WorldWideScience

Sample records for linac-based isocentric electron-photon

  1. Post mastectomy chest wall irradiation using mixed electron-photon beams with or without isocentric technique.

    Science.gov (United States)

    Hamdy, H K; Zikry, M S

    2008-01-01

    To describe our technique in delivering post mastectomy radiotherapy to chest wall using electron-photon mixed beam with or without isocentric application of the tangential photon portals, and to evaluate the associated acute and delayed morbidities. Twenty-two females with invasive breast cancer were subjected to modified radical mastectomy with adequate axillary dissection. All the patients have either tumour > or = 5 cm and/ or positive axillary nodes > 3. Chest wall was irradiated by a mixed beam of 6-Mev electrons (10Gy) and opposed tangential fields using 6 Mev-photons (36 Gy) followed by 6-Mev electrons boost to the scar of mastectomy for 4 Gy/2 fractions. We randomly allocated our patients to receive the photon beam with or without the isocentric technique. The mean dose to the planned target volume (PTV) by mixed beam was 44 Gy (96%) with a mean dose of 42 Gy (91%) to the overlying skin for the whole study group. In cases with right breast disease (17 cases), the mean right lung tissue volume within the PTV was 220 ml (15%). It was relatively higher with the non-iscocentric technique, 281 ml (19%), compared to the isocentric technique of 159 ml (10.5%). In cases with left breast disease (5 cases), the mean left lung volume within the PTV was 175 ml (14%). Larger volume of the lung tissue was included with the non-isocentric technique, 197 ml (16%) compared to the isocentric technique of 153 ml (12%). The mean scattered doses to the rest of the lung tissue, the rest of the heart in left breast cases, and the contra-lateral breast for the whole study group were 2.8 Gy, 1.8 Gy, and 1.4 Gy respectively and was comparable in both treatment arms. None of the cases developed any element of acute radiation related pneumonitis. Delayed radiation induced pneumonitis was seen in 2 cases (18%), with the chest wall treated with radiation with the non-isocentric technique. This study clearly demonstrated the utility of mixed beam in irradiating the chest wall after

  2. Setup verification in linac-based radiosurgery.

    Science.gov (United States)

    Falco, T; Lachaine, M; Poffenbarger, B; Podgorsak, E B; Fallone, B G

    1999-09-01

    A semi-automatic technique for the direct setup alignment of radiosurgical circular fields from an isocentric linac to treatment room laser cross-hairs is described. Alignment is achieved by acquiring images of the treatment room positioning laser cross-hairs superimposed on the radiosurgical circular field image. An alignment algorithm calculates the center of the radiosurgical field image as well as the intersection of the laser cross-hairs. This determines any alignment deviations and the information is then used to translate the radiosurgical collimator to its correct aligned position. Two detectors, each being sensitive to the lasers and ionizing radiation, were used to acquire the radiation/laser images. The first detector consists of a 0.3-mm-thick layer of photoconducting a-Se deposited on a 1.5-mm-thick copper plate and the second is film. The algorithm and detector system can detect deviations with a precision of approximately 0.04 mm. A device with gyroscopic degrees of freedom was built in order to firmly hold the detector at any orientation perpendicular to the radiosurgical beam axis. This device was used in conjunction with our alignment algorithm to quantify the isocentric sphere relative to the treatment room lasers over all gantry and couch angles used in dynamic stereotactic radiosurgery.

  3. Treatment of intracranial meningioma with linac based radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Kay, Chul Seung; Yoon, Sei Chul; Chung, Su Mi; Ryu, Mi Ryung; Kim, Yeon Sil; Suh, Tae Suk; Choi, Kyu Ho; Son, Byung Chul; Kim, Moon Chan [College of Medicine, Catholic Univ., Seoul (Korea, Republic of)

    2001-03-01

    To evaluate the role of linac based radiosurgery (RS) in the treatment of meningiomas, we retrospectively analyzed the results of clinical and follow up CT/MRI studies. From the 1988 July to 1998 April, twenty patients of meningioma had been treated with 6 MV linear accelerator based radiosurgery. Of the 20 patients, four (20%) were male and 16 (80%) were female. Mean age was 51 years old (22-78 years old). Majority of intracranial location of tumor for RS were parasagittal and sphenoid wing area. RS was done for primary treatment in 6 (30%), postoperative residual lesions in 11 (55%) and regrowth after surgery in 3 (15%). Mean tumor volume was 5.72 cm{sup 3} (0.78 - 15.1 cm{sup 3}) and secondary collimator size was 2.04 cm (1-3 cm). The periphery of tumor margin was prescribed with the mean dose of 19.6 Gy (9-30 Gy) which was 40-90% of the tumor center dose. The follow up duration ranged from 2.5 to 109 months (median 53 months). Annual CT/MRI scan was checked. By the follow up imaging studies, the tumor volume was reduced in 5 cases (25%), arrested growth in 14 cases (70%), and increased size in 1 case (15%). Among these responsive and stable 19 patients by imaging studies, there showed loss of contrast enhancement after CT/MRI in four patients. In clinical response, nine (45%) patients were considered improved condition, 10 (50%) patients were stable and one (5%) was worsened to be operated. This partly resulted in necrosis after surgery.The overall control rate of meningiomas with linac based RS was 95% by both imaging follow-up and clinical evaluation. With this results, linac based RS is considered safe and effective treatment method for meningioma.

  4. Status of the Linac based positron source at Saclay

    CERN Document Server

    Rey, J -M; Debu, P; Dzitko, H; Hardy, P; Liszkay, L; Lotrus, P; Muranaka, T; Noel, C; Perez, P; Pierret, O; Ruiz, N; Sacquin, Y

    2013-01-01

    Low energy positron beams are of major interest for fundamental science and materials science. IRFU has developed and built a slow positron source based on a compact, low energy (4.3 MeV) electron linac. The linac-based source will provide positrons for a magnetic storage trap and represents the first step of the GBAR experiment (Gravitational Behavior of Antimatter in Rest) recently approved by CERN for an installation in the Antiproton Decelerator hall. The installation built in Saclay will be described with its main characteristics. The ultimate target of the GBAR experiment will be briefly presented as well as the foreseen development of an industrial positron source dedicated for materials science laboratories.

  5. Coupled electron-photon radiation transport

    Energy Technology Data Exchange (ETDEWEB)

    Lorence, L.; Kensek, R.P.; Valdez, G.D.; Drumm, C.R.; Fan, W.C.; Powell, J.L.

    2000-01-17

    Massively-parallel computers allow detailed 3D radiation transport simulations to be performed to analyze the response of complex systems to radiation. This has been recently been demonstrated with the coupled electron-photon Monte Carlo code, ITS. To enable such calculations, the combinatorial geometry capability of ITS was improved. For greater geometrical flexibility, a version of ITS is under development that can track particles in CAD geometries. Deterministic radiation transport codes that utilize an unstructured spatial mesh are also being devised. For electron transport, the authors are investigating second-order forms of the transport equations which, when discretized, yield symmetric positive definite matrices. A novel parallelization strategy, simultaneously solving for spatial and angular unknowns, has been applied to the even- and odd-parity forms of the transport equation on a 2D unstructured spatial mesh. Another second-order form, the self-adjoint angular flux transport equation, also shows promise for electron transport.

  6. Radiosurgery with linac based photon knife in cerebral arteriovenous malformation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Hee; Choi, Tae Jin [College of Medicine, Keimyung Univ., Taegu (Korea, Republic of)

    2003-03-01

    The purpose of this study was to analyze the effect of a linear accelerator based Photon Knife Radiosurgery System developed by the staff of Keimyung University Dongsan Medical Center for the treatment of cerebral arteriovenous malformation. Between December 1993 and October 2000, 30 patients with cerebral arteriovenous malformation (AVM) were treated with the Linac based Photon Knife Radiosurgery System in the Department of Therapeutic Radiology at Keimyung University Dongsan Medical Center. The median age was 34, ranging from 7 to 63 years, with a 2: 1 male to female ratio. The locations of the AVM nidi were the frontal lobe (motor cortex), parietal lobe, and the thalamus, in that order. The diameters of the AVM nidi ranged 1.2 to 5.5 cm with a mean of 2.9 cm, and target volumes of between 0.5 and 20.6 cc, with a mean of 6.8 cc. The majority of patients received radiation doses of between 1,500 and 2,500 cGy, with a mean of 2,000 cGy, at 8O% the isodose line. Twenty-five patients were treated with one isocenter, 4 with two, and 1 with four. The follow-up radiological evaluations were performed with cranial computed tomogram (CT) or MRI between 6 month and one year interval, and if the AVM nidus had completely disappeared in the CT or MRI, we confirmed this was a complete obliteration, with a cerebral or magnetic resonance angiogram (MRA). The median follow-up period was 39 months with a range of 10 to 103 months. Twenty patients were radiologically followed up for over 20 months, with complete obliteration observed in 14 (70%). According to the maximal diameter. all four of the small AVM (<2 cm) completely obliterated, 8 of the 10 patients with a medium A VM (2 - 3 cm) showed a complete obliteration, and two showed partial obliteration, Among the patients with a large AVM (>3 cm), only one showed complete obliteration, and 5 showed partial obliteration, but 3 of these underwent further radiosurgery 3 years later. One who followed up for 20 months following

  7. Linac based photofission inspection system employing novel detection concepts

    Science.gov (United States)

    Stevenson, John; Gozani, Tsahi; Elsalim, Mashal; Condron, Cathie; Brown, Craig

    2011-10-01

    Rapiscan Systems is developing a LINAC based cargo inspection system for detection of special nuclear material (SNM) in cargo containers. The system, called Photofission Based Alarm Resolution (PBAR) is being developed under a DHD/DNDO Advanced Technology Demonstration (ATD) program. The PBAR system is based on the Rapiscan Eagle P9000 X-ray system, which is a portal system with a commercial 9 MeV LINAC X-ray source. For the purposes of the DNDO ATD program, a conveyor system was installed in the portal to allow scanning and precise positioning of 20 ft ISO cargo containers. The system uses a two step inspection process. In the first step, the basic scan, the container is quickly and completely inspected using two independent radiography arrays: the conventional primary array with high spatial resolution and a lower resolution spectroscopic array employing the novel Z-Spec method. The primary array uses cadmium tungstate (CdWO 4) detectors with conventional current mode readouts using photodiodes. The Z-Spec array uses small plastic scintillators capable of performing very fast (up to 10 8 cps) gamma-ray spectroscopy. The two radiography arrays are used to locate high-Z objects in the image such as lead, tungsten, uranium, which could be potential shielding materials as well as SNM itself. In the current system, the Z-Spec works by measuring the energy spectrum of transmitted X-rays. For high-Z materials the higher end of the energy spectrum is more attenuated than for low-Z materials and thus has a lower mean energy and a narrower width than low- and medium-Z materials. The second step in the inspection process is the direct scan or alarm clearing scan. In this step, areas of the container image, which were identified as high Z, are re-inspected. This is done by precisely repositioning the container to the location of the high-Z object and performing a stationary irradiation of the area with X-ray beam. Since there are a large number of photons in the 9 MV

  8. A Cherenkov radiator for FEL-synchronized VUV-pulses at a linac-based FEL

    NARCIS (Netherlands)

    Goloviznin, V. V.; Oepts, D.; van der Wiel, M. J.

    1997-01-01

    A possible way to carry out two-color IR+VUV pump-probe experiments at linac-based FELs is proposed. The idea is to supply an FEL facility with a gas cell filled with helium or hydrogen, so that the electron beam, upon passage through the undulator, could be used to generate ultraviolet Cherenkov

  9. Magnetic field contribution to the last electron-photon scattering

    OpenAIRE

    Giovannini, Massimo

    2010-01-01

    When the cosmic microwave photons scatter electrons just prior to the decoupling of matter and radiation, magnetic fields do contribute to the Stokes matrix as well as to the scalar, vector and tensor components of the transport equations for the brightness perturbations. The magnetized electron-photon scattering is hereby discussed in general terms by including, for the first time, the contribution of magnetic fields with arbitrary direction and in the presence of the scalar, vector and tens...

  10. Present and next steps of the JAERI superconducting rf linac based FEL program

    Energy Technology Data Exchange (ETDEWEB)

    Minehara, E.J.; Yamauchi, T.; Sugimoto, M. [FEL Laboratory at Tokai, Advanced Photon Research Center, Kansai Research Establishment, Japan Atomic Energy Research Institute, Tokai, Ibaraki (JP)] (and others)

    2000-03-01

    The JAERI superconducting rf linac based FEL has successfully been lased to produce a 0.3 kW FEL light and 100 kW or larger electron beam output in quasi continuous wave operation in 1999. The 1 kW class output as our present program goal will be achieved to improve the optical out coupling method in the FEL optical resonator, the electron gun, and the electron beam optics in the JAERI FEL driver. As our next 5 year program goal is the 100 kW class FEL light and a few tens MW class electron beam output in average, quasi continuous wave operation of the light and electron beam will be planned in the JAERI superconducting rf linac based FEL facility. Conceptual design options needed for such a very high power operation and shorter wavelength light sources will be discussed to improve and to upgrade the exciting facility. (author)

  11. An Electron/Photon/Relaxation Data Library for MCNP6

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, III, H. Grady [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-08-07

    The capabilities of the MCNP6 Monte Carlo code in simulation of electron transport, photon transport, and atomic relaxation have recently been significantly expanded. The enhancements include not only the extension of existing data and methods to lower energies, but also the introduction of new categories of data and methods. Support of these new capabilities has required major additions to and redesign of the associated data tables. In this paper we present the first complete documentation of the contents and format of the new electron-photon-relaxation data library now available with the initial production release of MCNP6.

  12. Study of Compton Broadening Due to Electron-Photon Scattering

    Directory of Open Access Journals (Sweden)

    Srinivasa Rao, M.

    2010-06-01

    Full Text Available We have investigated the effects of Compton broadening due to electron-photon scattering in hot stellar atmospheres. A purely electron-photon scattering media is assumed to have plane parallel geometry with an input radiation field localized on one side of the slab. The method is based on the discrete space theory of radiative transfer for the intensity of emitted radiation.The solution is developed to study the importance of scattering of radiation by free electrons in high temperature stellar atmospheres which produces a brodening and shift in spectral lines because of the Compton effect and the Doppler effect arising from mass and thermal motions of scattering electrons.It is noticed that the Comptonized spectrum depends on three parameters: the optical depth of the medium, the temperature of the thermal electrons and the viewing angle.We also showed that the Compton effect produces red shift and asymmetry in the line. These two effects increase as the optical depth increases. It is also noticed that the emergent specific intensities become completely asymmetric for higher optical depths.

  13. Long-term results of LINAC-based stereotactic radiosurgery for acoustic neuroma: The Greek experience

    Directory of Open Access Journals (Sweden)

    Kalogeridi Maria-Aggeliki

    2009-01-01

    Full Text Available Purpose: To estimate the value of LINAC-based stereotactic radiosurgery (SRS for the long-term local control of unilateral acoustic neuromas. Materials and Methods: Twenty patients (median age 66; range 57-80 years with unilateral acoustic neuroma underwent LINAC-based SRS from May 2000 through June 2004 with a dose of 11-12 Gy. The follow-up period ranged from 36 to 84 months (median follow-up period: 55 months. Before SRS none of the patients had useful hearing. The follow-up consisted of repeat imaging studies and clinical examination for assessment of facial and trigeminal nerve function at 6-month intervals for the first year and yearly thereafter. Results: Eleven tumors (58% decreased in size and eight (42% remained stable. One tumor showed a minor increase in size on the MRI done 6 months after SRS in comparison with the pretreatment MRI; however, a subsequent decrease was noticed on the next radiographic assessment and the tumor remained stable from then on. None of the tumors increased in size in the long-term follow-up, thus giving an overall growth control of 100% for the patients in this study. None of the patients had useful hearing before SRS, so hearing level was not assessed during follow-up. No patient developed new, permanent facial or trigeminal neuropathy. Conclusion: LINAC-based SRS with 11-12 Gy provides excellent tumor control in acoustic neuroma and has low toxicity even after long-term follow-up.

  14. Magnetic field contribution to the last electron-photon scattering

    CERN Document Server

    Giovannini, Massimo

    2010-01-01

    When the cosmic microwave photons scatter electrons just prior to the decoupling of matter and radiation, magnetic fields do contribute to the Stokes matrix as well as to the scalar, vector and tensor components of the transport equations for the brightness perturbations. The magnetized electron-photon scattering is hereby discussed in general terms by including, for the first time, the contribution of magnetic fields with arbitrary direction and in the presence of the scalar, vector and tensor modes of the geometry. The propagation of relic vectors and relic gravitons is discussed for a varying magnetic field orientation and for different photon directions. The source terms of the transport equations in the presence of the relativistic fluctuations of the geometry are also explicitly averaged over the magnetic field orientations and the problem of a consistent account of the small-scale and large-scale magnetic field is briefly outlined.

  15. Magnetic field contribution to the last electron-photon scattering

    Energy Technology Data Exchange (ETDEWEB)

    Giovannini, Massimo, E-mail: massimo.giovannini@cern.c [Department of Physics, Theory Division, CERN, 1211 Geneva 23 (Switzerland); INFN, Section of Milan-Bicocca, 20126 Milan (Italy)

    2010-11-21

    When the cosmic microwave photons scatter electrons just prior to the decoupling of matter and radiation, magnetic fields do contribute to the Stokes matrix as well as to the scalar, vector and tensor components of the transport equations for the brightness perturbations. The magnetized electron-photon scattering is hereby discussed in general terms by including, for the first time, the contribution of magnetic fields with arbitrary direction and in the presence of the scalar, vector and tensor modes of the geometry. The propagation of relic vectors and relic gravitons is discussed for a varying magnetic field orientation and for different photon directions. The source terms of the transport equations in the presence of the relativistic fluctuations of the geometry are also explicitly averaged over the magnetic field orientations and the problem of a consistent account of the small-scale and large-scale magnetic field is briefly outlined.

  16. Magnetic field contribution to the last electron-photon scattering

    Science.gov (United States)

    Giovannini, Massimo

    2010-11-01

    When the cosmic microwave photons scatter electrons just prior to the decoupling of matter and radiation, magnetic fields do contribute to the Stokes matrix as well as to the scalar, vector and tensor components of the transport equations for the brightness perturbations. The magnetized electron-photon scattering is hereby discussed in general terms by including, for the first time, the contribution of magnetic fields with arbitrary direction and in the presence of the scalar, vector and tensor modes of the geometry. The propagation of relic vectors and relic gravitons is discussed for a varying magnetic field orientation and for different photon directions. The source terms of the transport equations in the presence of the relativistic fluctuations of the geometry are also explicitly averaged over the magnetic field orientations and the problem of a consistent account of the small-scale and large-scale magnetic field is briefly outlined.

  17. Investigation of the accuracy of MV radiation isocentre calculations in the Elekta cone-beam CT software XVI

    DEFF Research Database (Denmark)

    Zimmermann, S. J.; Rowshanfarzad, P.; Ebert, M. A.

    2015-01-01

    radiation isocentre prior to routine use of the cone-beam CT system. The isocentre determination method used in the XVI software is not available to users. The aim of this work is to perform an independent evaluation of the Elekta XVI 4.5 software for isocentre verification with focus on the robustness......Purpose/Objective: Most modern radiotherapy treatments are based on cone-beam CT images to ensure precise positioning of the patient relative to the linac. This requires alignment of the cone-beam CT system to the linac MV radiation isocentre. Therefore, it is important to precisely localize the MV......) and the radiation field centre (RFC) is calculated. A software package was developed for accurate calculation of the linac isocentre position. This requires precise determination of the position of the ball bearing and the RFC. Results: Data were acquired for 6 MV, 18 MV and flattening filter free (FFF) 6 MV FFF...

  18. Simulations of mode reduction with an intracavity etalon in an RF-Linac based FEL

    Science.gov (United States)

    Oepts, D.; van der Meer, A. F. G.; Best, R. W. B.; van Amersfoort, P. W.; Colson, W. B.

    1989-12-01

    Coherence between successive light pulses from an rf-linac based FEL can be induced by means of an intracavity interferometric element such as an etalon. This considerably reduces the number of active cavity modes and facilitates the selection of a single narrow line from the laser output. Computer simulations for the operation of an etalon in the FELIX design are shown. The model based on the wave equation driven by single particles has been applied in simulations using a small number (up to six) of initially independent pulses. The case with 40 separate pulses in the cavity is treated with a simpler model. The simulations show that a low-finesse etalon suffices to obtain a large degree of coherence between successive pulses. Saturated operation in a reduced number of modes, but with the same total power, is attained with a delay of a few microseconds.

  19. JAERI superconducting RF linac-based free-electron laser-facility

    CERN Document Server

    Minehara, E J; Nagai, R; Kikuzawa, N; Sugimoto, M; Hajima, R; Shizuma, T; Yamauchi, T; Nishimori, N

    2000-01-01

    Recently, the JAERI superconducting RF linac based FEL has been successfully lased to produce 0.36 kW of FEL light using a 100 kW electron beam in quasi-continuous wave operation. A 1 kW class laser is our present program goal, and will be achieved by improving the optical out coupling in the FEL optical resonator, the electron gun, and the electron beam optics in the JAERI FEL driver. Our next 5-year program goal is to produce a 100 kW-class FEL laser and multi-MW class electron beam in average, quasi-continuous wave operation. Conceptual and engineering design options needed for such a very high-power operation will be discussed to improve and to upgrade the existing facility.

  20. Investigation of the accuracy of MV radiation isocentre calculations in the Elekta cone-beam CT software XVI

    DEFF Research Database (Denmark)

    Lynggaard Riis, Hans; Moltke, Lars N; Zimmermann, S. J.

    2016-01-01

    prior to treatment. Linac manufacturers offer tools for MV radiation isocentre localization. As a user, there is no access to the documentation for the underlying method and calculation algorithm used in the commercial software. The idea of this work was to evaluate the accuracy of the software tool......Accurate determination of the megavoltage (MV) radiation isocentre of a linear accelerator (linac) is an important task in radiotherapy. The localization of the MV radiation isocentre is crucial for correct calibration of the in-room lasers and the cone-beam CT scanner used for patient positioning...... for MV radiation isocentre calculation as delivered by Elekta using independent software. The image acquisition was based on the scheme designed by the manufacturer. Eight MV images were acquired in each series of a ball-bearing (BB) phantom attached to the treatment couch. The images were recorded...

  1. Linac-based total body irradiation (TBI) with volumetric modulated arc therapy (VMAT)

    Science.gov (United States)

    Tas, B.; Durmus, I. F.; Okumus, A.; Uzel, O. E.

    2017-02-01

    To evaluate dose distribution of Volumetric modulated arc therapy (VMAT) planning tecnique using Versa HD® lineer accelerator to deliver Total Body Irradiation (TBI) on the coach. Eight TBI patient's Treatment Planning System (TPS) were performed with dual arc VMAT for each patient. The VMAT-TBI consisted of three isocentres and three dual overlapping arcs. The prescribed dose was 12 Gy. Mean dose to lung and kidney were restricted less than 10 Gy and max. dose to lens were restricted less than 6 Gy. The plans were verified using 2D array and ion chamber. The comparison between calculation and measurement were made by γ-index analysis and absolute dose. An average total delivery time was determined 923±34 seconds and an average MU was determined 2614±228 MUs for dual arc VMAT. Mean dose to lungs was 9.7±0.2 Gy, mean dose to kidneys was 8.8±0.3 Gy, max. dose to lens was 5.5±0.3 Gy and max. dose was 14.6±0.3 Gy, HI of PTV was 1.13±0.2, mean dose to PTV was 12.6±1.5 Gy and mean γ-index pass rate was %97.1±1.9. The results show that the tecnique for TBI using VMAT on the treatment coach is feasible.

  2. Analytical bunch compression studies for a linac-based electron accelerator

    Directory of Open Access Journals (Sweden)

    M. Schreck

    2015-10-01

    Full Text Available The current paper deals with analytical bunch compression studies for FLUTE whose results are compared to simulations. FLUTE is a linac-based electron accelerator with a design energy of approximately 40 MeV currently being constructed at the Karlsruhe Institute of Technology. One of the goals of FLUTE is to generate electron bunches with their length lying in the femtosecond regime. In the first phase this will be accomplished using a magnetic bunch compressor. This compressor forms the subject of the studies presented. The paper is divided into two parts. The first part deals with pure geometric investigations of the bunch compressor where space charge effects and the backreaction of bunches with coherent synchrotron radiation are neglected. The second part is dedicated to the treatment of space charge effects. The upshot is that the analytical results in the two parts agree quite well with what is obtained from simulations. This paper shall form the basis for future analytical studies of the FLUTE bunch compressor and of bunch compression, in general.

  3. A Recirculating Linac-Based Facility for Ultrafast X-Ray Science

    Energy Technology Data Exchange (ETDEWEB)

    J. N. Corlett; W. A. Barletta; S. DeSantis; L. Doolittle; W. M. Fawley; M.A. Green; P. Heimann; S. Leone; S. Lidia; D. Li; A. Ratti; K. Robinson; R. Schoenlein; J. Staples; W. Wan; R. Wells; A.Wolski; A. Zholents; F. Parmigiani; M. Placidi; W. Pirkl; R. A. Rimmer; S. Wang

    2003-05-01

    We present an updated design for a proposed source of ultra-fast synchrotron radiation pulses based on a recirculating superconducting linac [1,2], in particular the incorporation of EUV and soft x-ray production. The project has been named LUX--Linac-based Ultrafast X-ray facility. The source produces intense x-ray pulses with duration of 10-100 fs at a 10 kHz repetition rate, with synchronization of 10's fs, optimized for the study of ultra-fast dynamics. The photon range covers the EUV to hard x-ray spectrum by use of seeded harmonic generation in undulators, and a specialized technique for ultra-short pulse photon production in the 1-10 keV range. High brightness rf photocathodes produce electron bunches which are optimized either for coherent emission in free electron lasers, or to provide a large x/y emittance ration and small vertical emittance which allows for manipulation to produce short-pulse hard x-rays. An injector linac accelerates the beam to 120 MeV, and is followed by f our passes through a 600-720 MeV recirculating linac. We outline the major technical components of the proposed facility.

  4. A recirculating linac-based facility for ultrafast X-ray science

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, J.N; Barletta, W.A.; DeSantis, S.; Doolittle, L.; Fawley, W.M.; Green, M.A.; Heimann, P.; Leone, S.; Lidia, S.; Li, D.; Ratti, A.; Robinson, K.; Schoenlein, R.; Staples, J.; Wan, W.; Wells, R.; Wolski, A.; Zholents, A.; Placidi, M.; Pirkl, W.; Parmigiani, F.

    2003-05-06

    We present an updated design for a proposed source of ultra-fast synchrotron radiation pulses based on a recirculating superconducting linac, in particular the incorporation of EUV and soft x-ray production. The project has been named LUX - Linac-based Ultrafast X-ray facility. The source produces intense x-ray pulses with duration of 10-100 fs at a 10 kHz repetition rate, with synchronization of 10 s fs, optimized for the study of ultra-fast dynamics. The photon range covers the EUV to hard x-ray spectrum by use of seeded harmonic generation in undulators, and a specialized technique for ultra-short-pulse photon production in the 1-10 keV range. High-brightness rf photocathodes produce electron bunches which are optimized either for coherent emission in free-electron lasers, or to provide a large x/y emittance ration and small vertical emittance which allows for manipulation to produce short-pulse hard x-rays. An injector linac accelerates the beam to 120 MeV, and is followed by four passes through a 600-720 MeV recirculating linac. We outline the major technical components of the proposed facility.

  5. A tunable, linac based, intense, broad-band THz source forpump-probe experiments

    Energy Technology Data Exchange (ETDEWEB)

    Schmerge, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Adolphsen, C. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Corbett, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Dolgashev, V. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Durr, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fazio, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fisher, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Frisch, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Gaffney, K. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Guehr, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hastings, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hettel, B. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hoffmann, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hogan, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Holtkamp, N. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Huang, X. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Huang, Z. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Kirchmann, P. [SLAC National Accelerator Lab., Menlo Park, CA (United States); LaRue, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Limborg, C. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Lindenberg, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Loos, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Maxwell, T. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Nilsson, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Raubenheimer, T. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Reis, D. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Ross, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Shen, Z. -X. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stupakov, G. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Tantawi, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Tian, K. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Wu, Z. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Xiang, D. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Yakimenko, V. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-02-02

    We propose an intense THz source with tunable frequency and bandwidth that can directly interact with the degrees of freedom that determine the properties of materials and thus provides a new tool for controlling and directing these ultrafast processes as well as aiding synthesis of new materials with new functional properties. This THz source will broadly impact our understanding of dynamical processes in matter at the atomic-scale and in real time. Established optical pumping schemes using femtosecond visible frequency laser pulses for excitation are extended into the THz frequency regime thereby enabling resonant excitation of bonds in correlated solid state materials (phonon pumping), to drive low energy electronic excitations, to trigger surface chemistry reactions, and to all-optically bias a material with ultrashort electric fields or magnetic fields. A linac-based THz source can supply stand-alone experiments with peak intensities two orders of magnitude stronger than existing laser-based sources, but when coupled with atomic-scale sensitive femtosecond x-ray probes it opens a new frontier in ultrafast science with broad applications to correlated materials, interfacial and liquid phase chemistry, and materials in extreme conditions.

  6. Project for the development of the linac based NCT facility in University of Tsukuba.

    Science.gov (United States)

    Kumada, H; Matsumura, A; Sakurai, H; Sakae, T; Yoshioka, M; Kobayashi, H; Matsumoto, H; Kiyanagi, Y; Shibata, T; Nakashima, H

    2014-06-01

    A project team headed by University of Tsukuba launched the development of a new accelerator based BNCT facility. In the project, we have adopted Radio-Frequency Quadrupole (RFQ)+Drift Tube Linac (DTL) type linac as proton accelerators. Proton energy generated from the linac was set to 8MeV and average current was 10mA. The linac tube has been constructed by Mitsubishi Heavy Industry Co. For neutron generator device, beryllium is selected as neutron target material; high intensity neutrons are generated by the reaction with beryllium and the 80kW proton beam. Our team chose beryllium as the neutron target material. At present beryllium target system is being designed with Monte-Carlo estimations and heat analysis with ANSYS. The neutron generator consists of moderator, collimator and shielding. It is being designed together with the beryllium target system. We also acquired a building in Tokai village; the building has been renovated for use as BNCT treatment facility. It is noteworthy that the linac tube had been installed in the facility in September 2012. In BNCT procedure, several medical devices are required for BNCT treatment such as treatment planning system, patient positioning device and radiation monitors. Thus these are being developed together with the linac based neutron source. For treatment planning system, we are now developing a new multi-modal Monte-Carlo treatment planning system based on JCDS. The system allows us to perform dose estimation for BNCT as well as particle radiotherapy and X-ray therapy. And the patient positioning device can navigate a patient to irradiation position quickly and properly. Furthermore the device is able to monitor movement of the patient׳s position during irradiation.

  7. Viability of an isocentric cobalt-60 teletherapy unit for stereotactic radiosurgery.

    Science.gov (United States)

    Poffenbarger, B A; Podgorsak, E B

    1998-10-01

    The potential for radiosurgery with an isocentric teletherapy cobalt unit was evaluated in three areas: (1) the physical properties of radiosurgical beams, (2) the quality of radiosurgical dose distributions obtained with four to ten noncoplanar converging arcs, and (3) the accuracy with which the radiosurgical dose can be delivered. In each of these areas the cobalt unit provides a viable alternative to an isocentric linear accelerator (linac) as a radiation source for radiosurgery. A 10 MV x-ray beam from a linac used for radiosurgery served as a standard for comparison. The difference between the 80%-20% penumbras of stationary radiosurgical fields in the nominal diameter range from 10 to 40 mm of the cobalt-60 and 10 MV photon beams is remarkably small, with the cobalt-60 beam penumbras, on average, only about 0.7 mm larger than those of the linac beam. Differences between the cobalt-60 and 10 MV radiosurgical treatment plans in terms of dose homogeneity within the target volume, conformity of the prescribed isodose volume to the target volume, and dose falloffs outside the target volume are also minimal, and therefore of essentially no clinical significance. Moreover, measured isodose distributions for a radiosurgical procedure on our Theratron T-780 cobalt unit agreed with calculated distributions to within the +/- 1 mm spatial and +/- 5% numerical dose tolerances, which are generally specified for radiosurgery. The viability of isocentric cobalt units for radiosurgery will be of particular interest to centers in developing countries where cobalt units, because of their relatively low costs, provide the only megavoltage source of radiation for radiotherapy, and could easily and inexpensively be modified for radiosurgery. Of course, the quality assurance protocols and mechanical condition of a particular teletherapy cobalt unit must meet stringent requirements before the use of the unit for radiosurgery can be advocated.

  8. Beam-transport study of an isocentric rotating ion gantry with minimum number of quadrupoles

    Energy Technology Data Exchange (ETDEWEB)

    Pavlovic, Marius [Department of Nuclear Physics and Technology, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, SK-812 19 Bratislava, Slovak Republic (Slovakia); Forschungs- und Technologietransfer GmbH (Fotec), Viktor-Kaplan 2, A-2700 Wiener Neustadt (Austria)]. E-mail: marius.pavlovic@stuba.sk; Griesmayer, Erich [Forschungs- und Technologietransfer GmbH (Fotec), Viktor-Kaplan 2, A-2700 Wiener Neustadt (Austria); Seemann, Rolf [Forschungs- und Technologietransfer GmbH (Fotec), Viktor-Kaplan 2, A-2700 Wiener Neustadt (Austria)

    2005-06-11

    A beam-transport study of an isocentric gantry for ion therapy is presented. The gantry is designed with the number of quadrupoles down to the theoretical minimum, which is the feature published for the first time in this paper. This feature has been achieved without compromising the ion-optical functions of the beam-transport system that is capable of handling non-symmetric beams (beams with different emittances in vertical and horizontal plane), pencil-beam scanning, double-achromatic optics and beam-size control. Ion-optical properties of the beam-transport system are described, discussed and illustrated by computer simulations performed by the TRANSPORT-code.

  9. Electron-photon shower distribution function tables for lead, copper and air absorbers

    CERN Document Server

    Messel, H

    2013-01-01

    Electron-Photon Shower Distribution Function: Tables for Lead, Copper and Air Absorbers presents numerical results of the electron-photon shower distribution function for lead, copper, and air absorbers. Electron or photon interactions, including Compton scattering, elastic Coulomb scattering, and the photo-electric effect, are taken into account in the calculations. This book consists of four chapters and begins with a review of both theoretical and experimental work aimed at deducing the characteristics of the cascade produced from the propagation of high energy electrons and photons through

  10. Compact Short-Pulsed Electron Linac Based Neutron Sources for Precise Nuclear Material Analysis

    Science.gov (United States)

    Uesaka, M.; Tagi, K.; Matsuyama, D.; Fujiwara, T.; Dobashi, K.; Yamamoto, M.; Harada, H.

    2015-10-01

    An X-band (11.424GHz) electron linac as a neutron source for nuclear data study for the melted fuel debris analysis and nuclear security in Fukushima is under development. Originally we developed the linac for Compton scattering X-ray source. Quantitative material analysis and forensics for nuclear security will start several years later after the safe settlement of the accident is established. For the purpose, we should now accumulate more precise nuclear data of U, Pu, etc., especially in epithermal (0.1-10 eV) neutrons. Therefore, we have decided to modify and install the linac in the core space of the experimental nuclear reactor "Yayoi" which is now under the decommission procedure. Due to the compactness of the X-band linac, an electron gun, accelerating tube and other components can be installed in a small space in the core. First we plan to perform the time-of-flight (TOF) transmission measurement for study of total cross sections of the nuclei for 0.1-10 eV energy neutrons. Therefore, if we adopt a TOF line of less than 10m, the o-pulse length of generated neutrons should be shorter than 100 ns. Electronenergy, o-pulse length, power, and neutron yield are ~30 MeV, 100 ns - 1 micros, ~0.4 kW, and ~1011 n/s (~103 n/cm2/s at samples), respectively. Optimization of the design of a neutron target (Ta, W, 238U), TOF line and neutron detector (Ce:LiCAF) of high sensitivity and fast response is underway. We are upgrading the electron gun and a buncher to realize higher current and beam power with a reasonable beam size in order to avoid damage of the neutron target. Although the neutron flux is limited in case of the X-band electron linac based source, we take advantage of its short pulse aspect and availability for nuclear data measurement with a short TOF system. First, we form a tentative configuration in the current experimental room for Compton scattering in 2014. Then, after the decommissioning has been finished, we move it to the "Yayoi" room and perform

  11. Investigation of the accuracy of MV radiation isocentre calculations in the Elekta cone-beam CT software XVI.

    Science.gov (United States)

    Riis, Hans L; Moltke, Lars N; Zimmermann, Sune J; Ebert, Martin A; Rowshanfarzad, Pejman

    2016-06-07

    Accurate determination of the megavoltage (MV) radiation isocentre of a linear accelerator (linac) is an important task in radiotherapy. The localization of the MV radiation isocentre is crucial for correct calibration of the in-room lasers and the cone-beam CT scanner used for patient positioning prior to treatment. Linac manufacturers offer tools for MV radiation isocentre localization. As a user, there is no access to the documentation for the underlying method and calculation algorithm used in the commercial software. The idea of this work was to evaluate the accuracy of the software tool for MV radiation isocentre calculation as delivered by Elekta using independent software. The image acquisition was based on the scheme designed by the manufacturer. Eight MV images were acquired in each series of a ball-bearing (BB) phantom attached to the treatment couch. The images were recorded at cardinal angles of the gantry using the electronic portal imaging device (EPID). Eight Elekta linacs with three different types of multileaf collimators (MLCs) were included in the test. The influence of MLC orientation, x-ray energy, and phantom modifications were examined. The acquired images were analysed using the Elekta x-ray volume imaging (XVI) software and in-house developed (IHD) MATLAB code. Results from the two different software were compared. A discrepancy in the longitudinal direction of the isocentre localization was found averaging 0.23 mm up to a maximum of 0.75 mm. The MLC orientation or the phantom asymmetry in the longitudinal direction do not appear to cause the discrepancy. The main cause of the differences could not be clearly identified. However, it is our opinion that the commercial software delivered by the linac manufacturer should be improved to reach better stability and precise results in the MV radiation isocentre calculations.

  12. Investigation of the accuracy of MV radiation isocentre calculations in the Elekta cone-beam CT software XVI

    Science.gov (United States)

    Riis, Hans L.; Moltke, Lars N.; Zimmermann, Sune J.; Ebert, Martin A.; Rowshanfarzad, Pejman

    2016-06-01

    Accurate determination of the megavoltage (MV) radiation isocentre of a linear accelerator (linac) is an important task in radiotherapy. The localization of the MV radiation isocentre is crucial for correct calibration of the in-room lasers and the cone-beam CT scanner used for patient positioning prior to treatment. Linac manufacturers offer tools for MV radiation isocentre localization. As a user, there is no access to the documentation for the underlying method and calculation algorithm used in the commercial software. The idea of this work was to evaluate the accuracy of the software tool for MV radiation isocentre calculation as delivered by Elekta using independent software. The image acquisition was based on the scheme designed by the manufacturer. Eight MV images were acquired in each series of a ball-bearing (BB) phantom attached to the treatment couch. The images were recorded at cardinal angles of the gantry using the electronic portal imaging device (EPID). Eight Elekta linacs with three different types of multileaf collimators (MLCs) were included in the test. The influence of MLC orientation, x-ray energy, and phantom modifications were examined. The acquired images were analysed using the Elekta x-ray volume imaging (XVI) software and in-house developed (IHD) MATLAB code. Results from the two different software were compared. A discrepancy in the longitudinal direction of the isocentre localization was found averaging 0.23 mm up to a maximum of 0.75 mm. The MLC orientation or the phantom asymmetry in the longitudinal direction do not appear to cause the discrepancy. The main cause of the differences could not be clearly identified. However, it is our opinion that the commercial software delivered by the linac manufacturer should be improved to reach better stability and precise results in the MV radiation isocentre calculations.

  13. Simple isocentric technique for irradiation of the breast, chest wall and peripheral lymphatics

    Energy Technology Data Exchange (ETDEWEB)

    Podgorsak, E.B.; Gosselin, M.; Pla, M.; Kim, T.H.; Freeman, C.R. (McGill Univ., Montreal, Quebec (Canada). Dept. of Radiation Oncology)

    1984-01-01

    The major problem with the standard technique for irradiation of the breast or chest wall and peripheral lymphatics is field matching at the junction between the supraclavicular and tangential fields. Overdosing or underdosing across the junctions is unavoidable because of beam divergence. Various techniques using a half-blocked supraclavicular field in conjunction with special tangential fields have been introduced recently to eliminate the junction problem; they are, however, complicated, involving couch motions and machine isocentre repositioning when changing from the supraclavicular to the tangential fields. The breast treatment technique used by the authors over the past twelve months utilises a supraclavicular half-blocked field, two tangential half-blocked fields and an optional posterior axillary field. The technique is simple and easy to set up since the same machine isocentre is used for all treatment fields and no couch movement or patient repositioning is required. The same half-block collimator used to define the caudad border of the supraclavicular field is used to define the cephalad edges of the two tangential fields. The margin of error of treatment is reduced and the dose measurements demonstrate excellent dose homogeneity through the entire treatment volume with no overdose or underdose at the field junction.

  14. Image quality and dose distributions of three linac-based imaging modalities

    Energy Technology Data Exchange (ETDEWEB)

    Dzierma, Yvonne; Ames, Evemarie; Nuesken, Frank; Palm, Jan; Licht, Norbert; Ruebe, Christian [Universitaetsklinikum des Saarlandes, Klinik fuer Strahlentherapie und Radioonkologie, Homburg/Saar (Germany)

    2015-04-01

    Linac-based patient imaging is possible with a variety of techniques using different photon energies. The purpose of this work is to compare three imaging systems operating at 6 MV, flattening free filter (FFF) 1 MV, and 121 kV. The dose distributions of all pretreatment set-up images (over 1,000) were retrospectively calculated on the planning computed tomography (CT) images for all patients with prostate and head-and-neck cancer treated at our institution in 2013. We analyzed the dose distribution and the dose to organs at risk. For head-and-neck cancer patients, the imaging dose from 6-MV cone beam CT (CBCT) reached maximum values at around 8 cGy. The 1-MV CBCT dose was about 63-79 % of the 6-MV CBCT dose for all organs at risk. Planar imaging reduced the imaging dose from CBCT to 30-40 % for both megavoltage modalities. The dose from the kilovoltage CBCT was 4-10 % of the 6-MV CBCT dose. For prostate cancer patients, the maximum dose from 6-MV CBCT reached 13-15 cGy, and was reduced to 66-73 % for 1 MV. Planar imaging reduces the MV CBCT dose to 10-20 %. The kV CBCT dose is 15-20 % of the 6-MV CBCT dose, slightly higher than the dose from MV axes. The dose distributions differ markedly in response to the different beam profiles and dose-depth characteristics. (orig.) [German] Linac-basierte Bildgebung zur Patientenlagerung ist mit einer Vielzahl von Techniken unterschiedlicher Photonenenergien moeglich. Ziel dieser Arbeit ist der Vergleich dreier Bildgebungssysteme mit 6 MV (Megavolt), FFF 1 MV, und 121 kV (Kilovolt). Fuer alle im Jahr 2013 an unserer Klinik behandelten Prostata- und HNO-Patienten wurden retrospektiv die Dosisverteilungen aller Verifikationsaufnahmen (ueber 1000 insgesamt) auf der Planungs-Computertomographie (CT) berechnet. Wir analysierten die Dosisverteilung und die Dosis an den Risikoorganen. Bei HNO-Patienten erreichte die Dosis von 6 MV ''Cone-beam''-CT (CBCT)Maximalwerte um 8 cGy. Mit 1 MV wird die Dosis auf 63

  15. Isocentric rotational performance of the Elekta Precise Table studied using a USB-microscope

    DEFF Research Database (Denmark)

    Riis, Hans L; Zimmermann, Sune J; Riis, Poul

    2010-01-01

    position relative to the pointer tip. The table performance was mapped in terms of USB-microscope images of the pointer tip at different table angles and load configurations. The USB-microscope was used as a detector to measure the pointer tip positions with a resolution down to 0.01 mm. A new elastic...... fitting technique. A new method to ensure optimal positioning of the table relative to the accelerator is presented. This method cannot eliminate systematic errors completely. To eliminate systematic errors we suggest that geometric and elastic models of the table and accelerator gantry arm......The isocentric three-dimensional performance of the Elekta Precise Table was investigated. A pointer was attached to the radiation head of the accelerator and positioned at the geometric rotational axis of the head. A USB-microscope was mounted on the treatment tabletop to measure the table...

  16. Respiratory correlated cone-beam computed tomography on an isocentric C-arm

    Energy Technology Data Exchange (ETDEWEB)

    Kriminski, Sergey [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Mitschke, Matthias [Siemens Medical Solutions USA, Inc. Oncology Care Systems, Concord, CA 94520 (United States); Sorensen, Stephen [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Wink, Nicole M [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Chow, Phillip E [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Tenn, Steven [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Solberg, Timothy D [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Jonsson Comprehensive Cancer Center, Los Angeles, CA 90095 (United States); University of Nebraska Medical Center, Omaha, NE 68102 (United States)

    2005-11-21

    A methodology for 3D image reconstruction from retrospectively gated cone-beam CT projection data has been developed. A mobile x-ray cone-beam device consisting of an isocentric C-arm equipped with a flat panel detector was used to image a moving phantom. Frames for reconstruction were retrospectively selected from complete datasets based on the known rotation of the C-arm and a signal from a respiratory monitor. Different sizes of gating windows were tested. A numerical criterion for blur on the reconstructed image was suggested. The criterion is based on minimization of an Ising energy function, similar to approaches used in image segmentation or restoration. It is shown that this criterion can be used for the determination of the optimal gating window size. Images reconstructed from the retrospectively gated projection sequences using the optimal gating window data showed a significant improvement compared to images reconstructed from the complete projection datasets.

  17. Respiratory correlated cone-beam computed tomography on an isocentric C-arm

    Science.gov (United States)

    Kriminski, Sergey; Mitschke, Matthias; Sorensen, Stephen; Wink, Nicole M.; Chow, Phillip E.; Tenn, Steven; Solberg, Timothy D.

    2005-11-01

    A methodology for 3D image reconstruction from retrospectively gated cone-beam CT projection data has been developed. A mobile x-ray cone-beam device consisting of an isocentric C-arm equipped with a flat panel detector was used to image a moving phantom. Frames for reconstruction were retrospectively selected from complete datasets based on the known rotation of the C-arm and a signal from a respiratory monitor. Different sizes of gating windows were tested. A numerical criterion for blur on the reconstructed image was suggested. The criterion is based on minimization of an Ising energy function, similar to approaches used in image segmentation or restoration. It is shown that this criterion can be used for the determination of the optimal gating window size. Images reconstructed from the retrospectively gated projection sequences using the optimal gating window data showed a significant improvement compared to images reconstructed from the complete projection datasets.

  18. Retrospective analysis of linac-based radiosurgery for arteriovenous malformations and testing of the Flickinger formula in predicting radiation injury

    Energy Technology Data Exchange (ETDEWEB)

    Cetin, I.A. [Universitair Ziekenhuis Brussel (Belgium). Dept. of Radiation Oncology; Marmara Univ., Ustkaynarca/Pendik (Turkey). Dept. of Radiation Oncology; Ates, R.; Dhaens, J.; Storme, G. [Universitair Ziekenhuis Brussel (Belgium). Dept. of Radiation Oncology

    2012-12-15

    Background and purpose: The aim of the study was to validate the use of linac-based radiosurgery in arteriovenous malformation (AVM) patients and to predict complications using an integrated logistic formula (ILF) in comparison with clinical outcomes. Patients and methods: The results of radiosurgery in 92 AVM patients were examined. All patients were treated with linac-based radiosurgery. Of these, 70 patients were followed for 12-45 months (median, 24 months) and were analyzed. The treated volume varied from 0.09 to 26.95 cm{sup 3} (median, 2.3 cm{sup 3}) and the median marginal dose was 20 Gy (range, 10.4-22). The median 12-Gy volume was 9.94 cm{sup 3} (range, 0.74-60.09 cm{sup 3}). Patients and lesion characteristics potentially affecting nidus obliteration and excellent outcome were evaluated by performing a log-rank test and univariate and multivariate analyses. The risk for radiation injury (RRI) was calculated with an integrated logistic formula. The predictive power of the RRI was assessed by calculating the area under the receiver operating characteristic (ROC) curve. Results: Follow-up magnetic resonance (MR) angiography revealed complete AVM obliteration in 56 of 70 patients. The MR angiography confirmed an obliteration rate of 80%. The annual hemorrhage rate was 1.4% for the first 2 years after radiosurgery and 0% thereafter. The number of patients with an excellent outcome was 48 (68%). Factors associated with better obliteration were higher radiation dose to the lesion margins [12-Gy volume (V12) > 10 cm{sup 3}], small volume, and a Pollock-Flickinger score less than 1.49; those predicting excellent outcomes were V12 < 10 cm{sup 3}, small volume, and Pollock-Flickinger score less than 1.49, as determined by multivariate analyses. Factors associated with radiation injury were V12 > 10 cm{sup 3} (p=0.03) and volume greater than 2 cm{sup 3} (p=0.001), as determined by a univariate analysis. The analyses showed an ROC of 0.66. Conclusion: These data

  19. PENELOPE, and algorithm and computer code for Monte Carlo simulation of electron-photon showers

    Energy Technology Data Exchange (ETDEWEB)

    Salvat, F.; Fernandez-Varea, J.M.; Baro, J.; Sempau, J.

    1996-10-01

    The FORTRAN 77 subroutine package PENELOPE performs Monte Carlo simulation of electron-photon showers in arbitrary for a wide energy range, from similar{sub t}o 1 KeV to several hundred MeV. Photon transport is simulated by means of the standard, detailed simulation scheme. Electron and positron histories are generated on the basis of a mixed procedure, which combines detailed simulation of hard events with condensed simulation of soft interactions. A simple geometry package permits the generation of random electron-photon showers in material systems consisting of homogeneous bodies limited by quadric surfaces, i.e. planes, spheres cylinders, etc. This report is intended not only to serve as a manual of the simulation package, but also to provide the user with the necessary information to understand the details of the Monte Carlo algorithm.

  20. PENELOPE, an algorithm and computer code for Monte Carlo simulation of electron-photon showers

    Energy Technology Data Exchange (ETDEWEB)

    Salvat, F.; Fernandez-Varea, J.M.; Baro, J.; Sempau, J.

    1996-07-01

    The FORTRAN 77 subroutine package PENELOPE performs Monte Carlo simulation of electron-photon showers in arbitrary for a wide energy range, from 1 keV to several hundred MeV. Photon transport is simulated by means of the standard, detailed simulation scheme. Electron and positron histories are generated on the basis of a mixed procedure, which combines detailed simulation of hard events with condensed simulation of soft interactions. A simple geometry package permits the generation of random electron-photon showers in material systems consisting of homogeneous bodies limited by quadric surfaces, i.e. planes, spheres, cylinders, etc. This report is intended not only to serve as a manual of the simulation package, but also to provide the user with the necessary information to understand the details of the Monte Carlo algorithm. (Author) 108 refs.

  1. Investigating a multi-purpose target for electron linac based photoneutron sources for BNCT of deep-seated tumors

    Energy Technology Data Exchange (ETDEWEB)

    Masoudi, S. Farhad, E-mail: masoudi@kntu.ac.ir; Rasouli, Fatemeh S.

    2015-08-01

    Recent studies in BNCT have focused on investigating appropriate neutron sources as alternatives for nuclear reactors. As the most prominent facilities, the electron linac based photoneutron sources benefit from two consecutive reactions, (e, γ) and (γ, n). The photoneutron sources designed so far are composed of bipartite targets which involve practical problems and are far from the objective of achieving an optimized neutron source. This simulation study deals with designing a compact, optimized, and geometrically simple target for a photoneutron source based on an electron linac. Based on a set of MCNPX simulations, tungsten is found to have the potential of utilizing as both photon converter and photoneutron target. Besides, it is shown that an optimized dimension for such a target slows-down the produced neutrons toward the desired energy range while keeping them economy, which makes achieving the recommended criteria for BNCT of deep-tumors more available. This multi-purpose target does not involve complicated designing, and can be considered as a significant step toward finding application of photoneutron sources for in-hospital treatments. In order to shape the neutron beam emitted from such a target, the beam is planned to pass through an optimized arrangement of materials composed of moderators, filters, reflector, and collimator. By assessment with the recommended in-air parameters, it is shown that the designed beam provides high intensity of desired neutrons, as well as low background contamination. The last section of this study is devoted to investigate the performance of the resultant beam in deep tissue. A typical simulated liver tumor, located within a phantom of human body, was subjected to the irradiation of the designed spectrum. The dosimetric results, including evaluated depth-dose curves and carried out in-phantom parameters show that the proposed configuration establishes acceptable agreement between the appropriate neutron intensity, and

  2. Adjuvant therapy after resection of brain metastases. Frameless image-guided LINAC-based radiosurgery and stereotactic hypofractionated radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Broemme, J.; Aebersold, D.M.; Pica, A. [Bern Univ., Bern Univ. Hospital (Switzerland). Dept. of Radiation Oncology; Abu-Isa, J.; Beck, J.; Raabe, A. [Bern Univ., Bern Univ. Hospital (Switzerland). Neurosurgery; Kottke, R.; Wiest, R. [Bern Univ., Bern Univ. Hospital (Switzerland). Neuroradiology; Malthaner, M.; Schmidhalter, D. [Bern Univ., Bern Univ. Hospital (Switzerland). Div. of Medical Radiation Physics

    2013-09-15

    Background: Tumor bed stereotactic radiosurgery (SRS) after resection of brain metastases is a new strategy to delay or avoid whole-brain irradiation (WBRT) and its associated toxicities. This retrospective study analyzes results of frameless image-guided linear accelerator (LINAC)-based SRS and stereotactic hypofractionated radiotherapy (SHRT) as adjuvant treatment without WBRT. Materials and methods: Between March 2009 and February 2012, 44 resection cavities in 42 patients were treated with SRS (23 cavities) or SHRT (21 cavities). All treatments were delivered using a stereotactic LINAC. All cavities were expanded by {>=} 2 mm in all directions to create the clinical target volume (CTV). Results: The median planning target volume (PTV) for SRS was 11.1 cm{sup 3}. The median dose prescribed to the PTV margin for SRS was 17 Gy. Median PTV for SHRT was 22.3 cm{sup 3}. The fractionation schemes applied were: 4 fractions of 6 Gy (5 patients), 6 fractions of 4 Gy (6 patients) and 10 fractions of 4 Gy (10 patients). Median follow-up was 9.6 months. Local control (LC) rates after 6 and 12 months were 91 and 77 %, respectively. No statistically significant differences in LC rates between SRS and SHRT treatments were observed. Distant brain control (DBC) rates at 6 and 12 months were 61 and 33 %, respectively. Overall survival (OS) at 6 and 12 months was 87 and 63.5 %, respectively, with a median OS of 15.9 months. One patient treated by SRS showed symptoms of radionecrosis, which was confirmed histologically. Conclusion: Frameless image-guided LINAC-based adjuvant SRS and SHRT are effective and well tolerated local treatment strategies after resection of brain metastases in patients with oligometastatic disease. (orig.)

  3. LEPS2 : the second Laser-Electron Photon facility at SPring-8

    Science.gov (United States)

    Yosoi, M.

    2011-10-01

    A new project to construct the second beamline for the laser-electron photon beam at SPring-8 (LEPS2) has started. Based on the LEPS experience, the project aims to improve the intensity of the photon beam and to expand the detector acceptance by adopting the BNL-E949 detector, which is a hermetic detector in a large 1 T solenoid magnet. The central region of tracking chambers will be upgraded for the LEPS2. A new LEPS2 experimental building has just been constructed outside the experimental hall of the storage ring. The present status of the development of a frozen-spin polarized HD target is also reported.

  4. Single-shot method for measuring femtosecond bunch length in linac-based free-electron lasers

    Directory of Open Access Journals (Sweden)

    Z. Huang

    2010-09-01

    Full Text Available There is growing interest in the generation and characterization of femtosecond and subfemtosecond pulses from linac-based free-electron lasers (FELs. In this report, following the method of Ricci and Smith [Phys. Rev. ST Accel. Beams 3, 032801 (2000PRABFM1098-440210.1103/PhysRevSTAB.3.032801], we investigate the measurement of the longitudinal bunch profile of an ultrashort electron bunch produced by these FELs. We show that this method can be applied in a straightforward manner at x-ray FEL facilities such as the Linac Coherent Light Source by slightly adjusting the second bunch compressor followed by running the bunch on an rf zero-crossing phase of the final linac. We find that the linac wakefield strongly perturbs the measurement, and through analysis show that it can be compensated in a simple way. We demonstrate the effectiveness of this method and wakefield compensation through numerical simulations, including effects of coherent synchrotron radiation and longitudinal space charge. When used in conjunction with a high-resolution electron spectrometer, this method potentially reveals the temporal profile of the electron beam down to the femtosecond and subfemotsecond scale.

  5. Design of a 10 MeV normal conducting CW proton linac based on equidistant multi-gap CH cavities

    CERN Document Server

    Li, Zhihui

    2014-01-01

    The continue wave (CW) high current proton linac has wide applications as the front end of the high power proton machines. The low energy part is the most difficult one and there is no widely accepted solution yet. Based on the analysis of the focusing properties of the CW low energy proton linac, a 10 MeV low energy normal conducting proton linac based on equidistant seven-gap Cross-bar H-type (CH) cavities is proposed. The linac is composed of ten 7-gap CH cavities and the transverse focusing is maintained by the quadrupole doublets located between cavities. The total length of the linac is less than 6 meters and the average acceleration gradient is about 1.2 MeV/m. The electromagnetic properties of the cavities are investigated by Microwave Studio. At the nominal acceleration gradient the maximum surface electric field in the cavities is less than 1.3 times Kilpatrick limit, and the Ohmic loss of each cavity is less than 35 kW. The multi-particle beam dynamics simulations are performed with the help of the...

  6. Design of a 10 MeV normal conducting CW proton linac based on equidistant multi-gap CH cavities

    Science.gov (United States)

    Li, Zhi-Hui

    2015-09-01

    Continuous wave (CW) high current proton linacs have wide applications as the front end of high power proton machines. The low energy part of such a linac is the most difficult and there is currently no widely accepted solution. Based on the analysis of the focusing properties of the CW low energy proton linac, a 10 MeV low energy normal conducting proton linac based on equidistant seven-gap Cross-bar H-type (CH) cavities is proposed. The linac is composed of ten 7-gap CH cavities and the transverse focusing is maintained by quadrupole doublets located between the cavities. The total length of the linac is less than 6 meters and the average acceleration gradient is about 1.2 MeV/m. The electromagnetic properties of the cavities are investigated by Microwave Studio. At the nominal acceleration gradient the maximum surface electric field in the cavities is less than 1.3 times the Kilpatrick limit, and the Ohmic loss of each cavity is less than 35 kW. Multi-particle beam dynamics simulations are performed with Tracewin code, and the results show that the beam dynamics of the linac are quite stable, the linac has the capability to accelerate up to 30 mA beam with acceptable dynamics behavior. Supported by National Natural Science Foundation of China (11375122, 91126003)

  7. Deflecting RF cavity design for a recirculating linac based facility for ultrafast X-ray science (LUX)

    Energy Technology Data Exchange (ETDEWEB)

    Li, Derun; Corlett, J.N.

    2003-05-01

    We report on superconducting deflecting RF cavity designs for a Recirculating Linac Based Facility for Ultrafast X-ray Science (LUX) at Lawrence Berkeley National Laboratory. The deflecting cavities operate in the lowest dipole mode and are required to produce a temporal correlation within flat electron bunches, as needed for x-ray compression in crystal optics. Deflecting voltage of up to 8.5-MV is required at 3.9-GHz. We present a 7-cell cavity design in this paper. Seven such cavities are required to generate the 8.5 MV deflecting voltage. Longitudinal and transverse impedance from LOM (lower order mode) and HOM (higher order mode) are simulated using the MAFIA code. Short-range and long-range wakefield excited through these impedances are calculated. Beam loading effects of the deflecting mode and LOM modes are estimated. Q values of the LOM monopole modes in the cavity may need to be damped to be below 10{sup 4}-10{sup 5} levels in order to maintain the required energy spread.

  8. ITS Version 6 : the integrated TIGER series of coupled electron/photon Monte Carlo transport codes.

    Energy Technology Data Exchange (ETDEWEB)

    Franke, Brian Claude; Kensek, Ronald Patrick; Laub, Thomas William

    2008-04-01

    ITS is a powerful and user-friendly software package permitting state-of-the-art Monte Carlo solution of lineartime-independent coupled electron/photon radiation transport problems, with or without the presence of macroscopic electric and magnetic fields of arbitrary spatial dependence. Our goal has been to simultaneously maximize operational simplicity and physical accuracy. Through a set of preprocessor directives, the user selects one of the many ITS codes. The ease with which the makefile system is applied combines with an input scheme based on order-independent descriptive keywords that makes maximum use of defaults and internal error checking to provide experimentalists and theorists alike with a method for the routine but rigorous solution of sophisticated radiation transport problems. Physical rigor is provided by employing accurate cross sections, sampling distributions, and physical models for describing the production and transport of the electron/photon cascade from 1.0 GeV down to 1.0 keV. The availability of source code permits the more sophisticated user to tailor the codes to specific applications and to extend the capabilities of the codes to more complex applications. Version 6, the latest version of ITS, contains (1) improvements to the ITS 5.0 codes, and (2) conversion to Fortran 90. The general user friendliness of the software has been enhanced through memory allocation to reduce the need for users to modify and recompile the code.

  9. Novel layered two-dimensional semiconductors as the building blocks for nano-electronic/photonic systems

    Science.gov (United States)

    Su, Guoxiong; De, Debtanu; Hadjiev, Viktor G.; Peng, Haibing

    2014-06-01

    Layered two-dimensional (2D) semiconductors beyond graphene have been emerging as potential building blocks for the next-generation electronic/photonic applications. Representative metal chalcogenides, including the widely studied MoS2, possess similar layered crystal structures with weak interaction between adjacent layers, thus allowing the formation of stable thin-layer crystals with thickness down to a few or even single atomic layer. Other important chalcogenides, involving earth-abundant and environment-friendly materials desirable for sustainable applications, include SnS2 (band gap: 2.1 eV) and SnS (band gap: 1.1 eV). So far, commonly adopted for research purpose are mechanical and liquid exfoliation methods for creating thin layers of such 2D semiconductors. Most recently, chemical vapor deposition (CVD) was attracting significant attention as a practical method for producing thin films or crystal grains of MoS2. However, critical yet still absent is an effective experimental approach for controlling the positions of thin crystal grains of layered 2D semiconductors during the CVD process. Here we report the controlled CVD synthesis of thin crystal arrays of representative layered semiconductors (including SnS2 and SnS) at designed locations on chip, promising large-scale optoelectronic applications. Our work opens a window for future practical applications of layered 2D semiconductors in integrated nano-electronic/photonic systems.

  10. On the robustness of VMAT-SABR treatment plans against isocentre positioning uncertainties.

    Science.gov (United States)

    Stroom, Joep; Vieira, Sandra; Mateus, Dalila; Greco, Carlo; Fogliata, Antonella; Nicolini, Giorgia; Clivio, Alessandro; Vanetti, Eugenio; Cozzi, Luca

    2014-09-05

    To appraise the robustness of VMAT dose distributions against uncertainties in the positioning of the patients when single fraction SABRT treatments are planned. A set of 18 patients (8 lung, 5 brain, 5 spinal or para-spinal) treated with VMAT in a single fraction of 24Gy were retrospectively analyzed. All approved plans were re-calculated by applying shifts to the isocentre of ±0.5, ±1, ±1.5, ±2 and ±3 mm along the primary X, Y and Z axes. Dose calculations were performed with the AAA and the Acuros engines. Quantitative analysis of DVH was performed on a total of 36 references (18 patients with AAA, 18 with Acuros) and 1080 re-calculated plans to measure the potential degree of deterioration of the plans according to the simulated errors. The dose to the CTV was essentially not affected by the isocenter shifts in all cases. Concerning PTV, The main impact was observed on the near-to-minimum dose D99%. No relevant impact was observed on organs at risk in the case of lung patients. In the case of patients treated in the spinal or para-spinal region, the near-to-maximum dose to the spine showed, in the worst scenario, referring to Acuros calculation, a potential average increase of 0.3Gy with a maximum of 1.9Gy (from 10.3 to 12.2 Gy) or 18%. This was partially mitigated to 12% with 1 mm and to 5% with 0.5 mm shifts. The study showed that shifts in the position of the isocenter as large as 3 mm tend to have modest impacts on the quality of the VMAT plans, scored by means of conventional DVH parameters. From the data shown, the VMAT approach should be considered adequately robust for single fraction SABR.

  11. Non isocentric film-based intracavitary brachytherapy planning in cervical cancer: a retrospective dosimetric analysis with CT planning.

    Science.gov (United States)

    Tyagi, Kirti; Mukundan, Hari; Mukherjee, Deboleena; Semwal, Manoj; Sarin, Arti

    2012-09-01

    To compare intracavitary brachytherapy dose estimation for organs at risk (bladder and rectum) based on semi-orthogonal reconstruction of radiographs on non-isocentric X-ray unit and Computed Tomography (CT) - based volumetric planning in cervical cancer. Bladder and rectal points as per International Commission on Radiation Units and Measurements (ICRU) report 38, were retrospectively evaluated on 15 high dose rate intracavitary brachytherapy applications for cervical cancer cases. With the same source configuration as obtained during planning on radiographs performed on a non-isocentric X-ray unit, the mean doses to 2cc of most irradiated part of bladder and rectum were computed by CT planning and these estimates were compared with the doses at ICRU bladder and rectal points. The mean ICRU point dose for bladder was 3.08 Gy (1.9-5.9 Gy) and mean dose to 2 cc (D2cc) bladder was 6.91 Gy (2.9-12.2 Gy). ICRU rectal dose was 3.8 Gy (2.4-4.45 Gy) and was comparable with D2cc rectum dose 4.2 Gy (2.8-5.9 Gy). Comparison of mean total dose (ICRU point vs. D2cc) for each patient was found to be significantly different for bladder (p = 0.000), but not for rectum (p = 0.08). On comparison of ICRU point based planning with volumetric planning on CT, it was found that bladder doses were underestimated by the film based method. However, the rectal doses were found to be similar to the D2cc doses. The results with non isocentric film based treatment planning were similar to the existing literature on orthogonal film based simulator planning.

  12. Space applications of the MITS electron-photon Monte Carlo transport code system

    Energy Technology Data Exchange (ETDEWEB)

    Kensek, R.P.; Lorence, L.J.; Halbleib, J.A. [Sandia National Labs., Albuquerque, NM (United States); Morel, J.E. [Los Alamos National Lab., NM (United States)

    1996-07-01

    The MITS multigroup/continuous-energy electron-photon Monte Carlo transport code system has matured to the point that it is capable of addressing more realistic three-dimensional adjoint applications. It is first employed to efficiently predict point doses as a function of source energy for simple three-dimensional experimental geometries exposed to simulated uniform isotropic planar sources of monoenergetic electrons up to 4.0 MeV. Results are in very good agreement with experimental data. It is then used to efficiently simulate dose to a detector in a subsystem of a GPS satellite due to its natural electron environment, employing a relatively complex model of the satellite. The capability for survivability analysis of space systems is demonstrated, and results are obtained with and without variance reduction.

  13. Union od fields in the treatment of breast with above using mono-isocentric technique, without hemi fields or table turns; Union de campos en tratamientos de mama con supra mediante tecnica monoisocentrica, sin hemicampos y sin giros de mesa

    Energy Technology Data Exchange (ETDEWEB)

    Saez Beltran, F.; Benito Bejarano, M. A.; Saez Beltran, M.

    2013-07-01

    The technical of treatments for breast with supra by mono isocentric technical, without twists isocentric table, and sliding fields that do not have to be hemi fields, allows a better bond between the tangential fields and supraclavicular fields. In addition, It also allows a greater size and tangential fields to display the whole area of treatment in the portal imaging system. (Author)

  14. Multi-isocentric 4π volumetric-modulated arc therapy approach for head and neck cancer.

    Science.gov (United States)

    Subramanian, Vallinayagam Shanmuga; Subramani, Vellaiyan; Chilukuri, Srinivas; Kathirvel, Murugesan; Arun, Gandhi; Swamy, Shanmugam Thirumalai; Subramanian, Kala; Fogliata, Antonella; Cozzi, Luca

    2017-09-01

    To explore the feasibility of multi-isocentric 4π volumetric-modulated arc therapy (MI4π-VMAT) for the complex targets of head and neck cancers. Twenty-five previously treated patients of HNC underwent re-planning to improve the dose distributions with either coplanar VMAT technique (CP-VMAT) or noncoplanar MI4π-VMAT plans. The latter, involving 3-6 noncoplanar arcs and 2-3 isocenters were re-optimized using the same priorities and objectives. Dosimetric comparison on standard metrics from dose-volume histograms was performed to appraise relative merits of the two techniques. Pretreatment quality assurance was performed with IMRT phantoms to assess deliverability and accuracy of the MI4π-VMAT plans. The gamma agreement index (GAI) analysis with criteria of 3 mm distance to agreement (DTA) and 3% dose difference (DD) was applied. CP-VMAT and MI4π-VMAT plans achieved the same degree of coverage for all target volumes related to near-to-minimum and near-to-maximum doses. MI4π-VΜΑΤ plans resulted in an improved sparing of organs at risk. The average mean dose reduction to the parotids, larynx, oral cavity, and pharyngeal muscles were 3 Gy, 4 Gy, 5 Gy, and 4.3 Gy, respectively. The average maximum dose reduction to the brain stem, spinal cord, and oral cavity was 6.0 Gy, 3.8 Gy, and 2.4 Gy. Pretreatment QA results showed that plans can be reliably delivered with mean gamma agreement index of 97.0 ± 1.1%. MI4π-VMAT plans allowed to decrease the dose-volume-metrics for relevant OAR and results are reliable from a dosimetric standpoint. Early clinical experience has begun and future studies will report treatment outcome. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  15. Measurement of cone beam CT coincidence with megavoltage isocentre and image sharpness using the QUASAR Penta-Guide phantom.

    Science.gov (United States)

    Sykes, J R; Lindsay, R; Dean, C J; Brettle, D S; Magee, D R; Thwaites, D I

    2008-10-07

    For image-guided radiotherapy (IGRT) systems based on cone beam CT (CBCT) integrated into a linear accelerator, the reproducible alignment of imager to x-ray source is critical to the registration of both the x-ray-volumetric image with the megavoltage (MV) beam isocentre and image sharpness. An enhanced method of determining the CBCT to MV isocentre alignment using the QUASAR Penta-Guide phantom was developed which improved both precision and accuracy. This was benchmarked against our existing method which used software and a ball-bearing (BB) phantom provided by Elekta. Additionally, a method of measuring an image sharpness metric (MTF(50)) from the edge response function of a spherical air cavity within the Penta-Guide phantom was developed and its sensitivity was tested by simulating misalignments of the kV imager. Reproducibility testing of the enhanced Penta-Guide method demonstrated a systematic error of <0.2 mm when compared to the BB method with near equivalent random error (s=0.15 mm). The mean MTF(50) for five measurements was 0.278+/-0.004 lp mm(-1) with no applied misalignment. Simulated misalignments exhibited a clear peak in the MTF(50) enabling misalignments greater than 0.4 mm to be detected. The Penta-Guide phantom can be used to precisely measure CBCT-MV coincidence and image sharpness on CBCT-IGRT systems.

  16. Potential role for LINAC-based stereotactic radiosurgery for the treatment of 5 or more radioresistant melanoma brain metastases.

    Science.gov (United States)

    Frakes, Jessica M; Figura, Nicholas B; Ahmed, Kamran A; Juan, Tzu-Hua; Patel, Neha; Latifi, Kujtim; Sarangkasiri, Siriporn; Strom, Tobin J; Chinnaiyan, Prakash; Rao, Nikhil G; Etame, Arnold B

    2015-11-01

    Linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) is a treatment option for patients with melanoma in whom brain metastases have developed. Very limited data are available on treating patients with ≥5 lesions. The authors sought to determine the effectiveness of SRS in patients with ≥5 melanoma brain metastases. A retrospective analysis of metastatic melanoma treated with SRS in a single treatment session for ≥5 lesions was performed. Magnetic resonance imaging studies were reviewed post-SRS to evaluate local control (LC). Disease progression on imaging was defined using the 2009 Response Evaluation Criteria in Solid Tumors (RECIST). Survival curves were calculated from the date of brain metastases diagnosis or the date of SRS by using the Kaplan-Meier (KM) method. Univariate and multivariate analysis (UVA and MVA, respectively) were performed using the Cox proportional-hazards model. The authors identified 149 metastatic brain lesions treated in 28 patients. The median patient age was 60.5 years (range 38-83 years), and the majority of patients (24 [85.7%]) had extracranial metastases. Four patients (14.3%) had received previous whole-brain radiotherapy (WBRT), and 11 (39.3%) had undergone previous SRS. The median planning target volume (PTV) was 0.34 cm3 (range 0.01-12.5 cm3). Median follow-up was 6.3 months (range 1-46 months). At the time of treatment, 7% of patients were categorized as recursive partitioning analysis (RPA) Class I, 89% as RPA Class II, and 4% as RPA Class III. The rate of local failure was 11.4%. Kaplan-Meier LC estimates at 6 and 12 months were 91.3% and 82.2%, respectively. A PTV volume≥0.34 cm3 was a significant predictor of local failure on UVA (HR 16.1, 95% CI 3.2-292.6, ptreatment. The RPA class was a significant predictor of KM OS estimates from the date of treatment (p=0.02). Patients who did not receive WBRT after SRS treatment had decreased OS on MVA (HR 3.5, 95% CI 1.1-12.0, p=0.03), and patients who did not

  17. Monolithic Ge-on-Si lasers for large-scale electronic-photonic integration

    Science.gov (United States)

    Liu, Jifeng; Kimerling, Lionel C.; Michel, Jurgen

    2012-09-01

    A silicon-based monolithic laser source has long been envisioned as a key enabling component for large-scale electronic-photonic integration in future generations of high-performance computation and communication systems. In this paper we present a comprehensive review on the development of monolithic Ge-on-Si lasers for this application. Starting with a historical review of light emission from the direct gap transition of Ge dating back to the 1960s, we focus on the rapid progress in band-engineered Ge-on-Si lasers in the past five years after a nearly 30-year gap in this research field. Ge has become an interesting candidate for active devices in Si photonics in the past decade due to its pseudo-direct gap behavior and compatibility with Si complementary metal oxide semiconductor (CMOS) processing. In 2007, we proposed combing tensile strain with n-type doping to compensate the energy difference between the direct and indirect band gap of Ge, thereby achieving net optical gain for CMOS-compatible diode lasers. Here we systematically present theoretical modeling, material growth methods, spontaneous emission, optical gain, and lasing under optical and electrical pumping from band-engineered Ge-on-Si, culminated by recently demonstrated electrically pumped Ge-on-Si lasers with >1 mW output in the communication wavelength window of 1500-1700 nm. The broad gain spectrum enables on-chip wavelength division multiplexing. A unique feature of band-engineered pseudo-direct gap Ge light emitters is that the emission intensity increases with temperature, exactly opposite to conventional direct gap semiconductor light-emitting devices. This extraordinary thermal anti-quenching behavior greatly facilitates monolithic integration on Si microchips where temperatures can reach up to 80 °C during operation. The same band-engineering approach can be extended to other pseudo-direct gap semiconductors, allowing us to achieve efficient light emission at wavelengths previously

  18. Metrology and quality of radiation therapy dosimetry of electron, photon and epithermal neutron beams

    Energy Technology Data Exchange (ETDEWEB)

    Kosunen, A

    1999-08-01

    In radiation therapy using electron and photon beams the dosimetry chain consists of several sequential phases starting by the realisation of the dose quantity in the Primary Standard Dosimetry Laboratory and ending to the calculation of the dose to a patient. A similar procedure can be described for the dosimetry of epithermal neutron beams in boron neutron capture therapy (BNCT). To achieve the required accuracy of the dose delivered to a patient the quality of all steps in the dosimetry procedure has to be considered. This work is focused on two items in the dosimetry chains: the determination of the dose in the reference conditions and the evaluation of the accuracy of dose calculation methods. The issues investigated and discussed in detail are: a)the calibration methods of plane parallel ionisation chambers used in electron beam dosimetry, (b) the specification of the critical dosimetric parameter i.e. the ratio of stopping powers for water to air, (S I ?){sup water} {sub air}, in photon beams, (c) the feasibility of the twin ionization chamber technique for dosimetry in epithermal neutron beams applied to BNCT and (d) the determination accuracy of the calculated dose distributions in phantoms in electron, photon, and epithermal neutron beams. The results demonstrate that up to a 3% improvement in the consistency of dose determinations in electron beams is achieved by the calibration of plane parallel ionisation chambers in high energy electron beams instead of calibrations in {sup 60}Co gamma beams. In photon beam dosimetry (S I ?){sup water} {sub air} can be determined with an accuracy of 0.2% using the percentage dose at the 10 cm depth, %dd(10), as a beam specifier. The use of %odd(10) requires the elimination of the electron contamination in the photon beam. By a twin ionisation chamber technique the gamma dose can be determined with uncertainty of 6% (1 standard deviation) and the total neutron dose with an uncertainty of 15 to 20% (1 standard deviation

  19. Utilization of optical tracking to validate a software-driven isocentric approach to robotic couch movements for proton radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Hsi, Wen C., E-mail: Wen.Hsi@Mclaren.org, E-mail: Wenchien.hsi@sphic.org.cn; Zeidan, Omar A., E-mail: omar.zeidan@orlandohealth.com [ProCure Proton Therapy Center, Oklahoma City, Oklahoma 73142 (United States); Law, Aaron; Schreuder, Andreas N., E-mail: niek.schreuder@provisionhp.com [ProCure Training and Development Center, Bloomington, Indiana 47404 (United States)

    2014-08-15

    Purpose: An optical tracking and positioning system (OTPS) was developed to validate the software-driven isocentric (SDI) approach to control the six-degrees-of-freedom movement of a robotic couch. Methods: The SDI approach to movements rotating around a predefined isocenter, referred to as a GeoIso, instead of a mechanical pivot point was developed by the robot automation industry. With robotic couch-sag corrections for weight load in a traditional SDI approach, movements could be accurately executed for a GeoIso located within a 500 mm cubic volume on the couch for treatments. The accuracy of SDI movement was investigated using the OTPS. The GeoIso was assumed to align with the proton beam isocenter (RadIso) for gantry at the reference angle. However, the misalignment between GeoIso and RadIso was quantitatively investigated by measuring the displacements at various couch angles for a target placed at the RadIso at an initial couch angle. When circular target displacements occur on a plane, a relative isocenter shift (RIS) correction could be applied in the SDI movement to minimize target displacements. Target displacements at a fixed gantry angle without and with RIS correction were measured for 12 robotic couches. Target displacements for various gantry angles were performed on three couches in gantry rooms to study the gantry-induced RadIso shift. The RIS correction can also be applied for the RadIso shift. A new SDI approach incorporating the RIS correction with the couch sag is described in this study. In parallel, the accuracy of SDI translation movements for various weight loads of patients on the couch was investigated during positioning of patients for proton prostate treatments. Results: For a fixed gantry angle, measured target displacements without RIS correction for couch rotations in the horizontal plane varied from 4 to 20 mm. However, measured displacements perpendicular to couch rotation plane were about 2 mm for all couches. Extracted

  20. ITS version 5.0 : the integrated TIGER series of coupled electron/photon Monte Carlo transport codes.

    Energy Technology Data Exchange (ETDEWEB)

    Franke, Brian Claude; Kensek, Ronald Patrick; Laub, Thomas William

    2004-06-01

    ITS is a powerful and user-friendly software package permitting state of the art Monte Carlo solution of linear time-independent couple electron/photon radiation transport problems, with or without the presence of macroscopic electric and magnetic fields of arbitrary spatial dependence. Our goal has been to simultaneously maximize operational simplicity and physical accuracy. Through a set of preprocessor directives, the user selects one of the many ITS codes. The ease with which the makefile system is applied combines with an input scheme based on order-independent descriptive keywords that makes maximum use of defaults and internal error checking to provide experimentalists and theorists alike with a method for the routine but rigorous solution of sophisticated radiation transport problems. Physical rigor is provided by employing accurate cross sections, sampling distributions, and physical models for describing the production and transport of the electron/photon cascade from 1.0 GeV down to 1.0 keV. The availability of source code permits the more sophisticated user to tailor the codes to specific applications and to extend the capabilities of the codes to more complex applications. Version 5.0, the latest version of ITS, contains (1) improvements to the ITS 3.0 continuous-energy codes, (2)multigroup codes with adjoint transport capabilities, and (3) parallel implementations of all ITS codes. Moreover the general user friendliness of the software has been enhanced through increased internal error checking and improved code portability.

