WorldWideScience

Sample records for clinical linear accelerators

  1. Linear Accelerators

    CERN Document Server

    Vretenar, M

    2014-01-01

    The main features of radio-frequency linear accelerators are introduced, reviewing the different types of accelerating structures and presenting the main characteristics aspects of linac beam dynamics.

  2. Linear Accelerator (LINAC)

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Linear Accelerator A linear accelerator (LINAC) customizes high energy x-rays to ... ensured? What is this equipment used for? A linear accelerator (LINAC) is the device most commonly used ...

  3. Racetrack linear accelerators

    International Nuclear Information System (INIS)

    An improved recirculating electron beam linear accelerator of the racetrack type is described. The system comprises a beam path of four straight legs with four Pretzel bending magnets at the end of each leg to direct the beam into the next leg of the beam path. At least one of the beam path legs includes a linear accelerator. (UK)

  4. Ant colony method to control variance reduction techniques in the Monte Carlo simulation of clinical electron linear accelerators

    International Nuclear Information System (INIS)

    The ant colony method is used to control the application of variance reduction techniques to the simulation of clinical electron linear accelerators of use in cancer therapy. In particular, splitting and Russian roulette, two standard variance reduction methods, are considered. The approach can be applied to any accelerator in a straightforward way and permits, in addition, to investigate the 'hot' regions of the accelerator, an information which is basic to develop a source model for this therapy tool

  5. Standing wave linear accelerator

    International Nuclear Information System (INIS)

    Consideration is being given to standing wave linear accelerator containing generator, phase shifter, two accelerating resonator sections, charged particle injector and waveguide bridge. Its first arm is oined up with generator via the phase shifter, the second and the third ones-with accelerating sections and the fourth one - with HF-power absorber. HF-power absorber represents a section of circular diaphragmatic wavequide with transformer with input wave and intrawaveguide output load located between injector and the first accelerating section. The section possesses holes in side walls lying on accelerator axis. The distances between centers of the last cell of the fast accelerating section and the first cell of the second accelerating sectiOn equal (2n+3)lambda/4, where n=1, 2, 3..., lambda - wave length of generator. The suggested system enables to improve by one order spectral characteristics of accelerators as compared to the prototype in which magnetrons are used as generator

  6. Software development and clinical application of a multileaf collimator on linear accelerator

    International Nuclear Information System (INIS)

    The use of multi leaf collimator (MLC) to replace conventional field-shaping techniques is not in itself expected to improve the local control of malignancy. the purpose for using MLCs in conventional radiation oncology is to improve the efficiency of treatment delivery. For effective clinical application of MLCs to shaped radiation field, field outline must ne translated into MLC leaf position tables. The intended leaf positions contained in these tables must then be communicated to the control computer that drives the MLC. There are currently at least three techniques utilized by manufacturers of MLCs and treatment planning systems for doing this. The Varian series use a workstation employing a manual digitizer and light box especially. It has a third level MLC configuration and also has the option of placing the wedges above or below the block tray. The C language are used for development of software and three leaf coverage have been used for positioning MLC leaves at the nominal field boundary. The fit of the leaf shape to treatment target volumes are optimized by the rotation of the direction in leaf travel. The clinical application of this software are investigated for Varian MLCs used in linear accelerator of Yonsei Cancer Center. The advantage of the results with using this software is to prescribe and calculate exposed and blocked area in MLCs field. (author)

  7. Determination of dose distributions for clinical linear accelerators using Monte Carlo method in water phantom

    International Nuclear Information System (INIS)

    Different codes were used for Monte Carlo calculations in radiation therapy. In this study, a new Monte Carlo Simulation Program (MCSP) was developed for the effects of the physical parameters of photons emitted from a Siemens Primus clinical linear accelerator (LINAC) on the dose distribution in water. For MCSP, it was written considering interactions of photons with matter. Here, it was taken into account mainly two interactions: The Compton (or incoherent) scattering and photoelectric effect. Photons which come to water phantom surface emitting from a point source were Bremsstrahlung photons. It should be known the energy distributions of these photons for following photons. Bremsstrahlung photons which have 6 MeV (6 MV photon mode) maximum energies were taken into account. In the 6 MV photon mode, the energies of photons were sampled from using Mohan's experimental energy spectrum (Mohan at al 1985). In order to investigate the performance and accuracy of the simulation, measured and calculated (MCSP) percentage depth dose curves and dose profiles were compared. The Monte Carlo results were shown good agreement with experimental measurements.

  8. For Clinical Linear Accelerators, Obtaining of Dose Distributions in Water Phantoms by Using Monte Carlo Methods

    International Nuclear Information System (INIS)

    Different codes were used for Monte Carlo calculations in radiation therapy. In this study, a new Monte Carlo Simulation Program (MCSP) was developed for the effects of the physical parameters of photons emitted from a Siemens Primus clinical linear accelerator (LINAC) on the dose distribution in water. For MCSP, it was written considering interactions of photons with matter. Here, it was taken into account mainly two interactions: The Compton (or incoherent) scattering and photoelectric effect. Photons which come to water phantom surface emitting from a point source were Bremsstrahlung photons. It should be known the energy distributions of these photons for following photons. Bremsstrahlung photons which have 6 MeV (6 MV photon mode) maximum energies were taken into account. In the 6 MV photon mode, the energies of photons were sampled from using Mohan's experimental energy spectrum (Mohan at al 1985). In order to investigate the performance and accuracy of the simulation, measured and calculated (MCSP) percentage depth dose curves and dose profiles were compared. The Monte Carlo results were shown good agreement with experimental measurements.

  9. RF linear accelerators

    CERN Document Server

    Wangler, Thomas P

    2008-01-01

    Thomas P. Wangler received his B.S. degree in physics from Michigan State University, and his Ph.D. degree in physics and astronomy from the University of Wisconsin. After postdoctoral appointments at the University of Wisconsin and Brookhaven National Laboratory, he joined the staff of Argonne National Laboratory in 1966, working in the fields of experimental high-energy physics and accelerator physics. He joined the Accelerator Technology Division at Los Alamos National Laboratory in 1979, where he specialized in high-current beam physics and linear accelerator design and technology. In 2007

  10. Linear induction accelerator

    International Nuclear Information System (INIS)

    This paper examines a new layout for the injector and accelerating sectins of a linear induction accelerator. The sections are combined in a single housing: an induction system with a current-pulse generator based on double strip shaping lines laid over ferromagnetic cores; a multichannel spark discharger with forced current division among channels; and a system for core demagnetization and electron-beam formation and transport. The results of formation of an electron beam in the injector system and its acceleration in the first accelerating section of the accelerator for injection of beams with energies of 0.2-0.4 MeV, currents of 1-2 kA, and pulse durations of 60 nsec are given

  11. Calibration of area monitors for neutrons used in clinical linear accelerators

    International Nuclear Information System (INIS)

    This work demonstrates the complexity and the necessary cares for the realization of measurements of neutron fields in rooms for radiotherapy treatment containing clinical accelerators. The acquaintance of the technical characteristics of the monitors and the periodic calibration are actions and fundamental procedures to guarantee traceability and the reliability of measurements

  12. Application of variance reduction techniques in Monte Carlo simulation of clinical electron linear accelerator

    International Nuclear Information System (INIS)

    Computation time constitutes an important and a problematic parameter in Monte Carlo simulations, which is inversely proportional to the statistical errors so there comes the idea to use the variance reduction techniques. These techniques play an important role in reducing uncertainties and improving the statistical results. Several variance reduction techniques have been developed. The most known are Transport cutoffs, Interaction forcing, Bremsstrahlung splitting and Russian roulette. Also, the use of a phase space seems to be appropriate to reduce enormously the computing time. In this work, we applied these techniques on a linear accelerator (LINAC) using the MCNPX computer Monte Carlo code. This code gives a rich palette of variance reduction techniques. In this study we investigated various cards related to the variance reduction techniques provided by MCNPX. The parameters found in this study are warranted to be used efficiently in MCNPX code. Final calculations are performed in two steps that are related by a phase space. Results show that, comparatively to direct simulations (without neither variance-reduction nor phase space), the adopted method allows an improvement in the simulation efficiency by a factor greater than 700.

  13. Evaluation of neutron doses beyond of primary shielding of rooms housing clinical linear accelerators

    International Nuclear Information System (INIS)

    The growing need to build radiotherapy rooms in places with lack of available space leads to the necessity of unconventional solutions for the shielding projects. In most cases, adding metals to the primary barriers is the best way to shield the rooms properly. However, when photons with energies equal to or great than 10 MeV interact with nuclei of materials with high atomic number, neutrons are ejected and can result in a problem of radioprotection both inside and outside the room. Currently, the only empirical formula existing in the literature to assess the dose equivalent due to neutrons beyond the laminated barriers works only under very specific conditions, and a validation of this formula had not yet been done. In this work, the Monte Carlo code MCNPX was used to verify the validity of the above formula for cases of primary barriers containing lead or iron sheets in rooms that house linear accelerators with 10, 15 and 18 MV. Moreover, such a code was used to evaluate the coefficient of neutron production and tenth-value layer for neutrons in concrete, both parameters that directly influence the equation studied. The study results showed that over 90% of the values compared between the formula and the simulations present discrepancies above 100%, which led to conclude that the formula from the literature produces values that do not match the reality. In addition, there were inconsistencies in the parameters that make up the formula, leading to a need to review this formula in order to build a new model that will better represent the real case. (author)

  14. Introduction to RF linear accelerators

    International Nuclear Information System (INIS)

    The basic features of RF linear accelerators are described. The concept of the 'loaded cavity', essential for the synchronism wave-particle, is introduced, and formulae describing the action of electromagnetic fields on the beam are given. The treatment of intense beams is mentioned, and various existing linear accelerators are presented as examples. (orig.)

  15. Direct reconstruction of the source intensity distribution of a clinical linear accelerator using a maximum likelihood expectation maximization algorithm.

    Science.gov (United States)

    Papaconstadopoulos, P; Levesque, I R; Maglieri, R; Seuntjens, J

    2016-02-01

    Direct determination of the source intensity distribution of clinical linear accelerators is still a challenging problem for small field beam modeling. Current techniques most often involve special equipment and are difficult to implement in the clinic. In this work we present a maximum-likelihood expectation-maximization (MLEM) approach to the source reconstruction problem utilizing small fields and a simple experimental set-up. The MLEM algorithm iteratively ray-traces photons from the source plane to the exit plane and extracts corrections based on photon fluence profile measurements. The photon fluence profiles were determined by dose profile film measurements in air using a high density thin foil as build-up material and an appropriate point spread function (PSF). The effect of other beam parameters and scatter sources was minimized by using the smallest field size ([Formula: see text] cm(2)). The source occlusion effect was reproduced by estimating the position of the collimating jaws during this process. The method was first benchmarked against simulations for a range of typical accelerator source sizes. The sources were reconstructed with an accuracy better than 0.12 mm in the full width at half maximum (FWHM) to the respective electron sources incident on the target. The estimated jaw positions agreed within 0.2 mm with the expected values. The reconstruction technique was also tested against measurements on a Varian Novalis Tx linear accelerator and compared to a previously commissioned Monte Carlo model. The reconstructed FWHM of the source agreed within 0.03 mm and 0.11 mm to the commissioned electron source in the crossplane and inplane orientations respectively. The impact of the jaw positioning, experimental and PSF uncertainties on the reconstructed source distribution was evaluated with the former presenting the dominant effect. PMID:26758232

  16. Direct reconstruction of the source intensity distribution of a clinical linear accelerator using a maximum likelihood expectation maximization algorithm

    Science.gov (United States)

    Papaconstadopoulos, P.; Levesque, I. R.; Maglieri, R.; Seuntjens, J.

    2016-02-01

    Direct determination of the source intensity distribution of clinical linear accelerators is still a challenging problem for small field beam modeling. Current techniques most often involve special equipment and are difficult to implement in the clinic. In this work we present a maximum-likelihood expectation-maximization (MLEM) approach to the source reconstruction problem utilizing small fields and a simple experimental set-up. The MLEM algorithm iteratively ray-traces photons from the source plane to the exit plane and extracts corrections based on photon fluence profile measurements. The photon fluence profiles were determined by dose profile film measurements in air using a high density thin foil as build-up material and an appropriate point spread function (PSF). The effect of other beam parameters and scatter sources was minimized by using the smallest field size (0.5× 0.5 cm2). The source occlusion effect was reproduced by estimating the position of the collimating jaws during this process. The method was first benchmarked against simulations for a range of typical accelerator source sizes. The sources were reconstructed with an accuracy better than 0.12 mm in the full width at half maximum (FWHM) to the respective electron sources incident on the target. The estimated jaw positions agreed within 0.2 mm with the expected values. The reconstruction technique was also tested against measurements on a Varian Novalis Tx linear accelerator and compared to a previously commissioned Monte Carlo model. The reconstructed FWHM of the source agreed within 0.03 mm and 0.11 mm to the commissioned electron source in the crossplane and inplane orientations respectively. The impact of the jaw positioning, experimental and PSF uncertainties on the reconstructed source distribution was evaluated with the former presenting the dominant effect.

  17. 1988 linear accelerator conference proceedings

    International Nuclear Information System (INIS)

    This report contains papers presented at the 1988 Linear Accelerator Conference. A few topics covered are beam dynamics; beam transport; superconducting components; free electron lasers; ion sources; and klystron research

  18. Dosimetric comparison of the linear accelerators at the University Clinic of Radiotherapy and Oncology in Skopje, Macedonia

    International Nuclear Information System (INIS)

    In radiotherapy practice, for various practical reasons it is important to know whether two or more linear accelerators (linacs) are dosimetric matched and whether the patient’s treatment can be shifted from one linac to another without reducing the treatment quality. This work presents the data from the dosimetric comparison of the two Varian Clinacs 23EX and one Varian Clinac iX at the University Clinic of Radiotherapy and Oncology in Skopje. Both Percentage Depth Dose (PDD) and Beam Profile (BP) curves were compared for the photon energies (6MV, 15MV) in use at the clinic. The comparison was performed using the IBA OmniPro Accept 7.4™ software. The results from the comparison of the PDD curves showed that in the clinically significant region the dose differences were smaller than 1%. The results from the comparison of the in line and cross line BP curves showed that in the flattened area the dose differences were smaller than 2.5%, while in the penumbra region they were usually between 2% and 8%, but sometimes up to 21%. This suggests that for treatments where the influence of the penumbra region is small, the three linacs may be considered to be dosimetric matched. For treatments where the influence of the penumbra region is greater, the patient can be switched to another machine only after recalculation of the treatment plan. (Author)

  19. Cast dielectric composite linear accelerator

    Science.gov (United States)

    Sanders, David M.; Sampayan, Stephen; Slenes, Kirk; Stoller, H. M.

    2009-11-10

    A linear accelerator having cast dielectric composite layers integrally formed with conductor electrodes in a solventless fabrication process, with the cast dielectric composite preferably having a nanoparticle filler in an organic polymer such as a thermosetting resin. By incorporating this cast dielectric composite the dielectric constant of critical insulating layers of the transmission lines of the accelerator are increased while simultaneously maintaining high dielectric strengths for the accelerator.

  20. New directions in linear accelerators

    International Nuclear Information System (INIS)

    Current work on linear particle accelerators is placed in historical and physics contexts, and applications driving the state of the art are discussed. Future needs and the ways they may force development are outlined in terms of exciting R and D challenges presented to today's accelerator designers. 23 references, 7 figures

  1. Test accelerator for linear collider

    International Nuclear Information System (INIS)

    KEK has proposed to build Test Accelerator Facility (TAF) capable of producing a 2.5 GeV electron beam for the purpose of stimulating R ampersand D for linear collider in TeV region. The TAF consists of a 1.5 GeV S-band linear accelerator, 1.5 GeV damping ring and 1.0 GeV X-band linear accelerator. The TAF project will be carried forward in three phases. Through Phase-I and Phase-II, the S-band and X-band linacs will be constructed, and in Phase-III, the damping ring will be completed. The construction of TAF Phase-I has started, and the 0.2 GeV S-band injector linac has been almost completed. The Phase-I linac is composed of a 240 keV electron gun, subharmonic bunchers, prebunchers and traveling buncher followed by high-gradient accelerating structures. The SLAC 5045 klystrons are driven at 450 kV in order to obtain the rf-power of 100 MW in a 1 μs pulse duration. The rf-power from a pair of klystrons are combined into an accelerating structure. The accelerating gradient up to 100 MeV/m will be obtained in a 0.6 m long structure. 5 refs., 3 figs., 2 tabs

  2. Estimation of absorbed doses in high energy photon and electron beams from a clinical linear accelerator using extrapolation chamber

    International Nuclear Information System (INIS)

    Calibration of photon and electron beams from a medical linear accelerator is carried out using absorbed dose calibrated gas cavity chambers in water phantoms and applying different international protocols. Bohm and Schneider developed extrapolation chamber (EC), which are specially designed parallel plate ionization chambers capable of measuring accurately the differential specific charge (dq/dm) by varying air mass in cavity by precise control of electrode separation. Zankowski and Podgorsak reported the efficacy of specially built extrapolation chambers as an integral part of po-lystyrene and solid water phantom to measure absorbed in cobalt-60 gamma beam, 4 to 18 MV x-rays and for 6 to 22 MeV electron beams. Mehenna Arib3 reported their experience in performing absolute dosimetry with high energy photon beams using a commercially available Perspex embedded extrapolation chamber and compared with water measurements. If realization of absorbed dose using these chambers is achieved from first principles, this chamber could become a departmental standard. In our institution we do not have standard cobalt-60 machine for determination of Nd, water factors for thimble chambers and no secondary standards laboratory in this country for traceability of our beam level dosimeters. Therefore we investigated the role of extrapolation chamber (EC) for measurement of absorbed doses with clinical radiotherapy beams

  3. Linear Accelerating Superluminal Motion Model

    CERN Document Server

    Zhou, J F; Li, T P; Su, Y; Venturi, T

    2004-01-01

    Accelerating superluminal motions were detected recently by multi-epoch Very Long Baseline Interferometry (VLBI) observations. Here, a Linear Accelerating Superluminal Motion (LASM) model is proposed to interpret the observed phenomena. The model provides a direct and accurate way to estimate the viewing angle of a relativistic jet. It also predicts that both Doppler boosting and deboosting effects may take place in an accelerating forward jet. The LASM model is applied to the data of the quasar 3C 273, and the initial velocity, acceleration and viewing angle of its three components are derived through model fits. The variations of the viewing angle suggest that a supermassive black hole binary system may exist in the center of 3C273. The gap between the inner and outer jet in some radio loud AGNs my be explained in terms of Doppler deboosting effects when the components accelerate to ultra-relativistic speed.

  4. Linear accelerator for radioisotope production

    International Nuclear Information System (INIS)

    A 200- to 500-μA source of 70- to 90-MeV protons would be a valuable asset to the nuclear medicine program. A linear accelerator (linac) can achieve this performance, and it can be extended to even higher energies and currents. Variable energy and current options are available. A 70-MeV linac is described, based on recent innovations in linear accelerator technology; it would be 27.3 m long and cost approx. $6 million. By operating the radio-frequency (rf) power system at a level necessary to produce a 500-μA beam current, the cost of power deposited in the radioisotope-production target is comparable with existing cyclotrons. If the rf-power system is operated at full power, the same accelerator is capable of producing an 1140-μA beam, and the cost per beam watt on the target is less than half that of comparable cyclotrons

  5. drift tube for linear accelerator

    CERN Multimedia

    A drift tube from the Linac 1. This was the first tank of the linear accelerator Linac1, the injection system for the Proton Synchrotron, It ran for 34 years (1958 - 1992). Protons entered at the far end and were accelerated between the copper drift tubes by an oscillating electromagnetic field. The field flipped 200 million times a second (200 MHz) so the protons spent 5 nanoseconds crossing a drift tube and a gap. Moving down the tank, the tubes and gaps had to get longer as the protons gained speed. The tank accelerated protons from 500 KeV to 10 MeV. Linac1 was also used to accelerate deutrons and alpha particles for the Intersecting Storage Rings and oxygen and sulpher ions for the Super Proton Synchrotron heavy ion programme.

  6. Extrapolation chamber mounted on perspex for calibration of high energy photon and electron beams from a clinical linear accelerator

    Directory of Open Access Journals (Sweden)

    Ravichandran R

    2009-01-01

    Full Text Available The objective of the present study is to establish radiation standards for absorbed doses, for clinical high energy linear accelerator beams. In the nonavailability of a cobalt-60 beam for arriving at Nd, water values for thimble chambers, we investigated the efficacy of perspex mounted extrapolation chamber (EC used earlier for low energy x-rays and beta dosimetry. Extrapolation chamber with facility for achieving variable electrode separations 10.5mm to 0.5mm using micrometer screw was used for calibrations. Photon beams 6 MV and 15 MV and electron beams 6 MeV and 15 MeV from Varian Clinac linacs were calibrated. Absorbed Dose estimates to Perspex were converted into dose to solid water for comparison with FC 65 ionisation chamber measurements in water. Measurements made during the period December 2006 to June 2008 are considered for evaluation. Uncorrected ionization readings of EC for all the radiation beams over the entire period were within 2% showing the consistency of measurements. Absorbed doses estimated by EC were in good agreement with in-water calibrations within 2% for photons and electron beams. The present results suggest that extrapolation chambers can be considered as an independent measuring system for absorbed dose in addition to Farmer type ion chambers. In the absence of standard beam quality (Co-60 radiations as reference Quality for Nd,water the possibility of keeping EC as Primary Standards for absorbed dose calibrations in high energy radiation beams from linacs should be explored. As there are neither Standard Laboratories nor SSDL available in our country, we look forward to keep EC as Local Standard for hospital chamber calibrations. We are also participating in the IAEA mailed TLD intercomparison programme for quality audit of existing status of radiation dosimetry in high energy linac beams. The performance of EC has to be confirmed with cobalt-60 beams by a separate study, as linacs are susceptible for minor

  7. Estimation of absorbed dose in clinical radiotherapy linear accelerator beams: effect of ion chamber calibration and long-term stability

    International Nuclear Information System (INIS)

    The measured dose in water at reference point in phantom is a primary parameter for planning the treatment monitor units (MU); both in conventional and intensity modulated/image guided treatments. Traceability of dose accuracy therefore still depends mainly on the calibration factor of the ion chamber/dosimeter provided by the accredited Secondary Standard Dosimetry Laboratories (SSDLs), under International Atomic Energy Agency (IAEA) network of laboratories. The data related to Nd,water calibrations, thermoluminescent dosimetry (TLD) postal dose validation, inter-comparison of different dosimeter/electrometers, and validity of Nd,water calibrations obtained from different calibration laboratories were analyzed to find out the extent of accuracy achievable. Nd,w factors in Gray/Coulomb calibrated at IBA, GmBH, Germany showed a mean variation of about 0.2% increase per year in three Farmer chambers, in three subsequent calibrations. Another ion chamber calibrated in different accredited laboratory (PTW, Germany) showed consistent Nd,w for 9 years period. The Strontium-90 beta check source response indicated long-term stability of the ion chambers within 1% for three chambers. Results of IAEA postal TL 'dose intercomparison' for three photon beams, 6 MV (two) and 15 MV (one), agreed well within our reported doses, with mean deviation of 0.03% (SD 0.87%) (n = 9). All the chamber/electrometer calibrated by a single SSDL realized absorbed doses in water within 0.13% standard deviations. However, about 1-2% differences in absorbed dose estimates observed when dosimeters calibrated from different calibration laboratories are compared in solid phantoms. Our data therefore imply that the dosimetry level maintained for clinical use of linear accelerator photon beams are within recommended levels of accuracy and uncertainities are within reported values. (author)

  8. Seismic response of linear accelerators

    OpenAIRE

    Collette, Christophe; Artoos, Kurt; Guinchard, Michael; Hauviller, Claude

    2010-01-01

    This paper is divided into two parts. The first part presents recent measurements of ground motion in the LHC tunnel at CERN. From these measurements, an update of the ground motion model currently used in accelerator simulations is presented. It contains new features like a model of the lateral motion and the technical noise. In the second part, it is shown how this model can be used to evaluate the seismic response of a linear accelerator in the frequency domain. Then, the approach is valid...

  9. Calibration of area monitors for neutrons used in clinical linear accelerators; Calibracao de monitores de area para neutrons usados em aceleradores lineares clinicos

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, Ana Paula; Pereira, Walsan Wagner; Patrao, Karla C. de Souza; Fonseca, Evaldo S. da, E-mail: asalgado@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Batista, Delano V.S. [Instituto Nacional do Cancer (INCa), Rio de Janeiro, RJ (Brazil)

    2009-07-01

    This work demonstrates the complexity and the necessary cares for the realization of measurements of neutron fields in rooms for radiotherapy treatment containing clinical accelerators. The acquaintance of the technical characteristics of the monitors and the periodic calibration are actions and fundamental procedures to guarantee traceability and the reliability of measurements

  10. Linear induction accelerator parameter options

    International Nuclear Information System (INIS)

    The principal undertaking of the Beam Research Program over the past decade has been the investigation of propagating intense self-focused beams. Recently, the major activity of the program has shifted toward the investigation of converting high quality electron beams directly to laser radiation. During the early years of the program, accelerator development was directed toward the generation of very high current (>10 kA), high energy beams (>50 MeV). In its new mission, the program has shifted the emphasis toward the production of lower current beams (>3 kA) with high brightness (>106 A/(rad-cm)2) at very high average power levels. In efforts to produce these intense beams, the state of the art of linear induction accelerators (LIA) has been advanced to the point of satisfying not only the current requirements but also future national needs

  11. Linear Accelerator Simulations with BMAD

    CERN Document Server

    Urban, Jeremy; Sagan, David

    2005-01-01

    BMAD is a subroutine library for simulating relativistic charged-particle dynamics. It has been used extensively as a diagnostic tool at the Cornell Electron Storage Ring (CESR). The BMAD libraries have recently been extended to include modeling of the dynamics of linear accelerators. Calculations of emittance dilution due to orbit offsets and misalignments have been compared with LIAR, Merlin and PLACET, and good agreement is found with both particle and macroparticle tracking through the NLC and Tesla lattices for the bunch compressor, main linac and final focus regions.

  12. Development of a postal system for dosimetry quality control performed in photon beams produced by linear accelerators of clinical use

    International Nuclear Information System (INIS)

    In this work a different system is proposed which is able to verify the absorbed depth dose given at two different depths, the irradiation field homogeneity and its coincidence with the light field of the machine, the source to surface distance used and the beam nominal energy. These radiation field parameters are very important in the tumour treatment and they may help in the determination of the error sources of the absorbed depth dose. The system developed uses a water phantom, LiF thermoluminescent dosemeters and a radiographic film to evaluate such parameters. The postal system developed in this work has been tested in linear accelerators of 4 to 18 MV with good results. (author)

  13. Superconducting linear accelerator system for NSC

    Indian Academy of Sciences (India)

    P N Prakash; T S Datta; B P Ajith Kumar; J Antony; P Barua; J Chacko; A Choudhury; G K Chadhari; S Ghosh; S Kar; S A Krishnan; Manoj Kumar; Rajesh Kumar; A Mandal; D S Mathuria; R S Meena; R Mehta; K K Mistri; A Pandey; M V Suresh Babu; B K Sahu; A Sarkar; S S K Sonti; A Rai; S Venkatramanan; J Zacharias; R K Bhowmik; A Roy

    2002-11-01

    This paper reports the construction of a superconducting linear accelerator as a booster to the 15 UD Pelletron accelerator at Nuclear Science Centre, New Delhi. The LINAC will use superconducting niobium quarter wave resonators as the accelerating element. Construction of the linear accelerator has progressed sufficiently. Details of the entire accelerator system including the cryogenics facility, RF electronics development, facilities for fabricating niobium resonators indigenously, and present status of the project are presented.

  14. Terahertz-driven linear electron acceleration

    CERN Document Server

    Nanni, Emilio Alessandro; Ravi, Koustuban; Fallahi, Arya; Moriena, Gustavo; Miller, R J Dwayne; Kärtner, Franz X

    2014-01-01

    The cost, size and availability of electron accelerators is dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency (RF) accelerating structures operate with 30-50 MeV/m gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional RF structures. However, laser-driven electron accelerators require intense sources and suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here, we demonstrate the first linear acceleration of electrons with keV energy gain using optically-generated terahertz (THz) pulses. THz-driven accelerating structures enable high-gradient electron accelerators with simple accelerating structures, high repetition rates and significant charge per bunch. Increasing the operational frequency of accelerators into the THz band allows for greatly increased accelerating ...

  15. Electron linear accelerator for industrial radiography

    International Nuclear Information System (INIS)

    The report presents full description of the design, construction and running up of prototype of 4 MeV electron linear accelerator. The principles of operation and the construction of various parts of the accelerator together with their functional links are also given. The accelerator is destined for radiographic control of materials and industrial goods. 21 refs., 23 figs. (author)

  16. Parallel beam dynamics simulation of linear accelerators

    OpenAIRE

    Qiang, Ji; Ryne, Robert D.

    2002-01-01

    In this paper we describe parallel particle-in-cell methods for the large scale simulation of beam dynamics in linear accelerators. These techniques have been implemented in the IMPACT (Integrated Map and Particle Accelerator Tracking) code. IMPACT is being used to study the behavior of intense charged particle beams and as a tool for the design of next-generation linear accelerators. As examples, we present applications of the code to the study of emittance exchange in high intensity b...

  17. Linear accelerator for tritium production

    International Nuclear Information System (INIS)

    For many years now, Los Alamos National Laboratory has been working to develop a conceptual design of a facility for accelerator production of tritium (APT). The APT accelerator will produce high energy protons which will bombard a heavy metal target, resulting in the production of large numbers of spallation neutrons. These neutrons will be captured by a low-Z target to produce tritium. This paper describes the latest design of a room-temperature, 1.0 GeV, 100 mA, cw proton accelerator for tritium production. The potential advantages of using superconducting cavities in the high-energy section of the linac are also discussed and a comparison is made with the baseline room-temperature accelerator. copyright 1996 American Institute of Physics

  18. Linear accelerator for tritium production

    International Nuclear Information System (INIS)

    For many years now, Los Alamos National Laboratory has been working to develop a conceptual design of a facility for accelerator production of tritium (API). The APT accelerator will produce high energy protons which will bombard a heavy metal target, resulting in the production of large numbers of spallation neutrons. These neutrons will be captured by a low-Z target to produce tritium. This paper describes the latest design of a room-temperature, 1.0 GeV, 100 mA, cw proton accelerator for tritium production. The potential advantages of using superconducting cavities in the high-energy section of the linac are also discussed and a comparison is made with the baseline room-temperature accelerator

  19. Automating linear accelerator quality assurance

    Energy Technology Data Exchange (ETDEWEB)

    Eckhause, Tobias; Thorwarth, Ryan; Moran, Jean M., E-mail: jmmoran@med.umich.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan 48109-5010 (United States); Al-Hallaq, Hania; Farrey, Karl [Department of Radiation Oncology and Cellular Oncology, The University of Chicago, Chicago, Illinois 60637 (United States); Ritter, Timothy [Ann Arbor VA Medical Center, Ann Arbor, Michigan 48109 (United States); DeMarco, John [Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, California, 90048 (United States); Pawlicki, Todd; Kim, Gwe-Ya [UCSD Medical Center, La Jolla, California 92093 (United States); Popple, Richard [Department of Radiation Oncology, University of Alabama Birmingham, Birmingham, Alabama 35249 (United States); Sharma, Vijeshwar; Park, SungYong [Karmanos Cancer Institute, McLaren-Flint, Flint, Michigan 48532 (United States); Perez, Mario; Booth, Jeremy T. [Royal North Shore Hospital, Sydney, NSW 2065 (Australia)

    2015-10-15

    Purpose: The purpose of this study was 2-fold. One purpose was to develop an automated, streamlined quality assurance (QA) program for use by multiple centers. The second purpose was to evaluate machine performance over time for multiple centers using linear accelerator (Linac) log files and electronic portal images. The authors sought to evaluate variations in Linac performance to establish as a reference for other centers. Methods: The authors developed analytical software tools for a QA program using both log files and electronic portal imaging device (EPID) measurements. The first tool is a general analysis tool which can read and visually represent data in the log file. This tool, which can be used to automatically analyze patient treatment or QA log files, examines the files for Linac deviations which exceed thresholds. The second set of tools consists of a test suite of QA fields, a standard phantom, and software to collect information from the log files on deviations from the expected values. The test suite was designed to focus on the mechanical tests of the Linac to include jaw, MLC, and collimator positions during static, IMRT, and volumetric modulated arc therapy delivery. A consortium of eight institutions delivered the test suite at monthly or weekly intervals on each Linac using a standard phantom. The behavior of various components was analyzed for eight TrueBeam Linacs. Results: For the EPID and trajectory log file analysis, all observed deviations which exceeded established thresholds for Linac behavior resulted in a beam hold off. In the absence of an interlock-triggering event, the maximum observed log file deviations between the expected and actual component positions (such as MLC leaves) varied from less than 1% to 26% of published tolerance thresholds. The maximum and standard deviations of the variations due to gantry sag, collimator angle, jaw position, and MLC positions are presented. Gantry sag among Linacs was 0.336 ± 0.072 mm. The

  20. Automating linear accelerator quality assurance

    International Nuclear Information System (INIS)

    Purpose: The purpose of this study was 2-fold. One purpose was to develop an automated, streamlined quality assurance (QA) program for use by multiple centers. The second purpose was to evaluate machine performance over time for multiple centers using linear accelerator (Linac) log files and electronic portal images. The authors sought to evaluate variations in Linac performance to establish as a reference for other centers. Methods: The authors developed analytical software tools for a QA program using both log files and electronic portal imaging device (EPID) measurements. The first tool is a general analysis tool which can read and visually represent data in the log file. This tool, which can be used to automatically analyze patient treatment or QA log files, examines the files for Linac deviations which exceed thresholds. The second set of tools consists of a test suite of QA fields, a standard phantom, and software to collect information from the log files on deviations from the expected values. The test suite was designed to focus on the mechanical tests of the Linac to include jaw, MLC, and collimator positions during static, IMRT, and volumetric modulated arc therapy delivery. A consortium of eight institutions delivered the test suite at monthly or weekly intervals on each Linac using a standard phantom. The behavior of various components was analyzed for eight TrueBeam Linacs. Results: For the EPID and trajectory log file analysis, all observed deviations which exceeded established thresholds for Linac behavior resulted in a beam hold off. In the absence of an interlock-triggering event, the maximum observed log file deviations between the expected and actual component positions (such as MLC leaves) varied from less than 1% to 26% of published tolerance thresholds. The maximum and standard deviations of the variations due to gantry sag, collimator angle, jaw position, and MLC positions are presented. Gantry sag among Linacs was 0.336 ± 0.072 mm. The

  1. Treatment planning optimization for linear accelerator radiosurgery

    International Nuclear Information System (INIS)

    Purpose: Linear accelerator radiosurgery uses multiple arcs delivered through circular collimators to produce a nominally spherical dose distribution. Production of dose distributions that conform to irregular lesions or conformally avoid critical neural structures requires a detailed understanding of the available treatment planning parameters. Methods and Materials: Treatment planning parameters that may be manipulated within a single isocenter to provide conformal avoidance and dose conformation to ellipsoidal lesions include differential arc weighting and gantry start/stop angles. More irregular lesions require the use of multiple isocenters. Iterative manipulation of treatment planning variables can be difficult and computationally expensive, especially if the effects of these manipulations are not well defined. Effects of treatment parameter manipulation are explained and illustrated. This is followed by description of the University of Florida Stereotactic Radiosurgery Treatment Planning Algorithm. This algorithm organizes the manipulations into a practical approach for radiosurgery treatment planning. Results: Iterative treatment planning parameters may be efficiently manipulated to achieve optimal treatment plans by following the University of Florida Treatment Planning Algorithm. The ability to produce conformal stereotactic treatment plans using the algorithm is demonstrated for a variety of clinical presentations. Conclusion: The standard dose distribution produced in linear accelerator radiosurgery is spherical, but manipulation of available treatment planning parameters may result in optimal dose conformation. The University of Florida Treatment Planning Algorithm organizes available treatment parameters to efficiently produce conformal radiosurgery treatment plans

  2. Terahertz-driven linear electron acceleration

    Science.gov (United States)

    Nanni, Emilio A.; Huang, Wenqian R.; Hong, Kyung-Han; Ravi, Koustuban; Fallahi, Arya; Moriena, Gustavo; Dwayne Miller, R. J.; Kärtner, Franz X.

    2015-10-01

    The cost, size and availability of electron accelerators are dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency accelerating structures operate with 30-50 MeV m-1 gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional radio-frequency structures. However, laser-driven wakefield accelerators require intense femtosecond sources and direct laser-driven accelerators suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here we demonstrate linear acceleration of electrons with keV energy gain using optically generated terahertz pulses. Terahertz-driven accelerating structures enable high-gradient electron/proton accelerators with simple accelerating structures, high repetition rates and significant charge per bunch. These ultra-compact terahertz accelerators with extremely short electron bunches hold great potential to have a transformative impact for free electron lasers, linear colliders, ultrafast electron diffraction, X-ray science and medical therapy with X-rays and electron beams.

  3. Elementary principles of linear accelerators

    International Nuclear Information System (INIS)

    These lectures come in five sections. The first is this introduction. The second is a short chronology of what are viewed as important milestones in the field. The third covers proton linacs. It introduces elementary concepts such as transit time, shunt impedance, and Q. Critical issues such as phase stability and transverse forces are discussed. The fourth section contains an elementary discussion of waveguide accelerating structures. It can be regarded as an introduction to some of the more advanced treatments of the subject. The final section is devoted to electron accelerators. Taking SLAC as an example, various topics are discussed such as structure design, choice of parameters, frequency optimization, beam current, emittance, bunch length and beam loading. Recent developments and future challenges are mentioned briefly. 41 figures, 4 tables

  4. Possibilities for linear waveguide accelerator efficiency increase

    International Nuclear Information System (INIS)

    Problems connected with increasing the efficiency of an intense electron beam interaction with the accelerating electromagnetic field in linear waveguide accelerators are considered. Here the expression for the accelerating electromagnetic field is written as the sum of fields of the generator and the radiation, obtained in the most general case with regard to the slip between the particle clusters and the wave of the radiation field. Comparison between the obtained theoretical values and experimental data for some operating accelerators allows us to conclude on the possibility for designating the more efficient accelerators. It is shown that the limiting values of current in accelerators with exponential dependence of conductivity along a section can be higher than in those with constant or linear dependence

  5. Linear accelerator breeder for energy security

    International Nuclear Information System (INIS)

    The possibility of using linear accelerators for the breeding of fissile fuels to ensure energy security is discussed. The mechanisms of the nuclear reactions producing uranium-233 and plutonium-239 are described, and neutron yields for various particle beams on a uranium target are given. Design concepts for linear accelerators for breeding and target assemblies are outlined, and estimated capital and operating costs are given

  6. Booster linear accelerators for proton therapy

    International Nuclear Information System (INIS)

    Radiotherapy using proton beams of energies of order 200 MeV is now accepted as a feasible cancer treatment technique whose widespread use has so far been limited by the high costs of proposed facilities. AEA Technology have identified a low-cost solution using a linear accelerator to boost existing hospital cyclotrons. The present project status and the design of the booster linear accelerator are discussed. (Author) 4 tabs., 2 figs., 2 refs

  7. Notes on beam dynamics in linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Gluckstern, R.L.

    1980-09-01

    A collection of notes, on various aspects of beam dynamics in linear accelerators, which were produced by the author during five years (1975 to 1980) of consultation for the LASL Accelerator Technology (AT) Division and Medium-Energy Physics (MP) Division is presented.