  1. Laser-Driven Very High Energy Electron/Photon Beam Radiation Therapy in Conjunction with a Robotic System

    Directory of Open Access Journals (Sweden)

    Kazuhisa Nakajima

    2014-12-01

    Full Text Available We present a new external-beam radiation therapy system using very-high-energy (VHE electron/photon beams generated by a centimeter-scale laser plasma accelerator built in a robotic system. Most types of external-beam radiation therapy are delivered using a machine called a medical linear accelerator driven by radio frequency (RF power amplifiers, producing electron beams with an energy range of 6–20 MeV, in conjunction with modern radiation therapy technologies for effective shaping of three-dimensional dose distributions and spatially accurate dose delivery with imaging verification. However, the limited penetration depth and low quality of the transverse penumbra at such electron beams delivered from the present RF linear accelerators prevent the implementation of advanced modalities in current cancer treatments. These drawbacks can be overcome if the electron energy is increased to above 50 MeV. To overcome the disadvantages of the present RF-based medical accelerators, harnessing recent advancement of laser-driven plasma accelerators capable of producing 1-GeV electron beams in a 1-cm gas cell, we propose a new embodiment of the external-beam radiation therapy robotic system delivering very high-energy electron/photon beams with an energy of 50–250 MeV; it is more compact, less expensive, and has a simpler operation and higher performance in comparison with the current radiation therapy system.

  2. A deterministic electron, photon, proton and heavy ion transport suite for the study of the Jovian moon Europa

    Science.gov (United States)

    Badavi, Francis F.; Blattnig, Steve R.; Atwell, William; Nealy, John E.; Norman, Ryan B.

    2011-02-01

    A Langley research center (LaRC) developed deterministic suite of radiation transport codes describing the propagation of electron, photon, proton and heavy ion in condensed media is used to simulate the exposure from the spectral distribution of the aforementioned particles in the Jovian radiation environment. Based on the measurements by the Galileo probe (1995-2003) heavy ion counter (HIC), the choice of trapped heavy ions is limited to carbon, oxygen and sulfur (COS). The deterministic particle transport suite consists of a coupled electron photon algorithm (CEPTRN) and a coupled light heavy ion algorithm (HZETRN). The primary purpose for the development of the transport suite is to provide a means to the spacecraft design community to rapidly perform numerous repetitive calculations essential for electron, photon, proton and heavy ion exposure assessment in a complex space structure. In this paper, the reference radiation environment of the Galilean satellite Europa is used as a representative boundary condition to show the capabilities of the transport suite. While the transport suite can directly access the output electron and proton spectra of the Jovian environment as generated by the jet propulsion laboratory (JPL) Galileo interim radiation electron (GIRE) model of 2003; for the sake of relevance to the upcoming Europa Jupiter system mission (EJSM), the JPL provided Europa mission fluence spectrum, is used to produce the corresponding depth dose curve in silicon behind a default aluminum shield of 100 mils (˜0.7 g/cm2). The transport suite can also accept a geometry describing ray traced thickness file from a computer aided design (CAD) package and calculate the total ionizing dose (TID) at a specific target point within the interior of the vehicle. In that regard, using a low fidelity CAD model of the Galileo probe generated by the authors, the transport suite was verified versus Monte Carlo (MC) simulation for orbits JOI-J35 of the Galileo probe

  3. Multi-Beam Interference Advances and Applications: Nano-Electronics, Photonic Crystals, Metamaterials, Subwavelength Structures, Optical Trapping, and Biomedical Structures

    Directory of Open Access Journals (Sweden)

    Thomas K. Gaylord

    2011-06-01

    Full Text Available Research in recent years has greatly advanced the understanding and capabilities of multi-beam interference (MBI. With this technology it is now possible to generate a wide range of one-, two-, and three-dimensional periodic optical-intensity distributions at the micro- and nano-scale over a large length/area/volume. These patterns may be used directly or recorded in photo-sensitive materials using multi-beam interference lithography (MBIL to accomplish subwavelength patterning. Advances in MBI and MBIL and a very wide range of applications areas including nano-electronics, photonic crystals, metamaterials, subwavelength structures, optical trapping, and biomedical structures are reviewed and put into a unified perspective.

  4. Flat-panel cone-beam CT on a mobile isocentric C-arm for image-guided brachytherapy

    Science.gov (United States)

    Jaffray, David A.; Siewerdsen, Jeffrey H.; Edmundson, Gregory K.; Wong, John W.; Martinez, Alvaro A.

    2002-05-01

    Flat-panel imager (FPI) based cone-beam computed tomography (CBCT) is a strong candidate technology for intraoperative imaging in image-guided procedures such as brachytherapy. The soft-tissue imaging performance and potential navigational utility have been investigated using a computer-controlled benchtop system. These early results have driven the development of an isocentric C-arm for intraoperative FPI-CBCT, capable of collecting 94 projections over 180 degrees in 110 seconds. The C-arm system employs a large-area FPI with 400 micron pixel pitch and Gd2O2S:Tb scintillator. Image acquisition, processing and reconstruction are orchestrated under a single Windows-based application. Reconstruction is performed by a modified Feldkamp algorithm implemented on a high-speed reconstruction engine. Non-idealities in the source and detector trajectories during orbital motion has been quantified and tested for stability. Cone-beam CT imaging performance was tested through both quantitative and qualitative methods. The system MTF was measured using a wire phantom and demonstrated frequency pass out to 0.6 mm-1. Voxel noise was measured at 2.7 percent in a uniform 12 cm diameter water bath. Anatomical phantoms were employed for qualitative evaluation of the imaging performance. Images of an anaesthetized rabbit demonstrated the capacity of the system to discern soft-tissue structures within a living subject while offering sub-millimeter spatial resolution. The dose delivered in each of the imaging procedures was estimated from in-air exposure measurements to be approximately 0.1 cGy. Imaging studies of an anthropomorphic prostate phantom were performed with and without radioactive seeds. Soft-tissue imaging performance and seed detection appear to satisfy the imaging and navigation requirements for image-guided brachytherapy. These investigations advance the development and evaluation of such technology for image-guided surgical procedures, including brachytherapy

  5. SU-F-T-647: Linac-Based Stereotactic Radiosurgery (SRS) in the Treatment of Trigeminal Neuralgia: Detailed Description of SRS Procedural Technique and Reported Clinical Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Pokhrel, D; Sood, S; Badkul, R; Jiang, H; Stepp, T; Camarata, P; Wang, F [University of Kansas Hospital, Kansas City, KS (United States)

    2016-06-15

    Purpose: SRS is an effective non-invasive alternative treatment modality with minimal-toxicity used to treat patients with medically/surgically refractory trigeminal neuralgia root(TNR) or those who may not tolerate surgical intervention. We present our linac-based SRS procedure for TNR treatment and simultaneously report our clinical outcomes. Methods: Twenty-eight TNR-patients treated with frame-based SRS at our institution (2009–2015) with a single-fraction point-dose of 60-80Gy to TNR were included in this IRB-approved study. Experienced neurosurgeon and radiation oncologist delineated the TNR on 1.0mm thin 3D-FIESTA-MRI that was co-registered with 0.7mm thin planning-CT. Treatment plans were generated in iPlan (BrainLAB) with a 4-mm diameter cone using 79 arcs with differential-weighting for Novalis-TX 6MV-SRS(1000MU/min) beam and optimized to minimize brainstem dose. Winston-Lutz test was performed before each treatment delivery with sub-millimeter isocenter accuracy. Quality assurance of frame placement was maintained by helmet-bobble-measurement before simulation-CT and before patient setup at treatment couch. OBI-CBCT scan was performed for patient setup verification without applying shifts. On clinical follow up, treatment response was assessed using Barrow Neurological Institute Pain Intensity Score(BNI-score:I–V). Results: 26/28 TNR-patients (16-males/10-females) who were treated with following single-fraction point-dose to isocenter: 80Gy(n=22),75Gy(n=1),70Gy(n=2) and 60Gy(n=1, re-treatment) were followed up. Median follow-up interval was 8.5-months (ranged:1–48.5months). Median age was 70-yr (ranged:43–93-yr). Right/left TNR ratio was 15/11. Delivered total # of average MUs was 19034±1204. Average beam-on-time: 19.0±1.3min. Brainstem max-dose and dose to 0.5cc were 13.3±2.4Gy (ranged:8.1–16.5Gy) and 3.6±0.4Gy (ranged:3.0–4.9Gy). On average, max-dose to optic-apparatus was ≤1.2Gy. Mean value of max-dose to eyes/lens was 0.26Gy/0.11Gy

  6. SU-E-T-567: A Three-Field Mono-Isocentric Inverse Treatment Planning Method for the Patients with Larger Breasts

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, T; Marina, O; Chen, P; Teahan, M; Liu, Q; Benedetti, L [William Beaumont Hospital, Royal Oak, MI (United States)

    2014-06-01

    Purpose: The purpose of this study is to develop a three-field monoisocentric inverse breast treatment planning technique without the use of half-beam block. Methods: Conventional three-field breast treatment with supraclavicular half-beam blocked requires two isocenters when the breast is too large to be contained within half-beam. The inferior border of the supraclavicular field and superior borders of the breast fields are matched on patient's skin with the light field. This method causes a large dose variation in the matching region due to daily setup uncertainties and requires a longer treatment setup time. We developed a three-field mono-isocentric planning method for the treatment of larger breasts. The three fields share the same isocenter located in the breast. Beam matching is achieved by rotating collimator, couch and gantry. Furthermore, we employed a mixed open-IMRT inverse optimization method to improve dose uniformity and coverage. Results: Perfect geometric beam matching was achieved by rotating couch, collimator and gantry together. Treatment setup time was significantly reduced without light-field matching during treatment deliveries. Inverse mixed open-IMRT optimization method achieved better dose uniformity and PTV coverage while keeping sufficient air flash to compensate setup and breast shape changes in daily treatments. Conclusion: By eliminating light field matching, the three-field mono-isocentric treatment method can significantly reduce setup time and uncertainty for large breast patients. Plan quality is further improved by inverse IMRT planning.

  7. SU-E-T-355: A Comparative Study of Robotic and Linac-Based Stereotactitc Body Radiation Therapy for Lumbar Spinal Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Bossart, E; Monterroso, M; Couto, M; Ly, B; Mihaylov, I [UniversityMiami, Miami, FL (United States)

    2014-06-01

    Purpose: Dosimetrically compare CyberKnife (CK) and linac-based (LB) stereotactic body radiotherapy (SBRT) plans for lumbar spine. Methods: Ten patient plans with lumbar spine tumors treated with CK were selected and retrospectively optimized using three techniques: CK, volumetric modulated arc (VMAT, three arcs), and 9-field-intensity modulated radiotherapy (IMRT). For the LB plans, the target volume was expanded by 1mm to accommodate additional uncertainty in patient positioning. All plans were optimized to a prescription dose of 27Gy in 3 fractions covering 90% of the PTV. If the dose constraints to the cauda equina (cauda) were not met, the prescription dose was lowered to 24Gy. Parameters evaluated included Paddick Conformity-Index (CI) and Gradient-Index (GI). A two-tailed paired t-test was used to establish statistically significant differences in cauda doses. Results: Target volumes for LB plans were on average 38% larger. In terms of the indices, the closer the index values to unity the steeper the dose falloff and the higher the dose conformity to the target. The results showed that LB plans were in general statistically superior to CK plans. The IMRT plan showed the best average gradient index of 2.995, with VMAT and CK GI values of 3.699 and 5.476, respectively. Similarly, the same trend occurs with the average CI results: 0.821, 0.814, and 0.758, corresponding to IMRT, VMAT, and CK. Notably, in one CK plan the target dose was reduced to 24Gy to meet cauda constraints. Additionally, there was a statistically significant dose difference for the cauda between the CK and LB plans. Conclusion: This study demonstrates that LB plans for lumbar spine SBRT can be as effective or even better than CK plans. Despite the expansion of the target volume, the LB plans did not demonstrate dosimetric inferiority. The LB plans Resultin 2-to-3 fold decrease of treatment time.

  8. Comparison of Isocentric C-Arm 3-Dimensional Navigation and Conventional Fluoroscopy for Percutaneous Retrograde Screwing for Anterior Column Fracture of Acetabulum: An Observational Study.

    Science.gov (United States)

    He, Jiliang; Tan, Guoqing; Zhou, Dongsheng; Sun, Liang; Li, Qinghu; Yang, Yongliang; Liu, Ping

    2016-01-01

    Percutaneous screw insertion for minimally displaced or reducible acetabular fracture using x-ray fluoroscopy and computer-assisted navigation system has been advocated by some authors. The purpose of this study was to compare intraoperative conditions and clinical results between isocentric C-arm 3-dimensional (Iso-C 3D) fluoroscopy and conventional fluoroscopy for percutaneous retrograde screwing of acetabular anterior column fracture.A prospective cohort study was conducted. A total of 22 patients were assigned to 2 different groups: 10 patients in the Iso-C 3D navigation group and 12 patients in the conventional group. The operative time, fluoroscopic time, time of screw insertion, blood loss, and accuracy were analyzed between the 2 groups.There were significant differences in operative time, screw insertion time, fluoroscopy time, and mean blood loss between the 2 groups. Totally 2 of 12 (16.7%) screws were misplaced in the conventional fluoroscopy group, and all 10 screws were in safe zones in the navigation group. Percutaneous screw fixation using the Iso-C 3D computer-assisted navigation system significantly reduced the intraoperative fluoroscopy time and blood loss in percutaneous screwing for acetabular anterior column fracture.The Iso-C 3D computer-assisted navigation system provided a reliable and effective method for percutaneous screw insertion in acetabular anterior column fractures compared to conventional fluoroscopy.

  9. Proposal to Build an Electron-Photon Facility at NAL and to Measure Photon Scattering at High Energies

    Energy Technology Data Exchange (ETDEWEB)

    Dorfan, D.E.; Flatte, S.M.; Heusch, C.A.; Luxton, G.; del Papa, C.; Seiden, A.

    1971-07-18

    a photon beam becoming available at NAL at an early date. We propose to participate actively, as we have done in the past, in the design and implementation of the electron-photon facility, and to perform at the earliest possible date an experiment which will yield information on three vitally important processes in photon scattering: (1) measurement of the total hadronic photon cross-section on nucleons and nuclei; (2) elastic photon scattering (proton compton effect); (3) inelastic photon scattering; as a byproduct, we will have data on yields of {pi}{sup 0}, {eta}{sup 0}, X{sup 0}, {omega}{sup 0}, ... through their 2{gamma} or 3{gamma} decay modes. The set of experiments proposed here, together with experiments proposed by other groups, will tell us not only about the structure of the hadrons, but about the behavior of the photon at high energies. It has the virtue of being accessible through one basic, well-integrated set of experimental equipment, as detailed. The facility as well as the detection apparatus is being developed in consultation with the MIT - Canada collaboration. Equipment may be shared, and some of the running may be able to proceed compatibly. The success of this program will depend crucially on the design of appropriate halo-free beam lines; and on the early design and testing of optimal shower detection equipment - for both energy measurement and localization (or trajectory reconstruction). Our group has considerable experience in both these areas. Shower detectors are being built in Santa Cruz and can be conveniently tested at nearby SLAC. Also, a beam designed by our group, which we feel is flexible, economical, and viable, is included in this proposal. The essential feature of our proposal is this: Our shower detection equipment can be tested and calibrated in available SLAC beams before the first turn-on of the NAL photon beam, and will be ready at that time. While information on the longitudinal and lateral shower spread can be

  10. Thermally controlled coupling of a rolled-up microtube integrated with a waveguide on a silicon electronic-photonic integrated circuit.

    Science.gov (United States)

    Zhong, Qiuhang; Tian, Zhaobing; Veerasubramanian, Venkat; Dastjerdi, M Hadi Tavakoli; Mi, Zetian; Plant, David V

    2014-05-01

    We report on the first experimental demonstration of the thermal control of coupling strength between a rolled-up microtube and a waveguide on a silicon electronic-photonic integrated circuit. The microtubes are fabricated by selectively releasing a coherently strained GaAs/InGaAs heterostructure bilayer. The fabricated microtubes are then integrated with silicon waveguides using an abruptly tapered fiber probe. By tuning the gap between the microtube and the waveguide using localized heaters, the microtube-waveguide evanescent coupling is effectively controlled. With heating, the extinction ratio of a microtube whispering-gallery mode changes over an 18 dB range, while the resonant wavelength remains approximately unchanged. Utilizing this dynamic thermal tuning effect, we realize coupling modulation of the microtube integrated with the silicon waveguide at 2 kHz with a heater voltage swing of 0-6 V.

  11. ITS version 5.0 :the integrated TIGER series of coupled electron/Photon monte carlo transport codes with CAD geometry.

    Energy Technology Data Exchange (ETDEWEB)

    Franke, Brian Claude; Kensek, Ronald Patrick; Laub, Thomas William

    2005-09-01

    ITS is a powerful and user-friendly software package permitting state-of-the-art Monte Carlo solution of linear time-independent coupled electron/photon radiation transport problems, with or without the presence of macroscopic electric and magnetic fields of arbitrary spatial dependence. Our goal has been to simultaneously maximize operational simplicity and physical accuracy. Through a set of preprocessor directives, the user selects one of the many ITS codes. The ease with which the makefile system is applied combines with an input scheme based on order-independent descriptive keywords that makes maximum use of defaults and internal error checking to provide experimentalists and theorists alike with a method for the routine but rigorous solution of sophisticated radiation transport problems. Physical rigor is provided by employing accurate cross sections, sampling distributions, and physical models for describing the production and transport of the electron/photon cascade from 1.0 GeV down to 1.0 keV. The availability of source code permits the more sophisticated user to tailor the codes to specific applications and to extend the capabilities of the codes to more complex applications. Version 5.0, the latest version of ITS, contains (1) improvements to the ITS 3.0 continuous-energy codes, (2) multigroup codes with adjoint transport capabilities, (3) parallel implementations of all ITS codes, (4) a general purpose geometry engine for linking with CAD or other geometry formats, and (5) the Cholla facet geometry library. Moreover, the general user friendliness of the software has been enhanced through increased internal error checking and improved code portability.

  12. Isocentric color saliency in images

    NARCIS (Netherlands)

    Valenti, R.; Sebe, N.; Gevers, T.

    2009-01-01

    In this paper we propose a novel computational method to infer visual saliency in images. The computational method is based on the idea that salient objects should have local characteristics that are different than the rest of the scene, being edges, color or shape, and that these characteristics ca

  13. Polymers for electronic & photonic application

    CERN Document Server

    Wong, C P

    2013-01-01

    The most recent advances in the use of polymeric materials by the electronic industry can be found in Polymers for Electronic and Photonic Applications. This bookprovides in-depth coverage of photoresis for micro-lithography, microelectronic encapsulants and packaging, insulators, dielectrics for multichip packaging,electronic and photonic applications of polymeric materials, among many other topics. Intended for engineers and scientists who design, process, and manufacturemicroelectronic components, this book will also prove useful for hybrid and systems packaging managers who want to be info

  14. High-quality Linac-based Stereotactic Body Radiation Therapy with Flattening Filter Free Beams and Volumetric Modulated Arc Therapy for Low-Intermediate Risk Prostate Cancer. A Mono-institutional Experience with 90 Patients.

    Science.gov (United States)

    D'Agostino, G; Franzese, C; De Rose, F; Franceschini, D; Comito, T; Villa, E; Alongi, F; Liardo, R; Tomatis, S; Navarria, P; Mancosu, P; Reggiori, G; Cozzi, L; Scorsetti, M

    2016-12-01

    The aim of this phase II study was to evaluate the efficacy and toxicity of stereotactic body radiotherapy in patients with low or intermediate risk prostate cancer. Biopsy-confirmed prostate cancer patients were enrolled, provided that they had the following characteristics: initial prostate-specific antigen (PSA) ≤ 20 ng/ml, Gleason Score free beams. Toxicity was recorded according to CTCAE criteria v4.0. Biochemical failure was calculated according to the Phoenix definition. The Expanded Prostate Cancer Index Composite questionnaire was used to record health-related quality of life. Between December 2011 and March 2015, 90 patients were enrolled (53 low risk, 37 intermediate risk). The median age was 71 years (range 48-82). In total, 58 (64.5%) of the patients had Gleason Score=6, the remaining had Gleason Score=7.The median initial PSA was 6.9 ng/ml (range 2.7-17.0). Acute toxicity was mild, with 32.2 patients presenting grade 1 urinary toxicity and 32.2% of patients presenting grade 2 urinary toxicity, mainly represented by urgency, dysuria and stranguria. Rectal grade 1 toxicity was found in 15.5% of patients, whereas grade 2 toxicity was recorded in 6.6% of patients. Regarding late toxicity, grade 1 proctitis was recorded in 11.1% of patients and grade 1 urinary in 38.8%; only two events of grade 2 urinary toxicity were observed (transient urethral stenosis, resolved by a 24 h catheterisation). At a median follow-up of 27 months (6-62 months) only two intermediate risk patients experienced a biochemical failure. Health-related quality of life revealed a slight worsening in all the domains during treatment, with a return to baseline 3 months after treatment. Stereotactic body radiotherapy delivered using linac-based flattening filter free volumetric modulated arc radiotherapy in low and intermediate risk prostate cancer patients is associated with mild toxicity profiles and good patient-reported quality of life. Copyright © 2016 The Royal College of

  15. Run 1 Legacy Performance : electrons/photons

    CERN Document Server

    Damazio, D O; The ATLAS collaboration

    2014-01-01

    In this talk, the run 1 legacy performance of the electron and photon reconstruction and identification in the ATLAS and CMS experiments will be described, as well as the associated systematic uncertainties. The two speakers should try to enlight the differences of performances between the two experiments, and explain what worked better/worse than planned, as well as the lessons for the run 2.

  16. LHCb calorimeter electronics. Photon identification. Calorimeter calibration

    CERN Document Server

    Machefert, F

    LHCb is one of the four large experiments installed on the LHC accelerator ring. The aim of the detector is to precisely measure CP violation observables and rare decays in the B meson sector. The calorimeter system of LHCb is made of four sub-systems: the scintillating pad detector, the preshower, the electromagnetic (ECAL) and hadronic (HCAL) calorimeters. It is essential to reconstruct B decays, to efficiently trigger on interesting events and to identify electrons and photons. After a review of the LHCb detector sub-systems, the first part of this document describes the calorimeter electronics. First, the front-end electronics in charge of measuring the ECAL and HCAL signals from the photomultipliers is presented, then the following section is an overview of the control card of the four calorimeters. The chapters three and four concern the test software of this electronics and the technological choices making it tolerant to radiations in the LHCb cavern environment. The measurements performed to ensure th...

  17. Accurate eye center location through invariant isocentric patterns

    NARCIS (Netherlands)

    Valenti, R.; Gevers, T.

    2012-01-01

    Locating the center of the eyes allows for valuable information to be captured and used in a wide range of applications. Accurate eye center location can be determined using commercial eye-gaze trackers, but additional constraints and expensive hardware make these existing solutions unattractive and

  18. Electron, photons, and molecules: Storing energy from light

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.R. [Argonne National Laboratory, IL (United States)

    1996-09-01

    Molecular charge separation has important potential for photochemical energy storage. Its efficiency can be enhanced by principals which maximize the rates of the electron transfer steps which separate charge and minimize those which recombine high-energy charge pairs to lose stored energy. Dramatic scientific progress in understanding these principals has occurred since the founding of DOE and its predecessor agency ERDA. While additional knowledge in needed in broad areas of molecular electron transfer, some key areas of knowledge hold particular promise for the possibility of moving this area from science toward technology capable of contributing to the nation`s energy economy.

  19. Quantum Kinetic Theory and Applications Electrons, Photons, Phonons

    CERN Document Server

    Vasko, Fedir T

    2006-01-01

    This lecture-style monograph is addressed to several categories of readers. First, it will be useful for graduate students studying theory. Second, the topics covered should be interesting for postgraduate students of various specializations. Third, the researchers who want to understand the background of modern theoretical issues in more detail can find a number of useful results here. The phenomena covered involve kinetics of electron, phonon, and photon systems in solids. The dynamical properties and interactions of electrons, phonons, and photons are briefly described in Chapter 1. Further, in Chapters 2-8, the authors present the main theoretical methods: linear response theory, various kinetic equations for the quasiparticles under consideration, and diagram technique. The presentation of the key approaches is always accompanied by solutions of concrete problems to illustrate ways to apply the theory. The remaining chapters are devoted to various manifestations of quantum transport in solids. The choice...

  20. Wide Bandgap Semiconductor Nanowires for Electronic, Photonic and Sensing Devices

    Science.gov (United States)

    2012-01-05

    exciton emission at 3.24 eV. Also, the ZnO nanorods can be integrated with AlGaN/ GaN HEMT sensors by incorporating the nano-rods on the HEMT gate sensing...area, the total sensing area increases significantly. The conventional AlGaN/ GaN HEMT detects the ambient changes through the “gate sensing area...glucose interaction to the AlGaN/ GaN HEMT . With such low detection limit, it is possible to dilute ɘ.1 micro-liter of EBC in 100-200 micro-liter

  1. Scattering problems involving electrons, photons, and Dirac fermions

    NARCIS (Netherlands)

    Snyman, Izak

    2008-01-01

    The theoretical foundation for the work reported here is provided by Landauer's scattering theory of electron transport. The three main ingredients of a scattering problem are (1) a set of reservoirs that emit and absorb particles, (2) the particles themselves, that propagate as waves between the re

  2. LDRD project 151362 : low energy electron-photon transport.

    Energy Technology Data Exchange (ETDEWEB)

    Kensek, Ronald Patrick; Hjalmarson, Harold Paul; Magyar, Rudolph J.; Bondi, Robert James; Crawford, Martin James

    2013-09-01

    At sufficiently high energies, the wavelengths of electrons and photons are short enough to only interact with one atom at time, leading to the popular %E2%80%9Cindependent-atom approximation%E2%80%9D. We attempted to incorporate atomic structure in the generation of cross sections (which embody the modeled physics) to improve transport at lower energies. We document our successes and failures. This was a three-year LDRD project. The core team consisted of a radiation-transport expert, a solid-state physicist, and two DFT experts.

  3. MEMS-Electronic-Photonic Heterogeneous Integrated FMCW Ladar Source

    Science.gov (United States)

    2015-12-18

    bumps  on  the  backside  of  the  silicon  photonics   wafer  are  matching  the  pattern  on  the... wafer -­‐to-­‐ wafer  variation  of  the  bond   bumps  was  manifested  in  varying  bond   bump  quality.  2   Wafers ...presented  good  bond   bump  quality,  while  two   wafers  presented

  4. Comparative analyses of linac and Gamma Knife radiosurgery for trigeminal neuralgia treatments

    Science.gov (United States)

    Ma, L.; Kwok, Y.; Chin, L. S.; Yu, C.; Regine, W. F.

    2005-11-01

    Dedicated linac-based radiosurgery has been reported for trigeminal neuralgia treatments. In this study, we investigated the dose fall-off characteristics and setup error tolerance of linac-based radiosurgery as compared with standard Gamma Knife radiosurgery. In order to minimize the errors from different treatment planning calculations, consistent imaging registration, dose calculation and dose volume analysis methods were developed and implemented for both Gamma Knife and linac-based treatments. Intra-arc setup errors were incorporated into the treatment planning process of linac-based deliveries. The effects of intra-arc setup errors with increasing number of arcs were studied and benchmarked against Gamma Knife deliveries with and without plugging patterns. Our studies found equivalent dose fall-off properties between Gamma Knife and linac-based radiosurgery given a sufficient number of arcs (>7) and small intra-arc errors (<0.5 mm) were satisfied for linac-based deliveries. Increasing the number of arcs significantly decreased the variations in the dose fall-off curve at the low isodose region (e.g. from 40% to 10%) and also improved dose uniformity at the high isodose region (e.g. from 70% to 90%). As the number of arcs increased, the effects of intra-arc setup errors on the dose fall-off curves decreased. Increasing the number of arcs also reduced the integral dose to the distal normal brain tissues. In conclusion, linac-based radiosurgery produces equivalent dose fall-off characteristics to Gamma Knife radiosurgery with a high number of arcs. However, one must note the increased treatment time for a large number of arcs and isocentre accuracies.

  5. Comparative analyses of linac and Gamma Knife radiosurgery for trigeminal neuralgia treatments

    Energy Technology Data Exchange (ETDEWEB)

    Ma, L; Kwok, Y; Chin, L S; Yu, C; Regine, W F [University of Maryland School of Medicine, Baltimore, MD 21201 (United States)

    2005-11-21

    Dedicated linac-based radiosurgery has been reported for trigeminal neuralgia treatments. In this study, we investigated the dose fall-off characteristics and setup error tolerance of linac-based radiosurgery as compared with standard Gamma Knife radiosurgery. In order to minimize the errors from different treatment planning calculations, consistent imaging registration, dose calculation and dose volume analysis methods were developed and implemented for both Gamma Knife and linac-based treatments. Intra-arc setup errors were incorporated into the treatment planning process of linac-based deliveries. The effects of intra-arc setup errors with increasing number of arcs were studied and benchmarked against Gamma Knife deliveries with and without plugging patterns. Our studies found equivalent dose fall-off properties between Gamma Knife and linac-based radiosurgery given a sufficient number of arcs (>7) and small intra-arc errors (<0.5 mm) were satisfied for linac-based deliveries. Increasing the number of arcs significantly decreased the variations in the dose fall-off curve at the low isodose region (e.g. from 40% to 10%) and also improved dose uniformity at the high isodose region (e.g. from 70% to 90%). As the number of arcs increased, the effects of intra-arc setup errors on the dose fall-off curves decreased. Increasing the number of arcs also reduced the integral dose to the distal normal brain tissues. In conclusion, linac-based radiosurgery produces equivalent dose fall-off characteristics to Gamma Knife radiosurgery with a high number of arcs. However, one must note the increased treatment time for a large number of arcs and isocentre accuracies.

  6. Clinical results of LINAC-based stereotactic radiosurgery for pituitary adenoma

    Energy Technology Data Exchange (ETDEWEB)

    Muramatsu, Julia; Yoshida, Masanori; Shioura, Hiroki; Kawamura, Yasutaka; Ito, Harumi; Takeuchi, Hiroaki; Kubota, Toshihiko [Fukui Medical Univ., Matsuoka (Japan); Maruyama, Ichiro [The Wakasa Wan Energy Research Center, Tsuruga, Fukui (Japan)

    2003-05-01

    We retrospectively evaluated our clinical results of stereotactic radiosurgery (SRS) for pituitary adenoma. Between 1995 and 2000, 13 patients were treated with SRS for pituitary adenoma. In all cases, the tumors had already been surgically resected. The adenomas were functional in 5 and non-functional in 8 patients. The median follow-up period was 30 months. SRS was performed with the use of a dedicated stereotactic 10-MV linear accelerator (LINAC). The median dose to the tumor margin was 15 Gy. The dose to the optic apparatus was limited to less than 8 Gy. MR images of 12 patients revealed tumor complete response (CR) in one case and partial response (PR) in 9 cases; in the remaining two patients, tumor size decreased by less than 50%. There was no recognizable regrowth of any of the tumors. In two of four GH-secreting adenomas, hormonal overproduction normalized, while the other two showed reduced hormonal production. One PRL-secreting adenoma did not respond. Reduction of visual acuity and field was seen in one patient. This patient also had a brain infarction. None of the patients developed brain radionecrosis or radiation-induced hypopituitarism. Although further studies based on greater numbers of cases and longer follow-up periods are needed, our results suggest that SRS seems to be a safe, effective treatment for pituitary adenoma. (author)

  7. High Repetition Rate, LINAC-based Nuclear Resonance Fluorescence FY 2009 Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Mathew Kinlaw; Scott Watson; James Johnson; Alan Hunt; Heather Seipel; Edward Reedy

    2009-10-01

    Nuclear Resonance Fluorescence (NRF), which is possible for nuclei with atomic numbers greater than helium (Z=2), occurs when a nuclear level is excited by resonant absorption of a photon and subsequently decays by reemission of a photon. The excited nuclear states can become readily populated, provided the incident photon’s energy is within the Doppler-broadened width of the energy level being excited. Utilizing continuous energy photon spectra, as is characteristic of a bremsstrahlung photon beam, as the inspection source, ensures that at least some fraction of the impinging beam will contribute to the population of the excited energy levels in the material of interest. Upon de-excitation, either to the ground state or to a lower-energy excited state, the emitted fluorescence photon’s energy will correspond to the energy difference between the excited state and the state to which it decays. As each isotope inherently contains unique nuclear energy levels, the NRF states for each isotope are also unique. By exploiting this phenomenon, NRF photon detection provides a well-defined signature for identifying the presence of individual nuclear species. This report summarizes the second year (Fiscal Year [FY] 2009) of a collaborative research effort between Idaho National Laboratory, Idaho State University’s Idaho Accelerator Center, and Pacific Northwest National Laboratory. This effort focused on continuing to assess and optimize NRF-based detection techniques utilizing a slightly modified, commercially available, pulsed medical electron accelerator.

  8. SU-E-T-536: LINAC-Based Single Isocenter Frameless SRT for Brain Metastases

    Energy Technology Data Exchange (ETDEWEB)

    Liu, B; Zhang, L; Rigor, N; Kim, J [City of Hope Foundation, CA (United States)

    2015-06-15

    Purpose: Single-isocenter Stereotactic Radiotherapy of multiple brain metastases with Varian 21 IX LINAC, using Aktina Pinpoint system for patient setup. Methods: In 2014, five single-isocenter RapidArc SRT plans were delivered to five patients with 2 to 8 brain metastases using Varian 21 IX. Aktina Pinpoint system was used for setup and 2mm PTV margin were used. CBCT was acquired before and after the beam delivery. The prescription is 2100 cGy in 3 fractions. Eclipse planning system was used for treatment planning. Depending on the number of metastases and their locations, 1 to 5 coplanar or non coplanar arcs were used. Typically, 2 or 3 arcs are used. IMRT QAs were performed by comparing an A1SL ion chamber point dose measurement in solid water phantom to point dose of the plan; also, based on EPID measurement, 3D spatial dose was calculated using DosimetryCheck software package from MathResolutions Inc. The EPID system has an active area of 40cm by 30cm with 1024 by 768 photodiodes, which corresponds to a resolution of 0.4mm by 0.4mm pixel dimension. Results: for all the plans, at least 95% PTV coverage was achieved for full prescription dose, with plan normalization > 75%. RTOG conformity indices are less than 1.1 and Paddick gradient indices are less than 4.5. The distance from prescription IDL to 50% IDL increases as the number of metastases increases, and it ranges from 0.6mm to 0.8mm. Treatment time varies from 10mins to 30mins, depending on the number of arcs and if the arcs are coplanar. IMRT QA shows that the ion chamber measurement agree with the eclipse calculation within 3%, and 95% of the points passed Gamma, using 3% dose difference and 3mm DTA Conclusion: High quality single isocenter RapidArc SRT plan can be optimized and accurately delivered using Eclipse and Varian 21IX.

  9. S-band linac-based X-ray source with {pi}/2-mode electron linac

    Energy Technology Data Exchange (ETDEWEB)

    Deshpande, Abhay, E-mail: abhay@post.kek.jp [Department of Accelerator Science, School of High Energy Accelerator Science, Graduate University for Advanced Studies, Shonan International Village, Hayama, Miura, Kanagawa 240-0193 (Japan); Society for Applied Microwave Electronic Engineering and Research (SAMEER), R and D Laboratory of the Government of India, IIT Campus, Powai, Mumbai 400 076 (India); Araki, Sakae [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Dixit, Tanuja [Society for Applied Microwave Electronic Engineering and Research (SAMEER), R and D Laboratory of the Government of India, IIT Campus, Powai, Mumbai 400 076 (India); Fukuda, Masafumi [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Krishnan, R; Pethe, Sanjay [Society for Applied Microwave Electronic Engineering and Research (SAMEER), R and D Laboratory of the Government of India, IIT Campus, Powai, Mumbai 400 076 (India); Sakaue, Kazuyuki [Waseda University, Shinjuku-ku, Tokyo 169-8555 (Japan); Terunuma, Nobuhiro; Urakawa, Junji [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Washio, Masakazu [Waseda University, Shinjuku-ku, Tokyo 169-8555 (Japan)

    2011-05-01

    The activities with the compact X-ray source are attracting more attention, particularly for the applications of the source in medical fields. We propose the fabrication of a compact X-ray source using the SAMEER electron linear accelerator and the KEK laser undulator X-ray source (LUCX) technologies. The linac developed at SAMEER is a standing wave side-coupled S-band linac operating in the {pi}/2 mode. In the proposed system, a photocathode RF gun will inject bunches of electrons in the linac to accelerate and achieve a high-energy, low-emittance beam. This beam will then interact with the laser in the laser cavity to produce X-rays of a type well suited for various applications. The side-coupled structure will make the system more compact, and the {pi}/2 mode of operation will enable a high repetition rate operation, which will help to increase the X-ray yield.

  10. LUX — A Recirculating Linac-based Ultrafast X-ray Source

    Science.gov (United States)

    Corlett, J. N.; Barletta, W. A.; DeSantis, S.; Doolittle, L.; Fawley, W. M.; Green, M. A.; Heimann, P.; Leone, S. R.; Lidia, S.; Li, D.; Parmigiani, F.; Ratti, A.; Robinson, K.; Schoenlein, R.; Staples, J.; Wan, W.; Wells, R.; Wilcox, R.; Wolski, A.; Zholents, A.

    2004-05-01

    We describe the design of a proposed source of ultra-fast synchrotron radiation x-ray pulses based on a recirculating superconducting linac, with an integrated array of ultrafast laser systems. The source produces x-ray pulses with duration of 10-50 fs at a 10 kHz repetition rate, with tunability from EUV to hard x-ray regimes, and optimized for the study of ultra-fast dynamics. A high-brightness rf photocathode provides electron bunches. An injector linac accelerates the beam to the 100 MeV range, and is followed by four passes through a 700 MeV recirculating linac. Ultrafast hard x-ray pulses are obtained by a combination of electron bunch manipulation, transverse temporal correlation of the electrons, and x-ray pulse compression. EUV and soft x-ray pulses as short as 10 fs are generated in a harmonic-cascade free electron laser scheme. We describe the facility major systems and peformance.

  11. A recirculating linac based synchrotron light source for ultrafast x-ray science

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, J.N.; Barry, W.; Byrd, J.M.; DeSantis, S.; Heimann, P.; Lidia, S.; Li, D.; Rimmer, R.; Robinson, K.; Schoenlein, R.; Tanabe, J.; Wang, S.; Wan, W.; Wells, R.; Zholents, A.; Placidi, M.; Pirkl, W.

    2002-05-30

    LBNL is pursuing a multi-divisional initiative that has this year further developed design studies and the scientific program for a facility dedicated to the production of x-ray pulses with ultra-short time duration. Our proposed x-ray facility [1] has the short x-ray pulse length ({approx};60 fs FWHM) necessary to study very fast dynamics, high flux (approximately 1011 photons/sec/0.1 percentBW) to study weakly scattering systems, and tuneability over 1-10 keV photon energy. The photon production section of the machine accomodates seven 2m long undulators and six 2T field dipole magnets. The x-ray pulse repetition rate of 10 kHz is matched to studies of dynamical processes (initiated by ultra-short laser pulses) that typicaly have a long recovery time or are not generally cyclic or reversible and need time to allow relaxation, replacement, or flow of the sample. The technique for producing ultra-short x-ray pulses uses relatively long electron bunches to minimise high-peak-current collective effects, and the ultimate x-ray duration is achieved by a combination of bunch manipulation and optical compression.

  12. Feasibility study for a recirculating linac-based facility for femtosecond dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, J.N.; Barry, W.; Barletta, W.A.; Byrd, J.M.; DeSantis, S.; Doolittle, L.; Fawley, W.; Green, M.A.; Hartman, N.; Heimann, P.; Kairan, D.; Kujawski, E.; Li, D.; Lidia, S.; Luft, P.; McClure, R.; Parmigiani, F.; Petroff, Y.; Pirkl, W.; Placidi, M.; Reavill, D.; Reichel, I.; Rimmer, R.A.; Ratti, A.; Robinson, K.E.; Sannibale, F.; Schoenlein, R.; Staples, J.; Tanabe, J.; Truchlikova, D.; Wan, W.; Wang, S.; Wells, R.; Wolski, A.; Zholents, A.

    2002-12-21

    LBNL is pursuing design studies and the scientific program for a facility dedicated to the production of x-ray pulses with ultra-short time duration, for application in dynamical studies of processes in physics, biology, and chemistry. The proposed x-ray facility has the short x-ray pulse length ({approx}60 fs FWHM) necessary to study very fast dynamics, high flux (up to approximately 10E11 photons/sec/0.1 percentBW) to study weakly scattering systems, and tuneability over 1-12 keV photon energy. The hard x-ray photon production section of the machine accommodates seven 2-m long undulators. Design studies for longer wavelength sources, using high-gain harmonic generation, are in progress. The x-ray pulse repetition rate of 10 kHz is matched to studies of dynamical processes (initiated by ultra-short laser pulses) that typically have a long recovery time or are not generally cyclic or reversible and need time to allow relaxation, replacement, or flow of the sample. The technique for producing ultra-short x-ray pulses uses relatively long electron bunches to minimize high-peak-current collective effects, and the ultimate x-ray duration is achieved by a combination of bunch manipulation and optical compression. Synchronization of x-ray pulses to sample excitation signals is expected to be of order 50 - 100 fs. Techniques for making use of the recirculating geometry to provide beam-based signals from early passes through the machine are being studied.

  13. LUX - a recirculating linac-based facility for ultrafast X-ray science

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, J.N.; Barletta, W.A.; DeSantis, S.; Doolittle, L.; Fawley, W.M.; Heimann, P.; Leone, S.; Lidia, S.; Li, D.; Penn, G.; Ratti, A.; Reinsch, M.; Schoenlein, R.; Staples, J.; Stover, G.; Virostek, S.; Wan, W.; Wells, R.; Wilcox, R.; Wolski, A.; Wurtele, J.; Zholents, A.

    2004-06-29

    We present recent developments in design concepts for LUX - a source of ultra-short synchrotron radiation pulses based on a recirculating superconducting linac. The source produces high-flux x-ray pulses with duration of 100 fs or less at a 10 kHz repetition rate, optimized for the study of ultra-fast dynamics across many fields of science [1]. Cascaded harmonic generation in free-electron lasers (FEL's) produces coherent radiation in the VUV-soft x-ray regime, and a specialized technique is used to compress spontaneous emission for ultra-short-pulse photon production in the 1-10 keV range. High-brightness electron bunches of 2-3 mm-mrad emittance at 1 nC charge in 30 ps duration are produced in an rf photocathode gun and compressed to 3 ps duration following an injector linac, and recirculated three times through a 1 GeV main linac. In each return path, independently tunable harmonic cascades are inserted to produce seeded FEL radiation in selected photon energy ranges from approximately 20 eV with a single stage of harmonic generation, to 1 keV with a four-stage cascade. The lattice is designed to minimize emittance growth from effects such as coherent synchrotron radiation (CSR), and resistive wall wakefields. Timing jitter between pump lasers and x-ray pulses is minimized by use of a stable optical master oscillator, distributing timing signals over actively stabilized fiber-optic, phase-locking all lasers to the master oscillator, and generating all rf signals from the master oscillator. We describe technical developments including techniques for minimizing power dissipation in a high repetition rate rf photocathode gun, beam dynamics in two injector configurations, independently tunable beamlines for VUV and soft x-ray production by cascaded harmonic generation, a fast kicker design, timing systems for providing synchronization between experimental pump lasers and the x-ray pulse, and beamline design for maintaining nm-scale density modulation.

  14. Feasibility study for a recirculating linac-based facility for femtosecond dynamics

    CERN Document Server

    Corlett, J N; Barry, W; Byrd, J M; De Santis, S; Doolittle, L; Fawley, W; Green, M A; Hartman, N; Heimann, P A; Kairan, D; Kujawski, E; Li, D; Lidia, S M; Luft, P; McClure, R; Parmigiani, F; Petroff, Y; Pirkl, Werner; Placidi, Massimo; Ratti, A; Reavill, D; Reichel, I; Rimmer, R A; Robinson, K E; Sannibale, F; Schönlein, R W; Staples, J; Tanabe, J; Truchlikova, D; Wan, W; Wang, S; Wells, R; Wolski, A; Zholents, A

    2002-01-01

    LBNL is pursuing design studies and the scientific program for a facility of the production of x-ray pulses with ultra-short time duration, for application in dynamical studies of processes in physics, biology, and chemistry. The proposed x-ray facility has the short x-ray pulse length (approx 60 fs FWHM) necessary to study very fast dynamics, high flux (up to approximately 10E11 photons/sec/0.1 percentBW) to study weakly scattering systems, and tuneability over 1-12 keV photon energy. The hard x-ray photon production section of the machine accommodates seven 2-m long undulators. Design studies for longer wavelength sources, using high-gain harmonic generation, are in progress. The x-ray pulse repetition rate of 10 kHz is matched to studies of dynamical processes (initiated by ultra-short laser pulses) that typically have a long recovery time or are not generally cyclic or reversible and need time to allow relaxation, replacement, or flow of the sample. The technique for producing ultra-short x-ray pulses use...

  15. LUX - A recirculating linac-based ultrafast X-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, J.N.; Barletta, W.A.; DeSantis, S.; Doolittle, L.; Fawley, W.M.; Green, M.A.; Heimann, P.; Leone, S.R.; Lidia, S.; Li, D.; Parmigiani, F.; Ratti, A.; Robinson, K.; Schoenlein, R.; Staples, J.; Wan, W.; Wells, R.; Wilcox, R.; Wolski, A.; Zholents, A.

    2003-08-01

    We describe the design of a proposed source of ultra-fast synchrotron radiation x-ray pulses based on a recirculating superconducting linac, with an integrated array of ultrafast laser systems. The source produces x-ray pulses with duration of 10-50 fs at a 10 kHz repetition rate, with tunability from EUV to hard x-ray regimes, and optimized for the study of ultra-fast dynamics. A high-brightness rf photocathode provides electron bunches. An injector linac accelerates the beam to the 100 MeV range, and is followed by four passes through a 700 MeV recirculating linac. Ultrafast hard x-ray pulses are obtained by a combination of electron bunch manipulation, transverse temporal correlation of the electrons, and x-ray pulse compression. EUV and soft x-ray pulses as short as 10 fs are generated in a harmonic-cascade free electron laser scheme.

  16. Gamma Knife and LINAC-Based Stereotactic Treatments of Intracranial Targets: Dosimetric and Radiobiological Considerations

    Science.gov (United States)

    Kendall, Ethan Lee

    The scientific community is interested in furthering the understanding of shock wave structures in water, given its implications in a wide range of applications; from researching how shock waves penetrate unwanted body tissues to studying how humans respond to blast waves. Shock wave research on water has existed for over five decades. Previous studies have investigated the shock response of water at pressures ranging from 1 to 70 GPa using flyer plate experiments. This report differs from previously published experiments in that the water was loaded to shock pressures ranging from 0.36 to 0.70 GPa. The experiment also utilized tap water rather than distilled water as the test sample. Flyer plate experiments were conducted in the Shock Physics Laboratory at Marquette University to determine the structure of shock waves within water. A 12.7 mm bore gas gun fired a projectile made of copper, PMMA, or aluminum at a stationary target filled with tap water. Graphite break pins in a circuit determined the initial projectile velocity prior to coming into contact with the target. A Piezoelectric timing pin (PZT pin) at the front surface of the water sample determined the arrival of the leading wave and a Photon Doppler Velocimeter (PDV) measured particle velocity from the rear surface of the water sample. The experimental results were compared to simulated data from a Eulerian Hydrocode called CTH [1]. The experimental results differed from the simulated results with deviations believed to be from experimental equipment malfunctions. The main hypothesis being that the PZT pin false triggered, resulting in measured lower than expected shock velocities. The simulated results were compared to published data from various authors and was within range.

  17. Radiosurgery with photon beams; Physical aspects and adequacy of linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Podgorsak, E.B.; Pla, M.; Souhami, L. (McGill University, Montreal (Canada). Department of Radiation Oncology); Pike, G.B.; Olivier, A. (McGill University, Montreal (Canada). Department of Neurosurgery)

    1990-03-01

    The question of the adequacy of isocentric linear accelerators (linacs) for use in radiosurgery is addressed. The general physical requirements for radiosurgery, mainly a high spatial and numerical accuracy of dose delivery, reasonable treatment time, and low skin and leakage dose as well as cost considerations are examined. Various linac-based procedures are analyzed in view of their ability to meet these requirements and are contrasted with the clinically proven system of the Gamma unit. It is shown that the linac-based multiple converging arcs techniques and the dynamic rotation meet the stringent physical requirements on dose delivery and are thus viable alternatives to radiosurgery with the commercially available and dedicated Gamma unit. (author). 15 refs.; 2 figs.; 1 tab.

  18. EDITORIAL: Semiconductor nanotechnology: novel materials and devices for electronics, photonics and renewable energy applications Semiconductor nanotechnology: novel materials and devices for electronics, photonics and renewable energy applications

    Science.gov (United States)

    Goodnick, Stephen; Korkin, Anatoli; Krstic, Predrag; Mascher, Peter; Preston, John; Zaslavsky, Alex

    2010-04-01

    Electronic and photonic information technology and renewable energy alternatives, such as solar energy, fuel cells and batteries, have now reached an advanced stage in their development. Cost-effective improvements to current technological approaches have made great progress, but certain challenges remain. As feature sizes of the latest generations of electronic devices are approaching atomic dimensions, circuit speeds are now being limited by interconnect bottlenecks. This has prompted innovations such as the introduction of new materials into microelectronics manufacturing at an unprecedented rate and alternative technologies to silicon CMOS architectures. Despite the environmental impact of conventional fossil fuel consumption, the low cost of these energy sources has been a long-standing economic barrier to the development of alternative and more efficient renewable energy sources, fuel cells and batteries. In the face of mounting environmental concerns, interest in such alternative energy sources has grown. It is now widely accepted that nanotechnology offers potential solutions for securing future progress in information and energy technologies. The Canadian Semiconductor Technology Conference (CSTC) forum was established 25 years ago in Ottawa as an important symbol of the intrinsic strength of the Canadian semiconductor research and development community, and the Canadian semiconductor industry as a whole. In 2007, the 13th CSTC was held in Montreal, moving for the first time outside the national capital region. The first three meetings in the series of 'Nano and Giga Challenges in Electronics and Photonics'— NGCM2002 in Moscow, NGCM2004 in Krakow, and NGC2007 in Phoenix— were focused on interdisciplinary research from the fundamentals of materials science to the development of new system architectures. In 2009 NGC2009 and the 14th Canadian Semiconductor Technology Conference (CSTC2009) were held as a joint event, hosted by McMaster University (10-14 August, Hamilton, Ontario, Canada) and the scope was expanded to include renewable energy research and development. This special issue of Nanotechnology is devoted to a better understanding of the function and design of semiconductor devices that are relevant to information technology (both electronics and photonics based) and renewable energy applications. The papers contained in this special issue are selected from the NGC/CSTC2009 symposium. Among them is a report by Ray LaPierre from McMaster University and colleagues at the University of Waterloo in Canada on the ability to manipulate single spins in nanowire quantum bits. The paper also reports the development of a testbed of a few qubits for general quantum information processing tasks [1]. Lower cost and greater energy conversion efficiency compared with thin film devices have led to a high level of activity in nanowire research related to photovoltaic applications. This special issue also contains results from an impedance spectroscopy study of core-shell GaAs nanowires to throw light on the transport and recombination mechanisms relevant to solar cell research [2]. Information technology research and renewable energy sources are research areas of enormous public interest. This special issue addresses both theoretical and experimental achievements and provides a stimulating outlook for technological developments in these highly topical fields of research. References [1] Caram J, Sandoval C, Tirado M, Comedi D, Czaban J, Thompson D A and LaPierre R R 2101 Nanotechnology 21 134007 [2] Baugh J, Fung J S and LaPierre RR 2010 Nanotechnology 21 134018

  19. Robust Eye Center Localization through Face Alignment and Invariant Isocentric Patterns

    Science.gov (United States)

    Teng, Dongdong; Chen, Dihu; Tan, Hongzhou

    2015-01-01

    The localization of eye centers is a very useful cue for numerous applications like face recognition, facial expression recognition, and the early screening of neurological pathologies. Several methods relying on available light for accurate eye-center localization have been exploited. However, despite the considerable improvements that eye-center localization systems have undergone in recent years, only few of these developments deal with the challenges posed by the profile (non-frontal face). In this paper, we first use the explicit shape regression method to obtain the rough location of the eye centers. Because this method extracts global information from the human face, it is robust against any changes in the eye region. We exploit this robustness and utilize it as a constraint. To locate the eye centers accurately, we employ isophote curvature features, the accuracy of which has been demonstrated in a previous study. By applying these features, we obtain a series of eye-center locations which are candidates for the actual position of the eye-center. Among these locations, the estimated locations which minimize the reconstruction error between the two methods mentioned above are taken as the closest approximation for the eye centers locations. Therefore, we combine explicit shape regression and isophote curvature feature analysis to achieve robustness and accuracy, respectively. In practical experiments, we use BioID and FERET datasets to test our approach to obtaining an accurate eye-center location while retaining robustness against changes in scale and pose. In addition, we apply our method to non-frontal faces to test its robustness and accuracy, which are essential in gaze estimation but have seldom been mentioned in previous works. Through extensive experimentation, we show that the proposed method can achieve a significant improvement in accuracy and robustness over state-of-the-art techniques, with our method ranking second in terms of accuracy. According to our implementation on a PC with a Xeon 2.5Ghz CPU, the frame rate of the eye tracking process can achieve 38 Hz. PMID:26426929

  20. Robust Eye Center Localization through Face Alignment and Invariant Isocentric Patterns.

    Science.gov (United States)

    Pang, Zhiyong; Wei, Chuansheng; Teng, Dongdong; Chen, Dihu; Tan, Hongzhou

    2015-01-01

    The localization of eye centers is a very useful cue for numerous applications like face recognition, facial expression recognition, and the early screening of neurological pathologies. Several methods relying on available light for accurate eye-center localization have been exploited. However, despite the considerable improvements that eye-center localization systems have undergone in recent years, only few of these developments deal with the challenges posed by the profile (non-frontal face). In this paper, we first use the explicit shape regression method to obtain the rough location of the eye centers. Because this method extracts global information from the human face, it is robust against any changes in the eye region. We exploit this robustness and utilize it as a constraint. To locate the eye centers accurately, we employ isophote curvature features, the accuracy of which has been demonstrated in a previous study. By applying these features, we obtain a series of eye-center locations which are candidates for the actual position of the eye-center. Among these locations, the estimated locations which minimize the reconstruction error between the two methods mentioned above are taken as the closest approximation for the eye centers locations. Therefore, we combine explicit shape regression and isophote curvature feature analysis to achieve robustness and accuracy, respectively. In practical experiments, we use BioID and FERET datasets to test our approach to obtaining an accurate eye-center location while retaining robustness against changes in scale and pose. In addition, we apply our method to non-frontal faces to test its robustness and accuracy, which are essential in gaze estimation but have seldom been mentioned in previous works. Through extensive experimentation, we show that the proposed method can achieve a significant improvement in accuracy and robustness over state-of-the-art techniques, with our method ranking second in terms of accuracy. According to our implementation on a PC with a Xeon 2.5Ghz CPU, the frame rate of the eye tracking process can achieve 38 Hz.

  1. SU-E-J-48: Imaging Origin-Radiation Isocenter Coincidence for Linac-Based SRS with Novalis Tx

    Energy Technology Data Exchange (ETDEWEB)

    Geraghty, C; Workie, D; Hasson, B [Anne Arundel Medical Center, Annapolis, MD (United States)

    2015-06-15

    Purpose To implement and evaluate an image-based Winston-Lutz (WL) test to measure the displacement between ExacTrac imaging origin and radiation isocenter on a Novalis Tx system using RIT V6.2 software analysis tools. Displacement between imaging and radiation isocenters was tracked over time. The method was applied for cone-based and MLC-based WL tests. Methods The Brainlab Winston-Lutz phantom was aligned to room lasers. The ExacTrac imaging system was then used to detect the Winston- Lutz phantom and obtain the displacement between the center of the phantom and the imaging origin. EPID images of the phantom were obtained at various gantry and couch angles and analyzed with RIT calculating the phantom center to radiation isocenter displacement. The RIT and Exactrac displacements were combined to calculate the displacement between imaging origin and radiation isocenter. Results were tracked over time. Results Mean displacements between ExacTrac origin and radiation isocenter were: VRT: −0.1mm ± 0.3mm, LNG: 0.5mm ± 0.2mm, LAT: 0.2mm ± 0.2mm (vector magnitude of 0.7 ± 0.2mm). Radiation isocenter was characterized by the mean of the standard deviations of the WL phantom displacements: σVRT: 0.2mm, σLNG: 0.4mm, σLAT: 0.6mm. The linac couch base was serviced to reduce couch walkout. This reduced σLAT to 0.2mm. These measurements established a new baseline of radiation isocenter-imaging origin coincidence. Conclusion The image-based WL test has ensured submillimeter localization accuracy using the ExacTrac imaging system. Standard deviations of ExacTrac-radiation isocenter displacements indicate that average agreement within 0.3mm is possible in each axis. This WL test is a departure from the tradiational WL in that imaging origin/radiation isocenter agreement is the end goal not lasers/radiation isocenter.

  2. Estimation of Secondary Skin Cancer Risk Due To Electron Contamination in 18-MV LINAC-Based Prostate Radiotherapy

    Directory of Open Access Journals (Sweden)

    Seyed Mostafa Ghavami

    2016-12-01

    Full Text Available Introduction Accurate estimation of the skin-absorbed dose in external radiation therapy is essential to estimating the probability of secondary carcinogenesis induction Materials and Methods Electron contamination in prostate radiotherapy was investigated using the Monte Carlo (MC code calculation. In addition, field size dependence of the skin dose was assessed. Excess cancer risk induced by electron contamination was determined for the skin, surface dose, and prostate dose-volume histogram (DVH using MC calculation and analytical methods. Results MC calculations indicated that up to 80% of total electron contamination fluence was produced in the linear accelerator. At 5 mm below the skin surface, surface dose was estimated at 6%, 13%, 27%, and 38% for 5×5 cm2, 10×10 cm2, 20×20 cm2, and 40×40 cm2 field sizes, respectively. Relative dose at Dmax was calculated at 0.92% and 5.42% of the maximum dose for 5×5 cm2 and 40×40 cm2 field sizes, respectively. Excess absolute skin cancer risk was obtained at 2.96×10-4 (PY -1 for total 72 Gy. Differences in prostate and skin DVHs were 1.01% and 1.38%, respectively. Conclusion According to the results of this study, non-negligible doses are absorbed from contaminant electrons by the skin, which is associated with an excess risk of cancer induction.

  3. SU-E-T-54: A New Method for Optimizing Radiation Isocenter for Linac-Based SRS

    Energy Technology Data Exchange (ETDEWEB)

    Hancock, S [Southeast Missouri Hospital, Cape Girardeau, MO (United States); Hyer, D; Nixon, E [University Of Iowa, Iowa City, IA (United States)

    2015-06-15

    Purpose: To develop a new method to minimize deviation of linac x-ray beams from the centroid of the volumetric radiation isocenter for all combinations of gantry and table angle. Methods: A set of ball-bearing (Winston-Lutz) images was used to determine the gantry radiation isocenter as the midrange of deviation values. Deviations in the cross-plane direction were minimized by calibration of MLC leaf position offset, and by adjusting beam position steering for each energy. Special attention was also paid to matching the absolute position of isocenter across all energies by adjusting position steering in the gun-target axis. Displacement of table axis from the gantry isocenter, and recommended table axis adjustment for contemporary Elekta linacs, was also determined. Eight images were used to characterize the volumetric isocenter for the full range of gantry and table rotations available. Tabulation of deviation for each beam was used to test compliance with isocenter tolerance. Results: Four contemporary Elekta linacs were evaluated and the radius in the gun-target axis of the radiation isocenter was 0.5 to 0.7 mm. After beam steering adjustment, the radius in the cross-plane direction was typically 0.2 to 0.4 mm. Position matching between energies can be reduced to 0.28 mm. Maximum total deviation was 0.68 to 1.07 mm, depending primarily on the effect of systematic table axis wobble with rotation. Conclusion: This new method effectively facilitates minimization of deviation between beam center and target position. The test, which requires a few minutes to perform, can be easily incorporated into a routine machine QA program. A tighter radiation isocenter for contemporary Elekta linacs would require reducing the effect of gantry arm flex and/or table axis wobble that are the two main components of deviation from the designated isocenter point.

  4. A Compact 5 MeV S-Band Electron Linac Based X-Ray Source for Industrial Radiography

    CERN Document Server

    Auditore, Lucrezia; De Pasquale, Domenico; Emanuele, Umberto; Italiano, Antonio; Trifirò, Antonio; Trimarchi, Marina

    2005-01-01

    A compact and reliable X-ray source, based on a 5 MeV, 1 kW, S-band electron linac, has been set up at the Dipartimento di Fisica, Universit\\'a di Messina. This source, coupled with a GOS scintillator screen and a CCD camera, represents an innovative transportable system for industrial radiography and X-ray tomography. Optimization of the parameters influencing the e-gamma conversion and the X-ray beam characteristics have been studied by means of the MCNP-4C2 code. The converter choice is the result of the study of the e-gamma conversion performances for different materials and materials thicknesses. Also the converter position with respect to the linac exit window was studied. The chosen converter consists in a Ta-Cu target inserted close to the linac window. The Cu layer acts as a filter both on the electrons from the source and on the low energy X-rays. The X-ray beam angular profile was studied by means of GafChromic films with and without collimation. In the final source project, a collimation system pr...

  5. Development of mini linac-based positron source and an efficient positronium convertor for positively charged antihydrogen production

    Science.gov (United States)

    Muranaka, T.; Debu, P.; Dupré, P.; Liszkay, L.; Mansoulie, B.; Pérez, P.; Rey, J. M.; Ruiz, N.; Sacquin, Y.; Crivelli, P.; Gendotti, U.; Rubbia, A.

    2010-04-01

    We have installed in Saclay a facility for an intense positron source in November 2008. It is based on a compact 5.5 MeV electron linac connected to a reaction chamber with a tungsten target inside to produce positrons via pair production. The expected production rate for fast positrons is 5·1011 per second. The study of moderation of fast positrons and the construction of a slow positron trap are underway. In parallel, we have investigated an efficient positron-positronium convertor using porous silica materials. These studies are parts of a project to produce positively charged antihydrogen ions aiming to demonstrate the feasibility of a free fall antigravity measurement of neutral antihydrogen.

  6. Instrumentation and Beam Dynamics Study of Advanced Electron-Photon Facility in Indiana University

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Tianhuan [Indiana Univ., Bloomington, IN (United States)

    2011-08-01

    The Advanced eLectron-PHoton fAcility (ALPHA) is a compact electron accelerator under construction and being commissioned at the Indiana University Center for Exploration of Energy and Matter (CEEM). In this thesis, we have studied the refurbished Cooler Injector Synchrotron (CIS) RF cavity using both the transmission line model and SUPERFISH simulation. Both low power and high power RF measurements have been carried out to characterize the cavity. Considering the performance limit of ferrite, we have designed a new ferrite loaded, co-axial quarter wave like cavity with similar structure but a more suitable ferrite material. We have also designed a traveling wave stripline kicker for fast extraction by POISSON and Microwave Studio. The strips geometry is trimmed to maximize the uniformity of the kicking field and match the impedance of the power cables. The time response simulation shows the kicker is fast enough for machine operation. The pulsed power supply requirement has also been specified. For the beam diagnosis in the longitudinal direction, we use a wideband Wall Gap Monitor (WGM) served in CIS. With proper shielding and amplification to get good WGM signal, we have characterized the injected and extracted beam signal in single pass commissioning, and also verified the debunching effect of the ALPHA storage ring. A modulation-demodulation signal processing method is developed to measure the current and longitudinal profile of injected beam. By scanning the dipole strength in the injection line, we have reconstructed the tomography of the longitudinal phase space of the LINAC beam. In the accumulation mode, ALPHA will be operated under a low energy and high current condition, where intra beam scattering (IBS) becomes a dominant effect on the beam emittance. A self consistent simulation, including IBS effect, gas scattering and linear coupling, has been carried out to calculate the emittance of the stored beam.

  7. An empirical method for deriving RBE values associated with electrons, photons and radionuclides.

    Science.gov (United States)

    Bellamy, M; Puskin, J; Hertel, N; Eckerman, K

    2015-12-01

    There is substantial evidence to justify using relative biological effectiveness (RBE) values of >1 for low-energy electrons and photons. But, in the field of radiation protection, radiation associated with low linear energy transfer has been assigned a radiation weighting factor wR of 1. This value may be suitable for radiation protection but, for risk considerations, it is important to evaluate the potential elevated biological effectiveness of radiation to improve the quality of risk estimates. RBE values between 2 and 3 for tritium are implied by several experimental measurements. Additionally, elevated RBE values have been found for other similar low-energy radiation sources. In this work, RBE values are derived for electrons based upon the fractional deposition of absorbed dose of energies less than a few kiloelectron volts. Using this empirical method, RBE values were also derived for monoenergetic photons and 1070 radionuclides from ICRP Publication 107 for which photons and electrons are the primary emissions.

  8. Characterization of ancient Indian iron and entrapped slag inclusions using electron, photon and nuclear microprobes

    Indian Academy of Sciences (India)

    P Dillmann; R Balasubramaniam

    2001-06-01

    Compositional and structural information were obtained from an ancient 1600-year old Indian iron using microprobe techniques (EDS, XRD and PIXE). Several different local locations in the iron matrix and in the entrapped slag inclusions were analyzed. The P content of the metallic iron matrix was very heterogeneous. Lower P contents were observed in the regions near slag inclusions. This was correlated to the dephosphorization capacity of the slag. The crystallized phases identified in the slag inclusions were wüstite and fayalite. The compositions of the slag inclusions were relatively homogeneous.

  9. Nuclear physics with laser-electron-photons. Developments and perspectives at SPring-8

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, Mamoru [Osaka Univ., Ibaraki (Japan). Research Center for Nuclear Physics

    1998-03-01

    By the Compton scattering with ultraviolet laser beam using the 8 GeV electron beam of the SPring-8, the photon beam which is polarized by nearly 100% is obtained in 1-3.5 GeV region. The quark nuclear physics research at this facility is unique in the world, and it is expected that in the experiment at the SPring-8, the collision phenomena of polarized, high energy gamma-ray and the quarks in nucleons and the knockout phenomena of quarks are observed. Also the polarization experiment for clarifying ``the origin of nucleon spin`` has been proposed. Japan can stand at the top in the world in the research of quark nuclear physics with leptons. In the inverse Compton scattering using far infrared laser, the gamma-ray with good directionality of MeV range is obtained, and it will be applied widely to the research on E1 resonance and M1 excitation of atomic nuclei. In this report, the medium energy quark nuclear physics developed at the SPring-8 is outlined, and the nuclear physics which is expected to be developed when the high intensity, high polarization gamma-ray of about 10 MeV is generated is discussed. The detection of s, anti-s components in nucleons, research on baryon deformation and baryon spectra, verification of the Gerasimov, Drell-Hearn law of sum, meson structure, test of quark model by the photolysis of deuterons, dual Ginzburg Landau theory exploration, research on the mass and behavior of mesons in nuclear media are discussed. (K.I.)

  10. Nanotechnology and neuroscience nano-electronic, photonic and mechanical neuronal interfacing

    CERN Document Server

    Martiradonna, Luigi; Assad, John

    2014-01-01

     This book provides an overview of the different ways in which the “nano-world” can be beneficial for neuroscientists. The volume encompasses the latest developments in the field of micro- and nanotechnology applied to neuroscience, discussing technological approaches applied to both in-vitro and in-vivo experiments. A variety of different nanotechnologies are presented that include nanostructured electrodes and their electrical, mechanical and biochemical properties, active and passive 2D and 3D multi-electrode arrays (MEAs), nanoscale transistors for sub-cellular re-cordings and an overview on methods, tools and applications in optoge-netics. The book focuses specifically on fabrication strategies, to offer a compre-hensive guide for developing and applying micro- and nanostructured tools for neuroscientific applications. It is intended as a reference both for neuroscientists and nanotechnologists on the latest developments in neu-rotechnological tools.   • Provides readers with state-of-the-art in...

  11. Performance of electron, photon and muon triggers at the CMS High Level Trigger

    CERN Document Server

    Fernandez Perez Tomei, Thiago Rafael

    2015-01-01

    The trigger systems of the LHC detectors play a crucial role in determining the physics capabilities of the experiments. A reduction of several orders of magnitude of the event rate is needed to reach values compatible with the detector readout, offline storage and analysis capabilities. The CMS experiment has been designed with a two-level trigger system the Level 1 (L1) Trigger, implemented on custom-designed electronics, and the High Level Trigger (HLT), a streamlined version of the CMS reconstruction and analysis software running on a computer farm. Here we will present the design and performance of the main muon, electron and photon triggers, in view of the more challenging conditions for the LHC Run 2. For the muon case, we discuss the improvements in the isolation algorithm with the usage of Particle Flow techniques, which allow for better discrimination power between processes with prompt muons and the the effect of jets penetrating through the hadronic calorimeter into the muon chambers. For the ele...

  12. Instrumentation and beam dynamics study of advanced electron-photon facility in Indiana University

    Science.gov (United States)

    Luo, Tianhuan

    The Advanced eLectron-PHoton fAcility (ALPHA) is a compact electron accelerator under construction and being commissioned at the Indiana University Center for Exploration of Energy and Matter (CEEM). In this thesis, we have studied the refurbished Cooler Injector Synchrotron (CIS) RF cavity using both the transmission line model and SUPERFISH simulation. Both low power and high power RF measurements have been carried out to characterize the cavity. Considering the performance limit of ferrite, we have designed a new ferrite loaded, co-axial quarter wave like cavity with similar structure but a more suitable ferrite material. We have also designed a traveling wave stripline kicker for fast extraction by POISSON and Microwave Studio. The strips' geometry is trimmed to maximize the uniformity of the kicking field and match the impedance of the power cables. The time response simulation shows the kicker is fast enough for machine operation. The pulsed power supply requirement has also been speci ed. For the beam diagnosis in the longitudinal direction, we use a wideband Wall Gap Monitor (WGM) served in CIS. With proper shielding and amplification to get good WGM signal, we have characterized the injected and extracted beam signal in single pass commissioning, and also verified the debunching effect of the ALPHA storage ring. A modulation-demodulation signal processing method is developed to measure the current and longitudinal profile of injected beam. By scanning the dipole strength in the injection line, we have reconstructed the tomography of the longitudinal phase space of the LINAC beam. In the accumulation mode, ALPHA will be operated under a low energy and high current condition, where intra beam scattering (IBS) becomes a dominant effect on the beam emittance. A self consistent simulation, including IBS effect, gas scattering and linear coupling, has been carried out to calculate the emittance of the stored beam.

  13. Nuclear physics with laser-electron-photons. Developments and perspectives at SPring-8

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, Mamoru [Osaka Univ., Ibaraki (Japan). Research Center for Nuclear Physics

    1998-03-01

    By the Compton scattering with ultraviolet laser beam using the 8 GeV electron beam of the SPring-8, the photon beam which is polarized by nearly 100% is obtained in 1-3.5 GeV region. The quark nuclear physics research at this facility is unique in the world, and it is expected that in the experiment at the SPring-8, the collision phenomena of polarized, high energy gamma-ray and the quarks in nucleons and the knockout phenomena of quarks are observed. Also the polarization experiment for clarifying ``the origin of nucleon spin`` has been proposed. Japan can stand at the top in the world in the research of quark nuclear physics with leptons. In the inverse Compton scattering using far infrared laser, the gamma-ray with good directionality of MeV range is obtained, and it will be applied widely to the research on E1 resonance and M1 excitation of atomic nuclei. In this report, the medium energy quark nuclear physics developed at the SPring-8 is outlined, and the nuclear physics which is expected to be developed when the high intensity, high polarization gamma-ray of about 10 MeV is generated is discussed. The detection of s, anti-s components in nucleons, research on baryon deformation and baryon spectra, verification of the Gerasimov, Drell-Hearn law of sum, meson structure, test of quark model by the photolysis of deuterons, dual Ginzburg Landau theory exploration, research on the mass and behavior of mesons in nuclear media are discussed. (K.I.)

  14. 3D imaging with an isocentric mobile C-arm. Comparison of image quality with spiral CT

    Energy Technology Data Exchange (ETDEWEB)

    Kotsianos, Dorothea; Wirth, Stefan; Fischer, Tanja; Euler, Ekkehard; Rock, Clemens; Linsenmaier, Ulrich; Pfeifer, Klaus Juergen; Reiser, Maximilian [Departments of Radiology and Surgery, Klinikum der Universitaet Muenchen, Innenstadt, Nussbaumstrasse 20, 80336, Munchen (Germany)

    2004-09-01

    The purpose of this study was to evaluate the image quality of the new 3D imaging system (ISO-C-3D) for osteosyntheses of tibial condylar fractures in comparison with spiral CT (CT). Sixteen human cadaveric knees were examined with a C-arm 3D imaging system and spiral computed tomography. Various screws and plates of steel and titanium were used for osteosynthesis in these specimens. Image quality and clinical value of multiplanar (MP) reformatting of both methods were analyzed. In addition, five patients with tibial condylar fractures were examined for diagnosis and intra-operative control. The image quality of the C-arm 3D imaging system in the cadaveric study was rated as significantly worse than that of spiral CT with and without prostheses. After implantation of prostheses an increased incidence of artifacts was observed, but the diagnostic accuracy was not affected. Titanium implants caused the smallest number of artifacts. The image quality of ISO-C is inferior to CT, and metal artifacts were more prominent, but the clinical value was equal. ISO-C-3D can be useful in planning operative reconstructions and can verify the reconstruction of articular surfaces and the position of implants with diagnostic image quality. (orig.)

  15. 3D imaging with an isocentric mobile C-arm comparison of image quality with spiral CT.

    Science.gov (United States)

    Kotsianos, Dorothea; Wirth, Stefan; Fischer, Tanja; Euler, Ekkehard; Rock, Clemens; Linsenmaier, Ulrich; Pfeifer, Klaus Jürgen; Reiser, Maximilian

    2004-09-01

    The purpose of this study was to evaluate the image quality of the new 3D imaging system (ISO-C-3D) for osteosyntheses of tibial condylar fractures in comparison with spiral CT (CT). Sixteen human cadaveric knees were examined with a C-arm 3D imaging system and spiral computed tomography. Various screws and plates of steel and titanium were used for osteosynthesis in these specimens. Image quality and clinical value of multiplanar (MP) reformatting of both methods were analyzed. In addition, five patients with tibial condylar fractures were examined for diagnosis and intra-operative control. The image quality of the C-arm 3D imaging system in the cadaveric study was rated as significantly worse than that of spiral CT with and without prostheses. After implantation of prostheses an increased incidence of artifacts was observed, but the diagnostic accuracy was not affected. Titanium implants caused the smallest number of artifacts. The image quality of ISO-C is inferior to CT, and metal artifacts were more prominent, but the clinical value was equal. ISO-C-3D can be useful in planning operative reconstructions and can verify the reconstruction of articular surfaces and the position of implants with diagnostic image quality.

  16. ‘Inverted Y’ field radiotherapy planning with multi-leaf collimator: A single isocentric technique using multiple fields

    Directory of Open Access Journals (Sweden)

    Puja Sahai

    2015-01-01

    Full Text Available The purpose of our study is to describe a planning technique using multi-leaf collimator and asymmetric fields for irradiating an ‘inverted Y’ shaped geometry in a patient with testicular seminoma. The entire target area covering the para-aortic, pelvic, and inguinal nodal regions was split into three fields. Single isocenter half-beam block technique was employed. The fields were planned with antero-posterior and postero-anterior portals with a differential weightage. The dose was prescribed at the respective reference points of the fields. A uniform dose distribution for the entire portal was achieved without any under- or over-dosing at the field junctions.  