  8. Effective acceptance evaluation of linear resonance accelerator

    International Nuclear Information System (INIS)

    One of the most important challenges for accelerators is to match an accelerating beam with an accelerator acceptance. It allows one reduce a particle loss. Effective acceptance evaluation of linear resonance accelerator with RF focusing is carried out with no taking into account a beam space charge; a model taking into account non-coherent bunch particle oscillations is considered with the use of an averaging technique over rapid oscillations. Analytical results obtained are verified. Computer simulations of self-consistent low-energy ion beam dynamics are performed.

  9. Clinical Experiences With Onboard Imager KV Images for Linear Accelerator-Based Stereotactic Radiosurgery and Radiotherapy Setup

    International Nuclear Information System (INIS)

    Purpose: To report our clinical experiences with on-board imager (OBI) kV image verification for cranial stereotactic radiosurgery (SRS) and radiotherapy (SRT) treatments. Methods and Materials: Between January 2007 and May 2008, 42 patients (57 lesions) were treated with SRS with head frame immobilization and 13 patients (14 lesions) were treated with SRT with face mask immobilization at our institution. No margin was added to the gross tumor for SRS patients, and a 3-mm three-dimensional margin was added to the gross tumor to create the planning target volume for SRT patients. After localizing the patient with stereotactic target positioner (TaPo), orthogonal kV images using OBI were taken and fused to planning digital reconstructed radiographs. Suggested couch shifts in vertical, longitudinal, and lateral directions were recorded. kV images were also taken immediately after treatment for 21 SRS patients and on a weekly basis for 6 SRT patients to assess any intrafraction changes. Results: For SRS patients, 57 pretreatment kV images were evaluated and the suggested shifts were all within 1 mm in any direction (i.e., within the accuracy of image fusion). For SRT patients, the suggested shifts were out of the 3-mm tolerance for 31 of 309 setups. Intrafraction motions were detected in 3 SRT patients. Conclusions: kV imaging provided a useful tool for SRS or SRT setups. For SRS setup with head frame, it provides radiographic confirmation of localization using the stereotactic target positioner. For SRT with mask, a 3-mm margin is adequate and feasible for routine setup when TaPo is combined with kV imaging

  10. Next linear collider test accelerator injector upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Yeremian, A.D.; Miller, R.H. [Stanford Linear Accelerator Center, CA (United States)

    1995-12-31

    The Next Linear Collider Test Accelerator (NLCTA) is being constructed at SLAC to demonstrate multibunch beam loading compensation, suppression of higher order deflecting modes and measure transverse components of the accelerating fields in X-band accelerating structures. Currently a simple injector which provides the average current necessary for the beam loading compensations studies is under construction. An injector upgrade is planned to produce bunch trains similar to that of the NLC with microbunch intensity, separation and energy spread, identical to that of NLC. We discuss the design of the NLCTA injector upgrade.

  11. Distributed coupling high efficiency linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Tantawi, Sami G.; Neilson, Jeffrey

    2016-07-19

    A microwave circuit for a linear accelerator includes multiple monolithic metallic cell plates stacked upon each other so that the beam axis passes vertically through a central acceleration cavity of each plate. Each plate has a directional coupler with coupling arms. A first coupling slot couples the directional coupler to an adjacent directional coupler of an adjacent cell plate, and a second coupling slot couples the directional coupler to the central acceleration cavity. Each directional coupler also has an iris protrusion spaced from corners joining the arms, a convex rounded corner at a first corner joining the arms, and a corner protrusion at a second corner joining the arms.

  12. Stability of non-linear integrable accelerator

    OpenAIRE

    Batalov, I.; Valishev, A.

    2012-01-01

    The stability of non-linear Integrable Optics Test Accelerator (IOTA) model was tested. The area of the stable region in transverse coordinates and the maximum attainable tune spread were found as a function of non-linear lens strength. Particle loss as a function of turn number was analyzed to determine whether a dynamic aperture limitation present in the system. The system was also tested with sextupoles included in the machine for chromaticity compensation. A method of evaluation of the be...

  13. Accelerating Dense Linear Algebra on the GPU

    DEFF Research Database (Denmark)

    Sørensen, Hans Henrik Brandenborg

    and matrix-vector operations on GPUs. Such operations form the backbone of level 1 and level 2 routines in the Basic Linear Algebra Subroutines (BLAS) library and are therefore of great importance in many scientific applications. The target hardware is the most recent NVIDIA Tesla 20-series (Fermi...... architecture). Most of the techniques I discuss for accelerating dense linear algebra are applicable to memory-bound GPU algorithms in general....

  14. Nanosecond pulse generators for induction linear accelerators

    International Nuclear Information System (INIS)

    The paper reviews five different circuits of nanosecond pulse generators for induction linear accelerators. Hydrogen thyratrons which feature a good stability of parameters in time are used as switches. Short voltage pulses (1 - 5 ns) are shaped using nonlinear ferromagnetic lines.The voltage amplitude range on inductor excitation turns is 20-50 kV. 6 refs., 6 figs., 1 tab

  15. Proceedings of the 1981 linear accelerator conference

    International Nuclear Information System (INIS)

    The 1981 Linear Accelerator Conference was held at Bishop's Lodge, Santa Fe, New Mexico, October 19-23, 1981. This publication contains the texts of the invited and contributed papers. Abstracts of individual items from the conference were prepared separately for the data base

  16. Linear collider accelerator physics issues regarding alignment

    International Nuclear Information System (INIS)

    The next generation of linear colliders will require more stringent alignment tolerances than those for the SLC with regard to the accelerating structures, quadrupoles, and beam position monitors. New techniques must be developed to achieve these tolerances. A combination of mechanical-electrical and beam-based methods will likely be needed

  17. Calibration of an Electron Linear Accelerator using an acrylic puppet

    International Nuclear Information System (INIS)

    The finality of this work is to find the dose for electron beams using acrylic puppets and inter comparing with the measurements in water, found also its respective conversion factor. With base in this, its may be realize interesting measurements for the good performance of a linear accelerator and special clinical treatments in less time. (Author)

  18. CLIA - a Compact Linear Induction Accelerator System

    International Nuclear Information System (INIS)

    CLIA (Compact Linear Induction Accelerator) is a 750 kV, 10 kA, 60 ns, 200 Hz pulse generator that has been designed, constructed, and operated at Physics International. The CLIA system consists of (from the load back to the mains) a ten-cell linear induction voltage adder, ten magnetically switched water insulated pulse forming lines (PFL's), a two-stage Magnetic Compression Unit (MCU), and thyratron-switched Intermediate Energy Store (IES), and Command Resonant Charge (CRC) units. This system was conceived to drive repetitive e-beam loads for various types of repetitive testing. A linear induction accelerator system was used because it allows all pulse compression to be done at moderate voltage (40 to 150 kV) and then uses the accelerator structure to add parallel voltage pulses into a single high voltage output (750 kV). Nowhere except at the load does a voltage of higher than 150 kV appear. This allows the switching to be done at moderate voltage and the use of hydrogen thyratrons and magnetic switches is possible. This generator has been in operation at Physics International for over a year and has achieved all its design goals. The design and operational characteristics of the accelerator will be described in this paper

  19. Linear accelerator with radial lines - LIA-30

    International Nuclear Information System (INIS)

    Multimodule linear induction 40 MeV accelerator on radial lines with distributed parameters, a powerful generator of bremsstrahlung radiation, is briefly described. More than 2000 controlled spark switches commutate low-impedance inductor lines according to a specified program at nanosecond accuracy. The electron beam of up to 100 kA current is transported in the external longitudinal magnetic field over the beamline 25 m long. Some research results in optimization of the conditions for annular electron beam transportation and feasibility of various acceleration regimes are noted

  20. Perception of linear acceleration in weightlessness

    Science.gov (United States)

    Arrott, Anthony P.; Young, Laurence R.; Merfeld, Daniel M.

    1991-01-01

    Tests of the perception and use of linear acceleration sensory information were performed on the science crews of the Spacelab 1 (SL-1) and D-1 missions using linear 'sleds' in-flight (D-1) and pre-post flight. The time delay between the acceleration step stimulus and the subjective response was consistently reduced during weightlessness, but was neither statistically significant nor of functional importance. Increased variability of responses when going from one environment to the other was apparent from measurements on the first day of the mission and in the first days post-flight. Subjective reports of perceived motion during sinusoidal oscillation in weightlessness were qualitatively similar to reports on earth. In a closed-loop motion nulling task, enhanced performance was observed post-flight in all crewmembers tested in the Y or Z axes.

  1. Radiation load of workers on linear accelerators

    International Nuclear Information System (INIS)

    Burden of health care personnel working on linear accelerators. New examination and treatment methods enable to reduce the number of health care personnel even in the case of increased numbers of examined patients. However, still open is the question of determining the effective dose delivered to health care personnel. The employment of several methods of evaluation of received dose at one workplace makes it possible to compare the accuracy and reliability of the respective types of measuring devices, as well as to point out the pitfalls of their use.At the St. Elizabeth Cancer Institute we compared the results of measurements of TL dosimeters, and OSL dosimeters at workplaces with linear accelerators. (authors)

  2. Dragon-I Linear Induction Electron Accelerator

    International Nuclear Information System (INIS)

    Dragon-I is a linear induction electron accelerator. This facility consists of a 3.6 MeV injector, 38 meter beam transport line and 16 MeV induction accelerator powered by high voltage generators, including 8 Marx generators and 48 Blumlein lines. This paper describes the physics design, development and experimental results of Dragon-I. The key technology is analyzed in the accelerator development, and the design requirements and operation of the major subsystems are presented. The experimental results show Dragon-I generates an 18-20 MeV, 2.5 kA, 70 ns electron beam. The X-ray spot size is about 1.2 mm and dose level about 0.103 C/kg at 1 meter. (authors)

  3. Risk analysis of linear accelerator radiosurgery

    International Nuclear Information System (INIS)

    Purpose: To evaluate the toxicity of stereotactic single-dose irradiation and to compare the own results with already existing risk prediction models. Methods and Materials: Computed tomography (CT) or magnetic-resonance (MR) images, and clinical data of 133 consecutive patients treated with linear accelerator radiosurgery were analyzed retrospectively. Using the Cox proportional hazards model the relevance of treatment parameters and dose-volume relationships on the occurrence of radiation-induced tissue changes (edema, localized blood-brain barrier breakdown) were assessed. Results: Sixty-two intraparenchymal lesions (arteriovenous malformation (AVM): 56 patients, meningioma: 6 patients) and 73 skull base tumors were selected for analysis. The median follow-up was 28.1 months (range: 9.0-58.9 months). Radiation-induced tissue changes (32 out of 135, 23.7%) were documented on CT or MR images 3.6-58.7 months after radiosurgery (median time: 17.8 months). The actuarial risk at 2 years for the development of neuroradiological changes was 25.8% for all evaluated patients, 38.4% for intraparenchymal lesions, and 14.6% for skull base tumors. The coefficient: total volume receiving a minimum dose of 10 Gy (VTREAT10) reached statistical significance in a Cox proportional hazards model calculated for all patients, intraparenchymal lesions, and AVMs. In skull base tumors, the volume of normal brain tissue covered by the 10 Gy isodose line (VBRAIN10) was the only significant variable. Conclusions: These results demonstrate the particular vulnerability of normal brain tissue to single dose irradiation. Optimal conformation of the therapeutic isodose line to the 3D configuration of the target volume may help to reduce side effects

  4. Clinical analysis of linear accelerator radiosurgery for 42 cases with trigeminal neuralgia%X刀治疗三叉神经痛42例临床分析

    Institute of Scientific and Technical Information of China (English)

    陈苏; 王如密; 王守森

    2008-01-01

    Objective To study the treatment effect of linear accelerator radiosurgery (X knife) on trigeminal neuralgia and the complications. Methods Follow-up was conducted in 42 cases of trigeminal neuralgia treated with linear accelerator radiosurgery in our department, and their complications and degree of pain relief were recorded. Results Outcomes were excellent in 14 (33.3%), good in 22 (52.4%), effective in 4 (9.5%) and poor in 2 (4.8%). The mean time of pain relief was 2.1 months. Seven (16.7%) cases experienced increased facial paresthesia. Conclusion Linear accelerator radiosurgery is a precise and effective treatment for trigeminal neuralgia.%目的 探讨直线加速器放射外科(X 刀)治疗三叉神经痛的疗效及其并发症.方法 回顾性分析我科收治的42例三叉神经痛患者的临床资料,均采用X刀治疗并随访疼痛缓解情况和并发症.结果 本组治疗效果为治愈14例(33.3%).显效22例(52.4%),有效4例(9.5%),无效2例(4.8%).疼痛缓解出现时间平均在2.1月之后.7例(16.7%)术后出现面部麻木.结论 X刀是一种精确而有效的治疗三叉神经痛的方法.

  5. LIONs at the Stanford Linear Accelerator Center

    International Nuclear Information System (INIS)

    The term LION is an acronym for Long Ionization Chamber. This is a distributed ion chamber which is used to monitor secondary ionization along the shield walls of a beam line resulting from incorrectly steered charged particle beams in lieu of the use of many discrete ion chambers. A cone of ionizing radiation emanating from a point source as a result of incorrect steering intercepts a portion of 1-5/8 inch Heliax cable (about 100 meters in length) filled with Argon gas at 20 psi and induces a pulsed current which is proportional to the ionizing charge. This signal is transmitted via the cable to an integrator circuit whose output is directed to an electronic comparators, which in turn is used to turn off the accelerated primary beam when preset limits are exceeded. This device is used in the Stanford Linear Accelerator Center (SLAC) Beam Containment System (BCS) to prevent potentially hazardous ionizing radiation resulting from incorrectly steered beams in areas that might be occupied by people. This paper describes the design parameters and experience in use in the Final Focus Test Beam (FFTB) area of the Stanford Linear Accelerator Center

  6. Seventh International Accelerator School for Linear Colliders

    CERN Multimedia

    Organizers of the Seventh International Accelerator School for Linear Colliders

    2012-01-01

    We are pleased to announce the Seventh International Accelerator School for Linear Colliders. This school is a continuation of the series of schools which began six years ago.  The first school was held in 2006 in Sokendai, Japan, the second in 2007 in Erice, Italy, the third in 2008 in Oakbrook Hills, USA, the fourth in 2009 in Huairou, China, the fifth in 2010 in Villars-sur-Ollon, Switzerland, and the sixth in 2011 in Pacific Grove, USA.   The school is organized by the International Linear Collider (ILC) Global Design Effort (GDE), the Compact Linear Collider (CLIC) and the International Committee for Future Accelerators (ICFA) Beam Dynamics Panel. The school this year will take place at the Radisson Blu Hotel, Indore, India from November 27 to December 8, 2012. It is hosted by the Raja Ramanna Center for Advanced Technology (RRCAT) and sponsored by a number of funding agencies and institutions around the world including the U.S. Department of Energy (DOE), the U.S. National Science...

  7. Linear accelerator for burner-reactor

    International Nuclear Information System (INIS)

    Future development of nuclear power engineering depends on the successful solution of two key problems of safety and utilization of high level radioactive wastes (HLRW) of atomic power plants (APP). Modern methods of HLRW treatment involve solidification, preliminary storing for a period of 30-50 years necessary for the decay of long-living nuclides and final burial in geological formations several hundred meters below the ground surface. The depth burial of the radioactive wastes requires complicated under ground constructions. It's very expensive and doesn't meet modern ecological requirements. Alternative modern and more reasonable methods of APP HLRW treatment are under consideration now. One of the methods involves separation of APP waste radionuclides for use in economy with subsequent transmutation of the long-living isotopes into the short-living ones by high-intensity neutron fluxes generated by proton accelerators. The installation intended for the long-living radionuclides transmutation into the short-living ones is called burner-reactor. It can be based on the continuous regime proton accelerator with 1.5 GeV energy, 0.3 A current and beam mean power of 450 MW. The preferable type of the proton accelerator with the aforementioned parameters is the linear accelerator

  8. An injection system for a linear accelerator

    International Nuclear Information System (INIS)

    An injection system for the Linear Accelerator is developed using the parameters of machines at the Centro Brasileiro de Pesquisas Fisicas and the Instituto Militar de Engenharia. The proposed system consists basically of a prebuncher and a chopper. The pre-buncher is used to improve the energy resolution and also to increase the accelerator target current. The chopper is used to remove from the beam the electrons that have no possibility of attaining the desired energy and that are usually lost in the walls and the cavity tube, thus producing undesirable background. Theoretical development of the chopper is performed in order to obtain its dimensions for future construction. The complete design the pre-buncher and its feed supply system and the experimental verication of its performance are also presented. It is intended to give the necessary information for the design and construction of the complete injection system proposed. (Author)

  9. Outcome of cerebral arteriovenous malformations after linear accelerator reirradiation

    OpenAIRE

    Moraes, Paulo L.; Rodrigo S Dias; Eduardo Weltman; Adelmo J Giordani; Salomon Benabou; Segreto, Helena R. C.; Segreto, Roberto A.

    2015-01-01

    Background: The aim of this study was to evaluate the clinical outcome of patients undergoing single-dose reirradiation using the Linear Accelerator (LINAC) for brain arteriovenous malformations (AVM). Methods: A retrospective study of 37 patients with brain AVM undergoing LINAC reirradiation between April 2003 and November 2011 was carried out. Patient characteristics, for example, gender, age, use of medications, and comorbidities; disease characteristics, for example, Spetzler-Martin ...

  10. Evaluation of the environmental equivalent dose rate using area monitors for neutrons in clinical linear accelerators; Avaliacao da taxa de equivalente de dose ambiente utilizando monitores de area para neutrons em aceleradores lineares clinicos

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, Ana Paula; Pereira, Walsan Wagner; Patrao, Karla C. de Souza; Fonseca, Evaldo S. da, E-mail: asalgado@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Batista, Delano V.S. [Instituto Nacional do Cancer (INCa), Rio de Janeiro, RJ (Brazil)

    2009-07-01

    The Neutron Laboratory of the Radioprotection and Dosimetry Institute - IRD/CNEN, Rio de Janeiro, Brazil, initiated studies on the process of calibration of neutron area monitors and the results of the measurements performed at radiotherapy treatment rooms, containing clinical accelerators

  11. Linear accelerator calibration monitor with a memory

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, R.L.; Ekstrand, K.E.

    1979-09-01

    A calibration monitor has been designed for measuring the constancy of linear accelerator or cobalt unit output between full calibrations. This monitor is battery-operated, light-weight, and slides into the shadow tray attachment on a linear accelerator or cobalt unit for easy setup. It provides a digital readout of the dose delivered, and a consistency check can be made in less than two minutes. The precision of the monitor, determined by cobalt-60 irradiations over a 2 1/2 month period, is +- 0.6% (standard deviation). The monitor also retains the dose reading in a CMOS digital counter indefinitely, hence it can be used in the same fashion as mailed thermoluminescent dosimeters (TLD) for calibration checks at remote facilities without the complicated readout procedures associated with TLD. The monitor can be mailed to a remote facility, positioned without ambiguity, and irradiated; and the reading can be verified on return to the originating center simply by pressing a switch. The monitor can easily be set up to carry out a ''blind'' check in which the reading obtained is not known to the remote facility.

  12. Linear accelerator calibration monitor with a memory

    International Nuclear Information System (INIS)

    A calibration monitor has been designed for measuring the constancy of linear accelerator or cobalt unit output between full calibrations. This monitor is battery-operated, light-weight, and slides into the shadow tray attachment on a linear accelerator or cobalt unit for easy setup. It provides a digital readout of the dose delivered, and a consistency check can be made in less than two minutes. The precision of the monitor, determined by cobalt-60 irradiations over a 2 1/2 month period, is +- 0.6% (standard deviation). The monitor also retains the dose reading in a CMOS digital counter indefinitely, hence it can be used in the same fashion as mailed thermoluminescent dosimeters (TLD) for calibration checks at remote facilities without the complicated readout procedures associated with TLD. The monitor can be mailed to a remote facility, positioned without ambiguity, and irradiated; and the reading can be verified on return to the originating center simply by pressing a switch. The monitor can easily be set up to carry out a ''blind'' check in which the reading obtained is not known to the remote facility

  13. Application of linear induction accelerator for environmental applications

    International Nuclear Information System (INIS)

    Growing interest in the usage of power beams in industrial applications governs the design and development of various kinds of latest accelerators of high voltage, high energy, low current or high voltage high current but low average power accelerators. Conventional accelerators can be of electrostatic accelerators (Van-de-Graaff), high voltage multiplier column based accelerators (Cockcroft Walton/dynamatron type) or Microwave frequency based accelerators (R.F.LINAC) and Pulsed accelerators (Marx generator and PFL type). Linear Induction Accelerator (LIA) is linear in voltage acceleration configuration and beam gets coupled to the input pulse power by induction. It is compact and mobile compared to other accelerators of similar power regime. A unique feature of the induction accelerator is that peak voltage appears only at the output. This paper illustrates the principle and applications of linear Induction accelerator, global scenario and BARC status in this thrust area. (author)

  14. CULA: hybrid GPU accelerated linear algebra routines

    Science.gov (United States)

    Humphrey, John R.; Price, Daniel K.; Spagnoli, Kyle E.; Paolini, Aaron L.; Kelmelis, Eric J.

    2010-04-01

    The modern graphics processing unit (GPU) found in many standard personal computers is a highly parallel math processor capable of nearly 1 TFLOPS peak throughput at a cost similar to a high-end CPU and an excellent FLOPS/watt ratio. High-level linear algebra operations are computationally intense, often requiring O(N3) operations and would seem a natural fit for the processing power of the GPU. Our work is on CULA, a GPU accelerated implementation of linear algebra routines. We present results from factorizations such as LU decomposition, singular value decomposition and QR decomposition along with applications like system solution and least squares. The GPU execution model featured by NVIDIA GPUs based on CUDA demands very strong parallelism, requiring between hundreds and thousands of simultaneous operations to achieve high performance. Some constructs from linear algebra map extremely well to the GPU and others map poorly. CPUs, on the other hand, do well at smaller order parallelism and perform acceptably during low-parallelism code segments. Our work addresses this via hybrid a processing model, in which the CPU and GPU work simultaneously to produce results. In many cases, this is accomplished by allowing each platform to do the work it performs most naturally.

  15. Linear accelerator selection for the one-machine department

    International Nuclear Information System (INIS)

    Now that dual-photon linear accelerators with electron beams are readily available, many smaller radiation oncology departments are considering selection of one of these units to serve as their sole megavoltage treatment machine. This presentation reviews the issues to be considered in selecting a linear accelerator, including types and numbers of patients treated, staff experience, budget, facility considerations, physics support, and in-house and manufacturer service support. Data are presented from several departments in the Philadelphia area with single megavoltage treatment machines to illustrate the percentage of patients who could benefit from the availability of electron and higher energy photon beam treatments. The authors also present the 5-year experience of a large clinical department in utilization of low- and high-energy photon and electron treatments

  16. Introduction to electrodynamics for microwave linear accelerators

    International Nuclear Information System (INIS)

    This collection of notes and exercises is intended as a workbook to introduce the principles of microwave linear accelerators, starting with the underlying foundation in electrodynamics. The author reviewed Maxwell's equations, the Lorentz force law, and the behavior of fields near a conducting boundary. The author goes on to develop the principles of microwave electronics, including waveguide modes, circuit equivalence, shunt admittance of an iris, and voltage standing-wave ratio. The author constructed an elementary example of a waveguide coupled to a cavity, and examined its behavior during transient filling of the cavity, and in steady-state. He goes on to examine a periodic line. Then he examined the problem of acceleration in detail, studying first the properties of a single cavity-waveguide-beam system and developing the notions of wall Q, external Q, /Q shunt impedance, and transformer ratio. He then examined the behavior of such a system on and off resonance, on the bench, and under conditions of transient and steady-state beam-loading. This work provides the foundation for the commonly employed circuit equivalents and the basic scalings for such systems. Following this he examined the coupling of two cavities, powered by a single feed, and goes on to consider structures constructed from multiple coupled cavities. The basic scalings for constant impedance and constant gradient traveling-wave structures are set down, including features of steady-state beam-loading, and the coupled-circuit model. Effects of uniform and random detuning are derived. These notes conclude with a brief outline of some problems of current interest in accelerator research

  17. Introduction to electrodynamics for microwave linear accelerators

    International Nuclear Information System (INIS)

    This collection of notes and exercises is intended as a workbook to introduce the principles of microwave linear accelerators, starting with the underlying foundation in electrodynamics. We review Maxwell's equations, the Lorentz force law, and the behavior of fields near a conducting boundary. We go on to develop the principles of microwave electronics, including waveguide modes, circuit equivalence, shunt admittance of an iris, and voltage standing-wave ratio. We construct an elementary example of a waveguide coupled to a cavity, and examine its behavior during transient filling of the cavity, and in steady-state. We go on to examine a periodic line. We then turn to examine the problem of acceleration in detail, studying first the properties of a single cavity-waveguide-beam system and developing the notions of wall Q, external Q, [R/Q], shunt impedance, and transformer ratio. We examine the behavior of such a system on and off resonance, on the bench, and under conditions of transient and steady-state beam-loading. This work provides the foundation for the commonly employed circuit equivalents and the basic scalings for such systems. Following this we examine the coupling of two cavities, powered by a single feed, and go on to consider structures constructed from multiple coupled cavities. The basic scalings for constant impedance and constant gradient travelling-wave structures are derived, including features of steady-state beam-loading, and the coupled-circuit model. Effects of uniform and random detuning are derived. These notes conclude with a brief outline of some problems of current interest in accelerator research. (author)

  18. Three-dimensional conformal arc radiotherapy using a C-arm linear accelerator with a computed tomography on-rail system for prostate cancer: clinical outcomes

    International Nuclear Information System (INIS)

    We report the feasibility and treatment outcomes of image-guided three-dimensional conformal arc radiotherapy (3D-CART) using a C-arm linear accelerator with a computed tomography (CT) on-rail system for localized prostate cancer. Between 2006 and 2011, 282 consecutive patients with localized prostate cancer were treated with in-room CT-guided 3D-CART. Biochemical failure was defined as a rise of at least 2.0 ng/ml beyond the nadir prostate-specific antigen level. Toxicity was scored according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0. A total of 261 patients were analyzed retrospectively (median follow-up: 61.6 months). The median prescribed 3D-CART dose was 82 Gy (2 Gy/fraction, dose range: 78–86 Gy), and 193 of the patients additionally received hormonal therapy. The 5-year overall survival rate was 93.9 %. Among low-, intermediate-, and high-risk patients, 5-year rates of freedom from biochemical failure were 100, 91.5 and 90.3 %, respectively. Rates of grade 2–3 late gastrointestinal and genitourinary toxicities were 2.3 and 11.4 %, respectively. No patient experienced late grade 4 or higher toxicity. In-room CT-guided 3D-CART was feasible and effective for localized prostate cancer. Treatment outcomes were comparable to those previously reported for intensity-modulated radiotherapy

  19. Activation products in medical linear accelerators

    International Nuclear Information System (INIS)

    Full text of publication follows: Medical linear accelerators (linacs) are today the megavoltage treatment unit of choice in many modern radiotherapy departments. As is well known, the interaction of high energy gamma photons and the accompanying neutrons from linacs operating at energies above 10 MeV will activate the accelerator itself, treatment aids, the surrounding air and the structure of the treatment room producing radioactive species. To determine the radiation burden to the staff due to induced activity, measurements were performed immediately after treatment and 48 hours later at four different brands of treatment machines under the same experimental conditions. These brands and their maximum operating photon energies are Elekta (15 MV), Siemens (15 MV), Varian (15 MV) and General Electric (18 MV). A portable high purity germanium detector system (Canberra) and a dose rate meter (Berthold) were used to collect gamma spectra and measure the induced dose rate respectively at the iso-centre. The Genie PC Spectroscopy Software Package from Canberra Industries was utilized to analyze the spectra. Radioactive species identified include 24Na, 28Al, 51Cr, 54Mn, 56Mn, 57Co, 58Co, 59Fe, 60Co, 64Cu, 65Zn, 82Br, 99Mo, 122Sb, 124Sb, 184Re, 187W, 196Au, and 203Pb and their respective apparent activity values were calculated. With the help of the gamma dose rate constant, the induced dose rates for all identified isotopes were computed. The measured dose rates ranged between 1.4 and 2.7 μSv/h 2 mins after beam-off and between 0.5 and 1.57 μSv/h 10 mins after beam-off. Forty-eight hours after beam off the dose rate ranged between 0.11 and 0.28 μSv/h. Detailed results and conclusions for radiation protection of staff and service personnel will be presented. (authors)

  20. Luminosity Limitations in Linear Colliders Based on Plasma Acceleration

    CERN Document Server

    Lebedev, Valeri; Nagaitsev, Sergei

    2016-01-01

    Particle acceleration in plasma creates a possibility of exceptionally high accelerating gradients and appears as a very attractive option for future linear electron-positron and/or photon-photon colliders. These high accelerating gradients were already demonstrated in a number of experiments. However, a linear collider requires exceptionally high beam brightness which still needs to be demonstrated. In this article we discuss major phenomena which limit the beam brightness of accelerated beam and, consequently, the collider luminosity.

  1. Multi-beam linear accelerator EVT

    Science.gov (United States)

    Teryaev, Vladimir E.; Kazakov, Sergey Yu.; Hirshfield, Jay L.

    2016-09-01

    A novel electron multi-beam accelerator is presented. The accelerator, short-named EVT (Electron Voltage Transformer) belongs to the class of two-beam accelerators. It combines an RF generator and essentially an accelerator within the same vacuum envelope. Drive beam-lets and an accelerated beam are modulated in RF modulators and then bunches pass into an accelerating structure, comprising uncoupled with each other and inductive tuned cavities, where the energy transfer from the drive beams to the accelerated beam occurs. A phasing of bunches is solved by choice correspond distances between gaps of the adjacent cavities. Preliminary results of numerical simulations and the initial specification of EVT operating in S-band, with a 60 kV gun and generating a 2.7 A, 1.1 MV beam at its output is presented. A relatively high efficiency of 67% and high design average power suggest that EVT can find its use in industrial applications.

  2. Smooth ion energy tuning in linear accelerator

    International Nuclear Information System (INIS)

    This paper presents the results of experimental research of energy variable proton linac, which consists of independently driven one-gap accelerating cavities. Cavity design proposed by authors seems to be optimal for high values of energy gain and beam current. A multichannel accelerating structure allows to accelerate several ion beams. Beam focusing is accomplished by means of electrostatic quadruples with variable potential, which is chosen from the viewpoint of maximum beam transit factor for each operation mode, determined by output energy. The other energy variable accelerating structures with operating frequency changing are also under consideration. (author)

  3. Accelerator physics of the Stanford Linear Collider and SLC accelerator experiments towards the Next Linear Collider

    Energy Technology Data Exchange (ETDEWEB)

    Seeman, J.T.

    1992-06-01

    The Stanford Linear Collider (SLC) was built to collide single bunches of electrons and positrons head-on at a single interaction point with single beam energies up to 55 GeV. The small beam sizes and high currents required for high luminosity operation have significantly pushed traditional beam quality limits. The Polarized Electron Source produces about 8 {times} 10{sup 10} electrons in each of two bunches with up to 28% polarization,. The Damping Rings provide coupled invariant emittances of 1.8 {times} 10{sup {minus}5} r-m with 4.5 {times} 10{sup 10} particles per bunch. The 57 GeV Linac has successfully accelerated over 3 {times} 10{sup 10} particles with design invariant emittances of 3 {times} 10{sup {minus}5} r-m. Both longitudinal and transverse wakefields affect strongly the trajectory and emittance corrections used for operations. The Arc systems routinely transport decoupled and betatron matched beams. In the Final Focus, the beams are chromatically corrected and demagnified producing spot sizes of 2 to 3 {mu}m at the focal point. Spot sizes below 2 {mu}m have been made during special tests. Instrumentation and feedback systems are well advanced, providing continuous beam monitoring and pulse-by-pulse control. A luminosity of 1.6 {times} 10{sup 29} cm{sup {minus}2}sec{sup {minus}1} has been produced. Several experimental tests for a Next Linear Collider (NLC) are being planned or constructed using the SLC accelerator as a test facility. The Final Focus Test Beam will demagnify a flat 50 GeV electron beam to dimensions near 60 nm vertically and 900 nm horizontally. A potential Emittance Dynamics Test Area has the capability to test the acceleration and transport of very low emittance beams, the compression of bunch lengths to 50 {mu}m, the acceleration and control of multiple bunches, and the properties of wakefields in the very short bunch length regime.

  4. Cavity characterization for general use in linear electron accelerators

    International Nuclear Information System (INIS)

    The main objective of this work is to is to develop measurement techniques for the characterization of microwave cavities used in linear electron accelerators. Methods are developed for the measurement of parameters that are essential to the design of an accelerator structure using conventional techniques of resonant cavities at low power. Disk-loaded cavities were designed and built, similar to those in most existing linear electron accelerators. As a result, the methods developed and the estimated accuracy were compared with those from other investigators. The results of this work are relevant for the design of cavities with the objective of developing linear electron accelerators. (author)

  5. Compact accelerator for clinical use

    International Nuclear Information System (INIS)

    The first clinical trial with carbon beams generated from the HIMAC was conducted in June 1994. The total number of patients treated as of October 2006 is in excess of 3,000. In view of the significant growth in the number of protocols, the Japanese government gave its approval for carbon-ion therapy at NIRS as an advanced medical technology in 2003. The impressive advances of carbon-ion therapy using HIMAC have been supported by high-reliability operation and by advanced developments of beam-delivery and accelerator technologies. Based on our ten years of experience with HIMAC, we recently proposed a compact carbon-ion therapy facility for widespread use in Japan. The key technologies of the accelerator and irradiation systems for this compact facility have been under development since April 2004, with the main thrust being focused on downsizing the facility for cost reduction. On the basis of the design and R and D studies for the compact carbon-ion facility, its construction was begun at Gunma University in April 2006. In addition, our future plans for HIMAC also include the design of a new treatment facility. The design work has already been initiated and will lead to the further development of therapy using HIMAC. The following descriptions give a summary account of the carbon-ion treatment facility and of the HIMAC facility. (author)

  6. Induction linear accelerator technology for SDIO applications

    International Nuclear Information System (INIS)

    The research effort reported concentrated primarily on three major activities. The first was aimed at improvements in the accelerator drive system of an induction linac to meet the high repetition rate requirements of SDI applications. The second activity centered on a redesign of the accelerator cells to eliminate the beam breakup instabilities, resulting in optimized beam transport. The third activity sought to improve the source of electrons to achieve a higher quality beam to satisfy the requirement of the free electron laser

  7. Development of new elements of automated control systems linear accelerator

    International Nuclear Information System (INIS)

    For monitoring systems and control of linear electron accelerators have been designed, manufactured and introduced new elements instead of physically and morally outdated. This family of analog-to-digital converters ADC 01, ADC-02 ADC-03, ADC-05 ADC-06 have been developed in cooperation with the KNURE, and synchronizer for linear accelerator LUE-60M, designed forces of employees the research complex ''ACCELERATOR'' KIPT. Purpose, characteristics, technical description, block diagrams of family of analog-to-digital converters ADC01...ADC06 and of synchronizer of linear accelerator LUE-60M is presented in a report. These devices are developed on a new element base and inculcated in automated control systems of linear accelerators.

  8. Self-shielded electron linear accelerators designed for radiation technologies

    Science.gov (United States)

    Belugin, V. M.; Rozanov, N. E.; Pirozhenko, V. M.

    2009-09-01

    This paper describes self-shielded high-intensity electron linear accelerators designed for radiation technologies. The specific property of the accelerators is that they do not apply an external magnetic field; acceleration and focusing of electron beams are performed by radio-frequency fields in the accelerating structures. The main characteristics of the accelerators are high current and beam power, but also reliable operation and a long service life. To obtain these characteristics, a number of problems have been solved, including a particular optimization of the accelerator components and the application of a variety of specific means. The paper describes features of the electron beam dynamics, accelerating structure, and radio-frequency power supply. Several compact self-shielded accelerators for radiation sterilization and x-ray cargo inspection have been created. The introduced methods made it possible to obtain a high intensity of the electron beam and good performance of the accelerators.

  9. Neutron transport in a clinical linear accelerator bunker: comparison of materials for reducing the photo-neutron dose at the maze entrance

    International Nuclear Information System (INIS)

    Megavoltage photons above 10 MeV used in external beam radiotherapy lead to a significant photo-neutron fluence, which must be taken into account in bunker design (IPEM, 1997, Report 75, The design of radiotherapy treatment room facilities). This work describes Monte-Carlo simulations of such neutrons for a proposed bunker, which is to house a 15 MV accelerator. Neutron fluence spectra and absorbed dose due to neutrons and neutron-capture photons were scored at the accelerator iso centre and at the maze entrance for mono-energetic neutron sources of 0.5, 3 and 6 MeV. The reduction in neutron and photon dose at the maze entrance, achieved by cladding concrete maze walls with either wood, polyethylene or a commercially available plastic, was determined.

  10. Superpower linear proton accelerator for neutron generator and accelerator-driven system

    International Nuclear Information System (INIS)

    The perspectives of development of superpower linear proton accelerators for high-intensive neutron generators and accelerator-driven systems are discussed. The main technical characteristics of the projects on neutron generators based on linear accelerators are presented. These projects are developed in USA, Japan, Italy and Russia. The RFQ structures are used in all projects for the initial acceleration of protons up to 5-7 MeV. The different modifications of drift tubes are applied for acceleration up to 100 MeV. The main acceleration (up to 1 GeV) is supposed to perform in superconducting resonators

  11. Test Stand for Linear Induction Accelerator Optimization

    International Nuclear Information System (INIS)

    Lawrence Livermore National Laboratory has designed and constructed a test stand to improve the voltage regulation in our Flash X-Ray (FXR) accelerator cell. The goal is to create a more mono-energetic electron beam that will create an x-ray source with a smaller spot size. Studying the interaction of the beam and pulse-power system with the accelerator cell will improve the design of high-current accelerators at Livermore and elsewhere. On the test stand, a standard FXR cell is driven by a flexible pulse-power system and the beam current is simulated with a switched center conductor. The test stand is fully instrumented with high-speed digitizers to document the effect of impedance mismatches when the cell is operated under various full-voltage conditions. A time-domain reflectometry technique was also developed to characterize the beam and cell interactions by measuring the impedance of the accelerator and pulse-power component. Computer models are being developed in parallel with the testing program to validate the measurements and evaluate different design changes. Both 3D transient electromagnetic and circuit models are being used

  12. Discussion of high brightness rf linear accelerators

    International Nuclear Information System (INIS)

    The fundamental aspects of high-brightness rf linacs are outlined, showing the breadth and complexity of the technology and indicating that synergism with advancements in other areas is important. Areas of technology reviewed include ion sources, injectors, rf accelerator structures, beam dynamics, rf power, and automatic control

  13. A brief history of high power RF proton linear accelerators

    International Nuclear Information System (INIS)

    The first mention of linear acceleration was in a paper by G. Ising in 1924 in which he postulated the acceleration of positive ions induced by spark discharges which produced electric fields in gaps between a series of open-quotes drift tubesclose quotes. Ising apparently was not able to demonstrate his concept, most likely due to the limited state of electronic devices. Ising's work was followed by a seminal paper by R. Wideroe in 1928 in which he demonstrated the first linear accelerator. Wideroe was able to accelerate sodium or potassium ions to 50 keV of energy using drift tubes connected alternately to high frequency waves and to ground. Nuclear physics during this period was interested in accelerating protons, deuterons, electrons and alpha particles and not heavy ions like sodium or potassium. To accelerate the light ions required much higher frequencies than available at that time. So linear accelerators were not pursued heavily at that time. Research continued during the 1930s but the development of high frequency RF tubes for radar applications in World War 2 opened the potential for RF linear accelerators after the war. The Berkeley laboratory of E. 0. Lawrence under the leadership of Luis Alvarez developed a new linear proton accelerator concept that utilized drift tubes that required a full RF period to pass through as compared to the earlier concepts. This development resulted in the historic Berkeley 32 MeV proton linear accelerator which incorporated the open-quotes Alvarez drift tubeclose quotes as the basic acceleration scheme using surplus 200 MHz radar components

  14. Multistage linear electron acceleration using pulsed transmission lines

    International Nuclear Information System (INIS)

    A four-stage linear electron accelerator is described which uses pulsed radial transmission lines as the basic accelerating units. An annular electron beam produced by a foilless diode is guided through the accelerator by a strong axial magnetic field. Synchronous firing of the injector and the acccelerating modules is accomplished with self-breaking oil switches. The device has accelerated beam currents of 25 kA to kinetic energies of 9 MV, with 90% current transport efficiency. The average accelerating gradient is 3 MV/m

  15. Wakefields and Instabilities in Linear Accelerators

    CERN Document Server

    Ferrario, M; Palumbo, L

    2014-01-01

    When a charged particle travels across the vacuum chamber of an accelerator, it induces electromagnetic fields, which are left mainly behind the generating particle. These electromagnetic fields act back on the beam and influence its motion. Such an interaction of the beam with its surro undings results in beam energy losses, alters the shape of the bunches, and shifts the betatron and synchrotron frequencies. At high beam current the fields can even lead to instabilities, thus limiting the performance of the accelerator in terms of beam quality and current intensity. We discuss in this lecture the general features of the electromagnetic fields, introducing the concepts of wakefields and giving a few simple examples in cylindrical geometry. We then show the effect of the wakefields on the dynamics of a beam in a linac, dealing in particular with the beam breakup instability and how to cure it.