  17. Extreme hypofractionation for early prostate cancer: Biology meets technology.

    Science.gov (United States)

    De Bari, Berardino; Arcangeli, Stefano; Ciardo, Delia; Mazzola, Rosario; Alongi, Filippo; Russi, Elvio G; Santoni, Riccardo; Magrini, Stefano M; Jereczek-Fossa, Barbara A

    2016-11-01

    The aim of this review is to present the available radiobiological, technical and clinical data about extreme hypofractionation in primary prostate cancer radiotherapy. The interest in this technique is based on the favourable radiobiological characteristics of prostate cancer and supported by advantageous logistic aspects deriving from short overall treatment time. The clinical validity of short-term treatment schedule is proven by a body of non-randomised studies, using both isocentric (LINAC-based) or non-isocentric (CyberKnife(®)-based) stereotactic body irradiation techniques. Twenty clinical studies, each enrolling more than 40 patients for a total of 1874 treated patients, were revised in terms of technological setting, toxicity, outcome and quality of life assessment. The implemented strategies for the tracking of the prostate and the sparing of the rectal wall have been investigated with particular attention. The urinary toxicity after prostate stereotactic body irradiation seems slightly more pronounced as compared to rectal adverse events, and this is more evident for late occurring events, but no worse as respect to conventional fractionation schemes. As far as the rate of severe acute toxicity is concerned, in all the available studies the treatment was globally well tolerated. While awaiting long-term data on efficacy and toxicity, the analysed studies suggest that the outcome profile of this approach, alongside the patient convenience and reduced costs, is promising. Forty-eight ongoing clinical trials are also presented as a preview of the expectation from the near future.

  18. Establishing an Initial Electron Beam Model with Monte Carlo Simulation for a Single 6 MV X-ray Medical Linac Based on Particle Dynamics Characteristics

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hong-bin; KONG Xiao-xiao; LI Quan-feng; LIN Xiao-qi; BAO Shang-lian

    2009-01-01

    Objective:In this study,we try to establish an initial electron beam model by combining Monte Carlo simulation method with particle dynamic calculation (TRSV) for the single 6 MV X-ray accelerating waveguide of BJ- 6 medical linac. Methods and Materials:1. We adapted the treatment head configuration of BJ- 6 medical linac made by Beijing Medical Equipment Institute (BMEI) as the radiation system for this study. 2. Use particle dynamics calculation code called TRSV to drive out the initial electron beam parameters of the energy spectrum, the spatial intensity distribution, and the beam incidence angle. 3. Analyze the 6 MV X-ray beam characteristics of PDDc, OARc in a water phantom by using Monte Carlo simulation (BEAMnrc,DOSXYZnrc) for a preset of the initial electron beam parameters which have been determined by TRSV, do the comparisons of the measured results of PDDm, OARm in a real water phantom, and then use the deviations of calculated and measured results to slightly modify the initial electron beam model back and forth until the deviations meet the error less than 2%. Results:The deviations between the Monte Carlo simulation results of percentage depth doses at PDDc and off-axis ratios OARc and the measured results of PDDm and OARm in a water phantom were within 2%. Conclusion:When doing the Monte Carlo simulation to determine the parameters of an initial electron beam for a particular medical linac like BJ- 6, modifying some parameters based on the particle dynamics calculation code would give some more reasonable and more acceptable results.

  19. Radiation-Induced Peripheral Malignant Nerve Sheath Tumor Arising from Vestibular Schwannoma after Linac-Based Stereotactic Radiation Therapy: A Case Report and Review of Literatures

    Directory of Open Access Journals (Sweden)

    Putipun Puataweepong

    2012-01-01

    Full Text Available In recent years the use of stereotactic radiation for vestibular schwannomas has increased worldwide. However, malignant transformation associated with radiation, although uncommon, has been reported in recent publications. We present a case of the 34 year-old female who had left vestibular schwannoma and who underwent surgery and postoperative stereotactic radiotherapy (SRT, hypofraction in 2005. At 6 years after SRT, the patient came with left facial palsy and severe headache. CT brain revealed progression in size with cystic and hemorrhagic changes of the preexisting tumor at left CPA with new obstructive hydrocephalus. Partial tumor removal was done, and the pathological report was malignant peripheral nerve sheath tumor (MPNST. Regarding the uncertainty of carcinogenesis risk, we should still practice radiation therapy with caution, especially in the young patient with tumor predisposition syndrome. Because of low incidence of MPNST after radiation, it should not be a major decision about giving radiotherapy. However, with the poor prognosis of MPNST, this possibility should be explained to the patient before radiation treatment option.

  20. Linac-based extracranial radiosurgery with Elekta volumetric modulated arc therapy and an anatomy-based treatment planning system: Feasibility and initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Cilla, Savino, E-mail: savinocilla@gmail.com [Medical Physics Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Università Cattolica del Sacro Cuore, Campobasso (Italy); Deodato, Francesco; Macchia, Gabriella; Digesù, Cinzia [Radiotherapy Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Università Cattolica del Sacro Cuore, Campobasso (Italy); Ianiro, Anna; Viola, Pietro; Craus, Maurizio [Medical Physics Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Università Cattolica del Sacro Cuore, Campobasso (Italy); Valentini, Vincenzo [Radiotherapy Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Università Cattolica del Sacro Cuore, Campobasso (Italy); Radiation Oncology Unit, Policlinico Universitario “A. Gemelli”, Università Cattolica del Sacro Cuore, Roma (Italy); Piermattei, Angelo [Medical Physics Unit, Policlinico Universitario “A. Gemelli”, Università Cattolica del Sacro Cuore, Roma (Italy); Morganti, Alessio G. [Radiation Oncology Unit, Department of Experimental, Diagnostic and Specialty Medicine-DIMES, S. Orsola-Malpighi Hospital, University of Bologna, Bologna (Italy)

    2016-07-01

    We reported our initial experience in using Elekta volumetric modulated arc therapy (VMAT) and an anatomy-based treatment planning system (TPS) for single high-dose radiosurgery (SRS-VMAT) of liver metastases. This study included a cohort of 12 patients treated with a 26-Gy single fraction. Single-arc VMAT plans were generated with Ergo++ TPS. The prescription isodose surface (IDS) was selected to fulfill the 2 following criteria: 95% of planning target volume (PTV) reached 100% of the prescription dose and 99% of PTV reached a minimum of 90% of prescription dose. A 1-mm multileaf collimator (MLC) block margin was added around the PTV. For a comparison of dose distributions with literature data, several conformity indexes (conformity index [CI], conformation number [CN], and gradient index [GI]) were calculated. Treatment efficiency and pretreatment dosimetric verification were assessed. Early clinical data were also reported. Our results reported that target and organ-at-risk objectives were met for all patients. Mean and maximum doses to PTVs were on average 112.9% and 121.5% of prescribed dose, respectively. A very high degree of dose conformity was obtained, with CI, CN, and GI average values equal to 1.29, 0.80, and 3.63, respectively. The beam-on-time was on average 9.3 minutes, i.e., 0.36 min/Gy. The mean number of monitor units was 3162, i.e., 121.6 MU/Gy. Pretreatment verification (3%-3 mm) showed an optimal agreement with calculated values; mean γ value was 0.27 and 98.2% of measured points resulted with γ < 1. With a median follow-up of 16 months complete response was observed in 12/14 (86%) lesions; partial response was observed in 2/14 (14%) lesions. No radiation-induced liver disease (RILD) was observed in any patients as well no duodenal ulceration or esophagitis or gastric hemorrhage. In conclusion, this analysis demonstrated the feasibility and the appropriateness of high-dose single-fraction SRS-VMAT in liver metastases performed with Elekta VMAT and Ergo++ TPS. Preliminary clinical outcomes showed a high rate of local control and minimum incidence of acute toxicity.

  1. Multi-Beam Interference Advances and Applications: Nano-Electronics, Photonic Crystals, Metamaterials, Subwavelength Structures, Optical Trapping, and Biomedical Structures

    OpenAIRE

    Thomas K. Gaylord; Guy M. Burrow

    2011-01-01

    Research in recent years has greatly advanced the understanding and capabilities of multi-beam interference (MBI). With this technology it is now possible to generate a wide range of one-, two-, and three-dimensional periodic optical-intensity distributions at the micro- and nano-scale over a large length/area/volume. These patterns may be used directly or recorded in photo-sensitive materials using multi-beam interference lithography (MBIL) to accomplish subwavelength patterning. Advances in...

  2. Dosimetric comparison of intensity modulated radiotherapy isocentric field plans and field in field (FIF) forward plans in the treatment of breast cancer.

    Science.gov (United States)

    Al-Rahbi, Zakiya Salem; Al Mandhari, Zahid; Ravichandran, Ramamoorthy; Al-Kindi, Fatma; Davis, Cheriyathmanjiyil Anthony; Bhasi, Saju; Satyapal, Namrata; Rajan, Balakrishnan

    2013-01-01

    The present study is aimed at comparing the planning and delivery efficiency between three-dimensional conformal radiotherapy (3D-CRT), field-in-field, forward planned, intensity modulated radiotherapy (FIF-FP-IMRT), and inverse planned intensity modulated radiotherapy (IP-IMRT). Treatment plans of 20 patients with left-sided breast cancer, 10 post-mastectomy treated to a prescribed dose of 45 Gy to the chest wall in 20 fractions, and 10 post-breast-conserving surgery to a prescribed dose of 50 Gy to the whole breast in 25 fractions, with 3D-CRT were selected. The FiF-FP-IMRT plans were created by combining two open fields with three to four segments in two tangential beam directions. Eight different beam directions were chosen to create IP-IMRT plans and were inversely optimized. The homogeneity of dose to planning target volume (PTV) and the dose delivered to heart and contralateral breast were compared among the techniques in all the 20 patients. All the three radiotherapy techniques achieved comparable radiation dose delivery to PTV-95% of the prescribed dose covering > 95% of the breast PTV. The mean volume of PTV receiving 105% (V105) of the prescribed dose was 1.7% (range 0-6.8%) for IP-IMRT, 1.9% for FP-IMRT, and 3.7% for 3D-CRT. The homogeneity and conformity indices (HI and CI) were similar for 3D-CRT and FP-IMRT, whereas the IP-IMRT plans had better conformity index at the cost of less homogeneity. The 3D-CRT and FiF-FP-IMRT plans achieved similar sparing of critical organs. The low-dose volumes (V5Gy) in the heart and lungs were larger in IP-IMRT than in the other techniques. The value of the mean dose to the ipsilateral lung was higher for IP-IMRT than the values for with FiF-FP-IMRT and 3D-CRT. In the current study, the relative volume of contralateral breast receiving low doses (0.01, 0.6, 1, and 2Gy) was significantly lower for the FiF-FP-IMRT and 3D-CRT plans than for the IP-IMRT plan. Compared with 3D-CRT and IP-IMRT, FiF-FP-IMRT proved to be a simple and efficient planning technique for breast irradiation. It provided dosimetric advantages, significantly reducing the size of the hot spot and minimally improving the coverage of the target volume. In addition, it was felt that FiF-FP-IMRT required less planning time and easy field placements.

  3. Monte Carlo study of Siemens PRIMUS photoneutron production

    Science.gov (United States)

    Pena, J.; Franco, L.; Gómez, F.; Iglesias, A.; Pardo, J.; Pombar, M.

    2005-12-01

    Neutron production in radiotherapy facilities has been studied from the early days of modern linacs. Detailed studies are now possible using photoneutron capabilities of general-purpose Monte Carlo codes at energies of interest in medical physics. The present work studies the effects of modelling different accelerator head and room geometries on the neutron fluence and spectra predicted via Monte Carlo. The results from the simulation of a 15 MV Siemens PRIMUS linac show an 80% increase in the fluence scored at the isocentre when, besides modelling the components neccessary for electron/photon simulations, other massive accelerator head components are included. Neutron fluence dependence on inner treatment room volume is analysed showing that thermal neutrons have a 'gaseous' behaviour and then a 1/V dependence. Neutron fluence maps for three energy ranges, fast (E > 0.1 MeV), epithermal (1 eV < E < 0.1 MeV) and thermal (E < 1 eV), are also presented and the influence of the head components on them is discussed.

  4. Noninvasive referencing of intraocular tumors for external beam radiation therapy using optical coherence tomography: A proof of concept

    Energy Technology Data Exchange (ETDEWEB)

    Rüegsegger, Michael B.; Steiner, Patrick; Kowal, Jens H., E-mail: jens.kowal@artorg.unibe.ch [ARTORG Center for Biomedical Engineering Research, University of Bern, Bern 3010 (Switzerland); Geiser, Dominik [Berne University of Applied Sciences, HuCE OptoLab, 2501 (Switzerland); Pica, Alessia; Aebersold, Daniel M. [Department of Radiation Oncology, Inselspital, Bern University Hospital, University of Bern, Bern 3010 (Switzerland)

    2014-08-15

    Purpose: External beam radiation therapy is currently considered the most common treatment modality for intraocular tumors. Localization of the tumor and efficient compensation of tumor misalignment with respect to the radiation beam are crucial. According to the state of the art procedure, localization of the target volume is indirectly performed by the invasive surgical implantation of radiopaque clips or is limited to positioning the head using stereoscopic radiographies. This work represents a proof-of-concept for direct and noninvasive tumor referencing based on anterior eye topography acquired using optical coherence tomography (OCT). Methods: A prototype of a head-mounted device has been developed for automatic monitoring of tumor position and orientation in the isocentric reference frame for LINAC based treatment of intraocular tumors. Noninvasive tumor referencing is performed with six degrees of freedom based on anterior eye topography acquired using OCT and registration of a statistical eye model. The proposed prototype was tested based on enucleated pig eyes and registration accuracy was measured by comparison of the resulting transformation with tilt and torsion angles manually induced using a custom-made test bench. Results: Validation based on 12 enucleated pig eyes revealed an overall average registration error of 0.26 ± 0.08° in 87 ± 0.7 ms for tilting and 0.52 ± 0.03° in 94 ± 1.4 ms for torsion. Furthermore, dependency of sampling density on mean registration error was quantitatively assessed. Conclusions: The tumor referencing method presented in combination with the statistical eye model introduced in the past has the potential to enable noninvasive treatment and may improve quality, efficacy, and flexibility of external beam radiotherapy of intraocular tumors.

  5. Search for excited electron production using Di-electron + photon signature and search for new heavy neutral gauge boson using Di-electron signature with ATLAS at Vs=TeV

    CERN Document Server

    Abdelalim Aly, Ahmed Aly

    The ATLAS detector has been used to search for singly produced excited electron (e*) decaying to e+γ as well as heavy neutral gauge boson (Z') decaying to e-e+. For the Z' search, results are based on pp collisions at center-of-mass energy 7 TeV corresponding to an integrated luminosity of about 39 pb-1 of 2010 data. No statistically significant excess above the Standard Model processes was observed. Upper limits at 95% CL are set on the cross-section times branching ratio of narrow Z' resonances decaying to electrons as a function of the resonance mass. A lower mass limits on the Sequential Standard Model and on E6-motivated Z' models. For the e* search, results are based on a dataset of 2 fb-1 of 2011 data. Upper limits at 95% CL are set on the cross-section times branching ratio of pp to ee* to eeγ. These limits allow to set a lower mass limit on e*.

  6. Contribution of the deep-inspiration breath-hold technique in patients treated for a left breast cancer by mono-isocentric conformational irradiation; Apport du blocage inspiratoire profond chez des patientes traitees pour un cancer du sein gauche par irradiation conformationnelle mono-isocentrique

    Energy Technology Data Exchange (ETDEWEB)

    Zioueche, A.; Mege, A.; Bodez, V.; Rauglaudre, G. de [Institut Sainte-Catherine, Avignon (France)

    2011-10-15

    The authors report a study which aimed at assessing the benefit of a deep-inspiration-breath-hold on heart sparing in 31 women treated in the left breast or wall and locoregional ganglionary areas by three-dimensional conformational irradiation with field-in-field optimization. All heart and lung parameters (delivered doses) have been significantly improved by a deep-inspiration-breath-hold. Short communication

  7. High energy photon reference for radiation protection: technical design of the LINAC beam and ionization chambers; and calculation of monoenergetic conversion coefficients

    Science.gov (United States)

    Dusciac, D.; Bordy, J.-M.; Daures, J.; Blideanu, V.

    2016-09-01

    In this work, we present the results of the first part of a research project aimed at offering a complete response to dosimeters providers and nuclear physicists' demands for high-energy (6 - 9 MeV) photon beams for radiation protection purposes. Classical facilities allowing the production of high-energy photonic radiation (proton accelerators, nuclear reactors) are very rare and need large investment for development and use. A novel solution is proposed, consisting in the use of a medical linear accelerator, allowing a significant decrease of all costs.Using Monte Carlo simulations (MCNP5 and PENELOPE codes), a specifically designed electron-photon conversion target allowing for obtaining a high energy photon beam (with an average energy weighted by fluence of about 6 MeV) has been built for radiation protection purposes. Due to the specific design of the target, this "realistic" radiation protection high-energy photon beam presents a uniform distribution of air kerma rate at a distance of 1 m, over a 30 × 30 cm2 surface. Two graphite cavity ionizing chambers for ionometric measurements have been built. For one of these chambers, the charge collection volume has been measured allowing for its use as a primary standard. The second ionizing chamber is used as a transfer standard; as such it has been calibrated in a 60Co beam, and in the high energy photon beam for radiation protection.The measurements with these ionizing chambers allowed for an evaluation of the air kerma rate in the LINAC based high-energy photon beam for radiation protection: the values cover a range between 36 mGy/h and 210 mGy/h, compatible with radiation protection purposes.Finally, using Monte Carlo simulations, conversion coefficients from air kerma to dose equivalent quantities have been calculated in the range between 10 keV and 22.4 MeV, for the spectral distribution of the fluence corresponding to the beam produced by the linear accelerator of the LNE-LNHB.

  8. High energy photon reference for radiation protection: technical design of the LINAC beam and ionization chambers; and calculation of monoenergetic conversion coefficients

    Directory of Open Access Journals (Sweden)

    Dusciac D.

    2016-01-01

    Full Text Available In this work, we present the results of the first part of a research project aimed at offering a complete response to dosimeters providers and nuclear physicists’ demands for high-energy (6 – 9 MeV photon beams for radiation protection purposes. Classical facilities allowing the production of high-energy photonic radiation (proton accelerators, nuclear reactors are very rare and need large investment for development and use. A novel solution is proposed, consisting in the use of a medical linear accelerator, allowing a significant decrease of all costs.Using Monte Carlo simulations (MCNP5 and PENELOPE codes, a specifically designed electron-photon conversion target allowing for obtaining a high energy photon beam (with an average energy weighted by fluence of about 6 MeV has been built for radiation protection purposes. Due to the specific design of the target, this “realistic” radiation protection high-energy photon beam presents a uniform distribution of air kerma rate at a distance of 1 m, over a 30 × 30 cm2 surface. Two graphite cavity ionizing chambers for ionometric measurements have been built. For one of these chambers, the charge collection volume has been measured allowing for its use as a primary standard. The second ionizing chamber is used as a transfer standard; as such it has been calibrated in a 60Co beam, and in the high energy photon beam for radiation protection.The measurements with these ionizing chambers allowed for an evaluation of the air kerma rate in the LINAC based high-energy photon beam for radiation protection: the values cover a range between 36 mGy/h and 210 mGy/h, compatible with radiation protection purposes.Finally, using Monte Carlo simulations, conversion coefficients from air kerma to dose equivalent quantities have been calculated in the range between 10 keV and 22.4 MeV, for the spectral distribution of the fluence corresponding to the beam produced by the linear accelerator of the LNE-LNHB.

  9. La mise ouvre de la technique Mono-isocentrique dans les cancers des VADS et des sein

    OpenAIRE

    2011-01-01

    Les techniques classiques de traitement dans le cancer des VADS et les cancers de seins utilisent plusieurs isocentre pour le positionnement des différents faisceaux de traitement. Les incertitudes de positionnement de chacun de ces isocentres ont pour conséquences des problèmes de reproductibilité de jonction entre les différents faisceaux de traitement. L’utilisation d’un isocentre de traitement unique permet de maitriser ces jonctions et autorise un positionnement unique pou...

  10. The Compact Pulsed Hadron Source Construction Status

    CERN Document Server

    Wei, Jie; Cai, Jinchi; Chen, Huaibi; Cheng, Cheng; Du, Qiang; Du, Taibin; Feng, Qixi; Feng, Zhe; Gong, Hui; Guan, Xialing; Han, Xiaoxue; Huang, Tuchen; Huang, Zhifeng; Li, Renkai; Li, Wenqian; Loong, Chun-Keung; Tang, Chuanxiang; Tian, Yang; Wang, Xuewu; Xie, Xiaofeng; Xing, Qingzi; Xiong, Zhengfeng; Xu, Dong; Yang, Yigang; Zeng, Zhi; Zhang, Huayi; Zhang, Xiaozhang; Zheng, Shu-xin; Zheng, Zhihong; Zhong, Bin; Billen, James; Young, Lloyd; Fu, Shinian; Tao, Juzhou; Zhao, Yaliang; Guan, Weiqiang; He, Yu; Li, Guohua; Li, Jian; Zhang, Dong-sheng; Li, Jinghai; Liang, Tianjiao; Liu, Zhanwen; Sun, Liangting; Zhao, Hongwei; Shao, Beibei; Stovall, James

    2010-01-01

    This paper reports the design and construction status, technical challenges, and future perspectives of the proton-linac based Compact Pulsed Hadron Source (CPHS) at the Tsinghua University, Beijing, China

  11. SUPERCONDUCTING NON-SCALING FFAG GANTRY FOR CARBON-PROTON CANCER THERAPY

    Energy Technology Data Exchange (ETDEWEB)

    TRBOJEVIC,D.; GUPTA, R.; PARKER, B.; KEIL, E.; SESSLER, A.M.

    2007-06-25

    We report on improvements in the non-scaling Fixed Field Alternating Gradient (FFAG) gantry design. As we previously reported, a major challenge of the carbodproton cancer therapy facilities is isocentric gantry design. The weight of the isocentric gantry transport elements in the latest Heidelberg carbon/proton facility is 135 tons. In this report we detail improvements to the previous non-scaling gantry design. We estimate that this non-scaling FFAG gantry would be almost hundred times lighter than traditional heavy ion gantries. Very strong focusing with small dispersion permits passage of different energies of carbon beams through the gantry's fixed magnetic field.

  12. The radiation isocenter verification using an electronic system of image portal; Verificacion del isocentro de radiacion utilizando un sistema electronico de imagen portal

    Energy Technology Data Exchange (ETDEWEB)

    Merino Gestoso, J. A.; Portas Ferradas, B. C.; Rosa Menendez, P.; Chapel Gomez, M. L.; Fernandez Cerezo, S.; Vazquez Varela, P.

    2013-07-01

    In this paper we present a procedure optimized for verification the isocenter of radiation with respect to the rotation of the gantry and the turn isocentric table of two accelerators SIEMENS, ONCOR and ARTISTE with a mannequin developed in our service and analyzing the images acquired with the EPID from each of the teams. (Author)

  13. Design and performance criteria for medical electron accelerators

    Science.gov (United States)

    Nunan, Craig S.

    1985-05-01

    A brief comparison is made of the design and performance of early and modern isocentric microwave linear accelerators for radiotherapy. Generally accepted criteria for the design of current machines are presented, along with a rationale for their selection. The current development of international standards for safety and performance of medical electron accelerators is reviewed.

  14. CPO-IPN collaboration for proton therapy; La collaboration CPO-IPN pour la protontherapy

    Energy Technology Data Exchange (ETDEWEB)

    Arianer, J.; Buhour, J.M.; Coat, F.; Mueller, A.C. [Services Techniques, Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France); Mazal, A. [CPO, Paris-11 Univ., 91 - Orsay (France)

    1999-11-01

    Since January 1997 a collaboration between CPO-IPN has been started in order to develop proton therapy instruments at Orsay. The final purposes are to build an isocentric gantry and further a medically dedicated super-conducting proton accelerator for treatment of cancers. (authors) 6 figs., 1 tab.

  15. The use of enriched 6Li and 7Li Lif:Mg,Cu,P glass-rod thermoluminescent dosemeters for linear accelerator out-of-field radiation dose measurements.

    Science.gov (United States)

    Takam, R; Bezak, E; Liu, G; Marcu, L

    2012-06-01

    (6)LiF:Mg,Cu,P and (7)LiF:Mg,Cu,P glass-rod thermoluminescent dosemeters (TLDs) were used for measurements of out-of-field photon and neutron doses produced by Varian iX linear accelerator. Both TLDs were calibrated using 18-MV X-ray beam to investigate their dose-response sensitivity and linearity. CR-39 etch-track detectors (Luxel+, Landauer) were employed to provide neutron dose data to calibrate (6)LiF:Mg,Cu,P TLDs at various distances from the isocentre. With cadmium filters employed, slow neutrons (neutrons. The average in-air photon dose equivalents per monitor unit (MU) ranged from 1.5±0.4 to 215.5±94.6 μSv at 100 and 15 cm from the isocentre, respectively. Based on the cross-calibration factors obtained with CR-39 etch-track detectors, the average in-air fast neutron dose equivalents per MU range from 10.6±3.8 to 59.1±49.9 μSv at 100 and 15 cm from the isocentre, respectively. Contribution of thermal neutrons to total neutron dose equivalent was small: 3.1±7.2 μSv per MU at 15 cm from the isocentre.

  16. Evaluation of stereotactic body radiotherapy (SBRT) boost in the management of endometrial cancer.

    Science.gov (United States)

    Demiral, S; Beyzadeoglu, M; Uysal, B; Oysul, K; Kahya, Y Elcim; Sager, O; Dincoglan, F; Gamsiz, H; Dirican, B; Surenkok, S

    2013-01-01

    The purpose of this study is to evaluate the use of linear accelerator (LINAC)-based stereotactic body radiotherapy (SBRT) boost with multileaf collimator technique after pelvic radiotherapy (RT) in patients with endometrial cancer. Consecutive patients with endometrial cancer treated using LINAC-based SBRT boost after pelvic RT were enrolled in the study. All patients had undergone surgery including total abdominal hysterectomy and bilateral salpingo-oophorectomy ± pelvic/paraortic lymphadenectomy before RT. Prescribed external pelvic RT dose was 45 Gray (Gy) in 1.8 Gy daily fractions. All patients were treated with SBRT boost after pelvic RT. The prescribed SBRT boost dose to the upper two thirds of the vagina including the vaginal vault was 18 Gy delivered in 3 fractions with 1-week intervals. Gastrointestinal and genitourinary toxicity was assessed using the Common Terminology Criteria for Adverse Events version 3 (CTCAE v3).Between April 2010 and May 2011, 18 patients with stage I-III endometrial cancer were treated with LINAC-based SBRT boost after pelvic RT. At a median follow-up of 24 (8-26) months with magnetic resonance imaging (MRI) and gynecological examination, local control rate of the study group was 100 % with negligible acute and late toxicity.LINAC-based SBRT boost to the vaginal cuff is a feasible gynecological cancer treatment modality with excellent local control and minimal toxicity that may replace traditional brachytherapy boost in the management of endometrial cancer.

  17. Overview of the Defense Programs Research and Technology Development Program for Fiscal Year 1993

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-30

    This documents presents a programmatic overview and program element plan summaries for conceptual design and assessment; physics; computation and modeling; system engineering science and technology; electronics, photonics, sensors, and mechanical components; chemistry and materials; special nuclear materials, tritium, and explosives.

  18. Optimization and Comparison of Different Digital Mammographic Tomosynthesis Reconstruction Methods

    Science.gov (United States)

    2008-04-01

    isocentric motion in breast tomosynthesis. We have published our results in Medical Physics , the premiere peer-reviewed journal in the field of... Medical Physics ; please see Appendix #1 for the reprinted publication. 1.2. Characterize the effect of three acquisition parameters including total...working on a Medical Physics journal manuscript preparation for GFB algorithm. We have used impulse response and MTF analysis method to compare BP and

  19. Comparison between In-house developed and Diamond commercial software for patient specific independent monitor unit calculation and verification with heterogeneity corrections.

    Science.gov (United States)

    Kuppusamy, Vijayalakshmi; Nagarajan, Vivekanandan; Jeevanandam, Prakash; Murugan, Lavanya

    2016-02-01

    The study was aimed to compare two different monitor unit (MU) or dose verification software in volumetric modulated arc therapy (VMAT) using modified Clarkson's integration technique for 6 MV photons beams. In-house Excel Spreadsheet based monitor unit verification calculation (MUVC) program and PTW's DIAMOND secondary check software (SCS), version-6 were used as a secondary check to verify the monitor unit (MU) or dose calculated by treatment planning system (TPS). In this study 180 patients were grouped into 61 head and neck, 39 thorax and 80 pelvic sites. Verification plans are created using PTW OCTAVIUS-4D phantom and also measured using 729 detector chamber and array with isocentre as the suitable point of measurement for each field. In the analysis of 154 clinically approved VMAT plans with isocentre at a region above -350 HU, using heterogeneity corrections, In-house Spreadsheet based MUVC program and Diamond SCS showed good agreement TPS. The overall percentage average deviations for all sites were (-0.93% + 1.59%) and (1.37% + 2.72%) for In-house Excel Spreadsheet based MUVC program and Diamond SCS respectively. For 26 clinically approved VMAT plans with isocentre at a region below -350 HU showed higher variations for both In-house Spreadsheet based MUVC program and Diamond SCS. It can be concluded that for patient specific quality assurance (QA), the In-house Excel Spreadsheet based MUVC program and Diamond SCS can be used as a simple and fast accompanying to measurement based verification for plans with isocentre at a region above -350 HU.

  20. Introduction of the Mammography unit; SEPIO series

    Energy Technology Data Exchange (ETDEWEB)

    Nanbu, Yukiko; Sasaki, Osamu; Tsuji, Hisao [Shimadzu Corp., Medical Systems Division, Kyoto (Japan)

    2003-06-01

    Mammography unit SEPIO series are designed for the both screening and diagnosis of the breast cancer. SEPIO series have the following features; iso-centric C-arm rotation leads to high throughput, two phase compression method called Twincomp minimizes the blind are near chest wall and the bi-angular X-ray tube contributes to better image quality. Furthermore optional MaxVision system which has a function to pull the breast toward the film is introduced to SEPIO series. (author)

  1. Three independent one-dimensional margins for single-fraction frameless stereotactic radiosurgery brain cases using CBCT

    CERN Document Server

    Zhang, Qinghui; Burman, Chandra; Song, Yulin; Zhang, Mutian

    2013-01-01

    Setting a proper margin is crucial for not only delivering the required radiation dose to a target volume, but also reducing the unnecessary radiation to the adjacent organs at risk. This study investigated the independent one-dimensional symmetric and asymmetric margins between the clinical target volume (CTV) and the planning target volume (PTV) for linac-based single-fraction frameless stereotactic radiosurgery (SRS).

  2. Effect of treatment modality on the hypothalamic-pituitary function of patients treated with radiation therapy for pituitary adenomas: Hypothalamic dose and endocrine outcomes.

    OpenAIRE

    Andrew eElson; Joseph eBovi; Kawaljeet eKaur; Diana eMaas; Grant eSinson; Chris eSchultz

    2014-01-01

    Background: Both fractionated external beam radiotherapy and single fraction radiosurgery for pituitary adenomas are associated with the risk of hypothalamic-pituitary (HP) axis dysfunction.Objective: To analyze the effect of treatment modality (Linac, TomoTherapy, or Gamma Knife) on hypothalamic dose and correlate these with HP-Axis deficits after radiotherapy.Methods:Radiation plans of patients treated postoperatively for pituitary adenomas using Linac-based 3D Conformal Radiotherapy (CRT) ...

  3. Effect of Treatment Modality on the Hypothalamic–Pituitary Function of Patients Treated with Radiation Therapy for Pituitary Adenomas: Hypothalamic Dose and Endocrine Outcomes

    OpenAIRE

    Elson, Andrew; Bovi, Joseph; Kaur, Kawaljeet; Maas, Diana; Sinson, Grant; Schultz, Chris

    2014-01-01

    Background: Both fractionated external beam radiotherapy and single fraction radiosurgery for pituitary adenomas are associated with the risk of hypothalamic–pituitary (HP) axis dysfunction. Objective: To analyze the effect of treatment modality (Linac, TomoTherapy, or gamma knife) on hypothalamic dose and correlate these with HP-axis deficits after radiotherapy. Methods: Radiation plans of patients treated post-operatively for pituitary adenomas using Linac-based 3D-conformal radiother...

  4. Spallation neutron source and other high intensity froton sources

    Energy Technology Data Exchange (ETDEWEB)

    Weiren Chou

    2003-02-06

    This lecture is an introduction to the design of a spallation neutron source and other high intensity proton sources. It discusses two different approaches: linac-based and synchrotron-based. The requirements and design concepts of each approach are presented. The advantages and disadvantages are compared. A brief review of existing machines and those under construction and proposed is also given. An R&D program is included in an appendix.

  5. Abdominal CT during pregnancy: a phantom study on the effect of patient centring on conceptus radiation dose and image quality

    Energy Technology Data Exchange (ETDEWEB)

    Solomou, G.; Damilakis, J. [University of Crete, Faculty of Medicine, Department of Medical Physics, Heraklion, P.O. Box 2208, Crete (Greece); Papadakis, A.E. [University Hospital of Heraklion, Department of Medical Physics, Heraklion, P.O. Box 1352, Crete (Greece)

    2015-04-01

    To investigate the effect of patient centring on conceptus radiation dose and image quality in abdominal CT during pregnancy. Three anthropomorphic phantoms that represent a pregnant woman at the three trimesters of gestation were subjected to a routine abdominal CT. Examinations were performed with fixed mAs (mAs{sub f}) and with the automatic exposure control system (AEC) activated. The percent reduction between mAs{sub f} and modulated mAs (mAs{sub mod}) was calculated. Conceptus dose (D{sub c}) was measured using thermoluminescent dosimeters. To study the effect of misplacement of pregnant women on D{sub c}, each phantom was positioned at various locations relative to gantry isocentre. Image quality was evaluated on the basis of image noise, signal-to-noise ratio, and contrast-to-noise ratio. The maximum reduction between mAs{sub f} and mAs{sub mod} was 59.8 %, while the corresponding D{sub C} reduction was 59.3 %. D{sub C} was found to decrease by up to 25 % and 7.9 % for phantom locations below and above the isocentre, respectively. Image quality deteriorated when AEC was activated, and it was progressively improved from lower to higher than the isocentre locations. Centring errors do not result in an increase in D{sub c}. To maintain image quality, accurate centring is required. (orig.)

  6. Single-isocenter hybrid IMRT plans versus two-isocenter conventional plans and impact of intrafraction motion for the treatment of breast cancer with supraclavicular lymph nodes involvement.

    Science.gov (United States)

    Amoush, Ahmad; Murray, Eric; Yu, Jennifer S; Xia, Ping

    2015-07-08

    The purpose of this study was to compare the single-isocenter, four-field hybrid IMRT with the two-isocenter techniques to treat the whole breast and supraclavicular fields and to investigate the intrafraction motions in both techniques in the superior direction. Fifteen breast cancer patients who underwent lumpectomy and adjuvant radiation to the whole breast and supraclavicular (SCV) fossa at our institution were selected for this study. Two planning techniques were compared for the treatment of the breast and SCV lymph nodes. The patients were divided into three subgroups according to the whole breast volume. For the two-isocenter technique, conventional wedged or field-within-a-field tangents (FIF) were used to match with the same anterior field for the SCV region. For the single-isocenter technique, four-field hybrid IMRT was used for the tangent fields matched with a half blocked anterior field for the SCV region. To simulate the intrafraction uncertainties in the longitudinal direction for both techniques, the treatment isocenters were shifted by 1 mm and 2 mm in the superior direction. The average breast clinical tumor volume (CTV) receiving 100% (V(100%)) of the prescription dose (50 Gy) was 99.3% ± 0.5% and 96.4% ± 1.2% for the for two-isocenter and single-isocenter plans (р 20 Gy (V(20Gy)) and the heart receiving > 30 Gy (V(30Gy)) were 13.6% vs. 14.3% (р = 0.03) and 1.25% vs. 1.2% (р = 0.62), respectively. Shifting the treatment isocenter by 1 mm and 2 mm superiorly showed that the average maximum dose to 1 cc of the breast volume was 55.5 ± 1.8 Gy and 58.6 ± 4.3 Gy in the two-isocentric technique vs. 56.4 ± 2.1 Gy and 59.1 ± 5.1 Gy in the single-isocentric technique (р = 0.46, 0.87), respectively. The single-isocenter technique using four-field hybrid IMRT approach resulted in comparable plan quality as the two-isocentric technique. The single-isocenter technique is more sensitive to intra-fraction motion in the superior direction compared to

  7. Automated treatment planning for a dedicated multi-source intra-cranial radiosurgery treatment unit accounting for overlapping structures and dose homogeneity

    Energy Technology Data Exchange (ETDEWEB)

    Ghobadi, Kimia; Ghaffari, Hamid R. [Department of Mechanical and Industrial Engineering, University of Toronto, Ontario M5S 3G8 (Canada); Aleman, Dionne M. [Department of Mechanical and Industrial Engineering, University of Toronto, Ontario M5S 3G8 (Canada); Institute of Health Policy, Management and Evaluation, University of Toronto, Ontario M5T 3M6 (Canada); Techna Institute, University Health Network, Ontario M5G 1P5 (Canada); Jaffray, David A. [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Ontario M5T 2M9 (Canada); Department of Radiation Oncology, University of Toronto, Ontario M5S 3E2 (Canada); Department of Medical Biophysics, University of Toronto, Ontario M5G 2M9 (Canada); Institute of Biomaterial and Biomedical Engineering, University of Toronto, Ontario M5S 2J7 (Canada); Techna Institute, University Health Network, Ontario M5G 1P5 (Canada); Ontario Cancer Institute, Ontario M5G 0A3 (Canada); Ruschin, Mark [Department of Medical Physics, Odette Cancer Centre, Toronto, Ontario M4N 3M5 (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3E2 (Canada)

    2013-09-15

    Purpose: The purpose of this work is to advance the two-step approach for Gamma Knife{sup ®} Perfexion™ (PFX) optimization to account for dose homogeneity and overlap between the planning target volume (PTV) and organs-at-risk (OARs).Methods: In the first step, a geometry-based algorithm is used to quickly select isocentre locations while explicitly accounting for PTV-OARs overlaps. In this approach, the PTV is divided into subvolumes based on the PTV-OARs overlaps and the distance of voxels to the overlaps. Only a few isocentres are selected in the overlap volume, and a higher number of isocentres are carefully selected among voxels that are immediately close to the overlap volume. In the second step, a convex optimization is solved to find the optimal combination of collimator sizes and their radiation duration for each isocentre location.Results: This two-step approach is tested on seven clinical cases (comprising 11 targets) for which the authors assess coverage, OARs dose, and homogeneity index and relate these parameters to the overlap fraction for each case. In terms of coverage, the mean V{sub 99} for the gross target volume (GTV) was 99.8% while the V{sub 95} for the PTV averaged at 94.6%, thus satisfying the clinical objectives of 99% for GTV and 95% for PTV, respectively. The mean relative dose to the brainstem was 87.7% of the prescription dose (with maximum 108%), while on average, 11.3% of the PTV overlapped with the brainstem. The mean beam-on time per fraction per dose was 8.6 min with calibration dose rate of 3.5 Gy/min, and the computational time averaged at 205 min. Compared with previous work involving single-fraction radiosurgery, the resulting plans were more homogeneous with average homogeneity index of 1.18 compared to 1.47.Conclusions: PFX treatment plans with homogeneous dose distribution can be achieved by inverse planning using geometric isocentre selection and mathematical modeling and optimization techniques. The quality of the

  8. Complete description of polarization effects in e^+e^- pair production by a photon in the field of a strong laser wave

    CERN Document Server

    Ivanov, D Y; Serbo, V G

    2004-01-01

    We consider production of a e^+e^- pair by a high-energy photon in the field of a strong laser wave. A probability of this process for circularly or linearly polarized laser photons and for arbitrary polarization of all other particles is calculated. We obtain the complete set of functions which describe such a probability in a compact invariant form. Besides, we discuss in some detail the polarization effects in the kinematics relevant to the problem of electron-photon conversion at photon-photon and electron-photon colliders.

  9. Das ATLAS experiment : Die Teilchen schlagen zurück

    CERN Multimedia

    Michael Barnett - Erik Johansson

    2006-01-01

    Shot with a bug's eye view of the inside of the detector. The viewer is shown the inner, middle and outer sections of the ATLAS detector. The narrator describes how different parts of the detector are able to detect 6 different types of particles: electrons, photons, protons, neutrons, muons and neutrinos.

  10. Photon neutrino-production in a chiral EFT for nuclei and extrapolation to $E_{\

    CERN Document Server

    Zhang, Xilin

    2013-01-01

    We carry out a series of studies on pion and photon productions in neutrino/electron/photon--nucleus scatterings. The low energy region is investigated by using a chiral effective field theory for nuclei. The results for the neutral current induced photon production ($\\gamma$-NCP) are then extrapolated to neutrino energy $E_{\

  11. The EPRDATA Format: A Dialogue

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Henry Grady III [Los Alamos National Laboratory

    2015-08-18

    Recently the Los Alamos Nuclear Data Team has communicated certain issues of concern in relation to the new electron/photon/relaxation ACE data format as released in the eprdata12 library. In this document those issues are parsed, analyzed, and answered.

  12. Ledge-flow-controlled catalyst interface dynamics during Si nanowire growth

    DEFF Research Database (Denmark)

    Hofmann, S; Sharma, R; Wirth, CT

    2008-01-01

    Self-assembled nanowires offer the prospect of accurate and scalable device engineering at an atomistic scale for applications in electronics, photonics and biology. However, deterministic nanowire growth and the control of dopant profiles and heterostructures are limited by an incomplete...

  13. Test beam results of a stereo preshower integrated in the liquid argon accordion calorimeter

    CERN Document Server

    Davis, R; Greenious, G; Kitching, P; Olsen, B; Pinfold, James L; Rodning, N L; Boos, E; Zhautykov, B O; Aubert, Bernard; Bazan, A; Beaugiraud, B; Boniface, J; Colas, Jacques; Eynard, G; Jézéquel, S; Le Flour, T; Linossier, O; Nicoleau, S; Sauvage, G; Thion, J; Van den Plas, D; Wingerter-Seez, I; Zitoun, R; Zolnierowski, Y; Chmeissani, M; Fernández, E; Garrido, L; Martínez, M; Padilla, C; Citterio, M; Gordon, H A; Lissauer, D; Ma, H; Makowiecki, D S; Radeka, V; Rahm, David Charles; Rescia, S; Stephani, D; Takai, H; Baisin, L; Berset, J C; Chevalley, J L; Gianotti, F; Gildemeister, O; Marin, C P; Nessi, Marzio; Poggioli, Luc; Richter, W; Vuillemin, V; Baze, J M; Delagnes, E; Gosset, L G; Lavocat, P; Lottin, J P; Mansoulié, B; Meyer, J P; Renardy, J F; Schwindling, J; Simion, S; Taguet, J P; Teiger, J; Walter, C; Collot, J; de Saintignon, P; Hostachy, J Y; Mahout, G; Barreiro, F; Del Peso, J; García, J; Hervás, L; Labarga, L; Romero, P; Scheel, C V; Chekhtman, A; Cousinou, M C; Dargent, P; Dinkespiler, B; Etienne, F; Fassnacht, P; Fouchez, D; Martin, L; Miotto, A; Monnier, E; Nagy, E; Olivetto, C; Tisserant, S; Battistoni, G; Camin, D V; Cavalli, D; Costa, G; Cozzi, L; Fedyakin, N N; Ferrari, A; Mandelli, L; Mazzanti, M; Perini, L; Resconi, S; Sala, P R; Beaudoin, G; Depommier, P; León-Florián, E; Leroy, C; Roy, P; Augé, E; Breton, D; Chase, Robert L; Chollet, J C; de La Taille, C; Fayard, Louis; Fournier, D; González, J; Hrisoho, A T; Jacquier, Y; Merkel, B; Nikolic, I A; Noppe, J M; Parrour, G; Pétroff, P; Puzo, P; Richer, J P; Schaffer, A C; Seguin-Moreau, N; Serin, L; Tisserand, V; Veillet, J J; Vichou, I; Canton, B; David, J; Genat, J F; Imbault, D; Le Dortz, O; Savoy-Navarro, Aurore; Schwemling, P; Eek, L O; Lund-Jensen, B; Söderqvist, J; Astbury, Alan; Keeler, Richard K; Lefebvre, M; Robertson, S; White, J

    1998-01-01

    This paper describes the construction of an integrated preshower within the RD3 liquid argon accordion calorimeter. It has a stereo view which enables the measurement of two transverse coordinates. The prototype was tested at CERN with electrons, photons and muons to validate its capability to work at LHC ( Energy resolution, impact point resolution, angular resolution, $\\pi^o$/$\\gamma$ rejection ).

  14. L'aimant le plus puissant du monde est au CERN

    CERN Multimedia

    2007-01-01

    The CMS detector, name of "Compact Muon Solenoid" aims at clearing the "new physics" and must permit, among other things, to explain why fundamental particles, such as electrons, photons and hadrons, have masses and thus differents "weights". (1/2 page)

  15. In vivo dosimetry during tangential breast treatment

    Energy Technology Data Exchange (ETDEWEB)

    Heukelom, S.; Lanson, J.H.; Tienhoven, G. van; Mijnheer, B.J. (Nederlands Kanker Inst. ' Antoni van Leeuwenhoekhuis' , Amsterdam (Netherlands))

    1991-12-01

    Three-dimensional (3-D) dose distribution as calculated in clinical practice for tangential breast treatment was verified through in vivo dosimetry. Clinical practice at Netherlands Cancer Institute implies use of 8MV X-ray beams, 2-D treatment planning system, collimator rotation and a limited set of patient data for dose calculations. By positioning diodes at the central beam axes as well as in the periphery of the breast the magnitude of dose values at the isocentre and in points situated in high-dose regions behind the lung could be assessed. The position of diodes was verified by means of an on-line portal imaging device. Reproducibility of these in vivo dose measurements was better than 2% (1SD). This study shows that on the average dose delivery at the isocentre is 2% less at the points behind the lung, 5.7% higher with respect to the calculated dose values. Detailed analysis of these in vivo dosimetry results, based on dose measurements performed with a breast shaped phantom, yielded the magnitudes of errors in predicted dose due to several limitations in dose calculation algorithms and dose calculation procedure. These limitations are each introducing an error of several percent but are compensating each other for the dose calculation at the isocentre. It is concluded that dose distribution in patient for this treatment technique and dose calculation procedure can be predicted with a 2-D treatment planning system in an acceptable way. A more accurate prediction of dose distribution can be performed but requires an estimation of the lack of scatter due to missing tissue, the change in the dose distribution due to oblique incident beams and incorporation of the actual output of the treatment machine in the assessment of the number of monitor units. (author). 28 refs.; 3 figs.; 4 tabs.

  16. ELECTRON BEAM ION SOURCE PREINJECTOR PROJECT (EBIS) CONCEPTUAL DESIGN REPORT.

    Energy Technology Data Exchange (ETDEWEB)

    ALESSI, J.; BARTON, D.; BEEBE, E.; GASSNER, D.; ET AL.

    2005-02-28

    This report describes a new heavy ion pre-injector for the Relativistic Heavy Ion Collider (RHIC) based on a high charge state Electron Beam Ion Source (EBIS), a Radio Frequency Quadrupole (RFQ) accelerator, and a short Linac. The highly successful development of an EBIS at BNL now makes it possible to replace the present pre-injector that is based on an electrostatic Tandem with a reliable, low maintenance Linac-based pre-injector. Linac-based pre-injectors are presently used at most accelerator and collider facilities with the exception of RHIC, where the required gold beam intensities could only be met with a Tandem until the recent EBIS development. EBIS produces high charge state ions directly, eliminating the need for the two stripping foils presently used with the Tandem. Unstable stripping efficiencies of these foils are a significant source of luminosity degradation in RHIC. The high reliability and flexibility of the new Linac-based pre-injector will lead to increased integrated luminosity at RHIC and is an essential component for the long-term success of the RHIC facility. This new pre-injector, based on an EBIS, also has the potential for significant future intensity increases and can produce heavy ion beams of all species including uranium beams and, as part of a future upgrade, might also be used to produce polarized {sup 3}He beams. These capabilities will be critical to the future luminosity upgrades and electron-ion collisions in RHIC. The new RFQ and Linac that are used to accelerate beams from the EBIS to an energy sufficient for injection into the Booster are both very similar to existing devices already in operation at other facilities. Injection into the Booster will occur at the same location as the existing injection from the Tandem.

  17. Effect of treatment modality on the hypothalamic-pituitary function of patients treated with radiation therapy for pituitary adenomas: Hypothalamic dose and endocrine outcomes.

    Directory of Open Access Journals (Sweden)

    Andrew eElson

    2014-04-01

    Full Text Available Background: Both fractionated external beam radiotherapy and single fraction radiosurgery for pituitary adenomas are associated with the risk of hypothalamic-pituitary (HP axis dysfunction.Objective: To analyze the effect of treatment modality (Linac, TomoTherapy, or Gamma Knife on hypothalamic dose and correlate these with HP-Axis deficits after radiotherapy.Methods:Radiation plans of patients treated postoperatively for pituitary adenomas using Linac-based 3D Conformal Radiotherapy (CRT (n=11, TomoTherapy-based Intensity Modulated Radiation Therapy (IMRT (n=10, or Gamma Knife Stereotactic Radiosurgery (SRS(n=12 were retrospectively reviewed. Dose to the hypothalamus was analyzed and postradiotherapy hormone function including growth hormone (GH, thyroid (TSH, adrenal (ACTH, prolactin (PRL, and gonadotropins (FSH/LH were assessed. Results:Post-radiation, 13 of 27 (48% patients eligible for analysis developed at least one new hormone deficit, of which 8 of 11 (72% occurred in the Linac group, 4 of 8 (50% occurred in the TomoTherapy group, and 1 of 8 (12.5% occurred in the Gamma Knife group. Compared with fractionated techniques, Gamma Knife showed improved hypothalamic sparing for DMax Hypo, and V12Gy. For fractionated modalities, TomoTherapy showed improved dosimetric characteristics over Linac-based treatment with hypothalamic DMean (44.8 Gy vs. 26.8 Gy p=0.02, DMax (49.8 Gy vs. 39.1 Gy p=0.04, and V12Gy (100% vs. 76% p=0.004.Conclusion:Maximal dosimetric avoidance of the hypothalamus was achieved using Gamma Knife-based radiosurgery followed by TomoTherapy-based IMRT, and Linac-based 3D conformal radiation therapy, respectively.

  18. A simple method for the quality control of the isocenter of cone beam CT for Elekta Accelerator system Synery; Un metodo sencillo para el control de calidad del isocentro del sistema Cone Beam CT para un acelerador Elekta Synery

    Energy Technology Data Exchange (ETDEWEB)

    Clemente Gutierrez, F.; Perez Vara, C.; Prieto Villacorta, M.

    2013-07-01

    Techniques of image-guided radiation therapy has been spreading over the past years. Cone-beam tomography systems constitute a particular case. As any team that employs ionizing radiation in the diagnosis or treatment of patients, such a system must be seen within a guarantee program of quality according to the recommendations and regulations. In particular, between geometric proofs referred to in such a program for these systems, must be referred to the verification of the coincidence between the isocentres of the treatment unit and the team's image. This work includes the weekly procedure followed for such verification. (Author)

  19. Superconductivity in Medicine

    Science.gov (United States)

    Alonso, Jose R.; Antaya, Timothy A.

    2012-01-01

    Superconductivity is playing an increasingly important role in advanced medical technologies. Compact superconducting cyclotrons are emerging as powerful tools for external beam therapy with protons and carbon ions, and offer advantages of cost and size reduction in isotope production as well. Superconducting magnets in isocentric gantries reduce their size and weight to practical proportions. In diagnostic imaging, superconducting magnets have been crucial for the successful clinical implementation of magnetic resonance imaging. This article introduces each of those areas and describes the role which superconductivity is playing in them.

  20. Independent collimators are sufficient to conform and combine adjacent fields?; Os colimadores independentes sao suficientes para conformar e combinar campos adjacentes?

    Energy Technology Data Exchange (ETDEWEB)

    Andrade Neto, Enock de A. [Hospital Sirio Libanes, Sao Paulo, SP (Brazil). Sociedade Beneficente de Senhoras. Servico de Radioterapia; Santos Neto, Geraldo [Grupo COI, Rio de Janeiro, RJ (Brazil). Servico de Radioterapia; Sant' Anna, Marcelo C., E-mail: enock92@gmail.com [RADCLIN Centro de Oncologia, Volta Redonda, RJ (Brazil). Servico de Radioterapia

    2014-12-15

    Consider a radiotherapy treatment in which the tumor is located in the region of head and neck. In general, isocentric technique combined with three tangents half-beam fields are used. How these fields must be collimated? We show that the combination of independent collimators and multi-leaf results in a uniform dose in the region which these fields touch each other. Moreover, we recommend a setup that minimizes the heterogeneity for LINAC's that doesn't possess a multi-leaf collimator. (author)

  1. A treatment planning comparison between modulated tri-cobalt-60 teletherapy and linear accelerator–based stereotactic body radiotherapy for central early-stage non−small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Merna, Catherine; Rwigema, Jean-Claude M.; Cao, Minsong; Wang, Pin-Chieh; Kishan, Amar U.; Michailian, Argin; Lamb, James; Sheng, Ke; Agazaryan, Nzhde; Low, Daniel A.; Kupelian, Patrick; Steinberg, Michael L.; Lee, Percy, E-mail: percylee@mednet.ucla.edu

    2016-04-01

    We evaluated the feasibility of planning stereotactic body radiotherapy (SBRT) for large central early-stage non−small cell lung cancer with a tri-cobalt-60 (tri-{sup 60}Co) system equipped with real-time magnetic resonance imaging (MRI) guidance, as compared to linear accelerator (LINAC)–based SBRT. In all, 20 patients with large central early-stage non−small cell lung cancer who were treated between 2010 and 2015 with LINAC-based SBRT were replanned using a tri-{sup 60}Co system for a prescription dose of 50 Gy in 4 fractions. Doses to organs at risk were evaluated based on established MD Anderson constraints for central lung SBRT. R{sub 100} values were calculated as the total tissue volume receiving 100% of the dose (V{sub 100}) divided by the planning target volume and compared to assess dose conformity. Dosimetric comparisons between LINAC-based and tri-{sup 60}Co SBRT plans were performed using Student's t-test and Wilcoxon Ranks test. Blinded reviews by radiation oncologists were performed to assess the suitability of both plans for clinical delivery. The mean planning target volume was 48.3 cc (range: 12.1 to 139.4 cc). Of the tri-{sup 60}Co SBRT plans, a mean 97.4% of dosimetric parameters per patient met MD Anderson dose constraints, whereas a mean 98.8% of dosimetric parameters per patient were met with LINAC-based SBRT planning (p = 0.056). R{sub 100} values were similar between both plans (1.20 vs 1.21, p = 0.79). Upon blinded review by 4 radiation oncologists, an average of 90% of the tri-{sup 60}Co SBRT plans were considered acceptable for clinical delivery compared with 100% of the corresponding LINAC-based SBRT plans (p = 0.17). SBRT planning using the tri-{sup 60}Co system with built-in MRI is feasible and achieves clinically acceptable plans for most central lung patients, with similar target dose conformity and organ at risk dosimetry. The added benefit of real-time MRI-guided therapy may further optimize tumor targeting while

  2. Plan Quality and Treatment Efficiency for Radiosurgery to Multiple Brain Metastases: Non-Coplanar RapidArc vs. Gamma Knife

    OpenAIRE

    Liu, Haisong; Andrews, David W.; Evans, James J.; Werner-Wasik, Maria; Yan YU; Dicker, Adam Paul; Shi, Wenyin

    2016-01-01

    Objectives This study compares the dosimetry and efficiency of two modern radiosurgery [stereotactic radiosurgery (SRS)] modalities for multiple brain metastases [Gamma Knife (GK) and LINAC-based RapidArc/volumetric modulated arc therapy], with a special focus on the comparison of low-dose spread. Methods Six patients with three or four small brain metastases were used in this study. The size of targets varied from 0.1 to 10.5 cc. SRS doses were prescribed according to the size of ...

  3. Plan Quality and Treatment Efficiency for Radiosurgery to Multiple Brain Metastases: Non-Coplanar RapidArc vs Gamma Knife

    OpenAIRE

    Haisong eLiu; Andrews, David W.; Evans, James J.; Maria eWerner-wasik; Yan eYu; Adam Paul Dicker; Wenyin eShi

    2016-01-01

    Objectives: This study compares the dosimetry and efficiency of two modern radiosurgery (SRS) modalities for multiple brain metastases (Gamma Knife and LINAC-based RapidArc/volumetric modulated arc therapy), with a special focus on the comparison of low dose spread.Methods: Six patients with three or four small brain metastases were used in this study. The size of targets varied from 0.1 ~ 10.5 cc. SRS doses were prescribed according to size of lesions. SRS plans were made using both Gamma Kn...

  4. Simultaneous optimization of the cavity heat load and trip rates in linacs using a genetic algorithm

    Directory of Open Access Journals (Sweden)

    Balša Terzić

    2014-10-01

    Full Text Available In this paper, a genetic algorithm-based optimization is used to simultaneously minimize two competing objectives guiding the operation of the Jefferson Lab’s Continuous Electron Beam Accelerator Facility linacs: cavity heat load and radio frequency cavity trip rates. The results represent a significant improvement to the standard linac energy management tool and thereby could lead to a more efficient Continuous Electron Beam Accelerator Facility configuration. This study also serves as a proof of principle of how a genetic algorithm can be used for optimizing other linac-based machines.

  5. Symposium on electron linear accelerators in honor of Richard B. Neal's 80th birthday: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Siemann, R.H. [ed.

    1998-07-01

    The papers presented at the conference are: (1) the construction of SLAC and the role of R.B. Neal; (2) symposium speech; (3) lessons learned from the SLC; (4) alternate approaches to future electron-positron linear colliders; (5) the NLC technical program; (6) advanced electron linacs; (7) medical uses of linear accelerators; (8) linac-based, intense, coherent X-ray source using self-amplified spontaneous emission. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

  6. Measurement of photoneutron spectrum at Pohang Neutron Facility

    CERN Document Server

    Kim, G N; Lee, Y S; Skoy, V; Cho, M H; Ko, I S; Namkung, W; Lee, D W; Kim, H D; Ko, S K; Park, S H; Kim, D S; Ro, T I; Min, Y G

    2002-01-01

    The Pohang Neutron Facility, an electron linear accelerator (linac) based pulsed neutron facility, was constructed for nuclear data production in Korea. It consists of an electron linac, a water-cooled Ta target with a water moderator, and a time-of-flight path with an 11 m length. The neutron energy spectra are measured for different water levels inside the moderator and compared with calculations by the Monte Carlo N-Particle transport code. The optimum size of the water moderator is determined based on these results.

  7. Ion tracking in photocathode rf guns

    Directory of Open Access Journals (Sweden)

    John W. Lewellen

    2002-02-01

    Full Text Available Projected next-generation linac-based light sources, such as PERL or the TESLA free-electron laser, generally assume, as essential components of their injector complexes, long-pulse photocathode rf electron guns. These guns, due to their design rf pulse durations of many milliseconds to continuous wave, may be more susceptible to ion bombardment damage of their cathodes than conventional rf guns, which typically use rf pulses of microsecond duration. This paper explores this possibility in terms of ion propagation within the gun, and presents a basis for future study of the subject.

  8. Intense ultrashort pulse generation using the JAERI far-infrared free electron laser

    CERN Document Server

    Nagai, R; Nishimori, N; Kikuzawa, N; Sawamura, M; Minehara, E J

    2002-01-01

    An intense ultrashort optical pulse has been quasi-continuously generated using a superconducting RF linac-based free-electron laser at a wavelength of 22.5 mu m. The pulse shape and width are measured by second-order optical autocorrelation with a birefringent Te crystal. At synchronism of the optical resonator, the pulse shape is a smooth single pulse with an FWHM width of 255 fs and energy of 74 mu J. A train of subpulses is developed by increasing the desynchronism of the optical resonator. The measured results are in good agreement with numerical simulation.

  9. The 4th Generation Light Source at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Stephen Benson; George Biallas; James Boyce; Donald Bullard; James Coleman; David Douglas; H. Dylla; Richard Evans; Pavel Evtushenko; Albert Grippo; Christopher Gould; Joseph Gubeli; David Hardy; Carlos Hernandez-Garcia; Kevin Jordan; John Klopf; Steven Moore; George Neil; Thomas Powers; Joseph Preble; Daniel Sexton; Michelle D. Shinn; Christopher Tennant; Richard Walker; Shukui Zhang; Gwyn Williams

    2007-04-25

    A number of "Grand Challenges" in Science have recently been identified in reports from The National Academy of Sciences, and the U.S. Dept. of Energy, Basic Energy Sciences. Many of these require a new generation of linac-based light source to study dynamical and non-linear phenomena in nanoscale samples. In this paper we present a summary of the properties of such light sources, comparing them with existing sources, and then describing in more detail a specific source at Jefferson Lab. Importantly, the JLab light source has developed some novel technology which is a critical enabler for other new light sources.

  10. The optimization of intensity modulated radiotherapy in cases where the planning target volume extends into the build-up region

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, T B; Hoole, A C F; Thomas, S J [Medical Physics Department, Addenbrooke' s Hospital, Hills Road, Cambridge CB2 0QQ (United Kingdom); Burnet, N G [Department of Oncology, University of Cambridge, Oncology Centre (Box 193), Addenbrooke' s Hospital, Hills Road, Cambridge, CB2 0QQ (United Kingdom)], E-mail: binh.nguyen-thai@polytechnique.org

    2009-04-21

    A common clinical problem in IMRT, especially when treating head and neck cases, is that the clinical target volume (CTV) stops short of the skin surface, whilst the margin for geometric uncertainties may take the planning target volume (PTV) to the skin surface or beyond. In these cases, optimization leads to over-dosing of the skin, unless the planner resorts to procedural tricks to avoid this, such as the use of pretend bolus or reduction of the PTV followed by adding 'flash' after optimization. This paper describes a method of avoiding the need for these tricks by using a multiple-isocentre CTV-based objective function. This enables plans to be produced that will give good coverage of the CTV for all the geometrical uncertainties that would have been covered by the PTV without causing the problem of over-dosing the skin. Eight isocentre shifts, equally distributed on the surface of a sphere with a radius equal to the CTV-PTV margin, are shown to be adequate for the optimization process. The resulting fluence maps are much simpler than those resulting from PTV optimization and will therefore be simpler to deliver. The method also permits better sparing of organs at risk such as the spinal cord.

  11. The optimization of intensity modulated radiotherapy in cases where the planning target volume extends into the build-up region

    Science.gov (United States)

    Nguyen, T. B.; Hoole, A. C. F.; Burnet, N. G.; Thomas, S. J.

    2009-04-01

    A common clinical problem in IMRT, especially when treating head and neck cases, is that the clinical target volume (CTV) stops short of the skin surface, whilst the margin for geometric uncertainties may take the planning target volume (PTV) to the skin surface or beyond. In these cases, optimization leads to over-dosing of the skin, unless the planner resorts to procedural tricks to avoid this, such as the use of pretend bolus or reduction of the PTV followed by adding 'flash' after optimization. This paper describes a method of avoiding the need for these tricks by using a multiple-isocentre CTV-based objective function. This enables plans to be produced that will give good coverage of the CTV for all the geometrical uncertainties that would have been covered by the PTV without causing the problem of over-dosing the skin. Eight isocentre shifts, equally distributed on the surface of a sphere with a radius equal to the CTV-PTV margin, are shown to be adequate for the optimization process. The resulting fluence maps are much simpler than those resulting from PTV optimization and will therefore be simpler to deliver. The method also permits better sparing of organs at risk such as the spinal cord.

  12. A comprehensive EPID-based 3D validation technique for TrueBeam-delivered VMAT plans

    Science.gov (United States)

    Ansbacher, W.; Gagne, I. M.; Swift, C.-L.

    2014-03-01

    Purpose: To develop and validate a pre-treatment EPI dosimetry method on Varian TrueBeam linacs using continuous imaging, with reconstruction in a 3D cylindrical phantom geometry. Methods: Delivery of VMAT plans with continuous imaging is currently possible only in Research Mode on TrueBeam linacs, with images acquired in a proprietary format. An earlier technique was adapted to take advantage of technical improvements in EPID delivery, and was tested under various acquisition conditions. The dosimetry of VMAT plans was evaluated at isocentre and within patient volumes that had been transferred to the virtual phantom. Results: Approximately 60 portal image projections per arc were found to be adequate for 3D reconstruction in phantom volumes of 28cm diameter. Twelve prostate, CNS and Head & Neck deliveries were evaluated in Research mode relative to the corresponding Eclipse (v.10) treatment plans, and to measurements on an ArcCheck device in Treatment mode. Mean dose differences at isocentre were within 2% for the three-way comparison, and in PTV volumes were within 1% (s.d. 1%). However, some discrepancies were observed in ArcCheck results that may be related to the small dimensions of certain VMAT apertures. Conclusions: EPI dosimetry with 3D dose reconstruction is an accurate, comprehensive and efficient pre-treatment validation technique for VMAT delivery. Although currently limited to a research mode on TrueBeam, it has the potential to be implemented for clinical use.

  13. Intensity modulation with electrons: calculations, measurements and clinical applications.

    Science.gov (United States)

    Karlsson, M G; Karlsson, M; Zackrisson, B

    1998-05-01

    Intensity modulation of electron beams is one step towards truly conformal therapy. This can be realized with the MM50 racetrack microtron that utilizes a scanning beam technique. By adjusting the scan pattern it is possible to obtain arbitrary fluence distributions. Since the monitor chambers in the treatment head are segmented in both x- and y-directions it is possible to verify the fluence distribution to the patient at any time during the treatment. Intensity modulated electron beams have been measured with film and a plane parallel chamber and compared with calculations. The calculations were based on a pencil beam method. An intensity distribution at the multileaf collimator (MLC) level was calculated by superposition of measured pencil beams over scan patterns. By convolving this distribution with a Gaussian pencil beam, which has propagated from the MLC to the isocentre, a fluence distribution at isocentre level was obtained. The agreement between calculations and measurements was within 2% in dose or 1 mm in distance in the penumbra zones. A standard set of intensity modulated electron beams has been developed. These beams have been implemented in a treatment planning system and are used for manual optimization. A clinical example (prostate) of such an application is presented and compared with a standard irradiation technique.

  14. Intensity modulation with electrons: calculations, measurements and clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Magnus G.; Karlsson, Mikael [Department of Radiation Physics, Umeaa University, S-901 85 Umeaa (Sweden); Zackrisson, Bjoern [Department of Oncology, Umeaa University, S-901 85 Umeaa (Sweden)

    1998-05-01

    Intensity modulation of electron beams is one step towards truly conformal therapy. This can be realized with the MM50 racetrack microtron that utilizes a scanning beam technique. By adjusting the scan pattern it is possible to obtain arbitrary fluence distributions. Since the monitor chambers in the treatment head are segmented in both x- and y-directions it is possible to verify the fluence distribution to the patient at any time during the treatment. Intensity modulated electron beams have been measured with film and a plane parallel chamber and compared with calculations. The calculations were based on a pencil beam method. An intensity distribution at the multileaf collimator (MLC) level was calculated by superposition of measured pencil beams over scan patterns. By convolving this distribution with a Gaussian pencil beam, which has propagated from the MLC to the isocentre, a fluence distribution at isocentre level was obtained. The agreement between calculations and measurements was within 2% in dose or 1 mm in distance in the penumbra zones. A standard set of intensity modulated electron beams has been developed. These beams have been implemented in a treatment planning system and are used for manual optimization. A clinical example (prostate) of such an application is presented and compared with a standard irradiation technique. (author)

  15. Resampling: an optimization method for inverse planning in robotic radiosurgery.

    Science.gov (United States)

    Schweikard, Achim; Schlaefer, Alexander; Adler, John R

    2006-11-01

    By design, the range of beam directions in conventional radiosurgery are constrained to an isocentric array. However, the recent introduction of robotic radiosurgery dramatically increases the flexibility of targeting, and as a consequence, beams need be neither coplanar nor isocentric. Such a nonisocentric design permits a large number of distinct beam directions to be used in one single treatment. These major technical differences provide an opportunity to improve upon the well-established principles for treatment planning used with GammaKnife or LINAC radiosurgery. With this objective in mind, our group has developed over the past decade an inverse planning tool for robotic radiosurgery. This system first computes a set of beam directions, and then during an optimization step, weights each individual beam. Optimization begins with a feasibility query, the answer to which is derived through linear programming. This approach offers the advantage of completeness and avoids local optima. Final beam selection is based on heuristics. In this report we present and evaluate a new strategy for utilizing the advantages of linear programming to improve beam selection. Starting from an initial solution, a heuristically determined set of beams is added to the optimization problem, while beams with zero weight are removed. This process is repeated to sample a set of beams much larger compared with typical optimization. Experimental results indicate that the planning approach efficiently finds acceptable plans and that resampling can further improve its efficiency.

  16. Effects of bone- and air-tissue inhomogeneities on the dose distributions of the Leksell Gamma Knife (registered) calculated with PENELOPE

    Energy Technology Data Exchange (ETDEWEB)

    Al-Dweri, Feras M O [Departamento de Fisica Moderna, Universidad de Granada, E-18071 Granada (Spain); Department of Physics, Applied Science Private University, Amman (Jordan); Rojas, E Leticia [Departamento de Fisica Moderna, Universidad de Granada, E-18071 Granada (Spain); Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca, km 36.5, Ocoyoacac, C.P. 52045 (Mexico); Lallena, Antonio M [Departamento de Fisica Moderna, Universidad de Granada, E-18071 Granada (Spain)

    2005-12-07

    Monte Carlo simulation with PENELOPE (version 2003) is applied to calculate Leksell Gamma Knife (registered) dose distributions for heterogeneous phantoms. The usual spherical water phantom is modified with a spherical bone shell simulating the skull and an air-filled cube simulating the frontal or maxillary sinuses. Different simulations of the 201 source configuration of the Gamma Knife have been carried out with a simplified model of the geometry of the source channel of the Gamma Knife recently tested for both single source and multisource configurations. The dose distributions determined for heterogeneous phantoms including the bone- and/or air-tissue interfaces show non-negligible differences with respect to those calculated for a homogeneous one, mainly when the Gamma Knife isocentre approaches the separation surfaces. Our findings confirm an important underdosage ({approx}10%) nearby the air-tissue interface, in accordance with previous results obtained with the PENELOPE code with a procedure different from ours. On the other hand, the presence of the spherical shell simulating the skull produces a few per cent underdosage at the isocentre wherever it is situated.

  17. An Injector Test Facility for the LCLS

    Energy Technology Data Exchange (ETDEWEB)

    Colby, E., (ed.); /SLAC

    2007-03-14

    SLAC is in the privileged position of being the site for the world's first 4th generation light source as well as having a premier accelerator research staff and facilities. Operation of the world's first x-ray free electron laser (FEL) facility will require innovations in electron injectors to provide electron beams of unprecedented quality. Upgrades to provide ever shorter wavelength x-ray beams of increasing intensity will require significant advances in the state-of-the-art. The BESAC 20-Year Facilities Roadmap identifies the electron gun as ''the critical enabling technology to advance linac-based light sources'' and recognizes that the sources for next-generation light sources are ''the highest-leveraged technology'', and that ''BES should strongly support and coordinate research and development in this unique and critical technology''.[1] This white paper presents an R&D plan and a description of a facility for developing the knowledge and technology required to successfully achieve these upgrades, and to coordinate efforts on short-pulse source development for linac-based light sources.

  18. Perineural spread of cutaneous malignancy to the brain: a review of the literature and five patients treated with stereotactic radiotherapy.

    Science.gov (United States)

    Fowler, B Zach; Crocker, Ian R; Johnstone, Peter A S

    2005-05-15

    The retrospective analysis was performed to investigate the role of stereotactic radiotherapy (SRT) techniques for patients with intracranial perineural spread (PNS) of a primary cutaneous malignancy. Five patients were identified who received SRT from 1993 to 2003 for cutaneous malignancies with intracranial PNS to the cavernous sinus (n = 3) or Meckel's cave (n = 2). Patients were treated with GammaKnife stereotactic radiosurgery (n = 2), linear accelerator (linac)-based fractionated SRT (n = 2), or linac-based stereotactic radiosurgery (n = 1). The median overall survival (OS) periods from diagnoses of cutaneous malignancy and intracranial PNS were 63.0 months (range, 22.0-102.2 months) and 25.5 months (range, 22.0-55.2 months), respectively. The median OS from SRT was 24.2 months (range, 19.5-53.2 months). One patient was alive and without evidence of disease at 53 months of follow-up. The median durations of local and regional control from SRT were 19.5 months (range, 1.5-53.2 months) and 7.0 months (range, 1.5-53.2 months), respectively. Previous reports generally have recommended that patients with intracranial PNS receive palliative external-beam radiotherapy. Results from the current study suggest that some of these patients may have prolonged survival, or even may be cured. Judicious use of SRT should be considered in their management.

  19. Data quality management system (DQMS) for BAC detector in the ZEUS experiment at the HERA accelerator

    Science.gov (United States)

    Luszczak, Zbigniew; Jezynski, Tomasz; Romaniuk, Ryszard S.; Pozniak, Krzysztof T.; Kuthan, Marcin; Bigos, Grzegorz; Gierej, Artur

    2003-10-01

    The paper presents functional structure of database system of data measurement quality for BAC detector in ZEUS experiment. The system collects diagnostic and experimental data. Diagnostic data are: work parameters of the detector and electronics/photonics, tests of electronic/photonic blocks. These data are archived for certain period of time. The quality of current data collection process is estimated using these archived data. The result of such estimation is generated in a form of status map of the detector. Such maps, describing status of the hardware, are fundamental for elementary particle analysis by the calorimeter. The DAQ system, collecting data to the database, estimates data quality on-line during transmission and writing. This mechanism of fast on-line data quality management leads to early discoveries of detector work irregularities and faults.

  20. Highly sensitive visible-blind extreme ultraviolet Ni/4H-SiC Schottky photodiodes with large detection area.

    Science.gov (United States)

    Hu, Jun; Xin, Xiaobin; Zhao, Jian H; Yan, Feng; Guan, Bing; Seely, John; Kjornrattanawanich, Benjawan

    2006-06-01

    Ni/4H-SiC Schottky photodiodes of 5 mm x 5 mm area have been fabricated and characterized. The photodiodes show less than 0.1 pA dark current at -4 V and an ideality factor of 1.06. A quantum efficiency (QE) between 3 and 400 nm has been calibrated and compared with Si photodiodes optimized for extreme ultraviolet (EUV) detection. In the EUV region, the QE of SiC detectors increases from 0.14 electrons/photon at 120 nm to 30 electrons/photon at 3 nm. The mean energy of electron-hole pair generation of 4H-SiC estimated from the spectral QE is found to be 7.9 eV.

  1. Topics in gauge theories and the unification of elementary particle interactions. Progress report, February 1, 1993--January 31, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Y.N.; Vaughn, M.T.

    1994-02-01

    We report on work done by the principal investigators (Y.N. Srivastava and M.T. Vaughn) and their collaborators on (1) Interference Between Past and Future Events in Neutral Kaon Decays in {Phi} {yields} K{bar K}; (2) Single Top Production at LEP II and at Electron -- Photon Colliders; (3) Renormahzation Group Studies of Unified Gauge Theories; (4) Analysis of Classical Field Theories; and (5) Quantum Effects of Strong Classical Electromagnetic Fields.

  2. Single-chip microprocessor that communicates directly using light.

    Science.gov (United States)

    Sun, Chen; Wade, Mark T; Lee, Yunsup; Orcutt, Jason S; Alloatti, Luca; Georgas, Michael S; Waterman, Andrew S; Shainline, Jeffrey M; Avizienis, Rimas R; Lin, Sen; Moss, Benjamin R; Kumar, Rajesh; Pavanello, Fabio; Atabaki, Amir H; Cook, Henry M; Ou, Albert J; Leu, Jonathan C; Chen, Yu-Hsin; Asanović, Krste; Ram, Rajeev J; Popović, Miloš A; Stojanović, Vladimir M

    2015-12-24

    Data transport across short electrical wires is limited by both bandwidth and power density, which creates a performance bottleneck for semiconductor microchips in modern computer systems--from mobile phones to large-scale data centres. These limitations can be overcome by using optical communications based on chip-scale electronic-photonic systems enabled by silicon-based nanophotonic devices. However, combining electronics and photonics on the same chip has proved challenging, owing to microchip manufacturing conflicts between electronics and photonics. Consequently, current electronic-photonic chips are limited to niche manufacturing processes and include only a few optical devices alongside simple circuits. Here we report an electronic-photonic system on a single chip integrating over 70 million transistors and 850 photonic components that work together to provide logic, memory, and interconnect functions. This system is a realization of a microprocessor that uses on-chip photonic devices to directly communicate with other chips using light. To integrate electronics and photonics at the scale of a microprocessor chip, we adopt a 'zero-change' approach to the integration of photonics. Instead of developing a custom process to enable the fabrication of photonics, which would complicate or eliminate the possibility of integration with state-of-the-art transistors at large scale and at high yield, we design optical devices using a standard microelectronics foundry process that is used for modern microprocessors. This demonstration could represent the beginning of an era of chip-scale electronic-photonic systems with the potential to transform computing system architectures, enabling more powerful computers, from network infrastructure to data centres and supercomputers.

  3. Photoneutron production in tungsten, praseodymium, copper and beryllium by using high energy electron linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Jallu, F. E-mail: jalluf@macadam.cea.fr; Lyoussi, A.; Payan, E.; Recroix, H.; Mariani, A.; Nurdin, G.; Buisson, A.; Allano, J

    1999-09-01

    This paper presents comparisons between photoneutron production measurements in tungsten, copper, praseodymium and beryllium, and calculated data resulting from the ELEPHANT (ELEctron, PHoton And Neutron Transport) code. Measurements were made using the DGA/ETCA linear electron accelerator located at Arcueil, France. Bremsstrahlung endpoints varying in the 15-25 MeV energy range were used. Detectors were positioned at different angles with respect to the electron beam axis. Each measured value is compared with the corresponding calculated value.

  4. ATLAS experiment - Episode 2 - The Particles Strike Back

    CERN Multimedia

    Michael Barnett - Erik Johansson

    2006-01-01

    ATLAS, The Particles Strike Back is the second episode in a three part series that uncovers the mysteries of the ATLAS experiment. Shot with a bug's eye view of the inside of the detector. The viewer is shown the inner, middle and outer sections of the ATLAS detector. The narrator describes how different parts of the detector are able to detect 6 different types of particles: electrons, photons, protons, neutrons, muons and neutrinos.