  16. Neutron transport in a clinical linear accelerator bunker: comparison of materials for reducing the photo-neutron dose at the maze entrance

    International Nuclear Information System (INIS)

    Megavoltage photons above 10 MeV used in external beam radiotherapy lead to a significant photoneutron fluence, which must be taken into account in bunker design. This work describes Monte-Carlo simulations of such neutrons for a proposed bunker which is to house a 15 MV accelerator. Of particular interest was the effect on the neutron dose at the maze entrance, of cladding maze walls with various materials. Simulations were performed using the MCNP4B Monte-Carlo code. Mean photo-neutron energies of 0.5, 3 and 6 MeV were assumed to be produced isotropically from the accelerator head. Neutron fluence spectra and absorbed dose due to neutrons and neutron-capture photons were scored at the machine isocentre and at the maze entrance in a 30 cm diameter sphere of tissue. Absorbed dose at the maze entrance was then determined relative to isocentre dose. The reduction in neutron dose at the maze entrance, achieved by cladding concrete maze walls with either wood, polystyrene or a commercially available plastic, was determined. A comparison of materials has been made in terms of efficiency and cost implications. (author)

  17. Observation and analysis of oscillations in linear accelerators

    International Nuclear Information System (INIS)

    This report discusses the following on oscillation in linear accelerators: Betatron Oscillations; Betatron Oscillations at High Currents; Transverse Profile Oscillations; Transverse Profile Oscillations at High Currents.; Oscillation and Profile Transient Jitter; and Feedback on Transverse Oscillations

  18. Space charge in linear accelerators workshop. [Eighteen papers

    Energy Technology Data Exchange (ETDEWEB)

    Jameson, R.A. (ed.)

    1978-05-01

    Nineteen papers and three summary sessions (theoretical, simulation codes, and experimental approach) are presented on the effects of space charge in linear accelerators. A separate abstract was prepared for each paper for inclusion in Energy Research Abstracts (ERA). (PMA)

  19. Observation of high current effects in high energy linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Seeman, J.T.

    1991-12-01

    The acceleration and transport of electron beams with high currents and low emittances are subjects studied very carefully for many operating accelerators and most future accelerators. For a example, several Free Electron Lasers (FEL) and the Stanford Linear Collider (SLC) presently operate with high energy intense beams. The next generation of synchrotron light sources and future linear colliders require a much higher degree of component precision and beam control. In this note the basic concepts governing the effects of high currents in accelerators are explored, including observations of high currents in present accelerators. The effects of longitudinal wakefields on acceleration and energy spreads are studied first. Then, the transverse equations of motion are developed including the technique of BNS damping to control wakefield growth. These wakefield effects are investigated to characterize their influence on the control and observation of beam oscillations. Finally, the reduction of transverse wakefield effects is important for maintaining the emittance of intense beams. 49 refs., 48 figs.

  20. Observation of high current effects in high energy linear accelerators

    International Nuclear Information System (INIS)

    The acceleration and transport of electron beams with high currents and low emittances are subjects studied very carefully for many operating accelerators and most future accelerators. For a example, several Free Electron Lasers (FEL) and the Stanford Linear Collider (SLC) presently operate with high energy intense beams. The next generation of synchrotron light sources and future linear colliders require a much higher degree of component precision and beam control. In this note the basic concepts governing the effects of high currents in accelerators are explored, including observations of high currents in present accelerators. The effects of longitudinal wakefields on acceleration and energy spreads are studied first. Then, the transverse equations of motion are developed including the technique of BNS damping to control wakefield growth. These wakefield effects are investigated to characterize their influence on the control and observation of beam oscillations. Finally, the reduction of transverse wakefield effects is important for maintaining the emittance of intense beams. 49 refs., 48 figs

  1. Proceeding of the 11th meeting on linear accelerators

    International Nuclear Information System (INIS)

    The study group on linear accelerators has attained the period of 10 years. The worldwide change of social structure and economical condition during this period affected also linear accelerators. For a while, the new installation of linear accelerators was limited to Japan and China, and the state of standstill continued in Europe and America. Therefore, the large scale projects of electron-positron collision type accelerators started, and LEP of CERN and HERA of DESY in Europe and Linear Collider of SLAC in USA compete the lead together with TRISTAN in Japan. Large electron rings have become the type connecting CW linear accelerators with electromagnets in circular form unlike the conventional type. The developed type of superconducting CW linacs such as CEBAF in USA is planned. In the large accelerators hereafter of CW or pulse type, the RF system of high accuracy and large power output is the key to the success of projects, instead of individual accelerating spaces, high frequency sources, waveguides or controls. When the scale of projects exceeds a certain limit, those cannot be dealt with merely by the experience and means in the past. In this book, the gists of 62 presented papers and invited lectures are collected. (Kako, I.)

  2. Electron gun for technological linear accelerator

    International Nuclear Information System (INIS)

    The work is purposed to the design of diode electron gun for powerful technologic electron linac and to experimental investigations of the beam parameters at the gun exit.The gun feature is the quick cathode replacement.This is very impotent for operating of the accelerator.The gun optics and beam parameters were calculated using the EGUN code.Beam parameters were investigated as at the special test stand so as component of the linac injector.The gun produces the beam current of 2 A at the anode voltage 25 kV.Measured beam parameters correspond to calculated results

  3. Application of local area networks to accelerator control systems at the Stanford Linear Accelerator

    International Nuclear Information System (INIS)

    The history and current status of SLAC's SDLC networks for distributed accelerator control systems are discussed. These local area networks have been used for instrumentation and control of the linear accelerator. Network topologies, protocols, physical links, and logical interconnections are discussed for specific applications in distributed data acquisition and control system, computer networks and accelerator operations

  4. Application of local area networks to accelerator control systems at the Stanford Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Fox, J.D.; Linstadt, E.; Melen, R.

    1983-03-01

    The history and current status of SLAC's SDLC networks for distributed accelerator control systems are discussed. These local area networks have been used for instrumentation and control of the linear accelerator. Network topologies, protocols, physical links, and logical interconnections are discussed for specific applications in distributed data acquisition and control system, computer networks and accelerator operations.

  5. The role of linear accelerators in industry

    International Nuclear Information System (INIS)

    The short-term demand of ionizing energy will increase rapidly due to developing irradiation markets in sludge irradiation, medical product sterilization, biological toxic waste sterilization, exhaust gas treatment, and the much larger area of food disinfestation. Incentives for the increase are due not only to inherent positive characteristics of ionizing radiation, but to the worldwide concern and increased awareness of currently used fumigants, such as methyl bromide, ethylene dibromide, and ethylene oxide. Cobalt-60 is a gamma-emitting isotope, produced primarily by the Atomic Energy of Canada Limited, which can help to satisfy these developing market demands. As an alternative to cobalt-60, the US Department of Energy is promoting cesium-137, a gamma emitter obtained from reprocessed nuclear waste. However, the supply of these two isotopes is limited and unable to meet the projected ionizing energy demands. Utilization of accelerator technology is therefore critical to the development of various product irradiation programs. It will not only meet the demand which is in excess of that covered by the isotopes, but it will also release the limited quantities of isotope for better use in roles for which they are especially suited. The accelerator and isotope roles in the irradiation markets need to be more finely focused in the future to benefit the growth of both systems. (orig.)

  6. The Next Linear Collider test accelerator: Status and results

    International Nuclear Information System (INIS)

    At SLAC, the authors are pursuing the design of a Next Linear Collider (NLC) which would begin with a center-of-mass energy of 0.5 TeV, and would be upgradable to 1.0 TeV and beyond. To achieve this high energy, for the past several years they have been working on the development of a high-gradient 11.4-GHz (X-band) linear accelerator for the main linac of the collider. In this paper, they present the status and initial results from the ''Next Linear Collider Test Accelerator'' (NLCTA). The goal of the NLCTA is to model the high gradient linac of the NLC. It incorporates the new technologies of X-band accelerator structures, rf pulse compression systems and high-power klystrons into a 0.5 to 1.0 GeV linac which is a test bed for beam dynamics issues related to high-gradient acceleration

  7. Development of four-beam IH-RFQ linear accelerator

    International Nuclear Information System (INIS)

    A multi-beam linear accelerator (linac) that accelerates the multiple beams in an acceleration cavity has advantages for downsizing and cost reduction of the linac system. However, the configuration of electrodes of the multi-beam linac is more complicated than that of single beam type, and so it influences the resonance frequency. A minimum of cavity diameter is restricted by the volume of electrodes, which depends largely on the numbers of beams. The relation between the numbers of beam and the acceleration structure is studied with electromagnetic simulation. (author)

  8. Proton linear accelerators: A theoretical and historical introduction

    International Nuclear Information System (INIS)

    From the beginning, the development of linear accelerators has followed a number of different directions. This report surveys the basic ideas and general principles of such machines, pointing out the problems that have led to the various improvements, with the hope that it may also aid further progress. After a brief historical survey, the principal aspects of accelerator theory are covered in some detail: phase stability, focusing, radio-frequency accelerating structures, the detailed calculation of particle dynamics, and space-charge effects at high intensities. These developments apply essentially to proton and ion accelerators, and only the last chapter deals with a few aspects relative to electrons. 134 refs

  9. Proton linear accelerators: A theoretical and historical introduction

    Energy Technology Data Exchange (ETDEWEB)

    Lapostolle, P.M.

    1989-07-01

    From the beginning, the development of linear accelerators has followed a number of different directions. This report surveys the basic ideas and general principles of such machines, pointing out the problems that have led to the various improvements, with the hope that it may also aid further progress. After a brief historical survey, the principal aspects of accelerator theory are covered in some detail: phase stability, focusing, radio-frequency accelerating structures, the detailed calculation of particle dynamics, and space-charge effects at high intensities. These developments apply essentially to proton and ion accelerators, and only the last chapter deals with a few aspects relative to electrons. 134 refs.

  10. Characteristics of induced activity from medical linear accelerators

    International Nuclear Information System (INIS)

    A study of the induced activity in a medical linear accelerator (linac) room was carried out on several linac installations. Higher beam energy, higher dose rate, and larger field size generally result in higher activation levels at a given point of interest, while the use of multileaf collimators (MLC) can also increase the activation level at the isocenter. Both theoretical and experimental studies reveal that the activation level in the morning before any clinical work increases from Monday to Saturday and then decreases during the weekend. This weekly activation picture keeps stable from one week to another during standard clinical operation of the linac. An effective half-life for a given point in the treatment room can be determined from the measured or calculated activity decay curves. The effective half-life for points inside the treatment field is longer than that for points outside of the field in the patient plane, while a larger field and longer irradiation time can also make the effective half-life longer. The activation level reaches its practical saturation value after a 30 min continuous irradiation, corresponding to 12 000 MU at a 'dose rate' of 400 MU/min. A 'dose' of 300 MU was given 20 times in 15 min intervals to determine the trends in the activation level in a typical clinical mode. As well, a long-term (85 h over a long weekend) decay curve was measured to evaluate the long-term decay of room activation after a typical day of clinical linac use. A mathematical model for the activation level at the isocenter has been established and shown to be useful in explaining and predicting the induced activity levels for typical clinical and experimental conditions. The activation level for a 22 MeV electron beam was also measured and the result shows it is essentially negligible

  11. Radiosurgery with a linear accelerator in cerebral arteriovenous malformations

    Energy Technology Data Exchange (ETDEWEB)

    Esteves, Sergio Carlos Barros; Nadalin, Wladimir; Piske, Ronie Leo; Benabou, Salomon; Souza, Evandro de; Oliveira, Antonio Carlos Zuliani de [Hospital Beneficencia Portuguesa de Sao Paulo, Sao Paulo, SP (Brazil)]. E-mail: estevesrt@uol.com.br

    2008-07-01

    Objective. To evaluate results achieved with radiosurgery and complications of the procedure when treating arteriovenous malformations with linear accelerator. Methods. This retrospective study was conducted between October 1993 and December 1996. Sixty-one patients with arteriovenous malformations were treated with radiosurgery utilizing a 6 MW energy linear accelerator. Ages of the 32 female and 29 male patients ranged from 6 to 54 years (mean: 28.3 years). The most frequent initial symptom was cephalea (45.9%), followed by neurological deficit (36.1%). Cerebral hemorrhage diagnosed by image was observed in 35 patients (57.3%). Most arteriovenous malformations (67.2%) were graded Spetzler III and IV. Venous stenosis (21.3%) and aneurysm (13.1%) were the most frequent angio-architecture changes. The dose administered varied from 12 to 27.5 Gy in the periphery of the lesion. Results. Out of twenty-eight patients that underwent conclusive angiography control, complete obliteration was achieved in 18 (72%) and treatment failed in 7 (absence of occlusion with more than 3 years of follow-up). Four were submitted to a second radiosurgery, and one of these has shown obliteration after 18 months of follow-up. Discussion. Several factors were analyzed regarding the occlusion rate (gender, age, volume, localization, Spetzler, flow , embolization, total of isocenters, prescribed dose and chosen isodose) and complications (total of isocenters, localization, volume, maximum dose, prescribed dose and chosen isodose). Analyzed variables showed no statistical significance for obliteration of the vessel, as well as for treatment complications. The largest diameter of the arteriovenous malformation, its volume and the dose administered did not influence time of obliteration. Conclusion. Radiosurgery is effective in the treatment of arteriovenous malformations and can be an alternative for patients with clinical contraindication or with lesions in eloquent areas. In the studied

  12. X-band coaxial standing-wave linear accelerator structure

    International Nuclear Information System (INIS)

    A new high efficiency X-Band, standing-wave linear accelerator cavity structure has been developed. It utilizes a shaped coaxial cavity as the coupling cavity between accelerating cavities for π/2 mode operation, hence the overall diameter is extremely small while maintaining a very high shunt impedance. The coupling cavity and accelerating cavity are easily machined on opposite sides of a single cell, eliminating any subassembly steps. Cavity geometries were developed using the computer codes LACC and LALA. Prototype 1.5 MeV and 4.0 MeV, 20 cm long accelerators are now under development. The accelerators employ a stepped field focusing technique to keep the beam focused at low field levels. The beam dynamics code PARMELA was used to optimize the longitudinal bunching and transverse beam characteristics. The accelerator design parameters, as well as experimental results, are presented

  13. Physical-dosimetric enabling a dual linear accelerator 3D planning systems for radiotherapy

    International Nuclear Information System (INIS)

    The process of commissioning clinical linear accelerator requires a dual comprehensive study of the therapeutic beam parameters, both photons Electron. All information gained by measuring physical and dosimetric these beams must be analyzed, processed and refined for further modeling in computer-based treatment planning (RTPS). Of professionalism of this process will depend on the accuracy and precision of the calculations the prescribed doses. This paper aims to demonstrate availability clinical linear accelerator system-RTPS with late radiotherapy treatments shaped beam of photons and electrons. (author)

  14. Conjugate Gradient Acceleration of Non-Linear Smoothing Filters

    OpenAIRE

    Knyazev, Andrew; Malyshev, Alexander,

    2015-01-01

    The most efficient signal edge-preserving smoothing filters, e.g., for denoising, are non-linear. Thus, their acceleration is challenging and is often performed in practice by tuning filter parameters, such as by increasing the width of the local smoothing neighborhood, resulting in more aggressive smoothing of a single sweep at the cost of increased edge blurring. We propose an alternative technology, accelerating the original filters without tuning, by running them through a special conjuga...

  15. Study of electron groupings in the Saclay linear accelerator

    International Nuclear Information System (INIS)

    The classical theory of the linear accelerator buncher does not fit the experimental measurements of the shape of the bunch of electrons performed at Saclay by the method of the energy spectrum. If the spurious effect of the mode converter at the input of the linac is taken into account the theory can fit the experimental results and also explain the variations of the phase of the bunch on the accelerating sine wave. (authors)

  16. Linear induction accelerators for fusion and neutron production

    International Nuclear Information System (INIS)

    Linear induction accelerators (LIA) with pulsed power drives can produce high energy, intense beams or electrons, protons, or heavy ions with megawatts of average power. The continuing development of highly reliable LIA components permits the use such accelerators as cost-effective beam sources to drive fusion pellets with heavy ions, to produce intense neutron fluxes using proton beams, and to generate with electrons microwave power to drive magnetic fusion reactors and high gradient, rf-linacs

  17. Non-linear diffusive shock acceleration with free escape boundary

    OpenAIRE

    Caprioli, D.; Amato, E.; P. Blasi(INAF Arcetri)

    2009-01-01

    We present here a semi-analytical solution of the problem of particle acceleration at non-linear shock waves with a free escape boundary at some location upstream. This solution, besides allowing us to determine the spectrum of particles accelerated at the shock front, including the shape of the cutoff at some maximum momentum, also allows us to determine the spectrum of particles escaping the system from upstream. This latter aspect of the problem is crucial for establishing a connection bet...

  18. MO-F-16A-02: Simulation of a Medical Linear Accelerator for Teaching Purposes

    International Nuclear Information System (INIS)

    Purpose: Detailed functioning of linear accelerator physics is well known. Less well developed is the basic understanding of how the adjustment of the linear accelerator's electrical components affects the resulting radiation beam. Other than the text by Karzmark, there is very little literature devoted to the practical understanding of linear accelerator functionality targeted at the radiotherapy clinic level. The purpose of this work is to describe a simulation environment for medical linear accelerators with the purpose of teaching linear accelerator physics. Methods: Varian type lineacs were simulated. Klystron saturation and peak output were modelled analytically. The energy gain of an electron beam was modelled using load line expressions. The bending magnet was assumed to be a perfect solenoid whose pass through energy varied linearly with solenoid current. The dose rate calculated at depth in water was assumed to be a simple function of the target's beam current. The flattening filter was modelled as an attenuator with conical shape, and the time-averaged dose rate at a depth in water was determined by calculating kerma. Results: Fifteen analytical models were combined into a single model called SIMAC. Performance was verified systematically by adjusting typical linac control parameters. Increasing klystron pulse voltage increased dose rate to a peak, which then decreased as the beam energy was further increased due to the fixed pass through energy of the bending magnet. Increasing accelerator beam current leads to a higher dose per pulse. However, the energy of the electron beam decreases due to beam loading and so the dose rate eventually maximizes and the decreases as beam current was further increased. Conclusion: SIMAC can realistically simulate the functionality of a linear accelerator. It is expected to have value as a teaching tool for both medical physicists and linear accelerator service personnel

  19. MO-F-16A-02: Simulation of a Medical Linear Accelerator for Teaching Purposes

    Energy Technology Data Exchange (ETDEWEB)

    Carlone, M [Princess Margaret Hospital, Toronto, ON (Canada); Lamey, M; Anderson, R; MacPherson, M [Credit Valley Hospital and Trillium Health Center, Mississauga, ON (Canada)

    2014-06-15

    Purpose: Detailed functioning of linear accelerator physics is well known. Less well developed is the basic understanding of how the adjustment of the linear accelerator's electrical components affects the resulting radiation beam. Other than the text by Karzmark, there is very little literature devoted to the practical understanding of linear accelerator functionality targeted at the radiotherapy clinic level. The purpose of this work is to describe a simulation environment for medical linear accelerators with the purpose of teaching linear accelerator physics. Methods: Varian type lineacs were simulated. Klystron saturation and peak output were modelled analytically. The energy gain of an electron beam was modelled using load line expressions. The bending magnet was assumed to be a perfect solenoid whose pass through energy varied linearly with solenoid current. The dose rate calculated at depth in water was assumed to be a simple function of the target's beam current. The flattening filter was modelled as an attenuator with conical shape, and the time-averaged dose rate at a depth in water was determined by calculating kerma. Results: Fifteen analytical models were combined into a single model called SIMAC. Performance was verified systematically by adjusting typical linac control parameters. Increasing klystron pulse voltage increased dose rate to a peak, which then decreased as the beam energy was further increased due to the fixed pass through energy of the bending magnet. Increasing accelerator beam current leads to a higher dose per pulse. However, the energy of the electron beam decreases due to beam loading and so the dose rate eventually maximizes and the decreases as beam current was further increased. Conclusion: SIMAC can realistically simulate the functionality of a linear accelerator. It is expected to have value as a teaching tool for both medical physicists and linear accelerator service personnel.

  20. Determination of beam characteristic parameters for a linear accelerator

    International Nuclear Information System (INIS)

    A mechanism to determine electron beam characteristic parameters of a linear accelerator was constructed. The mechanism consists in an electro-calorimeter and an accurate optical densitometer. The following parameters: mean power, mean current, mean energy/particle, pulse Width, pulse amplitude dispersion, and pulse frequency, operating the 2 MeV linear accelerator of CBPF (Brazilian Center pf Physics Researches). The optical isodensity curves of irradiated glass lamellae were obtained, providing information about focus degradation penetration direction in material and the reach of particle. The point to point dose distribution in the material from optical density curves were obtained, using a semi empirical and approached model. (M.C.K.)

  1. Staging optics considerations for a plasma wakefield acceleration linear collider

    Science.gov (United States)

    Lindstrøm, C. A.; Adli, E.; Allen, J. M.; Delahaye, J. P.; Hogan, M. J.; Joshi, C.; Muggli, P.; Raubenheimer, T. O.; Yakimenko, V.

    2016-09-01

    Plasma wakefield acceleration offers acceleration gradients of several GeV/m, ideal for a next-generation linear collider. The beam optics requirements between plasma cells include injection and extraction of drive beams, matching the main beam beta functions into the next cell, canceling dispersion as well as constraining bunch lengthening and chromaticity. To maintain a high effective acceleration gradient, this must be accomplished in the shortest distance possible. A working example is presented, using novel methods to correct chromaticity, as well as scaling laws for a high energy regime.

  2. Status of the Advanced Photon Source (APS) linear accelerator

    International Nuclear Information System (INIS)

    A 2856-MHz S-band, electron-positron linear accelerator (linac) has been constructed at the Advanced Photon Source (APS). It is the source of particles and the injector for the other APS accelerators, and linac commissioning is well underway. The linac is operated 24 hours per day to support linac beam studies and rf conditioning, as well as positron accumulator ring and synchrotron commissioning studies. The design goal for accelerated positron current is 8-mA, and has been met. Maximum positron energy to date is 420-MeV, approaching the design goal of 450-MeV. The linac design and its performance are discussed

  3. SLC status and SLAC [Stanford Linear Accelerator Center] future plans

    International Nuclear Information System (INIS)

    In this presentation, I shall discuss the linear collider program at the Stanford Linear Accelerator Center as it is now, and as we hope to see it evolve over the next few years. Of greatest interest to the high energy accelerator physics community gathered here is the development of the linear collider concept, and so I shall concentrate most of this paper on a discussion of the present status and future evolution of the SLC. I will also briefly discuss the research and development program that we are carrying out aimed at the realization of the next generation of high-energy linear colliders. SLAC had a major colliding-beam storage-ring program as well, including present rings and design studies on future high-luminosity projects, but time constraints preclude a discussion of them. 8 figs., 3 tabs

  4. The design of the accelerating gaps for the linear induction accelerator RADLAC II

    International Nuclear Information System (INIS)

    In high current (50 kA) linear induction accelerators, the accelerating gaps can excite large radial oscillations. A gap was designed that minimized the radial oscillations and reduced potential depressions. The envelope equation predicted radial oscillation amplitudes of 1 mm which agreed with experimental measurements

  5. Accelerating section of an electron linear accelerator of the 3 cm range

    International Nuclear Information System (INIS)

    The results of calculations of a portable linear accelerator of electrons with the minimum possible mass and dimensions are presented. The calculations are accomplished within the frames of the PARMELA and SUPERFISH programs. The dependences of the field relative velocity and intensity along the waveguide length are shown. The beam parameters at the accelerator outlet in dependence on the current load are also presented

  6. Independent checks of linear accelerators equipped with multileaf collimators

    International Nuclear Information System (INIS)

    National Radiation Protection Institute (NRPI) provides independent checks of therapeutic equipment as a part of state supervision. In the end of 2003, the audit was broaden for linear accelerators equipped with multileaf collimators (MLC). NRPI provides TLD postal audits and on-site independent checks. This contribution describes tests for multileaf collimators and intensity modulated radiation therapy (IMRT) technique that are accomplished within the independent on-site check of linear accelerators. The character and type of tests that are necessary to pursue for multileaf collimator depends on application technique. There are three basic application of the MLC. The first we call 'static MLC' and it serves for replacing conventional blocking or for adjusting the field shape to match the beam's-eye view projection of a planning target volume during an arc rotation of the x-ray beam. This procedure is called conformal radiotherapy. The most advanced technique with MLC is intensity modulated radiation therapy. The dose can be delivered to the patient with IMRT in various different ways: dynamic MLC, segmented MLC and IMRT arc therapy. Independent audits represent an important instrument of quality assurance. Methodology for independent check of static MLC was successfully verified on two types of accelerators: Varian and Elekta. Results from pilot measurements with dynamic MLC imply that the methodology is applicable for Varian accelerators. In the future, the experience with other types of linear accelerators will contribute to renovation, modification, and broaden independent checks methodology. (authors)

  7. Linear-accelerator-based stereotactic irradiation for metastatic brain tumors

    International Nuclear Information System (INIS)

    To assess the safety and availability of stereotactic radiotherapy (SRT) for metastatic brain tumors, we reviewed 54 consecutive cases with a total of 118 brain metastases treated with linear-accelerator-based stereotactic irradiation (STI). Nineteen patients with a total of 27 brain tumors that were larger than 3 cm or close to critical normal tissues were treated with SRT. The marginal dose of SRT was 15-21 Gy (median 21 Gy) in 3 fractions for 3 days. The median marginal dose of stereotactic radiosurgery (SRS) was 20 Gy. Effective rates of imaging studies were 72.7% and 94.4%, and those of clinical symptoms were 46.7% and 55.6% for SRT and SRS, respectively. One-year and two-year survival rates of SRT were 40.9% and 17.6%, respectively, and the median follow-up period was 6.4 months. The one-year survival rate of SRS was 32.7%, with a median follow-up of 4.6 months. Fourteen cases (7 cases each) had recurrent tumors at STI sites. Early complications were observed in one case of SRT and 8 cases of SRS, and late complications occurred in 3 cases of SRS. There were no significant differences among effective rates, survival rates, median follow-up times, recurrence rates, and complications between SRT and SRS. We concluded that SRT is a safe, effective therapy for large or eloquent area metastases. (author)

  8. Linear-accelerator-based stereotactic irradiation for metastatic brain tumors

    Energy Technology Data Exchange (ETDEWEB)

    Takemoto, Mitsuhiro; Katsui, Kuniaki; Yoshida, Atsushi [Okayama Univ. (Japan). School of Medicine] [and others

    2003-05-01

    To assess the safety and availability of stereotactic radiotherapy (SRT) for metastatic brain tumors, we reviewed 54 consecutive cases with a total of 118 brain metastases treated with linear-accelerator-based stereotactic irradiation (STI). Nineteen patients with a total of 27 brain tumors that were larger than 3 cm or close to critical normal tissues were treated with SRT. The marginal dose of SRT was 15-21 Gy (median 21 Gy) in 3 fractions for 3 days. The median marginal dose of stereotactic radiosurgery (SRS) was 20 Gy. Effective rates of imaging studies were 72.7% and 94.4%, and those of clinical symptoms were 46.7% and 55.6% for SRT and SRS, respectively. One-year and two-year survival rates of SRT were 40.9% and 17.6%, respectively, and the median follow-up period was 6.4 months. The one-year survival rate of SRS was 32.7%, with a median follow-up of 4.6 months. Fourteen cases (7 cases each) had recurrent tumors at STI sites. Early complications were observed in one case of SRT and 8 cases of SRS, and late complications occurred in 3 cases of SRS. There were no significant differences among effective rates, survival rates, median follow-up times, recurrence rates, and complications between SRT and SRS. We concluded that SRT is a safe, effective therapy for large or eloquent area metastases. (author)

  9. Status of the Advanced Photon Source (APS) linear accelerator

    International Nuclear Information System (INIS)

    A 2856-MHz S-band, 450-MeV electron/positron linear accelerator is the first part of the injector for the Advanced Photon Source (APS) 7-GeV storage ring. Construction of the APS linac is currently nearing completion, and commissioning will begin in July 1993. The linac and its current status are discussed in this paper

  10. Annotated bibliography on high-intensity linear accelerators

    International Nuclear Information System (INIS)

    A technical bibliography covering subjects important to the design of high-intensity beam transport systems and linear accelerators is presented. Space charge and emittance growth are stressed. Subject and author concordances provide cross-reference to detailed citations, which include an abstract and notes on the material. The bibliography resides in a computer database that can be searched for key words and phrases

  11. Spin dynamics in storage rings and linear accelerators

    International Nuclear Information System (INIS)

    The purpose of these lectures is to survey the subject of spin dynamics in accelerators: to give a sense of the underlying physics, the typical analytic and numeric methods used, and an overview of results achieved. Consideration will be limited to electrons and protons. Examples of experimental and theoretical results in both linear and circular machines are included

  12. Code of practice for x-ray therapy linear accelerators

    International Nuclear Information System (INIS)

    Details are presented on the tests that should be performed during the installation of a megavoltage linear accelerator. Also discussed are the dosimetry studies that should be done as part of the operation of the machine. Information in specific radiation monitoring equipment is provided. (U.S.)

  13. Annotated bibliography on high-intensity linear accelerators. [240 citations

    Energy Technology Data Exchange (ETDEWEB)

    Jameson, R.A.; Roybal, E.U.

    1978-01-01

    A technical bibliography covering subjects important to the design of high-intensity beam transport systems and linear accelerators is presented. Space charge and emittance growth are stressed. Subject and author concordances provide cross-reference to detailed citations, which include an abstract and notes on the material. The bibliography resides in a computer database that can be searched for key words and phrases.

  14. Transient beam loading compensation in traveling wave linear accelerators

    International Nuclear Information System (INIS)

    For normal conducting linear colliders the transient beam loading in the accelerating structures is typically of the order of 20-30%. This results in a multibunch energy spread of the same magnitude if no remedy is taken into account. On the other hand, in a linear collider the transient energy spread has to be controlled down to a few tenth of a percent. Two possible methods, assuming two different setups, e.g. klystron plus structure and klystron plus SLED cavity plus structure, are investigated. A description of the whole rf system and the resulting energy spread is presented especially for the case of the S-Band linear collider study. (orig.)

  15. linear accelerator simulation framework with placet and guinea-pig

    CERN Document Server

    Snuverink, Jochem; CERN. Geneva. ATS Department

    2016-01-01

    Many good tracking tools are available for simulations for linear accelerators. However, several simple tasks need to be performed repeatedly, like lattice definitions, beam setup, output storage, etc. In addition, complex simulations can become unmanageable quite easily. A high level layer would therefore be beneficial. We propose LinSim, a linear accelerator framework with the codes PLACET and GUINEA-PIG. It provides a documented well-debugged high level layer of functionality. Users only need to provide the input settings and essential code and / or use some of the many implemented imperfections and algorithms. It can be especially useful for first-time users. Currently the following accelerators are implemented: ATF2, ILC, CLIC and FACET. This note is the comprehensive manual, discusses the framework design and shows its strength in some condensed examples.

  16. Proceedings of the 18. international linear accelerator conference. Vol. 2

    International Nuclear Information System (INIS)

    These proceedings cover the whole field of linear accelerators, from its original and continuing role in particle physics research to the wide range of applications found today in many other disciplines and technologies. The contributions were deliberately spread among the different conference sessions in order to maintain a broad interest. The topics covered include: the design, construction and control of linear accelerators and the associated technology; dedicated test facilities, injection, wakefields, bunching, halo, dynamics, radio-frequency (RF), electron and ion accelerators, (laser) ion sources; active alignment, beam steering and spot size; simulation, monitoring and diagnostics; a description of the performance and current status of many machines, including proposed ones such as CLIC, the NLC and TESLA; applications to medical diagnosis and radiotherapy; use in the treatment and sterilisation of materials (including food) and in the reprocessing of radioactive waste; use as potential suppliers of energy. (orig.)

  17. A study of neutron output from a medical linear accelerator

    International Nuclear Information System (INIS)

    In recent years, medical linear accelerators of higher energies (E>10 MeV) are becoming of common use in Brazil and the National Nuclear Energy Commission (CNEN) is facing the problem of licensing these Radiative Facilities. The question of how to shield these rooms, considering the neutron output from these machines, is not trivial. Many empirical models suggest how to calculate the neutron dose equivalent due to these particles, which are mainly produced trough (g,n) reactions in the accelerator head. In this article we present some measurements of neutrons produced by a 18 MeV Varian CLINAC 2100C linear accelerator at the Albert Einstein Hospital, in Sao Paulo, Brazil. The results are compared with theoretical calculations based on empirical models as well as on the equations presented in NCRP 79. (author)

  18. Computer Based Dose Control System on Linear Accelerator

    International Nuclear Information System (INIS)

    The accelerator technology has been used for radio therapy. DokterKaryadi Hospital in Semarang use electron or X-ray linear accelerator (Linac)for cancer therapy. One of the control parameter of linear accelerator isdose rate. It is particle current or amount of photon rate to the target. Thecontrol of dose rate in linac have been done by adjusting repetition rate ofanode pulse train of electron source. Presently the control is stillproportional control. To enhance the quality of the control result (minimalstationer error, velocity and stability), the dose control system has beendesigned by using the PID (Proportional Integral Differential) controlalgorithm and the derivation of transfer function of control object.Implementation of PID algorithm control system is done by giving an input ofdose error (the different between output dose and dose rate set point). Theoutput of control system is used for correction of repetition rate set pointfrom pulse train of electron source anode. (author)

  19. Total body irradiation with a 10 MV linear accelerator in conjunction with bone marrow transplantation

    International Nuclear Information System (INIS)

    Total body irradiation (1000 rad, single dose) in conjunction with chemotherapy and bone marrow transplantation is a therapy for acute leukemia. We show that a 10 MV linear accelerator is a suitable source of radiation for these procedures. Dosimetric and clinical results are presented for 25 patients who were treated between 5/76 and 12/78

  20. Separated-orbit bisected energy-recovered linear accelerator

    Science.gov (United States)

    Douglas, David R.

    2015-09-01

    A separated-orbit bisected energy-recovered linear accelerator apparatus and method. The accelerator includes a first linac, a second linac, and a plurality of arcs of differing path lengths, including a plurality of up arcs, a plurality of downgoing arcs, and a full energy arc providing a path independent of the up arcs and downgoing arcs. The up arcs have a path length that is substantially a multiple of the RF wavelength and the full energy arc includes a path length that is substantially an odd half-integer multiple of the RF wavelength. Operation of the accelerator includes accelerating the beam utilizing the linacs and up arcs until the beam is at full energy, at full energy executing a full recirculation to the second linac using a path length that is substantially an odd half-integer of the RF wavelength, and then decelerating the beam using the linacs and downgoing arcs.

  1. LUER-20M medical linear accelerator of electrons. Adjustment experience and applications

    International Nuclear Information System (INIS)

    On the basis of the experience using accelerators, made earlier, and radiologists recommendations a series of the LUER-20M medical linear accelerators of electrons with the Bremsstrahlung quanta of 6 and 18 MeV and electron energy of 5, 8, 11, 14, 17 and 20 MeV is developed. The accelerator assures a complete radiotherapy course under specialized clinics conditions in the static and rotational modes with manual and remote control. It may also be used for medical and biological investigations

  2. 9th International Accelerator School for Linear Colliders

    CERN Document Server

    2015-01-01

    This school is a continuation of the series of schools that began nine years ago: Japan 2006, Italy 2007, United States 2008, China 2009, Switzerland 2010, United States 2011, India 2012 and Turkey 2013. Based on needs from the accelerator community, the Linear Collider Collaboration (LCC) and ICFA Beam Dynamics Panel are organising the Ninth International Accelerator School for Linear Colliders. The school will present instruction in TeV-scale linear colliders including the ILC, CLIC and other advanced accelerators. An important change of this year’s school from previous LC schools is that it will also include the free electron laser (FEL), a natural extension for applications of the ILC/CLIC technology. The school is offered to graduate students, postdoctoral fellows and junior researchers from around the world. We welcome applications from physicists who are considering changing to a career in accelerator physics and technology. This school adopts an in depth approach. A selective course on the FEL has b...

  3. Next Linear Collider Test Accelerator conceptual design report

    International Nuclear Information System (INIS)

    This document presents the scientific justification and the conceptual design for the open-quotes Next Linear Collider Test Acceleratorclose quotes (NLCTA) at SLAC. The goals of the NLCTA are to integrate the new technologies of X-band accelerator structures and rf systems being developed for the Next Linear Collider, to measure the growth of the open-quotes dark currentclose quotes generated by rf field emission in the accelerator, to demonstrate multi-bunch beam-loading energy compensation and suppression of higher-order deflecting modes, and to measure any transverse components of the accelerating field. The NLCTA will be a 42-meter-long beam line consisting, consecutively, of a thermionic-cathode gun, an X-band buncher, a magnetic chicane, six 1.8-meter-long sections of 11.4-GHz accelerator structure, and a magnetic spectrometer. Initially, the unloaded accelerating gradient will be 50 MV/m. A higher-gradient upgrade option eventually would increase the unloaded gradient to 100 MV/m

  4. Klystron pulse modulator of linear electron accelerator: test results

    Directory of Open Access Journals (Sweden)

    Z. Zimek

    2009-12-01

    Full Text Available Purpose: The purpose of the paper is to describe Klystron pulse modulator of linear electron accelerator.Design/methodology/approach: TH-2158 klystron modulator experimental model is based on semiconductor switch HTS 181-160 FI (acceptable current load 1600 A, and voltage up to 18 kV. The results of test measurements carried out during modulator starting up period are presented in this work. TH-2158 klystron was used as a load. The klystron was connected to the second winding of the pulse HV transformer with 1:10 windings turn ratio. The examined modulator is equipped with safety shutdown circuitry for protection against current overload that may appear at IGBT switch in the case of short-circuiting happened in klystron and waveguide system.Findings: Linear electron accelerator type LAE 10/15 with electron energy 10 MeV and beam power up to 15 kW was designed and completed at Institute of Nuclear Chemistry and Technology. This accelerator was installed in facility for radiation sterilization single use medical devices, implants and tissue grafts. The standing wave accelerating section was selected. Microwave energy used for accelerating process is provided by klystron type TH-2158 working at frequency 2856 MHz.Practical implications: Described HV pulse modulator which designed and constructed for klystron TH-2158 was preliminary tested to evaluate the quality of the klystron HV and load current pulses and optimized selected component parameters. Obtained experimental results are better than those which were predicted by computer simulation method.Originality/value: Description of Klystron pulse modulator of linear electron accelerator.