  5. Elastically Decoupling Dark Matter

    CERN Document Server

    Kuflik, Eric; Lorier, Nicolas Rey-Le; Tsai, Yu-Dai

    2015-01-01

    We present a novel dark matter candidate, an Elastically Decoupling Relic (ELDER), which is a cold thermal relic whose present abundance is determined by the cross-section of its elastic scattering on Standard Model particles. The dark matter candidate is predicted to have a mass ranging from a few to a few hundred MeV, and an elastic scattering cross-section with electrons, photons and/or neutrinos in the $10^{-3}-1$ fb range.

  6. Exceptional-point Dynamics in Photonic Honeycomb Lattices with PT Symmetry

    Science.gov (United States)

    2012-01-17

    including the existence of diabolical points, with the band structure of graphene in condensed matter physics literature. In graphene , the electrons...photonic and electronic graphene structures allow us to test experimentally various legendary predictions of relativistic quantum mechanics such as...with the mod- ulation of the index of refraction, to achieve new classes of synthetic metamaterials that can give rise to altogether new physical

  7. Performance of the ATLAS Calorimeters using Cosmic Ray Muons

    OpenAIRE

    Santoni, C.

    2010-01-01

    International audience; The ATLAS calorimeters provide precision measurements of electrons, photons, jets and missing transverse energy produced in the LHC proton-proton collisions. High granularity liquid-argon electromagnetic and hadronic sampling calorimeters are used. An iron-scintillator hadronic calorimeter surrounds the liquid-argon detectors. Results assessing the calorimeter performance obtained using cosmic ray muons are presented. The non-uniformity of the barrel electromagnetic ca...

  8. Monolithically Integrated Ge-on-Si Active Photonics

    OpenAIRE

    Jifeng Liu

    2014-01-01

    Monolithically integrated, active photonic devices on Si are key components in Si-based large-scale electronic-photonic integration for future generations of high-performance, low-power computation and communication systems. Ge has become an interesting candidate for active photonic devices in Si photonics due to its pseudo-direct gap behavior and compatibility with Si complementary metal oxide semiconductor (CMOS) processing. In this paper, we present a review of the recent progress in Ge-on...

  9. Automated Monte Carlo biasing for photon-generated electrons near surfaces.

    Energy Technology Data Exchange (ETDEWEB)

    Franke, Brian Claude; Crawford, Martin James; Kensek, Ronald Patrick

    2009-09-01

    This report describes efforts to automate the biasing of coupled electron-photon Monte Carlo particle transport calculations. The approach was based on weight-windows biasing. Weight-window settings were determined using adjoint-flux Monte Carlo calculations. A variety of algorithms were investigated for adaptivity of the Monte Carlo tallies. Tree data structures were used to investigate spatial partitioning. Functional-expansion tallies were used to investigate higher-order spatial representations.

  10. Stabilizing Semiconductor Devices With Hydrogen

    Science.gov (United States)

    Overhauser, Albert W.; Maserjian, Joseph

    1989-01-01

    Damage by radiation healed rapidly. Feature provides continuous, rapid recovery of devices from degradation caused by hot electrons, photons, and ionizing radiation. Several candidate sites for palladium film catalysts, inserted during manufacture as integral parts of devices. Paladium films made by evaporation, sputtering, or chemical-vapor deposition. If additional storage required, thick layer of palladium plated on inside of package surrounding device. Hydrogen stored by exposing palladium to hydrogen gas just before package sealed hermetically.

  11. Elastically Decoupling Dark Matter.

    Science.gov (United States)

    Kuflik, Eric; Perelstein, Maxim; Lorier, Nicolas Rey-Le; Tsai, Yu-Dai

    2016-06-03

    We present a novel dark matter candidate, an elastically decoupling relic, which is a cold thermal relic whose present abundance is determined by the cross section of its elastic scattering on standard model particles. The dark matter candidate is predicted to have a mass ranging from a few to a few hundred MeV, and an elastic scattering cross section with electrons, photons and/or neutrinos in the 10^{-3}-1  fb range.

  12. Single-chip microprocessor that communicates directly using light

    Science.gov (United States)

    Sun, Chen; Wade, Mark T.; Lee, Yunsup; Orcutt, Jason S.; Alloatti, Luca; Georgas, Michael S.; Waterman, Andrew S.; Shainline, Jeffrey M.; Avizienis, Rimas R.; Lin, Sen; Moss, Benjamin R.; Kumar, Rajesh; Pavanello, Fabio; Atabaki, Amir H.; Cook, Henry M.; Ou, Albert J.; Leu, Jonathan C.; Chen, Yu-Hsin; Asanović, Krste; Ram, Rajeev J.; Popović, Miloš A.; Stojanović, Vladimir M.

    2015-12-01

    Data transport across short electrical wires is limited by both bandwidth and power density, which creates a performance bottleneck for semiconductor microchips in modern computer systems—from mobile phones to large-scale data centres. These limitations can be overcome by using optical communications based on chip-scale electronic-photonic systems enabled by silicon-based nanophotonic devices8. However, combining electronics and photonics on the same chip has proved challenging, owing to microchip manufacturing conflicts between electronics and photonics. Consequently, current electronic-photonic chips are limited to niche manufacturing processes and include only a few optical devices alongside simple circuits. Here we report an electronic-photonic system on a single chip integrating over 70 million transistors and 850 photonic components that work together to provide logic, memory, and interconnect functions. This system is a realization of a microprocessor that uses on-chip photonic devices to directly communicate with other chips using light. To integrate electronics and photonics at the scale of a microprocessor chip, we adopt a ‘zero-change’ approach to the integration of photonics. Instead of developing a custom process to enable the fabrication of photonics, which would complicate or eliminate the possibility of integration with state-of-the-art transistors at large scale and at high yield, we design optical devices using a standard microelectronics foundry process that is used for modern microprocessors. This demonstration could represent the beginning of an era of chip-scale electronic-photonic systems with the potential to transform computing system architectures, enabling more powerful computers, from network infrastructure to data centres and supercomputers.

  13. Revealing the Anisotropic Thermal Conductivity of Black Phosphorus using the Time-Resolved Magneto-Optical Kerr Effect

    OpenAIRE

    Zhu, Jie; Park, Haechan; Chen, Jun-Yang; Gu, Xiaokun; Zhang, Hu; Karthikeyan, Sreejith; Wendel, Nathaniel; Campbell, Stephen A.; Dawber, Matthew; Du, Xu; Li, Mo; Wang, Jian-Ping; Yang, Ronggui; Wang, Xiaojia

    2015-01-01

    Black phosphorus (BP) has emerged as a direct-bandgap semiconducting material with great application potentials in electronics, photonics, and energy conversion. Experimental characterization of the anisotropic thermal properties of BP, however, is extremely challenging due to the lack of reliable and accurate measurement techniques to characterize anisotropic samples that are micrometers in size. Here, we report measurement results of the anisotropic thermal conductivity of bulk BP along thr...

  14. A study of Winston-Lutz test on two different electronic portal imaging devices and with low energy imaging.

    Science.gov (United States)

    Ravindran, Paul B

    2016-09-01

    Stereotactic radiosurgery requires sub-millimetre accuracy in patient positioning and target localization. Therefore, verification of the linear accelerator (linac) isocentre and the laser alignment to the isocentre is performed in some clinics prior to the treatment using the Winston-Lutz (W-L) test with films and more recently with images obtained using the electronic portal imaging devices (EPID). The W-L test is performed by acquiring EPID images of a radio-opaque ball of 6 mm diameter (the W-L phantom) placed at the isocentre of the linac at various gantry and table angles, with a predefined small square or circular radiation beam. In this study, the W-L test was performed on two linacs having EPIDs of different size and resolution, viz, a TrueBeam™ linac with aS1000 EPID of size 40 × 30 cm(2) with 1024 × 768 pixel resolution and an EDGE™ linac having an EPID of size 43 × 43 cm(2) with pixel resolution of 1280 × 1280. In order to determine the displacement of the radio-opaque ball centre from the radiation beam centre of the W-L test, an in-house MATLAB™ image processing code was developed using morphological operations. The displacement in radiation beam centre at each gantry and couch position was obtained by determining the distance between the radiation field centre and the radio-opaque ball centre for every image. Since the MATLAB code was based on image processing that was dependent on the image contrast and resolution, the W-L test was also compared for images obtained with different beam energies. The W-L tests were performed for 6 and 8 MV beams on the TrueBeam™ linac and for 2.5 and 6 MV beams on the EDGE™ linac with a higher resolution EPID. It was observed that the images obtained with the EPID of higher resolution resulted in same accuracy in the determination of the displacement between the centres of the radio-opaque ball and the radiation beam, and significant difference was not observed with images acquired with

  15. Quality assurance of a conformal treatment technique

    Energy Technology Data Exchange (ETDEWEB)

    Kroes, A.P.G.; Bruinvis, I.A.D.; Lanson, J.H.; Uiterwaal, G.J. [Nederlands Kanker Inst. `Antoni van Leeuwenhoekhuis`, Amsterdam (Netherlands)

    1995-12-01

    For a parotid gland irradiation technique with a pair of oblique wedged photon beams the target coverage near the surface was investigated. The planning target volume extends to 5 millimetres under the skin; a minimum target dose of 95% is required when the dose at the centre is set to 100%. The treatment technique was simulated on a water phantom with a beam of 45 degree gantry angle, 55 degree wedge, 8 x 10 cm{sup 2} field size and the isocentre at 2 cm depth. Beam energies of 4, 6 and 8 MV were used. The dose distributions were measured in two orthogonal planes through the isocentre perpendicular to the water surface with p-type silicon diodes along lines through the isocentre every 45 degrees. Dose distributions were calculated in these planes with our 3-D planning system (U-Mplan, University of Michigan planning system), with model parameters are fitted to depth dose curves and profiles of open and wedged normally incident beams. The location of the 95% isodose was determined in five points near the surface. For 4, 6 and 8 MV the depths of the 95% isodose were 6.0, 10.3 and 11.0 mm, respectively. The depths of the 95% points of single normally incident open fields were 6.0, 9.0 and 11.5 mm, respectively. The treatment planning system (TPS) calculated the 95% isodose for the parotid technique at 5.5, 7.3 and 11.5 mm depths, for 4, 6 and 8 MV, respectively. Thus for 6 MV the 95% was 3 mm deeper than calculated by the TPS; 2 mm were caused by the inaccuracy of the open field depth dose curve fit in the build-up region. The depth near the surface of the 95% isodose for this treatment technique can be estimated from single open field depth dose curves with acceptable accuracy. This result is not obvious because the effects of the wedge and oblique incidence on the dose distribution are also involved. The TPS performed well for the 4 and 8 MV beams, but for treatments with 6 MV target under dosage could have remained undetected. (Abstract Truncated)

  16. ELECTRON BEAM ION SOURCE PREINJECTOR PROJECT (EBIS) CONCEPTUAL DESIGN REPORT.

    Energy Technology Data Exchange (ETDEWEB)

    ALESSI, J.; BARTON, D.; BEEBE, E.; GASSNER, D.; GRANDINETTI, R.; HSEUH, H.; JAVIDFAR, A.; KPONOU, A.; LAMBIASE, R.; LESSARD, E.; LOCKEY, R.; LODESTRO, V.; MAPES, M.; MIRABELLA, D.; NEHRING, T.; OERTER, B.; PENDZICK, A.; PIKIN, A.; RAPARIA, D.; RITTER, J.; ROSER, T.; RUSSO, T.; SNYDSTRUP, L.; WILINSKI, M.; ZALTSMAN, A.; ZHANG, S.

    2005-09-01

    This report describes a new heavy ion pre-injector for the Relativistic Heavy Ion Collider (RHIC) based on a high charge state Electron Beam Ion Source (EBIS), a Radio Frequency Quadrupole (RFQ) accelerator, and a short Linear accelerator (Linac). The highly successful development of an EBIS at Brookhaven National Laboratory (BNL) now makes it possible to replace the present pre-injector that is based on an electrostatic Tandem with a reliable, low maintenance Linac-based pre-injector. Linac-based preinjectors are presently used at most accelerator and collider facilities with the exception of RHIC, where the required gold beam intensities could only be met with a Tandem until the recent EBIS development. EBIS produces high charge state ions directly, eliminating the need for the two stripping foils presently used with the Tandem. Unstable stripping efficiencies of these foils are a significant source of luminosity degradation in RHIC. The high reliability and flexibility of the new Linac-based pre-injector will lead to increased integrated luminosity at RHIC and is an essential component for the long-term success of the RHIC facility. This new pre-injector, based on an EBIS, also has the potential for significant future intensity increases and can produce heavy ion beams of all species including uranium beams and, as part of a future upgrade, might also be used to produce polarized {sup 3}He beams. These capabilities will be critical to the future luminosity upgrades and electron-ion collisions in RHIC. The proposed pre-injector system would also provide for a major enhancement in capability for the NASA Space Radiation Laboratory (NSRL), which utilizes heavy-ion beams from the RHIC complex. EBIS would allow for the acceleration of all important ion species for the NASA radiobiology program, such as, helium, argon, and neon which are unavailable with the present Tandem injector. In addition, the new system would allow for very rapid switching of ion species for

  17. In vivo dosimetry during pelvic treatment

    Energy Technology Data Exchange (ETDEWEB)

    Heukelom, S.; Lanson, J.H.; Mijnheer, B.J. (Nederlands Kanker Inst. ' Antoni van Leeuwenhoekhuis' , Amsterdam (Netherlands))

    1992-10-01

    High precision in vivo entrance and exit dose measurements have been performed with p-type diodes on patients during 8 MV X-ray irradiation of the pelvis, to investigate the accuracy of dose calculations in this region. Based on phantom measurements the accuracy of the p-type diode measuring system itself, i.e. the agreement with ionization chamber dose measurement, was shown to be better than 0.7% while the reproducibility in the dose determination was 1.1%, 1.5% and 1.6% (1 S.D.) at the entrance point, isocentre and exit point, respectively, for the wedged lateral fields. (author). 23 refs., 5 figs., 2 tabs.

  18. The South African National Accelerator Centre: particle therapy and isotope production programmes

    Science.gov (United States)

    Jones, D. T. L.; Mills, S. J.

    1998-06-01

    The National Accelerator Centre (NAC) provides facilities for basic and applied research, radioisotope production and particle therapy. To date, 851 patients have been treated on the 66 MeV p+Be isocentric neutron therapy unit while 191 patients have been treated (mainly for intracranial conditions) on the 200 MeV horizontal proton beam facility. A variety of radioisotopes such as 67Ga, 81Rb/ 81Kr, 111In, 123I, and 201Tl are produced on a regular weekly basis, and more than 1000 consignments of radiopharmaceuticals prepared from these radioisotopes are supplied to more than 30 hospitals and private practices throughout South Africa each year. Some non-medical radioisotopes are also produced.

  19. The direct measurement using an imaging plate for coincidence of radiation centre and laser position in external radiation therapy.

    Science.gov (United States)

    Terunuma, Toshiyuki; Sakae, Takeji; Nohtomi, Akihiro; Tsunashima, Yoshikazu

    2003-02-21

    A new method of quality assurance has been studied to measure coincidence of the radiation centre and a patient-setup laser position on a transverse plane to the beam at the isocentre. This measurement is achieved by using an imaging plate (IP). When radiation is applied to an IP, the energy is stored as trapped electrons. The number of electrons is decreased by local laser exposure. As a result, the radiation field produced by external beam irradiation is recorded as 'positive' information and the position of the patient-setup laser is recorded as 'negative' on an IP. The advantages of this method are the direct measurement, short time and high resolution. These are required for daily and monthly quality checks. We confirmed the advantage of this method by an experiment using a proton beam.

  20. The Italian project for a hadrontherapy centre

    Energy Technology Data Exchange (ETDEWEB)

    Amaldi, U. [European Organization for Nuclear Research, Geneva (Switzerland)]|[Universita di Milano, Como Seat, Via Lucini 3, 22100 Como (Italy); Arduini, G. [ASP, Villa Gualino, Via Settimio Severo 65, 10133 Torino (Italy); Badano, L. [Fondazione per Adroterapia Oncologica, Via Puccini 11, 28100 Novara (Italy); Cambria, R. [Fondazione per Adroterapia Oncologica, Via Puccini 11, 28100 Novara (Italy); Campi, D. [European Organization for Nuclear Research, Geneva (Switzerland); Gerardi, F. [Fondazione Italiana Ricerca sul Cancro, Via F. Corridoni 7, 20122 Milano (Italy); Gramatica, F. [Fondazione per Adroterapia Oncologica, Via Puccini 11, 28100 Novara (Italy); Leone, R. [Fondazione Italiana Ricerca sul Cancro, Via F. Corridoni 7, 20122 Milano (Italy); Manfredi, G. [Consiglio Nazionale delle Ricerche, ITBA, Via Ampere 56, 20131 Milano (Italy); Nonis, M. [Fondazione per Adroterapia Oncologica, Via Puccini 11, 28100 Novara (Italy); Pullia, M. [Fondazione per Adroterapia Oncologica, Via Puccini 11, 28100 Novara (Italy); Rossi, S. [Fondazione per Adroterapia Oncologica, Via Puccini 11, 28100 Novara (Italy); Sangaletti, L. [Fondazione Italiana Ricerca sul Cancro, Via F. Corridoni 7, 20122 Milano (Italy); Silari, M. [Consiglio Nazionale delle Ricerche, ITBA, Via Ampere 56, 20131 Milano (Italy); Tosi, G. [Fondazione per Adroterapia Oncologica, Via Puccini 11, 28100 Novara (Italy)]|[Istituto Europeo di Oncologia, Via Ripamonti 435, 22100 Milano (Italy)

    1995-06-01

    A feasibility study has just been completed for a hospital-based hadrontherapy facility to be built in Italy. This facility aims at the treatment of 1000 patients/year in 5 treatment rooms served by a H{sup -}/light ion synchrotron producing proton beams with energies ranging from 60 to 250 MeV. Generation of neutron beams for boron neutron capture therapy and production of positron emitting radionuclides for PET diagnostics is also foreseen. After an account of the rationale for the use of hadron beams in radiation therapy, a brief overview is given of both the technical components and the facility layout. Two of the treatment rooms will be equipped with a rotating isocentric irradiation unit. The design foresees the possibility of implementing, as a future development, acceleration of fully stripped light ions up to {sup 16}O to energies in the 120-400 MeV/u range. (orig.).

  1. Characterization of an add-on multileaf collimator for electron beam therapy

    Science.gov (United States)

    Gauer, T.; Sokoll, J.; Cremers, F.; Harmansa, R.; Luzzara, M.; Schmidt, R.

    2008-02-01

    An add-on multileaf collimator for electrons (eMLC) has been developed that provides computer-controlled beam collimation and isocentric dose delivery. The design parameters result from the design study by Gauer et al (2006 Phys. Med. Biol. 51 5987-6003) and were configured such that a compact and light-weight eMLC with motorized leaves can be industrially manufactured and stably mounted on a conventional linear accelerator. In the present study, the efficiency of an initial computer-controlled prototype was examined according to the design goals and the performance of energy- and intensity-modulated treatment techniques. This study concentrates on the attachment and gantry stability as well as the dosimetric characteristics of central-axis and off-axis dose, field size dependence, collimator scatter, field abutment, radiation leakage and the setting of the accelerator jaws. To provide isocentric irradiation, the eMLC can be placed either 16 or 28 cm above the isocentre through interchangeable holders. The mechanical implementation of this feature results in a maximum field displacement of less than 0.6 mm at 90° and 270° gantry angles. Compared to a 10 × 10 cm applicator at 6-14 MeV, the beam penumbra of the eMLC at a 16 cm collimator-to-isocentre distance is 0.8-0.4 cm greater and the depth-dose curves show a larger build-up effect. Due to the loss in energy dependence of the therapeutic range and the much lower dose output at small beam sizes, a minimum beam size of 3 × 3 cm is necessary to avoid suboptimal dose delivery. Dose output and beam symmetry are not affected by collimator scatter when the central axis is blocked. As a consequence of the broader beam penumbra, uniform dose distributions were measured in the junction region of adjacent beams at perpendicular and oblique beam incidence. However, adjacent beams with a high difference in a beam energy of 6 to 14 MeV generate cold and hot spots of approximately 15% in the abutting region. In order to

  2. Total body irradiation with a reconditioned cobalt teletherapy unit.

    Science.gov (United States)

    Evans, Michael D C; Larouche, Renée-Xavière; Olivares, Marina; Léger, Pierre; Larkin, Joe; Freeman, Carolyn R; Podgorsak, Ervin B

    2006-01-01

    While the current trend in radiotherapy is to replace cobalt teletherapy units with more versatile and technologically advanced linear accelerators, there remain some useful applications for older cobalt units. The expansion of our radiotherapy department involved the decommissioning of an isocentric cobalt teletherapy unit and the replacement of a column-mounted 4-MV LINAC that has been used for total body irradiation (TBI). To continue offering TBI treatments, we converted the decommissioned cobalt unit into a dedicated fixed-field total body irradiator and installed it in an existing medium-energy LINAC bunker. This article describes the logistical and dosimetric aspects of bringing a reconditioned cobalt teletherapy unit into clinical service as a total body irradiator.

  3. Radiosurgery with high energy photon beams: a comparison among techniques

    Energy Technology Data Exchange (ETDEWEB)

    Podgorsak, E.B.; Pike, G.B.; Olivier, A.; Pla, M.; Souhami, L.

    1989-03-01

    The presently known radiosurgical techniques with high energy photon beams are based either on the commercially available Gamma unit utilizing 201 stationary cobalt beams or on isocentric linear accelerators. The techniques using linear accelerators are divided into the single plane rotation, the multiple non-coplanar arcs, and the dynamic rotation. A brief description of these techniques is given, and their physical characteristics, such as precision of dose delivery, dose fall-off outside the target volume, and isodose distributions are discussed. It is shown that the multiple non-coplanar arcs technique and the dynamic rotation give dose distributions similar to those of the Gamma unit, which makes these two linear accelerator based techniques attractive alternatives to radiosurgery with the Gamma unit.22 references.

  4. Three-dimensional Intraoperative Imaging Modalities in Orthopaedic Surgery: A Narrative Review.

    Science.gov (United States)

    Qureshi, Sheeraz; Lu, Young; McAnany, Steven; Baird, Evan

    2014-12-01

    Intraoperative imaging and navigation systems have revolutionized orthopaedic surgery for the spine, joints, and orthopaedic trauma. Imaging modalities such as the isocentric C-arm, O-arm imaging, and intraoperative MRI or navigation systems allow the visualization of surgical instruments and implants relative to a three-dimensional CT image or MRI. Studies show that these technologies lower the rates of implant misplacement and inadequate fracture reduction, thereby improving surgical outcomes and reducing reoperation rates. An additional benefit is reduced radiation exposure compared with that for conventional fluoroscopy. Concerns surrounding adoption of these technologies include cost and increased operating times, but improvements in design and protocol may improve the integration of these imaging modalities into the operating room.

  5. Sensor-based hip control with hybrid neuroprosthesis for walking in paraplegia.

    Science.gov (United States)

    To, Curtis S; Kobetic, Rudi; Bulea, Thomas C; Audu, Musa L; Schnellenberger, John R; Pinault, Gilles; Triolo, Ronald J

    2014-01-01

    The objectives of this study were to test whether a hybrid neuroprosthesis (HNP) with an exoskeletal variable-constraint hip mechanism (VCHM) combined with a functional neuromuscular stimulation (FNS) controller can maintain upright posture with less upper-limb support and improve gait speed as compared with walking with either an isocentric reciprocating gait orthosis (IRGO) or FNS only. The results show that walking with the HNP significantly reduced forward lean in FNS-only walking and the maximum upper-limb forces by 42% and 19% as compared with the IRGO and FNS-only gait, respectively. Walking speed increased significantly with VCHM as compared with 1:1 reciprocal coupling and by 15% when using the sensor-based FNS controller as compared with HNP with fixed baseline stimulation without the controller active.

  6. Sensor-based hip control with hybrid neuroprosthesis for walking in paraplegia

    Directory of Open Access Journals (Sweden)

    Curtis S. To, PhD

    2014-03-01

    Full Text Available The objectives of this study were to test whether a hybrid neuroprosthesis (HNP with an exoskeletal variable-­constraint hip mechanism (VCHM combined with a functional neuromuscular stimulation (FNS controller can maintain upright posture with less upper-limb support and improve gait speed as compared with walking with either an isocentric reciprocating gait orthosis (IRGO or FNS only. The results show that walking with the HNP significantly reduced forward lean in FNS-only walking and the maximum upper-limb forces by 42% and 19% as compared with the IRGO and FNS-only gait, respectively. Walking speed increased significantly with VCHM as compared with 1:1 reciprocal coupling and by 15% when using the sensor-based FNS controller as compared with HNP with fixed baseline stimulation without the controller active.

  7. LiTrack A Fast longitudinal phase space tracking code with graphical user interface

    CERN Document Server

    Emma, Paul

    2005-01-01

    Many linear accelerators, such as linac-based light sources and linear colliders, apply longitudinal phase space manipulations in their design, including electron bunch compression and wakefield-induced energy spread control. Several computer codes handle such issues, but most require detailed information on the transverse focusing lattice. In fact, in most linear accelerators, the transverse distributions do not significantly affect the longitudinal, and can be ignored initially. This allows the use of a fast 2D code to study longitudinal aspects without time-consuming considerations of the transverse focusing. LiTrack is based on a 15-year old code (same name) originally written by one of us (KB), which is now a MATLAB-based code with additional features, such as a graphical user interface and output plotting. The single-bunch tracking includes RF acceleration, bunch compression to 3rd order, geometric and resistive wakefields, aperture limits, synchrotron radiation, and flexible output plotting. The code w...

  8. Summary report of working group 2 on {open_quotes}Beam Production{close_quotes}

    Energy Technology Data Exchange (ETDEWEB)

    Serafini, Luca [INFN and Universita di Milano Via Celoria 16, 20133Milano (Italy)] Cornacchia, Max [SSRL---Stanford Linear Accelerator Center, Stanford, California94309 (United States)

    1997-06-01

    We summarize here the discussions and the communications presented in the working group on {open_quotes}Beam Production{close_quotes}, whose main aim was actually focused on identification of main processes limiting the maximum achievable electron beam brightness at injection into the undulator of a generic linac-based X-Ray single pass FEL. These processes have been divided into three main categories: stochastic effects in the photoelectric emission at the cathode, emittance degradation due to space charge effects in the injector, coherent spontaneous emission in bends ({ital e.g.} magnetic compressors) and its related impact on the emittance and/or peak current budget. {copyright} {ital 1997 American Institute of Physics.}

  9. Ultrafast Science Opportunities with Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    DURR, HERMANN; Wang, X.J., ed.

    2016-04-28

    X-rays and electrons are two of the most fundamental probes of matter. When the Linac Coherent Light Source (LCLS), the world’s first x-ray free electron laser, began operation in 2009, it transformed ultrafast science with the ability to generate laser-like x-ray pulses from the manipulation of relativistic electron beams. This document describes a similar future transformation. In Transmission Electron Microscopy, ultrafast relativistic (MeV energy) electron pulses can achieve unsurpassed spatial and temporal resolution. Ultrafast temporal resolution will be the next frontier in electron microscopy and can ideally complement ultrafast x-ray science done with free electron lasers. This document describes the Grand Challenge science opportunities in chemistry, material science, physics and biology that arise from an MeV ultrafast electron diffraction & microscopy facility, especially when coupled with linac-based intense THz and X-ray pump capabilities.

  10. Hie-Isolde High Beta Cavity Study and Measurements

    CERN Document Server

    D'Elia, A; Pasini, M

    2009-01-01

    The upgrade of the ISOLDE machine at CERN foresees a superconducting linac based on two gap independently phased Nb sputtered Quarter Wave Resonators (QWRs) working at 101.28MHz and producing an accelerating field of 6MV/m on axis. A careful study of the fields in the cavity has been carried out in order to pin down the crucial e-m parameters of the structure such as peak fields, quality factor and e-m power dissipated on the cavity wall. A tuning system with about 200kHz frequency range has been developed in order to cope with fabrication tolerances. In this paper we will report on the cavity simulations. The tuning plate design will be described. Finally the frequency measurements on a cavity prototype at room temperature will be presented.

  11. Reference Physics Design for 1 GeV Injector Linac and Accumulator Ring for Indian Spallation Neutron Source

    CERN Document Server

    Sharma, Amalendu; Patidar, Chirag Bhai; Pal, Mukesh Kumar; Kulkarni, Nita; Goyal, Pradeep Kumar; Jana, Prasanta Kumar; Gaur, Rahul; Prakash, Ram; Dhingra, Rinky; Singh, Urmila; Kumar, Vinit

    2016-01-01

    As a part of the ongoing plan project titled 'R&D activities for high energy proton linac based spallation neutron source', the work on physics design of various subsystems of the injector linac and accumulator ring has been taken up. For the 1 GeV H- injector linac, physics design studies of individual systems have been completed, and the end to end beam dynamics simulation studies have been performed to ensure that the stringent beam dynamics criteria are satisfied for the optimized lattice. Physics design studies to optimize the linear lattice of the accumulator ring have also been completed. The design studies for the beam transport lines from the injector linac to the accumulator ring, and from the accumulator ring to target are currently in progress. This report describes the physics design of various systems of the injector linac and the accumulator ring.

  12. Compact Electron-Linac Design Concept for a Gamma Ray Source

    CERN Document Server

    Chan, K C D; Dale, G; Garnett, R; Kirbie, C; Krawczyk, F L; Russell, S J; Wangler, T P

    2004-01-01

    Gamma-ray sources, particularly sources that are easily transportable, are in high demand for different homeland security applications. We have carried out a review of commercially available electron-linac-based sources, and have investigated alternative compact electron-linac systems that use updated technologies compared with sources that are available commercially. As the results, we propose to develop a new source using an electron linac operating at 17 GHz. It uses a klystron, instead of a magnetron, and a IGBT-switched HV power supply. The source design takes advantages of the advances in X-band linac technology and solid-state HV technology. The higher frequency and upgraded technologies offer smaller size, lighter weight, better efficiency, easier operation, and higher reliability, compared with commercially-available linacs. In this paper, we will describe the source design and our choice of technologies.

  13. A high-compression electron gun for C6+ production: concept, simulations and mechanical design

    Science.gov (United States)

    Mertzig, Robert; Breitenfeldt, M.; Mathot, S.; Pitters, J.; Shornikov, A.; Wenander, F.

    2017-07-01

    In this paper we report on simulations and the mechanical design of a high-compression electron gun for an Electron Beam Ion Source (EBIS) dedicated for production of high intensity and high repetition rate pulses of bare carbon ions for injection into linac-based hadron therapy facilities. The gun is presently under construction at CERN to be retrofitted into the TwinEBIS test bench for experimental studies. We describe the design constraints, show results of numeric simulations and report on the mechanical design featuring several novel ideas. The reported design makes use of combined-function units with reduced number of mechanical joints that were carefully controlled and tuned during the manufacturing phase. The simulations addressed a wide range of topics including the influence of thermal effects, focusing optics, symmetry-breaking misalignments and injection into a full 5 T field.

  14. TOF Spectroscopy measurement with waveform Digitizer at TMSR Photoneutron Source

    CERN Document Server

    Liu, Longxiang; Ma, Yugang; Cao, Xiguang; Cai, Xiangzhou; Chen, Jingen; Zhang, Guilin; Han, Jianlong; Zhang, Guogiang; Hu, Jifeng; Wang, Xiaohe

    2015-01-01

    The Photo-Neutron Source(PNS,phase 1), is an electron linear accelerator (linac) based pulsed neutron facility, combined with TOF technique, was constructed for nuclear data measurement of Thorium Molten Salt Reactor(TMSR) in Shanghai Institute of Applied Physics(SINAP) at JiaDing campus. The TOF detector signal, with the arrive time, pulse shape and pulse hight information, was recorded by a waveform digitizer. Through the pulse-shape discrimination(PSD) between neutrons and gamma-rays and time of Gamma Flash and Neutron signal analyse, the neutron TOF spectrum was deduced with this simple electronics design, and a new DAQ system based on waveform digitizer was used in this test experiment.

  15. High-gradient high-duty-factor Rf photo-cathode electron gun

    Science.gov (United States)

    Rimmer, R. A.; Hartman, N.; Lidia, S. M.; Wang, S.

    2002-05-01

    We describe the analysis and preliminary design of a high-gradient, high-duty factor RF photocathode gun. The gun is designed to operate at high repetition rate or CW, with high gradient on the cathode surface to minimize emittance growth due to space charge forces at high bunch charge. The gun may also be operated in a solenoidal magnetic field for emittance compensation. The design is intended for use in short-pulse, high-charge, and high-repetition rate applications such as linac based X-ray sources. We present and compare the results of gun simulations using different codes, as well as RF and thermal analysis of the structure.

  16. Pulsed Photofission Delayed Gamma Ray Detection for Nuclear Material Identification

    Energy Technology Data Exchange (ETDEWEB)

    John Kavouras; Xianfei Wen; Daren R. Norman; Dante R. Nakazawa; Haori Yang

    2012-11-01

    Innovative systems with increased sensitivity and resolution are in great demand to detect diversion and to prevent misuse in support of nuclear materials management for the U.S. fuel cycle. Nuclear fission is the most important multiplicative process involved in non-destructive active interrogation. This process produces the most easily recognizable signature for nuclear materials. High-energy gamma rays can also excite a nucleus and cause fission through a process known as photofission. After photofission reactions, delayed signals are easily distinguishable from the interrogating radiation. Linac-based, advanced inspection techniques utilizing the fission signals after photofission have been extensively studied for homeland security applications. Previous research also showed that a unique delayed gamma ray energy spectrum exists for each fissionable isotope. Isotopic composition measurement methods based on delayed gamma ray spectroscopy will be the primary focus of this work.

  17. Late bilateral temporal lobe necrosis after conventional radiotherapy. Case report

    Energy Technology Data Exchange (ETDEWEB)

    Hoshi, Michio; Hayashi, Toshiyuki; Kagami, Hiroshi; Murase, Ikurou; Nakatsukasa, Masashi [Saiseikai Utsunomiya Hospital (Japan)

    2003-04-01

    A 63-year-old woman presented with radionecrosis in the bilateral temporal lobes manifesting as dementia about 30 years after undergoing conventional radiotherapy for pituitary adenoma. Computed tomography and magnetic resonance (MR) imaging showed edema and cystic lesions in both temporal lobes. The mass in the left temporal lobe was excised. MR imaging 12 days after surgery showed reduced edema. Her dementia had improved. Radionecrosis usually occurs between several months and a few years after radiotherapy. The incidence of radionecrosis is estimated as 5%, but may be higher with longer follow-up periods. Clinical reports have suggested that larger total doses of radiation are associated with earlier onset of delayed necrosis and the fractional dose is the most significant factor causing cerebral radionecrosis. Radionecrosis can occur long after conventional radiotherapy or stereotactic radiosurgery using a linac-based system or a gamma knife unit. (author)

  18. Compact x-ray lasers in the laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Barletta, W.A.

    1988-10-03

    Compact x-ray lasers in the laboratory can be produced with ultrahigh gradient rf linacs based on recent advances in linac technology by an SLAC-LLNL-LBL collaboration and on the development of bright, high current electron sources by BNL and LANL. The GeV electron beams generated with such accelerators can be converted to soft x rays in the range of 2--10 nm by passage through short period, high field strength wigglers. Alternatively, the beam can pump a low density dielectric to produce x rays via recombination. Such linear light sources can produce trains of picosecond (or shorter) pulses of extremely high spectral brilliance suitable for flash holography of biological specimens in vivo and for studies of fast chemical reactions. 15 refs., 7 figs., 3 tabs.

  19. Linear accelerator radiosurgery for arteriovenous malformations: Updated literature review.

    Science.gov (United States)

    Yahya, S; Heyes, G; Nightingale, P; Lamin, S; Chavda, S; Geh, I; Spooner, D; Cruickshank, G; Sanghera, P

    2017-04-01

    Arteriovenous malformations (AVMs) are the leading causing of intra-cerebral haemorrhage. Stereotactic radiosurgery (SRS) is an established treatment for arteriovenous malformations (AVM) and commonly delivered using Gamma Knife within dedicated radiosurgery units. Linear accelerator (LINAC) SRS is increasingly available however debate remains over whether it offers an equivalent outcome. The aim of this project is to evaluate the outcomes using LINAC SRS for AVMs used within a UK neurosciences unit and review the literature to aid decision making across various SRS platforms. Results have shown comparability across platforms and strongly supports that an adapted LINAC based SRS facility within a dynamic regional neuro-oncology department delivers similar outcomes (in terms of obliteration and toxicity) to any other dedicated radio-surgical platform. Locally available facilities can facilitate discussion between options however throughput will inevitably be lower than centrally based dedicated national radiosurgery units.

  20. Steady-state thermal studies on the HIE-ISOLDE high-$\\beta$ superconducting cavities

    CERN Document Server

    Alberty, L

    2013-01-01

    The activity of the High Intensity and Energy ISOLDE (HIE-ISOLDE) project aims to construct a superconducting linac based on 101.28 MHz niobium sputtered Quarter Wave Resonators (QWRs). For this, several prototypes of superconducting cavities are currently being developed at CERN using OFE copper as substrate material for Niobium film coating. Two main concepts are currently under development: one consists of rolled, machined, deepdrawed and welded parts; the other is based on machined parts which are put together using electron beam welding. This study presents the results of simulations carried out in order to assess the thermal performance of different designs. The interest for such analysis was raised up before launching the manufacture of the first industrial series, since both rolled and bulk approaches seemed possible.

  1. Diagnostics and Instrumentation for FEL

    CERN Document Server

    Couprie, M E

    2001-01-01

    Free Electron Laser are coherent sources of radiation based on the interaction of a relativistic electron beam in an undulator field. According to the energy of the accelerator, they presently cover a wide spectral range, from the infra-red to the VUV. FELs combine the diagnostics of typical laser systems (for the measurement of spectral and temporal characteristics, the transverse mode pattern, the polarisation) and the diagnostics of relativistic electron beams. The electron beam is characterised in order to evaluate and control the FEL performances, but also in order to measure the effect of the FEL on the electron beam. The FEL characteristics are monitored with various types of detectors, depending mainly on the spectral range. Diagnostics for Linac based Infra Red FELs and storage ring FELs in the UV-VUV will be described. Particular instrumentation, required for FEL operation, such as the optical resonator, possible diagnostics inside the undulator will also be analysed.

  2. Liquid sample delivery techniques for serial femtosecond crystallography.

    Science.gov (United States)

    Weierstall, Uwe

    2014-07-17

    X-ray free-electron lasers overcome the problem of radiation damage in protein crystallography and allow structure determination from micro- and nanocrystals at room temperature. To ensure that consecutive X-ray pulses do not probe previously exposed crystals, the sample needs to be replaced with the X-ray repetition rate, which ranges from 120 Hz at warm linac-based free-electron lasers to 1 MHz at superconducting linacs. Liquid injectors are therefore an essential part of a serial femtosecond crystallography experiment at an X-ray free-electron laser. Here, we compare different techniques of injecting microcrystals in solution into the pulsed X-ray beam in vacuum. Sample waste due to mismatch of the liquid flow rate to the X-ray repetition rate can be addressed through various techniques.

  3. An injector for the proposed Berkeley Ultrafast X-Ray Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Lidia, Steven; Corlett, John; Pusina, Jan; Staples, John; Zholents, Alexander

    2003-05-19

    Berkeley Lab has proposed to build a recirculating linac based X-ray source for ultra-fast dynamic studies [1]. This machine requires a flat electron beam with a small vertical emittance and large x/y emittance ratio to allow for compression of spontaneous undulator emission of soft and hard x-ray pulses, and a low-emittance, round electron beam for coherent emission of soft x-rays via the FEL process based on cascaded harmonic generation [2]. We propose an injector system consisting of two high gradient high repetition rate photo cathode guns [3] (one for each application), an {approx}120 MeV super conducting linear accelerator, a 3rd harmonic cavity for linearization of the longitudinal phase space, and a bunch compressor. We present details of the design and the results of particle tracking studies using several computer codes.

  4. Quality of Intensity Modulated Radiation Therapy Treatment Plans Using a (60)Co Magnetic Resonance Image Guidance Radiation Therapy System

    DEFF Research Database (Denmark)

    Wooten, H Omar; Green, Olga; Yang, Min

    2015-01-01

    % prescription reference isodoses, respectively, and heterogeneity was on average 4% greater. Comparisons of OAR mean dose showed generally better sparing with linac plans in the low-dose range doses >20 Gy. The mean doses for all (60)Co plan OARs were within......PURPOSE: This work describes a commercial treatment planning system, its technical features, and its capabilities for creating (60)Co intensity modulated radiation therapy (IMRT) treatment plans for a magnetic resonance image guidance radiation therapy (MR-IGRT) system. METHODS AND MATERIALS...... plans using a third-party linear accelerator (linac)-based planning system were also created. Plans were evaluated by attending physicians and approved for treatment. The (60)Co and linac plans were compared by evaluating conformity numbers (CN) with 100% and 95% of prescription reference doses...

  5. MIXI: Mobile Intelligent X-Ray Inspection System

    Science.gov (United States)

    Arodzero, Anatoli; Boucher, Salime; Kutsaev, Sergey V.; Ziskin, Vitaliy

    2017-07-01

    A novel, low-dose Mobile Intelligent X-ray Inspection (MIXI) concept is being developed at RadiaBeam Technologies. The MIXI concept relies on a linac-based, adaptive, ramped energy source of short X-ray packets of pulses, a new type of fast X-ray detector, rapid processing of detector signals for intelligent control of the linac, and advanced radiography image processing. The key parameters for this system include: better than 3 mm line pair resolution; penetration greater than 320 mm of steel equivalent; scan speed with 100% image sampling rate of up to 15 km/h; and material discrimination over a range of thicknesses up to 200 mm of steel equivalent. Its minimal radiation dose, size and weight allow MIXI to be placed on a lightweight truck chassis.

  6. On the accuracy of localization achievable in fiducial-based stereoscopic image registration system using an electronic portal imaging device.

    Science.gov (United States)

    Ung, N M; Wee, L

    2012-06-01

    Portal imaging using electronic portal imaging device (EPID) is a well-established image-guided radiation therapy (IGRT) technique for external beam radiation therapy. The aims of this study are threefold; (i) to assess the accuracy of isocentre localization in the fiducial-based stereoscopic image registration, (ii) to investigate the impact of errors in the beam collimation device on stereoscopic registration, and (iii) to evaluate the intra- and inter-observer variability in stereoscopic registration. Portal images of a ball bearing phantom were acquired and stereoscopic image registrations were performed based on a point centred in the ball bearing as the surrogate for registration. Experiments were replicated by applying intentional offsets in the beam collimation device to simulate collimation errors. The accuracy of fiducial markers localization was performed by repeating the experiment using three spherical lead shots implanted in a pelvic phantom. Portal images of pelvis phantom were given to four expert users to assess the inter-observer variability in performing registration. The isocentre localization accuracy tested using ball bearing phantom was within 0.3 mm. Gravity-induced systematic errors of beam collimation device by 2 mm resulted in positioning offsets of the order of 2 mm opposing the simulated errors. Relatively large inter-portal pair projection errors ranges from 1.3 mm to 1.8 mm were observed with simulated errors in the beam collimation device. The intra-user and inter-user variabilities were observed to be 0.8 and 0.4 mm respectively. Fiducial-based stereoscopic image registration using EPID is robust for IGRT procedure.

  7. RAPIDARC (RA) in the uterine cervical cancer; dosimetric gain vs 3D-Crt; RAPIDARC (RA) en el cancer de cervix uterino; ganancia dosimetrica vs 3D-CRT

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, J.; Garcia, B.; Quispe, K.; Gonzales, A.; Marquina, J., E-mail: jose.ramirez@aliada.com.pe [Clinica Aliada, Oncologia Integral, Av. Jose Galvez Barrenechea 1044, San Isidro, Lima (Peru)

    2014-08-15

    This work aims to quantitatively assess RAPIDARC (RA) treatments versus three dimensional-Conformal Radiation Therapy with field to field technique (3D-Crt-Fin F). 11 patients with cervical cancer treated at our institution radically or adjuvant clinical stages I-III B were evaluated. The prescribed dose was 50 Gy (2 Gy / Fr). The RA plans consisted of two isocentric complete arcs and conformational plans of 4 isocentric fields (previous, subsequent, right side and left side) with 3D-Crt-Fin F technique; both cases carried out ??in the Eclipse version 10 planner with calculation algorithm analytical anisotropic algorithm (AAA) and volumetric optimization software (for VMAT plans). Homogeneity indices (Hi), conformity indices (CI) Sigma indices (S-Index), monitor units (MU) and the time required for each treatment were compared. The mean age was 52 years (32-65) of the 11 patients 9 were clinical stages I-II B. The Hi varied from 0.052 for RA to 0.163 for 3D-Crt-Fin F (p = 0.009), and the CI between 1.005 and 1.35 (p = 0.26), the S-index from 1.2 to 3.7 (p = 0.001) and the H-index of 1.08 to 1.15 (p = 0.24). All dose limits in risk organs were met with a significant difference in the RA plans versus 3D-Crt-Fin F. In patients with cervical cancer the treatment plans quality with the indices aforementioned seems to be better with the RA technique, being observed a significant reduction of radiation to surrounding organs. (author)

  8. Validation and clinical implementation of commercial secondary check software with heterogeneity corrections.

    Science.gov (United States)

    Kuppusamy, Vijayalakshmi; Nagarajan, Vivekanandan; Murugan, Lavanya

    2016-01-01

    To validate and implement PTW diamond secondary check software (SCS) in a routine clinical use. The secondary independent monitor unit or dose calculation verifications have led to a significant increase in the workflow associated with QA treatments. Modelling, validation and commissioning are necessary steps thereby making it a useful tool for QA. PTW Diamond SCS is capable of calculating VMAT fields, based on modified Clarkson integration, accounting for multi-leaf collimators (MLC) transmission and measured collimator scatter factors. Validation for heterogeneity corrections is made using circular phantom with inserts of various density materials. 150 VMAT plans were compared using (i) plans calculated in homogeneous cylindrical phantom and (ii) VMAT plans calculated with heterogeneity corrections using electron density values for each organ. Diamond SCS calculated dose for homogeneous cylindrical phantom resulted in average deviation of (0.1 ± 2.14%) with Eclipse TPS calculated dose and (-2.0 ± 1.66%) with absolute measured dose. PTW's OCTAVIUS-4D phantom with 729 ion chamber detector array measurements agreed well with Eclipse TPS calculated dose showing an average deviation of (-1.69 ± 1.56%). Diamond SCS dose calculations were performed with heterogeneity corrections for 124 VMAT plans with isocentre at a region above -350 HU. The overall MU variations between Diamond SCS and TPS Acuros-XB algorithms were within ±5%. Hence, the Diamond SCS can be used as an additional tool along with phantom measurements for patient specific quality assurance of VMAT plans with heterogeneity corrections having isocentre at a region above -350 HU.

  9. Pencil beam scanning dosimetry for large animal irradiation.

    Science.gov (United States)

    Lin, Liyong; Solberg, Timothy D; Carabe, Alexandro; Mcdonough, James E; Diffenderfer, Eric; Sanzari, Jenine K; Kennedy, Ann R; Cengel, Keith

    2014-09-01

    The space radiation environment imposes increased dangers of exposure to ionizing radiation, particularly during a solar particle event. These events consist primarily of low-energy protons that produce a highly inhomogeneous depth-dose distribution. Here we describe a novel technique that uses pencil beam scanning at extended source-to-surface distances and range shifter (RS) to provide robust but easily modifiable delivery of simulated solar particle event radiation to large animals. Thorough characterization of spot profiles as a function of energy, distance and RS position is critical to accurate treatment planning. At 105 MeV, the spot sigma is 234 mm at 4800 mm from the isocentre when the RS is installed at the nozzle. With the energy increased to 220 MeV, the spot sigma is 66 mm. At a distance of 1200 mm from the isocentre, the Gaussian sigma is 68 mm and 23 mm at 105 MeV and 220 MeV, respectively, when the RS is located on the nozzle. At lower energies, the spot sigma exhibits large differences as a function of distance and RS position. Scan areas of 1400 mm (superior-inferior) by 940 mm (anterior-posterior) and 580 mm by 320 mm are achieved at the extended distances of 4800 mm and 1200 mm, respectively, with dose inhomogeneity <2%. To treat large animals with a more sophisticated dose distribution, spot size can be reduced by placing the RS closer than 70 mm to the surface of the animals, producing spot sigmas below 6 mm.

  10. A modular approach to intensity-modulated arc therapy optimization with noncoplanar trajectories

    Science.gov (United States)

    Papp, Dávid; Bortfeld, Thomas; Unkelbach, Jan

    2015-07-01

    Utilizing noncoplanar beam angles in volumetric modulated arc therapy (VMAT) has the potential to combine the benefits of arc therapy, such as short treatment times, with the benefits of noncoplanar intensity modulated radiotherapy (IMRT) plans, such as improved organ sparing. Recently, vendors introduced treatment machines that allow for simultaneous couch and gantry motion during beam delivery to make noncoplanar VMAT treatments possible. Our aim is to provide a reliable optimization method for noncoplanar isocentric arc therapy plan optimization. The proposed solution is modular in the sense that it can incorporate different existing beam angle selection and coplanar arc therapy optimization methods. Treatment planning is performed in three steps. First, a number of promising noncoplanar beam directions are selected using an iterative beam selection heuristic; these beams serve as anchor points of the arc therapy trajectory. In the second step, continuous gantry/couch angle trajectories are optimized using a simple combinatorial optimization model to define a beam trajectory that efficiently visits each of the anchor points. Treatment time is controlled by limiting the time the beam needs to trace the prescribed trajectory. In the third and final step, an optimal arc therapy plan is found along the prescribed beam trajectory. In principle any existing arc therapy optimization method could be incorporated into this step; for this work we use a sliding window VMAT algorithm. The approach is demonstrated using two particularly challenging cases. The first one is a lung SBRT patient whose planning goals could not be satisfied with fewer than nine noncoplanar IMRT fields when the patient was treated in the clinic. The second one is a brain tumor patient, where the target volume overlaps with the optic nerves and the chiasm and it is directly adjacent to the brainstem. Both cases illustrate that the large number of angles utilized by isocentric noncoplanar VMAT plans

  11. DAVID--a translucent multi-wire transmission ionization chamber for in vivo verification of IMRT and conformal irradiation techniques.

    Science.gov (United States)

    Poppe, B; Thieke, C; Beyer, D; Kollhoff, R; Djouguela, A; Rühmann, A; Willborn, K C; Harder, D

    2006-03-07

    Permanent in vivo verification of IMRT photon beam profiles by a radiation detector with spatial resolution, positioned on the radiation entrance side of the patient, has not been clinically available so far. In this work we present the DAVID system, which is able to perform this quality assurance measurement while the patient is treated. The DAVID system is a flat, multi-wire transmission-type ionization chamber, placed in the accessory holder of the linear accelerator and constructed from translucent materials in order not to interfere with the light field. Each detection wire of the chamber is positioned exactly in the projection line of a MLC leaf pair, and the signal of each wire is proportional to the line integral of the ionization density along this wire. Thereby, each measurement channel essentially presents the line integral of the ionization density over the opening width of the associated leaf pair. The sum of all wire signals is a measure of the dose-area product of the transmitted photon beam and of the total radiant energy administered to the patient. After the dosimetric verification of an IMRT plan, the values measured by the DAVID system are stored as reference values. During daily treatment the signals are re-measured and compared to the reference values. A warning is output if there is a deviation beyond a threshold. The error detection capability is a leaf position error of less than 1 mm for an isocentric 1 cm x 1 cm field, and of 1 mm for an isocentric 20 cm x 20 cm field.

  12. SU-E-T-632: A Dosimetric Comparison of the 3D-CRT Planning of Chest Wall in Post-Mastectomy Breast Cancer Patients, with and Without Breast Board Setup

    Energy Technology Data Exchange (ETDEWEB)

    Muzaffar, Ambreen; Masood, Asif; Ullah, Haseeb; Mehmood, Kashif; Qasim, Uzma; Afridi, M. Ali; Khan, Salim; Hameed, Abdul [Radiation Oncology Department, Shifa International Hospitals Ltd. Sector H-8/4 Islamabad (Pakistan)

    2014-06-15

    Purpose: Breast boards are used in breast radiation which increases normal lung and heart doses, when supraclavicular field is included. Therefore, in this study through dose volume histogram (DVHs), lung and heart doses comparison was done between two different setups i.e. with and without breast board, for the treatment of left chest wall and supraclavicular fossa in postmastectomy left breast cancer. Methods: In this study, CT-Simulation scans of ten breast cancer patients were done with and without breast board, at Shifa International Hospitals Islamabad, to investigate the differences between the two different setups of the irradiation of left chest wall in terms of lung and heart doses. For immobilization, support under the neck, shoulders and arms was used. Precise PLAN 2.15 treatment planning system (TPS) was used for 3D-CRT planning. The total prescribed dose for both the plans was 5000 cGy/25 fractions. The chest wall was treated with a pair of tangential photon fields and the upper supraclavicular nodal regions were treated with an anterior photon field. A mono-isocentric technique was used to match the tangential fields with the anterior field at the isocentre. The dose volume histogram was used to compare the doses of heart and ipsilateral lung. Results: Both the plans of each patient were generated and compared. DVH results showed that for the same PTV dose coverage, plans without breast board resulted in a reduction of lung and heart doses compared with the plans with breast board. There was significant reductions in V20, V<25 and mean doses for lung and V<9 and mean doses for heart. Conclusion: In comparison of both the plans, setup without breast board significantly reduced the dose-volume of the ipsilateral lung and heart in left chest wall patients. Waived registration request has been submitted.

  13. Practical implications for the quality assurance of modulated radiation therapy techniques using point detector arrays.

    Science.gov (United States)

    Kantz, Steffi; Troeller McDermott, Almut; Söhn, Matthias; Reinhardt, Sabine; Belka, Claus; Parodi, Katia; Reiner, Michael

    2017-08-30

    Linac parameters potentially influencing the delivery quality of IMRT and VMAT plans are investigated with respect to threshold ranges, consequently to be considered in a linac based quality assurance procedure. Three commercially available 2D arrays are used to further investigate the influence of the measurement device. Using three commercially available 2D arrays (Mx: MatriXX(evolution) , Oc: Octavius(1500) , Mc: MapCHECK2), simple static measurements, measurements for MLC characterization and dynamic interplay of gantry movement, MLC movement and variable dose rate were performed. The results were evaluated with respect to each single array as well as among each other. Simple static measurements showed different array responses to dose, dose rate and profile homogeneity and revealed instabilities in dose delivery and profile shape during linac ramp up. Using the sweeping gap test, all arrays were able to detect small leaf misalignments down to ±0.1 mm, but this test also demonstrated up to 15% dose deviation due to profile instabilities and fast accelerating leaves during linac ramp up. Tests including gantry rotation showed different stability of gantry mounts for each array. Including gantry movement and dose rate variability, differences compared to static delivery were smaller compared to dose differences when simultaneously controling interplay of gantry movement, leaf movement and dose rate variability. Linac based QA is feasible with the tested commercially available 2D arrays. Limitations of each array and the linac ramp up characteristics should be carefully considered during individual plan generation and regularly checked in linac QA. Especially the dose and dose profile during linac ramp up should be checked regularly, as well as MLC positioning accuracy using a sweeping gap test. Additionally, dynamic interplay tests including various gantry rotation speeds and angles, various leaf speeds and various dose rates should be included. © 2017 The

  14. WE-B-19A-01: SRT II: Uncertainties in SRT

    Energy Technology Data Exchange (ETDEWEB)

    Dieterich, S [UC Davis Medical Center, Sacramento, CA (United States); Schlesinger, D [University of Virginia Health Systems, Charlottesville, VA (United States); Geneser, S [University of California San Francisco, San Francisco, CA (United States)

    2014-06-15

    SRS delivery has undergone major technical changes in the last decade, transitioning from predominantly frame-based treatment delivery to imageguided, frameless SRS. It is important for medical physicists working in SRS to understand the magnitude and sources of uncertainty involved in delivering SRS treatments for a multitude of technologies (Gamma Knife, CyberKnife, linac-based SRS and protons). Sources of SRS planning and delivery uncertainty include dose calculation, dose fusion, and intra- and inter-fraction motion. Dose calculations for small fields are particularly difficult because of the lack of electronic equilibrium and greater effect of inhomogeneities within and near the PTV. Going frameless introduces greater setup uncertainties that allows for potentially increased intra- and interfraction motion, The increased use of multiple imaging modalities to determine the tumor volume, necessitates (deformable) image and contour fusion, and the resulting uncertainties introduced in the image registration process further contribute to overall treatment planning uncertainties. Each of these uncertainties must be quantified and their impact on treatment delivery accuracy understood. If necessary, the uncertainties may then be accounted for during treatment planning either through techniques to make the uncertainty explicit, or by the appropriate addition of PTV margins. Further complicating matters, the statistics of 1-5 fraction SRS treatments differ from traditional margin recipes relying on Poisson statistics. In this session, we will discuss uncertainties introduced during each step of the SRS treatment planning and delivery process and present margin recipes to appropriately account for such uncertainties. Learning Objectives: To understand the major contributors to the total delivery uncertainty in SRS for Gamma Knife, CyberKnife, and linac-based SRS. Learn the various uncertainties introduced by image fusion, deformable image registration, and contouring

  15. Ultrafast X-ray Science at the Sub-Picosecond Pulse Source

    Energy Technology Data Exchange (ETDEWEB)

    Gaffney, Kelly J.; /SLAC, SSRL

    2005-09-30

    The ultrafast, high brightness x-ray free electron laser (XFEL) sources of the future have the potential to revolutionize the study of time dependent phenomena in the natural sciences. These linear accelerator (linac) sources will generate femtosecond (fs) x-ray pulses with peak flux comparable to conventional lasers, and far exceeding all other x-ray sources. The Stanford Linear Accelerator Center (SLAC) has pioneered the development of linac science and technology for decades, and since 2000 SLAC and the Stanford Synchrotron Radiation Laboratory (SSRL) have focused on the development of linac based ultrafast electron and x-ray sources. This development effort has led to the creation of a new x-ray source, called the Sub-Picosecond Pulse Source (SPPS), which became operational in 2003 [1]. The SPPS represents the first step toward the world's first hard x-ray free electron laser (XFEL), the Linac Coherent Light Source (LCLS), due to begin operation at SLAC in 2009. The SPPS relies on the same linac-based acceleration and electron bunch compression schemes that will be used at the LCLS to generate ultrashort, ultrahigh peak brightness electron bunches [2]. This involves creating an energy chirp on the electron bunch during acceleration and subsequent compression of the bunch in a series of energy-dispersive magnetic chicanes to create 80 fs electron pulses. The SPPS has provided an excellent opportunity to demonstrate the viability of these electron bunch compression schemes and to pursue goals relevant to the utilization and validation of XFEL light sources.

  16. Monolithic silicon photonics in a sub-100nm SOI CMOS microprocessor foundry: progress from devices to systems

    Science.gov (United States)

    Popović, Miloš A.; Wade, Mark T.; Orcutt, Jason S.; Shainline, Jeffrey M.; Sun, Chen; Georgas, Michael; Moss, Benjamin; Kumar, Rajesh; Alloatti, Luca; Pavanello, Fabio; Chen, Yu-Hsin; Nammari, Kareem; Notaros, Jelena; Atabaki, Amir; Leu, Jonathan; Stojanović, Vladimir; Ram, Rajeev J.

    2015-02-01

    We review recent progress of an effort led by the Stojanović (UC Berkeley), Ram (MIT) and Popović (CU Boulder) research groups to enable the design of photonic devices, and complete on-chip electro-optic systems and interfaces, directly in standard microelectronics CMOS processes in a microprocessor foundry, with no in-foundry process modifications. This approach allows tight and large-scale monolithic integration of silicon photonics with state-of-the-art (sub-100nm-node) microelectronics, here a 45nm SOI CMOS process. It enables natural scale-up to manufacturing, and rapid advances in device design due to process repeatability. The initial driver application was addressing the processor-to-memory communication energy bottleneck. Device results include 5Gbps modulators based on an interleaved junction that take advantage of the high resolution of the sub-100nm CMOS process. We demonstrate operation at 5fJ/bit with 1.5dB insertion loss and 8dB extinction ratio. We also demonstrate the first infrared detectors in a zero-change CMOS process, using absorption in transistor source/drain SiGe stressors. Subsystems described include the first monolithically integrated electronic-photonic transmitter on chip (modulator+driver) with 20-70fJ/bit wall plug energy/bit (2-3.5Gbps), to our knowledge the lowest transmitter energy demonstrated to date. We also demonstrate native-process infrared receivers at 220fJ/bit (5Gbps). These are encouraging signs for the prospects of monolithic electronics-photonics integration. Beyond processor-to-memory interconnects, our approach to photonics as a "More-than- Moore" technology inside advanced CMOS promises to enable VLSI electronic-photonic chip platforms tailored to a vast array of emerging applications, from optical and acoustic sensing, high-speed signal processing, RF and optical metrology and clocks, through to analog computation and quantum technology.

  17. Optical waveguiding and applied photonics technological aspects, experimental issue approaches and measurements

    CERN Document Server

    Massaro, Alessandro

    2012-01-01

    Optoelectronics--technology based on applications light such as micro/nano quantum electronics, photonic devices, laser for measurements and detection--has become an important field of research. Many applications and physical problems concerning optoelectronics are analyzed in Optical Waveguiding and Applied Photonics.The book is organized in order to explain how to implement innovative sensors starting from basic physical principles. Applications such as cavity resonance, filtering, tactile sensors, robotic sensor, oil spill detection, small antennas and experimental setups using lasers are a

  18. Polarization effects in the non-linear Compton scattering

    CERN Document Server

    Ivanov, D Y; Serbo, V G

    2005-01-01

    We consider emission of a photon by an electron in the field of a strong laser wave. A probability of this process for circularly or linearly polarized laser photons and for arbitrary polarization of all other particles is calculated. We obtain the complete set of functions which describe such a probability in a compact invariant form. Besides, we discuss in some detail the polarization effects in the kinematics relevant to the problem of electron to photon conversion at photon-photon and electron-photon colliders.

  19. Complete description of polarization effects in the nonlinear Compton scattering. I. Circularly polarized laser photons

    CERN Document Server

    Ivanov, D Y; Serbo, V G

    2003-01-01

    We consider emission of a photon by an electron in the field of a strong laser wave. Polarization effects in this process are important for a number of physical problems. We discuss a probability of this process for circularly polarized laser photons and for arbitrary polarization of all other particles. We obtain the complete set of functions which describe such a probability in a compact covariant form. Besides, we discuss an application of the obtained formulas to the problem of electron -> photon conversion at photon-photon and photon-electron colliders.

  20. Experimental Search for a Heavy Electron

    Science.gov (United States)

    Boley, C. D.; Elias, J. E.; Friedman, J. I.; Hartmann, G. C.; Kendall, H. W.; Kirk, P.N.; Sogard, M. R.; Van Speybroeck, L. P.; de Pagter, J. K.

    1967-09-01

    A search for a heavy electron of the type considered by Low and Blackmon has been made by studying the inelastic scattering of 5 BeV electrons from hydrogen. The search was made over a range of values of the mass of the heavy electron from 100 t0 1300 MeV. No evidence for such a particle was observed. Upper limits on the production cross sections were determined and employed to deducelimits on the values of the electron-photon-heavy electron coupling constant in Low and Blackmon=s theory.

  1. Production and decay of heavy selectrons; Produktion und Nachweis schwerer Selektronen

    Energy Technology Data Exchange (ETDEWEB)

    Csallner, S.

    2007-04-03

    We investigate the production and the decay of selectrons with masses beyond the threshold for pair production at future linear colliders with center-of-mass energies of 500 GeV and 800 GeV. For this we study the production of left and right selectrons in association with the lightest neutralino or chargino, respectively, via electron-electron, electron-positron and electron-photon scattering in the framework of the MSSM. Furthermore we analyse the production via electron-electron scattering in two extended models, the NMSSM and an E6-model with an additional U(1) gauge factor. (orig.)

  2. Nanowire formation is preceded by nanotube growth in templated electrodeposition of cobalt hybrid nanostructures

    Science.gov (United States)

    Dryden, Daniel M.; Vidu, Ruxandra; Stroeve, Pieter

    2016-11-01

    Cobalt fluted nanowires, novel nanostructures with a diameter of 200 nm consisting of a solid nanowire base and a thin, nanotubular flute shape, were grown in track-etched polycarbonate membranes via templated electrodeposition. The structures were characterized electrochemically via cyclic voltammetry, chronoamperometry, and charge stripping, and structurally via scanning electron microscopy, transmission electron microscopy, and focused ion beam cross-sectioning. Electrochemical and structural analysis reveals details of their deposition kinetics, structure, and morphology, and indicate possible mechanisms for their formation and control. These unique structures provide inspiration for an array of possible applications in electronics, photonics, and other fields.

  3. Secondary Emission Calorimetry: Fast and Radiation-Hard

    CERN Document Server

    Albayrak-Yetkin, A; Corso, J; Debbins, P; Jennings, G; Khristenko, V; Mestvirisvilli, A; Onel, Y; Schmidt, I; Sanzeni, C; Southwick, D; Winn, D R; Yetkin, T

    2013-01-01

    A novel calorimeter sensor for electron, photon and hadron energy measurement based on Secondary Emission(SE) to measure ionization is described, using sheet-dynodes directly as the active detection medium; the shower particles in an SE calorimeter cause direct secondary emission from dynode arrays comprising the sampling or absorbing medium. Data is presented on prototype tests and Monte Carlo simulations. This sensor can be made radiation hard at GigaRad levels, is easily transversely segmentable at the mm scale, and in a calorimeter has energy signal rise-times and integration comparable to or better than plastic scintillation/PMT calorimeters. Applications are mainly in the energy and intensity frontiers.

  4. Electronic Structure of Single-Crystal Monolayer Graphene on Hydrogen-Terminated Germanium Surface

    Science.gov (United States)

    Ahn, Sung Joon; Lee, Jae-Hyun; Ahn, Joung Real; Whang, Dongmok

    2015-03-01

    Graphene, atomically flat 2-Dimensional layered nano material, has a lot of interesting characteristics from its unusual electronic structure. Almost properties of graphene are influenced by its crystallinity, therefore the uniform growth of single crystal graphene and layer control over the wafer scale areas remains a challenge in the fields of electronic, photonic and other devices based on graphene. Here, we report the method to make wafer scale single crystal monolayer graphene on hydrogen terminated germanium(110) surface and properties and electronic band structure of the graphene by using the tool of scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, electron transport measurement, electron diffraction and angle-resolved photoemission spectroscopy.

  5. Vector polarimetry at MAMI

    Energy Technology Data Exchange (ETDEWEB)

    Nillius, Fabian; Aulenbacher, Kurt [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany)

    2013-07-01

    Electron/photon tensor-correlation coefficients may allow to design a polarimeter that can measure all components of beam polarisation simultaneously (''vector polarimeter''). Besides its purpose as a beam diagnostic device this would also allow to test theoretical predictions for the correlation coefficients at energies between 1 and 3.5 MeV. As a first step we have set up a measurement of the helicity transfer to the photon as a function of energy which is based on the Compton absorption method. Apparative developments in order to measure photon emission asymmetries caused by transverse and longitudinal electron polarisation are presented.

  6. Strongly Enhanced Effects of Lorentz-Symmetry Violation in Yb$^+$ and Highly Charged Ions

    CERN Document Server

    Safronova, M S

    2016-01-01

    A Lorentz-symmetry test with Ca$^+$ ions demonstrated the potential of using quantum information inspired technology for tests of fundamental physics. A systematic study of atomic-system sensitivities to Lorentz violation identified the ytterbium ion as an ideal system with high sensitivity as well as excellent experimental controllability. A test of Lorentz-violating physics in the electron-photon sector with Yb$^+$ ions has the potential to reach levels of 10$^{-23}$, five orders of magnitude more sensitive than the current best bounds. Similar sensitivities may be also reached with highly charged ions.

  7. Piezoelectric ZnO nanostructure for energy harvesting

    CERN Document Server

    Leprince-Wang, Yamin

    2015-01-01

    Over the past decade, ZnO as an important II-VI semiconductor has attracted much attention within the scientific community over the world owing to its numerous unique and prosperous properties. This material, considered as a "future material", especially in nanostructural format, has aroused many interesting research works due to its large range of applications in electronics, photonics, acoustics, energy and sensing. The bio-compatibility, piezoelectricity & low cost fabrication make ZnO nanostructure a very promising material for energy harvesting.

  8. Lepton and photon performance at ATLAS and CMS

    CERN Document Server

    Lesage, Arthur; The ATLAS collaboration

    2017-01-01

    These proceedings report on lepton and photon performance results obtained using data recorded in 2015 and 2016 at the LHC by the two experiments ATLAS and CMS. For each particle (electrons, photons and muons), the reconstruction and identification efficiencies are presented for the two experiments together with the isolation studies. Results concerning the electron and photon energy calibration as well as the muon momentum scale and resolution are also reported. Despite more challenging pile-up conditions with respect to Run 1, the two experiments achieved impressive performance in early Run 2.

  9. EGS code system: computer programs for the Monte Carlo simulation of electromagnetic cascade showers. Version 3. [EGS, PEGS, TESTSR, in MORTRAN

    Energy Technology Data Exchange (ETDEWEB)

    Ford, R.L.; Nelson, W.R.

    1978-06-01

    A code to simulate almost any electron--photon transport problem conceivable is described. The report begins with a lengthy historical introduction and a description of the shower generation process. Then the detailed physics of the shower processes and the methods used to simulate them are presented. Ideas of sampling theory, transport techniques, particle interactions in general, and programing details are discussed. Next, EGS calculations and various experiments and other Monte Carlo results are compared. The remainder of the report consists of user manuals for EGS, PEGS, and TESTSR codes; options, input specifications, and typical output are included. 38 figures, 12 tables. (RWR)

  10. Phase-I Trigger Readout Electronics Upgrade for the ATLAS Liquid-Argon Calorimeters

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00452211; The ATLAS collaboration

    2017-01-01

    The upgrade of the Large Hadron Collider (LHC) scheduled for the Long Shut-down period of 2019-2020 (LS2), referred to as Phase-I upgrade, will increase the instantaneous luminosity to about three times the design value. Since the current ATLAS trigger system does not allow sucient increase of the trigger rate, an improvement of the trigger system is required. The Liquid Argon (LAr) Calorimeter read-out will therefore be modi ed to use digital trigger signals with a higher spatial granularity in order to improve the identi cation effciencies of electrons, photons, tau, jets and missing energy, at high background rejection rates at the Level-1 trigger.

  11. Application of the Feynman-tree theorem together with BCFW recursion relations

    CERN Document Server

    Maniatis, Markos

    2016-01-01

    Recently, it has been shown that on-shell scattering amplitudes can be constructed by the Feynman-tree theorem combined with the BCFW recursion relations. Since the BCFW relations are restricted to tree diagrams, the preceding application of the Feynman-tree theorem is essential. In this way amplitudes can be constructed by on-shell and gauge-invariant tree amplitudes. Here we want to apply this method to the electron-photon vertex correction. We present all the single, double, and triple phase-space tensor integrals explicitly and show that the sum of amplitudes coincides with the result of the conventional calculation of a virtual loop correction.

  12. Experiment Pamir-3. Coplanar emission of high energy gamma-quanta at interaction of hadrons with nuclei of air atoms at energies above 10 to the 7th power GeV

    Science.gov (United States)

    Asatiani, T. L.; Genina, L. E.; Zatsepin, G. T.

    1985-01-01

    A systematic analysis of large gamma families, detected in X-ray emulsion chambers, cases of multicore halos have been observed, and among them five events in which the halo is divided into three of four separate cores with their alignment observed in the target diagram (coplanarity of axes of corresponding electron photon cascades). The halo alignment (tendency to the straight line) leads to the aximuthal asymmetry (thrust). The analysis of lateral and momentum distributions of particles in these families shows that they also have thrust that correlates with the direction of the halo core alignment.

  13. Thermophysics of condensed media. Teplofizika kondensirovannykh sred

    Energy Technology Data Exchange (ETDEWEB)

    Novikov, I.I.

    1985-01-01

    The papers presented in this volume deal with the properties of the condensed state of crystalline and amorphous solids and liquids. Topics discussed include a thermodynamic analysis of dissipative inhomogeneities in a continuum; the effect of plastic deformation of the electrical resistance of niobium; a study of the fine crystal structure, spinodal decomposition mechanism, and phase transformations in alloys based on Fe-Cr and Mu-Cu; and the optimal temperature of superplasticity. Papers are also included on the electron-photon interaction in Ti-V-Mo alloys, elastic properties and the nonlinear parameter of porous media, and hydrogen kinetics in a nickel-base amorphous alloy.

  14. Experimental aspects of QCD studies at the LHC

    CERN Document Server

    Tapprogge, Stefan

    2000-01-01

    The LHC will allow precision tests and measurements of QCD in as yet unexplored kinematic regions. The detailed understanding of QCD is important for almost all physics processes to be studied at LHC, as the production mechanisms are mostly controlled by QCD. The multi-purpose detectors (ATLAS and CMS) have been optimized for precision measurements within pseudorapidities of $|\\eta|<2.5$ and have calorimetric coverage up to $|\\eta|=5$. The expected performance will allow precise studies of final states containing electrons, photons, tau's (single hadrons), muons and jets. This contribution discusses various measurements of QCD processes at LHC, the kinematical reach and the expected statistical uncertainties for selected examples.

  15. The Nelson Model with Less Than Two Photons

    CERN Document Server

    Galtbayar, A; Yajima, K

    2002-01-01

    We study the spectral and scattering theory of the Nelson model for an atom interacting with a photon field in the subspace with less than two photons. For the free electron-photon system, the spectral property of the reduced Hamiltonian in the center of mass coordinates and the large time dynamics are determined. If the electron is under the influence of the nucleus via spatially decaying potentials, we locate the essential spectrum, prove the absence of singular continuous spectrum and the existence of the ground state, and construct wave operators giving the asymptotic dynamics.

  16. Performance of the CMS Level-1 Trigger during Commissioning with Cosmic Ray Muons and LHC beams

    CERN Document Server

    INSPIRE-00165402; Khachatryan, V; Sirunyan, A M; Adam, W; Arnold, B; Bergauer, H; Bergauer, T; Dragicevic, M; Eichberger, M; Erö, J; Friedl, M; Frühwirth, R; Ghete, V M; Hammer, J; Hänsel, S; Hoch, M; Hörmann, N; Hrubec, J; Jeitler, M; Kasieczka, G; Kastner, K; Krammer, M; Liko, D; Magrans de Abril, I; Mikulec, I; Mittermayr, F; Neuherz, B; Oberegger, M; Padrta, M; Pernicka, M; Rohringer, H; Schmid, S; Schöfbeck, R; Schreiner, T; Stark, R; Steininger, H; Strauss, J; Taurok, A; Teischinger, F; Themel, T; Uhl, D; Wagner, P; Waltenberger, W; Walzel, G; Widl, E; Wulz, C E; Chekhovsky, V; Dvornikov, O; Emeliantchik, I; Litomin, A; Makarenko, V; Marfin, I; Mossolov, V; Shumeiko, N; Solin, A; Stefanovitch, R; Suarez Gonzalez, J; Tikhonov, A; Fedorov, A; Karneyeu, A; Korzhik, M; Panov, V; Zuyeuski, R; Kuchinsky, P; Beaumont, W; Benucci, L; Cardaci, M; De Wolf, E A; Delmeire, E; Druzhkin, D; Hashemi, M; Janssen, X; Maes, T; Mucibello, L; Ochesanu, S; Rougny, R; Selvaggi, M; Van Haevermaet, H; Van Mechelen, P; Van Remortel, N; Adler, V; Beauceron, S; Blyweert, S; D'Hondt, J; De Weirdt, S; Devroede, O; Heyninck, J; Kalogeropoulos, A; Maes, J; Maes, M; Mozer, M U; Tavernier, S; Van Doninck, W; Van Mulders, P; Villella, I; Bouhali, O; Chabert, E C; Charaf, O; Clerbaux, B; De Lentdecker, G; Dero, V; Elgammal, S; Gay, A P R; Hammad, G H; Marage, P E; Rugovac, S; Vander Velde, C; Vanlaer, P; Wickens, J; Grunewald, M; Klein, B; Marinov, A; Ryckbosch, D; Thyssen, F; Tytgat, M; Vanelderen, L; Verwilligen, P; Basegmez, S; Bruno, G; Caudron, J; Delaere, C; Demin, P; Favart, D; Giammanco, A; Grégoire, G; Lemaitre, V; Militaru, O; Ovyn, S; Piotrzkowski, K; Quertenmont, L; Schul, N; Beliy, N; Daubie, E; Alves, G A; Pol, M E; Souza, M H G; Carvalho, W; De Jesus Damiao, D; De Oliveira Martins, C; Fonseca De Souza, S; Mundim, L; Oguri, V; Santoro, A; Silva Do Amaral, S M; Sznajder, A; Fernandez Perez Tomei, T R; Ferreira Dias, M A; Gregores, E M; Novaes, S F; Abadjiev, K; Anguelov, T; Damgov, J; Darmenov, N; Dimitrov, L; Genchev, V; Iaydjiev, P; Piperov, S; Stoykova, S; Sultanov, G; Trayanov, R; Vankov, I; Dimitrov, A; Dyulendarova, M; Kozhuharov, V; Litov, L; Marinova, E; Mateev, M; Pavlov, B; Petkov, P; Toteva, Z; Chen, G M; Chen, H S; Guan, W; Jiang, C H; Liang, D; Liu, B; Meng, X; Tao, J; Wang, J; Wang, Z; Xue, Z; Zhang, Z; Ban, Y; Cai, J; Ge, Y; Guo, S; Hu, Z; Mao, Y; Qian, S J; Teng, H; Zhu, B; Avila, C; Baquero Ruiz, M; Carrillo Montoya, C A; Gomez, A; Gomez Moreno, B; Ocampo Rios, A A; Osorio Oliveros, A F; Reyes Romero, D; Sanabria, J C; Godinovic, N; Lelas, K; Plestina, R; Polic, D; Puljak, I; Antunovic, Z; Dzelalija, M; Brigljevic, V; Duric, S; Kadija, K; Morovic, S; Fereos, R; Galanti, M; Mousa, J; Papadakis, A; Ptochos, F; Razis, P A; Tsiakkouri, D; Zinonos, Z; Hektor, A; Kadastik, M; Kannike, K; Müntel, M; Raidal, M; Rebane, L; Anttila, E; Czellar, S; Härkönen, J; Heikkinen, A; Karimäki, V; Kinnunen, R; Klem, J; Kortelainen, M J; Lampén, T; Lassila-Perini, K; Lehti, S; Lindén, T; Luukka, P; Mäenpää, T; Nysten, J; Tuominen, E; Tuominiemi, J; Ungaro, D; Wendland, L; Banzuzi, K; Korpela, A; Tuuva, T; Nedelec, P; Sillou, D; Besancon, M; Chipaux, R; Dejardin, M; Denegri, D; Descamps, J; Fabbro, B; Faure, J L; Ferri, F; Ganjour, S; Gentit, F X; Givernaud, A; Gras, P; Hamel de Monchenault, G; Jarry, P; Lemaire, M C; Locci, E; Malcles, J; Marionneau, M; Millischer, L; Rander, J; Rosowsky, A; Rousseau, D; Titov, M; Verrecchia, P; Baffioni, S; Bianchini, L; Bluj, M; Busson, P; Charlot, C; Dobrzynski, L; Granier de Cassagnac, R; Haguenauer, M; Miné, P; Paganini, P; Sirois, Y; Thiebaux, C; Zabi, A; Agram, J L; Besson, A; Bloch, D; Bodin, D; Brom, J M; Conte, E; Drouhin, F; Fontaine, J C; Gelé, D; Goerlach, U; Gross, L; Juillot, P; Le Bihan, A C; Patois, Y; Speck, J; Van Hove, P; Baty, C; Bedjidian, M; Blaha, J; Boudoul, G; Brun, H; Chanon, N; Chierici, R; Contardo, D; Depasse, P; Dupasquier, T; El Mamouni, H; Fassi, F; Fay, J; Gascon, S; Ille, B; Kurca, T; Le Grand, T; Lethuillier, M; Lumb, N; Mirabito, L; Perries, S; Vander Donckt, M; Verdier, P; Djaoshvili, N; Roinishvili, N; Roinishvili, V; Amaglobeli, N; Adolphi, R; Anagnostou, G; Brauer, R; Braunschweig, W; Edelhoff, M; Esser, H; Feld, L; Karpinski, W; Khomich, A; Klein, K; Mohr, N; Ostaptchouk, A; Pandoulas, D; Pierschel, G; Raupach, F; Schael, S; Schultz von Dratzig, A; Schwering, G; Sprenger, D; Thomas, M; Weber, M; Wittmer, B; Wlochal, M; Actis, O; Altenhöfer, G; Bender, W; Biallass, P; Erdmann, M; Fetchenhauer, G; Frangenheim, J; Hebbeker, T; Hilgers, G; Hinzmann, A; Hoepfner, K; Hof, C; Kirsch, M; Klimkovich, T; Kreuzer, P; Lanske, D; Merschmeyer, M; Meyer, A; Philipps, B; Pieta, H; Reithler, H; Schmitz, S A; Sonnenschein, L; Sowa, M; Steggemann, J; Szczesny, H; Teyssier, D; Zeidler, C; Bontenackels, M; Davids, M; Duda, M; Flügge, G; Geenen, H; Giffels, M; Haj Ahmad, W; Hermanns, T; Heydhausen, D; Kalinin, S; Kress, T; Linn, A; Nowack, A; Perchalla, L; Poettgens, M; Pooth, O; Sauerland, P; 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    2010-01-01

    The CMS Level-1 trigger was used to select cosmic ray muons and LHC beam events during data-taking runs in 2008, and to estimate the level of detector noise. This paper describes the trigger components used, the algorithms that were executed, and the trigger synchronisation. Using data from extended cosmic ray runs, the muon, electron/photon, and jet triggers have been validated, and their performance evaluated. Efficiencies were found to be high, resolutions were found to be good, and rates as expected.

  17. Single photon delayed feedback: a way to stabilize intrinsic quantum cavity electrodynamics.

    Science.gov (United States)

    Carmele, Alexander; Kabuss, Julia; Schulze, Franz; Reitzenstein, Stephan; Knorr, Andreas

    2013-01-01

    We propose a scheme to control cavity quantum electrodynamics in the single photon limit by delayed feedback. In our approach a single emitter-cavity system, operating in the weak coupling limit, can be driven into the strong coupling-type regime by an external mirror: The external loop produces Rabi oscillations directly connected to the electron-photon coupling strength. As an expansion of typical cavity quantum electrodynamics, we treat the quantum correlation of external and internal light modes dynamically and demonstrate a possible way to implement a fully quantum mechanical time-delayed feedback. Our theoretical approach proposes a way to experimentally feedback control quantum correlations in the single photon limit.

  18. Ultrafast and nanoscale diodes

    Science.gov (United States)

    Zhang, Peng; Lau, Y. Y.

    2016-10-01

    Charge carrier transport across interfaces of dissimilar materials (including vacuum) is the essence of all electronic devices. Ultrafast charge transport across a nanometre length scale is of fundamental importance in the miniaturization of vacuum and plasma electronics. With the combination of recent advances in electronics, photonics and nanotechnology, these miniature devices may integrate with solid-state platforms, achieving superior performance. This paper reviews recent modelling efforts on quantum tunnelling, ultrafast electron emission and transport, and electrical contact resistance. Unsolved problems and challenges in these areas are addressed.

  19. Spectrum: an educational computer game

    Science.gov (United States)

    Lee, John; Trigueros, María; Tagüeña, Julia; Barrio, Rafael A.

    1993-07-01

    The absorption and emission spectra of the hydrogen atom are explained through a computer game. The idea of electronic energy levels (quantization) is introduced by using the idea of the `right photon' to excite an electron. The software includes many important concepts such as mean lifetime, electrons, photons, spectra, ionization, etc. Deeper information is also available. The game is being tested and can be played in Universum, the Science Museum of the Universidad Nacional Autónoma de México.

  20. Out of Sight, Out of Mind—On Guy Schofield’s “Sleepers”

    Directory of Open Access Journals (Sweden)

    Jamie Allen

    2011-03-01

    Full Text Available Video. Computational “3D models” don’t actually model any thing. They are assumed imitative, but in contemporary production, these are vectorized thought- objects, prototypes of notions and design ideals. The photographic image on the other hand, as a pipeline of indexical pixels, is the apogee of our attempts to describe and represent the world outside. 65,536 levels of red, green and blue, rendered into and out of the real world of electrons, photons and “live-action.”

  1. Quantum Information Processing and Quantum Error Correction An Engineering Approach

    CERN Document Server

    Djordjevic, Ivan

    2012-01-01

    Quantum Information Processing and Quantum Error Correction is a self-contained, tutorial-based introduction to quantum information, quantum computation, and quantum error-correction. Assuming no knowledge of quantum mechanics and written at an intuitive level suitable for the engineer, the book gives all the essential principles needed to design and implement quantum electronic and photonic circuits. Numerous examples from a wide area of application are given to show how the principles can be implemented in practice. This book is ideal for the electronics, photonics and computer engineer

  2. Performance of the CMS Level-1 Trigger during Commissioning with Cosmic Ray Muons and LHC beams

    CERN Document Server

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Yarba, J; Yumiceva, F; Yun, J C; Acosta, D; Avery, P; Barashko, V; Bourilkov, D; Chen, M; Di Giovanni, G P; Dobur, D; Drozdetskiy, A; Field, R D; Fu, Y; Furic, I K; Gartner, J; Holmes, D; Kim, B; Klimenko, S; Konigsberg, J; Korytov, A; Kotov, K; Kropivnitskaya, A; Kypreos, T; Madorsky, A; Matchev, K; Mitselmakher, G; Pakhotin, Y; Piedra Gomez, J; Prescott, C; Rapsevicius, V; Remington, R; Schmitt, M; Scurlock, B; Wang, D; Yelton, J; Ceron, C; Gaultney, V; Kramer, L; Lebolo, L M; Linn, S; Markowitz, P; Martinez, G; Rodriguez, J L; Adams, T; Askew, A; Baer, H; Bertoldi, M; Chen, J; Dharmaratna, W G D; Gleyzer, S V; Haas, J; Hagopian, S; Hagopian, V; Jenkins, M; Johnson, K F; Prettner, E; Prosper, H; Sekmen, S; Baarmand, M M; Guragain, S; Hohlmann, M; Kalakhety, H; Mermerkaya, H; Ralich, R; Vodopiyanov, I; Abelev, B; Adams, M R; Anghel, I M; Apanasevich, L; Bazterra, V E; Betts, R R; Callner, J; Castro, M A; Cavanaugh, R; Dragoiu, C; Garcia-Solis, E J; Gerber, C E; Hofman, D J; Khalatian, S; Mironov, C; Shabalina, E; Smoron, A; Varelas, N; Akgun, U; Albayrak, E A; Ayan, A S; Bilki, B; Briggs, R; Cankocak, K; Chung, K; Clarida, W; Debbins, P; Duru, F; Ingram, F D; Lae, C K; McCliment, E; Merlo, J P; Mestvirishvili, A; Miller, M J; Moeller, A; Nachtman, J; Newsom, C R; Norbeck, E; Olson, J; Onel, Y; Ozok, F; Parsons, J; Schmidt, I; Sen, S; Wetzel, J; Yetkin, T; Yi, K; Barnett, B A; Blumenfeld, B; Bonato, A; Chien, C Y; Fehling, D; Giurgiu, G; Gritsan, A V; Guo, Z J; Maksimovic, P; Rappoccio, S; Swartz, M; Tran, N V; Zhang, Y; Baringer, P; Bean, A; Grachov, O; Murray, M; Radicci, V; Sanders, S; Wood, J S; Zhukova, V; Bandurin, D; Bolton, T; Kaadze, K; Liu, A; Maravin, Y; Onoprienko, D; Svintradze, I; Wan, Z; Gronberg, J; Hollar, J; Lange, D; Wright, D; Baden, D; Bard, R; Boutemeur, M; Eno, S C; Ferencek, D; Hadley, N J; Kellogg, R G; Kirn, M; Kunori, S; Rossato, K; Rumerio, P; Santanastasio, F; Skuja, A; Temple, J; Tonjes, M B; Tonwar, S C; Toole, T; Twedt, E; Alver, B; Bauer, G; Bendavid, J; Busza, W; Butz, E; Cali, I A; Chan, M; D'Enterria, D; Everaerts, P; Gomez Ceballos, G; Hahn, K A; Harris, P; Jaditz, S; Kim, Y; Klute, M; Lee, Y J; Li, W; Loizides, C; Ma, T; Miller, M; Nahn, S; Paus, C; Roland, C; Roland, G; Rudolph, M; Stephans, G; Sumorok, K; Sung, K; Vaurynovich, S; Wenger, E A; Wyslouch, B; Xie, S; Yilmaz, Y; Yoon, A S; Bailleux, D; Cooper, S I; Cushman, P; Dahmes, B; De Benedetti, A; Dolgopolov, A; Dudero, P R; Egeland, R; Franzoni, G; Haupt, J; Inyakin, A; Klapoetke, K; Kubota, Y; Mans, J; Mirman, N; Petyt, D; Rekovic, V; Rusack, R; Schroeder, M; Singovsky, A; Zhang, J; Cremaldi, L M; Godang, R; Kroeger, R; Perera, L; Rahmat, R; Sanders, D A; Sonnek, P; Summers, D; Bloom, K; Bockelman, B; Bose, S; Butt, J; Claes, D R; Dominguez, A; Eads, M; Keller, J; Kelly, T; Kravchenko, I; Lazo-Flores, J; Lundstedt, C; Malbouisson, H; Malik, S; Snow, G R; Baur, U; Iashvili, I; Kharchilava, A; Kumar, A; Smith, K; Strang, M; Alverson, G; Barberis, E; Boeriu, O; Eulisse, G; Govi, G; McCauley, T; Musienko, Y; Muzaffar, S; Osborne, I; Paul, T; Reucroft, S; Swain, J; Taylor, L; Tuura, L; Anastassov, A; Gobbi, B; Kubik, A; Ofierzynski, R A; Pozdnyakov, A; Schmitt, M; Stoynev, S; Velasco, M; Won, S; Antonelli, L; Berry, D; Hildreth, M; Jessop, C; Karmgard, D J; Kolberg, T; Lannon, K; Lynch, S; Marinelli, N; Morse, D M; Ruchti, R; Slaunwhite, J; Warchol, J; Wayne, M; Bylsma, B; Durkin, L S; Gilmore, J; Gu, J; Killewald, P; Ling, T Y; Williams, G; Adam, N; Berry, E; Elmer, P; Garmash, A; Gerbaudo, D; Halyo, V; Hunt, A; Jones, J; Laird, E; Marlow, D; Medvedeva, T; Mooney, M; Olsen, J; Piroué, P; Stickland, D; Tully, C; Werner, J S; Wildish, T; Xie, Z; Zuranski, A; Acosta, J G; Bonnett Del Alamo, M; Huang, X T; Lopez, A; Mendez, H; Oliveros, S; Ramirez Vargas, J E; Santacruz, N; Zatzerklyany, A; Alagoz, E; Antillon, E; Barnes, V E; Bolla, G; Bortoletto, D; Everett, A; Garfinkel, A F; Gecse, Z; Gutay, L; Ippolito, N; Jones, M; Koybasi, O; Laasanen, A T; Leonardo, N; Liu, C; Maroussov, V; Merkel, P; Miller, D H; Neumeister, N; Sedov, A; Shipsey, I; Yoo, H D; Zheng, Y; Jindal, P; Parashar, N; Cuplov, V; Ecklund, K M; Geurts, F J M; Liu, J H; Maronde, D; Matveev, M; Padley, B P; Redjimi, R; Roberts, J; Sabbatini, L; Tumanov, A; Betchart, B; Bodek, A; Budd, H; Chung, Y S; de Barbaro, P; Demina, R; Flacher, H; Gotra, Y; Harel, A; Korjenevski, S; Miner, D C; Orbaker, D; Petrillo, G; Vishnevskiy, D; Zielinski, M; Bhatti, A; Demortier, L; Goulianos, K; Hatakeyama, K; Lungu, G; Mesropian, C; Yan, M; Atramentov, O; Bartz, E; Gershtein, Y; Halkiadakis, E; Hits, D; Lath, A; Rose, K; Schnetzer, S; Somalwar, S; Stone, R; Thomas, S; Watts, T L; Cerizza, G; Hollingsworth, M; Spanier, S; Yang, Z C; York, A; Asaadi, J; Aurisano, A; Eusebi, R; Golyash, A; Gurrola, A; Kamon, T; Nguyen, C N; Pivarski, J; Safonov, A; Sengupta, S; Toback, D; Weinberger, M; Akchurin, N; Berntzon, L; Gumus, K; Jeong, C; Kim, H; Lee, S W; Popescu, S; Roh, Y; Sill, A; Volobouev, I; Washington, E; Wigmans, R; Yazgan, E; Engh, D; Florez, C; Johns, W; Pathak, S; Sheldon, P; Andelin, D; Arenton, M W; Balazs, M; Boutle, S; Buehler, M; Conetti, S; Cox, B; Hirosky, R; Ledovskoy, A; Neu, C; Phillips II, D; Ronquest, M; Yohay, R; Gollapinni, S; Gunthoti, K; Harr, R; Karchin, P E; Mattson, M; Sakharov, A; Anderson, M; Bachtis, M; Bellinger, J N; Carlsmith, D; Crotty, I; Dasu, S; Dutta, S; Efron, J; Feyzi, F; Flood, K; Gray, L; Grogg, K S; Grothe, M; Hall-Wilton, R; Jaworski, M; Klabbers, P; Klukas, J; Lanaro, A; Lazaridis, C; Leonard, J; Loveless, R; Magrans de Abril, M; Mohapatra, A; Ott, G; Polese, G; Reeder, D; Savin, A; Smith, W H; Sourkov, A; Swanson, J; Weinberg, M; Wenman, D; Wensveen, M; White, A

    2010-01-01

    The CMS Level-1 trigger was used to select cosmic ray muons and LHC beam events during data-taking runs in 2008, and to estimate the level of detector noise. This paper describes the trigger components used, the algorithms that were executed, and the trigger synchronisation. Using data from extended cosmic ray runs, the muon, electron/photon, and jet triggers have been validated, and their performance evaluated. Efficiencies were found to be high, resolutions were found to be good, and rates as expected.

  3. Analysis of Surface Texturization of Solar Cells by Molecular Dynamics Simulations

    Directory of Open Access Journals (Sweden)

    Hsiao-Yen Chung

    2008-01-01

    Full Text Available The purpose of this paper is to develop a simple new model, based on the classic molecular dynamics simulation (MD, alternative to complex electron-photon interactions to analyze the surface texturization of solar cells. This methodology can easily propose the absorptance differences between texturing and nontexturing solar cells. To verify model feasibility, this study simulates square, pyramidal, and semicircular texturization surfaces. Simulations show that surface texturization effectively increases the absorptance of incident light for solar cells, and this paper presents optimal texturization shapes. The MD model can also be potentially used to predict the efficiency promotion in any optical reflection-absorption cases.

  4. Efficient Surface Enhanced Raman Scattering substrates from femtosecond laser based fabrication

    Science.gov (United States)

    Parmar, Vinod; Kanaujia, Pawan K.; Bommali, Ravi Kumar; Vijaya Prakash, G.

    2017-10-01

    A fast and simple femtosecond laser based methodology for efficient Surface Enhanced Raman Scattering (SERS) substrate fabrication has been proposed. Both nano scaffold silicon (black silicon) and gold nanoparticles (Au-NP) are fabricated by femtosecond laser based technique for mass production. Nano rough silicon scaffold enables large electromagnetic fields for the localized surface plasmons from decorated metallic nanoparticles. Thus giant enhancement (approximately in the order of 104) of Raman signal arises from the mixed effects of electron-photon-phonon coupling, even at nanomolar concentrations of test organic species (Rhodamine 6G). Proposed process demonstrates the low-cost and label-less application ability from these large-area SERS substrates.

  5. Kohn-Sham approach to quantum electrodynamical density-functional theory: Exact time-dependent effective potentials in real space.

    Science.gov (United States)

    Flick, Johannes; Ruggenthaler, Michael; Appel, Heiko; Rubio, Angel

    2015-12-15

    The density-functional approach to quantum electrodynamics extends traditional density-functional theory and opens the possibility to describe electron-photon interactions in terms of effective Kohn-Sham potentials. In this work, we numerically construct the exact electron-photon Kohn-Sham potentials for a prototype system that consists of a trapped electron coupled to a quantized electromagnetic mode in an optical high-Q cavity. Although the effective current that acts on the photons is known explicitly, the exact effective potential that describes the forces exerted by the photons on the electrons is obtained from a fixed-point inversion scheme. This procedure allows us to uncover important beyond-mean-field features of the effective potential that mark the breakdown of classical light-matter interactions. We observe peak and step structures in the effective potentials, which can be attributed solely to the quantum nature of light; i.e., they are real-space signatures of the photons. Our findings show how the ubiquitous dipole interaction with a classical electromagnetic field has to be modified in real space to take the quantum nature of the electromagnetic field fully into account.

  6. Progress in electronics and photonics with nanomaterials

    DEFF Research Database (Denmark)

    Mishra, Yogendra Kumar; Murugan, Arul; Kotakoski, Jani

    2017-01-01

    Nanomaterials have been at the center of attraction for almost five decades as their contributions to different disciplines such as electronics, photonics and medicine are enormous. Various kinds of nanomaterials have been developed and are currently utilized in innumerable applications. Neverthe......Nanomaterials have been at the center of attraction for almost five decades as their contributions to different disciplines such as electronics, photonics and medicine are enormous. Various kinds of nanomaterials have been developed and are currently utilized in innumerable applications....... Nevertheless, their simple realization and easy and efficient upscaling are topics under intense investigation. Innovative strategies have been adopted for nanomaterial synthesis and their usability. Here, we provide a brief overview on nanomaterials ranging from basic understanding of their structure......-property relationship to advanced applications. This editorial covers various aspects about nanomaterials, which will be useful/attractive for beginners in the field of nanotechnology as well as for experts and for industrialists looking forward to exploit them for real world applications....

  7. Triggering on electrons and photons with CMS

    Directory of Open Access Journals (Sweden)

    Zabi Alexandre

    2012-06-01

    Full Text Available Throughout the year 2011, the Large Hadron Collider (LHC has operated with an instantaneous luminosity that has risen continually to around 4 × 1033cm−2s−1. With this prodigious high-energy proton collisions rate, efficient triggering on electrons and photons has become a major challenge for the LHC experiments. The Compact Muon Solenoid (CMS experiment implements a sophisticated two-level online selection system that achieves a rejection factor of nearly 106. The first level (L1 is based on coarse information coming from the calorimeters and the muon detectors while the High-Level Trigger (HLT combines fine-grain information from all sub-detectors. In this intense hadronic environment, the L1 electron/photon trigger provides a powerful tool to select interesting events. It is based upon information from the Electromagnetic Calorimeter (ECAL, a high-resolution detector comprising 75848 lead tungstate (PbWO4 crystals in a “barrel” and two “endcaps”. The performance as well as the optimization of the electron/photon trigger are presented.

  8. Design and Simulation of Photoneutron Source by MCNPX Monte Carlo Code for Boron Neutron Capture Therapy

    Directory of Open Access Journals (Sweden)

    Mona Zolfaghari

    2015-07-01

    Full Text Available Introduction Electron linear accelerator (LINAC can be used for neutron production in Boron Neutron Capture Therapy (BNCT. BNCT is an external radiotherapeutic method for the treatment of some cancers. In this study, Varian 2300 C/D LINAC was simulated as an electron accelerator-based photoneutron source to provide a suitable neutron flux for BNCT. Materials and Methods Photoneutron sources were simulated, using MCNPX Monte Carlo code. In this study, a 20 MeV LINAC was utilized for electron-photon reactions. After the evaluation of cross-sections and threshold energies, lead (Pb, uranium (U and beryllium deuteride (BeD2were selected as photoneutron sources. Results According to the simulation results, optimized photoneutron sources with a compact volume and photoneutron yields of 107, 108 and 109 (n.cm-2.s-1 were obtained for Pb, U and BeD2 composites. Also, photoneutrons increased by using enriched U (10-60% as an electron accelerator-based photoneutron source. Conclusion Optimized photoneutron sources were obtained with compact sizes of 107, 108 and 109 (n.cm-2.s-1, respectively. These fluxs can be applied for BNCT by decelerating fast neutrons and using a suitable beam-shaping assembly, surrounding electron-photon and photoneutron sources.

  9. Quantum state transfer between valley and photon qubits

    Science.gov (United States)

    Yang, Ming-Jay; Peng, Han-Ying; Na, Neil; Wu, Yu-Shu

    2017-02-01

    The electron-photon interaction in two-dimensional materials obeys the rule of "electron valley-photon polarization" correspondence. At the quantum level, such correspondence can be utilized to entangle valleys and polarizations and attain the transfer of quantum states (or information) between valley and photon qubits. Our paper presents a theoretical study of the interaction between the two types of qubits and the resultant quantum state transfer. A generic setup is introduced, which involves optical cavities enhancing the electron-photon interaction as well as facilitating both the entanglement and unentanglement between valleys and polarizations required by the transfer. The quantum system considered consists of electrons, optically excited trions, and cavity photons, with photons moving in and out of the system. A wave equation based analysis is performed, and analytical expressions are derived for the two important figures of merits that characterize the transfer, namely, yield and fidelity, allowing for the investigation of their dependences on various qubit and cavity parameters. A numerical study of the yield and fidelity has also been carried out. Overall, this paper shows promising characteristics in the valley-photon state transfer, with the conclusion that the valley-polarization correspondence can be exploited to achieve the transfer with good yield and high fidelity.

  10. Design and Simulation of Photoneutron Source by MCNPX Monte Carlo Code for Boron Neutron Capture Therapy

    Directory of Open Access Journals (Sweden)

    Mona Zolfaghari

    2015-07-01

    Full Text Available Introduction Electron linear accelerator (LINAC can be used for neutron production in Boron Neutron Capture Therapy (BNCT. BNCT is an external radiotherapeutic method for the treatment of some cancers. In this study, Varian 2300 C/D LINAC was simulated as an electron accelerator-based photoneutron source to provide a suitable neutron flux for BNCT. Materials and Methods Photoneutron sources were simulated, using MCNPX Monte Carlo code. In this study, a 20 MeV LINAC was utilized for electron-photon reactions. After the evaluation of cross-sections and threshold energies, lead (Pb, uranium (U and beryllium deuteride (BeD2were selected as photoneutron sources. Results According to the simulation results, optimized photoneutron sources with a compact volume and photoneutron yields of 107, 108 and 109 (n.cm-2.s-1 were obtained for Pb, U and BeD2 composites. Also, photoneutrons increased by using enriched U (10-60% as an electron accelerator-based photoneutron source. Conclusion Optimized photoneutron sources were obtained with compact sizes of 107, 108 and 109 (n.cm-2.s-1, respectively. These fluxs can be applied for BNCT by decelerating fast neutrons and using a suitable beam-shaping assembly, surrounding electron-photon and photoneutron sources.

  11. Spalax™ new generation: A sensitive and selective noble gas system for nuclear explosion monitoring.

    Science.gov (United States)

    Le Petit, G; Cagniant, A; Gross, P; Douysset, G; Topin, S; Fontaine, J P; Taffary, T; Moulin, C

    2015-09-01

    In the context of the verification regime of the Comprehensive nuclear Test ban Treaty (CTBT), CEA is developing a new generation (NG) of SPALAX™ system for atmospheric radioxenon monitoring. These systems are able to extract more than 6cm(3) of pure xenon from air samples each 12h and to measure the four relevant xenon radioactive isotopes using a high resolution detection system operating in electron-photon coincidence mode. This paper presents the performances of the SPALAX™ NG prototype in operation at Bruyères-le-Châtel CEA centre, integrating the most recent CEA developments. It especially focuses on an innovative detection system made up of a gas cell equipped with two face-to-face silicon detectors associated to one or two germanium detectors. Minimum Detectable activity Concentrations (MDCs) of environmental samples were calculated to be approximately 0.1 mBq/m(3) for the isotopes (131m)Xe, (133m)Xe, (133)Xe and 0.4 mBq/m(3) for (135)Xe (single germanium configuration). The detection system might be used to simultaneously measure particulate and noble gas samples from the CTBT International Monitoring System (IMS). That possibility could lead to new capacities for particulate measurements by allowing electron-photon coincidence detection of certain fission products.

  12. Monolithically Integrated Ge-on-Si Active Photonics

    Directory of Open Access Journals (Sweden)

    Jifeng Liu

    2014-07-01

    Full Text Available Monolithically integrated, active photonic devices on Si are key components in Si-based large-scale electronic-photonic integration for future generations of high-performance, low-power computation and communication systems. Ge has become an interesting candidate for active photonic devices in Si photonics due to its pseudo-direct gap behavior and compatibility with Si complementary metal oxide semiconductor (CMOS processing. In this paper, we present a review of the recent progress in Ge-on-Si active photonics materials and devices for photon detection, modulation, and generation. We first discuss the band engineering of Ge using tensile strain, n-type doping, Sn alloying, and separate confinement of Γ vs. L electrons in quantum well (QW structures to transform the material towards a direct band gap semiconductor for enhancing optoelectronic properties. We then give a brief overview of epitaxial Ge-on-Si materials growth, followed by a summary of recent investigations towards low-temperature, direct growth of high crystallinity Ge and GeSn alloys on dielectric layers for 3D photonic integration. Finally, we review the most recent studies on waveguide-integrated Ge-on-Si photodetectors (PDs, electroabsorption modulators (EAMs, and laser diodes (LDs, and suggest possible future research directions for large-scale monolithic electronic-photonic integrated circuits on a Si platform.

  13. Gauge-invariant dynamical quantities of QED with decomposed gauge potentials

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Baohua [Institute of Theoretical Physics, Beijing University of Technology, Beijing 100124 (China); Huang Yongchang [Institute of Theoretical Physics, Beijing University of Technology, Beijing 100124 (China); Kavli Institute for Theoretical Physics China, CAS, Beijing 100080 (China); CCAST (World Lab.), P.O. Box 8730, Beijing 100080 (China)

    2011-09-15

    We discover an inner structure of the QED system; i.e., by decomposing the gauge potential into two orthogonal components, we obtain a new expansion of the Lagrangian for the electron-photon system, from which, we realize the orthogonal decomposition of the canonical momentum conjugate to the gauge potential with the canonical momentum's two components conjugate to the gauge potential's two components, respectively. Using the new expansion of Lagrangian and by the general method of field theory, we naturally derive the gauge invariant separation of the angular momentum of the electron-photon system from Noether theorem, which is the rational one and has the simplest form in mathematics, compared with the other four versions of the angular momentum separation available in literature. We show that it is only the longitudinal component of the gauge potential that is contained in the orbital angular momentum of the electron, as Chen et al. have said. A similar gauge invariant separation of the momentum is given. The decomposed canonical Hamiltonian is derived, from which we construct the gauge invariant energy operator of the electron moving in the external field generated by a proton [Phys. Rev. A 82, 012107 (2010)], where we show that the form of the kinetic energy containing the longitudinal part of the gauge potential is due to the intrinsic requirement of the gauge invariance. Our method provides a new perspective to look on the nucleon spin crisis and indicates that this problem can be solved strictly and systematically.

  14. Correlated Light-Matter Interactions in Cavity QED

    Science.gov (United States)

    Flick, Johannes; Pellegrini, Camilla; Ruggenthaler, Michael; Appel, Heiko; Tokatly, Ilya; Rubio, Angel

    2015-03-01

    In the last decade, time-dependent density functional theory (TDDFT) has been successfully applied to a large variety of problems, such as calculations of absorption spectra, excitation energies, or dynamics in strong laser fields. Recently, we have generalized TDDFT to also describe electron-photon systems (QED-TDDFT). Here, matter and light are treated on an equal quantized footing. In this work, we present the first numerical calculations in the framework of QED-TDDFT. We show exact solutions for fully quantized prototype systems consisting of atoms or molecules placed in optical high-Q cavities and coupled to quantized electromagnetic modes. We focus on the electron-photon exchange-correlation (xc) contribution by calculating exact Kohn-Sham potentials using fixed-point inversions and present the performance of the first approximated xc-potential based on an optimized effective potential (OEP) approach. Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, and Fritz-Haber-Institut der MPG, Berlin

  15. Thermal entanglement between π-electrons in silicene and photons; occurrence of phase transitions

    Science.gov (United States)

    Rastgoo, S.; Golshan, M. M.

    2017-03-01

    In this article, the thermal entanglement between π-electronic states in a monolayer silicene sheet and a single mode quantized electromagnetic field is investigated. We assume that the system is in thermal equilibrium with the environment at a temperature T, so that the whole system is described by the Boltzmann distribution. Using the states of total Hamiltonian, the thermal density matrix and, consequently, its partially transposed one is computed, giving rise to the determination of negativity. Our analytical calculations, along with representative figures, show that the system is separable at zero temperature, exhibits a maximum, at a specific temperature, and asymptotically vanishes. Along these lines we also report the effects of electron-photon coupling, as well as the silicene buckling, on the entanglement. Specifically, we demonstrate that the maximal value of entanglement is larger for stronger electron-photon coupling, while it decreases for larger buckling effect. Moreover, we show that the gap in the total energy spectrum remains intact for any value of the buckling parameter. There is, however, one state whose energy changes sign, at a specific buckling, indicating a change of phase.

  16. Characterization of 2 MeV, 4 MeV, 6 MeV and 18 MeV buildup caps for use with a 0.6 cubic centimeter thimble ionization chamber

    Energy Technology Data Exchange (ETDEWEB)

    Salyer, R.L.; VanDenburg, J.W.; Prinja, A.K.; Kirby, T.; Busch, R. [Univ. of New Mexico, Albuquerque, NM (United States); Hong-Nian Jow [Sandia National Laboratories, Albuquerque, NM (United States)

    1996-07-01

    The purpose of this research is to characterize existing 2 MeV, 4 MeV and 6 MeV buildup caps, and to determine if a buildup cap can be made for the 0.6 cm{sup 3} thimble ionization chamber that will accurately measure exposures in a high-energy photon radiation field. Two different radiation transport codes were used to computationally characterize existing 2 MeV, 4 MeV, and 6 MeV buildup caps for a 0.6 cm{sup 3} active volume thimble ionization chamber: ITS, The Integrated TIGER Series of Coupled Electron-Photon Monte Carlo Transport Codes; and CEPXS/ONEDANT, A One-Dimensional Coupled Electron-Photon Discrete Ordinates Code Package. These codes were also used to determine the design characteristics of a buildup cap for use in the 18 MeV photon beam produced by the 14 TW pulsed power HERMES-III electron accelerator. The maximum range of the secondary electron, the depth at which maximum dose occurs, and the point where dose and collision kerma are equal have been determined to establish the validity of electronic equilibrium. The ionization chamber with the appropriate buildup cap was then subjected to a 4 MeV and a 6 MeV bremmstrahlung radiation spectrum to determine the detector response.

  17. Ge-on-Si optoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jifeng, E-mail: Jifeng.Liu@Dartmouth.edu [Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 (United States); Camacho-Aguilera, Rodolfo; Bessette, Jonathan T.; Sun, Xiaochen [Microphotonics Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Wang Xiaoxin [Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 (United States); Cai Yan; Kimerling, Lionel C.; Michel, Jurgen [Microphotonics Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2012-02-01

    Electronic-photonic synergy has become an increasingly clear solution to enhance the bandwidth and improve the energy efficiency of information systems. Monolithic integration of optoelectronic devices is the ideal solution for large-scale electronic-photonic synergy. Due to its pseudo-direct gap behavior in optoelectronic properties and compatibility with Si electronics, epitaxial Ge-on-Si has become an attractive solution for monolithic optoelectronics. In this paper we will review recent progress in Ge-on-Si optoelectronics, including photodetectors, electroabsorption modulators, and lasers. The performance of these devices has been enhanced by band-engineering such as tensile strain and n-type doping, which transforms Ge towards a direct gap material. Selective growth reduces defect density and facilitates monolithic integration at the same time. Ge-on-Si photodetectors have approached or exceeded the performance of their III-V counterparts, with bandwidth-efficiency product > 30 GHz for p-i-n photodiodes and bandwidth-gain product > 340 GHz for avalanche photodiodes. Enhanced Franz-Keldysh effect in tensile-strained Ge offers ultralow energy photonic modulation with < 30 fJ/bit energy consumption and > 100 GHz intrinsic bandwidth. Room temperature optically-pumped lasing as well as electroluminescence has also been achieved from the direct gap transition of band-engineered Ge-on-Si waveguides. These results indicate that band-engineered Ge-on-Si is promising to achieve monolithic active optoelectronic devices on a Si platform.

  18. Study of intersubband transitions in GaN-ZnGeN2 coupled quantum wells

    Science.gov (United States)

    Han, Lu; Lieberman, Colin; Zhao, Hongping

    2017-03-01

    In this work, we design and analyze a closely lattice-matched wide bandgap GaN-ZnGeN2 coupled quantum well (QW) structure targeting for near-infrared (IR) (λ ≤ 3 um) intersubband transition for quantum cascade laser applications. The coupled quantum well structure comprised two GaN wells separated by a thin ZnGeN2 barrier layer. The QW active region is surrounded by thick ZnGeN2 layers as barriers. The computations of the electron-phonon and electron-photon scattering rates are carried out by employing the Fermi's golden rule for transitions. The calculation takes into consideration the conservation of energy and momentum in scattering processes. The coupled QW structure is optimized through tuning the confined subband energy levels in the conduction band to achieve (1) electron-LO phonon resonant scattering when the energy separation between the first and second conduction subband levels matches the phonon energy of GaN (92 meV); and (2) dominant electron-photon transition in near-IR between the third and second conduction subband levels.

  19. Optimisation of the level-1 calorimeter trigger at ATLAS for Run II

    Energy Technology Data Exchange (ETDEWEB)

    Suchek, Stanislav [Kirchhoff-Institute for Physics, Im Neuenheimer Feld 227, 69120 Heidelberg (Germany); Collaboration: ATLAS-Collaboration

    2015-07-01

    The Level-1 Calorimeter Trigger (L1Calo) is a central part of the ATLAS Level-1 Trigger system, designed to identify jet, electron, photon, and hadronic tau candidates, and to measure their transverse energies, as well total transverse energy and missing transverse energy. The optimisation of the jet energy resolution is an important part of the L1Calo upgrade for Run II. A Look-Up Table (LUT) is used to translate the electronic signal from each trigger tower to its transverse energy. By optimising the LUT calibration we can achieve better jet energy resolution and better performance of the jet transverse energy triggers, which are vital for many physics analyses. In addition, the improved energy calibration leads to significant improvements of the missing transverse energy resolution. A new Multi-Chip Module (MCM), as a part of the L1Calo upgrade, provides two separate LUTs for jets and electrons/photons/taus, allowing to optimise jet transverse energy and missing transverse energy separately from the electromagnetic objects. The optimisation is validated using jet transverse energy and missing transverse energy triggers turn-on curves and rates.

  20. Quantitative evaluation of patient setup uncertainty of stereotactic radiotherapy with the frameless 6D ExacTrac system using statistical modeling.

    Science.gov (United States)

    Keeling, Vance; Hossain, Sabbir; Jin, Hosang; Algan, Ozer; Ahmad, Salahuddin; Ali, Imad

    2016-05-08

    The purpose of this study is to evaluate patient setup accuracy and quantify indi-vidual and cumulative positioning uncertainties associated with different hardware and software components of the stereotactic radiotherapy (SRS/SRT) with the frameless 6D ExacTrac system. A statistical model is used to evaluate positioning uncertainties of the different components of SRS/SRT treatment with the Brainlab 6D ExacTrac system using the positioning shifts of 35 patients having cranial lesions. All these patients are immobilized with rigid head-and-neck masks, simu-lated with Brainlab localizer and planned with iPlan treatment planning system. Stereoscopic X-ray images (XC) are acquired and registered to corresponding digitally reconstructed radiographs using bony-anatomy matching to calculate 6D translational and rotational shifts. When the shifts are within tolerance (0.7 mm and 1°), treatment is initiated. Otherwise corrections are applied and additional X-rays (XV) are acquired to verify that patient position is within tolerance. The uncertain-ties from the mask, localizer, IR -frame, X-ray imaging, MV, and kV isocentricity are quantified individually. Mask uncertainty (translational: lateral, longitudinal, vertical; rotational: pitch, roll, yaw) is the largest and varies with patients in the range (-2.07-3.71 mm, -5.82-5.62 mm, -5.84-3.61 mm; -2.10-2.40°, -2.23-2.60°, and -2.7-3.00°) obtained from mean of XC shifts for each patient. Setup uncer-tainty in IR positioning (0.88, 2.12, 1.40 mm, and 0.64°, 0.83°, 0.96°) is extracted from standard deviation of XC. Systematic uncertainties of the frame (0.18, 0.25, -1.27mm, -0.32°, 0.18°, and 0.47°) and localizer (-0.03, -0.01, 0.03mm, and -0.03°, 0.00°, -0.01°) are extracted from means of all XV setups and mean of all XC distributions, respectively. Uncertainties in isocentricity of the MV radiotherapy machine are (0.27, 0.24, 0.34 mm) and kV imager (0.15, -0.4, 0.21 mm). A statisti-cal model is developed to

  1. Locoregional Treatment for Breast Carcinoma After Hodgkin's Lymphoma: The Breast Conservation Option

    Energy Technology Data Exchange (ETDEWEB)

    Haberer, Sophie, E-mail: sophie.haberer@wanadoo.fr [Department of Radiation Oncology, Institut Curie, Paris (France); Belin, Lisa [Department of Biostatistics, Institut Curie, Paris (France); Le Scodan, Romuald; Kirova, Youlia M. [Department of Radiation Oncology, Institut Curie, Paris (France); Savignoni, Alexia; Stevens, Denise [Department of Biostatistics, Institut Curie, Paris (France); Moisson, Patricia [Department of Radiation Oncology, Institut Curie, Paris (France); Decaudin, Didier; Pierga, Jean-Yves [Department of Medical Oncology, Institut Curie, Paris (France); Reyal, Fabien [Department of Surgery, Institut Curie, Paris (France); Campana, Francois; Fourquet, Alain; Bollet, Marc A. [Department of Radiation Oncology, Institut Curie, Paris (France)

    2012-02-01

    Purpose: To report clinical and pathologic characteristics and outcome of breast cancer (BC) after irradiation for Hodgkin's lymphoma (HL) in women treated at the Institut Curie, with a special focus on the breast-conserving option. Methods and Materials: Medical records of 72 women who developed either ductal carcinoma in situ or Stage I-III invasive carcinoma of the breast after HL between 1978 and 2009 were retrospectively reviewed. Results: Median age at HL diagnosis was 23 years (range, 14-53 years). Median total dose received by the mediastinum was 40 Gy, mostly by a mantle-field technique. Breast cancers occurred after a median interval of 21 years (range, 5-40 years). Ductal invasive carcinoma and ductal carcinoma in situ represented, respectively, 51 cases (71%) and 14 cases (19%). Invasive BCs consisted of 47 cT0-2 tumors (82%), 5 cN1-3 tumors (9%), and 20 Grade 3 tumors (35%). Locoregional treatment for BCs consisted of mastectomy with (3) or without (36) radiotherapy in 39 patients and lumpectomy with (30) or without (2) adjuvant radiotherapy in 32 patients. The isocentric lateral decubitus radiation technique was used in 17 patients after breast-conserving surgery (57%). With a median follow-up of 7 years, 5-year overall survival rate and locoregional control rate were, respectively, 74.5% (95% confidence interval [CI], 64-88%) and 82% (95% CI, 72-93%) for invasive carcinoma and 100% (95% CI, 100 -100%) and 92% (95% CI, 79-100%) for in situ carcinoma. In patients with invasive tumors, the 5-year distant disease-free survival rate was 79% (95% CI, 69-91%), and 13 patients died of progressive BC. Contralateral BC was diagnosed in 10 patients (14%). Conclusions: Breast-conserving treatment can be an option for BCs that occur after HL, despite prior thoracic irradiation. It should consist of lumpectomy and adjuvant breast radiotherapy with use of adequate techniques, such as the lateral decubitus isocentric position, to protect the underlying heart

  2. SU-E-T-229: Craniospinal Radiotherapy Planning with VMAT, Two First Years Experience

    Energy Technology Data Exchange (ETDEWEB)

    Lliso, F; Carmona, V; Gimeno, J; Candela-Juan, C; Bautista, J [La Fe University and Polytechnic Hospital, Valencia, Valencia (Spain); Richart, J [ITIC, Hospital Clinica Benidorm, Benidorm, Alicante (Spain); Perez-Calatayud, J [La Fe University and Polytechnic Hospital, Valencia, Valencia (Spain); ITIC, Hospital Clinica Benidorm, Benidorm, Alicante (Spain)

    2015-06-15

    Purpose: To describe how we moved to VMAT in the craniospinal radiotherapy planning process, the actual procedure details, and the results for the patients treated. Methods: Twelve patients underwent craniospinal irradiation with the new procedure, based on the paper by Lee et al. (IJROBP 82, 2012), with some additional modifications. Patients were treated in supine position in Varian Clinac iX linacs with 6 MV RapidArc; prescription doses ranged from 23.4 to 40 Gy (13 to 20 fractions); depending on the PTV length, 2 or 3 isocenters were used, all coordinates being equal except the longitudinal one, setting a few centimeter-long overlapping region; 2 arcs (RA) sharing isocentre for the cranial region, RA1 encompassing cranium and superior spinal region, and RA2 intended to improve conformity, only for cranium; for spine, 1 or 2 isocenters were employed; optimization was performed with Eclipse (V 13.0) using AAA algorithm, establishing sets of optimization parameters to give high conformity while sparing OAR. In pediatric patients, homogeneous irradiation of the vertebrae was also required.Conformity (CI) and heterogeneity (HI) indices (same as Lee et al.), and mean and maximum doses for OAR were calculated. Several pre-treatment verification methods were used: Octavius4D (PTW) for each isocentre, point dose at the junction region, Portal Dosimetry (when possible), and independent MU verification software (Diamond, PTW). Results: CI median value was 1.02 (0.99–1.07) and HI, 1.07 (1.06–1.09); a great reduction was observed for CI and OAR mean doses with respect to Lee et al. data; median maximum eye lens dose was 7.3 Gy (4.0–12.0); mean LungV20Gy was 1.9%; in children, vertebrae were homogeneously irradiated (D95%=20.8 Gy, Dmean= 23.2 Gy).All pre-treatment verifications were found within our action levels except for Portal Dosimetry. Conclusion: A RapidArc planning process for craniospinal axis irradiation has been implemented with significant advantages on

  3. SU-E-J-213: Imaging and Treatment Isocenter Verification of a Gantry Mounted Proton Therapy System

    Energy Technology Data Exchange (ETDEWEB)

    Price, S; Goddu, S; Rankine, L; Klein, E [Washington University, St. Louis, MO (United States)

    2014-06-01

    Purpose: The Mevion proton therapy machine is the first to feature a gantry mounted sychro-cyclotron. In addition, the system utilizes a 6D motion couch and kV imaging for precise proton therapy. To quantify coincidence between these systems, isocentricity tests were performed based on kV imaging alignment using radiochromic film. Methods: The 100 ton gantry and 6D robotic couch can rotate 190° around isocenter to provide necessary beam angles for treatment. The kV sources and detector panels are deployed as needed to acquire orthogonal portals. Gantry and couch mechanical isocenter were tested using star-shots and radiochromic-film (RCF). Using kV imaging, the star-shot phantom was aligned to an embedded fiducial and the isocenter was marked on RCF with a pinprick. The couch and gantry stars were performed by irradiating films at every 45° and 30°, respectively. A proton beam with a range and modulation-width of 18 cm was used. A Winston-Lutz test was also performed at the same gantry and couch rotations using a custom jig holding RCF and a tungsten ball placed at isocenter. A 2 cm diameter circular aperture was used for the irradiation. Results: The couch star-shot indicated a minimum tangent circle of 0.6 mm, with a 0.9 mm offset from the manually marked isocenter. The gantry star-shot showed a 0.6 mm minimum tangent circle with a 0.5 mm offset from the pinprick. The Winston Lutz test performed for gantry rotation showed a maximum deviation from center of 0.5 mm. Conclusion: Based on star-shots and Winston-Lutz tests, the proton gantry and 6D couch isocentricity are within 1 mm. In this study, we have shown that the methods commonly utilized for Linac characterization can be applied to proton therapy. This revolutionary proton therapy system possesses excellent agreement between the mechanical and radiation isocenter, providing highly precise treatment.

  4. SU-E-T-648: Quality Assurance Using the RADPOS System for 4D Radiotherapy with CyberKnife

    Energy Technology Data Exchange (ETDEWEB)

    Marants, R [Department of Physics, Carleton University, Ottawa, ON (Canada); Vandervoort, E [Department of Medical Physics, The Ottawa Hospital Cancer Centre, Ottawa, ON (Canada); Cygler, J E [Department of Physics, Carleton University, Ottawa, ON (Canada); Department of Medical Physics, The Ottawa Hospital Cancer Centre, Ottawa, ON (Canada); Department of Radiology, University of Ottawa, Ottawa, ON (Canada)

    2015-06-15

    Purpose: The CyberKnife robotic radiosurgery system uses Synchrony respiratory motion compensation, which requires independent performance verification. In this work, the RADPOS 4D dosimetry system’s motion measurements are compared with internal fiducial position measurements. In addition, RADPOS measurements are compared with Synchrony’s predictive correlation model, which is based on internal fiducial and external LED marker position measurements. Methods: A treatment plan was created for a lung insert containing fiducials, RADPOS detector, and Solid Water tumor phantom. Two Quasar Respiratory Motion Phantoms (Q1 and Q2) and two RADPOS detectors (R1 and R2) were used: Q1 simulated lung motion with a lung insert moving in the superior/inferior direction, while Q2 simulated chest motion with a chest platform moving in the anterior/posterior direction. Before treatment, R1 was secured inside of the tumor phantom within Q1, while LED markers and R2 were positioned on the chest platform of Q2. Two treatment delivery cases were studied: isocentric plan (I) and non-isocentric patient plan (P). Four motion cases were studied: no motion (0), sinusoidal and in-phase (1), sinusoidal and out-of-phase (2), patient waveform and out-of-phase (3). A coordinate alignment algorithm was implemented, allowing RADPOS and model position data to be compared within the fiducial coordinate system. Results: The standard deviation of the differences between RADPOS and fiducial position measurements was below 0.6 mm for all experimental cases. The standard deviation of the differences between RADPOS and model position data was 1.0, 1.5, and 1.6 mm along the primary direction of motion for case I1, I2, and P3, respectively. Conclusion: Our work demonstrates that RADPOS is a useful tool for independent quality assurance of CyberKnife treatment with Synchrony respiratory compensation. RADPOS and fiducial position measurement closely match, and RADPOS confirms the effectiveness of Cyber

  5. SU-E-T-80: Comparison of Fluence-Based RapidArc QAs Using EPID and MapCHECK 2

    Energy Technology Data Exchange (ETDEWEB)

    Jin, H; Jesseph, F; Ahmad, S [Oklahoma Univ. Health Science Ctr., Oklahoma City, OK (United States)

    2014-06-01

    Purpose: To compare the Varian aS-1000 EPID imager to the isocentrically mounted MapCHECK 2 diode array for RapidArc QAs as a function of photon beam energy. Methods: A Varian TrueBeam STx with an aS-1000 digital imaging panel was used to acquire RapidArc QA images for 13 patient plans; each plan QA was performed at 6, 8, 10 and 15MV energies. The Portal Dose Image Prediction algorithm in the Varian Eclipse treatment planning system (TPS) was used to create the comparison image for the EPID acquisition. A Sun Nuclear MapCHECK 2 diode array on an isocentric mounting fixture with 5 cm water-equivalent buildup was also used for the RapidArc QAs. A composite dose plane was taken from the Eclipse TPS for comparison to the MapCHECK 2 measurements. A gamma test was implemented in the Sun Nuclear Patient software with 10% threshold and absolute comparison for both QA methods. The two-tailed paired t-test was employed to analyze the statistical significance between two methods at the 95% confidence level. Results: The average gamma passing rates were greater than 95% at 3%/3mm using both methods for all four energies. The average passing rates were within 2.5% and 1.1% of each other when analyzed at 2%/2mm and 3%/3mm conditions, respectively. The EPID passing rates were somewhat better than the MapCHECK 2 when analyzed at 1%/1mm condition; this difference decreased with increasing energy (9.1% at 6MV to 2.7% at 15MV). The differences were not statistically significant for all criteria and energies (p-value ã 0.05). Conclusion: EPID-based RapidArc QA results are comparable to MapCHECK 2 when using 3%/3mm criteria at all four energies. EPID-based QA shows potential for being the superior device under strict gamma criteria.

  6. SU-E-T-539: Maximum Energy of Helium and Carbon Ions Clinically Needed for Spine, Lung, Prostate and Pancreas Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Pompos, A; Choy, H; Jia, X; Jiang, S; Timmerman, R [The University of Texas Southwestern Medical Ctr, Dallas, TX (United States)

    2015-06-15

    Purpose: Maximum available kinetic energy of accelerated heavy ions is a critical parameter to consider during the establishment of a heavy ion therapy center. It dictates the maximum range in tissue and determines the size and cost of ion gantry. We have started planning our heavy ion therapy center and we report on the needed ion range. Methods: We analyzed 50 of random SBRT-spine, SBRT- lung, prostate and pancreatic cancer patients from our photon clinic. In the isocentric axial CT cut we recorded the maximum water equivalent depth (WED4Field) of PTV’s most distal edge in four cardinal directions and also in a beam direction that required the largest penetration, WEDGantry. These depths were then used to calculate the percentage of our patients we would be able to treat as a function of available maximum carbon and helium beam energy. Based on the Anterior-Posterior WED for lung patients and the maximum available ion energy we estimated the largest possible non-coplanar beam entry angle φ (deviation from vertical) in the isocentric vertical sagittal plane. Results: We found that if 430MeV/u C-12, equivalently 220MeV/u He-4, beams are available, more than 96% (98%) of all patients can be treated without any gantry restrictions (in cardinals angles only) respectively. If the energy is reduced to 400MeV/u C-12, equivalently 205MeV/u He-4, the above fractions reduce to 80% (87%) for prostate and 88% (97%) for other sites. This 7% energy decrease translates to almost 5% gantry size and cost decrease for both ions. These energy limits in combination with the WED in the AP direction for lung patients resulted in average non-coplanar angles of φ430MeV/u = 68°±8° and φ400MeV/u = 65°±10° if nozzle clearance permits them. Conclusion: We found that the two worldwide most common maximum carbon beam energies will treat above 80% of all our patients.

  7. Improved volumetric imaging in tomosynthesis using combined multiaxial sweeps.

    Science.gov (United States)

    Gersh, Jacob A; Wiant, David B; Best, Ryan C M; Bennett, Marcus C; Munley, Michael T; King, June D; McKee, Mahta M; Baydush, Alan H

    2010-09-03

    This study explores the volumetric reconstruction fidelity attainable using tomosynthesis with a kV imaging system which has a unique ability to rotate isocentrically and with multiple degrees of mechanical freedom. More specifically, we seek to investigate volumetric reconstructions by combining multiple limited-angle rotational image acquisition sweeps. By comparing these reconstructed images with those of a CBCT reconstruction, we can gauge the volumetric fidelity of the reconstructions. In surgical situations, the described tomosynthesis-based system could provide high-quality volumetric imaging without requiring patient motion, even with rotational limitations present. Projections were acquired using the Digital Integrated Brachytherapy Unit, or IBU-D. A phantom was used which contained several spherical objects of varying contrast. Using image projections acquired during isocentric sweeps around the phantom, reconstructions were performed by filtered backprojection. For each image acquisition sweep configuration, a contrasting sphere is analyzed using two metrics and compared to a gold standard CBCT reconstruction. Since the intersection of a reconstructed sphere and an imaging plane is ideally a circle with an eccentricity of zero, the first metric presented compares the effective eccentricity of intersections of reconstructed volumes and imaging planes. As another metric of volumetric reconstruction fidelity, the volume of one of the contrasting spheres was determined using manual contouring. By comparing these manually delineated volumes with a CBCT reconstruction, we can gauge the volumetric fidelity of reconstructions. The configuration which yielded the highest overall volumetric reconstruction fidelity, as determined by effective eccentricities and volumetric contouring, consisted of two orthogonally-offset 60° L-arm sweeps and a single C-arm sweep which shared a pivot point with one the L-arm sweeps. When compared to a similar configuration that

  8. Portal dosimetry for VMAT using integrated images obtained during treatment.

    Science.gov (United States)

    Bedford, James L; Hanson, Ian M; Hansen, Vibeke Nordmark

    2014-02-01

    Portal dosimetry provides an accurate and convenient means of verifying dose delivered to the patient. A simple method for carrying out portal dosimetry for volumetric modulated arc therapy (VMAT) is described, together with phantom measurements demonstrating the validity of the approach. Portal images were predicted by projecting dose in the isocentric plane through to the portal image plane, with exponential attenuation and convolution with a double-Gaussian scatter function. Appropriate parameters for the projection were selected by fitting the calculation model to portal images measured on an iViewGT portal imager (Elekta AB, Stockholm, Sweden) for a variety of phantom thicknesses and field sizes. This model was then used to predict the portal image resulting from each control point of a VMAT arc. Finally, all these control point images were summed to predict the overall integrated portal image for the whole arc. The calculated and measured integrated portal images were compared for three lung and three esophagus plans delivered to a thorax phantom, and three prostate plans delivered to a homogeneous phantom, using a gamma index for 3% and 3 mm. A 0.6 cm(3) ionization chamber was used to verify the planned isocentric dose. The sensitivity of this method to errors in monitor units, field shaping, gantry angle, and phantom position was also evaluated by means of computer simulations. The calculation model for portal dose prediction was able to accurately compute the portal images due to simple square fields delivered to solid water phantoms. The integrated images of VMAT treatments delivered to phantoms were also correctly predicted by the method. The proportion of the images with a gamma index of less than unity was 93.7% ± 3.0% (1SD) and the difference between isocenter dose calculated by the planning system and measured by the ionization chamber was 0.8% ± 1.0%. The method was highly sensitive to errors in monitor units and field shape, but less sensitive to

  9. SU-E-J-139: One Institution’s Experience with Surface Imaging in Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, L; Singh, H; Zheng, Y [ProCure Proton Therapy Center, Oklahoma City, OK (United States)

    2015-06-15

    Purpose: X-ray system is commonly used for IGRT in proton therapy, however image acquisition not only increases treatment time but also adds imaging dose. We studied a 3D surface camera system (AlignRT) performance for proton therapy. Methods: System accuracy was evaluated with rigid phantom under two different camera location configurations. For initial clinical applications, post mastectomy chest wall and partial breast treatments were studied. X-ray alignment was used as our ground truth. Our studies included: 1) comparison of daily patient setup shifts between X-ray alignment and SI calculation; 2) interfractional breast surface position variation when aligning to bony landmark on X-ray; 3) absolute positioning using planning CT DICOM data; 4) shifts for multi-isocenter treatment plan; 5) couch isocentric rotation accuracy. Results: Camera locations affected the system performance. After camera relocation, the accuracy of the system for the rigid phantom was within 1 mm (fixed couch), and 1.5 mm (isocentric rotation). For intrafractional patient positioning, X-ray and AlignRT shifts were highly correlated (r=0.99), with the largest difference (mean ± SD) in the longitudinal direction (2.14 ± 1.02 mm). For interfractional breast surface variation and absolute positioning, there were still larger disagreements between the two modalities due to different focus on anatomical landmarks, and 95% of the data lie within 5mm with some outliers at 7 mm–9 mm. For multi-isocenter shifts, the difference was 1 ± 0.56 mm over an 11 cm shift in longitudinal direction. For couch rotation study, the differences was 1.36 ± 1.0 mm in vertical direction, 3.04 ± 2.11 mm in longitudinal direction, and 2.10 ± 1.66 mm in lateral direction, with all rotation differences < 1.5 degree. Conclusion: Surface imaging is promising for intrafractional treatment application in proton therapy to reduce X-ray frequency. However the interfractional discrepancy between the X-ray and SI

  10. Radiosurgery in the management of brain metastasis: a retrospective single-center study comparing Gamma Knife and LINAC treatment.

    Science.gov (United States)

    Tuleasca, Constantin; Negretti, Laura; Faouzi, Mohamed; Magaddino, Vera; Gevaert, Thierry; von Elm, Erik; Levivier, Marc

    2017-03-24

    OBJECTIVE The authors present a retrospective analysis of a single-center experience with treatment of brain metastases using Gamma Knife (GK) and linear accelerator (LINAC)-based radiosurgery and compare the results. METHODS From July 2010 to July 2012, 63 patients with brain metastases were treated with radiosurgery. Among them, 28 (with 83 lesions) were treated with a GK unit and 35 (with 47 lesions) with a LINAC. The primary outcome was local progression-free survival (LPFS), evaluated on a per-lesion basis. The secondary outcome was overall survival (OS), evaluated per patient. Statistical analysis included standard tests and Cox regression with shared-frailty models to account for the within-patient correlation. RESULTS The mean follow-up period was 11.7 months (median 7.9 months, range 1.7-32 months) for GK and 18.1 months (median 17 months, range 7.5-28.7 months) for LINAC. The median number of lesions per patient was 2.5 (range 1-9) in the GK group and 1 (range 1-3) in the LINAC group (p 0.05). The mean OS was 16.0 months (95% CI 11.2-20.9 months) in the GK group, compared with 20.9 months (95% CI 16.4-25.3 months) in the LINAC group. Univariate and multivariate analysis showed that a lower graded prognostic assessment (GPA) score, noncontrolled systemic status at last radiological assessment, and older age were associated with lower OS; after adjustment of these covariables by Cox regression, the OS was similar in the 2 groups. CONCLUSIONS In this retrospective study comparing GK and LINAC-based radiosurgery for brain metastases, patients with more severe disease were treated by GK, including those harboring lesions of greater number, of radioresistant type, or in highly functional areas. The risk of local progression for the LINAC group was almost twice that in the GK group, although the difference was not statistically significant. Importantly, the OS rates were similar for the 2 groups, although GK was used in patients with more complex brain

  11. Evaluation of the peripheral dose to uterus in breast carcinoma radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Rincon, C.; Jerez Sainz, I.; Modelell Farre, I.; Espana Lopez, M.L.; Lopez Franco, P.; Muniz, J.L.; Romero, A.M.; Rodriguez, R

    2002-07-01

    The absorbed dose outside of the direct fields of radiotherapy treatment (or peripheral dose, PD) is responsible for radiation exposure of the fetus in pregnant women. Because the radiological protection of the unborn child is of particular concern in the early period of the pregnancy, the aim of this study is to estimate the PD in order to assess the absorbed dose in the uterus in a pregnant patient irradiated for breast carcinoma therapy. The treatment was simulated on an Alderson-Rando anthropomorphic phantom, and the radiation dose to the fetus was measured using an ionisation chamber and thermoluminescence dosemeters. Two similar treatments plans with and without wedges were delivered, using a 6 MV photon beam with two isocentric opposite tangential fields with a total dose of 50 Gy, in accordance with common established procedures. Average field parameters for more than 300 patients were studied. Measurements showed the fetal dose to be slightly lower than 50 mGy, a level at which the risk to the fetus is uncertain, although several authors consider this value as the dose threshold for deterministic effects. The planning system underestimated PD values and no significant influence was found with the use of wedge filters. (author)

  12. Monte Carlo optimization of total body irradiation in a phantom and patient geometry

    Science.gov (United States)

    Chakarova, R.; Müntzing, K.; Krantz, M.; Hedin, E.; Hertzman, S.

    2013-04-01

    The objective of this work is to apply a Monte Carlo (MC) accelerator model, validated by experimental data at isocentre distances, to a large-field total body irradiation (TBI) technique and to develop a strategy for individual patient treatment on the basis of MC dose distributions. Calculations are carried out using BEAMnrc/DOSXYZnrc code packages for a 15 MV Varian accelerator. Acceptable agreement is obtained between MC data and measurements in a large water phantom behind a spoiler at source-skin distances (SSD) = 460 cm as well as in a CIRS® thorax phantom. Dose distributions in patients are studied when simulating bilateral beam delivery at a distance of 480 cm to the patient central sagittal plane. A procedure for individual improvement of the dose uniformity is suggested including the design of compensators in a conventional treatment planning system (TPS) and a subsequent update of the dose distribution. It is demonstrated that the dose uniformity for the simple TBI technique can be considerably improved. The optimization strategy developed is straightforward and suitable for clinics where the TPS available is deficient to calculate 3D dose distributions at extended SSD.

  13. A small animal image guided irradiation system study using 3D dosimeters

    Science.gov (United States)

    Qian, Xin; Admovics, John; Wuu, Cheng-Shie

    2015-01-01

    In a high resolution image-guided small animal irradiation platform, a cone beam computed tomography (CBCT) is integrated with an irradiation unit for precise targeting. Precise quality assurance is essential for both imaging and irradiation components. The conventional commissioning techniques with films face major challenges due to alignment uncertainty and labour intensive film preparation and scanning. In addition, due to the novel design of this platform the mouse stage rotation for CBCT imaging is perpendicular to the gantry rotation for irradiation. Because these two rotations are associated with different mechanical systems, discrepancy between rotation isocenters exists. In order to deliver x-ray precisely, it is essential to verify coincidence of the imaging and the irradiation isocenters. A 3D PRESAGE dosimeter can provide an excellent tool for checking dosimetry and verifying coincidence of irradiation and imaging coordinates in one system. Dosimetric measurements were performed to obtain beam profiles and percent depth dose (PDD). Isocentricity and coincidence of the mouse stage and gantry rotations were evaluated with starshots acquired using PRESAGE dosimeters. A single PRESAGE dosimeter can provide 3 -D information in both geometric and dosimetric uncertainty, which is crucial for translational studies.

  14. Clinical Accuracy of Three-Dimensional Fluoroscopy (IsoC-3D-Assisted Upper Thoracic Pedicle Screw Insertion

    Directory of Open Access Journals (Sweden)

    Sugimoto,Yoshihisa

    2010-06-01

    Full Text Available Correct screw placement is especially difficult in the upper thoracic vertebrae. At the cervicothoracic junction (C7-T2, problems can arise because of the narrowness of the pedicle and the difficulty of using a lateral image intensifier there. Other upper thoracic vertebrae (T3-6 pose a problem for screw insertion also because of the narrower pedicle. We inserted 154 pedicle screws into 78 vertebrae (C7 to T6 in 38 patients. Screws were placed using intraoperative data acquisition by an isocentric C-arm fluoroscope (Siremobile Iso-C3D and computer navigation. Out of 90 pedicle screws inserted into 45 vertebrae between C7 and T2, 87 of the 90 (96.7% screws were classified as grade 1 (no perforation. Of 64 pedicle screws inserted into 33 vertebrae between T3 and T6, 61 of 64 (95.3% screws were classified as grade 1. In this study, we reduced pedicle screw misplacement at the level of the C7 and upper thoracic (T1-6 vertebrae using the three-dimensional fluoroscopy navigation system.

  15. Characterization of electron contamination in megavoltage photon beams.

    Science.gov (United States)

    Lopez Medina, Antonio; Teijeiro, Antonio; Garcia, Juan; Esperon, Jorge; Terron, J Antonio; Ruiz, Diego P; Carrion, Maria C

    2005-05-01

    The purpose of the present study is to characterize electron contamination in photon beams in different clinical situations. Variations with field size, beam modifier (tray, shaping block) and source-surface distance (SSD) were studied. Percentage depth dose measurements with and without a purging magnet and replacing the air by helium were performed to identify the two electron sources that are clearly differentiated: air and treatment head. Previous analytical methods were used to fit the measured data, exploring the validity of these models. Electrons generated in the treatment head are more energetic and more important for larger field sizes, shorter SSD, and greater depths. This difference is much more noticeable for the 18 MV beam than for the 6 MV beam. If a tray is used as beam modifier, electron contamination increases, but the energy of these electrons is similar to that of electrons coming from the treatment head. Electron contamination could be fitted to a modified exponential curve. For machine modeling in a treatment planning system, setting SSD at 90 cm for input data could reduce errors for most isocentric treatments, because they will be delivered for SSD ranging from 80 to 100 cm. For very small field sizes, air-generated electrons must be considered independently, because of their different energetic spectrum and dosimetric influence.

  16. Dummy run for a phase II study of stereotactic body radiotherapy of T1-T2 N0M0 medical inoperable non-small cell lung cancer

    DEFF Research Database (Denmark)

    Djärv, Emma; Nyman, Jan; Baumann, Pia;

    2006-01-01

    In forthcoming multicentre studies on stereotactic body radiotherapy       (SBRT) compliance with volume and dose prescriptions will be mandatory to       avoid unnecessary heterogeneity bias. To evaluate compliance in a       multicentre setting we used two cases from an ongoing phase II study......,       prescribing doses and creating dose plans. Volumes and doses of the 12       dose plans were evaluated according to the study protocol. For the two       patients the GTV volume range was 24 to 39 cm3 and 26 to 41 cm3,       respectively. The PTV volume range was 90 to 116 cm3, and 112 to 155 cm3......,       respectively. For all plans the margin between CTV and PTV in all       directions followed in detail the protocol. The prescribed dose was for       all centres 45 Gy/3 fractions (isocentre dose about 66 Gy). The mean GTV       doses ranged from 63 to 67 Gy and from 63 to 68 Gy, respectively...

  17. Multimodal imaging utilising integrated MR-PET for human brain tumour assessment

    Energy Technology Data Exchange (ETDEWEB)

    Neuner, Irene [Institute of Neuroscience and Medicine 4, INM 4, Juelich (Germany); RWTH Aachen University, Department of Psychiatry, Psychotherapy and Psychosomatics, Aachen (Germany); JARA-BRAIN-Translational Medicine, Aachen (Germany); Kaffanke, Joachim B. [Institute of Neuroscience and Medicine 4, INM 4, Juelich (Germany); MR-Transfer e.K., Wuppertal (Germany); Langen, Karl-Josef; Kops, Elena Rota; Tellmann, Lutz; Stoffels, Gabriele; Weirich, Christoph; Filss, Christian; Scheins, Juergen; Herzog, Hans [Institute of Neuroscience and Medicine 4, INM 4, Juelich (Germany); Shah, N. Jon [Institute of Neuroscience and Medicine 4, INM 4, Juelich (Germany); RWTH Aachen University, Department of Neurology, Aachen (Germany); JARA-BRAIN-Translational Medicine, Aachen (Germany)

    2012-12-15

    The development of integrated magnetic resonance (MR)-positron emission tomography (PET) hybrid imaging opens up new horizons for imaging in neuro-oncology. In cerebral gliomas the definition of tumour extent may be difficult to ascertain using standard MR imaging (MRI) only. The differentiation of post-therapeutic scar tissue, tumour rests and tumour recurrence is challenging. The relationship to structures such as the pyramidal tract to the tumour mass influences the therapeutic neurosurgical approach. The diagnostic information may be enriched by sophisticated MR techniques such as diffusion tensor imaging (DTI), multiple-volume proton MR spectroscopic imaging (MRSI) and functional MRI (fMRI). Metabolic imaging with PET, especially using amino acid tracers such as {sup 18}F-fluoroethyl-l-tyrosine (FET) or {sup 11}C-l-methionine (MET) will indicate tumour extent and response to treatment. The new technologies comprising MR-PET hybrid systems have the advantage of providing comprehensive answers by a one-stop-job of 40-50 min. The combined approach provides data of different modalities using the same iso-centre, resulting in optimal spatial and temporal realignment. All images are acquired exactly under the same physiological conditions. We describe the imaging protocol in detail and provide patient examples for the different imaging modalities such as FET-PET, standard structural imaging (T1-weighted, T2-weighted, T1-weighted contrast agent enhanced), DTI, MRSI and fMRI. (orig.)

  18. An improved Monte Carlo (MC) dose simulation for charged particle cancer therapy

    Energy Technology Data Exchange (ETDEWEB)

    Ying, C. K. [Advanced Medical and Dental Institute, AMDI, Universiti Sains Malaysia, Penang, Malaysia and School of Medical Sciences, Universiti Sains Malaysia, Kota Bharu (Malaysia); Kamil, W. A. [Advanced Medical and Dental Institute, AMDI, Universiti Sains Malaysia, Penang, Malaysia and Radiology Department, Hospital USM, Kota Bharu (Malaysia); Shuaib, I. L. [Advanced Medical and Dental Institute, AMDI, Universiti Sains Malaysia, Penang (Malaysia); Matsufuji, Naruhiro [Research Centre of Charged Particle Therapy, National Institute of Radiological Sciences, NIRS, Chiba (Japan)

    2014-02-12

    Heavy-particle therapy such as carbon ion therapy are more popular nowadays because of the nature characteristics of charged particle and almost no side effect to patients. An effective treatment is achieved with high precision of dose calculation, in this research work, Geant4 based Monte Carlo simulation method has been used to calculate the radiation transport and dose distribution. The simulation have the same setting with the treatment room in Heavy Ion Medical Accelerator, HIMAC. The carbon ion beam at the isocentric gantry nozzle for the therapeutic energy of 290 MeV/u was simulated, experimental work was carried out in National Institute of Radiological Sciences, NIRS, Chiba, Japan by using the HIMAC to confirm the accuracy and qualities dose distribution by MC methods. The Geant4 based simulated dose distribution were verified with measurements for Bragg peak and spread out Bragg peak (SOBP) respectively. The verification of results shows that the Bragg peak depth-dose and SOBP distributions in simulation has good agreement with measurements. In overall, the study showed that Geant4 based can be fully applied in the heavy-ion therapy field for simulation, further works need to be carry on to refine and improve the Geant4 MC simulations.

  19. Whole abdominal irradiation by a moving-strip technique for patients with ovarian cancer

    Energy Technology Data Exchange (ETDEWEB)

    Dembo, A.J.; Van Dyk, J.; Japp,B.; Bean, H.A.; Beale, F.A.; Pringle, J.F.; Bush, R.S.

    1979-11-01

    A technique of moving-strip irradiation of the whole abdomen was utilized in a randomized trial for patients with ovarian cancer. Subjects were classified as being in stages IB, II and III and a bilateral salpingo-oophorectomy and hysterectomy had been completed. With regards both to 5-year survival and control of occult upper abdominal metastases, abdominopelvic irradiation using this technique was significantly better than pelvic irradiation alone or followed by chlorambucil therapy. The essential features of the technique used are (1) Therapy began with pelvic irradiation 2250 rad in 10 fractions followed immediately by a downward moving-strip that encompassed the entire abdomen and pelvis. (2) The dose to the moving-strip was 2250 rad in 10 fractions. (3) The superior border was placed above the diaphragm. This was confirmed on a radiograph taken in expiration. (4) No liver shielding was used. (5) Posterior renal shielding was used throughout (5-half value layer (HVL)). (6) The patients were treated while in a prone position; two fields were treated per day, using an isocentric technique. Serious or symptomatic late complications were rare and were amply justified by a survival gain of approximately 30%.

  20. Cone beam CT evaluation of patient set-up accuracy as a QA tool

    DEFF Research Database (Denmark)

    Nielsen, Morten; Bertelsen, Anders; Westberg, Jonas;

    2009-01-01

    and methods. Eighty four cancer patients have been cone beam CT scanned at treatment sessions 1, 2, 3, 10 and 20. Translational and rotational errors are analyzed. Results and conclusions. For the first three treatment sessions the mean translational error in the AP direction is 1 mm; this indicates a small...... error in the calibration of coronal isocentric laser. The observed SD of the systematic error in each direction is 1 mm if a correction is made after the third fraction with an action limit of 4 mm. The SD of the random errors of the patient group is approximately 1 mm in each direction. The rotational...... errors have a vanishing mean and a systematic error of 0.5 1.2 degrees and a random error of 0.40.7 degrees. The uncertainties from the first three treatment sessions (disregarding rotations) lead to a margin of 4 mm from ITV to PTV for Head-and-Neck patients (all directions) and Thorax patients (AP...

  1. Comparison of 3D conformal radiotherapy vs. intensity modulated radiation therapy (IMRT) of a stomach cancer treatment;Comparacion dosimetrica de radioterapia conformal 3D versus radioterapia de intensidad modulada (IMRT) de un tratamiento de cancer de estomago

    Energy Technology Data Exchange (ETDEWEB)

    Bernui de V, Maria Giselle; Cardenas, Augusto; Vargas, Carlos [Hospital Nacional Carlos Alberto Seguin Escobedo (ESSALUD), Arequipa (Peru). Servicio de Radioterapia

    2009-07-01

    The purpose of this work was to compare the dosimetry in 3D Conformal Radiotherapy with Intensity Modulated Radiation Therapy (IMRT) in a treatment of stomach cancer. For this comparison we selected a patient who underwent subtotal gastrectomy and D2 dissection for a T3N3 adenocarcinoma Mx ECIIIB receiving treatment under the scheme Quimio INT 0116 - in adjuvant radiotherapy. In the treatment plan was contouring the Clinical Target Volume (CTV) and the Planning Target Volume (PTV) was generated from the expansion of 1cm of the CTV, the risky organs contouring were: the liver, kidneys and spinal cord, according to the consensus definition of volumes in gastric cancer. The 3D Conformal Radiotherapy planning is carried out using 6 half beams following the Leong Trevol technique; for the IMRT plan was used 8 fields, the delivery technique is step-and-shoot. In both cases the fields were coplanar, isocentric and the energy used was 18 MV. Intensity Modulated Radiation Therapy (IMRT), in this case has proved to be a good treatment alternative to the technique of 3D Conformal Radiotherapy; the dose distributions with IMRT have better coverage of PTV and positions of the hot spots, as well as the kidneys volume that received higher doses to 2000 cGy is lower, but the decrease in dose to the kidneys is at the expense of increased dose in other organs like the liver. (author)

  2. An ion-optical design study of a carbon-ion rotating gantry with a superconducting final bending magnet

    Energy Technology Data Exchange (ETDEWEB)

    Bokor, J., E-mail: jozef.bokor@stuba.sk; Pavlovič, M.

    2016-03-11

    Ion-optical designs of an isocentric ion gantry with a compact curved superconducting final bending magnet are presented. The gantry is designed for transporting carbon-therapy beams with nominal kinetic energy of 400 MeV/u, which corresponds to the penetration range of C{sup 6+} beam in water of about 28 cm. In contrast to other existing designs, we present a “hybrid” beam transport system containing a single superconducting element – the last bending magnet. All other elements are based on conventional warm technology. Ion-optical properties of such a hybrid system are investigated in case of transporting non-symmetric (i.e. different emittance patterns in the horizontal and vertical plane) beams. Different conditions for transporting the non-symmetric beams are analyzed aiming at finding the optimal, i.e. the most compact, gantry version. The final gantry layout is presented including a 2D parallel scanning. The ion-optical and scanning properties of the final gantry design are described, discussed and illustrated by computer simulations performed by WinAGILE.

  3. Total Body Irradiation using VMAT (RapidArc: A Planning Study of a novel treatment delivery method

    Directory of Open Access Journals (Sweden)

    Santam Chakraborty

    2015-01-01

    Full Text Available Purpose: To evaluate the feasibility of using volumetric modulated arc therapy (VMAT using RapidArc to deliver total body irradiation (TBI treatment. Methods: VMAT planning was performed a whole body computed tomography (CT data set using Rapid Arc. The planning target volumes included entire body trimmed to 3 mm below the skin. The organs at risk included the lungs and kidneys. A dose of 12 Gy in 10 fractions was prescribed to the target volume. The VMAT-TBI technique consisted of three isocentres and three overlapping arcs: the head and neck, the chest, and the pelvis. The plans were prescribed to ensure, at a minimum, 95% planning target volume dose coverage with the prescription dose (percentage of volume receiving dose of 12 Gy was 95% and maximum dose of 109.8%. Mean dose to lung was restricted at 8.6Gy. Results: The total body volume in the study was 15469cm3 and the PTV volume was 11322cm3. The mean dose to PTV was 104%. The homogeneity index was 0.09. Sparing of normal tissues with adequate coverage of skeletal bones was shown to be feasible with Rapid Arc. The study demonstrates that VMAT is feasible for TBI treatment. Unlike conventional TBI chest wall boost with electrons was not required. Conclusion: The technique for total body irradiation using RapidArc VMAT was found feasible and is undergoing further studies prior to clinical use.