  5. Present status of linear induction accelerator development at BARC

    International Nuclear Information System (INIS)

    A Linear Induction Electron Accelerator of rating- 200 keV, 5 kA, 100ns, 10-100 Hz, is in the advanced stage of commissioning at Bhabha Atomic Research Centre. This paper presents a few experimental results while developing the various sub-systems of this accelerator. It comprises of 3-stage induction cavities, solid state modulator based command resonant charging system with high power SCR switching in 10-100 Hz to amorphous core based 2.5 kV/20 kV, 20μs pulse transformer, magnetic switches and DC choke along with 100 A DC reset current systems. (author)

  6. 8th International Accelerator School for Linear Colliders

    CERN Document Server

    2013-01-01

    This school is a continuation of the series of schools started six years ago (2006 in Japan, 2007 in Italy, 2008 in the U.S., 2009 in China, 2010 in Switzerland, 2011 in the U.S. and 2012 in India). Based on the needs from the high-energy physics community, the Linear Collider Collaboration (LCC) and ICFA Beam Dynamics Panel will organise an Eighth International Accelerator School for Linear Colliders. The focus of the school will be on TeV-scale linear colliders including the International Linear Collider (ILC), the Compact Linear Collider (CLIC) and other advanced colliders. The target students are graduate students, postdoctoral fellows and junior researchers from around the world. We welcome applications from physicists who are considering changing their career from experimental physics to accelerator physics. This school is adopting an in depth approach. Therefore, former students are welcome to apply if they have a compelling reason to do so. The school will be in lecture style. There will be homework a...

  7. Phase and amplitude detection system for the Stanford Linear Accelerator

    International Nuclear Information System (INIS)

    A computer controlled phase and amplitude detection system to measure and stabilize the rf power sources in the Stanford Linear Accelerator is described. This system measures the instantaneous phase and amplitude of a 1 microsecond 2856 MHz rf pulse and will be used for phase feedback control and for amplitude and phase jitter detection. This paper discusses the measurement system performance requirements for the operation of the Stanford Linear Collider, and the design and implementation of the phase and amplitude detection system. The fundamental software algorithms used in the measurement are described, as is the performance of the prototype phase and amplitude detector system

  8. Linear accelerator radiosurgery for trigeminal neuralgia: case report

    International Nuclear Information System (INIS)

    Trigeminal neuralgia is defined as an episodic electrical shock-like sensation in a dermatomal distribution of the trigeminal nerve. When medications fail to control pain, various procedures are used to attempt to control refractory pain. Of available procedures, stereotactic radiosurgery is the least invasive procedure and has been demonstrated to produce significant pain relief with minimal side effects. Recently, linear accelerators were introduced as a tool for radiosurgery of trigeminal neuralgia beneath the already accepted gamma unit. Author have experienced one case with trigeminal neuralgia treated with linear accelerator. The patient was treated with 85 Gy by means of 5 mm collimator directed to trigeminal nerve root entry zone. The patient obtained pain free without medication at 20 days after the procedure and remain pain free at 6 months after the procedure. He didn't experience facial numbness or other side effects

  9. Linear accelerator radiosurgery for trigeminal neuralgia: case report

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Hyong Geun [Dongguk University International Hospital, Goyang (Korea, Republic of)

    2006-06-15

    Trigeminal neuralgia is defined as an episodic electrical shock-like sensation in a dermatomal distribution of the trigeminal nerve. When medications fail to control pain, various procedures are used to attempt to control refractory pain. Of available procedures, stereotactic radiosurgery is the least invasive procedure and has been demonstrated to produce significant pain relief with minimal side effects. Recently, linear accelerators were introduced as a tool for radiosurgery of trigeminal neuralgia beneath the already accepted gamma unit. Author have experienced one case with trigeminal neuralgia treated with linear accelerator. The patient was treated with 85 Gy by means of 5 mm collimator directed to trigeminal nerve root entry zone. The patient obtained pain free without medication at 20 days after the procedure and remain pain free at 6 months after the procedure. He didn't experience facial numbness or other side effects.

  10. Beam dynamics in a long-pulse linear induction accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Carl [Los Alamos National Laboratory; Abeyta, Epifanio O [Los Alamos National Laboratory; Aragon, Paul [Los Alamos National Laboratory; Archuleta, Rita [Los Alamos National Laboratory; Cook, Gerald [Los Alamos National Laboratory; Dalmas, Dale [Los Alamos National Laboratory; Esquibel, Kevin [Los Alamos National Laboratory; Gallegos, Robert A [Los Alamos National Laboratory; Garnett, Robert [Los Alamos National Laboratory; Harrison, James F [Los Alamos National Laboratory; Johnson, Jeffrey B [Los Alamos National Laboratory; Jacquez, Edward B [Los Alamos National Laboratory; Mc Cuistian, Brian T [Los Alamos National Laboratory; Montoya, Nicholas A [Los Alamos National Laboratory; Nath, Subrato [Los Alamos National Laboratory; Nielsen, Kurt [Los Alamos National Laboratory; Oro, David [Los Alamos National Laboratory; Prichard, Benjamin [Los Alamos National Laboratory; Rose, Chris R [Los Alamos National Laboratory; Sanchez, Manolito [Los Alamos National Laboratory; Schauer, Martin M [Los Alamos National Laboratory; Seitz, Gerald [Los Alamos National Laboratory; Schulze, Martin [Los Alamos National Laboratory; Bender, Howard A [Los Alamos National Laboratory; Broste, William B [Los Alamos National Laboratory; Carlson, Carl A [Los Alamos National Laboratory; Frayer, Daniel K [Los Alamos National Laboratory; Johnson, Douglas E [Los Alamos National Laboratory; Tom, C Y [Los Alamos National Laboratory; Trainham, C [Los Alamos National Laboratory; Williams, John [Los Alamos National Laboratory; Scarpetti, Raymond [LLNL; Genoni, Thomas [VOSS; Hughes, Thomas [VOSS; Toma, Carsten [VOSS

    2010-01-01

    The second axis of the Dual Axis Radiography of Hydrodynamic Testing (DARHT) facility produces up to four radiographs within an interval of 1.6 microseconds. It accomplishes this by slicing four micro-pulses out of a long 1.8-kA, 16.5-MeV electron beam pulse and focusing them onto a bremsstrahlung converter target. The long beam pulse is created by a dispenser cathode diode and accelerated by the unique DARHT Axis-II linear induction accelerator (LIA). Beam motion in the accelerator would be a problem for radiography. High frequency motion, such as from beam breakup instability, would blur the individual spots. Low frequency motion, such as produced by pulsed power variation, would produce spot to spot differences. In this article, we describe these sources of beam motion, and the measures we have taken to minimize it.

  11. Occupational dose due to neutrons in medical linear accelerators

    International Nuclear Information System (INIS)

    This paper describes a semi-empirical method to calculate the occupational dose due to neutrons and capture gamma rays in medical linear accelerators. It compares theoretical dose values with measurements performed in several 15 MeV medical accelerators installed in the country. Good agreement has been found between calculations made using the model and dose measurements, except for those accelerator rooms in which the maze length was shorter than the postulated tenth value distance. For those cases the model seems to overestimate neutron dose. The results demonstrate that the semi-empirical model is a good tool for quick and conservative shielding calculations for radiation protection purposes. Nevertheless, it is necessary to continue with the measurements in order to perform a more accurate validation of the model. (author)

  12. Non-linear Particle Acceleration in Oblique Shocks

    CERN Document Server

    Ellison, D C; Jones, F C; Ellison, Donald C.; Baring, Matthew G.; Jones, Frank C.

    1996-01-01

    We have developed a Monte Carlo technique for self-consistently calculating the hydrodynamic structure of oblique, steady-state shocks, together with the first-order Fermi acceleration process and associated non-thermal particle distributions. This is the first internally consistent treatment of modified shocks that includes cross-field diffusion of particles. Our method overcomes the injection problem faced by analytic descriptions of shock acceleration, and the lack of adequate dynamic range and artificial suppression of cross-field diffusion faced by plasma simulations; it currently provides the most broad and versatile description of collisionless shocks undergoing efficient particle acceleration. We present solutions for plasma quantities and particle distributions upstream and downstream of shocks, illustrating the strong differences observed between non-linear and test-particle cases. It is found that there are only marginal differences in the injection efficiency and resultant spectra for two extreme ...

  13. Beam dynamics in a long-pulse linear induction accelerator

    International Nuclear Information System (INIS)

    The second axis of the Dual Axis Radiography of Hydrodynamic Testing (DARHT) facility produces up to four radiographs within an interval of 1.6 microseconds. It accomplishes this by slicing four micro-pulses out of a long 1.8-kA, 16.5-MeV electron beam pulse and focusing them onto a bremsstrahlung converter target. The long beam pulse is created by a dispenser cathode diode and accelerated by the unique DARHT Axis-II linear induction accelerator (LIA). Beam motion in the accelerator would be a problem for radiography. High frequency motion, such as from beam breakup instability, would blur the individual spots. Low frequency motion, such as produced by pulsed power variation, would produce spot to spot differences. In this article, we describe these sources of beam motion, and the measures we have taken to minimize it.

  14. Outcome of cerebral arteriovenous malformations after linear accelerator reirradiation

    Directory of Open Access Journals (Sweden)

    Paulo L Moraes

    2015-01-01

    Full Text Available Background: The aim of this study was to evaluate the clinical outcome of patients undergoing single-dose reirradiation using the Linear Accelerator (LINAC for brain arteriovenous malformations (AVM. Methods: A retrospective study of 37 patients with brain AVM undergoing LINAC reirradiation between April 2003 and November 2011 was carried out. Patient characteristics, for example, gender, age, use of medications, and comorbidities; disease characteristics, for example, Spetzler-Martin grading system, location, volume, modified Pollock-Flickinger score; and treatment characteristics, for example, embolization, prescription dose, radiation dose-volume curves, and conformity index were analyzed. During the follow-up period, imaging studies were performed to evaluate changes after treatment and AVM cure. Complications, such as edema, rupture of the blood-brain barrier, and radionecrosis were classified as symptomatic and asymptomatic. Results: Twenty-seven patients underwent angiogram after reirradiation and the percentage of angiographic occlusion was 55.5%. In three patients without obliteration, AVM shrinkage made it possible to perform surgical resection with a 2/3 cure rate. A reduction in AVM nidus volume greater than 50% after the first procedure was shown to be the most important predictor of obliteration. Another factor associated with AVM cure was a prescription dose higher than 15.5 Gy in the first radiosurgery. Two patients had permanent neurologic deficits. Factors correlated with complications were the prescription dose and maximum dose in the first procedure. Conclusion: This study suggests that single-dose reirradiation is safe and feasible in partially occluded AVM. Reirradiation may not benefit candidates whose prescribed dose was lower than 15.5 Gy in the first procedure and initial AVM nidus volume did not decrease by more than 50% before reirradiation.

  15. Electromagnetic field measurements on a mm-wave linear accelerator

    International Nuclear Information System (INIS)

    Field strength measurements for the determination of the R/Q of a mm-wave, 50-MeV electron linear accelerator using perturbational techniques are described. The perturbation is achieved using optical fibers coated with a thin metallic film to form a hollow cylinder. The perturbational form factors for such a geometry are approximated using several simple analytical expressions which are compared to a finite difference calculation as well as experimental results on a known cavity

  16. Dosimetric comparison of linear accelerator-based stereotactic radiosurgery systems

    OpenAIRE

    Sharma S; Kumar Sudhir; Dagaonkar S; Bisht Geetika; Dayanand S; Devi Reena; Deshpande S; Chaudhary S; Bhatt B; Kannan S

    2007-01-01

    Stereotactic radiosurgery (SRS) is a special radiotherapy technique used to irradiate intracranial lesions by 3-D arrangements of narrow photon beams eliminating the needs of invasive surgery. Three different tertiary collimators, namely BrainLab and Radionics circular cones and BrainLab micro multileaf collimator (mMLC), are used for linear accelerator-based SRS systems (X-Knife). Output factor (St), tissue maximum ratio (TMR) and off axis ratio (OAR) of these three SRS systems were measured...

  17. Treatment of Cavernous Sinus Tumors with Linear Accelerator Radiosurgery

    OpenAIRE

    Chang, Steven D; Doty, James R; Martin, David P.; Hancock, Steven L.; Adler, John R.

    1999-01-01

    Since 1989, 79 patients with benign or malignant cavernous sinus tumors, have been treated at Stanford University with linear accelerator (linac) radiosurgery. Radiosurgery has been used as (1) a planned second-stage procedure for residual tumor following surgery, (2) primary treatment for patients whose medical conditions preclude surgery, (3) palliation of malignant lesions, and (4) definitive treatment for small, well-localized, poorly accessible tumors. Mean patient age was 52 years (rang...

  18. Monitoring and control system of the Saclay electron linear accelerator

    International Nuclear Information System (INIS)

    A description is given of the automatic monitoring and control system of the 60MeV electron linear accelerator of the Centre d'Etudes Nucleaires de Saclay. The paper is mostly concerned with the programmation of the system. However, in a real time device, there is a very close association between computer and electronics, the latter are therefore described in details and make up most of the paper.

  19. Organizational cultural survey of the Stanford Linear Accelerator Center

    Energy Technology Data Exchange (ETDEWEB)

    1991-11-01

    At the request of the Department of Energy, an Organizational Survey (OS) was administered at the Stanford Linear Accelerator Center (SLAC). The OS measured employees' opinions on subjects such as organizational culture, communication, commitment, group cohesion, coordination, safety, environmental issues, and job satisfaction. The result of this work was a quantitative measure of the notion of culture at the SLAC site. This report presents these results and discusses their interpretation.

  20. Superpower proton linear accelerators for neutron generators and electronuclear facilities

    International Nuclear Information System (INIS)

    The report is a review of projects on the superpower proton linear accelerators (SPLA) for neutron generators (NG) and electronuclear facilities, proposed in the recent years. The beam average output capacity in these projects reaches 100 MW. The basic parameters of certain operating NGs, as well as some projected NGs will the SPLA drivers are presented. The problems on application of superconducting resonators in the SPLA as well as the issues of the SPLA reliability and costs are discussed

  1. Linear induction accelerator and pulse forming networks therefor

    Science.gov (United States)

    Buttram, Malcolm T.; Ginn, Jerry W.

    1989-01-01

    A linear induction accelerator includes a plurality of adder cavities arranged in a series and provided in a structure which is evacuated so that a vacuum inductance is provided between each adder cavity and the structure. An energy storage system for the adder cavities includes a pulsed current source and a respective plurality of bipolar converting networks connected thereto. The bipolar high-voltage, high-repetition-rate square pulse train sets and resets the cavities.

  2. Radio-frequency quadrupole: a new linear accelerator

    International Nuclear Information System (INIS)

    In many Laboratories, great emphasis now is placed on the development of linear accelerators with very large ion currents. To achieve this goal, a primary concern must be the low-velocity part of the accelerator, where the current limit is determined and where most of the emittance growth occurs. The use of magnetic focusing, the conflicting requirements in the choice of linac frequency, and the limitations of high-voltage dc injectors, have tended to produce low-velocity designs that limit overall performance. The radio-frequency quadrupole (RFQ) linear accelerator, invented in the Soviet Union and developed at Los Alamos, offers an attractive solution to many of these low-velocity problems. In the RFQ, the use of RF electric fields for radial focusing, combined with special programming of the bunching, allows high-current dc beams to be captured and accelerated with only small beam loss and low radial emittance growth. Advantages of the RFQ linac include a low injection energy (20 to 50 keV for protons) and a final energy high enough so the beam can be further accelerated with high efficiency in a Wideroee or Alvarez linac. These properties have been confirmed at Los Alamos in a highly successful experimental test performed during the past year. The success of this test and the advances in RFQ design procedures have led to the adoption of this linac for a wide range of applications. The beam-dynamics parameters of three RFQ systems are described. These are the final design for the protytype test of the Fusion Materials Irradiation Test (FMIT) accelerator, the final design for the prototype test of the Pion Generator for Medical Irradiations (PIGMI), and an improved low-velocity linac for heavy ion fusion

  3. Occupational doses due to photoneutrons in medical linear accelerators rooms

    International Nuclear Information System (INIS)

    Medical linear accelerators, with maximum photon energies above 10 MeV, are becoming of common use in Brazil. Although desirable in the therapeutic point of view, the increase in photon energies causes the generation of undesired neutrons, which are produced through nuclear reactions between photons and the high Z target nuclei of the materials that constitute the accelerator head. In this work, MCNP simulation was undertaken to examine the neutron equivalent doses around the accelerators head and at the entrance of medical linear accelerators treatment rooms, some of them licensed in Brazil by the National Regulatory Agency (CNEN). The simulated neutron dose equivalents varied between 2 e 26 μ Sv/GyRX, and the results were compared with calculations performed with the use of some semi-empirical equations found in literature. It was found that the semi-empirical equations underestimate the simulated neutron doses in the majority of the cases, if compared to the simulated values, suggesting that these equations must be revised, due to the increasing number of high energy machines in the country. (author)

  4. Quality assurance for stereotactic radiosurgery using linear accelerator

    International Nuclear Information System (INIS)

    Stereotactic radiosurgery using a linear accelerator requires two quality assurance items; positional accuracy of irradiation and its prescribed dose. Authors have evaluated these two items in the QA program. To evaluate the positional accuracy of irradiation, the alignment of a laser pointer was measured at a isocenter using a target point simulator. The positional accuracy of the gantry and couch rotations of the linear accelerator was evaluated by the 'star shot' method. As to the dose measurement, tissue maximum ratio, off axis ratio, and relative output factor were determined using a diamond detector. Since a laser pointer is susceptible to small vibrations, it should always be checked. The results indicated that the positional accuracy of the gantry and couch rotations must be maintained within 1.0 mm for 360 degrees. As to the dose measurement, TMR, OAR, and ROF should be measured regularly by a small-sized detector with a high sensitivity and low-energy dependance such as a diamond detector. Stereotactic radiosurgery using a linear accelerator requires a QA program. Among other maintenance items in this QA program, the positional accuracy of gantry and couch rotation should be maintained within 1.0 mm for 360 degrees. (author)

  5. Problems of optimization of the accelerating system parameters of induction linear accelerators

    International Nuclear Information System (INIS)

    Optimization of the accelerating system of an induction linear accelerator (ILAC) is discussed. For computerized optimization of ILAC parameters, analytical dependences are required which relate accelerator elements to its operating conditions. In deriving the objective function the degree of importance of optimized parameters is taken account of in the weight factors whose value can vary from 0 to 1. One minimum in the objective function permitted the employment of a simple algorithm for optimization - the gradient method. In optimization it is assumed that most common criteria for estimating the ILAC are the efficiency, the relative cost, and the specific energy capacity

  6. Control and accelerating voltage automatic pulse acquisition system for ''LIU-5/5000'' linear accelerators

    International Nuclear Information System (INIS)

    A system prowiding continuous control and automatic correction of actuation of accelerating voltage pulse generators of a linear induction accelerator is described. TGI-2500/50 thyratrons are switching elements of the generators. Shaped pulses have a bell form, their duration on the foundation constitues 300 ns. The device operation is based on the determination of a sign of time error between generator and reference pulses. Depending on the error sign performed is correction of the delay value included into the actuation circuit of the corresponding generator. Such operation is accomplished in each working pulse of the accelerator. Data on the delay condition go to the digital panel and digital print-out. Technical characteristics of the system are the following: 56 cynchronization channels, 155 ns control interval, 5 ns control pitch, error of the error determination is not worse than +-2.5 ns. The system permitted to improve accelerated beam stability and to simplify accelerator tuning and control

  7. Radiation protection in large linear accelerators; Seguranca radiologica de aceleradores lineares de grande porte

    Energy Technology Data Exchange (ETDEWEB)

    Oliva, Jose de Jesus Rivero, E-mail: rivero@con.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Departamento de Engenharia Nuclear; Sousa, Fernando Nuno Carneiro de, E-mail: fernandonunosousa@gmail.com [Aceletron Irradiacao lndustrial, Rio de Janeiro, RJ (Brazil)

    2013-07-01

    The electron linear accelerators can be used in industrial applications that require powerful sources of ionizing radiation. They have the important characteristic of not representing a radiation hazard when the accelerators remain electrically disconnected. With the plant in operation, a high reliability defense in depth reduces the risk of radiological accidents to extremely small levels. It is practically impossible that a person could enter into the radiation bunker with the accelerators connected. Aceletron Irradiacao Industrial, located in Rio de Janeiro, offers services of irradiation by means of two powerful electron linear accelerators, with 15 kW power and 10 MeV electron energy. Despite the high level of existing radiation safety, a simplified risk study is underway to identify possible sequences of radiological accidents. The study is based on the combined application of the event and fault trees techniques. Preliminary results confirm that there is a very small risk of entering into the irradiation bunker with the accelerators in operation, but the risk of an operator entering into the bunker during a process interruption and remaining there without notice after the accelerators were restarted may be considerably larger. Based on these results the Company is considering alternatives to reduce the likelihood of human error of this type that could lead to a radiological accident. The paper describes the defense in depth of the irradiation process in Aceletron Irradiacao Industrial, as well as the models and preliminary results of the ongoing risk analysis, including the additional safety measures which are being evaluated. (author)

  8. Control system analysis for the perturbed linear accelerator rf system

    CERN Document Server

    Sung Il Kwon

    2002-01-01

    This paper addresses the modeling problem of the linear accelerator RF system in SNS. Klystrons are modeled as linear parameter varying systems. The effect of the high voltage power supply ripple on the klystron output voltage and the output phase is modeled as an additive disturbance. The cavity is modeled as a linear system and the beam current is modeled as the exogenous disturbance. The output uncertainty of the low level RF system which results from the uncertainties in the RF components and cabling is modeled as multiplicative uncertainty. Also, the feedback loop uncertainty and digital signal processing signal conditioning subsystem uncertainties are lumped together and are modeled as multiplicative uncertainty. Finally, the time delays in the loop are modeled as a lumped time delay. For the perturbed open loop system, the closed loop system performance, and stability are analyzed with the PI feedback controller.