  4. Stereotactic radiosurgery in the palliative treatment of brain metastases; Radiocirurgia estereotatica no tratamento paliativo das metastases cerebrais

    Energy Technology Data Exchange (ETDEWEB)

    Faria, Sergio L.; Souhami, Luis; Bahary, Jean-Paul; Clark, Brenda; Adamson, Nelson; Podgorsak, Ervin B. [McGill Univ., Montreal, PQ (Canada). Dept. of Oncology; Caron, Jean-Louis; Villemure, Jean-Guy; Olivier, Andre [McGill Univ., Montreal, PQ (Canada). Dept. of Neurosurgery

    1995-09-01

    Between October, 1988 and November, 1993, 57 patients with metastatic brain disease underwent stereotactic radiosurgery at McGill University, canada. Four patients were excluded from this analysis leaving a total of 53 evaluable patients (with 57 lesions). Radiosurgery was performed with the dynamic rotation technique which uses an isocentric, 10 MV, linear accelerator. A median dose of 1,800 c Gy was given in a single session. In 89% of the cases radiosurgery was used after failure to conventional brain radiotherapy. With a median follow-up of 6 months, the response rate was 65% . Treatments were well tolerated and only 4 patients (7%) developed late complications related to the therapy, with one patient requiring a surgical resection of an area of radionecrose. Radiosurgery appears to be and effective and safe treatment for selected patients with metastatic brain disease, recurrent post-conventional radiotherapy. Its value as a single treatment modality for patients with isolated brain metastasis is now being studied in prospective trials. (author). 29 refs., 4 figs., 4 tabs.

  5. Stereotactic radiation in primary brain tumors in children and adolescents.

    Science.gov (United States)

    Benk, V; Clark, B G; Souhami, L; Algan, O; Bahary, J; Podgorsak, E B; Freeman, C R

    1999-08-01

    To evaluate treatment outcome and morbidity of stereotactic external-beam irradiation (SEBI) in pediatric patients, we reviewed 14 children treated with SEBI, using a 10-MV isocentric linear accelerator at McGill University between 1988 and 1994. The median follow-up was 46 months (range 6-82 months). The median age was 14 years. There were 8 low-grade astrocytomas, 3 neuromas and 4 other histologies. Twelve patients received fractionated treatments. The median collimator diameter was 2.5 cm (range 1-5 cm). The median biological effective dose delivered to the entire tumor volume was 57 Gy for astrocytomas and 43 Gy for the other histologies. The overall actuarial survival rate and disease-free survival rate at 5 years were 83 and 62%, respectively. For the patients with low-grade astrocytomas, the 5-year survival and disease-free survival rates were 100 and 60%, respectively. Four children had recurrence at a median of 37 months. Four patients developed treatment-related complications: 1 had edema alone, 2 had necrosis and 1 had edema associated with necrosis. Neither the physical nor radiobiological parameters were predictive of the treatment outcome or the treatment complications. Stereotactic irradiation is a valid option for progressive nonresectable tumors in children.

  6. The physical characteristics of the 15 MV Varian Clinac 2100C unflattened beam

    Science.gov (United States)

    Najem, M. A.; Spyrou, N. M.; Podolyák, Z.; Abolaban, F. A.

    2014-02-01

    A 15 MV photon beam of a Varian Clinac 2100C medical linear accelerator operating with and without a flattening filter was simulated using the Monte Carlo code 'FLUKA' in order to calculate differences in their dosimetric properties. These include: the dose rate, the percentage depth dose on the central axis, the beam profile, the out-of-field dose, the surface dose on a 40×40×40 cm3 water phantom and the neutron contamination. The results obtained showed that the unflattened beam has a dose rate 4.86 times higher than the flattened one. The average out-of-field dose from the edge of the field to the edge of the phantom was reduced by 44%, the neutron fluence at the isocentre was reduced by 77% and the surface neutron dose-equivalent was reduced from 2.11±0.05 to 0.40±0.01 mSv(n) Gy-1(X) after normalising both beams to give the same dose at dmax (the depth of maximum dose). However, the photon surface dose of the unflattened beam increased by 13%. From this information, it can be concluded that the unflattened beam can lead to better treatment outcome and may reduce the beam-on time which may be required for specific cases.

  7. "Riesenrad" Ion Gantry for Hadron Therapy, 3

    CERN Document Server

    Benedikt, Michael; Holy, P; Pullia, M

    1999-01-01

    When using accelerator beams for cancer therapy, the three-dimensional freedom afforded by a gantry helps the treatment planner to spread out surface doses, avoid directions that intercept vital organs and irradiate a volume that is conformal with the tumour. The general preference is for an iso-centric gantry turning 360° in the vertical plane around the patient bed with sufficient space to be able to orientate the patient through 360° in the horizontal plane. For hadrontherapy, gantries are impressive structures of the order of 10 m in diameter and 100 tons in weight and to date only proton gantries have been demonstrated to operate satisfactorily. The increased magnetic rigidity of say carbon ions will make ion gantries more difficult and costly to build. For this reason, exo-centric gantries and, in particular the so-called 'Riesenrad' gantry with a single 90° bending magnet, merit further attention. The power consumption is reduced and the heavy magnets with their counterbalance weight are reduced and...

  8. An improved Monte Carlo (MC) dose simulation for charged particle cancer therapy

    Science.gov (United States)

    Ying, C. K.; Kamil, W. A.; Shuaib, I. L.; Matsufuji, Naruhiro

    2014-02-01

    Heavy-particle therapy such as carbon ion therapy are more popular nowadays because of the nature characteristics of charged particle and almost no side effect to patients. An effective treatment is achieved with high precision of dose calculation, in this research work, Geant4 based Monte Carlo simulation method has been used to calculate the radiation transport and dose distribution. The simulation have the same setting with the treatment room in Heavy Ion Medical Accelerator, HIMAC. The carbon ion beam at the isocentric gantry nozzle for the therapeutic energy of 290 MeV/u was simulated, experimental work was carried out in National Institute of Radiological Sciences, NIRS, Chiba, Japan by using the HIMAC to confirm the accuracy and qualities dose distribution by MC methods. The Geant4 based simulated dose distribution were verified with measurements for Bragg peak and spread out Bragg peak (SOBP) respectively. The verification of results shows that the Bragg peak depth-dose and SOBP distributions in simulation has good agreement with measurements. In overall, the study showed that Geant4 based can be fully applied in the heavy-ion therapy field for simulation, further works need to be carry on to refine and improve the Geant4 MC simulations.

  9. Comparative analysis of dose-volume histograms between 3D conformal and conventional non-conformal radiotherapy planning for prostate cancer; Analise comparativa dos histogramas de dose e volume entre planejamentos tridimensionais conformados e convencionais nao conformados na radioterapia do cancer de prostata

    Energy Technology Data Exchange (ETDEWEB)

    Feitosa, Silvia Moreira; Giordani, Adelmo Jose; Dias, Rodrigo Sousa; Segreto, Helena Regina Comodo; Segreto, Roberto Araujo [Universidade Federal de Sao Paulo (UNIFESP-EPM), Sao Paulo, SP (Brazil)], e-mail: silviamfeitosa@yahoo.com.br

    2009-03-15

    Objective: The present study was aimed at comparing conformal and non-conformal radiotherapy plans designed for patients with prostate cancer, by analyzing radiation doses in target volumes and organs at risk. Materials and methods: Radiotherapy plans for 40 patients with prostate cancer were analyzed. Conformal, conformal isocentric and non-conformal plans utilizing the source-surface distance were simulated for each of the patients for comparison of radiation dose in target volumes and organs at risk. For comparison purposes, dose-volume histograms for target volumes and organs at risk were analyzed. Results: Median doses were significantly lower in the conformal planning, with 25%, 40% and 60% volumes in the rectum and 30% and 60% in the bladder. The median doses were significantly lower in the conformal planning analyzing the right and left coxofemoral joints. Maximum, mean and median doses in the clinical target volume and in the planned target volume were significantly higher in the conformal planning. Conclusion: The present study has demonstrated that the conformal radiotherapy planning for prostate cancer allows the delivery of higher doses to the target volume and lower doses to adjacent healthy tissues. (author)

  10. Accuracy in the reproducibility of daily patients' setup in 3D conformal radiotherapy for prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Giordani, Adelmo Jose; Dias, Rodrigo Souza; Segreto, Roberto Araujo, E-mail: adelmogiordani@ig.com.b [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Unidade de Radioterapia; Segreto, Helena Regina Comodo [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Dept. de Oncologia Clinica e Experimental

    2010-07-15

    Objective: to evaluate the reproducibility of daily patients' setup in 3D conformal radiotherapy for prostate cancer. Materials and methods: the present study evaluated a total of 960 radiological images (anterior and lateral views) of 120 patients submitted to conformal radiotherapy for prostate cancer with the isocentric technique. A 6 MV particle accelerator was utilized in the process. A specific protocol for prostate radiotherapy planning and treatment was applied, with the patients placed in supine position, hands on the chest and legs placed on and appropriate support. Daily, the patients were positioned according to previously made skin markings in alignment with the in-room laser. The portal images were compared with digitally reconstructed radiographs (DRR) in the Eclipse treatment planning system based on the tomographic images. Radiography was performed at the first day, and weekly afterwards until the treatment was completed. Results: the following average position shifts were observed: 1.99 +- 1.25 mm craniocaudally, 1.37 +- 0.84 mm laterally, and 1.94 +- 1.10 mm anteroposteriorly. Conclusion: the use of specific protocols for patients' setup is feasible in the clinical practice, allowing appropriate reproducibility and quick correction of possible errors in conformal radiotherapy for prostate cancer. (author)

  11. Development of a superconducting rotating-gantry for heavy-ion therapy

    Energy Technology Data Exchange (ETDEWEB)

    Iwata, Y., E-mail: y_iwata@nirs.go.jp [Department of Accelerator and Medical Physics, National Institute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage, Chiba 263-8555 (Japan); Noda, K.; Murakami, T.; Shirai, T.; Furukawa, T.; Fujita, T.; Mori, S.; Mizushima, K.; Shouda, K. [Department of Accelerator and Medical Physics, National Institute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage, Chiba 263-8555 (Japan); Fujimoto, T. [Accelerator Engineering Corporation (AEC), 3-8-5 Konakadai, Inage, Chiba 263-0043 (Japan); Ogitsu, T. [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Obana, T. [National Institute for Fusion Science (NIFS), 322-6 Oroshi-cho, Toki-city509-5292 (Japan); Amemiya, N. [Faculty of Engineering, Kyoto University, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto 615-8530 (Japan); Orikasa, T.; Takami, S.; Takayama, S. [Toshiba Corporation, 1-1-1 Shibaura, Minato-ku, Tokyo 105-8001 (Japan)

    2013-12-15

    An isocentric superconducting rotating-gantry for heavy-ion therapy is being developed. This rotating gantry can transport heavy ions having 430 MeV/u to an isocenter with irradiation angles of over ±180°, and is further capable of performing fast raster-scanning irradiation. For the magnets, combined-function superconducting-magnets are to be employed. All of the superconducting magnets have been designed, and their magnetic-field distributions were calculated by using a 3D electromagnetic-field solver. With the calculated magnetic-fields, beam-tracking simulations were performed to evaluate the field quality of the superconducting magnets. Beam profiles as well as phase-space distributions at the isocenter, as calculated by simulations, agreed well with those of linear beam-optics calculations, proving validity of the final design for the magnets. Three superconducting magnets were manufactured, and are being tested. In this paper, results of tracking simulations as well as test results for the superconducting magnets are presented.

  12. Design and evaluation of a grid reciprocation scheme for use in digital breast tomosynthesis

    Science.gov (United States)

    Patel, Tushita; Sporkin, Helen; Peppard, Heather; Williams, Mark B.

    2016-03-01

    This work describes a methodology for efficient removal of scatter radiation during digital breast tomosynthesis (DBT). The goal of this approach is to enable grid image obscuration without a large increase in radiation dose by minimizing misalignment of the grid focal point (GFP) and x-ray focal spot (XFS) during grid reciprocation. Hardware for the motion scheme was built and tested on the dual modality breast tomosynthesis (DMT) scanner, which combines DBT and molecular breast tomosynthesis (MBT) on a single gantry. The DMT scanner uses fully isocentric rotation of tube and x-ray detector for maintaining a fixed tube-detector alignment during DBT imaging. A cellular focused copper prototype grid with 80 cm focal length, 3.85 mm height, 0.1 mm thick lamellae, and 1.1 mm hole pitch was tested. Primary transmission of the grid at 28 kV tube voltage was on average 74% with the grid stationary and aligned for maximum transmission. It fell to 72% during grid reciprocation by the proposed method. Residual grid line artifacts (GLAs) in projection views and reconstructed DBT images are characterized and methods for reducing the visibility of GLAs in the reconstructed volume through projection image flat-field correction and spatial frequency-based filtering of the DBT slices are described and evaluated. The software correction methods reduce the visibility of these artifacts in the reconstructed volume, making them imperceptible both in the reconstructed DBT images and their Fourier transforms.

  13. Engineering design and study of the beam position accuracy in the "Riesenrad" ion gantry

    CERN Document Server

    Reimoser, S A

    2001-01-01

    Beams of carbon ions are particularly well suited for radiotherapy. Their physical properties allow the 3D-conformal tumour irradiation with a sub-millimetre precision, provided that the beam is delivered by a rotating gantry equipped with a pencil-beam scanning system. However, the expected size and weight of such a carbon-ion gantry together with the requirement to direct the beam to the patient with an extreme position accuracy has so far prevented its realisation and stimulated the search for alternative solutions. One of them, the "Riesenrad" ion gantry, is introduced in the present paper. In contrast to conventional isocentric gantries, the main bending magnet of the Riesenrad is placed on the axis of gantry rotation, hence minimising the moment of inertia of the mobile structure and maximising its rigidity. The treatment cabin is smoothly moved towards the desired treatment position by a system that is mechanically de-coupled from the gantry. The engineering design as well as some aspects of the beam t...

  14. A new tilt on pelvic radiographs: a pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Richards, P.J. [North Staffordshire Royal Infirmary, Department of Radiology, Stoke-on-Trent, Staffordshire (United Kingdom); Pattison, J.M. [University Hospital of North Staffordshire, Department of Radiology, Stoke on Trent (United Kingdom); Belcher, J. [Keele University, Department of Mathematics, Keele, Staffordshire (United Kingdom); DeCann, R.W. [IMECS, Department of Radiology, Market Drayton, Shropshire (United Kingdom); Anderson, Suzanne [University of Melbourne, Department of Radiology, Melbourne (Australia); Wynn-Jones, C. [University Hospital of North Staffordshire, Department of Orthopaedic Surgery, Stoke on Trent (United Kingdom)

    2009-02-15

    The aim of this study was to evaluate pelvic tilt on commonly performed measurements on radiography in primary protrusio acetabuli and developmental dysplasia of the hip. A dry assembled pelvis and spine skeleton was positioned in an isocentric skull unit and films exposed with increasing degrees of angulation of pelvic tilt. The films were then read by two independent readers for seven different measurements used to evaluate the hips and acetabular: acetabular line to ilioischial line, teardrop appearance, intercristal/intertuberous ratio, co-ordinates of femoral head, centre edge angle, acetabular depth/width ratio and acetabular angle. There was so much variation in the protrusio results that no formal recommendation of any standard radiographic test can be given. Only the inter tuberous distance is not effected by pelvic tilt. The acetabular angles for developmental dysplasia of the hip showed the most potential with pelvic tilt below 15 . As pelvic tilt increases, measurements used in protusio become unreliable, and computed tomography/magnetic resonance imaging are probably going to be more accurate as one can directly visualise pelvic intrusion. We recommend a lateral view to assess the degree of pelvic tilt in patients with protrusion to ensure these measurements are valid. (orig.)

  15. Application of multileaf collimator in breast cancer radiation techniques

    Science.gov (United States)

    Janiszewska, Marzena; Dupla, Dorota; Nowakowski, Grzegorz

    2004-07-01

    Modern radiation therapy tools allow a precise delivery of a high dose to a target area (so-called planning target volume -- PTV) and spare, at the same time, critical organs in the vicinity of cancerous lesions. One of the tools of conformal therapy is a multi-leaf collimator, which provides the opportunity to optimally adjust the therapeutic field to the tumor area. More difficult areas for radiation therapy include: mamma, after BCT, and chest after mammectomy with regional lymph nodes. The objective of the study is to present technical and physical aspects of breast carcinoma irradiation when applying a multi-leaf collimator. The following techniques were applied: (a) the isocentric technique of tangent fields (from two to four) for the mamma after BCT; (b) the method of a common isocenter, for the areas of mamma and for regional lymph nodes; (c) the technique of complementary photon + electron fields, for the area of chest after mammectomy and lymph nodes. The presented techniques were implemented as standard procedures in the preparation of breast carcinoma radiation treatment in the Lower Silesian Oncology Center.

  16. Development and Clinical Implementation of a Universal Bolus to Maintain Spot Size During Delivery of Base of Skull Pencil Beam Scanning Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Both, Stefan, E-mail: Stefan.Both@uphs.upenn.edu [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Shen, Jiajian [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Department of Radiation Oncology, Mayo Clinic, Phoenix, Arizona (United States); Kirk, Maura; Lin, Liyong; Tang, Shikui; Alonso-Basanta, Michelle; Lustig, Robert; Lin, Haibo; Deville, Curtiland; Hill-Kayser, Christine; Tochner, Zelig; McDonough, James [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania (United States)

    2014-09-01

    Purpose: To report on a universal bolus (UB) designed to replace the range shifter (RS); the UB allows the treatment of shallow tumors while keeping the pencil beam scanning (PBS) spot size small. Methods and Materials: Ten patients with brain cancers treated from 2010 to 2011 were planned using the PBS technique with bolus and the RS. In-air spot sizes of the pencil beam were measured and compared for 4 conditions (open field, with RS, and with UB at 2- and 8-cm air gap) in isocentric geometry. The UB was applied in our clinic to treat brain tumors, and the plans with UB were compared with the plans with RS. Results: A UB of 5.5 cm water equivalent thickness was found to meet the needs of the majority of patients. By using the UB, the PBS spot sizes are similar with the open beam (P>.1). The heterogeneity index was found to be approximately 10% lower for the UB plans than for the RS plans. The coverage for plans with UB is more conformal than for plans with RS; the largest increase in sparing is usually for peripheral organs at risk. Conclusions: The integrity of the physical properties of the PBS beam can be maintained using a UB that allows for highly conformal PBS treatment design, even in a simple geometry of the fixed beam line when noncoplanar beams are used.

  17. Geant4 studies of the CNAO facility system for hadrontherapy treatment of uveal melanomas

    Science.gov (United States)

    Rimoldi, A.; Piersimoni, P.; Pirola, M.; Riccardi, C.

    2014-06-01

    The Italian National Centre of Hadrontherapy for Cancer Treatment (CNAO -Centro Nazionale di Adroterapia Oncologica) in Pavia, Italy, has started the treatment of selected cancers with the first patients in late 2011. In the coming months at CNAO plans are to activate a new dedicated treatment line for irradiation of uveal melanomas using the available active beam scan. The beam characteristics and the experimental setup should be tuned in order to reach the necessary precision required for such treatments. Collaboration between CNAO foundation, University of Pavia and INFN has started in 2011 to study the feasibility of these specialised treatments by implementing a MC simulation of the transport beam line and comparing the obtained simulation results with measurements at CNAO. The goal is to optimise an eye-dedicated transport beam line and to find the best conditions for ocular melanoma irradiations. This paper describes the Geant4 toolkit simulation of the CNAO setup as well as a modelised human eye with a tumour inside. The Geant4 application could be also used to test possible treatment planning systems. Simulation results illustrate the possibility to adapt the CNAO standard transport beam line by optimising the position of the isocentre and the addition of some passive elements to better shape the beam for this dedicated study.

  18. Shielding evaluation and acceptance testing of a prefabricated, modular, temporary radiation therapy treatment facility.

    Science.gov (United States)

    Ezzell, Gary A

    2004-01-01

    We have recently commissioned a temporary radiation therapy facility that is novel in two aspects: it was constructed using modular components, and the LINAC was installed in one of the modular sections before it was lifted into position. Additional steel and granular fill was added to the modular sections on-site during construction. The building will be disassembled and removed when no longer needed. This paper describes the radiation shielding specifications and survey of the facility, as well as the ramifications for acceptance testing occasioned by the novel installation procedure. The LINAC is a Varian 21EX operating at 6 MV and 18 MV. The radiation levels outside the vault satisfied the design criteria, and no anomalous leakage was detected along the joints of the modular structure. At 18 MV and 600 monitor units (MU) per minute, the radiation level outside the primary barrier walls was 8.5 micro Sv/h of photons; there were no detectable neutrons. Outside the direct-shielded door, the levels were 0.4 micro Sv/h of photons and 3.0 micro Sv/h of neutrons. The isocentricity of the accelerator met the acceptance criteria and was not affected by its preinstallation into an integrated baseframe and subsequent transport to the building site.

  19. Initial application of digital tomosynthesis to improve brachytherapy treatment planning

    Science.gov (United States)

    Baydush, Alan H.; Mirzaei McKee, Mahta; King, June; Godfrey, Devon J.

    2007-03-01

    We present preliminary investigations that examine the feasibility of incorporating volumetric images generated using digital tomosynthesis into brachytherapy treatment planning. The Integrated Brachytherapy Unit (IBU) at our facility consists of an L-arm, C-arm isocentric motion system with an x-ray tube and fluoroscopic imager attached. Clinically, this unit is used to generate oblique, anterior-posterior, and lateral images for simple treatment planning and dose prescriptions. Oncologists would strongly prefer to have volumetric data to better determine three dimensional dose distributions (dose-volume histograms) to the target area and organs at risk. Moving the patient back and forth to CT causes undo stress on the patient, allows extensive motion of organs and treatment applicators, and adds additional time to patient treatment. We propose to use the IBU imaging system with digital tomosynthesis to generate volumetric patient data, which can be used for improving treatment planning and overall reducing treatment time. Initial image data sets will be acquired over a limited arc of a human-like phantom composed of real bones and tissue equivalent material. A brachytherapy applicator will be incorporated into one of the phantoms for visualization purposes. Digital tomosynthesis will be used to generate a volumetric image of this phantom setup. This volumetric image set will be visually inspected to determine the feasibility of future incorporation of these types of images into brachytherapy treatment planning. We conclude that initial images using the tomosynthesis reconstruction technique show much promise and bode well for future work.

  20. On the question of 3D seed reconstruction in prostate brachytherapy: the determination of x-ray source and film locations

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Mutian [Radiation Safety Office, Columbia University Medical Center, 722 West 168th Street, New York, NY 10032 (United States); Zaider, Marco [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021 (United States); Worman, Michael [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021 (United States); Cohen, Gilad [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021 (United States)

    2004-10-07

    Inaccuracy in seed placement during permanent prostate implants may lead to significant dosimetric deviations from the intended plan. In two recent publications (Todor et al 2002 Phys. Med. Biol. 47 2031-48, Todor et al 2003 Phys. Med. Biol. 48 1153-71), methodology was described for identifying intraoperatively the positions of seeds already implanted, thus allowing re-optimization of the treatment plan and correcting for such seed misplacement. Seed reconstruction is performed using fluoroscopic images and an important (and non-trivial) component of this approach is the ability to accurately determine the position of the gantry relative to the treatment volume. We describe the methodology for acquiring this information, based on the known geometry of six markers attached to the ultrasound probe. This method does not require the C-arm unit to be isocentric and films can be taken with the gantry set at any arbitrary position. This is significant because the patient positioning on the operating table (in the lithotomy position) restricts the range of angles at which films can be taken to a quite narrow (typically {+-}10{sup 0}) interval and, as a general rule, the closer the angles the larger the uncertainty in the seed location reconstruction along the direction from the x-ray source to the film. (note)

  1. Short communication: assessment of environmental disturbances to the static magnetic field in magnetic resonance installations.

    Science.gov (United States)

    Schmidt, M A

    2006-05-01

    The static magnetic field of MRI scanners can be affected by environmental factors. Magnetic resonance spectroscopy and functional imaging with single-shot echo-planar imaging (EPI) are particularly vulnerable to the movement of lifts, vehicles, trains and other large metallic masses in the vicinity. This work investigates the sensitivity of two different imaging techniques to assess disturbances of the static magnetic field: (i) phase changes in gradient-echo images of a uniform test object; and (ii) image displacement along the phase encoding direction in single-shot EPI images. For the latter a hexane sample was used, and the separation between CH2 and CH3 signals was taken as a reference. Both techniques were evaluated in a site known to be free of any significant environmental disturbances and validated by inducing a magnetic field disturbance. Both techniques provide valuable information in acceptance tests, allowing MRI users to evaluate and manage the environmental conditions surrounding a scanner. The single-shot EPI technique was found to be highly sensitive, being expected to detect magnetic field fluctuations down to 0.005 parts per million (ppm). The phase images method was found to be less sensitive (0.02 ppm) but is more easily available. The single-shot EPI technique was used in acceptance tests and environmental disturbances to the magnetic field of the order of 0.04 ppm were measured at the isocentre on two separate occasions.

  2. An ion-optical design study of a carbon-ion rotating gantry with a superconducting final bending magnet

    Science.gov (United States)

    Bokor, J.; Pavlovič, M.

    2016-03-01

    Ion-optical designs of an isocentric ion gantry with a compact curved superconducting final bending magnet are presented. The gantry is designed for transporting carbon-therapy beams with nominal kinetic energy of 400 MeV/u, which corresponds to the penetration range of C6+ beam in water of about 28 cm. In contrast to other existing designs, we present a ;hybrid; beam transport system containing a single superconducting element - the last bending magnet. All other elements are based on conventional warm technology. Ion-optical properties of such a hybrid system are investigated in case of transporting non-symmetric (i.e. different emittance patterns in the horizontal and vertical plane) beams. Different conditions for transporting the non-symmetric beams are analyzed aiming at finding the optimal, i.e. the most compact, gantry version. The final gantry layout is presented including a 2D parallel scanning. The ion-optical and scanning properties of the final gantry design are described, discussed and illustrated by computer simulations performed by WinAGILE.

  3. Optimization of megavoltage CT scan registration settings for brain cancer treatments on tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Woodford, Curtis; Yartsev, Slav; Van Dyk, Jake [London Regional Cancer Program, London Health Sciences Centre, 790 Commissioners Road East, London, Ontario (Canada)

    2007-04-21

    This study aims to determine the settings that provide the optimal clinical accuracy and consistency for the registration of megavoltage CT (MVCT) with planning kilovoltage CT image sets on the Hi-ART tomotherapy system. The systematic offset between the MVCT and the planning kVCT was determined by registration of multiple MVCT scans of a head phantom aligned with the planning isocentre. Residual error vector lengths and components were used to quantify the alignment quality for the phantom shifted by 5 mm in different directions obtained by all 27 possible combinations of MVCT inter-slice spacing, registration techniques and resolution. MVCT scans with normal slices are superior to coarse slices for registration of shifts in the superior-inferior, lateral and anterior-posterior directions. Decreasing the scan length has no detrimental effect on registration accuracy as long as the scan lengths are larger than 24 mm. In the case of bone technique and fine resolution, normal and fine MVCT scan slice spacing options give similar accuracy, so normal mode is preferable due to shorter procedure and less delivered dose required for patient set-up. A superior-inferior field length of 24-30 mm, normal slice spacing, bone technique, and fine resolution is the optimum set of registration settings for MVCT scans of a Rando head phantom acquired with the Hi-ART tomotherapy system, provided the registration shifts are less than 5 mm. (note)

  4. Commissioning Siemens Virtual Wedges in the Oncentra MasterPlan treatment planning system using Gafchromic EBT film.

    Science.gov (United States)

    Ferretti, A; Simonato, F; Zandonà, R; Reccanello, S; Fabbris, R

    2010-12-01

    Virtual Wedges were introduced in Siemens LINACs to improve the treatment workflow. The aim of the present work is the validation of dose calculation by MasterPlan-Oncentra treatment planning system for virtual wedged beams. The Oncor Siemens accelerator installed in the authors' department produces 6 and 15 MV photon beams. At first, the consistency of VW LINAC production was tested and the EBT film measuring method was verified. This method is based on the scanner uniformity correction and absolute dose calibration as reported in literature. Then, the measured and calculated wedge factors and beam profiles are compared. For 15 degrees, 30 degrees, 45 degrees, and 60 degrees wedge angles, the wedge factors for different field sizes were measured by an ionization chamber and the dose profiles were acquired by Gafchromic EBT film. Both types of measurements were collected in isocentric condition. The comparison between measured and calculated VW factors shows discrepancies that increase with field size and angle. The OTP Enhanced algorithm produces better agreement with measurements than the Classic one, with improvement overall visible for large angles. The agreement between measured and planned beam profiles is within limits reported by the ESTRO Booklet No. 7 in terms of confidence limits. The MasterPlan-Oncentra treatment planning system determines wedge factors and VW profiles within the requested accuracy in the majority of treatment conditions. For big field dimensions and wedge angle, wedge factor accordance was worse, but it may be increased with an improvement of the LINAC dosimetric board calibration.

  5. The efficiency of orthotic interventions on energy consumption in paraplegic patients: a literature review.

    Science.gov (United States)

    Arazpour, M; Samadian, M; Bahramizadeh, M; Joghtaei, M; Maleki, M; Ahmadi Bani, M; Hutchins, S W

    2015-01-20

    Study design:This is a systematic literature review.Objectives:Different types of orthoses have been developed to enable and facilitate ambulation in individuals with paraplegia. However, their effect on energy consumption while ambulating is not clear. The objective of this review was to compare the energy expenditure required to walk with these devices.Methods:Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method, and based on selected keywords and their composition according to the Population Intervention Comparison Outcome (PICO) method, a search was performed in Science Direct, Google Scholar, Scopus, Web of Knowledge and PubMed databases. The searches were restricted to papers published in the English language and were conducted during February 2014; the last access to the database was on 25 February 2014. A total of 24 articles were chosen for final evaluation.Results:Hybrid orthoses reduce energy consumption compared with mechanical orthoses when used for walking by paraplegic patients. The isocentric reciprocating gait orthosis has been shown to be more effective than other reciprocating orthoses in reducing energy consumption. Energy consumption when walking with powered orthoses (PO) and hybrid orthoses was also reduced compared with when walking with conventional orthoses.Conclusions:The hybrid orthoses and PO could be effective alternatives in rehabilitation for spinal cord injury patients to help improve the energy consumption.Spinal Cord advance online publication, 20 January 2015; doi:10.1038/sc.2014.227.

  6. Radiotherapy for treatment of bursitis. Indication, technique, own results, literature survey; Strahlentherapie bei der Periarthropathia humeroscapularis (PHS). Indikation, Technik, eigene Ergebnisse, Literaturuebersicht

    Energy Technology Data Exchange (ETDEWEB)

    Heyd, R. [Staedtische Kliniken Offenbach am Main (Germany). Strahlenklinik]|[Frankfurt Univ. (Germany). Klinik fuer Strahlentherapie und Onkologie; Schopohl, B.; Boettcher, H.D. [Frankfurt Univ. (Germany). Klinik fuer Strahlentherapie und Onkologie

    1998-12-31

    Our own experience covers 41 primarily chronic cases. The patients have been irradiated with a telecobalt device with isocentric opposing fields, receiving 4x1.0 Gy within two weeks; 15 patients (36.6%) received a second radiation treatment (8 Gy), and one patient (2.4%) a third (12 Gy). After a follow-up period of 44 months on the average, the results were: Complete remittence of pain in 44%, abatement of pain in 44%, and no effect in 12%. Improvement of shoulder joint motility was achieved in 78%. The rate of recidivation was as low as 3%. A statistical evaluation of data acquired revealed that the prognosis is worst in case of a long period of pain preceding commencement of radiotherapy, combined with intensive prior therapy. (orig./CB) [Deutsch] In einer eigenen Untersuchung wurden 41 ueberwiegend chronische Faelle mit 4x1,0 Gy in 2 Wochen an einem Telekobaltgeraet mit isozentrischen Gegenfeldern behandelt, 15 (36,6%) erhielten eine 2. Bestrahlungsserie (8 Gy), ein Fall (2,4%) eine Dritte (12 Gy). Nach einem Nachbeobachtungszeitraum von median 44 Monaten fand sich bei 44% eine komplette Schmerzremission, bei 44% eine Linderung und 12% waren ohne einen Einfluss der Behandlung. Eine Verbesserung der Motilitaet des Schultergelenkes wurde bei 78% erreicht. Die Rezidivrate lag bei nur 3%. Nach statistischer Bearbeitung der Daten erwies sich die Kombination einer langen Beschwerdedauer vor Einleitung der Radiotherapie und intensiver Vortherapie als prognostisch unguenstiger (p=0,02). (orig.)

  7. Photon science 2008. Highlights and HASYLAB annual report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    The following topics are dealt with: A femtosecond X-ray/optical cross-correlator, ultrafast movies of nanoscale dynamics, massively parallel X-ray holography, clusters in super intense FLASH pulses, a chemical driven insulator-metal transition, tough silk, insight into the reactivity, the many faces of molecular assemblies in electronic devices, cooperative or self-centred electrons, visualizing a lost painting by Vincent van Gogh, metal contaminations in small water fleas, small-angle X-ray scattering as complement of crystallography, mapping the protein world, how metallic iron eats its own native oxide, hard X-ray diffraction imaging, the centre for free-electron laser science CFEL, the Hamburg EMBL unit, the Max-Planck unit for structural molecular biology, the GKSS Research Centre Geesthacht, the GFZ Helmholtz Centre Potsdam, the University of Hamburg on the DESY site, the light sources DORIS III, FLASH, PETRA III, and the European XFEL project, beamline enhancements and photon diagnostics at FLASH, undulator development for the European XFEL, special X-ray monochromators for PETRA III, high-power photon slits and shutters, the generation of brilliant beams, undulator demagnetization in LINAC based FELs, the control of experiments, advanced detection. (HSI)

  8. Beam extraction dynamics at the space-charge-limit of the high brightness E-XFEL electron source at DESY-PITZ

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ye; Gjonaj, Erion; Weiland, Thomas [TEMF, Technische Universitaet Darmstadt, Schlossgartenstrasse 8, 64289 Darmstadt (Germany)

    2015-07-01

    The physics of the photoemission, as one of the key issues for successful operation of linac based free-electron lasers like the European X-ray Free Electron Laser (E-XFEL) and the Free-electron Laser in Hamburg (FLASH), is playing an increasingly important role in the high brightness DESY-PITZ electron source. We study photoemission physics and discuss full three-dimensional numerical modeling of the electron bunch emission. The beam extraction dynamics at the photocathode has been investigated through the 3D fully electromagnetic (EM) Particle-in-Cell (PIC) solver of CST Particle Studio under the assumption of the photoemission source operating at or close to its space charge limit. PIC simulation results have shown good agreements with measurements on total emitted bunch charge for distinct experimental parameters. Further comparisons showed a general failure for the conventional Poisson solver based tracking algorithm to correctly predict the beam dynamics at the space charge limit. It is furthermore found, that fully EM PIC simulations are also consistent with a simple emission model based on the multidimensional Child-Langmuir law.

  9. Cryostat for Testing HIE-Isolde Superconducting RF Cavities

    CERN Document Server

    Capatina, O; Cuccuru, G; Pasini, M; Renaglia, T; Therasse, M; Vullierme, B

    2011-01-01

    The High Intensity and Energy ISOLDE (HIE-ISOLDE) project is a major upgrade of the existing ISOLDE and REX-ISOLDE facilities at CERN [1], with the objective of increasing the energy and intensity of the delivered radioactive ion beams (RIB). This project aims to fill the request for a more energetic post-accelerated beam by means of a new superconducting (SC) linac based on Quarter Wave Resonators (QWR). A research and development (R&D) programme looking at all the different aspects of the SC linac started in 2008 and continued throughout 2010. The R&D effort has particularly focused on the development of the high β cavities (β = 10.3%) for which the Nb sputtered on Cu substrate technology has been adopted. Two prototype cavities were manufactured and are undergoing RF cold tests. The pre-series cavity manufacturing is under way using 3D forged Cu billets. A single vacuum cryostat was designed and built to test these cavities at liquid helium temperatures. This paper details the main design concep...

  10. Dechirper Wakefields for Short Bunches

    CERN Document Server

    Bane, Karl

    2016-01-01

    In previous work [1] general expressions, valid for arbitrary bunch lengths, were derived for the wakefields of corrugated structures with flat geometry, such as is used in the RadiaBeam/LCLS dechirper. However, the bunch at the end of linac-based X-ray FELs--like the LCLS--is extremely short, and for short bunches the wakes can be considerably simplified. In this work, we first derive analytical approximations to the short-range wakes. These are generalized wakes, in the sense that their validity is not limited to a small neighborhood of the symmetry axis, but rather extends to arbitrary transverse offsets of driving and test particles. The validity of these short-bunch wakes holds not only for the corrugated structure, but rather for any flat structure whose beam-cavity interaction can be described by a surface impedance. We use these wakes to obtain, for a short bunch passing through a dechirper: estimates of the energy loss as function of gap, the transverse kick as function of beam offset, the slice ener...

  11. Wakefields of a Beam near a Single Plate in a Flat Dechirper

    Energy Technology Data Exchange (ETDEWEB)

    Bane, Karl; Stupakov, Gennady; /SLAC; Zagorodnov, Igor; /DESY

    2016-11-29

    At linac-based, X-ray free electron lasers (FELs), there is interest in streaking the beam by inducing the transverse wakes in a flat dechirper, by passing the beam near to one of its two jaws. For LCLS-II - as has already been done for LCLS-I - this way of using the dechirper will e.g. facilitate two-color and fresh slice schemes of running the FEL. With the beam a distance from the near wall of say b ~ 0.25 mm and from the far wall by ≳ 5 mm, the second wall will no longer affect the results. The physics will be quite different from the two plate case: with two plates the impedance has a resonance spike whose frequency depends on the plate separation 2a; in the single plate case this parameter no longer exists. Formulas for the longitudinal, dipole, and quadrupole wakes for a beam off-axis between two dechirper plates, valid for the range of bunch lengths of interest in an X-ray FEL, are given in reference 3. By taking the proper limit, we can obtain the corresponding wakes for a beam close to one dechirper plate and far from the other. This is the task we perform in this note.

  12. CONDITIONS FOR CSR MICROBUNCHING GAIN SUPPRESSION

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Cheng Ying [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Douglas, David R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Li, Rui [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Tennant, Christopher D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); di Mitri, Simone [Elettra–Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy

    2016-05-01

    The coherent synchrotron radiation (CSR) of a high brightness electron beam traversing a series of dipoles, such as transport arcs, may result in phase space degradation. On one hand, the CSR can perturb electron transverse motion in dispersive regions along the beamline, causing emittance growth. On the other hand, the CSR effect on the longitudinal beam dynamics could result in microbunching gain enhancement. For transport arcs, several schemes have been proposed* to suppress the CSR-induced emittance growth. Similarly, several scenarios have been introduced** to suppress CSR-induced microbunching gain, which however mostly aim for linac-based machines. In this paper we try to provide sufficient conditions for suppression of CSR-induced microbunching gain along a transport arc, analogous to*. Several example lattices are presented, with the relevant microbunching analyses carried out by our semi-analytical Vlasov solver***. The simulation results show that lattices satisfying the proposed conditions indeed have microbunching gain suppressed. We expect this analysis can shed light on lattice design approach that could suppress the CSR-induced microbunching gain.

  13. Potential diagnostics for the next-generation light sources

    CERN Document Server

    Lumpkin, Alex H

    1999-01-01

    There is continued interest in developing a diffraction-limited soft or hard X-ray source. Candidate paths include the storage-ring-based free-electron laser (FEL) and the linac-based self-amplified spontaneous emission (SASE) FEL for the two regimes, respectively. As previously discussed, target beam parameters are sigma sub x sub , sub y approx 10 mu m, sigma sub x sub ' sub , sub y sub ' =1 mu rad, and sigma sub t approx 1 ps (0.1 ps for the linac case). We report the use of few- to sub-angstrom radiation emitted by a 7-GeV beam transitting a 198-period diagnostics undulator and a bending magnet to characterize the particle beam. A particle beam divergence as low as sigma sub y sub ' =3.3 mu rad was measured using an X-ray monochromator. Additionally, a particle beam size of sigma sub y <45 mu m and a bunch length of sigma sub t =28 ps with 4-ps resolution were measured using an X-ray pinhole camera with a unique synchroscan and dual-sweep X-ray streak camera as the detector. The adjustable pinhole aper...

  14. CERN Developments for 704 MHz Superconducting Cavities

    CERN Document Server

    Capatina, O; Aviles Santillana, I; Arnau Izquierdo, G; Bonomi, R; Calatroni, S; Chambrillon, J; Gerigk, F; Garoby, R; Guinchard, M; Junginger, T; Malabaila, M; Marques Antunes Ferreira, L; Mikulas, S; Parma, V; Pillon, F; Renaglia, T; Schirm, K; Tardy, T; Therasse, M; Vacca, A; Valverde Alonso, N; Vande Craen, A

    2013-01-01

    The Superconducting Proton Linac (SPL) is an R&D effort coordinated by CERN in partnership with other international laboratories. It is aiming at developing key technologies for the construction of a multi-megawatt proton linac based on state-of-the-art RF superconducting technology, which would serve as a driver in new physics facilities for neutrinos and/or Radioactive Ion Beam (RIB). Amongst the main objectives of this R&D effort, is the development of 704 MHz bulk niobium beta=1 elliptical cavities, operating at 2 K with a maximum accelerating gradient of 25 MV/m, and the testing of a string of cavities integrated in a machine-type cryomodule. The cavity together with its helium tank had to be carefully designed in coherence with the innovative design of the cryomodule. New fabrication methods have also been explored. Five such niobium cavities and two copper cavities are in fabrication. The key design aspects are discussed, the results of the alternative fabrication methods presented and the stat...

  15. Quality of Intensity Modulated Radiation Therapy Treatment Plans Using a ⁶⁰Co Magnetic Resonance Image Guidance Radiation Therapy System.

    Science.gov (United States)

    Wooten, H Omar; Green, Olga; Yang, Min; DeWees, Todd; Kashani, Rojano; Olsen, Jeff; Michalski, Jeff; Yang, Deshan; Tanderup, Kari; Hu, Yanle; Li, H Harold; Mutic, Sasa

    2015-07-15

    This work describes a commercial treatment planning system, its technical features, and its capabilities for creating (60)Co intensity modulated radiation therapy (IMRT) treatment plans for a magnetic resonance image guidance radiation therapy (MR-IGRT) system. The ViewRay treatment planning system (Oakwood Village, OH) was used to create (60)Co IMRT treatment plans for 33 cancer patients with disease in the abdominal, pelvic, thorax, and head and neck regions using physician-specified patient-specific target coverage and organ at risk (OAR) objectives. Backup plans using a third-party linear accelerator (linac)-based planning system were also created. Plans were evaluated by attending physicians and approved for treatment. The (60)Co and linac plans were compared by evaluating conformity numbers (CN) with 100% and 95% of prescription reference doses and heterogeneity indices (HI) for planning target volumes (PTVs) and maximum, mean, and dose-volume histogram (DVH) values for OARs. All (60)Co IMRT plans achieved PTV coverage and OAR sparing that were similar to linac plans. PTV conformity for (60)Co was within 20 Gy. The mean doses for all (60)Co plan OARs were within clinical tolerances. A commercial (60)Co MR-IGRT device can produce highly conformal IMRT treatment plans similar in quality to linac IMRT for a variety of disease sites. Additional work is in progress to evaluate the clinical benefit of other novel features of this MR-IGRT system. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Analytical bunch compression studies for FLUTE

    CERN Document Server

    Schreck, M

    2014-01-01

    The current article deals with analytical bunch compression studies for FLUTE whose results are compared to simulations. FLUTE is a linac-based electron accelerator with a design energy of approximately 40 MeV currently being constructed at the Karlsruhe Institute of Technology. One of the goals of FLUTE is to generate electron bunches with their length lying in the femtosecond regime. In the first phase this will be accomplished using a magnetic bunch compressor. This compressor forms the subject of the studies presented. The paper is divided into three parts. The first part deals with pure geometric investigations of the bunch compressor where space charge effects and the back reaction of bunches with coherent synchrotron radiation (CSR) are neglected. The second part is dedicated to the treatment of space charge effects and the third part gives some analytical results on the emission of CSR. The upshot is that the results of the first and the third part agree quite well with what is obtained from simulatio...

  17. A Comparison of Helical Intensity-Modulated Radiotherapy, Intensity-Modulated Radiotherapy, and 3D-Conformal Radiation Therapy for Pancreatic Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Poppe, Matthew M.; Narra, Venkat; Yue, Ning J.; Zhou Jinghao; Nelson, Carl [Department of Radiation Oncology, Huntsman Cancer Hospital, University of Utah, Salt Lake City, UT (United States); Department of Radiation Oncology, Cancer Institute of New Jersey, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick, NJ (United States); Jabbour, Salma K., E-mail: jabbousk@umdnj.edu [Department of Radiation Oncology, Huntsman Cancer Hospital, University of Utah, Salt Lake City, UT (United States); Department of Radiation Oncology, Cancer Institute of New Jersey, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick, NJ (United States)

    2011-01-01

    We assessed dosimetric differences in pancreatic cancer radiotherapy via helical intensity-modulated radiotherapy (HIMRT), linac-based IMRT, and 3D-conformal radiation therapy (3D-CRT) with regard to successful plan acceptance and dose to critical organs. Dosimetric analysis was performed in 16 pancreatic cases that were planned to 54 Gy; both post-pancreaticoduodenectomy (n = 8) and unresected (n = 8) cases were compared. Without volume modification, plans met constraints 75% of the time with HIMRT and IMRT and 13% with 3D-CRT. There was no statistically significantly improvement with HIMRT over conventional IMRT in reducing liver V35, stomach V45, or bowel V45. HIMRT offers improved planning target volume (PTV) dose homogeneity compared with IMRT, averaging a lower maximum dose and higher volume receiving the prescription dose (D100). HIMRT showed an increased mean dose over IMRT to bowel and liver. Both HIMRT and IMRT offer a statistically significant improvement over 3D-CRT in lowering dose to liver, stomach, and bowel. The results were similar for both unresected and resected patients. In pancreatic cancer, HIMRT offers improved dose homogeneity over conventional IMRT and several significant benefits to 3D-CRT. Factors to consider before incorporating IMRT into pancreatic cancer therapy are respiratory motion, dose inhomogeneity, and mean dose.

  18. Analysis of High Order Modes in 1.3 GHZ CW SRF Electron Linac for a Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Sukhanov, A. [Fermilab; Vostrikov, A. [Fermilab; Yakovlev, V. [Fermilab

    2013-01-01

    Design of a Light Source (LS) based on the continuous wave superconducting RF (CW SRF) electron linac is currently underway. This facility will provide soft coherent X-ray radiation for a braod spectrum of basic research applications. Quality of the X-ray laser radiation is affected by the electron beam parameters such as the stability of the transverse beam position and longitudinal and transverse beam emittances. High order modes (HOMs) excited in the SRF structures by a passing beam may deteriorate the beam quality and affect the beam stability. Deposition of HOM energy in the walls of SRF cavities adds to the heat load of he cryogenic system and leads to the increased cost of building and operation of the linac. In this paper we evaluate effects of HOMs in an LS CW SRF linac based on Tesla-type 9-cell 1.3 GHz cavities. We analyze non-coherent losses and resonance excitation of HOMs. We estimate heat load due to the very high frequency HOMs. We study influence of the HOMs on the transverse beam dynamics.

  19. Deliverable D3 - Low- and Medium-beta linac

    CERN Document Server

    A. Facco, A. Balabin, R. Paparella, D. Zenere, INFN-Laboratori Nazionali di Legnaro, Padova, Italy; D. Berkovits, J. Rodnizki, SOREQ, Yavne, Israel; J. L. Biarrotte, S. Bousson, A. Ponton, G. Olry, IPN Orsay, France; R. Duperrier, D. Uriot, CEA/Saclay, France; V. Zvyagintsev, TRIUMF, Vancouver, Canada.

    The present document describes the Low- and Medium-beta section of the EURISOL DS Driver Accelerator. This section consists of a superconducting linac, based on Half-Wave (HWR) and SPOKE type resonators, preceded by a short, normal-conducting MEBT (Medium Energy Beam Transport) section that performs input beam matching. The scope of this linac is to bring the beams of H-, D+ and 3He++ produced by the Ion Injector (Deliverable D-5) to the energy and beam parameters required for injection in the superconducting High-beta linac (Deliverable D4-High beta linac). The present beam dynamics design reaches the goal of accelerating the required high current beams to the design energy (about 100 MeV/A, depending on the ion species), with minimum emittance growth and with low losses, using realistic and cost-effective, although innovative, technological solutions. The Low- and Medium-beta linac layout is described, together with the fundamental parameters and characteristics of its components and the system performanc...

  20. Deliverable D3 - Low- and Medium-beta linac

    CERN Document Server

    A. Facco, A. Balabin, R. Paparella, D. Zenere, INFN-Laboratori Nazionali di Legnaro, Padova, Italy; D. Berkovits, J. Rodnizki, SOREQ, Yavne, Israel; J. L. Biarrotte, S. Bousson, A. Ponton, G. Olry, IPN Orsay, France; R. Duperrier, D. Uriot, CEA/Saclay, France; V. Zvyagintsev, TRIUMF, Vancouver, Canada.

    The present document describes the Low- and Medium-beta section of the EURISOL DS Driver Accelerator. This section consists of a superconducting linac, based on Half-Wave (HWR) and SPOKE type resonators, preceded by a short, normal-conducting MEBT (Medium Energy Beam Transport) section that performs input beam matching. The scope of this linac is to bring the beams of H-, D+ and 3He++ produced by the Ion Injector (Deliverable D-5) to the energy and beam parameters required for injection in the superconducting High-beta linac (Deliverable D4-High beta linac). The present beam dynamics design reaches the goal of accelerating the required high current beams to the design energy (about 100 MeV/A, depending on the ion species), with minimum emittance growth and with low losses, using realistic and cost-effective, although innovative, technological solutions. The Low- and Medium-beta linac layout is described, together with the fundamental parameters and characteristics of its components and the system performance.

  1. Neutron time-of-flight spectroscopy measurement using a waveform digitizer

    Science.gov (United States)

    Liu, Long-Xiang; Wang, Hong-Wei; Ma, Yu-Gang; Cao, Xi-Guang; Cai, Xiang-Zhou; Chen, Jin-Gen; Zhang, Gui-Lin; Han, Jian-Long; Zhang, Guo-Qiang; Hu, Ji-Feng; Wang, Xiao-He

    2016-05-01

    The photoneutron source (PNS, phase 1), an electron linear accelerator (linac)-based pulsed neutron facility that uses the time-of-flight (TOF) technique, was constructed for the acquisition of nuclear data from the Thorium Molten Salt Reactor (TMSR) at the Shanghai Institute of Applied Physics (SINAP). The neutron detector signal used for TOF calculation, with information on the pulse arrival time, pulse shape, and pulse height, was recorded by using a waveform digitizer (WFD). By using the pulse height and pulse-shape discrimination (PSD) analysis to identify neutrons and γ-rays, the neutron TOF spectrum was obtained by employing a simple electronic design, and a new WFD-based DAQ system was developed and tested in this commissioning experiment. The DAQ system developed is characterized by a very high efficiency with respect to millisecond neutron TOF spectroscopy. Supported by Strategic Priority Research Program of the Chinese Academy of Science(TMSR) (XDA02010100), National Natural Science Foundation of China(NSFC)(11475245,No.11305239), Shanghai Key Laboratory of Particle Physics and Cosmology (11DZ2260700)

  2. Evaluation of nuclear data for R and D projects; development of database for medical nuclear data

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Tae Suk [Catholic University, Seoul (Korea); Shin, D. O. [Kyung Hee University, Seoul (Korea); Joh, C. W.; Chang, J. S. [Ajou University, Suwon (Korea); Choi, Y. [Sungkyunkwan University, Seoul (Korea); Kim, S. H. [Hanyang University, Seoul (Korea); Park, S. Y. [National Cancer Center, Seoul (Korea); Shin, D. H.; Lee, S [Kyonggi University, Seoul (Korea)

    2002-04-01

    Medical nuclear data used in the country is not provided by academic associations and organizations concerned and even by government organizations concerned. This is aimed to investigate the diagnostic and therapeutic equipments in the clinical use and the domestic present status of nuclear data and physical properties of sealed or unsealed radioactive isotopes and to establish the nuclear database. About 120 domestic centers take nuclear medicine tests and 52 medical centers do radiotherapy. The 30-odd different kinds of radionuclides are usually used in nuclear medicine in the country. The 30-odd kinds of unsealed sources are used for diagnosis and therapy and 10-odd kinds of sealed sources for brachytherapy in the country. The special radiotherapy includes Gamma-knife, linac-based stereotactic radiosurgery, conformal radiotherapy and Intensity modulated radiotherapy. The nuclear data base has been completed on the basis of these data collected and the web site made is available with ease to anyone who want to get nuclear data. 39 refs., 20 figs., 8 tabs. (Author)

  3. Time-resolved pump-probe experiments at the LCLS

    Energy Technology Data Exchange (ETDEWEB)

    Glownia, James; /SLAC /Stanford U., Appl. Phys. Dept.; Cryan, J.; /SLAC /Stanford U., Phys. Dept.; Andreasson, J.; /Uppsala U.; Belkacem, A.; /LBNL, Berkeley; Berrah, N.; /Western Michigan U.; Blaga, C.L.; /Ohio State U.; Bostedt, C.; Bozek, J.; /SLAC; DiMauro, L.F.; /Ohio State U.; Fang, L.; /Western Michigan U.; Frisch, J.; /SLAC; Gessner, O.; /LBNL; Guhr, M.; /SLAC; Hajdu, J.; /Uppsala U.; Hertlein, M.P.; /LBNL; Hoener, M.; /Western Michigan U. /LBNL; Huang, G.; Kornilov, O.; /LBNL; Marangos, J.P.; /Imperial Coll., London; March, A.M.; /Argonne; McFarland, B.K.; /SLAC /Stanford U., Phys. Dept. /SLAC /IRAMIS, Saclay /Stanford U., Phys. Dept. /Georgia Tech /Argonne /Kansas State U. /SLAC /Stanford U., Phys. Dept. /SLAC /Stanford U., Appl. Phys. Dept. /Stanford U., Appl. Phys. Dept. /SLAC /LBNL /Argonne /SLAC /SLAC /Stanford U., Appl. Phys. Dept. /Stanford U., Phys. Dept.

    2011-08-12

    The first time-resolved x-ray/optical pump-probe experiments at the SLAC Linac Coherent Light Source (LCLS) used a combination of feedback methods and post-analysis binning techniques to synchronize an ultrafast optical laser to the linac-based x-ray laser. Transient molecular nitrogen alignment revival features were resolved in time-dependent x-ray-induced fragmentation spectra. These alignment features were used to find the temporal overlap of the pump and probe pulses. The strong-field dissociation of x-ray generated quasi-bound molecular dications was used to establish the residual timing jitter. This analysis shows that the relative arrival time of the Ti:Sapphire laser and the x-ray pulses had a distribution with a standard deviation of approximately 120 fs. The largest contribution to the jitter noise spectrum was the locking of the laser oscillator to the reference RF of the accelerator, which suggests that simple technical improvements could reduce the jitter to better than 50 fs.

  4. submitter Introduction to Collective Effects in Particle Accelerators

    CERN Document Server

    Zimmermann, Frank

    2016-01-01

    The beam intensity and the beam brightness of particle accelerators or colliders operated for high - energy physics were, and are, often severely limited by “collective effects” (e.g.[1]). By contrast, new light sources, such as linac - based free electron lasers, may even rely on collective instabilities to accomplish their mission! The term “collective effects” refers to the interaction of beam particles with each other through a variety of processes, e.g. (1) non-delayed self-fields and image fields present even for constant perfectly conducting and magnetic boundaries (direct and indirect “space - charge effects”), (2) longer - lived electro-magnetic “wake fields” due to a finite chamber resistivity or geometric variation in the beam - pipe cross section, which typically affect later parts of the beam, (3) coherent synchrotron radiation, which on a curved trajectory may even influence earlier parts of the beam, giving rise to “non-causal” wake fields, otherwise not normally encountered...

  5. RF study and 3-D simulations of a side-coupling thermionic RF-gun

    Science.gov (United States)

    Rimjaem, S.; Kusoljariyakul, K.; Thongbai, C.

    2014-02-01

    A thermionic RF-gun for generating ultra-short electron bunches was optimized, developed and used as a source at a linac-based THz radiation research laboratory of the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The RF-gun is a π/2-mode standing wave structure, which consists of two S-band accelerating cells and a side-coupling cavity. The 2856 MHz RF wave is supplied from an S-band klystron to the gun through the waveguide input-port at the cylindrical wall of the second cell. A fraction of the RF power is coupled from the second cell to the first one via a side-coupling cavity. Both the waveguide input-port and the side-coupling cavity lead to an asymmetric geometry of the gun. RF properties and electromagnetic field distributions inside the RF-gun were studied and numerically simulated by using computer codes SUPERFISH 7.19 and CST Microwave Studio 2012©. RF characterizations and tunings of the RF-gun were performed to ensure the reliability of the gun operation. The results from 3D simulations and measurements are compared and discussed in this paper. The influence of asymmetric field distributions inside the RF-gun on the electron beam properties was investigated via 3D beam dynamics simulations. A change in the coupling-plane of the side-coupling cavity is suggested to improve the gun performance.

  6. RF study and 3-D simulations of a side-coupling thermionic RF-gun

    Energy Technology Data Exchange (ETDEWEB)

    Rimjaem, S., E-mail: sakhorn.rimjaem@cmu.ac.th [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics (ThEP), Commission on Higher Education, Bangkok 10400 (Thailand); Kusoljariyakul, K.; Thongbai, C. [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics (ThEP), Commission on Higher Education, Bangkok 10400 (Thailand)

    2014-02-01

    A thermionic RF-gun for generating ultra-short electron bunches was optimized, developed and used as a source at a linac-based THz radiation research laboratory of the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The RF-gun is a π/2-mode standing wave structure, which consists of two S-band accelerating cells and a side-coupling cavity. The 2856 MHz RF wave is supplied from an S-band klystron to the gun through the waveguide input-port at the cylindrical wall of the second cell. A fraction of the RF power is coupled from the second cell to the first one via a side-coupling cavity. Both the waveguide input-port and the side-coupling cavity lead to an asymmetric geometry of the gun. RF properties and electromagnetic field distributions inside the RF-gun were studied and numerically simulated by using computer codes SUPERFISH 7.19 and CST Microwave Studio 2012{sup ©}. RF characterizations and tunings of the RF-gun were performed to ensure the reliability of the gun operation. The results from 3D simulations and measurements are compared and discussed in this paper. The influence of asymmetric field distributions inside the RF-gun on the electron beam properties was investigated via 3D beam dynamics simulations. A change in the coupling-plane of the side-coupling cavity is suggested to improve the gun performance.

  7. Advances in radiation oncology in new millennium in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Seung Jae [College of Medicine, Sungkyunkwan Univ., Seoul (Korea, Republic of); Park, Charn Il [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of)

    2000-06-01

    The objective of recent radiation therapy is to improve the quality of treatment and the after treatment quality of life. In Korea, sharing the same objective, significant advancement was made due to the gradual increase of patient number and rapid increase of treatment facilities. The advancement includes generalization of three-dimensional conformal radiotherapy (3D-CRT), application of linac-based stereotactic radiosurgery (SRS), and furthermore, the introduction of intensity modulated radiation therapy (IMRT). Authors in this paper prospectively review the followings: the advancement of radiation oncology in Korea, the recent status of four-dimensional radiation therapy. IMRT, the concept of the treatment with biological conformity, the trend of combined chemoradiotherapy, the importance of internet and radiation oncology information management system as influenced by the revolution of information technology, and finally the global trend of telemedicine in radiation oncology. Additionally, we suggest the methods to improve radiotherapy treatment, which include improvement of quality assurance (QA) measures by developing Koreanized QA protocol and system, regional study about clinical protocol development for phase three clinical trial, suggestion of unified treatment protocol and guideline by academic or research societies, domestic generation of treatment equipment's or system, establishment of nationwide data base of radiation-oncology-related information, and finally pattems-of-care study about major cancers.

  8. X-ray tomography system for industrial applications

    Science.gov (United States)

    Auditore, L.; Barna, R. C.; Emanuele, U.; Loria, D.; Trifiro, A.; Trimarchi, M.

    2008-05-01

    X-ray radiography and tomography are two of the most used non-destructive testing techniques both in industrial and cultural heritage fields. However, the inspection of heavy materials or thick objects requires X-ray energies larger than the maximum energy provided by commercial X-ray tubes (600 kV). For this reason, and owing to the long experience of the INFN-Gruppo Collegato di Messina in designing and assembling low energy electron linacs, a 5 MeV electron linac based X-ray tomographic system has been developed at the Dipartimento di Fisica, Università di Messina. The X-ray source, properly designed, provides a 16 cm diameter X-ray spot at the sample position, and a beam opening angle of about 3.6 degree. Optimization of the parameters influencing the e-γ conversion and the X-ray beam characteristics have been studied by means of the MCNP-4C2 (Monte-Carlo-N-Particle, version 4C2) code. The image acquisition system consists of a CCD camera and a scintillator screen. Preliminary radiographies and tomographies showing the high quality performances of the tomographic system have been acquired. Finally, the compactness of the accelerator system is one of the advantages of the discussed tomography device which could be made transportable.

  9. High-intensity positron microprobe at Jefferson Lab

    CERN Document Server

    Golge, Serkan; Wojtsekhowski, Bogdan

    2014-01-01

    We present a conceptual design for a novel continuous wave electron-linac based high-intensity slow-positron production source with a projected intensity on the order of 10$^{10}$ e$^+$/s. Reaching this intensity in our design relies on the transport of positrons (T$_+$ below 600 keV) from the electron-positron pair production converter target to a low-radiation and low-temperature area for moderation in a high-efficiency cryogenic rare gas moderator, solid Ne. The performance of the integrated beamline has been verified through computational studies. The computational results include Monte Carlo calculations of the optimized electron/positron beam energies, converter target thickness, synchronized raster system, transport of the beam from the converter target to the moderator, extraction of the beam from the channel, and moderation efficiency calculations. For the extraction of positrons from the magnetic channel a magnetic field terminator plug prototype has been built and experimental data on the effective...

  10. X-ray Sources by Energy Recovered Linacs and Their Needed R&D

    Energy Technology Data Exchange (ETDEWEB)

    Geoffrey Krafft, Stephen Benson, Michael Borland, David Douglas, David Dowell, Carlos Hernandez-Garcia, Dmitry Kayran, Robert Legg, Elizabeth Moog, Takashi Obina, Robert Rimmer, Vitaly Yakimenko

    2011-05-01

    In this paper we review the current state of research on energy recovered linacs as drivers for future X-ray sources. For many types of user experiments, such sources may have substantial advantages compared to the workhorse sources of the present: high energy storage rings. Energy recovered linacs need to be improved beyond present experience in both energy and average current to support this application. To build an energy recovered linac based X-ray user facility presents many interesting challenges. We present summaries on the Research and Development (R&D) topics needed for full development of such a source, including the discussion at the Future Light Sources Workshop held in Gaithersberg, Maryland on September 15-17, 2009. A first iteration of an R&D plan is presented that is founded on the notion of building a set of succeedingly larger test accelerators exploring cathode physics, high average current injector physics, and beam recirculation and beam energy recovery at high average current. Our basic conclusion is that a reviewable design of such a source can be developed after an R&D period of reasonably short duration.

  11. A proposed VUV oscillator-based FEL upgrade at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Benson, S. V. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Douglas, D. R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Evtushenko, P. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Hannon, F. E. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Hernandez-Garcia, C. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Klopf, J. M. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Legg, R. A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Neil, G. R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Shinn, M. D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Tennant, C. D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Zhang, S. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Williams, G. P. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2011-09-20

    Advances in superconducting linac technology offer the possibility of an upgrade of the Jefferson Lab Free Electron Laser (JLab FEL) facility to an oscillator-based VUV-FEL that would produce 6 x 10{sup 12} coherent 100 eV photons per pulse at multi-MHz repetition rates in the fundamental. At present JLab operates a pair of oscillator-based continuous-wave Free Electron Lasers (FELs) as a linac-based next generation light source in the IR and UV, with sub-picosecond pulses up to 75 MHz. Harmonics upwards of 10 eV are produced and the fully coherent nature of the source results in peak and average brightness values that are several orders of magnitude higher than storage rings. The accelerator uses an energy recovered linac design for efficiency of operation. New style superconducting linac cryomodules with higher gradient, combined with a new injector and beam transport system allow the development of the FEL to higher photon energies.

  12. High Frequency Linacs for Hadrontherapy

    Science.gov (United States)

    Amaldi, Ugo; Braccini, Saverio; Puggioni, Paolo

    The use of radiofrequency linacs for hadrontherapy was proposed about 20 years ago, but only recently has it been understood that the high repetition rate together with the possibility of very rapid energy variations offers an optimal solution to the present challenge of hadrontherapy: "paint" a moving tumor target in three dimensions with a pencil beam. Moreover, the fact that the energy, and thus the particle range, can be electronically adjusted implies that no absorber-based energy selection system is needed, which, in the case of cyclotron-based centers, is the cause of material activation. On the other side, a linac consumes less power than a synchrotron. The first part of this article describes the main advantages of high frequency linacs in hadrontherapy, the early design studies, and the construction and test of the first high-gradient prototype which accelerated protons. The second part illustrates some technical issues relevant to the design of copper standing wave accelerators, the present developments, and two designs of linac-based proton and carbon ion facilities. Superconductive linacs are not discussed, since nanoampere currents are sufficient for therapy. In the last two sections, a comparison with circular accelerators and an overview of future projects are presented.

  13. Beam dynamics and expected performance of Sweden’s new storage-ring light source: MAX IV

    Directory of Open Access Journals (Sweden)

    S. C. Leemann

    2009-12-01

    Full Text Available MAX IV will be Sweden’s next-generation high-performance synchrotron radiation source. The project has recently been granted funding and construction is scheduled to begin in 2010. User operation for a broad and international user community should commence in 2015. The facility is comprised of two storage rings optimized for different wavelength ranges, a linac-based short-pulse facility and a free-electron laser for the production of coherent radiation. The main radiation source of MAX IV will be a 528 m ultralow emittance storage ring operated at 3 GeV for the generation of high-brightness hard x rays. This storage ring was designed to meet the requirements of state-of-the-art insertion devices which will be installed in nineteen 5 m long dispersion-free straight sections. The storage ring is based on a novel multibend achromat design delivering an unprecedented horizontal bare lattice emittance of 0.33 nm rad and a vertical emittance below the 8 pm rad diffraction limit for 1 Å radiation. In this paper we present the beam dynamics considerations behind this storage-ring design and detail its expected unique performance.

  14. lightsources.org: An Internet Site for Light SourceCommunication

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Art

    2004-10-04

    Research at the world's accelerator- (storage-ring and linac) based light sources is one of the most dynamic and rapidly growing fields of science. It frequently results in direct benefits to society, thereby demonstrating the value of the research with very concrete examples, but this is not widely understood or appreciated outside of the immediate user community. Our growing group of light source communicators from facilities in Europe, Asia, and the Americas, inspired by the Interactions.org Web site created by high-energy (elementary-particle)physics communicators, concluded that a light source community Web site (lightsources.org) would be the best tool for establishing effective collaboration between the communications offices of the world's light sources and to maximize the impact of our efforts. We envision lightsources.org to serve as a one-stop-shopping site for information about all aspects of light sources and the research they make possible. Audiences to be served include science communicators, the press, policymakers, the light source community, the wider scientific community, the science-interested public, and students and educators. Our proposal has been sent to the world's light source facility directors by J. Murray Gibson (APS) and William G. Stirling (ESRF). As a result,light sources.org is now being supported by a growing list of facilities from Europe, North America, and Asia. We hope to launch lightsources.org before the end of 2004.

  15. Active Interrogation using Photofission Technique for Nuclear Materials Control and Accountability

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Haori [Oregon State Univ., Corvallis, OR (United States)

    2016-03-31

    Innovative systems with increased sensitivity and resolution are in great demand to detect diversion and to prevent misuse in support of nuclear materials management for the U.S. fuel cycle. Nuclear fission is the most important multiplicative process involved in non-destructive active interrogation. This process produces the most easily recognizable signature for nuclear materials. In addition to thermal or high-energy neutrons, high-energy gamma rays can also excite a nucleus and cause fission through a process known as photofission. Electron linear accelerators (linacs) are widely used as the interrogating photon sources for inspection methods involving photofission technique. After photofission reactions, prompt signals are much stronger than the delayed signals, but it is difficult to quantify them in practical measurements. Delayed signals are easily distinguishable from the interrogating radiation. linac-based, advanced inspection techniques utilizing the delayed signals after photofission have been extensively studied for homeland security applications. Previous research also showed that a unique delayed gamma ray energy spectrum exists for each fissionable isotope.

  16. Beam-Based Procedures for RF Guns

    CERN Document Server

    Krasilnikov, Mikhail; Grabosch, H J; Hartrott, Michael; Hui Han, Jang; Miltchev, Velizar; Oppelt, Anne; Petrosyan, Bagrat; Staykov, Lazar; Stephan, Frank

    2005-01-01

    A wide range of rf photo injector parameters has to be optimized in order to achieve an electron source performance as required for linac based high gain FELs. Some of the machine parameters can not be precisely controlled by direct measurements, whereas the tolerance on them is extremely tight. Therefore, this should be met with beam-based techniques. Procedures for beam-based alignment (BBA) of the laser on the photo cathode as well as solenoid alignment have been developed. They were applied at the Photo Injector Test facility at DESY Zeuthen (PITZ) and at the photo injector of the VUV-FEL at DESY Hamburg. A field balance of the accelerating mode in the 1 ½ cell gun cavity is one of the key beam dynamics issues of the rf gun. Since no direct field measurement in the half and full cell of the cavity is available for the PITZ gun, a beam-based technique to determine the field balance has been proposed. A beam-based rf phase monitoring procedure has been developed as well.

  17. Beam dynamics study of a 30 MeV electron linear accelerator to drive a neutron source

    Science.gov (United States)

    Kumar, Sandeep; Yang, Haeryong; Kang, Heung-Sik

    2014-02-01

    An experimental neutron facility based on 32 MeV/18.47 kW electron linac has been studied by means of PARMELA simulation code. Beam dynamics study for a traveling wave constant gradient electron accelerator is carried out to reach the preferential operation parameters (E = 30 MeV, P = 18 kW, dE/E E-gun, pre-buncher, buncher, and 2 accelerating columns. A disk-loaded, on-axis-coupled, 2π/3-mode type accelerating rf cavity is considered for this linac. After numerous optimizations of linac parameters, 32 MeV beam energy is obtained at the end of the linac. As high electron energy is required to produce acceptable neutron flux. The final neutron flux is estimated to be 5 × 1011 n/cm2/s/mA. Future development will be the real design of a 30 MeV electron linac based on S band traveling wave.

  18. Beam dynamics study of a 30 MeV electron linear accelerator to drive a neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sandeep; Yang, Haeryong; Kang, Heung-Sik, E-mail: hskang@postech.ac.kr [Pohang Accelerator Laboratory, San31, Hyoja-dong, Pohang, Gyeongbuk 790-784 (Korea, Republic of)

    2014-02-14

    An experimental neutron facility based on 32 MeV/18.47 kW electron linac has been studied by means of PARMELA simulation code. Beam dynamics study for a traveling wave constant gradient electron accelerator is carried out to reach the preferential operation parameters (E = 30 MeV, P = 18 kW, dE/E < 12.47% for 99% particles). The whole linac comprises mainly E-gun, pre-buncher, buncher, and 2 accelerating columns. A disk-loaded, on-axis-coupled, 2π/3-mode type accelerating rf cavity is considered for this linac. After numerous optimizations of linac parameters, 32 MeV beam energy is obtained at the end of the linac. As high electron energy is required to produce acceptable neutron flux. The final neutron flux is estimated to be 5 × 10{sup 11} n/cm{sup 2}/s/mA. Future development will be the real design of a 30 MeV electron linac based on S band traveling wave.

  19. Design and parameter optimization of a small-scale electron-based ADS for radioactive waste transmutation

    Science.gov (United States)

    Feizi, H.; Ranjbar, A. H.

    2015-05-01

    This paper presents the design and feasibility of an electron-LINAC-based small-scale system (ADS) for nuclear waste transmutation. FLUKA simulations have been performed to evaluate the photoneutron yield in high- Z metallic targets such as silver, tungsten, lead, tantalum and uranium irradiated by electron beams of 20-200MeV. The parameters involved in the photoneutron production mechanism including electron beam energy, target material and target shape have been investigated in order to obtain maximum photoneutron production. The neutron reflectors of the ADS, in particular, beryllium, lead and beryllium oxide (BeO) with various thicknesses have been studied. The results show that a combination of an internal reflector of Pb with a thickness of 3cm and an external reflector of BeO with a thickness of 10cm improves the fluence rate. The photoneutron energy spectrum, photoneutron fluence distribution and heat deposition in the electron target have also been presented. At incident electron beam energy of 155MeV, a neutron source of ˜ 4.6 × 1010 (n/cm2/s/mA) has been achieved, which is highly applicable for using in nuclear waste transmutation. The designed ADS has the ability to transmute ˜ 1.5 × 1022 (atoms/y/mA). The obtained results are promising and could lead to the development of a small-scale ADS based on electron LINAC for radioactive waste transmutation and for numerous applications when employed as a photoneutron source.

  20. CyberKnife radiosurgery: Precision without incision

    Directory of Open Access Journals (Sweden)

    Enja Siva Prasad Reddy

    2015-01-01

    Full Text Available CyberKnife stereotactic radiosurgery system is an innovative, effective, frameless, non-invasive substitute for conventional surgical treatment of cancer. It works on the principle of stereotaxy. It is used for the treatment of both cancerous and non-cancerous tumors, intracranial lesions, tumors of lung, spine, prostate, and kidney, recurrent cases of oral squamous cell carcinoma, arteriovenous malformation, and trigeminal neuralgia. It has an advantage over other systems like Gamma knife radiosurgery and linear accelerator (LINAC-based systems, as it is frameless, has submillimeter accuracy, does not affect the normal cells adjacent to the lesion, and tracks the lesion in synchronization with the patient′s respiratory rate. The future of CyberKnife encompasses possibilities such as incremental improvements in accuracy and better shaping of the field of radiation and would certainly allow extension of radiosurgery as an effective substitute for chemotherapy. This paper aims to review and highlight the immense potential that CyberKnife holds in the field of dentistry in treating disorders of the head and neck region, thereby ensuring enhanced longevity for the patients.

  1. Seeding the FEL of the SCSS Phase 1 Facility with the 13th Laser Harmonic of a Ti-Sa Laser Produced in Xe Gas

    CERN Document Server

    Lambert, G

    2005-01-01

    In order to reach very short wavelengths in systems based on Free Electrons Laser (FEL), and to have a more compact, fully coherent and tunable source, a particular seeding configuration is studied here. It is foreseen to test it as a demonstration experiment in 2006 into the SCSS phase 1 facility (Spring-8 Compact Sase Source, Japan). SCSS phase 1 is a linac-based FEL project, providing a compact SASE source with high brightness in the X-ray range. The external laser source, which is employed, is straightfully in the XUV range, the 13th harmonic of a Ti:Sa femtosecond laser (61.5 nm), generated in Xe gas. This harmonic can be now easily generated by focusing the Ti: Sa laser (25 mJ, 10 Hz, 100 fs) on a 10 Hz pulsed Xe gas cell. This High order Harmonics Generation (HHG) process provides us with a VUV beam with intense (1 μJ) and ultra-short (50 fs) properties.

  2. Preliminary study of EEHG-based superradiant undulator radiation at the HLS-II storage ring

    Science.gov (United States)

    Gao, Wei-Wei; Li, He-Ting; Wang, Lin

    2017-07-01

    We investigate storage ring-based Echo-Enabled Harmonic Generation (EEHG) superradiant undulator radiation as a possible scheme to obtain shorter wavelengths at the HLS-II (Hefei Light Source-II) storage ring. In this paper we give the designation of the storage ring based EEHG up to the 26th harmonic, where 31 nm vacuum ultraviolet light is radiated from an 800 nm seeded laser. The novelty of our design is that both the two dispersion sections of EEHG are realized by the storage ring’s own magnet structure. In particular, the whole ring is used as the first dispersion section, and two modulators of the traditional EEHG can be done with the same undulator. These two dispersion sections are realized by changing the superperiod of the present lattice structure, and more precisely by changing the focusing strengths of the present structure. Since no additional magnets and chicanes are used, the beam circulates around the storage ring repeatedly, and thus this storage ring-based EEHG can have a higher repetition rate than a linac-based EEHG. Supported by National Natural Science Foundation of China (11305170)

  3. Overview of High Power Vacuum Dry RF Load Designs

    Energy Technology Data Exchange (ETDEWEB)

    Krasnykh, Anatoly [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-27

    A specific feature of RF linacs based on the pulsed traveling wave (TW) mode of operation is that only a portion of the RF energy is used for the beam acceleration. The residual RF energy has to be terminated into an RF load. Higher accelerating gradients require higher RF sources and RF loads, which can stably terminate the residual RF power. RF feeders (from the RF source though the accelerating section to the load) are vacuumed to transmit multi-megawatt high power RF. This overview will outline vacuumed RF loads only. A common method to terminate multi-MW RF power is to use circulated water (or other liquid) as an absorbing medium. A solid dielectric interface (a high quality ceramic) is required to separate vacuum and liquid RF absorber mediums. Using such RF load approaches in TW linacs is troubling because there is a fragile ceramic window barrier and a failure could become catastrophic for linac vacuum and RF systems. Traditional loads comprising of a ceramic disk have limited peak and average power handling capability and are therefore not suitable for high gradient TW linacs. This overview will focus on ''vacuum dry'' or ''all-metal'' loads that do not employ any dielectric interface between vacuum and absorber. The first prototype is an original design of RF loads for the Stanford Two-Mile Accelerator.

  4. Design of APhF-IH Linac for a Compact Medical Accelerator

    CERN Document Server

    Kapin, V; Iwata, Y

    2003-01-01

    The design of a small injection linac for a compact medical synchrotron is discussed. The linac design is based on interdigital H-type (IH) drift-tube structure with alternative phase focusing (APhF). A high acceleration rate and an absence of magnetic lenses inside drift-tubes reduce the cost and length of APhF-IH linac in comparison with HIMAC linac based on Alvarez structure with magnet quadrupoles inside drift-tubes. To reduce effects of emittance growth, the RFQ structure is used in front of the APhF linac. In such linac layout, the current transmission of a carbon beam can reach up to 90-100%. In this report, the basic parameters of whole linac are presented, while the design of APhF structure is considered in details. Two reference designs of 4 MeV/u 200 MHz APhF linacs with different voltage distributions along the whole tank have been generated and analyzed numerically. For the first design, a constant voltage distribution along the tank is assumed. The total length of the structure is about 4.2 m. F...

  5. Design study of the bending sections between harmonic cascade FEL stages

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Weishi; Corlett, John; Fawley, William; Zholents, A.

    2004-06-30

    The present design of LUX (linac based ultra-fast X-ray facility) includes a harmonic cascade FEL chain to generate coherent EUV and soft X-ray radiation. Four cascade stages, each consisting of two undulators acting as a modulator and a radiator, respectively, are envisioned to produce photons of approximate wavelengths 48 nm, 12 nm, 4 nm and 1 nm. Bending sections may be placed between the modulator and the radiator of each stage to adjust and maintain bunching of the electrons, to separate, in space, photons of different wavelengths and to optimize the use of real estate. In this note, the conceptual design of such a bending section, which may be used at all four stages, is presented. Preliminary tracking results show that it is possible to maintain bunch structure of nm length scale in the presence of errors, provided that there is adequate orbit correction and there are 2 families of trim quads and trim skew quads, respectively, in each bending section.

  6. Status of the Superconducting Proton Linac (SPL) Cryo-Module

    CERN Document Server

    Parma, V; Capatina, O; Chambrillon, J; Montesinos, E; Schirm, K; Vande Craen, A; Vandoni, G; Van Weelderen, R

    2014-01-01

    The Superconducting Proton Linac (SPL) is an R&D effort conducted by CERN in partnership with other international laboratories, aimed at developing key technologies for the construction of a multi-megawatt proton linac based on state-of-the-art SRF technology. Such an accelerator could serve as a driver in new physics facilities for neutrinos and/or radioactive ion beams [1]. Amongst the main objectives of this effort, are the development of 704 MHz bulk niobium beta=1 elliptical cavities (operating at 2 K and providing an accelerating gradient of 25 MV/m) and the test of a string of cavities integrated in a machine-type cryo-module. In an initial phase, only four out of the eight cavities of the SPL cryo-module will be tested in a half-length cryo-module developed for this purpose, which nonetheless preserves the main features of the full size module. This paper presents the final design of the cryo-module and the status of the construction of the main cryostat parts. Preliminary plans for the assembly a...

  7. Investigation of slice emittance using an energy-chirped electron beam in a dispersive section for photo injector characterization at PITZ

    Energy Technology Data Exchange (ETDEWEB)

    Ivanisenko, Yevgeniy

    2012-06-15

    This work describes a transverse slice emittance diagnostics with an RMS temporal resolution down to 2 ps that was implemented at the Photo Injector Test facility in Zeuthen (PITZ). The measurements were performed for several bunch charges generated by a laser pulse that has a flat-top temporal profile of 21-22 ps FWHM duration. This diagnostics allows to study the beam projected emittance compensation with a solenoid magnetic field experimentally and therefore contributes to the beam emittance optimization for the needs of short wavelength linac-based FELs in particular. The diagnostics is based upon the usage of electron bunches which have a correlation between the longitudinal position and the momentum of the bunch particles. This property allows to convert the bunch longitudinal distribution into a transverse one in a dipole magnet. A slit with a narrow opening at the dipole exit selects a fraction of the particle ensemble, a slice, which emittance is analyzed at a screen downstream. Slit scan and quadrupole scan techniques can be used to measure the emittance of the slices. In the experiments it was found that the slice emittance values are 5-10% lower than the projected emittance values, indicating a good effectivity of the solenoid compensation. The emittance obtained using quadrupole scan technique has shown different results when compared to slit scan technique due to a beam halo. The observed beam halo in phase space contributes up to 40% of the emittance value while having only 10% of the bunch charge.

  8. Initial studies of Bremsstrahlung energy deposition in small-bore superconducting undulator structures in linac environments

    Energy Technology Data Exchange (ETDEWEB)

    Cremer, T.; Tatchyn, R. [Stanford Univ., CA (United States)

    1995-12-31

    One of the more promising technologies for developing minimal-length insertion devices for linac-driven, single-pass Free Electron Lasers (FELs) operating in the x-ray range is based on the use of superconducting (SC) materials. In recent FEL simulations, for example, a bifilar helical SC device with a 2 cm period and 1.8 T field was found to require a 30 m saturation length for operation at 1.5{Angstrom} on a 15 GeV linac, more than 40% shorter than an alternative hybrid/permanent magnet (hybrid/PM) undulator. AT the same time, however, SC technology is known to present characteristic difficulties for insertion device design, both in engineering detail and in operation. Perhaps the most critical problem, as observed, e.g., by Madey and co-workers in their initial FEL experiments, was the frequent quenching induced by scattered electrons upstream of their (bifilar) device. Postulating that this quenching was precipitated by directly-scattered or bremsstrahlung-induced particle energy deposited into the SC material or into material contiguous with it, the importance of numerical and experimental characterizations of this phenomenon for linac-based, user-facility SC undulator design becomes evident. In this paper we discuss selected prior experimental results and report on initial EGS4 code studies of scattered and bremsstrahlung induced particle energy deposition into SC structures with geometries comparable to a small-bore bifilar helical undulator.

  9. NATO Advanced Research Workshop

    CERN Document Server

    Wiedemann, Helmut

    2006-01-01

    This book covers latest development in theory and experiments of unconventional radiation production. Specifically, the generation of Tera-Hertz and X-ray radiation from low energy electron beams in the form of Channeling, Transition, Diffraction, Cherenkov, Smith-Purcell, PXR and Crystalline Undulator Radiation are presented. Material characteristics like thin targets, curved or bend crystals, inhomogeneous and left handed materials, multilayers as well as stimulation by external radiation are covered to demonstrate their influence in these processes. Novel ideas are offered on the use of such radiation in detectors and particle beam monitor development with improved energy or time resolution. The book assumes some familiarity of the reader with theoretical concepts underlying these phenomena and is therefore of primary use to the practicing scientist. More fundamental discussions of these phenomena can be found in the 2002 monograph "Electron-Photon Interaction in Dense Media" within the NATO Science Series...

  10. Circuit quantum electrodynamics architecture for gate-defined quantum dots in silicon

    Science.gov (United States)

    Mi, X.; Cady, J. V.; Zajac, D. M.; Stehlik, J.; Edge, L. F.; Petta, J. R.

    2017-01-01

    We demonstrate a hybrid device architecture where the charge states in a double quantum dot (DQD) formed in a Si/SiGe heterostructure are read out using an on-chip superconducting microwave cavity. A quality factor Q = 5400 is achieved by selectively etching away regions of the quantum well and by reducing photon losses through low-pass filtering of the gate bias lines. Homodyne measurements of the cavity transmission reveal DQD charge stability diagrams and a charge-cavity coupling rate gc/2 π= 23 MHz. These measurements indicate that electrons trapped in a Si DQD can be effectively coupled to microwave photons, potentially enabling coherent electron-photon interactions in silicon.

  11. Conversion of zero point energy into high-energy photons

    Energy Technology Data Exchange (ETDEWEB)

    Ivlev, B. I. [Universidad Autonoma de San Luis Potosi, Instituto de Fisica, Av. Manuel Nava No. 6, Zona Universitaria, 78290 San Luis Potosi, SLP (Mexico)

    2016-11-01

    An unusual phenomenon, observed in experiments is studied. X-ray laser bursts of keV energy are emitted from a metal where long-living states, resulting in population inversion, are totally unexpected. Anomalous electron-photon states are revealed to be formed inside the metal. These states are associated with narrow, 10{sup -11} cm, potential well created by the local reduction of zero point electromagnetic energy. In contrast to analogous van der Waals potential well, leading to attraction of two hydrogen atoms, the depth of the anomalous well is on the order of 1 MeV. The states in that well are long-living which results in population inversion and subsequent laser generation observed. The X-ray emission, occurring in transitions to lower levels, is due to the conversion of zero point electromagnetic energy. (Author)

  12. The use of Monte Carlo technique to optimize the dose distribution in total skin irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Poli, M.E.R. E-mail: esmeraldapoli@hotmail.com; Pereira, S.A.; Yoriyaz, H

    2001-06-01

    Cutaneous T-cell lymphoma (mycosis fungoides) is an indolent disease with a low percentage of cure. Total skin irradiation using an electron beam has become an efficient treatment of mycosis fungoides with curative intention, with success in almost 40% of the patients. In this work, we propose the use of a Monte Carlo technique to simulate the dose distribution in the patients during total skin irradiation treatments. Use was made of MCNP-4B, a well known and established code used to simulate transport of electrons, photons and neutrons through matter, especially in the area of reactor physics, and also finding increasing utility in medical physics. The goal of our work is to simulate different angles between each beam with a fixed treatment distance in order to obtain a uniform dose distribution in the patient.

  13. Breeding new light into old machines (and new)

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, J.E.; Brodsky, S.J.

    1985-04-01

    Photons produced by lasers or wigglers backscattered on high energy electron or proton beams can provide high energy, high luminosity photon-electron, photon-photon or photon-proton collisions. This allows the study of short-distance QCD processes such as high transverse momentum photon-photon and photo-production reactions, deep inelastic Compton scattering, the photon structure function, direct photon reactions, or searches for pseudo-Goldstone bosons and supersymmetry particles like the photino or goldstino. The relative reaction rates should be quite high since (1) photo-production cross sections are significantly larger than the corresponding electro-production cross sections and (2) absence of the conventional beam-beam interaction allows significantly higher currents and smaller interaction areas. It thus seems possible to have photon luminosities much larger than for electrons. Examples are given using the PEP storage ring with the SLAC linac beam.

  14. Compact Photon Source for Polarized Target Experiments

    Science.gov (United States)

    Niculescu, Gabriel; Wojtsekhowski, Bogdan

    2017-01-01

    High energy photon beams are one of the tools of choice in nuclear and particle physics. However, most of the current techniques used for producing such beams have substantial drawbacks that limit their usefulness (low intensity, large beam size, mixed electron-photon beams). In this presentation we will outline the design of a Compact Photon Source (CPS) capable of providing narrow ( 1 mm) untagged photon beams of an intensity suitable for carrying out polarized target experiments. Compared with existing technology the CPS will provide a substantial (10-100) increase in the figure-of-merit. While optimized for a Wide Angle Compton Scattering experiment proposed at JLab, the source described here can be used in a variety of photon-induced physics experiments as well as for industrial applications.

  15. Low-power chip-level optical interconnects based on bulk-silicon single-chip photonic transceivers

    Science.gov (United States)

    Kim, Gyungock; Park, Hyundai; Joo, Jiho; Jang, Ki-Seok; Kwack, Myung-Joon; Kim, Sanghoon; Kim, In Gyoo; Kim, Sun Ae; Oh, Jin Hyuk; Park, Jaegyu; Kim, Sanggi

    2016-03-01

    We present new scheme for chip-level photonic I/Os, based on monolithically integrated vertical photonic devices on bulk silicon, which increases the integration level of PICs to a complete photonic transceiver (TRx) including chip-level light source. A prototype of the single-chip photonic TRx based on a bulk silicon substrate demonstrated 20 Gb/s low power chip-level optical interconnects between fabricated chips, proving that this scheme can offer compact low-cost chip-level I/O solutions and have a significant impact on practical electronic-photonic integration in high performance computers (HPC), cpu-memory interface, 3D-IC, and LAN/SAN/data-center and network applications.

  16. The FOREST detector for meson photoproduction experiments at ELPH

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, T., E-mail: ishikawa@lns.tohoku.ac.jp [Research Center for Electron Photon Science (ELPH), Tohoku University, Sendai 982–0826 (Japan); Fujimura, H.; Fukasawa, H.; Hashimoto, R.; Ishida, T.; Kaida, S.; Kasagi, J. [Research Center for Electron Photon Science (ELPH), Tohoku University, Sendai 982–0826 (Japan); Kawano, A. [Department of Information Science, Tohoku Gakuin University, Sendai 981–3193 (Japan); Kuwasaki, S. [Research Center for Electron Photon Science (ELPH), Tohoku University, Sendai 982–0826 (Japan); Maeda, K. [Department of Physics, Tohoku University, Sendai 980–8578 (Japan); Miyahara, F.; Mochizuki, K.; Nakabayashi, T.; Nakamura, A.; Nawa, K.; Ogushi, S.; Okada, Y.; Okamura, K.; Onodera, Y.; Saito, Y. [Research Center for Electron Photon Science (ELPH), Tohoku University, Sendai 982–0826 (Japan); and others

    2016-10-01

    An electromagnetic calorimeter complex, FOREST, has been constructed for meson photoproduction experiments at the Research Center for Electron Photon Science, Tohoku University. It consists of three types of calorimeters, which are made of pure cesium-iodide crystals, lead scintillating-fiber modules, and lead glass Cherenkov counters. Each calorimeter is equipped with a plastic scintillator hodoscope to identify charged particles. The design and performance of FOREST are described. The energy responses of test calorimeters have been investigated by using 100–800 MeV positron beams. The energy resolutions of the three calorimeters are found to be approximately 3%, 7%, and 5% for 1-GeV photons, respectively. A cryogenic hydrogen/deuterium target system fitted to the FOREST experiments and a newly developed data acquisition system are also presented.

  17. Study of some superconducting and magnetic materials on high T sub c oxide superconductors

    Science.gov (United States)

    Wu, M. K.

    1987-01-01

    On the basis of existing data it appears that the high-temperature superconductivity above 77 K reported here, occurs only in compound systems consisting of a phase other than the K2NiF4 phase. A narrow superconducting transition was obtained with T sub c0 = 98 K and T sub c1 = 94 K in Y-Ba-Cu-O (YBCO). Preliminary results indicate that YBCO is rather different from the layered LaBCO, LaSCO, and LaCCO. While electron-photon interaction cannot be absent from this compound system, nonconventional enhanced superconducting interactions due to interfaces, Resonating Valence Bond (RVB) states, or even a superconducting state beyond the BCS framework, may be required to account for the high T sub c in YBCO. It is believed that study of the possible subtle correlation between magnetism and superconductivity will definitely provide important insight into the superconducting mechanism in YBCO and other oxides.

  18. Robust Topological Terahertz Circuits using Semiconductors

    CERN Document Server

    Bahari, Babak; Kanté, Boubacar

    2016-01-01

    Topological Insulator-based devices can transport electrons/photons at the surfaces of materials without any back reflections, even in the presence of obstacles. Topological properties have recently been studied using non-reciprocal materials such as gyromagnetics or using bianisotropy. However, these effects usually saturate at optical frequencies and limit our ability to scale down devices. In order to implement topological devices that we introduce in this paper for the terahertz range, we show that semiconductors can be utilized via their cyclotron resonance in combination with small magnetic fields. We propose novel terahertz operating devices such as the topological tunable power splitter and the topological circulator. This work opens new perspectives in the design of terahertz integrated devices and circuits with high functionality.

  19. MUSiC. A model unspecific search in CMS based on 2010 LHC data

    Energy Technology Data Exchange (ETDEWEB)

    Pieta, Holger

    2012-06-20

    A Model Unspecific Search in CMS (MUSiC) is presented in this work, along with its results on the data taken in 2010 by the Compact Muon Solenoid (CMS) at the Large Hadron Collider (LHC). This analysis shows a sensitivity to various models for new physics and provides a broad view at the data, due to its minimal theoretical bias. Events are classified with respect to their reconstructed objects: Muons, electrons, photons, jets and missing transverse energy. Up to three kinematic variables in each of these classes are systematically scanned for continuous bin regions deviating significantly from the predictions by the Standard Model of particle physics. No deviations beyond expected fluctuations are observed, when taking systematic uncertainties into account. The sensitivity of the analysis to certain models beyond the Standard Model is demonstrated.

  20. Dual-readout Calorimetry

    CERN Document Server

    Akchurin, N; Cardini, A.; Cascella, M.; Cei, F.; De Pedis, D.; Fracchia, S.; Franchino, S.; Fraternali, M.; Gaudio, G.; Genova, P.; Hauptman, J.; La Rotonda, L.; Lee, S.; Livan, M.; Meoni, E.; Moggi, A.; Pinci, D.; Policicchio, A.; Saraiva, J.G.; Sill, A.; Venturelli, T.; Wigmans, R.

    2013-01-01

    The RD52 Project at CERN is a pure instrumentation experiment whose goal is to un- derstand the fundamental limitations to hadronic energy resolution, and other aspects of energy measurement, in high energy calorimeters. We have found that dual-readout calorimetry provides heretofore unprecedented information event-by-event for energy resolution, linearity of response, ease and robustness of calibration, fidelity of data, and particle identification, including energy lost to binding energy in nuclear break-up. We believe that hadronic energy resolutions of {\\sigma}/E $\\approx$ 1 - 2% are within reach for dual-readout calorimeters, enabling for the first time comparable measurement preci- sions on electrons, photons, muons, and quarks (jets). We briefly describe our current progress and near-term future plans. Complete information on all aspects of our work is available at the RD52 website http://highenergy.phys.ttu.edu/dream/.

  1. Surface Plasmon Nanophotonics

    CERN Document Server

    Brongersma, Mark L

    2007-01-01

    The development of advanced dielectric photonic structures has enabled tremendous control over the propagation and manipulation of light. Structures such as waveguides, splitters, mixers, and resonators now play a central role in the telecommunications industry. This book will discuss an exciting new class of photonic devices, known as surface plasmon nanophotonic structures. Surface plasmons are easily accessible excitations in metals and semiconductors and involve a collective motion of the conduction electrons. These excitations can be exploited to manipulate electromagnetic waves at optical frequencies ("light") in new ways that are unthinkable in conventional dielectric structures. The field of plasmon nanophotonics is rapidly developing and impacting a wide range of areas including: electronics, photonics, chemistry, biology, and medicine. The book will highlight several exciting new discoveries that have been made, while providing a clear discussion of the underlying physics, the nanofabrication issues...

  2. Academic Training - The use of Monte Carlo radiation transport codes in radiation physics and dosimetry

    CERN Multimedia

    Françoise Benz

    2006-01-01

    2005-2006 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 27, 28, 29 June 11:00-12:00 - TH Conference Room, bldg. 4 The use of Monte Carlo radiation transport codes in radiation physics and dosimetry F. Salvat Gavalda,Univ. de Barcelona, A. FERRARI, CERN-AB, M. SILARI, CERN-SC Lecture 1. Transport and interaction of electromagnetic radiation F. Salvat Gavalda,Univ. de Barcelona Interaction models and simulation schemes implemented in modern Monte Carlo codes for the simulation of coupled electron-photon transport will be briefly reviewed. Different schemes for simulating electron transport will be discussed. Condensed algorithms, which rely on multiple-scattering theories, are comparatively fast, but less accurate than mixed algorithms, in which hard interactions (with energy loss or angular deflection larger than certain cut-off values) are simulated individually. The reliability, and limitations, of electron-interaction models and multiple-scattering theories will be analyzed. Benchmark comparisons of simu...

  3. In situ formation of cobalt oxide nanocubanes as efficient oxygen evolution catalysts.

    Science.gov (United States)

    Hutchings, Gregory S; Zhang, Yan; Li, Jian; Yonemoto, Bryan T; Zhou, Xinggui; Zhu, Kake; Jiao, Feng

    2015-04-01

    Oxygen evolution from water poses a significant challenge in solar fuel production because it requires an efficient catalyst to bridge the one-electron photon capture process with the four-electron oxygen evolution reaction (OER). Here, a new strategy was developed to synthesize nonsupported ultrasmall cobalt oxide nanocubanes through an in situ phase transformation mechanism using a layered Co(OH)(OCH3) precursor. Under sonication, the precursor was exfoliated and transformed into cobalt oxide nanocubanes in the presence of NaHCO3-Na2SiF6 buffer solution. The resulting cobalt catalyst with an average particle size less than 2 nm exhibited a turnover frequency of 0.023 per second per cobalt in photocatalytic water oxidation. X-ray absorption results suggested a unique nanocubane structure, where 13 cobalt atoms fully coordinated with oxygen in an octahedral arrangement to form 8 Co4O4 cubanes, which may be responsible for the exceptionally high OER activity.

  4. High spatial and temporal resolution photon/electron counting detector for synchrotron radiation research

    Science.gov (United States)

    Tremsin, A. S.; Lebedev, G. V.; Siegmund, O. H. W.; Vallerga, J. V.; Hull, J. S.; McPhate, J. B.; Jozwiak, C.; Chen, Y.; Guo, J. H.; Shen, Z. X.; Hussain, Z.

    2007-10-01

    This paper reports on the development of a high resolution electron/photon/ion imaging system which detects events with a timing accuracy of <160 ps FWHM and a two-dimensional spatial accuracy of ˜50 μm FWHM. The event counting detector uses microchannel plates for signal amplification and can sustain counting rates exceeding 1.5 MHz for evenly distributed events (0.4 MHz with 10% dead time for randomly distributed events). The detector combined with a time-of-flight angular resolved photoelectron energy analyzer was tested at a synchrotron beamline. The results of these measurements illustrate the unique capabilities of the analytical system, allowing simultaneous imaging of photoelectrons in momentum space and measurement of the energy spectrum, as well as filtering the data in user defined temporal and/or spatial windows.

  5. Performance of ATLAS L1 Calorimeter Trigger with data

    CERN Document Server

    Bracinik, J; The ATLAS collaboration

    2010-01-01

    The ATLAS first-level calorimeter trigger is a hardware-based system designed to identify high-pT jets, electron/photon and tau candidates and to measure total and missing ET in the ATLAS calorimeters. After more than two years of commissioning in situ with calibration data and cosmic rays, the system has now been extensively used to select the most interesting proton-proton collision events. Final tuning of timing and energy calibration has been carried out in 2010 to improve the trigger response to physics objects. An analysis of the performance of the level-1 calorimeter trigger will be presented, along with the techniques used to achieve these results.

  6. The performance of the ATLAS Level-1 Calorimeter Trigger with LHC collision data

    CERN Document Server

    Bracinik, J

    2011-01-01

    The ATLAS first-level calorimeter trigger is a hardware-based system designed to identify high-E$_T$ jets, electron/photon and $ au$ candidates and to measure total and missing E$_T$ in the ATLAS calorimeters. After more than two years of commissioning in situ with calibration data and cosmic rays, the system has now been used extensively to select the most interesting proton-proton collision events. Fine tuning of timing and energy calibration has been carried out in 2010 to improve the trigger response to physics objects. In these proceedings, an analysis of the performance of the level-1 calorimeter trigger is presented, along with the techniques used to achieve these results.

  7. Spectrally and Spatially Resolved Smith-Purcell Radiation in Plasmonic Crystals with Short-Range Disorder

    Science.gov (United States)

    Kaminer, I.; Kooi, S. E.; Shiloh, R.; Zhen, B.; Shen, Y.; López, J. J.; Remez, R.; Skirlo, S. A.; Yang, Y.; Joannopoulos, J. D.; Arie, A.; Soljačić, M.

    2017-01-01

    Electrons interacting with plasmonic structures can give rise to resonant excitations in localized plasmonic cavities and to collective excitations in periodic structures. We investigate the presence of resonant features and disorder in the conventional Smith-Purcell effect (electrons interacting with periodic structures) and observe the simultaneous excitation of both the plasmonic resonances and the collective excitations. For this purpose, we introduce a new scanning-electron-microscope-based setup that allows us to probe and directly image new features of electron-photon interactions in nanophotonic structures like plasmonic crystals with strong disorder. Our work creates new possibilities for probing nanostructures with free electrons, with potential applications that include tunable sources of short-wavelength radiation and plasmonic-based particle accelerators.

  8. The use of Monte Carlo radiation transport codes in radiation physics and dosimetry

    CERN Document Server

    CERN. Geneva; Ferrari, Alfredo; Silari, Marco

    2006-01-01

    Transport and interaction of electromagnetic radiation Interaction models and simulation schemes implemented in modern Monte Carlo codes for the simulation of coupled electron-photon transport will be briefly reviewed. In these codes, photon transport is simulated by using the detailed scheme, i.e., interaction by interaction. Detailed simulation is easy to implement, and the reliability of the results is only limited by the accuracy of the adopted cross sections. Simulations of electron and positron transport are more difficult, because these particles undergo a large number of interactions in the course of their slowing down. Different schemes for simulating electron transport will be discussed. Condensed algorithms, which rely on multiple-scattering theories, are comparatively fast, but less accurate than mixed algorithms, in which hard interactions (with energy loss or angular deflection larger than certain cut-off values) are simulated individually. The reliability, and limitations, of electron-interacti...

  9. A single probe for imaging photons, electrons and physical forces

    Science.gov (United States)

    Pilet, Nicolas; Lisunova, Yuliya; Lamattina, Fabio; Stevenson, Stephanie E.; Pigozzi, Giancarlo; Paruch, Patrycja; Fink, Rainer H.; Hug, Hans J.; Quitmann, Christoph; Raabe, Joerg

    2016-06-01

    The combination of complementary measurement techniques has become a frequent approach to improve scientific knowledge. Pairing of the high lateral resolution scanning force microscopy (SFM) with the spectroscopic information accessible through scanning transmission soft x-ray microscopy (STXM) permits assessing physical and chemical material properties with high spatial resolution. We present progress from the NanoXAS instrument towards using an SFM probe as an x-ray detector for STXM measurements. Just by the variation of one parameter, the SFM probe can be utilised to detect either sample photo-emitted electrons or transmitted photons. This allows the use of a single probe to detect electrons, photons and physical forces of interest. We also show recent progress and demonstrate the current limitations of using a high aspect ratio coaxial SFM probe to detect photo-emitted electrons with very high lateral resolution. Novel probe designs are proposed to further progress in using an SFM probe as a STXM detector.

  10. Improvement of density resolution in short-pulse hard x-ray radiographic imaging using detector stacks

    Science.gov (United States)

    Borm, B.; Gärtner, F.; Khaghani, D.; Neumayer, P.

    2016-09-01

    We demonstrate that stacking several imaging plates (IPs) constitutes an easy method to increase hard x-ray detection efficiency. Used to record x-ray radiographic images produced by an intense-laser driven hard x-ray backlighter source, the IP stacks resulted in a significant improvement of the radiograph density resolution. We attribute this to the higher quantum efficiency of the combined detectors, leading to a reduced photon noise. Electron-photon transport simulations of the interaction processes in the detector reproduce the observed contrast improvement. Increasing the detection efficiency to enhance radiographic imaging capabilities is equally effective as increasing the x-ray source yield, e.g., by a larger drive laser energy.

  11. Angle-Resolved Light-Matter Interaction in Anisotropic Layered Black Phosphorus

    Science.gov (United States)

    Huang, Shengxi; Ling, Xi; Hasdeo, Eddwi; Liang, Liangbo; Parkin, William; Tatsumi, Yuki; Nugraha, Ahmad; Puretzky, Alexander; Das, Paul; Sumpter, Bobby; Geohegan, David; Kong, Jing; Saito, Riichiro; Drndic, Marija; Meunier, Vincent; Dresselhaus, Mildred

    Orthorhombic black phosphorus (BP) and other layered materials, such as gallium telluride and tin selenide, stand out among two-dimensional (2D) materials owing to their anisotropic in-plane structure. This anisotropy adds a new dimension to the properties of 2D materials and stimulates the development of angle-resolved photonics and electronics. However, understanding the effect of anisotropy has remained unsatisfactory to-date, as shown by a number of inconsistencies in the recent literature. We use angle-resolved absorption and Raman spectroscopies to investigate the role of anisotropy on the electron-photon and electron-phonon interactions in BP. We highlight, both experimentally and theoretically, a non-trivial dependence between anisotropies and flake thickness, photon and phonon energies. We show that the anisotropic optical absorption is a reliable and simple way to identify the crystalline orientation of BP, which cannot be determined from Raman spectroscopy without the explicit consideration of excitation wavelength and flake thickness.

  12. Origin of coherent G -band phonon spectra in single-wall carbon nanotubes

    Science.gov (United States)

    Nugraha, A. R. T.; Hasdeo, E. H.; Sanders, G. D.; Stanton, C. J.; Saito, R.

    2015-01-01

    Coherent phonons in single-wall carbon nanotubes (SWNTs) are observed as oscillations of the differential absorption coefficient as a function of time by means of pump-probe spectroscopy. For the radial breathing mode (RBM) of a SWNT, the coherent phonon signal is understood to be a result of the modulated diameter-dependent energy gaps due to the coherent RBM phonon oscillations. However, this mechanism might not be the dominant contribution to other phonon modes in the SWNT. In particular, for the G -band phonons, which correspond to bond-stretching motions, we find that the modulation of the interatomic optical dipole (electron-photon) matrix element gives rise to a strong coherent G -band phonon intensity comparable to the coherent RBM phonon intensity. We also further discuss the dependence of coherent G -band and RBM phonon amplitudes on the laser excitation pulse width.

  13. Geant4 Low Energy Electromagnetic Physics

    Institute of Scientific and Technical Information of China (English)

    S.Chauvie; G.Depaola; 等

    2001-01-01

    Geant4 Low Energy Electromagnetic package Provides a precise treatment of electromagnetic interations of particles with matter down to very low energies (250 oV for electrons and photons,<1 keV for hadrons and ions),It includes a veriety of models for the electromagnetic processes of electrons,photons,hadrons and ions,taking into account advance features,such as shell effects and effects due to charge dependence.The comprehensive set of particle types it can handle,the variety of modeling approaches and the extended coverage of energy range make this package a unique tool among Monte Carlo codes on the market,and of relevance to serveral experimental domains in HIEP,astroparticle physics,space science and biomedical studies.

  14. Three-dimensional Aerographite-GaN hybrid networks: Single step fabrication of porous and mechanically flexible materials for multifunctional applications

    Science.gov (United States)

    Schuchardt, Arnim; Braniste, Tudor; Mishra, Yogendra K.; Deng, Mao; Mecklenburg, Matthias; Stevens-Kalceff, Marion A.; Raevschi, Simion; Schulte, Karl; Kienle, Lorenz; Adelung, Rainer; Tiginyanu, Ion

    2015-03-01

    Three dimensional (3D) elastic hybrid networks built from interconnected nano- and microstructure building units, in the form of semiconducting-carbonaceous materials, are potential candidates for advanced technological applications. However, fabrication of these 3D hybrid networks by simple and versatile methods is a challenging task due to the involvement of complex and multiple synthesis processes. In this paper, we demonstrate the growth of Aerographite-GaN 3D hybrid networks using ultralight and extremely porous carbon based Aerographite material as templates by a single step hydride vapor phase epitaxy process. The GaN nano- and microstructures grow on the surface of Aerographite tubes and follow the network architecture of the Aerographite template without agglomeration. The synthesized 3D networks are integrated with the properties from both, i.e., nanoscale GaN structures and Aerographite in the form of flexible and semiconducting composites which could be exploited as next generation materials for electronic, photonic, and sensors applications.

  15. Physics of nuclear radiations concepts, techniques and applications

    CERN Document Server

    Rangacharyulu, Chary

    2013-01-01

    Physics of Nuclear Radiations: Concepts, Techniques and Applications makes the physics of nuclear radiations accessible to students with a basic background in physics and mathematics. Rather than convince students one way or the other about the hazards of nuclear radiations, the text empowers them with tools to calculate and assess nuclear radiations and their impact. It discusses the meaning behind mathematical formulae as well as the areas in which the equations can be applied. After reviewing the physics preliminaries, the author addresses the growth and decay of nuclear radiations, the stability of nuclei or particles against radioactive transformations, and the behavior of heavy charged particles, electrons, photons, and neutrons. He then presents the nomenclature and physics reasoning of dosimetry, covers typical nuclear facilities (such as medical x-ray machines and particle accelerators), and describes the physics principles of diverse detectors. The book also discusses methods for measuring energy a...

  16. Cosmic ray physics goes to school

    CERN Multimedia

    2002-01-01

    With the help of a CERN physicist, German Schools bring the Largest Cosmic Ray Detector in Europe one step closer to reality   Eric Berthier and Robert Porret (CERN, ST/HM), Frej Torp and Christian Antfolk from the Polytechnics Arcada in Finland, and Karsten Eggert, physicist at CERN who initiated this project, during the installation of cosmic ray detectors in the Pays de Gex, at point 4. Niina Patrikainen and Frej Torp, Finnish students from Rovaniemi and Arcada Polytechnics, installing cosmic ray counters at the Fachhochschule in Duesseldorf. The science of cosmic ray detection is growing, literally. Cosmic rays, energetic particles from space, strike our planet all the time. They collide with the air molecules in our upper atmosphere and initiate large showers of elementary particles (mainly electrons, photons, hadrons and muons) which rain down upon the earth. The shower size and the particle density in the showers reflect the initial energy of the cosmic ray particle, a detail which makes d...

  17. Time-dependent density functional theory for many-electron systems interacting with cavity photons.

    Science.gov (United States)

    Tokatly, I V

    2013-06-07

    Time-dependent (current) density functional theory for many-electron systems strongly coupled to quantized electromagnetic modes of a microcavity is proposed. It is shown that the electron-photon wave function is a unique functional of the electronic (current) density and the expectation values of photonic coordinates. The Kohn-Sham system is constructed, which allows us to calculate the above basic variables by solving self-consistent equations for noninteracting particles. We suggest possible approximations for the exchange-correlation potentials and discuss implications of this approach for the theory of open quantum systems. In particular we show that it naturally leads to time-dependent density functional theory for systems coupled to the Caldeira-Leggett bath.

  18. ZnO nanoforms: The state-of-the art of synthetic strategies

    CERN Document Server

    Devaramani, Basavaraj S; Manjasetty, Babu A; Nair, Gopalakrishna T R

    2010-01-01

    Nanotechnology has already made indelible dents in the fields of communication, computation, electronics, photonics, gas sensors, diagnostic technologies, catalysis, drug delivery systems and imaging. In particular, ZnO nanostructures have attracted a lot of research interest due to their unique structure- and size-dependent electrical, optical, and mechanical properties. ZnO nanosystems are abundant with respect to a wide variety of morphologies whose syntheses are critically dependent on several experimental parameters. Cursory presentation of the immense potential of these tiny systems and the state-of-the-art of the synthetic methodologies along with our initial research on ZnO nanorods has been presented. ZnO nanorods in the size range 50-150nm have been synthesized by solid-state route by heating zinc acetate with caustic soda under specific growth conditions. X-ray diffraction pattern unequivocally establishes a wurtzite structure. Scanning electron microscope images of ZnO nanorods display a random di...

  19. The FOREST detector for meson photoproduction experiments at ELPH

    Science.gov (United States)

    Ishikawa, T.; Fujimura, H.; Fukasawa, H.; Hashimoto, R.; Ishida, T.; Kaida, S.; Kasagi, J.; Kawano, A.; Kuwasaki, S.; Maeda, K.; Miyahara, F.; Mochizuki, K.; Nakabayashi, T.; Nakamura, A.; Nawa, K.; Ogushi, S.; Okada, Y.; Okamura, K.; Onodera, Y.; Saito, Y.; Sakamoto, Y.; Sato, M.; Shimizu, H.; Sugai, H.; Suzuki, K.; Takahashi, S.; Tsuchikawa, Y.; Yamazaki, H.; Yonemura, H.

    2016-10-01

    An electromagnetic calorimeter complex, FOREST, has been constructed for meson photoproduction experiments at the Research Center for Electron Photon Science, Tohoku University. It consists of three types of calorimeters, which are made of pure cesium-iodide crystals, lead scintillating-fiber modules, and lead glass Cherenkov counters. Each calorimeter is equipped with a plastic scintillator hodoscope to identify charged particles. The design and performance of FOREST are described. The energy responses of test calorimeters have been investigated by using 100-800 MeV positron beams. The energy resolutions of the three calorimeters are found to be approximately 3%, 7%, and 5% for 1-GeV photons, respectively. A cryogenic hydrogen/deuterium target system fitted to the FOREST experiments and a newly developed data acquisition system are also presented.

  20. Improvement of density resolution in short-pulse hard x-ray radiographic imaging using detector stacks

    Energy Technology Data Exchange (ETDEWEB)

    Borm, B.; Gärtner, F.; Khaghani, D. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); Johann Wolfgang Goethe-Universität, Frankfurt am Main (Germany); Neumayer, P. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany)

    2016-09-15

    We demonstrate that stacking several imaging plates (IPs) constitutes an easy method to increase hard x-ray detection efficiency. Used to record x-ray radiographic images produced by an intense-laser driven hard x-ray backlighter source, the IP stacks resulted in a significant improvement of the radiograph density resolution. We attribute this to the higher quantum efficiency of the combined detectors, leading to a reduced photon noise. Electron-photon transport simulations of the interaction processes in the detector reproduce the observed contrast improvement. Increasing the detection efficiency to enhance radiographic imaging capabilities is equally effective as increasing the x-ray source yield, e.g., by a larger drive laser energy.

  1. Length-scale dependent phonon interactions

    CERN Document Server

    Srivastava, Gyaneshwar

    2014-01-01

    This book presents  a comprehensive description of phonons and their interactions in systems with different dimensions and length scales. Internationally-recognized leaders describe theories and measurements of phonon interactions  in relation to the design of materials with exotic properties such as metamaterials, nano-mechanical systems, next-generation electronic, photonic, and acoustic devices, energy harvesting, optical information storage, and applications of phonon lasers in a variety of fields. The emergence of techniques for control of semiconductor properties and geometry has enabled engineers to design structures in which functionality is derived from controlling electron behavior. As manufacturing techniques have greatly expanded the list of available materials and the range of attainable length scales, similar opportunities now exist for designing devices whose functionality is derived from controlling phonon behavior. However, progress in this area is hampered by gaps in our knowledge of phono...

  2. Atomic-force microscopy investigations of semiconductor nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Teichert, C. [Institute of Physics, University of Leoben (Austria); Brauer, G. [Institut f. Ionenstrahlphysik und Materialforschung, Forschungszentrum Rossendorf (Germany); Djurisic, A. [Department of Physics, University of Hong Kong (China); Sivakov, V.; Scholz, R. [Max Planck Institute of Microstructure Physics, Halle (Germany); Andrae, G. [Institute of Physical High Technology (IPHT), Jena (Germany); Christiansen, S.H. [Physics Department, Martin-Luther-University Halle-Wittenberg (Germany)

    2007-07-01

    One-dimensional nanostructures, such as nanorods or nanotubes, exhibit technological potential for many device applications like electronic, photonic or sensing devices. However, achieving control on the growth of such nanostructures leading to proper dimensional confinement (nanorods diameter, length, density and orientation) is still a challenging task. So far, scanning electron microscopy and transmission electron microscopy are the methods of choice to characterize arrays of free standing semiconductor nanowires. Atomic force microscopy - at a first glance - might not be suited for such a task. Analyzing arrays of vertical ZnO nanorods grown on Si and ITO substrates and individual Si nanowhiskers grown by electron beam evaporation on Si(111), we demonstrate the capabilities of atomic-force microscopy to yield integral information for example on the height variation of the nanorod arrays as well as detailed information on the facet structure of the nanowhiskers.

  3. The nucleon axial mass and the MiniBooNE CCQE neutrino-nucleus data

    CERN Document Server

    Nieves, J; Vicente-Vacas, M J

    2011-01-01

    We analyze the MiniBooNE CCQE $d\\sigma/dT_\\mu d\\cos\\theta_\\mu$ data using a theoretical model that has proved to be quite successful in the analysis of nuclear reactions with electron, photon and pion probes. We find that RPA and multinucleon knockout turn out to be essential for the description of the MiniBooNE data. We show these measurements are fully compatible with former determinations of nucleon axial mass $M_A$, in contrast with several previous analyses, which have suggested an anomalously large value. We find, $M_A=1.08 \\pm 0.03$ GeV. We also argue that the procedure, commonly used to reconstruct the neutrino energy for QE events from the muon angle and energy, could be unreliable for a wide region of the phase space, due to the large importance of multinucleon events.

  4. Performance of the ATLAS Trigger System in 2010

    CERN Document Server

    Aad, Georges; Abdallah, Jalal; Abdelalim, Ahmed Ali; Abdesselam, Abdelouahab; Abdinov, Ovsat; Abi, Babak; Abolins, Maris; Abramowicz, Halina; Abreu, Henso; Acerbi, Emilio; Acharya, Bobby Samir; Adams, David; Addy, Tetteh; Adelman, Jahred; Aderholz, Michael; Adomeit, Stefanie; Adragna, Paolo; Adye, Tim; Aefsky, Scott; Aguilar-Saavedra, Juan Antonio; Aharrouche, Mohamed; Ahlen, Steven; Ahles, Florian; Ahmad, Ashfaq; Ahsan, Mahsana; Aielli, Giulio; Akdogan, Taylan; Åkesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; Akiyama, Kunihiro; Alam, Mohammad; Alam, Muhammad Aftab; Albrand, Solveig; Aleksa, Martin; Aleksandrov, Igor; Alessandria, Franco; Alexa, Calin; Alexander, Gideon; Alexandre, Gauthier; Alexopoulos, Theodoros; Alhroob, Muhammad; Aliev, Malik; Alimonti, Gianluca; Alison, John; Aliyev, Magsud; Allport, Phillip; Allwood-Spiers, Sarah; Almond, John; Aloisio, Alberto; Alon, Raz; Alonso, Alejandro; Alviggi, Mariagrazia; Amako, Katsuya; Amaral, Pedro; Amelung, Christoph; Ammosov, Vladimir; Amorim, Antonio; Amorós, Gabriel; Amram, Nir; Anastopoulos, Christos; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Andrieux, Marie-Laure; Anduaga, Xabier; Angerami, Aaron; Anghinolfi, Francis; Anjos, Nuno; Annovi, Alberto; Antonaki, Ariadni; Antonelli, Mario; Antonelli, Stefano; Antonov, Alexey; Antos, Jaroslav; Anulli, Fabio; Aoun, Sahar; Aperio Bella, Ludovica; Apolle, Rudi; Arabidze, Giorgi; Aracena, Ignacio; Arai, Yasuo; Arce, Ayana; Archambault, John-Paul; Arfaoui, Samir; Arguin, Jean-Francois; Arik, Engin; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnault, Christian; Artamonov, Andrei; Artoni, Giacomo; Arutinov, David; Asai, Shoji; Asfandiyarov, Ruslan; Ask, Stefan; Åsman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astbury, Alan; Astvatsatourov, Anatoli; Atoian, Grigor; Aubert, Bernard; Auerbach, Benjamin; Auge, Etienne; Augsten, Kamil; Aurousseau, Mathieu; Austin, Nicholas; Avolio, Giuseppe; Avramidou, Rachel Maria; Axen, David; Ay, Cano; Azuelos, Georges; Azuma, Yuya; Baak, Max; Baccaglioni, Giuseppe; Bacci, Cesare; Bach, Andre; Bachacou, Henri; Bachas, Konstantinos; Bachy, Gerard; Backes, Moritz; Backhaus, Malte; Badescu, Elisabeta; Bagnaia, Paolo; Bahinipati, Seema; Bai, Yu; Bailey, David; Bain, Travis; Baines, John; Baker, Oliver Keith; Baker, Mark; Baker, Sarah; Baltasar Dos Santos Pedrosa, Fernando; Banas, Elzbieta; Banerjee, Piyali; Banerjee, Swagato; Banfi, Danilo; Bangert, Andrea Michelle; Bansal, Vikas; Bansil, Hardeep Singh; Barak, Liron; Baranov, Sergei; Barashkou, Andrei; Barbaro Galtieri, Angela; Barber, Tom; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Bardin, Dmitri; Barillari, Teresa; Barisonzi, Marcello; Barklow, Timothy; Barlow, Nick; Barnett, Bruce; Barnett, Michael; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barreiro, Fernando; Barreiro Guimarães da Costa, João; Barrillon, Pierre; Bartoldus, Rainer; Barton, Adam Edward; Bartsch, Detlef; Bartsch, Valeria; Bates, Richard; Batkova, Lucia; Batley, Richard; Battaglia, Andreas; Battistin, Michele; Battistoni, Giuseppe; Bauer, Florian; Bawa, Harinder Singh; Beare, Brian; Beau, Tristan; Beauchemin, Pierre-Hugues; Beccherle, Roberto; Bechtle, Philip; Beck, Hans Peter; Beckingham, Matthew; Becks, Karl-Heinz; Beddall, Andrew; Beddall, Ayda; Bedikian, Sourpouhi; Bednyakov, Vadim; Bee, Christopher; Begel, Michael; Behar Harpaz, Silvia; Behera, Prafulla; Beimforde, Michael; Belanger-Champagne, Camille; Bell, Paul; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellina, Francesco; Bellomo, Massimiliano; Belloni, Alberto; Beloborodova, Olga; Belotskiy, Konstantin; Beltramello, Olga; Ben Ami, Sagi; Benary, Odette; Benchekroun, Driss; Benchouk, Chafik; Bendel, Markus; Benedict, Brian Hugues; Benekos, Nektarios; Benhammou, Yan; Benjamin, Douglas; Benoit, Mathieu; Bensinger, James; Benslama, Kamal; Bentvelsen, Stan; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Berghaus, Frank; Berglund, Elina; Beringer, Jürg; Bernardet, Karim; Bernat, Pauline; Bernhard, Ralf; Bernius, Catrin; Berry, Tracey; Bertin, Antonio; Bertinelli, Francesco; Bertolucci, Federico; Besana, Maria Ilaria; Besson, Nathalie; Bethke, Siegfried; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianco, Michele; Biebel, Otmar; Bieniek, Stephen Paul; Biesiada, Jed; Biglietti, Michela; Bilokon, Halina; Bindi, Marcello; Binet, Sebastien; Bingul, Ahmet; Bini, Cesare; Biscarat, Catherine; Bitenc, Urban; Black, Kevin; Blair, Robert; Blanchard, Jean-Baptiste; Blanchot, Georges; Blazek, Tomas

    2012-01-01

    Proton-proton collisions at $\\sqrt{s}=7$ TeV and heavy ion collisions at $\\sqrt{s_{NN}}$=2.76 TeV were produced by the LHC and recorded using the ATLAS experiment's trigger system in 2010. The LHC is designed with a maximum bunch crossing rate of 40 MHz and the ATLAS trigger system is designed to record approximately 200 of these per second. The trigger system selects events by rapidly identifying signatures of muon, electron, photon, tau lepton, jet, and B meson candidates, as well as using global event signatures, such as missing transverse energy. An overview of the ATLAS trigger system, the evolution of the system during 2010 and the performance of the trigger system components and selections based on the 2010 collision data are shown. A brief outline of plans for the trigger system in 2011 is presented

  5. Energy exchange processes between electrons and photons in the strong radiation fields encountered in some astrophysical objects. I

    Energy Technology Data Exchange (ETDEWEB)

    Ter-Kazarian, G.T.

    1985-05-01

    The relaxation of a nonequilibrium isotropic radiation field which is interacting via multiphoton Compton scattering with a nonrelativistic degenerate equilibrium electron gas is investigated theoretically. It is pointed out that the multiphoton processes are often orders of magnitude more efficient than the single-photon process in astronomical objects such as radio pulsars and the pulsar NP 0532. The time variation of the photon distribution function is described by a kinetic equation which is formulated in terms of effective photons and shown to be consistent with the H theorem of Boltzmann by estimating the total-entropy change in the electron-photon system. The time variation of the total exchange energy and the electron-gas heating and cooling process are also analyzed. 17 references.

  6. Preface: Proceedings of the 21st International Workshop on Inelastic Ion-Surface Collisions (IISC-21)

    Science.gov (United States)

    Juaristi, J. I.; Alducin, M.

    2016-09-01

    This special issue contains the Proceedings of the 21st International Workshop on Inelastic Ion-Surface Collisions (IISC-21). The conference series started in 1976 and focuses on fundamental aspects of interactions of atoms, molecules, clusters and ions with surfaces. The main research themes are (a) energy loss of particles at surfaces, (b) charge exchange between particles and surfaces, (c) electron, photon and secondary ion emission due to particle impact on surfaces, (d) ion induced desorption, electronic and kinetic sputtering, (e) defect formation, surface modification and nanostructuring, (f) laser induced desorption, (g) scattering of atoms, ions, molecules and clusters, (h) sputtering, fragmentation, cluster and ion formation in SIMS and SNMS, and (i) cluster/molecular and highly charged ion beams.

  7. Ge-on-Si laser operating at room temperature.

    Science.gov (United States)

    Liu, Jifeng; Sun, Xiaochen; Camacho-Aguilera, Rodolfo; Kimerling, Lionel C; Michel, Jurgen

    2010-03-01

    Monolithic lasers on Si are ideal for high-volume and large-scale electronic-photonic integration. Ge is an interesting candidate owing to its pseudodirect gap properties and compatibility with Si complementary metal oxide semiconductor technology. Recently we have demonstrated room-temperature photoluminescence, electroluminescence, and optical gain from the direct gap transition of band-engineered Ge-on-Si using tensile strain and n-type doping. Here we report what we believe to be the first experimental observation of lasing from the direct gap transition of Ge-on-Si at room temperature using an edge-emitting waveguide device. The emission exhibited a gain spectrum of 1590-1610 nm, line narrowing and polarization evolution from a mixed TE/TM to predominantly TE with increasing gain, and a clear threshold behavior.

  8. Laser-driven electron beam and radiation sources for basic, medical and industrial sciences.

    Science.gov (United States)

    Nakajima, Kazuhisa

    2015-01-01

    To date active research on laser-driven plasma-based accelerators have achieved great progress on production of high-energy, high-quality electron and photon beams in a compact scale. Such laser plasma accelerators have been envisaged bringing a wide range of applications in basic, medical and industrial sciences. Here inheriting the groundbreaker's review article on "Laser Acceleration and its future" [Toshiki Tajima, (2010)],(1)) we would like to review recent progress of producing such electron beams due to relativistic laser-plasma interactions followed by laser wakefield acceleration and lead to the scaling formulas that are useful to design laser plasma accelerators with controllability of beam energy and charge. Lastly specific examples of such laser-driven electron/photon beam sources are illustrated.

  9. Model unspecific search for new physics in collision at $\\sqrt{s} = 7$ TeV

    Indian Academy of Sciences (India)

    Shivali Malhotra; Md Naimuddin; Thomas Hebbeker; Arnd Meyer; Holger Pieta; Paul Papacz; Stefan Antonius Schmitz; Mark Olschewski

    2012-11-01

    We present the results of a model-independent analysis, which systematically scans the data taken by CMS for deviations from the Standard Model (SM) predictions. Due to the minimal theoretical bias, this approach is sensitive to a variety of models for new physics. Events with at least one electron or muon are classified according to their content of reconstructed objects (muons, electrons, photons, jets and missing transverse energy). A broad scan of three kinematic distributions in those classes is performed by identifying deviations from SM expectations, accounting for systematic uncertainties. In this particular search, no significant discrepancies have been observed in data taken by CMS in 2010 and corresponding to an integrated luminosity of 36.1 pb-1.

  10. LHCb : First years of running for the LHCb calorimeter system and preparation for run 2

    CERN Multimedia

    Chefdeville, Maximilien

    2015-01-01

    The LHCb experiment is dedicated to precision measurements of CP violation and rare decays of B hadrons at the Large Hadron Collider (LHC) at CERN (Geneva). It comprises a calorimeter system composed of four subdetectors: a Scintillating Pad Detector (SPD) and a Pre-Shower detector (PS) in front of an electromagnetic calorimeter (ECAL) which is followed by a hadron calorimeter (HCAL). They are used to select transverse energy hadron, electron and photon candidates for the first trigger level and they provides the identification of electrons, photons and hadrons as well as the measurement of their energies and positions. The calorimeter has been pre-calibrated before its installation in the pit. The calibration techniques have been tested with data taken in 2010 and used regularly during run 1. For run 2, new calibration methods have been devised to follow and correct online the calorimeter detector response. The design and construction characteristics of the LHCb calorimeter will be recalled. Strategies for...

  11. Photonuclear and Radiation Effects Testing with a Refurbished 20 MeV Medical Electron Linac

    CERN Document Server

    Webb, Timothy; Beezhold, Wendland; De Veaux, Linda C; Harmon, Frank; Petrisko, Jill E; Spaulding, Randy

    2005-01-01

    An S-band 20 MeV electron linear accelerator formerly used for medical applications has been recommissioned to provide a wide range of photonuclear activation studies as well as various radiation effects on biological and microelectronic systems. Four radiation effect applications involving the electron/photon beams are described. Photonuclear activation of a stable isotope of oxygen provides an active means of characterizing polymer degradation. Biological irradiations of microorganisms including bacteria were used to study total dose and dose rate effects on survivability and the adaptation of these organisms to repeated exposures. Microelectronic devices including bipolar junction transistors (BJTs) and diodes were irradiated to study photocurrent from these devices as a function of peak dose rate with comparisons to computer modeling results. In addition, the 20 MeV linac may easily be converted to a medium energy neutron source which has been used to study neutron damage effects on transistors.

  12. Spectral Description of Multi-Photon Processes in Quantized Many-Electron Systems Based on a Reduced-Density-Matrix Approach

    Science.gov (United States)

    Jacobs, Verne

    2015-05-01

    The frequency-dependent transition rates for multi-photon processes in quantized many-electron systems are evaluated using a reduced-density-matrix approach. A fundamental foundation, based on quantum electrodynamics, is provided for systematic spectral simulations for electromagnetic interactions in quantized many-electron systems, including atomic, molecular, and solid-state systems. A perturbation expansion of the frequency-domain Liouville-space self-energy operator is employed in detailed evaluations of the spectral-line shapes. The self-energy contributions associated with environmental electron-photon and electron-phonon interactions are systematically taken into account. Detailed evaluations have been carried out for the spectral-line widths and shifts in the diagonal-resolvent, lowest order (Born), and short-memory-time (Markov) approximations. Work supported by the Office of Naval Research through the Basic Research Program at The Naval Research Laboratory.

  13. Unique properties of graphene quantum dots and their applications in photonic/electronic devices

    Science.gov (United States)

    Choi, Suk-Ho

    2017-03-01

    In recent years, graphene quantum dots (GQDs) have been recognized as an attractive building block for electronic, photonic, and bio-molecular device applications. This paper reports the current status of studies on the novel properties of GQDs and their hybrids with conventional and low-dimensional materials for device applications. In this review, more emphasis is placed on the structural, electronic, and optical properties of GQDs, and device structures based on the combination of GQDs with various semiconducting/insulating materials such as graphene, silicon dioxide, Si quantum dots, silica nanoparticles, organic materials, and so on. Because of GQDs’ unique properties, their hybrid structures are employed in high-efficiency devices, including photodetectors, solar cells, light-emitting diodes, flash memory, and sensors.

  14. Calorimetry triggering in ATLAS

    CERN Document Server

    Igonkina, O; Adragna, P; Aharrouche, M; Alexandre, G; Andrei, V; Anduaga, X; Aracena, I; Backlund, S; Baines, J; Barnett, B M; Bauss, B; Bee, C; Behera, P; Bell, P; Bendel, M; Benslama, K; Berry, T; Bogaerts, A; Bohm, C; Bold, T; Booth, J R A; Bosman, M; Boyd, J; Bracinik, J; Brawn, I, P; Brelier, B; Brooks, W; Brunet, S; Bucci, F; Casadei, D; Casado, P; Cerri, A; Charlton, D G; Childers, J T; Collins, N J; Conde Muino, P; Coura Torres, R; Cranmer, K; Curtis, C J; Czyczula, Z; Dam, M; Damazio, D; Davis, A O; De Santo, A; Degenhardt, J; Delsart, P A; Demers, S; Demirkoz, B; Di Mattia, A; Diaz, M; Djilkibaev, R; Dobson, E; Dova, M, T; Dufour, M A; Eckweiler, S; Ehrenfeld, W; Eifert, T; Eisenhandler, E; Ellis, N; Emeliyanov, D; Enoque Ferreira de Lima, D; Faulkner, P J W; Ferland, J; Flacher, H; Fleckner, J E; Flowerdew, M; Fonseca-Martin, T; Fratina, S; Fhlisch, F; Gadomski, S; Gallacher, M P; Garitaonandia Elejabarrieta, H; Gee, C N P; George, S; Gillman, A R; Goncalo, R; Grabowska-Bold, I; Groll, M; Gringer, C; Hadley, D R; Haller, J; Hamilton, A; Hanke, P; Hauser, R; Hellman, S; Hidvgi, A; Hillier, S J; Hryn'ova, T; Idarraga, J; Johansen, M; Johns, K; Kalinowski, A; Khoriauli, G; Kirk, J; Klous, S; Kluge, E-E; Koeneke, K; Konoplich, R; Konstantinidis, N; Kwee, R; Landon, M; LeCompte, T; Ledroit, F; Lei, X; Lendermann, V; Lilley, J N; Losada, M; Maettig, S; Mahboubi, K; Mahout, G; Maltrana, D; Marino, C; Masik, J; Meier, K; Middleton, R P; Mincer, A; Moa, T; Monticelli, F; Moreno, D; Morris, J D; Mller, F; Navarro, G A; Negri, A; Nemethy, P; Neusiedl, A; Oltmann, B; Olvito, D; Osuna, C; Padilla, C; Panes, B; Parodi, F; Perera, V J O; Perez, E; Perez Reale, V; Petersen, B; Pinzon, G; Potter, C; Prieur, D P F; Prokishin, F; Qian, W; Quinonez, F; Rajagopalan, S; Reinsch, A; Rieke, S; Riu, I; Robertson, S; Rodriguez, D; Rogriquez, Y; Rhr, F; Saavedra, A; Sankey, D P C; Santamarina, C; Santamarina Rios, C; Scannicchio, D; Schiavi, C; Schmitt, K; Schultz-Coulon, H C; Schfer, U; Segura, E; Silverstein, D; Silverstein, S; Sivoklokov, S; Sjlin, J; Staley, R J; Stamen, R; Stelzer, J; Stockton, M C; Straessner, A; Strom, D; Sushkov, S; Sutton, M; Tamsett, M; Tan, C L A; Tapprogge, S; Thomas, J P; Thompson, P D; Torrence, E; Tripiana, M; Urquijo, P; Urrejola, P; Vachon, B; Vercesi, V; Vorwerk, V; Wang, M; Watkins, P M; Watson, A; Weber, P; Weidberg, T; Werner, P; Wessels, M; Wheeler-Ellis, S; Whiteson, D; Wiedenmann, W; Wielers, M; Wildt, M; Winklmeier, F; Wu, X; Xella, S; Zhao, L; Zobernig, H; de Seixas, J M; dos Anjos, A; Asman, B; Özcan, E

    2009-01-01

    The ATLAS experiment is preparing for data taking at 14 TeV collision energy. A rich discovery physics program is being prepared in addition to the detailed study of Standard Model processes which will be produced in abundance. The ATLAS multi-level trigger system is designed to accept one event in 2 105 to enable the selection of rare and unusual physics events. The ATLAS calorimeter system is a precise instrument, which includes liquid Argon electro-magnetic and hadronic components as well as a scintillator-tile hadronic calorimeter. All these components are used in the various levels of the trigger system. A wide physics coverage is ensured by inclusively selecting events with candidate electrons, photons, taus, jets or those with large missing transverse energy. The commissioning of the trigger system is being performed with cosmic ray events and by replaying simulated Monte Carlo events through the trigger and data acquisition system.

  15. Overview of the Defense Programs Research and Technology Development Program for fiscal year 1993. Appendix II research laboratories and facilities

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-30

    This document contains summaries of the research facilities that support the Defense Programs Research and Technology Development Program for FY 1993. The nine program elements are aggregated into three program clusters as follows: (1) Advanced materials sciences and technologies; chemistry and materials, explosives, special nuclear materials (SNM), and tritium. (2) Design sciences and advanced computation; physics, conceptual design and assessment, and computation and modeling. (3) Advanced manufacturing technologies and capabilities; system engineering science and technology, and electronics, photonics, sensors, and mechanical components. Section I gives a brief summary of 23 major defense program (DP) research and technology facilities and shows how these major facilities are organized by program elements. Section II gives a more detailed breakdown of the over 200 research and technology facilities being used at the Laboratories to support the Defense Programs mission.

  16. A general search for new phenomena at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Inst. for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania)]|[Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Inst. for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Inst., Moscow (RU)] (and others)

    2008-12-15

    A model-independent search for deviations from the Standard Model prediction is performed using the full e{sup {+-}}p data sample collected by the H1 experiment at HERA. All event topologies involving isolated electrons, photons, muons, neutrinos and jets with transverse momenta above 20 GeV are investigated in a single analysis. Events are assigned to exclusive classes according to their final state. A dedicated algorithm is used to search for deviations from the Standard Model in the distributions of the scalar sum of transverse momenta or the invariant mass of final state particles and to quantify their significance. Variables related to angular distributions and energy sharing between final state particles are also introduced to study the final state topologies. No significant deviation from the Standard Model expectation is observed in the phase space covered by this analysis. (orig.)

  17. Free-free absorption effects on Eddington luminosity

    CERN Document Server

    Ciotti, L

    2003-01-01

    In standard treatments the Eddington luminosity is calculated by assuming that the electron-photon cross section is well described by the Thomson cross section which is gray (frequency independent). Here we discuss some consequence of the introduction of free-free opacity in the Eddington luminosity computation: in particular, due to the dependence of free-free emission on the square of the gas density, it follows that the associated absorption cross section increases linearly with the gas density, so that in high density environments Eddington luminosity is correspondingly reduced. We present a summary of an ongoing exploration of the parameter space of the problem, and we conclude that Eddington luminosity in high density environments can be lowered by a factor of ten or more, making it considerably easier for black holes to accelerate and eject ambient gas.

  18. Atoms and Molecules in Cavities: From Weak to Strong Coupling in QED Chemistry

    CERN Document Server

    Flick, Johannes; Appel, Heiko; Rubio, Angel

    2016-01-01

    In this work, we provide an overview of how well-established concepts in the fields of quantum chemistry and material sciences have to be adapted when the quantum nature of light becomes important in correlated matter-photon problems. Therefore, we analyze model systems in optical cavities, where the matter-photon interaction is considered from the weak- to the strong coupling limit and for individual photon modes as well as for the multi-mode case. We identify fundamental changes in Born-Oppenheimer surfaces, spectroscopic quantities, conical intersections and efficiency for quantum control. We conclude by applying our novel recently developed quantum-electrodynamical density-functional theory to single-photon emission and show how a straightforward approximation accurately describes the correlated electron-photon dynamics. This paves the road to describe matter-photon interactions from first-principles and addresses the emergence of new states of matter in chemistry and material science.

  19. Strongly enhanced effects of Lorentz symmetry violation in entangled Yb+ ions

    CERN Document Server

    Dzuba, V A; Safronova, M S; Porsev, S G; Pruttivarasin, T; Hohensee, M A; Häffner, H

    2015-01-01

    Lorentz symmetry is one of the cornerstones of modern physics. However, a number of theories aiming at unifying gravity with the other fundamental interactions including string field theory suggest violation of Lorentz symmetry [1-4]. While the energy scale of such strongly Lorentz symmetry-violating physics is much higher than that currently attainable by particle accelerators, Lorentz violation may nevertheless be detectable via precision measurements at low energies [2]. Here, we carry out a systematic theoretical investigation of the sensitivity of a wide range of atomic systems to violation of local Lorentz invariance (LLI). Aim of these studies is to identify which atom shows the biggest promise to detect violation of Lorentz symmetry. We identify the Yb+ ion as an ideal system with high sensitivity as well as excellent experimental controllability. By applying quantum information inspired technology to Yb+, we expect tests of LLI violating physics in the electron-photon sector to reach levels of $10^{-...

  20. The molecular photo-cell: quantum transport and energy conversion at strong non-equilibrium.

    Science.gov (United States)

    Ajisaka, Shigeru; Žunkovič, Bojan; Dubi, Yonatan

    2015-02-09

    The molecular photo-cell is a single molecular donor-acceptor complex attached to electrodes and subject to external illumination. Besides the obvious relevance to molecular photo-voltaics, the molecular photo-cell is of interest being a paradigmatic example for a system that inherently operates in out-of-equilibrium conditions and typically far from the linear response regime. Moreover, this system includes electrons, phonons and photons, and environments which induce coherent and incoherent processes, making it a challenging system to address theoretically. Here, using an open quantum systems approach, we analyze the non-equilibrium transport properties and energy conversion performance of a molecular photo-cell, including both coherent and incoherent processes and treating electrons, photons, and phonons on an equal footing. We find that both the non-equilibrium conditions and decoherence play a crucial role in determining the performance of the photovoltaic conversion and the optimal energy configuration of the molecular system.

  1. Vacuum Polarization and Dynamical Chiral Symmetry Breaking: Phase Diagram of QED with Four-Fermion Contact Interaction

    CERN Document Server

    Akram, F; Gutierrez-Guerrero, L X; Masud, B; Rodriguez-Quintero, J; Calcaneo-Roldan, C; Tejeda-Yeomans, M E

    2012-01-01

    We study chiral symmetry breaking for fundamental charged fermions coupled electromagnetically to photons with the inclusion of four-fermion contact self-interaction term. We employ multiplicatively renormalizable models for the photon dressing function and the electron-photon vertex which minimally ensures mass anomalous dimension = 1. Vacuum polarization screens the interaction strength. Consequently, the pattern of dynamical mass generation for fermions is characterized by a critical number of massless fermion flavors above which chiral symmetry is restored. This effect is in diametrical opposition to the existence of criticality for the minimum interaction strength necessary to break chiral symmetry dynamically. The presence of virtual fermions dictates the nature of phase transition. Miransky scaling laws for the electromagnetic interaction strength and the four-fermion coupling, observed for quenched QED, are replaced by a mean-field power law behavior corresponding to a second order phase transition. T...

  2. Atoms and molecules in cavities, from weak to strong coupling in quantum-electrodynamics (QED) chemistry.

    Science.gov (United States)

    Flick, Johannes; Ruggenthaler, Michael; Appel, Heiko; Rubio, Angel

    2017-03-21

    In this work, we provide an overview of how well-established concepts in the fields of quantum chemistry and material sciences have to be adapted when the quantum nature of light becomes important in correlated matter-photon problems. We analyze model systems in optical cavities, where the matter-photon interaction is considered from the weak- to the strong-coupling limit and for individual photon modes as well as for the multimode case. We identify fundamental changes in Born-Oppenheimer surfaces, spectroscopic quantities, conical intersections, and efficiency for quantum control. We conclude by applying our recently developed quantum-electrodynamical density-functional theory to spontaneous emission and show how a straightforward approximation accurately describes the correlated electron-photon dynamics. This work paves the way to describe matter-photon interactions from first principles and addresses the emergence of new states of matter in chemistry and material science.

  3. A general search for new phenomena in ep scattering at HERA

    CERN Document Server

    Aktas, A; Anthonis, T; Asmone, A; Babaev, A; Backovic, S; Bähr, J; Baranov, P; Barrelet, E; Bartel, Wulfrin; Baumgartner, S; Becker, J; Beckingham, M; Behnke, O; Behrendt, O; Belousov, A; Berger, C; Berger, N; Berndt, T; Bizot, J C; Böhme, J; Boenig, M O; Boudry, V; Bracinik, J; Brisson, V; Broker, H B; Brown, D P; Bruncko, Dusan; Büsser, F W; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Caron, S; Cassol-Brunner, F; Cerny, K; Chekelian, V; Contreras, J G; Coppens, Y R; Coughlan, J A; Cox, B E; Cozzika, G; Cvach, J; Dainton, J B; Dau, W D; Daum, K; Delcourt, B; Demirchyan, R; de Roeck, A; Desch, Klaus; De Wolf, E A; Diaconu, C; Dingfelder, J; Dodonov, V; Dubak, A; Duprel, C; Eckerlin, G; Efremenko, V; Egli, S; Eichler, R; Eisele, F; Ellerbrock, M; Elsen, E; Erdmann, M; Erdmann, W; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Ferencei, J; Fleischer, M; Fleischmann, P; Fleming, Y H; Flucke, G; Flügge, G; Fomenko, A; Foresti, I; Formánek, J; Franke, G; Frising, G; Gabathuler, Erwin; Gabathuler, K; Garutti, E; Garvey, J; Gayler, J; Gerhards, R; Gerlich, C; Ghazaryan, S; Ginzburgskaya, S; Görlich, L; Gogitidze, N; Gorbounov, S; Grab, C; Grässler, Herbert; Greenshaw, T; Gregori, M; Grindhammer, G; Gwilliam, C; Haidt, D; Hajduk, L; Haller, J; Hansson, M; Heinzelmann, G; Henderson, R C W; Henschel, H; Henshaw, O; Herrera-Corral, G; Herynek, I; Heuer, R D; Hildebrandt, M; Hiller, K H; Hoting, P; Hoffmann, D; Horisberger, R P; Hovhannisyan, A; Ibbotson, M; Ismail, M; Jacquet, M; Janauschek, L; Janssen, X; Jemanov, V; Jönsson, L B; Johnson, D P; Jung, H; Kant, D; Kapichine, M; Karlsson, M; Katzy, J; Keller, N; Kennedy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Klimkovich, T; Kluge, T; Knies, G; Knutsson, A; Koblitz, B; Korbel, V; Kostka, P; Koutouev, R; Kropivnitskaya, A; Kroseberg, J; Krüger, K; Kuckens, J; Kuhr, T; Landon, M P J; Lange, W; Lastoviicka, T; Laycock, P; Lebedev, A; Leiner, B; Lemrani, R; Lendermann, V; Levonian, S; Lindfeld, L; Lipka, K; List, B; Lobodzinska, E; Loktionova, N A; López-Fernandez, R; Lubimov, V; Lüders, H; Lüke, D; Lux, T; Lytkin, L; Makankine, A; Malden, N; Malinovskii, E I; Mangano, S; Marage, P; Marks, J; Marshall, R; Martisikova, M; Martyn, H U; Maxfield, S J; Meer, D; Mehta, A; Meier, K; Meyer, A B; Meyer, H; Meyer, J; Mikocki, S; Milcewicz-Mika, I; Milstead, D; Mohamed, A; Moreau, F; Morozov, A; Morozov, I; Morris, J V; Mozer, M U; Müller, K; Murn, P; Nagovizin, V; Nankov, K; Naroska, Beate; Naumann, J; Naumann, T; Newman, P R; Niebuhr, C B; Nikiforov, A; Nikitin, D K; Nowak, G; Nozicka, M; Oganezov, R; Olivier, B; Olsson, J E; Ossoskov, G; Ozerov, D; Paramonov, A A; Pascaud, C; Patel, G D; Peez, M; Pérez, E; Perieanu, A; Petrukhin, A; Pitzl, D; Placakyte, R; Pöschl, R; Portheault, B; Povh, B; Raicevic, N; Reimer, P; Reisert, B; Rimmer, A; Risler, C; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A A; Rurikova, Z; Rusakov, S V; Rybicki, K; Sankey, D P C; Sauvan, E; Schatzel, S; Scheins, J; Schilling, F P; Schleper, P; Schmidt, S; Schmitt, S; Schneider, M; Schoeffel, L; Schöning, A; Schröder, V; Schultz-Coulon, H C; Schwanenberger, C; Sedlak, K; Sefkow, F; Shevyakov, I; Shtarkov, L N; Sirois, Y; Sloan, T; Smirnov, P; Soloviev, Yu; South, D; Spaskov, V; Specka, A; Spitzer, H; Stamen, R; Stella, B; Stiewe, J; Strauch, I; Straumann, U; Tchoulakov, V; Thompson, G; Thompson, P D; Tomasz, F; Traynor, D; Truöl, P; Tsipolitis, G; Tsurin, I; Turnau, J; Tzamariudaki, E; Uraev, A; Urban, M; Usik, A; Utkin, D; Valkárová, A; Vallée, C; Van Mechelen, P; Van Remortel, N; Vargas, A; Trevino; Vazdik, Ya A; Veelken, C; Vest, A; Vinokurova, S; Volchinski, V; Wacker, K; Wagner, J; Weber, G; Weber, R; Wegener, D; Werner, C; Werner, N; Wessels, M; Wessling, B; Winter, G G; Wissing, C; Woerling, E E; Wolf, R; Wünsch, E; Xella, S M; Yan, W; Yeganov, V; Zaicek, J; Zaleisak, J; Zhang, Z; Zhelezov, A; Zhokin, A; Zohrabyan, H G; Zomer, F

    2004-01-01

    A model-independent search for deviations from the Standard Model prediction is performed in e^+ p and e^- p collisions at HERA using H1 data corresponding to an integrated luminosity of 117 pb^-1. For the first time all event topologies involving isolated electrons, photons, muons, neutrinos and jets with high transverse momenta are investigated in a single analysis. Events are assigned to exclusive classes according to their final state. A statistical algorithm is developed to search for deviations from the Standard Model in the distributions of the scalar sum of transverse momenta or invariant mass of final state particles and to quantify their significance. A good agreement with the Standard Model prediction is observed in most of the event classes. The most significant deviation is found for a topology containing an isolated muon, missing transverse momentum and a jet, consistent with a previously reported observation.

  4. A General Search for New Phenomena at HERA

    CERN Document Server

    Aaron, F D; Andreev, V; Antunovic, B; Aplin, S; Asmone, A; Astvatsatourov, A; Backovic, S; Baghdasaryan, A; Barrelet, E; Bartel, W; Begzsuren, K; Behnke, O; Belousov, A; Bizot, J C; Boudry, V; Bozovic-Jelisavcic, I; Bracinik, J; Brandt, G; Brinkmann, M; Brisson, V; Bruncko, D; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Cantun Avila, K B; Cassol-Brunner, F; Cerny, K; Cerny, V; Chekelian, V; Cholewa, A; Contreras, J G; Coughlan, J A; Cozzika, G; Cvach, J; Dainton, J B; Daum, K; Deak, M; de Boer, Y; Delcourt, B; Del Degan, M; Delvax, J; De Roeck, A; De Wolf, E A; Diaconu, C; Dodonov, V; Dossanov, A; Dubak, A; Eckerlin, G; Efremenko, V; Egli, S; Eliseev, A; Elsen, E; Falkiewicz, A; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Fischer, D J; Fleischer, M; Fomenko, A; Gabathuler, E; Gayler, J; Ghazaryan, S; Glazov, A; Glushkov, I; Goerlich, L; Gogitidze, N; Gouzevitch, M; Grab, C; Greenshaw, T; Grell, B R; Grindhammer, G; Habib, S; Haidt, D; Hansson, M; Helebrant, C; Henderson, R C W; Hennekemper, E; Henschel, H; Herbst, M; Herrera, G; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R; Hreus, T; Jacquet, M; Janssen, M E; Janssen, X; Jemanov, V; Jonsson, L; Jung, Andreas Werner; Jung, H; Kapichine, M; Katzy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Kluge, T; Knutsson, A; Kogler, R; Korbel, V; Kostka, P; Kraemer, M; Krastev, K; Kretzschmar, J; Kropivnitskaya, A; Kruger, K; Kutak, K; Landon, M P J; Lange, W; Lastovicka-Medin, G; Laycock, P; Lebedev, A; Leibenguth, G; Lendermann, V; Levonian, S; Li, G; Lipka, K; Liptaj, A; List, B; List, J; Loktionova, N; Lopez-Fernandez, R; Lubimov, V; Lytkin, L; Makankine, A; Malinovski, E; Marage, P; Marti, Ll; Martyn, H U; Maxfield, S J; Mehta, A; Meier, K; Meyer, A B; Meyer, H; Meyer, H; Meyer, J; Michels, V; Mikocki, S; Milcewicz-Mika, I; Moreau, F; Morozov, A; Morris, J V; Mozer, Matthias Ulrich; Mudrinic, M; Muller, K; Murin, P; Naroska, B; Naumann, Th; Newman, P R; Niebuhr, C; Nikiforov, A; Nowak, G; Nowak, K; Nozicka, M; Olivier, B; Olsson, J E; Osman, S; Ozerov, D; Palichik, V; Panagoulias, I; Pandurovic, M; Papadopoulou, Th; Pascaud, C; Patel, G D; Pejchal, O; Perez, E; Petrukhin, A; Picuric, I; Piec, S; Pitzl, D; Placakyte, R; Polifka, R; Povh, B; Preda, T; Radescu, V; Rahmat, A J; Raicevic, N; Raspiareza, A; Ravdandorj, T; Reimer, P; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rotaru, M; Ruiz Tabasco, J E; Rurikova, Z; Rusakov, S; Salek, D; Sankey, D P C; Sauter, M; Sauvan, E; Schmitt, S; Schmitz, C; Schoeffel, L; Schoning, A; Schultz-Coulon, H C; Sefkow, F; Shaw-West, R N; Sheviakov, I; Shtarkov, L N; Shushkevich, S; Sloan, T; Smiljanic, Ivan; Soloviev, Y; Sopicki, P; South, D; Spaskov, V; Specka, Arnd E; Staykova, Z; Steder, M; Stella, B; Stoicea, G; Straumann, U; Sunar, D; Sykora, T; Tchoulakov, V; Thompson, G; Thompson, P D; Toll, T; Tomasz, F; Tran, T H; Traynor, D; Trinh, T N; Truol, P; Tsakov, I; Tseepeldorj, B; Turnau, J; Urban, K; Valkarova, A; Vallee, C; Van Mechelen, P; Vargas Trevino, A; Vazdik, Y; Vinokurova, S; Volchinski, V; von den Driesch, M; Wegener, D; Wessels, M; Wissing, Ch; Wunsch, E; Zacek, J; Zalesak, J; Zhang, Z; Zhokin, A; Zimmermann, T; Zohrabyan, H; Zomer, F

    2009-01-01

    A model--independent search for deviations from the Standard Model prediction is performed using the full $e^\\pm p$ data sample collected by the H1 experiment at HERA. All event topologies involving isolated electrons, photons, muons, neutrinos and jets with transverse momenta above 20 GeV are investigated in a single analysis. Events are assigned to exclusive classes according to their final state. A dedicated algorithm is used to search for deviations from the Standard Model in the distributions of the scalar sum of transverse momenta or the invariant mass of final state particles and to quantify their significance. Variables related to angular distributions and energy sharing between final state particles are also introduced to study the final state topologies. No significant deviation from the Standard Model expectation is observed in the phase space covered by this analysis.

  5. MUSiC A General Search for Deviations from Monte Carlo Predictions in CMS

    CERN Document Server

    Biallass, Philipp

    2009-01-01

    A model independent analysis approach in CMS is presented, systematically scanning the data for deviations from the Monte Carlo expectation. Such an analysis can contribute to the understanding of the detector and the tuning of the event generators. Furthermore, due to the minimal theoretical bias this approach is sensitive to a variety of models of new physics, including those not yet thought of. Events are classified into event classes according to their particle content (muons, electrons, photons, jets and missing transverse energy). A broad scan of various distributions is performed, identifying significant deviations from the Monte Carlo simulation. The importance of systematic uncertainties is outlined, which are taken into account rigorously within the algorithm. Possible detector effects and generator issues, as well as models involving Supersymmetry and new heavy gauge bosons are used as an input to the search algorithm.

  6. MUSIC -- An Automated Scan for Deviations between Data and Monte Carlo Simulation

    CERN Document Server

    CMS Collaboration

    We present a model independent analysis approach, systematically scanning the data for deviations from the Monte Carlo expectation. Such an analysis can contribute to the understanding of the detector and the tuning of the event generators. Due to the minimal theoretical bias this approach is sensitive to a variety of models, including those not yet thought of. Events are classified into event classes according to their particle content (muons, electrons, photons, jets and missing transverse energy). A broad scan of various distributions is performed, identifying significant deviations from the Monte Carlo simulation. We outline the importance of systematic uncertainties, which are taken into account rigorously within the algorithm. Possible detector effects and generator issues, as well as models involving supersymmetry and new heavy gauge bosons have been used as an input to the search algorithm. %Several models involving supersymmetry, new heavy gauge bosons and leptoquarks, as well as possible detector ef...

  7. MUSiC - A general search for deviations from monte carlo predictions in CMS

    Science.gov (United States)

    Biallass, Philipp A.; CMS Collaboration

    2009-06-01

    A model independent analysis approach in CMS is presented, systematically scanning the data for deviations from the Monte Carlo expectation. Such an analysis can contribute to the understanding of the detector and the tuning of the event generators. Furthermore, due to the minimal theoretical bias this approach is sensitive to a variety of models of new physics, including those not yet thought of. Events are classified into event classes according to their particle content (muons, electrons, photons, jets and missing transverse energy). A broad scan of various distributions is performed, identifying significant deviations from the Monte Carlo simulation. The importance of systematic uncertainties is outlined, which are taken into account rigorously within the algorithm. Possible detector effects and generator issues, as well as models involving Supersymmetry and new heavy gauge bosons are used as an input to the search algorithm.

  8. MUSiC - A Generic Search for Deviations from Monte Carlo Predictions in CMS

    Science.gov (United States)

    Hof, Carsten

    2009-05-01

    We present a model independent analysis approach, systematically scanning the data for deviations from the Standard Model Monte Carlo expectation. Such an analysis can contribute to the understanding of the CMS detector and the tuning of the event generators. Furthermore, due to the minimal theoretical bias this approach is sensitive to a variety of models of new physics, including those not yet thought of. Events are classified into event classes according to their particle content (muons, electrons, photons, jets and missing transverse energy). A broad scan of various distributions is performed, identifying significant deviations from the Monte Carlo simulation. We outline the importance of systematic uncertainties, which are taken into account rigorously within the algorithm. Possible detector effects and generator issues, as well as models involving supersymmetry and new heavy gauge bosons have been used as an input to the search algorithm.

  9. ATLAS level-1 jet trigger rates and study of the ATLAS discovery potential of the neutral MSSM Higgs bosons in b-jet decay channels

    CERN Document Server

    Mahboubi, Kambiz

    2001-01-01

    The response of the ATLAS calorimeters to electrons, photons and hadrons, in terms of the longitudinal and lateral shower development, is parameterized using the GEANT package and a detailed detector description (DICE). The parameterizations are implemented in the ATLAS Level-1 (LVL1) Calorimeter Trigger fast simulation package which, based on an average detector geometry, simulates the complete chain of the LVL1 calorimeter trigger system. In addition, pile-up effects due to multiple primary interactions are implemented taking into account the shape and time history of the trigger signals. An interface to the fast physics simulation package (ATLFAST) is also developed in order to perform ATLAS physics analysis, including the LVL1 trigger effects, in a consistent way. The simulation tools, the details of the parameterization and the interface are described. The LVL1 jet trigger thresholds corresponding to the current trigger menus are determined within the framework of the fast simulation, and the LVL1 jet tr...

  10. Elucidating Quantum Confinement in Graphene Oxide Dots Based On Excitation-Wavelength-Independent Photoluminescence.

    Science.gov (United States)

    Yeh, Te-Fu; Huang, Wei-Lun; Chung, Chung-Jen; Chiang, I-Ting; Chen, Liang-Che; Chang, Hsin-Yu; Su, Wu-Chou; Cheng, Ching; Chen, Shean-Jen; Teng, Hsisheng

    2016-06-02

    Investigating quantum confinement in graphene under ambient conditions remains a challenge. In this study, we present graphene oxide quantum dots (GOQDs) that show excitation-wavelength-independent photoluminescence. The luminescence color varies from orange-red to blue as the GOQD size is reduced from 8 to 1 nm. The photoluminescence of each GOQD specimen is associated with electron transitions from the antibonding π (π*) to oxygen nonbonding (n-state) orbitals. The observed quantum confinement is ascribed to a size change in the sp(2) domains, which leads to a change in the π*-π gap; the n-state levels remain unaffected by the size change. The electronic properties and mechanisms involved in quantum-confined photoluminescence can serve as the foundation for the application of oxygenated graphene in electronics, photonics, and biology.

  11. The transverse shape of the electron

    CERN Document Server

    Hoyer, Paul

    2009-01-01

    We study the charge density, form factors and spin distributions of the electron induced by its |e \\gamma> light-front Fock state in impact parameter space. Only transversally compact Fock states contribute to the leading behavior of the Dirac and Pauli form factors as the momentum transfer tends to infinity. Power suppressed contributions are not compact, and distributions weighted by the transverse size have end-point contributions. The Fock state conserves the spin of the parent electron locally, but the separate contributions of the electron, photon and orbital angular momentum depend on longitudinal momentum and impact parameter. The sign of the anomalous magnetic moment of the electron may be understood intuitively from the density distribution, addressing a challenge by Feynman.

  12. Design of monolithically integrated GeSi electro-absorption modulators and photodetectors on a SOI platform

    Science.gov (United States)

    Liu, Jifeng; Pan, Dong; Jongthammanurak, Samerkhae; Wada, Kazumi; Kimerling, Lionel C.; Michel, Jurgen

    2007-01-01

    We present a design of monolithically integrated GeSi electroabsorption modulators and photodetectors for electronic-photonic integrated circuits on a silicon-on-insulator (SOI) platform. The GeSi electroabsorption modulator is based on the Franz-Keldysh effect, and the GeSi composition is chosen for optimal performance around 1550 nm. The designed modulator device is butt-coupled to Si(core)/SiO2(cladding) high index contrast waveguides, and has a predicted 3 dB bandwidth of >50 GHz and an extinction ratio of 10 dB. The same device structure can also be used for a waveguide-coupled photodetector with a predicted responsivity of > 1 A/W and a 3 dB bandwidth of > 35 GHz. Use of the same GeSi composition and device structure allows efficient monolithic process integration of the modulators and the photodetectors on an SOI platform.

  13. Fluorescence of colloidal PbSe/PbS QDs in NIR luminescent solar concentrators.

    Science.gov (United States)

    Aeberhard, Urs; Vaxenburg, Roman; Lifshitz, Efrat; Tomić, Stanko

    2012-12-21

    For applications in luminescent solar concentrators harvesting subgap photons, either via direct irradiation of solar cells with optimized band gap or via sensitization of an up-conversion process, exact knowledge and tunability of both the spectral shape and the intensity of the emission are of paramount importance. In this work, we investigate theoretically the photoluminescence spectra of colloidal core-shell PbSe/PbS QDs with type II alignments in the valence band. The method builds on a steady-state formulation of the non-equilibrium Greens function theory for a microscopic system of coupled electrons, photons and phonons interfaced with electronic structure calculations based on a k·p model for PbSe/PbS core-shell QDs. The resulting output spectral density of photons in a realistic QD ensemble is obtained via the renormalization of the incident spectrum according to the polarization of the system.

  14. Circular dichroism, magnetic knots and the spectropolarimetry of the Cosmic Microwave Background

    CERN Document Server

    Giovannini, Massimo

    2010-01-01

    When the last electron-photon scattering takes place in a magnetized environment, the degree of circular polarization of the outgoing radiation depends upon the magnetic field strength. After deriving the scattering matrix of the process, the generalized radiative transfer equations are deduced in the presence of the relativistic fluctuations of the geometry and for all the four brightness perturbations. The new system of equations is solved under the assumption that the incident radiation is not polarized. The induced V-mode polarization is analyzed both analytically and numerically. The corresponding angular power spectra are calculated and compared with the measured (or purported) values of the linear polarizations (i.e. E-mode and B-mode) as they arise in the concordance model and in its neighboring extensions. Possible connections between the V-mode polarization of the Cosmic Microwave background and the topological properties of the magnetic flux lines prior to equality are outlined and briefly explored...

  15. Soft lithography for micro- and nanoscale patterning.

    Science.gov (United States)

    Qin, Dong; Xia, Younan; Whitesides, George M

    2010-03-01

    This protocol provides an introduction to soft lithography--a collection of techniques based on printing, molding and embossing with an elastomeric stamp. Soft lithography provides access to three-dimensional and curved structures, tolerates a wide variety of materials, generates well-defined and controllable surface chemistries, and is generally compatible with biological applications. It is also low in cost, experimentally convenient and has emerged as a technology useful for a number of applications that include cell biology, microfluidics, lab-on-a-chip, microelectromechanical systems and flexible electronics/photonics. As examples, here we focus on three of the commonly used soft lithographic techniques: (i) microcontact printing of alkanethiols and proteins on gold-coated and glass substrates; (ii) replica molding for fabrication of microfluidic devices in poly(dimethyl siloxane), and of nanostructures in polyurethane or epoxy; and (iii) solvent-assisted micromolding of nanostructures in poly(methyl methacrylate).

  16. Self-Consistent Fokker-Planck Treatment Of Particle Distributions in Astrophysical Plasmas

    CERN Document Server

    Nayakshin, S; Nayakshin, Sergei; Melia, Fulvio

    1997-01-01

    High-energy, multi-component plasmas in which pair creation and annihilation, lepton-lepton scattering, lepton-proton scattering, and Comptonization all contribute to establishing the particle and photon distributions, are present in a broad range of compact astrophysical objects. Earlier work has included much of the microphysics needed to account for electron-photon and electron-proton interactions, but little has been done to handle the redistribution of the particles as a result of their Coulomb interaction with themselves in an arbitrary case. Our goal here is to use a Fokker-Planck approach in order to develop a fully self-consistent theory for the interaction of arbitrarily distributed particles and radiation to arrive at an accurate representation of the high-energy plasma in these sources. We conduct several tests representative of two dominant segments of parameter space and discuss physical implications of the non-Maxwellian distribution function. Approximate analytical forms for the electron distr...

  17. Reverse current reduction of Ge photodiodes on Si without post-growth annealing Invited Paper

    Institute of Scientific and Technical Information of China (English)

    Sungbong Park; Shinya Takita; Yasuhiko; Ishikawa; Jiro Osaka; Kazumi Wada

    2009-01-01

    A new approach to reduce the reverse current of Ge pin photodiodes on Si is presented, in which an i-Si layer is inserted between Ge and top Si layers to reduce the electric field in the Ge layer. Without post- growth annealing, the reverse current density is reduced to ~10 mA/cm2 at -1 V, i.e., over one order of magnitude lower than that of the reference photodiode without i-Si layer. However, the responsivity of the photodiodes is not severely compromised. This lowered-reverse-current is explained by band-pinning at the i-Si/i-Ge interface. Barrier lowering mechanism induced by E-field is also discussed. The presented "non-thermal" approach to reduce reverse current should accelerate electronics-photonics convergence by using Ge on the Si complementary metal oxide semiconductor (CMOS) platform.

  18. CMS Level—1 Regional Calorimeter Trigger System

    Institute of Scientific and Technical Information of China (English)

    P.Chumney; S.Dasu; 等

    2001-01-01

    The CMS regional calorimeter trigger system detects signatures of electrons/photons,taus,jets,and missing and total transverse energy in a deadtinmess pipelined architecture .This system receives 7000 calorimeter tregger tower energies on 1.2 Gband digital copper cable serial links and processes them in a low-latency pipelined design using custom-built electronics.At the heart of the system is the Receiver Card which uses the new generation of gigabit ethernet receiver chips on a mezzanine card to convert serial data to parallel data before transmission on a 160 MHz backplane for further processing by cards that sum energies and identify electrons and jets.We describe the algorithms and hardware implementation,and summarize the simulation results that show that this system is capable of handling the rate requirements while triggering on physics signals with high efficiency.

  19. Status of the Atlas Calorimeters: their performance after two years of LHC operation and plans for future upgrades

    CERN Document Server

    Solans, CA; The ATLAS collaboration

    2012-01-01

    The ATLAS experiment is designed to study the proton-proton collisions produced at the Large Hadron Collider (LHC) at CERN. Its calorimeter system measures the energy and direction of final state particles with pseudo rapidity $|eta| < 4.9$. Accurate identification and measurement of the characteristics of electromagnetic objects (electrons/photons) are performed by liquid argon (LAr)-lead sampling calorimeters in the region $|eta| < 3.2$, using an innovative accordion geometry that provides a fast, uniform azimuthal response without gaps. The hadronic calorimeters measure the properties of hadrons, jets, and tau leptons, and also contribute to the measurement of the missing transverse energy and identification of muons. This is done in the region $|eta| < 1.7$ with a scintillator-steel sampling calorimeter, and in the region $1.4 < |eta| < 3.2$ with a copper-LAr sampling calorimeter. The coverage is extended to $|eta| < 4.9$ by an integrated forward calorimeter (FCal...

  20. LHCb: First year of running for the LHCb calorimeter system

    CERN Multimedia

    Guz, Y

    2011-01-01

    The LHCb experiment is dedicated to precision measurements of CP violation and rare decays of B hadrons at the Large Hadron Collider (LHC) at CERN (Geneva) [1, 2]. LHCb is a single-arm spectrometer with a forward angular coverage from approximately 10 mrad to 300 mrad. It comprises a calorimeter system composed of four subdetectors [3]. It selects transverse energy hadron, electron and photon candidates for the first trigger level (L0), which makes a decision 4µs after the interaction. It provides the identification of electrons, photons and hadrons as well as the measurement of their energies and positions. The set of constraints resulting from these functionalities defines the general structure and the main characteristics of the calorimeter system and its associated electronics. A classical structure of an electromagnetic calorimeter (ECAL) followed by a hadron calorimeter (HCAL) has been adopted. In addition the system includes in front of them the Scintillating Pad Detector (SPD) and Pre-Showe...

  1. The time-dependent one-zone hadronic model - First principles

    CERN Document Server

    Dimitrakoudis, S; Protheroe, R J; Reimer, A

    2012-01-01

    We present a time-dependent approach to the one-zone hadronic model in the case where the photon spectrum is produced by ultrarelativistic protons interacting with soft photons that are produced from protons and low magnetic fields. Assuming that protons are injected at a certain rate in a homogeneous spherical volume containing a magnetic field, the evolution of the system can be described by five coupled kinetic equations, for protons, electrons, photons, neutrons, and neutrinos. Photopair and photopion interactions are modelled using the results of Monte-Carlo simulations and, in particular from the SOPHIA code for the latter. The coupling of energy losses and injection introduces a self-consistency in our approach and allows the study of the comparative relevancy of processes at various conditions, the efficiency of the conversion of proton luminosity to radiation, the resulting neutrino spectra, and the effects of time variability on proton injection, among other topics. We present some characteristic ex...

  2. Quantum materials. Lateral semiconductor nanostructures, hybrid systems and nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Heitmann, Detlef (ed.) [Hamburg Univ. (Germany). Inst. fuer Angewandte Physik

    2010-07-01

    Semiconductor nanostructures are ideal systems to tailor the physical properties via quantum effects, utilizing special growth techniques, self-assembling, wet chemical processes or lithographic tools in combination with tuneable external electric and magnetic fields. Such systems are called ''Quantum Materials''.The electronic, photonic, and phononic properties of these systems are governed by size quantization and discrete energy levels. The charging is controlled by the Coulomb blockade. The spin can be manipulated by the geometrical structure, external gates and by integrating hybrid ferromagnetic emitters.This book reviews sophisticated preparation methods for quantum materials based on III-V and II-VI semiconductors and a wide variety of experimental techniques for the investigation of these interesting systems. It highlights selected experiments and theoretical concepts and gives such a state-of-the-art overview about the wide field of physics and chemistry that can be studied in these systems. (orig.)

  3. Optical Slot-Waveguide Based Biochemical Sensors

    Directory of Open Access Journals (Sweden)

    Carlos Angulo Barrios

    2009-06-01

    Full Text Available Slot-waveguides allow light to be guided and strongly confined inside a nanometer-scale region of low refractive index. Thus stronger light-analyte interaction can be obtained as compared to that achievable by a conventional waveguide, in which the propagating beam is confined to the high-refractive-index core of the waveguide. In addition, slot-waveguides can be fabricated by employing CMOS compatible materials and technology, enabling miniaturization, integration with electronic, photonic and fluidic components in a chip, and mass production. These advantages have made the use of slot-waveguides for highly sensitive biochemical optical integrated sensors an emerging field. In this paper, recent achievements in slot-waveguide based biochemical sensing will be reviewed. These include slot-waveguide ring resonator based refractometric label-free biosensors, label-based optical sensing, and nano-opto-mechanical sensors.

  4. Overview of the LHCb Calorimeter Detectors

    CERN Document Server

    Perret, P

    2013-01-01

    The LHCb calorimeter system is composed of four subdetectors: an electromagnetic calorimeter (ECAL) followed by a hadron calorimeter (HCAL). In addition the system includes in front of them the Scintillating Pad Detector (SPD) and Pre-Shower (PS). It is used to select transverse energy hadron, electron and photon candidates for the first trigger level and it provides the identification of electrons, photons and hadrons as well as the measurement of their energies and positions. The design and construction characteristics of the LHCb calorimeter will be recalled. Strategies for monitoring and calibration during data taking will be detailed in all aspects. Scintillating fibres, plastics and photomultipliers suffer from ageing due to radiation damage or high currents. Different methods which are used to calibrate the detectors and to recover the initial performances will be presented. The performances achieved will be illustrated in selected channels of interest for B physics.

  5. Nanomaterials for optical data storage

    Science.gov (United States)

    Gu, Min; Zhang, Qiming; Lamon, Simone

    2016-12-01

    The growing amount of data that is generated every year creates an urgent need for new and improved data storage methods. Nanomaterials, which have unique mechanical, electronic and optical properties owing to the strong confinement of electrons, photons and phonons at the nanoscale, are enabling the development of disruptive methods for optical data storage with ultra-high capacity, ultra-long lifetime and ultra-low energy consumption. In this Review, we survey recent advancements in nanomaterials technology towards the next generation of optical data storage systems, focusing on metallic nanoparticles, graphene and graphene oxide, semiconductor quantum dots and rare-earth-doped nanocrystals. We conclude by discussing the use of nanomaterials in data storage systems that do not rely on optical mechanisms and by surveying the future prospects for the field.

  6. Application of egs4 computer code for determination of gamma ray spectrum and dose rate distribution in gammacell 220

    Science.gov (United States)

    Raisali, G. R.; Sohrabpour, M.

    1993-10-01

    The EGS4 a Monte Carlo electron-photon transport simulation package together with a locally developed computer program "GCELL" has been used to simulate the transport of the gamma rays in Gammacell 220. An additional lead attenuator has been inserted in the chamber, has been included for those cases where lower dose rates were required. For three cases of 0, 1.35 and 4.0 cm thickness of added lead attenuators, the gamma spectrum, and dose rate distribution inside the chamber have been determined. For the case of no attenuator present, the main shield around the source cage has been included in the simulation program and its albedo effects have been investigated. The calculated dose rate distribution in the Gammacell chamber has been compared against measurements carried out with Fricke, PMMA and Gafchromic film dosimeters.

  7. Analysis of Pyramidal Surface Texturization of Silicon Solar Cells by Molecular Dynamics Simulations

    Directory of Open Access Journals (Sweden)

    Hsiao-Yen Chung

    2008-01-01

    Full Text Available The purpose of this paper is to explore the relations between surface texturization and absorptance of multicrystalline silicon solar cells by a simple new model, based on the classic molecular (MD dynamics simulation, alternative to complex electron-photon interactions to analyze the surface texturization of solar cells. In this study, the large tilted angle leads to the lower efficiency of solar cell. To consider the effect of incident angle, a range of high efficiency exists due to the increasing probability of second reflection. Furthermore, the azimuth angle of incident light also affects the efficiency of solar cells. Our results agree well with previous studies. This MD model can potentially be used to predict the efficiency promotion in any optical reflection-absorption cases.

  8. MUSiC - A general search for deviations from Monte Carlo predictions in CMS

    Energy Technology Data Exchange (ETDEWEB)

    Biallass, Philipp A, E-mail: biallass@cern.c [Physics Institute IIIA, RWTH Aachen, Physikzentrum, 52056 Aachen (Germany)

    2009-06-01

    A model independent analysis approach in CMS is presented, systematically scanning the data for deviations from the Monte Carlo expectation. Such an analysis can contribute to the understanding of the detector and the tuning of the event generators. Furthermore, due to the minimal theoretical bias this approach is sensitive to a variety of models of new physics, including those not yet thought of. Events are classified into event classes according to their particle content (muons, electrons, photons, jets and missing transverse energy). A broad scan of various distributions is performed, identifying significant deviations from the Monte Carlo simulation. The importance of systematic uncertainties is outlined, which are taken into account rigorously within the algorithm. Possible detector effects and generator issues, as well as models involving Supersymmetry and new heavy gauge bosons are used as an input to the search algorithm.

  9. WE-AB-204-11: Development of a Nuclear Medicine Dosimetry Module for the GPU-Based Monte Carlo Code ARCHER

    Energy Technology Data Exchange (ETDEWEB)

    Liu, T; Lin, H; Xu, X [Rensselaer Polytechnic Institute, Troy, NY (United States); Stabin, M [Vanderbilt Univ Medical Ctr, Nashville, TN (United States)

    2015-06-15

    Purpose: To develop a nuclear medicine dosimetry module for the GPU-based Monte Carlo code ARCHER. Methods: We have developed a nuclear medicine dosimetry module for the fast Monte Carlo code ARCHER. The coupled electron-photon Monte Carlo transport kernel included in ARCHER is built upon the Dose Planning Method code (DPM). The developed module manages the radioactive decay simulation by consecutively tracking several types of radiation on a per disintegration basis using the statistical sampling method. Optimization techniques such as persistent threads and prefetching are studied and implemented. The developed module is verified against the VIDA code, which is based on Geant4 toolkit and has previously been verified against OLINDA/EXM. A voxelized geometry is used in the preliminary test: a sphere made of ICRP soft tissue is surrounded by a box filled with water. Uniform activity distribution of I-131 is assumed in the sphere. Results: The self-absorption dose factors (mGy/MBqs) of the sphere with varying diameters are calculated by ARCHER and VIDA respectively. ARCHER’s result is in agreement with VIDA’s that are obtained from a previous publication. VIDA takes hours of CPU time to finish the computation, while it takes ARCHER 4.31 seconds for the 12.4-cm uniform activity sphere case. For a fairer CPU-GPU comparison, more effort will be made to eliminate the algorithmic differences. Conclusion: The coupled electron-photon Monte Carlo code ARCHER has been extended to radioactive decay simulation for nuclear medicine dosimetry. The developed code exhibits good performance in our preliminary test. The GPU-based Monte Carlo code is developed with grant support from the National Institute of Biomedical Imaging and Bioengineering through an R01 grant (R01EB015478)

  10. Combined photon-electron beams in the treatment of the supraclavicular lymph nodes in breast cancer: A novel technique that achieves adequate coverage while reducing lung dose.

    Science.gov (United States)

    Salem, Ahmed; Mohamad, Issa; Dayyat, Abdulmajeed; Kanaa'n, Haitham; Sarhan, Nasim; Roujob, Ibrahim; Salem, Abdel-Fattah; Afifi, Shatha; Jaradat, Imad; Mubiden, Rasmi; Almousa, Abdelateif

    2015-01-01

    Radiation pneumonitis is a well-documented side effect of radiation therapy for breast cancer. The purpose of this study was to compare combined photon-electron, photon-only, and electron-only plans in the radiation treatment of the supraclavicular lymph nodes. In total, 13 patients requiring chest wall and supraclavicular nodal irradiation were planned retrospectively using combined photon-electron, photon-only, and electron-only supraclavicular beams. A dose of 50Gy over 25 fractions was prescribed. Chest wall irradiation parameters were fixed for all plans. The goal of this planning effort was to cover 95% of the supraclavicular clinical target volume (CTV) with 95% of the prescribed dose and to minimize the volume receiving ≥ 105% of the dose. Comparative end points were supraclavicular CTV coverage (volume covered by the 95% isodose line), hotspot volume, maximum radiation dose, contralateral breast dose, mean total lung dose, total lung volume percentage receiving at least 20 Gy (V(20 Gy)), heart volume percentage receiving at least 25 Gy (V(25 Gy)). Electron and photon energies ranged from 8 to 18 MeV and 4 to 6 MV, respectively. The ratio of photon-to-electron fractions in combined beams ranged from 5:20 to 15:10. Supraclavicular nodal coverage was highest in photon-only (mean = 96.2 ± 3.5%) followed closely by combined photon-electron (mean = 94.2 ± 2.5%) and lowest in electron-only plans (mean = 81.7 ± 14.8%, p supraclavicular nodal irradiation and results in adequate target coverage, acceptable dosimetric hotspot volume, and slightly reduced lung dose. Copyright © 2015 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  11. Focused-electron-beam-induced processing (FEBIP) for emerging applications in carbon nanoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Fedorov, Andrei G. [Georgia Institute of Technology, George W. Woodruff School of Mechanical Engineering, Atlanta, GA (United States); Georgia Institute of Technology, Parker H. Petit Institute for Bioengineering and Bioscience, Atlanta, GA (United States); Kim, Songkil; Henry, Mathias [Georgia Institute of Technology, George W. Woodruff School of Mechanical Engineering, Atlanta, GA (United States); Kulkarni, Dhaval; Tsukruk, Vladimir V. [Georgia Institute of Technology, School of Materials Science and Engineering, Atlanta, GA (United States)

    2014-07-27

    Focused-electron-beam-induced processing (FEBIP), a resist-free additive nanomanufacturing technique, is an actively researched method for ''direct-write'' processing of a wide range of structural and functional nanomaterials, with high degree of spatial and time-domain control. This article attempts to critically assess the FEBIP capabilities and unique value proposition in the context of processing of electronics materials, with a particular emphasis on emerging carbon (i.e., based on graphene and carbon nanotubes) devices and interconnect structures. One of the major hurdles in advancing the carbon-based electronic materials and device fabrication is a disjoint nature of various processing steps involved in making a functional device from the precursor graphene/CNT materials. Not only this multi-step sequence severely limits the throughput and increases the cost, but also dramatically reduces the processing reproducibility and negatively impacts the quality because of possible between-the-step contamination, especially for impurity-susceptible materials such as graphene. The FEBIP provides a unique opportunity to address many challenges of carbon nanoelectronics, especially when it is employed as part of an integrated processing environment based on multiple ''beams'' of energetic particles, including electrons, photons, and molecules. This avenue is promising from the applications' prospective, as such a multi-functional (electron/photon/molecule beam) enables one to define shapes (patterning), form structures (deposition/etching), and modify (cleaning/doping/annealing) properties with locally resolved control on nanoscale using the same tool without ever changing the processing environment. It thus will have a direct positive impact on enhancing functionality, improving quality and reducing fabrication costs for electronic devices, based on both conventional CMOS and emerging carbon (CNT/graphene) materials. (orig.)

  12. Extremely strong bipolar optical interactions in paired graphene nanoribbons.

    Science.gov (United States)

    Lu, Wanli; Chen, Huajin; Liu, Shiyang; Zi, Jian; Lin, Zhifang

    2016-03-28

    Graphene is an excellent multi-functional platform for electrons, photons, and phonons due to exceptional electronic, photonic, and thermal properties. When combining its extraordinary mechanical characteristics with optical properties, graphene-based nanostructures can serve as an appealing platform for optomechanical applications at the nanoscale. Here, we demonstrate, using full-wave simulations, the emergence of extremely strong bipolar optical forces, or, optical binding and anti-binding, between a pair of coupled graphene nanoribbons, due to the remarkable confinement and enhancement of optical fields arising from the large effective mode indices. In particular, the binding and anti-binding forces, which are about two orders of magnitude stronger than that in metamaterials and high-Q resonators, can be tailored by selective excitation of either the even or the odd optical modes, achievable by tuning the relative phase of the lightwaves propagating along the two ribbons. Based on the coupled mode theory, we derive analytical formulae for the bipolar optical forces, which agree well with the numerical results. The attractive optical binding force F(y)(b) and the repulsive anti-binding force F(y)(a) exhibit a remarkably different dependence on the gap distance g between the nanoribbons and the Fermi energy E(F), in the forms of F(y)(b) ∝ 1/√(g³E(F)) and F(y)(a) ∝ 1/E(F)(2). With E(F) dynamically tunable by bias voltage, the bipolar forces may provide a flexible handle for active control of the nanoscale optomechanical effects, and also, might be significant for optoelectronic and optothermal applications as well.

  13. Simultaneous photon and neutron interrogation using an electron accelerator in order to quantify actinides in encapsulated radioactive wastes; Double interrogation simultanee neutrons et photons utilisant un accelerateur d'electrons pour la caracterisation separee des actinides dans les dechets radioactifs enrobes

    Energy Technology Data Exchange (ETDEWEB)

    Jallu, F

    1999-09-24

    Measuring out alpha emitters, such as ({sup 234,235,236,238}U {sup 238,239,240,242,}2{sup 44P}u, {sup 237}Np {sup 241,243}Am...), in solid radioactive waste, allows us to quantify the alpha activity in a drum and then to classify it. The SIMPHONIE (SIMultaneous PHOton and Neutron Interrogation Experiment) method, developed in this Ph.D. work, combines both the Active Neutron Interrogation and the Induced Photofission Interrogation techniques simultaneously. Its purpose is to quantify in only one measurement, fissile ({sup 235}U, {sup 239,241}Pu...) and fertile ({sup 236,238}U, {sup 238,240}Pu...) elements separately. In the first chapter of this Ph.D. report, we present the principle of the Radioactive Waste Management in France. The second chapter deals with the physical properties of neutron fission and of photofission. These two nuclear reactions are the basis of the SIMPHONIE method. Moreover, one of our purposes was to develop the ELEPHANT (ELEctron PHoton And Neutron Transport) code in view to simulate the electron, photon and neutron transport, including the ({gamma}, n), ({gamma}, 2n) and ({gamma}, f) photonuclear reactions that are not taken into account in the MCNP4 (Monte Carlo N-Particle) code. The simulation codes developed and used in this work are detailed in the third chapter. Finally, the fourth chapter gives the experimental results of SIMPHONIE obtained by using the DGA/ETCA electron linear accelerators located at Arcueil, France. Fissile ({sup 235}U, {sup 239}Pu) and fertile ({sup 238}U) samples were studied. Furthermore, comparisons between experimental results and calculated data of photoneutron production in tungsten, copper, praseodymium and beryllium by using an electron LINear Accelerator (LINAC) are given. This allows us to evaluate the validity degree of the ELEPHANT code, and finally the feasibility of the SIMPHONIE method. (author)

  14. SU-E-T-659: Quantitative Evaluation of Patient Setup Accuracy of Stereotactic Radiotherapy with the Frameless 6D-ExacTrac System Using Statistical Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Keeling, V; Jin, H; Hossain, S; Algan, O; Ahmad, S; Ali, I [University of Oklahoma Health Science Center, Oklahoma City, OK (United States)

    2015-06-15

    Purpose: To evaluate patient setup accuracy and quantify individual and cumulative positioning uncertainties associated with different hardware and software components of the stereotactic radiotherapy (SRS/SRT) with the frameless-6D-ExacTrac system. Methods: A statistical model was used to evaluate positioning uncertainties of the different components of SRS/SRT treatment with the BrainLAB 6D-ExacTrac system using the positioning shifts of 35 patients having cranial lesions (49 total lesions treated in 1, 3, 5 fractions). All these patients were immobilized with rigid head-and-neck masks, simulated with BrainLAB-localizer and planned with iPlan treatment planning system. Infrared imaging (IR) was used initially to setup patients. Then, stereoscopic x-ray images (XC) were acquired and registered to corresponding digitally-reconstructed-radiographs using bony-anatomy matching to calculate 6D-translational and rotational shifts. When the shifts were within tolerance (0.7mm and 1°), treatment was initiated. Otherwise corrections were applied and additional x-rays were acquired (XV) to verify that patient position was within tolerance. Results: The uncertainties from the mask, localizer, IR-frame, x-ray imaging, MV and kV isocentricity were quantified individually. Mask uncertainty (Translational: Lateral, Longitudinal, Vertical; Rotational: Pitch, Roll, Yaw) was the largest and varied with patients in the range (−1.05−1.50mm, −5.06–3.57mm, −5.51−3.49mm; −1.40−2.40°, −1.24−1.74°, and −2.43−1.90°) obtained from mean of XC shifts for each patient. Setup uncertainty in IR positioning (0.88,2.12,1.40mm, and 0.64,0.83,0.96°) was extracted from standard-deviation of XC. Systematic uncertainties of the localizer (−0.03,−0.01,0.03mm, and −0.03,0.00,−0.01°) and frame (0.18,0.25,−1.27mm,−0.32,0.18, and 0.47°) were extracted from means of all XV setups and mean of all XC distributions, respectively. Uncertainties in isocentricity of the

  15. Hypofractionated stereotactic radiotherapy for brain metastases from lung cancer. Evaluation of indications and predictors of local control

    Energy Technology Data Exchange (ETDEWEB)

    Ishihara, Takeaki [Kobe University Graduate School of Medicine, Division of Radiation Oncology, Hyogo (Japan); Seirei Mikatahara General Hospital, Department of Radiation Oncology, Shizuoka (Japan); Yamada, Kazunari; Isogai, Kenta; Tonosaki, Yoshihiro [Seirei Mikatahara General Hospital, Department of Radiation Oncology, Shizuoka (Japan); Harada, Aya [Kobe Minimum Invasive Cancer Medical Center, Department of Radiation Oncology, Hyogo (Japan); Demizu, Yusuke [Hyogo Ion Beam Medical Center, Department of Radiology, Hyogo (Japan); Miyawaki, Daisuke; Yoshida, Kenji; Ejima, Yasuo; Sasaki, Ryohei [Kobe University Graduate School of Medicine, Division of Radiation Oncology, Hyogo (Japan)

    2016-06-15

    To evaluate the efficacy and toxicity of hypofractionated stereotactic radiotherapy (HSRT) for brain metastases (BMs) from lung cancer, and to explore prognostic factors associated with local control (LC) and indication. We evaluated patients who were treated with linac-based HSRT for BMs from lung cancer. Lesions treated with stereotactic radiosurgery (SRS) in the same patients during the same periods were analysed and compared with HSRT in terms of LC or toxicity. There were 53 patients with 214 lesions selected for this analysis (HSRT: 76 lesions, SRS: 138 lesions). For HSRT, the median prescribed dose was 35 Gy in 5 fractions. The 1-year LC rate was 83.6 % in HSRT; on multivariate analysis, a planning target volume (PTV) of <4 cm{sup 3}, biologically effective dose (BED{sub 10}) of ≥51 Gy, and adenocarcinoma were significantly associated with better LC. Moreover, in PTVs ≥ 4 cm{sup 3}, there was a significant difference in LC between BED{sub 10} < 51 Gy and ≥ 51 Gy (p = 0.024). On the other hand, in PTVs < 4 cm{sup 3}, both HSRT and SRS had good LC with no significant difference (p = 0.195). Radiation necrosis emerged in 5 of 76 lesions (6.6 %) treated with HSRT and 21 of 138 (15.2 %) lesions treated with SRS (p = 0.064). Linac-based HSRT was safe and effective for BMs from lung cancer, and hence might be particularly useful in or near an eloquent area. PTV, BED{sub 10}, and pathological type were significant prognostic factors. Furthermore, in BMs ≥ 4 cm{sup 3}, a dose of BED ≥ 51 Gy should be considered. (orig.) [German] Beurteilung von Wirksamkeit und Toxizitaet einer hypofraktionierten stereotaktischen Strahlentherapie (HSRT) zur Behandlung von Hirnmetastasen (HM) eines Lungenkarzinoms und Erforschung von mit der lokalen Kontrolle (LK) und der Indikation assoziierten Prognosefaktoren. Analysiert wurden Daten von Patienten (n = 53), die sich einer Linearbeschleuniger-basierten HSRT unterzogen (mit HSRT behandelte Laesionen n = 76; Median der

  16. SU-E-T-424: Feasibility of 3D Printed Radiological Equivalent Customizable Tissue Like Materials

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D; Ferreira, C; Ahmad, S [University of Oklahoma Health Science Center, Oklahoma City, OK (United States)

    2015-06-15

    Purpose: To investigate the feasibility of 3D printing CT# specific radiological equivalent tissue like materials. Methods: A desktop 3D printer was utilized to create a series of 3 cm x 3 cm x 2 cm PLA plastic blocks of varying fill densities. The fill pattern was selected to be hexagonal (Figure 1). A series of blocks was filled with paraffin and compared to a series filled with air. The blocks were evaluated with a “GE Lightspeed” 16 slice CT scanner and average CT# of the centers of the materials was determined. The attenuation properties of the subsequent blocks were also evaluated through their isocentric irradiation via “TrueBeam” accelerator under six beam energies. Blocks were placed upon plastic-water slabs of 4 cm in thickness assuring electronic equilibrium and data was collected via Sun Nuclear “Edge” diode detector. Relative changes in dose were compared with those predicted by Varian “Eclipse” TPS. Results: The CT# of 3D printed blocks was found to be a controllable variable. The fill material was able to narrow the range of variability in each sample. The attenuation of the block tracked with the density of the total fill structure. Assigned CT values in the TPS were seen to fall within an expected range predicted by the CT scans of the 3D printed blocks. Conclusion: We have demonstrated that it is possible to 3D print materials of varying tissue equivalencies, and that these materials have radiological properties that are customizable and predictable.

  17. A 4 MV flattening filter-free beam: commissioning and application to conformal therapy and volumetric modulated arc therapy

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, S W; Rosser, K E; Bedford, J L, E-mail: simon.stevens@nhs.net [Joint Department of Physics, Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT (United Kingdom)

    2011-07-07

    Recent studies have indicated that radiotherapy treatments undertaken on a flattening filter-free (FFF) linear accelerator have a number of advantages over treatments undertaken on a conventional linear accelerator. In addition, 4 MV photon beams may give improved isodose coverage for some treatment volumes at air/tissue interfaces, compared to when utilizing the clinical standard of 6 MV photons. In order to investigate these benefits, FFF beams were established on an Elekta Beam Modulator linear accelerator for 4 MV photons. Commissioning beam data were obtained for open and wedged fields. The measured data were then imported into a treatment planning system and a beam model was commissioned. The beam model was optimized to improve dose calculations at shallow, clinically relevant depths. Following verification, the beam model was utilized in a treatment planning study, including volumetric modulated arc therapy, for a selection of lung, breast/chest wall and larynx patients. Increased dose rates of around 800 MU min{sup -1} were recorded for open fields (relative to 320 MU min{sup -1} for filtered open fields) and reduced head scatter was inferred from output factor measurements. Good agreement between planned and delivered dose was observed in verification of treatment plans. The planning study indicated that with a FFF beam, equivalent (and in some cases improved) isodose profiles could be achieved for small lung and larynx treatment volumes relative to 4 MV filtered treatments. Furthermore, FFF treatments with wedges could be replicated using open fields together with an 'effective wedge' technique and isocentre shift. Clinical feasibility of a FFF beam was therefore demonstrated, with beam modelling, treatment planning and verification being successfully accomplished.

  18. Generalized EPID calibration for in vivo transit dosimetry.

    Science.gov (United States)

    Fidanzio, Andrea; Cilla, Savino; Greco, Francesca; Gargiulo, Laura; Azario, Luigi; Sabatino, Domenico; Piermattei, Angelo

    2011-01-01

    Many researchers are studying new in vivo dosimetry methods based on the use of Elelctronic portal imaging devices (EPIDs) that are simple and efficient in their daily use. However the need of time consuming implementation measurements with solid water phantoms for the in vivo dosimetry implementation can discourage someone in their use. In this paper a procedure has been proposed to calibrate aSi EPIDs for in vivo transit dosimetry. The dosimetric equivalence of three aSi Varian EPIDs has been investigated in terms of signal reproducibility and long term stability, signal linearity with MU and dose per pulse and signal dependence on the field dimensions. The signal reproducibility was within ± 0.5% (2SD), while the long term signal stability has been maintained well within ± 2%. The signal linearity with the monitor units (MU) was within ± 2% and within ± 0.5% for the EPIDs controlled by the IAS 2, and IAS 3 respectively. In particular it was verified that the correction factor for the signal linearity with the monitor units, k(lin), is independent of the beam quality, and the dose per pulse absorbed by the EPID. For 6, 10 and 15 MV photon beams, a generalized set of correlation functions F(TPR,w,L) and empirical factors f(TPR,d,L) as a function of the Tissue Phantom Ratio (TPR), the phantom thickness, w, the square field side, L, and the distance, d, between the phantom mid-plane and the isocentre were determined to reconstruct the isocenter dose. The tolerance levels of the present in vivo dosimetry method ranged between ± 5% and ± 6% depending on the tumor body location. In conclusion, the procedure proposed, that use generalized correlation functions, reduces the effort for the in vivo dosimetry method implementation for those photon beams with TPR within ± 0.3% as respect those here used.

  19. Delayed renal dysfunction after total body irradiation in pediatric malignancies.

    Science.gov (United States)

    Watanabe Nemoto, Miho; Isobe, Koichi; Togasaki, Gentaro; Kanazawa, Aki; Kurokawa, Marie; Saito, Makoto; Harada, Rintaro; Kobayashi, Hiroyuki; Ito, Hisao; Uno, Takashi

    2014-09-01

    The purpose of this study was to retrospectively evaluate the incidence of delayed renal dysfunction after total body irradiation (TBI) in long-term survivors of TBI/hematopoietic stem cell transplantation (HSCT). Between 1989 and 2006, 24 pediatric patients underwent TBI as part of the conditioning regimen for HSCT at Chiba University Hospital. Nine patients who survived for more than 5 years were enrolled in this study. No patient had any evidence of renal dysfunction prior to the transplant according to their baseline creatinine levels. The median age at the time of diagnosis was 6 years old (range: 1-17 years old). The follow-up period ranged from 79-170 months (median: 140 months). Renal dysfunction was assessed using the estimated glomerular filtration rate (eGFR). The TBI dose ranged from 8-12 Gy delivered in 3-6 fractions over 2-3 d. The patients were treated with linear accelerators in the supine position, and the radiation was delivered to isocentric right-left and left-right fields via the extended distance technique. The kidneys and the liver were not shielded except in one patient with a left adrenal neuroblastoma. No patient required hemodialysis. The eGFR of four patients (44.4%) progressively decreased. The remaining patients did not demonstrate any eGFR deterioration. Only one patient developed hypertension. By evaluating the changes in eGFR, renal dysfunction among long-term survivors of TBI/HSCT could be detected. Our results suggested that the TBI schedule of 12 Gy in 6 fractions over three consecutive days affects renal function.

  20. Feasibility of portal dosimetry for flattening filter-free radiotherapy.

    Science.gov (United States)

    Chuter, Robert W; Rixham, Philip A; Weston, Steve J; Cosgrove, Vivian P

    2016-01-08

    The feasibility of using portal dosimetry (PD) to verify 6 MV flattening filter-free (FFF) IMRT treatments was investigated. An Elekta Synergy linear accelerator with an Agility collimator capable of delivering FFF beams and a standard iViewGT amorphous silicon (aSi) EPID panel (RID 1640 AL5P) at a fixed SSD of 160 cm were used. Dose rates for FFF beams are up to four times higher than for conventional flattened beams, meaning images taken at maximum FFF dose rate can saturate the EPID. A dose rate of 800 MU/min was found not to saturate the EPID for open fields. This dose rate was subsequently used to characterize the EPID for FFF portal dosimetry. A range of open and phantom fields were measured with both an ion chamber and the EPID, to allow comparison between the two. The measured data were then used to create a model within The Nederlands Kanker Instituut's (NKI's) portal dosimetry software. The model was verified using simple square fields with a range of field sizes and phantom thicknesses. These were compared to calculations performed with the Monaco treatment planning system (TPS) and isocentric ion chamber measurements. It was found that the results for the FFF verification were similar to those for flattened beams with testing on square fields, indicating a difference in dose between the TPS and portal dosimetry of approximately 1%. Two FFF IMRT plans (prostate and lung SABR) were delivered to a homogeneous phantom and showed an overall dose difference at isocenter of ~0.5% and good agreement between the TPS and PD dose distributions. The feasibility of using the NKI software without any modifications for high-dose-rate FFF beams and using a standard EPID detector has been investigated and some initial limitations highlighted.

  1. Three-dimensional dose distribution of tangential breast treatment; A national dosimetry intercomparison

    Energy Technology Data Exchange (ETDEWEB)

    Bree, N.A.M. van; Battum, L.J. van (Nederlands Kanker Inst. ' Antoni van Leeuwenhoekhuis' , Amsterdam (Netherlands) Dr. Daniel Den Hoed Cancer Centre, Rotterdam (Netherlands). Department of Clinical Physics); Huizenga, H.; Mijnheer, B.J. (Nederlands Kanker Inst. ' Antoni van Leeuwenhoekhuis' , Amsterdam (Netherlands))

    1991-12-01

    From Aug.'90-Feb.'91, dosimetry intercomparison of breast treatment was performed at all 21 radiotherapy centres in The Netherlands. The absorbed dose was measured in three planes in a breast phantom during tangential breast irradiation, according to a prescribed technique. The beam energy could be chosen by the radiotherapy centre as normally applied for this type of 'patient', and varied between {sup 60}Co and 8MV X-rays. The dose measured by the visiting team in 22 points inside the phantom was compared with the dose calculated by the institution using their local treatment planning system. In the institutions mean ratio (mean value of ratios of the absolute calculated dose and measured absolute dose in the 22 points) varied between 0.92-1.08 with an over-all mean ratio of 1.04. There was no significant difference in this ratio between the 3 planes in a particular institution. In the isocentre mean ratio of calculated and measured dose was 1.021 with a SD of 0.028 i.e. the algorithms in the 6 different commercial treatment planning systems calculate the dose generally somewhat too high. In order to explain results, a measurement of the output under reference conditions was performed at each treatment unit. Mean ratio of the dose stated by the institution and the dose measured by the visiting team was 1.011 with a 0.015-SD with a maximum deviation of 0.040. This small deviation explains therefore only part of variation in the ratio of calculated and measured dose for tangential breast irradiation. In several centres large deviations between actual beam data and beam data implemented in the planning system were found, which was the main reason for observed discrepancies. (author). 15 refs.; 5 figs.; 2 tabs.

  2. Quality assurance of the EORTC trial 22881/10882 : 'assessment of the role of the booster dose in breast conserving therapy'; The Dummy Run

    Energy Technology Data Exchange (ETDEWEB)

    Tienhoven, G. van; Bree, N.A.M. van; Mijnheer, B.J.; Bartelink, H. (Nederlands Kanker Inst. ' Antoni van Leeuwenhoekhuis' , Amsterdam (Netherlands) the EORTC Radiotherapy Group)

    1991-12-01

    The EORTC trial 22881/10882 is a randomised trial with the aim to assess the role of the boost dose in breast conserving therapy in stage I and II breast cancer.In order to detect potential protocol deviations concerning irradiation technique and in dose specification procedure of participating institutions before actual patient accrual, a Dummy Run was performed. Three transverse sections of a patient were sent to 16 institutions with a request to make a 3-plane treatment plan according to protocol prescriptions. A treatment chart and beam data were also requested for recalculation of the dose. Additional information was asked in a questionnaire. On evaluation, the techniques differed considerably with respect to photon beam energy, varying between {sup 60}Co gamma-rays and 8MV X-rays, and use of wedge filters. Two institutions did not apply wedges, whereas wedge angles in the other institutions varied between 6deg and 45 deg. Twelve institutions used collimator rotation and/or a table wedge to diminish the amount of irradiated lung volume. The dose was specified in a point according to the protocol prescription in 11 institutions and to the 90, 95 or 100% isodose curve in four. Twelve institutions applied lung density corrections during treatment planning, while nine reported problems with their planning system in off-axis dose distribution calculation and/or the stimulation of collimator rotation. Recalculation of dose at the isocentre showed agreement within 2% compared with stated dose. Dose reported in the tumor excision area varied between 93 and 100%. It can be concluded that good accordance and high quality breast irradiation can be achieved by all institutions participating in the trial, provided a few recommendations are followed. The results of this analysis show the necessity and usefulness of a quality assurance programme at the initial phase of a clinical trial. (author). 27 refs.; 3 figs.; 4 tabs.

  3. The role of high-energy computed radiography (CR) in radiotherapy

    Institute of Scientific and Technical Information of China (English)

    LI Zhaobin; SUN Yi; LU Yaohong; FU Shen

    2009-01-01

    Computed radiography (CR) imaging has high irradiation tolerance and it is easy to archive CR images along with other image information by Digital Imaging and Communications in Medicine (DICOM) format,and to process them.CR can be used in radiation Quality Control (QC) task and verification of treatment setting-up.In this paper,the role of high-energy CR in radiation oncology is studied.The patients were imaged by CR system and EPID before radiotherapy.All verification images were acquired with 1-2 MU (Monitor Unit) using 6 MV X-rays.QC for a tinac was done with film and high-energy CR to collect the data on daily,weekly and monthly basis.The QC included Multileaf Collimators (MLC) calibration and mechanical iso-centre check.CR was also adapted to verify patient position,the film was used to compare with digitally reconstructed radiographs (DRR) and portal image from EPID.Treatment setting-up was verified based on the result of comparison.High quality verification images cou ld beacquired by the CR system.Comparing to EPID,the results showed that the system was suitable for practical use to acquire daffy verification images,and it was useful to fulfill part of quality assurance (QA) in radiation oncology.The quality of image acquired by the high-energy CR system is comparable or even better than DRRs and portal images.The final treatment set-up for the patients could be verified more accurately with the CR system.

  4. Visual Outcome in Meningiomas Around Anterior Visual Pathways Treated With Linear Accelerator Fractionated Stereotactic Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Stiebel-Kalish, Hadas, E-mail: kalishhadas@gmail.com [Neuro-Ophthalmology Unit, Rabin Medical Center, Petah Tikva (Israel); Sackler School of Medicine, Tel Aviv University, Tel Aviv (Israel); Reich, Ehud [Sackler School of Medicine, Tel Aviv University, Tel Aviv (Israel); Department of Ophthalmology, Rabin Medical Center, Petah Tikva (Israel); Gal, Lior [Sackler School of Medicine, Tel Aviv University, Tel Aviv (Israel); Rappaport, Zvi Harry [Sackler School of Medicine, Tel Aviv University, Tel Aviv (Israel); Department of Neurosurgery, Rabin Medical Center, Petah Tikva (Israel); Nissim, Ouzi [Sackler School of Medicine, Tel Aviv University, Tel Aviv (Israel); Stereotactic Radiosurgery Unit, Sheba Medical Center, Ramat Gan (Israel); Department of Neurosurgery, Sheba Medical Center, Ramat Gan (Israel); Pfeffer, Raphael [Sackler School of Medicine, Tel Aviv University, Tel Aviv (Israel); Stereotactic Radiosurgery Unit, Sheba Medical Center, Ramat Gan (Israel); Spiegelmann, Roberto [Sackler School of Medicine, Tel Aviv University, Tel Aviv (Israel); Stereotactic Radiosurgery Unit, Sheba Medical Center, Ramat Gan (Israel); Department of Neurosurgery, Sheba Medical Center, Ramat Gan (Israel)

    2012-02-01

    Purpose: Meningiomas threatening the anterior visual pathways (AVPs) and not amenable for surgery are currently treated with multisession stereotactic radiotherapy. Stereotactic radiotherapy is available with a number of devices. The most ubiquitous include the gamma knife, CyberKnife, tomotherapy, and isocentric linear accelerator systems. The purpose of our study was to describe a case series of AVP meningiomas treated with linear accelerator fractionated stereotactic radiotherapy (FSRT) using the multiple, noncoplanar, dynamic conformal rotation paradigm and to compare the success and complication rates with those reported for other techniques. Patients and Methods: We included all patients with AVP meningiomas followed up at our neuro-ophthalmology unit for a minimum of 12 months after FSRT. We compared the details of the neuro-ophthalmologic examinations and tumor size before and after FSRT and at the end of follow-up. Results: Of 87 patients with AVP meningiomas, 17 had been referred for FSRT. Of the 17 patients, 16 completed >12 months of follow-up (mean 39). Of the 16 patients, 11 had undergone surgery before FSRT and 5 had undergone FSRT as first-line management. Tumor control was achieved in 14 of the 16 patients, with three meningiomas shrinking in size after RT. Two meningiomas progressed, one in an area that was outside the radiation field. The visual function had improved in 6 or stabilized in 8 of the 16 patients (88%) and worsened in 2 (12%). Conclusions: Linear accelerator fractionated RT using the multiple noncoplanar dynamic rotation conformal paradigm can be offered to patients with meningiomas that threaten the anterior visual pathways as an adjunct to surgery or as first-line treatment, with results comparable to those reported for other stereotactic RT techniques.

  5. X-ray tube current modulation and patient doses in chest CT.

    Science.gov (United States)

    He, Wenjun; Huda, Walter; Magill, Dennise; Tavrides, Emily; Yao, Hai

    2011-01-01

    The aim of the study was to investigate how patient effective doses vary as a function of X-ray tube projection angle, as well as the patient long axis, and quantify how X-ray tube current modulation affects patient doses in chest CT examinations. Chest examinations were simulated for a gantry CT scanner geometry with projections acquired for a beam width of 4 cm. PCXMC 2.0.1 was used to calculate patient effective doses at 15° intervals around the patient's isocentre, and at nine locations along the patient long axis. Idealised tube current modulation schemes were modelled as a function of the X-ray tube angle and the patient long axis. Tube current modulations were characterised by the modulation amplitude R, which was allowed to vary between 1.5 and 5. Effective dose maxima occur for anteroposterior projections at the location of the (radiosensitive) breasts. The maximum to minimum ratio of effective doses as a function of the patient long axis was 4.9, and as a function of the X-ray tube angle was 2.1. Doubling the value of R reduces effective doses from longitudinal modulation alone by ∼4% and from angular modulation alone by ∼2%. In chest CT, tube current modulation schemes currently have longitudinal R values of ∼2.2, and angular R values that range between 1.5 and 3.4. Current X-ray tube current modulation schemes are expected to reduce patient effective doses in chest CT examinations by ∼10%, with longitudinal modulation accounting for two-thirds and angular modulation for the remaining one-third.

  6. Towards a Noninvasive Intracranial Tumor Irradiation Using 3D Optical Imaging and Multimodal Data Registration

    Science.gov (United States)

    Posada, R.; Daul, Ch.; Wolf, D.; Aletti, P.

    2007-01-01

    Conformal radiotherapy (CRT) results in high-precision tumor volume irradiation. In fractioned radiotherapy (FRT), lesions are irradiated in several sessions so that healthy neighbouring tissues are better preserved than when treatment is carried out in one fraction. In the case of intracranial tumors, classical methods of patient positioning in the irradiation machine coordinate system are invasive and only allow for CRT in one irradiation session. This contribution presents a noninvasive positioning method representing a first step towards the combination of CRT and FRT. The 3D data used for the positioning is point clouds spread over the patient's head (CT-data usually acquired during treatment) and points distributed over the patient's face which are acquired with a structured light sensor fixed in the therapy room. The geometrical transformation linking the coordinate systems of the diagnosis device (CT-modality) and the 3D sensor of the therapy room (visible light modality) is obtained by registering the surfaces represented by the two 3D point sets. The geometrical relationship between the coordinate systems of the 3D sensor and the irradiation machine is given by a calibration of the sensor position in the therapy room. The global transformation, computed with the two previous transformations, is sufficient to predict the tumor position in the irradiation machine coordinate system with only the corresponding position in the CT-coordinate system. Results obtained for a phantom show that the mean positioning error of tumors on the treatment machine isocentre is 0.4 mm. Tests performed with human data proved that the registration algorithm is accurate (0.1 mm mean distance between homologous points) and robust even for facial expression changes. PMID:18364992

  7. Effect of titanium dental implants on proton therapy delivered for head tumors: experimental validation using an anthropomorphic head phantom

    Science.gov (United States)

    Oancea, C.; Shipulin, K.; Mytsin, G.; Molokanov, A.; Niculae, D.; Ambrožová, I.; Davídková, M.

    2017-03-01

    A dosimetric experiment was performed at the Medico-Technical Complex in the Joint Institute for Nuclear Research, Dubna, to investigate the effects of metallic dental implants in the treatment of head and neck tumours with proton therapy. The goal of the study was to evaluate the 2D dose distributions of different clinical treatment plans measured in an anthropomorphic phantom, and compare them to predictions from a treatment planning system. The anthropomorphic phantom was sliced into horizontal segments. Two grade 4 Titanium implants were inserted between 2 slices, corresponding to a maxillary area. GafChromic EBT2 films were placed between the segments containing the implants to measure the 2D delivered dose. Two different targets were designed: the first target includes the dental implants in the isocentre, and in the second target, the proton beam is delivered through the implants, which are located at the entrance region of the Bragg curve. The experimental results were compared to the treatment plans made using our custom 3D Treatment Planning System, named RayTreat. To quantitatively determine differences in the isodose distributions (measured and calculated), the gamma index (3 mm, 3%) was calculated for each target for the matrix value in the region of high isodose (> 90%): for the experimental setup, which includes the implants in the SOBP region, the result obtained was 84.3%. When the implants were localised in the entrance region of the Bragg curve, the result obtained was 86.4%. In conclusion, the uncertainties introduced by the clinically planned dose distribution are beyond reasonable limits. The linear energy transfer spectra in close proximity to the implants were investigated using solid state nuclear track detectors (TED). Scattered particles outside the target were detected.

  8. Microionization chamber for reference dosimetry in IMRT verification: clinical implications on OAR dosimetric errors

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Doblado, Francisco [Hospital Universitario Virgen Macarena, RadiofIsica, Sevilla (Spain); Capote, Roberto [International Atomic Energy Agency, Nuclear Data Section, Vienna (Austria); Leal, Antonio [Hospital Universitario Virgen Macarena, RadiofIsica, Sevilla (Spain); Rosello, Joan V [RadiofIsica, ERESA, Hospital General Universitario, Valencia (Spain); Lagares, Juan I [Hospital Universitario Virgen Macarena, RadiofIsica, Sevilla (Spain); Arrans, Rafael [Hospital Universitario Virgen Macarena, RadiofIsica, Sevilla (Spain); Hartmann, Guenther H [Deutsches Krebsforschungszentrum, Abt. Medizinische Physik, Heidelberg (Germany)

    2005-03-07

    Intensity modulated radiotherapy (IMRT) has become a treatment of choice in many oncological institutions. Small fields or beamlets with sizes of 1 to 5 cm{sup 2} are now routinely used in IMRT delivery. Therefore small ionization chambers (IC) with sensitive volumes {<=}0.1 cm{sup 3}are generally used for dose verification of an IMRT treatment. The measurement conditions during verification may be quite different from reference conditions normally encountered in clinical beam calibration, so dosimetry of these narrow photon beams pertains to the so-called non-reference conditions for beam calibration. This work aims at estimating the error made when measuring the organ at risk's (OAR) absolute dose by a micro ion chamber ({mu}IC) in a typical IMRT treatment. The dose error comes from the assumption that the dosimetric parameters determining the absolute dose are the same as for the reference conditions. We have selected two clinical cases, treated by IMRT, for our dose error evaluations. Detailed geometrical simulation of the {mu}IC and the dose verification set-up was performed. The Monte Carlo (MC) simulation allows us to calculate the dose measured by the chamber as a dose averaged over the air cavity within the ion-chamber active volume (D{sub air}). The absorbed dose to water (D{sub water}) is derived as the dose deposited inside the same volume, in the same geometrical position, filled and surrounded by water in the absence of the ion chamber. Therefore, the D{sub water}/D{sub air} dose ratio is the MC estimator of the total correction factor needed to convert the absorbed dose in air into the absorbed dose in water. The dose ratio was calculated for the {mu}IC located at the isocentre within the OARs for both clinical cases. The clinical impact of the calculated dose error was found to be negligible for the studied IMRT treatments.

  9. SU-E-T-464: Implementation and Validation of 4D Acuros XB Dose Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, S; Yuen, C [BC Cancer Agency, Vancouver, BC (Canada); Huang, V [BC Cancer Agency, Surrey, BC (United Kingdom); Milette, M; Teke, T [BC Cancer Agency-Southern Interior, Kelowna, BC (Canada)

    2015-06-15

    Purpose: In this abstract we implement and validate a 4D VMAT Acuros XB dose calculation using Gafchromic film. Special attention is paid to the physical material assignment in the CT dataset and to reported dose to water and dose to medium. Methods: A QUASAR phantom with a 3 cm sinusoidal tumor motion and 5 second period was scanned using 4D computed tomography. A CT was also obtained of the static QUASAR phantom with the tumor at the central position. A VMAT plan was created on the average CT dataset and was delivered on a Varian TrueBeam linear accelerator. The trajectory log file from this treatment was acquired and used to create 10 VMAT subplans (one for each portion of the breathing cycle). Motion for each subplan was simulated by moving the beam isocentre in the superior/inferior direction in the Treatment Planning System on the static CT scan. The 10 plans were calculated (both dose to medium and dose to water) and summed for 1) the original HU values from the static CT scan and 2) the correct physical material assignment in the CT dataset. To acquire a breathing phase synchronized film measurements the trajectory log was used to create a VMAT delivery plan which includes dynamic couch motion using the Developer Mode. Three different treatment start phases were investigated (mid inhalation, full inhalation and full exhalation). Results: For each scenario the coronal dose distributions were measured using Gafchromic film and compared to the corresponding calculation with Film QA Pro Software using a Gamma test with a 3%/3mm distance to agreement criteria. Good agreement was found between calculation and measurement. No statistically significant difference in agreement was found between calculations to original HU values vs calculations to over-written (material-assigned) HU values. Conclusion: The investigated 4D dose calculation method agrees well with measurement.

  10. Dosimetric accuracy of a staged radiosurgery treatment

    Science.gov (United States)

    Cernica, George; de Boer, Steven F.; Diaz, Aidnag; Fenstermaker, Robert A.; Podgorsak, Matthew B.

    2005-05-01

    For large cerebral arteriovenous malformations (AVMs), the efficacy of radiosurgery is limited since the large doses necessary to produce obliteration may increase the risk of radiation necrosis to unacceptable levels. An alternative is to stage the radiosurgery procedure over multiple stages (usually two), effectively irradiating a smaller volume of the AVM nidus with a therapeutic dose during each session. The difference between coordinate systems defined by sequential stereotactic frame placements can be represented by a translation and a rotation. A unique transformation can be determined based on the coordinates of several fiducial markers fixed to the skull and imaged in each stereotactic coordinate system. Using this transformation matrix, isocentre coordinates from the first stage can be displayed in the coordinate system of subsequent stages allowing computation of a combined dose distribution covering the entire AVM. The accuracy of this approach was tested on an anthropomorphic head phantom and was verified dosimetrically. Subtle defects in the phantom were used as control points, and 2 mm diameter steel balls attached to the surface were used as fiducial markers and reference points. CT images (2 mm thick) were acquired. Using a transformation matrix developed with two frame placements, the predicted locations of control and reference points had an average error of 0.6 mm near the fiducial markers and 1.0 mm near the control points. Dose distributions in a staged treatment approach were accurately calculated using the transformation matrix. This approach is simple, fast and accurate. Errors were small and clinically acceptable for Gamma Knife radiosurgery. Accuracy can be improved by reducing the CT slice thickness.

  11. Dosimetric accuracy of a staged radiosurgery treatment

    Energy Technology Data Exchange (ETDEWEB)

    Cernica, George [Department of Physics, State University of New York at Buffalo, Buffalo, NY 14263 (United States); Boer, Steven F de [Department of Radiation Oncology, Roswell Park Cancer Institute and the State University of New York at Buffalo, Buffalo, NY 14263 (United States); Diaz, Aidnag [Department of Radiation Oncology, Roswell Park Cancer Institute and the State University of New York at Buffalo, Buffalo, NY 14263 (United States); Fenstermaker, Robert A [Department of Neurosurgery, Roswell Park Cancer Institute and the State University of New York at Buffalo, Buffalo, NY 14263 (United States); Podgorsak, Matthew B [Department of Radiation Oncology, Roswell Park Cancer Institute and the State University of New York at Buffalo, Buffalo, NY 14263 (United States)

    2005-05-07

    For large cerebral arteriovenous malformations (AVMs), the efficacy of radiosurgery is limited since the large doses necessary to produce obliteration may increase the risk of radiation necrosis to unacceptable levels. An alternative is to stage the radiosurgery procedure over multiple stages (usually two), effectively irradiating a smaller volume of the AVM nidus with a therapeutic dose during each session. The difference between coordinate systems defined by sequential stereotactic frame placements can be represented by a translation and a rotation. A unique transformation can be determined based on the coordinates of several fiducial markers fixed to the skull and imaged in each stereotactic coordinate system. Using this transformation matrix, isocentre coordinates from the first stage can be displayed in the coordinate system of subsequent stages allowing computation of a combined dose distribution covering the entire AVM. The accuracy of this approach was tested on an anthropomorphic head phantom and was verified dosimetrically. Subtle defects in the phantom were used as control points, and 2 mm diameter steel balls attached to the surface were used as fiducial markers and reference points. CT images (2 mm thick) were acquired. Using a transformation matrix developed with two frame placements, the predicted locations of control and reference points had an average error of 0.6 mm near the fiducial markers and 1.0 mm near the control points. Dose distributions in a staged treatment approach were accurately calculated using the transformation matrix. This approach is simple, fast and accurate. Errors were small and clinically acceptable for Gamma Knife radiosurgery. Accuracy can be improved by reducing the CT slice thickness.

  12. Dosimetry and field matching for radiotherapy to the breast and superclavicular fossa

    Science.gov (United States)

    Winfield, Elizabeth

    Radiotherapy for early breast cancer aims to achieve local disease control and decrease loco-regional recurrence rates. Treatment may be directed to breast or chest wall alone or, include regional lymph nodes. When using tangential fields to treat the breast a separate anterior field directed to the axilla and supraclavicular fossa (SCF) is needed to treat nodal areas. The complex geometry of this region necessitates matching of adjacent radiation fields in three dimensions. The potential exists for zones of overdosage or underdosage along the match line. Cosmetic results may be compromised if treatment fields are not accurately aligned. Techniques for field matching vary between centres in the UK. A study of dosimetry across the match line region using different techniques, as reported in the multi-centre START Trial Quality Assurance (QA) programme, was undertaken. A custom-made anthropomorphic phantom was designed to assess dose distribution in three dimensions using film dosimetry. Methods with varying degrees of complexity were employed to match tangential and SCF beams. Various techniques combined half beam blocking and machine rotations to achieve geometric alignment. Matching of asymmetric beams allowed a single isocentre technique to be used. Where field matching was not undertaken a gap between tangential and SCF fields was employed. Results demonstrated differences between techniques in addition to variations within the same technique between different centres. Geometric alignment techniques produced more homogenous dose distributions in the match region than gap techniques or those techniques not correcting for field divergence. For this multi-centre assessment of match plane techniques film dosimetry used in conjunction with a breast shaped phantom provided relative dose information. This study has highlighted the difficulties of matching treatment fields to achieve homogenous dose distribution through the region of the match plane and the degree of

  13. Comparative study of four advanced 3d-conformal radiation therapy treatment planning techniques for head and neck cancer.

    Science.gov (United States)

    Herrassi, Mohamed Yassine; Bentayeb, Farida; Malisan, Maria Rosa

    2013-04-01

    For the head-and-neck cancer bilateral irradiation, intensity-modulated radiation therapy (IMRT) is the most reported technique as it enables both target dose coverage and organ-at-risk (OAR) sparing. However, during the last 20 years, three-dimensional conformal radiotherapy (3DCRT) techniques have been introduced, which are tailored to improve the classic shrinking field technique, as regards both planning target volume (PTV) dose conformality and sparing of OAR's, such as parotid glands and spinal cord. In this study, we tested experimentally in a sample of 13 patients, four of these advanced 3DCRT techniques, all using photon beams only and a unique isocentre, namely Bellinzona, Forward-Planned Multisegments (FPMS), ConPas, and field-in-field (FIF) techniques. Statistical analysis of the main dosimetric parameters of PTV and OAR's DVH's as well as of homogeneity and conformity indexes was carried out in order to compare the performance of each technique. The results show that the PTV dose coverage is adequate for all the techniques, with the FPMS techniques providing the highest value for D95%; on the other hand, the best sparing of parotid glands is achieved using the FIF and ConPas techniques, with a mean dose of 26 Gy to parotid glands for a PTV prescription dose of 54 Gy. After taking into account both PTV coverage and parotid sparing, the best global performance was achieved by the FIF technique with results comparable to that of IMRT plans. This technique can be proposed as a valid alternative when IMRT equipment is not available or patient is not suitable for IMRT treatment.

  14. Radical stereotactic radiosurgery with real-time tumor motion tracking in the treatment of small peripheral lung tumors

    Directory of Open Access Journals (Sweden)

    Chang Thomas

    2007-10-01

    Full Text Available Abstract Background Recent developments in radiotherapeutic technology have resulted in a new approach to treating patients with localized lung cancer. We report preliminary clinical outcomes using stereotactic radiosurgery with real-time tumor motion tracking to treat small peripheral lung tumors. Methods Eligible patients were treated over a 24-month period and followed for a minimum of 6 months. Fiducials (3–5 were placed in or near tumors under CT-guidance. Non-isocentric treatment plans with 5-mm margins were generated. Patients received 45–60 Gy in 3 equal fractions delivered in less than 2 weeks. CT imaging and routine pulmonary function tests were completed at 3, 6, 12, 18, 24 and 30 months. Results Twenty-four consecutive patients were treated, 15 with stage I lung cancer and 9 with single lung metastases. Pneumothorax was a complication of fiducial placement in 7 patients, requiring tube thoracostomy in 4. All patients completed radiation treatment with minimal discomfort, few acute side effects and no procedure-related mortalities. Following treatment transient chest wall discomfort, typically lasting several weeks, developed in 7 of 11 patients with lesions within 5 mm of the pleura. Grade III pneumonitis was seen in 2 patients, one with prior conventional thoracic irradiation and the other treated with concurrent Gefitinib. A small statistically significant decline in the mean % predicted DLCO was observed at 6 and 12 months. All tumors responded to treatment at 3 months and local failure was seen in only 2 single metastases. There have been no regional lymph node recurrences. At a median follow-up of 12 months, the crude survival rate is 83%, with 3 deaths due to co-morbidities and 1 secondary to metastatic disease. Conclusion Radical stereotactic radiosurgery with real-time tumor motion tracking is a promising well-tolerated treatment option for small peripheral lung tumors.

  15. Procedure to measure the neutrons spectrum around a lineal accelerator for radiotherapy; Procedimiento para medir el espectro de los neutrones en torno a un acelerador lineal para radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R.; Hernandez D, V. M.; Letechipia de L, C. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas (Mexico); Benites R, J. L. [Servicios de Salud de Nayarit, Centro Estatal de Cancerologia, Calzada de la Cruz 116 Sur, 63000 Tepic, Nayarit (Mexico); Salas L, M. A., E-mail: fermineutron@yahoo.com [Universidad Autonoma de Zacatecas, Unidad Academica de Agronomia, Apdo. Postal 336, 98000 Zacatecas (Mexico)

    2013-10-15

    An experimental procedure was developed, by means of Bonner spheres, to measure the neutrons spectrum around Linacs of medical use that only requires of a single shot of the accelerator; to this procedure we denominate Planetary or Isocentric method. One of the problems associated to the neutrons spectrum measurement in a radiotherapy room with lineal accelerator is because inside the room a mixed, intense and pulsed radiation field takes place affecting the detection systems based on active detector; this situation is solved using a passive detector. In the case of the Bonner spheres spectrometer the active detector has been substituted by activation detectors, trace detectors or thermoluminescent dosimeters. This spectrometer uses several spheres that are situated one at a time in the measurement point, this way to have the complete measurements group the accelerator should be operated, under the same conditions, so many times like spheres have the spectrometer, this activity can consume a long time and in occasions due to the work load of Linac to complicate the measurement process too. The procedure developed in this work consisted on to situate all the spectrometer spheres at the same time and to make the reading by means of a single shot, to be able to apply this procedure, is necessary that before the measurements two characteristics are evaluated: the cross-talking of the spheres and the symmetry conditions of the neutron field. This method has been applied to determine the photo-neutrons spectrum produced by a lineal accelerator of medical use Varian ix of 15 MV to 100 cm of the isocenter located to 5 cm of depth of a solid water mannequin of 30 x 30 x 15 cm. The spectrum was used to determine the total flow and the environmental dose equivalent. (Author)

  16. Dosimetric and radiobiological consequences of computed tomography-guided adaptive strategies for intensity modulated radiation therapy of the prostate.

    Science.gov (United States)

    Battista, Jerry J; Johnson, Carol; Turnbull, David; Kempe, Jeff; Bzdusek, Karl; Van Dyk, Jacob; Bauman, Glenn

    2013-12-01

    To examine a range of scenarios for image-guided adaptive radiation therapy of prostate cancer, including different schedules for megavoltage CT imaging, patient repositioning, and dose replanning. We simulated multifraction dose distributions with deformable registration using 35 sets of megavoltage CT scans of 13 patients. We computed cumulative dose-volume histograms, from which tumor control probabilities and normal tissue complication probabilities (NTCPs) for rectum were calculated. Five-field intensity modulated radiation therapy (IMRT) with 18-MV x-rays was planned to achieve an isocentric dose of 76 Gy to the clinical target volume (CTV). The differences between D95, tumor control probability, V70Gy, and NTCP for rectum, for accumulated versus planned dose distributions, were compared for different target volume sizes, margins, and adaptive strategies. The CTV D95 for IMRT treatment plans, averaged over 13 patients, was 75.2 Gy. Using the largest CTV margins (10/7 mm), the D95 values accumulated over 35 fractions were within 2% of the planned value, regardless of the adaptive strategy used. For tighter margins (5 mm), the average D95 values dropped to approximately 73.0 Gy even with frequent repositioning, and daily replanning was necessary to correct this deficit. When personalized margins were applied to an adaptive CTV derived from the first 6 treatment fractions using the STAPLE (Simultaneous Truth and Performance Level Estimation) algorithm, target coverage could be maintained using a single replan 1 week into therapy. For all approaches, normal tissue parameters (rectum V(70Gy) and NTCP) remained within acceptable limits. The frequency of adaptive interventions depends on the size of the CTV combined with target margins used during IMRT optimization. The application of adaptive target margins (adaptive CTV determined 1 week into therapy minimizes the need for subsequent dose replanning. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Determinants of image quality of rotational angiography for on-line assessment of frame geometry after transcatheter aortic valve implantation.

    Science.gov (United States)

    Rodríguez-Olivares, Ramón; El Faquir, Nahid; Rahhab, Zouhair; Maugenest, Anne-Marie; Van Mieghem, Nicolas M; Schultz, Carl; Lauritsch, Guenter; de Jaegere, Peter P T

    2016-07-01

    To study the determinants of image quality of rotational angiography using dedicated research prototype software for motion compensation without rapid ventricular pacing after the implantation of four commercially available catheter-based valves. Prospective observational study including 179 consecutive patients who underwent transcatheter aortic valve implantation (TAVI) with either the Medtronic CoreValve (MCS), Edward-SAPIEN Valve (ESV), Boston Sadra Lotus (BSL) or Saint-Jude Portico Valve (SJP) in whom rotational angiography (R-angio) with motion compensation 3D image reconstruction was performed. Image quality was evaluated from grade 1 (excellent image quality) to grade 5 (strongly degraded). Distinction was made between good (grades 1, 2) and poor image quality (grades 3-5). Clinical (gender, body mass index, Agatston score, heart rate and rhythm, artifacts), procedural (valve type) and technical variables (isocentricity) were related with the image quality assessment. Image quality was good in 128 (72 %) and poor in 51 (28 %) patients. By univariable analysis only valve type (BSL) and the presence of an artefact negatively affected image quality. By multivariate analysis (in which BMI was forced into the model) BSL valve (Odds 3.5, 95 % CI [1.3-9.6], p = 0.02), presence of an artifact (Odds 2.5, 95 % CI [1.2-5.4], p = 0.02) and BMI (Odds 1.1, 95 % CI [1.0-1.2], p = 0.04) were independent predictors of poor image quality. Rotational angiography with motion compensation 3D image reconstruction using a dedicated research prototype software offers good image quality for the evaluation of frame geometry after TAVI in the majority of patients. Valve type, presence of artifacts and higher BMI negatively affect image quality.

  18. SU-E-J-176: Characterization of Inter-Fraction Breast Variability and the Implications On Delivered Dose

    Energy Technology Data Exchange (ETDEWEB)

    Sudhoff, M; Lamba, M; Kumar, N; Ward, A; Elson, H [University of Cincinnati, Cincinnati, OH (United States)

    2015-06-15

    Purpose: To systematically characterize inter-fraction breast variability and determine implications on delivered dose. Methods: Weekly port films were used to characterize breast setup variability. Five evenly spaced representative positions across the contour of each breast were chosen on the electronic port film in reference to graticule, and window and level was set such that the skin surface of the breast was visible. Measurements from the skin surface to treatment field edge were taken on each port film at each position and compared to the planning DRR, quantifying the variability. The systematic measurement technique was repeated for all port films for 20 recently treated breast cancer patients. Measured setup variability for each patient was modeled as a normal distribution. The distribution was randomly sampled from the model and applied as isocentric shifts in the treatment planning computer, representing setup variability for each fraction. Dose was calculated for each shifted fraction and summed to obtain DVHs and BEDs that modeled the dose with daily setup variability. Patients were categorized in to relevant groupings that were chosen to investigate the rigorousness of immobilization types, treatment techniques, and inherent anatomical difficulties. Mean position differences and dosimetric differences were evaluated between planned and delivered doses. Results: The setup variability was found to follow a normal distribution with mean position differences between the DRR and port film between − 8.6–3.5 mm with sigma range of 5.3–9.8 mm. Setup position was not found to be significantly different than zero. The mean seroma or whole breast PTV dosimetric difference, calculated as BED, ranged from a −0.23 to +1.13Gy. Conclusion: A systematic technique to quantify and model setup variability was used to calculate the dose in 20 breast cancer patients including variable setup. No statistically significant PTV or OAR BED differences were found between