  9. An examination of medical linear accelerator ion-chamber performance

    International Nuclear Information System (INIS)

    Full text: The company ( Radiation Oncology Physics and Engineering Services Pty Ltd) provides medical physics services to four radiotherapy centres in NSW with a total of 6 high energy medical linear accelerators manufactured by three different companies. As part of the services, the stability of the accelerator ion chamber system is regularly examined for constancy and periodically for absolute calibration. Each accelerator ion chamber has exhibited undesirable behaviour from time to time, sometimes leading to its replacement. This presentation describes the performance of the ion chambers for some of the linacs over a period of 12-18 months and the steps taken by the manufacturer to address the problems encountered. As part of our commissioning procedure of new linacs, an absolute calibration of the accelerator output (photon and electron beams) is repeated several times over the period following examination of the physical properties of the radiation beams. These calibrations were undertaken in water using the groups calibrated ion chamber/electrometer system and were accompanied by constancy checks using an acrylic phantom and field instruments. Constancy checks were performed daily for a period of 8 weeks during the initial life of the accelerator and thereafter weekly. For one accelerator, the ion chamber was replaced 6 times in the first eighteen months of its life due to severe drifts in output, found to be due to pressure changes in one half of the chamber In another accelerator, erratic swings of 2% were observed for a period of nine months, particularly with the electron beams, before the manufacturer offered to change the chamber with another constructed from different materials. In yet another accelerator the ion chamber has shown consistent erratic behaviour, but this has not been addressed by the manufacturer. In another popular accelerator, the dosimetry was found to be very stable until some changes in the tuning were introduced resulting in small

  10. Stanford Linear Accelerator Center pulsed x-ray facility

    International Nuclear Information System (INIS)

    The Stanford Linear Accelerator Center (SLAC) operates a high-energy (up to 33 GeV) linear accelerator delivering pulses up to a few microseconds wide. The pulsed nature of the electron beam creates problems in the detection and measurement of radiation both from the accelerator beam and the klystrons that provide the radio-frequency power for the accelerator. Hence, a pulsed x-ray facility has been built at SLAC mainly for testing the response of different radiation detection instruments to pulsed radiation fields. The x-ray tube consists of an electron gun with a control grid. This provides a stream of pulsed electrons that can be accelerated towards a confined target window. The window consists of Al 0.051 cm (20 mils) thick, plated on the vacuum side with a layer of Au 0.0006 cm (1/4 mil) thick. The frequency of electron pulses can be varied by an internal pulser from 60 to 360 pulses per second with pulse widths of 360 ns to 5 microseconds. The pulse amplitude can be varied over a wide range of currents. An external pulser can be used to obtain other frequencies or special pulse shapes. The voltage across the gun can be varied from 0 to 100 kV. The maximum absorbed dose rate obtained at 6.35 cm below the target window as measured by an ionization chamber is 258 Gy/h. The major part of the x-ray tube is enclosed in a large walk-in cabinet made of 1.9-cm-thick (3/4-inch-thick) plywood and lined with 0.32-cm-thick (1/8-inch-thick) Pb to make a very versatile facility

  11. Low power RF measurements of travelling wave type linear accelerator

    International Nuclear Information System (INIS)

    RRCAT is engaged in the development of travelling wave (TW) type linear accelerator for irradiation of industrial and agricultural products. TW accelerator designed for 2π/3 mode to operate at frequency of 2856 MHz. It consists of input coupler, buncher cells, regular cells and output coupler. Low power measurement of this structure includes measurement of resonant frequency of the cells for different resonant modes and quality factor, tuning of input-output coupler and measurement of phase advance per cell and electric field in the structure. Steele's non-resonant perturbation technique has been used for measurement of phase advance per cell and electric field in the structure. Kyhl's method has been used for the tuning of input-output coupler. Computer based automated bead pull set-up has been developed for measurement of phase advance per cell and electric field profile in the structure. All the codes are written in Python for interfacing of Vector Network Analyzer (VNA) , stepper motor with computer. These codes also automate the measurement process. This paper describes the test set- up for measurement and results of measurement of travelling wave type linear accelerating structure. (author)

  12. Use of a detector CZT for verification of shields against neutron in 3 linear accelerators in clinical use; Uso de un detector CZT para la verificacion de blindajes frente a neutrones en 3 aceleradores lineales de uso clinico

    Energy Technology Data Exchange (ETDEWEB)

    Barquero Sanz, R.; Anton, D. A.; Iniguez de la Torre, P. L.; Castillo Belmonte, A. C. del; Alonso, D. A.; Miguel, D. M. de; Lopez Lara-Martin, F. L.

    2013-07-01

    This paper describes how to use the reaction of thermal neutrons (n?) {sup 1}13Cd, {sup 1}14 Cd with the cadmium in an alloy of cadmium and zinc Telluride (CZT) semiconductor detector. 558 keV photons produced can be detected by the own semiconductor. In this way have an agile method for the measurement of the neutron flux transmitted by shielding and which provides an almost immediate reading of the result. This method applies three accelerators linear in that checks the correct shield on their respective treatment rooms. (Author)

  13. Radiological safety aspects of the operation of electron linear accelerators

    International Nuclear Information System (INIS)

    This manual is intended as a guide for the planning and implementation of radiation protection programmes for all types of electron linear accelerators. Material is provided for guidance in the planning and installation stages, as well as for the implementation of radiation protection for continuing operations. Because of their rapidly growing importance, the problems of installation and radiation safety of standard medical and industrial accelerators are discussed in separate sections. Special discussions are devoted to the radiation protection problems unique to electron accelerators: thick-target bremsstrahlung, the electromagnetic cascade, the estimation of secondary-radiation yields from thick targets, and instrumental corrections for accelerator duty factor. In addition, an extensive review of neutron production is given which includes new calculations of neutron production in various materials. A recalculation of activation in a variety of materials has been done for this manual, and specific gamma-ray constants have been recalculated for a number of nuclides to take into account the contribution of K X-rays. The subjects of air and water activation, as well as toxic gas production in air have been specially reviewed. Betatrons and electron microtrons operating at the same energy produce essentially the same kind of secondary radiation as electron linacs and the material given in this manual is directly applicable to them

  14. Safety managements of the linear IFMIF/EVEDA prototype accelerator

    International Nuclear Information System (INIS)

    Highlights: •Safety management is needed to secure the personnel safety from high dose rate. •The management of access to the accelerator vault is mainly performed by PPS. •The operation management is needed for safety during Injector and RFQ commissioning. •Pulse Duty Management system is newly developed for Injector commissioning for operation management. •PDM system is useful to reduce the radioactivation of equipment and the radiation exposure during and after beam operation. -- Abstract: On the Linear IFMIF/EVEDA Prototype Accelerator (LIPAc), the validation up to 9 MeV deuteron beam with 125 mA continuous wave is planned in Rokkasho, Aomori, Japan. Since the deuteron beam power exceeds 1 MW, safety issue related to γ-ray and neutron production is critical. To establish the safety management indispensable to reduce radiation exposure for personnel and activation of accelerator equipment, Personnel Protection System (PPS) of LIPAc control system, which works together with Radiation Monitoring System and Access Control System, was developed for LIPAc. The management of access to the accelerator vault by PPS and the beam duty management of PPS are presented in details

  15. Construction of the ISTRA-56 proton linear accelerator at ITEP

    International Nuclear Information System (INIS)

    The status of the ISTRA-56 proton linear accelerator construction, which is designed for proton energy of 56 MeV, beam current of 150-200 mA in a pulse of 30 ms duration with the pulse frequency of 1 Hz, is described. Results of preliminary adjustment with drift tube mockup are presented. On the basis of the GI-27A valve the generators for the power of up to 3.5 Mw in a pulse of 180 Ms duration are produced. Computerized system of data acquisition and control is being developed. The ISTRA-56 accelerator is designed as a new injector of protons to the ITEP synchrotron. 8 refs.; 5 figs.; 1 tab

  16. Design of input and output couplers for linear accelerator structures

    International Nuclear Information System (INIS)

    The input and output couplers for 2m-long S-band linear-accelerator structures for the KEKB linac upgrade have been designed and tested. The dimensions of the coupler cavities were estimated by a simulation of the Kyhl method using the MAFIA code, and determined by low-power tests using the Kyhl method. It has been shown that the coupler dimensions can be predicted with precision to be less than 0.5 mm. The asymmetry of the electromagnetic field (amplitude and phase) in the couplers has been corrected by a crescent-shaped cut on the opposite side of the iris. The total performance of the accelerator structures with these couplers is also described. (author)

  17. Daily QA of linear accelerators using only EPID and OBI

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Baozhou, E-mail: bsun@radonc.wustl.edu; Goddu, S. Murty; Yaddanapudi, Sridhar; Noel, Camille; Li, Hua; Cai, Bin; Kavanaugh, James; Mutic, Sasa [Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, Missouri 63110 (United States)

    2015-10-15

    Purpose: As treatment delivery becomes more complex, there is a pressing need for robust quality assurance (QA) tools to improve efficiency and comprehensiveness while simultaneously maintaining high accuracy and sensitivity. This work aims to present the hardware and software tools developed for comprehensive QA of linear accelerator (LINAC) using only electronic portal imaging devices (EPIDs) and kV flat panel detectors. Methods: A daily QA phantom, which includes two orthogonally positioned phantoms for QA of MV-beams and kV onboard imaging (OBI) is suspended from the gantry accessory holder to test both geometric and dosimetric components of a LINAC and an OBI. The MV component consists of a 0.5 cm water-equivalent plastic sheet incorporating 11 circular steel plugs for transmission measurements through multiple thicknesses and one resolution plug for MV-image quality testing. The kV-phantom consists of a Leeds phantom (TOR-18 FG phantom supplied by Varian) for testing low and high contrast resolutions. In the developed process, the existing LINAC tools were used to automate daily acquisition of MV and kV images and software tools were developed for simultaneous analysis of these images. A method was developed to derive and evaluate traditional QA parameters from these images [output, flatness, symmetry, uniformity, TPR{sub 20/10}, and positional accuracy of the jaws and multileaf collimators (MLCs)]. The EPID-based daily QA tools were validated by performing measurements on a detuned 6 MV beam to test its effectiveness in detecting errors in output, symmetry, energy, and MLC positions. The developed QA process was clinically commissioned, implemented, and evaluated on a Varian TrueBeam LINAC (Varian Medical System, Palo Alto, CA) over a period of three months. Results: Machine output constancy measured with an EPID (as compared against a calibrated ion-chamber) is shown to be within ±0.5%. Beam symmetry and flatness deviations measured using an EPID and a 2D

  18. Daily QA of linear accelerators using only EPID and OBI

    International Nuclear Information System (INIS)

    Purpose: As treatment delivery becomes more complex, there is a pressing need for robust quality assurance (QA) tools to improve efficiency and comprehensiveness while simultaneously maintaining high accuracy and sensitivity. This work aims to present the hardware and software tools developed for comprehensive QA of linear accelerator (LINAC) using only electronic portal imaging devices (EPIDs) and kV flat panel detectors. Methods: A daily QA phantom, which includes two orthogonally positioned phantoms for QA of MV-beams and kV onboard imaging (OBI) is suspended from the gantry accessory holder to test both geometric and dosimetric components of a LINAC and an OBI. The MV component consists of a 0.5 cm water-equivalent plastic sheet incorporating 11 circular steel plugs for transmission measurements through multiple thicknesses and one resolution plug for MV-image quality testing. The kV-phantom consists of a Leeds phantom (TOR-18 FG phantom supplied by Varian) for testing low and high contrast resolutions. In the developed process, the existing LINAC tools were used to automate daily acquisition of MV and kV images and software tools were developed for simultaneous analysis of these images. A method was developed to derive and evaluate traditional QA parameters from these images [output, flatness, symmetry, uniformity, TPR20/10, and positional accuracy of the jaws and multileaf collimators (MLCs)]. The EPID-based daily QA tools were validated by performing measurements on a detuned 6 MV beam to test its effectiveness in detecting errors in output, symmetry, energy, and MLC positions. The developed QA process was clinically commissioned, implemented, and evaluated on a Varian TrueBeam LINAC (Varian Medical System, Palo Alto, CA) over a period of three months. Results: Machine output constancy measured with an EPID (as compared against a calibrated ion-chamber) is shown to be within ±0.5%. Beam symmetry and flatness deviations measured using an EPID and a 2D ion

  19. The new control system of the Saclay linear accelerator

    International Nuclear Information System (INIS)

    A new control system for the Safety Linear Accelerator is now being designed. The computer control architecture is based on 3 dedicated VME crates with MC68000 micro-processors: one crate with a disk-based operating system will run the high level application programs and the data base management facilities, another one will manage the man-machine communications and the third one will interface the system to the linac equipments. Communications between the VME microcomputers will be done through 16 bit parallel links. The software is modular and organized in specific layers, the data base is fully distributed. About 90% of the code is written in Fortran

  20. Design of a self-focusing linear electron accelerator

    International Nuclear Information System (INIS)

    In this report we tackle the principal physical and technical problems related to the design of a self-focusing linear electron accelerator. The study of the dynamic phenomena occurring at the entrance to the first resonant cell allows us, by an adequate choice of the longitudinal height of this cell, to avoid the use of an external magnetic focusing coil. Optimization of the ultra high frequency properties of the resonant structure has been achieved by polishing the internal surfaces of the cavities, by adapting a new brazing technique and optimizing the geometry of the cells. A simulation code has been adapted to an interactive use on microcomputer

  1. Examination of sea freight containers using modern electron linear accelerators

    International Nuclear Information System (INIS)

    Electron linear accelerators and scintillation line detectors were studied as major components of a transmission scanning system to check the contents of standard sea containers. A maximum beam energy of 10 MeV was found to be the best compromise of high penetration capability of the bremsstrahlung and the WHO recommendations for irradiation of food. CsI(Tl) scintillation detectors turned out to be very efficient and reliable for this rugged application. The results obtained in full size prototype systems are discussed. (orig.)

  2. Induction linear accelerators for commercial photon irradiation processing

    International Nuclear Information System (INIS)

    A number of proposed irradiation processes requires bulk rather than surface exposure with intense applications of ionizing radiation. Typical examples are irradiation of food packaged into pallet size containers, processing of sewer sludge for recycling as landfill and fertilizer, sterilization of prepackaged medical disposals, treatment of municipal water supplies for pathogen reduction, etc. Volumetric processing of dense, bulky products with ionizing radiation requires high energy photon sources because electrons are not penetrating enough to provide uniform bulk dose deposition in thick, dense samples. Induction Linear Accelerator (ILA) technology developed at the Lawrence Livermore National Laboratory promises to play a key role in providing solutions to this problem. This is discussed in this paper

  3. The challenges of commercial isotope production on a linear accelerator

    International Nuclear Information System (INIS)

    The pulsed beam structure inherent to linear accelerators differentiates it from the characteristic cw nature of cyclotrons. This property can result in additional challenges in isotope production targetry where issues of low melting point, rapid thermal cycling, inadequate cooling designs etc. can have an effect. In contrast, the advantages of multiple simultaneous target stations at several beam energies makes this device especially attractive. It allows for the possibility of economically producing specialized research isotopes in combination with large quantities of established commercial products. The operational history of the Denton LINAC facility will be presented as it relates to those particular challenges of isotope production with a high power LINAC beam

  4. The JHP 200-MeV proton linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Takao [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

    1997-11-01

    A 200-MeV proton linear accelerator for the Japanese Hadron Project (JHP) has been designed. It consists of a 3-MeV radio-frequency quadrupole linac (RFQ), a 50-MeV drift tube linac (DTL) and a 200-MeV separated-type drift tube linac (SDTL). A frequency of 324 MHz has been chosen for all of the rf structures. A peak current of 30 mA (H{sup -} ions) of 400 {mu}sec pulse duration will be accelerated at a repetition rate of 25 Hz. A future upgrade plan up to 400 MeV is also presented, in which annular-coupled structures (ACS) of 972 MHz are used in an energy range of above 150 or 200 MeV. One of the design features is its high performance for a beam-loss problem during acceleration. It can be achieved by separating the transition point in the transverse motion from that of the longitudinal motion. The transverse transition at a rather low-energy range decreases the effects of space-charge, while the longitudinal transition at a rather high-energy range decreases the effects of nonlinear problems related to acceleration in the ACS. Coupled envelope equations and equipartitioning theory are used for the focusing design. The adoption of the SDTL structure improves both the effective shunt impedance and difficulties in fabricating drift tubes with focusing magnets. An accurate beam-simulation code on a parallel supercomputer was used for confirming any beam-loss problem during acceleration. (author)

  5. To study the emittance dilution in Superconducting Linear Accelerator Design for International Linear Collider (ILC)

    Science.gov (United States)

    Ranjan, Kirti; Solyak, Nikolay; Tenenbaum, Peter

    2005-04-01

    Recently the particle physics community has chosen a single technology for the new accelerator, opening the way for the world community to unite and concentrate resources on the design of an International Linear collider (ILC) using superconducting technology. One of the key operational issues in the design of the ILC will be the preservation of the small beam emittances during passage through the main linear accelerator (linac). Sources of emittance dilution include incoherent misalignments of the quadrupole magnets and rf-structure misalignments. In this work, the study of emittance dilution for the 500-GeV center of mass energy main linac of the Superconducting Linear Accelerator design, based on adaptation of the TESLA TDR design is performed using LIAR simulation program. Based on the tolerances of the present design, effect of two important Beam-Based steering algorithms, Flat Steering and Dispersion Free Steering, are compared with respect to the emittance dilution in the main linac. We also investigated the effect of various misalignments on the emittance dilution for these two steering algorithms.

  6. High Precision Survey and Alignment of Large Linear Accelerators

    CERN Document Server

    Prenting, J

    2004-01-01

    For the future linear accelerator TESLA the demanded accuracy for the alignment of the components is 0.5 mm horizontal and 0.2 mm vertical, both on each 600 m section. Other accelerators require similar accuracies. These demands can not be fulfilled with open-air geodetic methods, mainly because of refraction. Therefore the RTRS (Rapid Tunnel Reference Surveyor), a measurement train performing overlapping multipoint alignment on a reference network is being developed. Two refraction-free realizations of this concept are being developed at the moment: the first one (GeLiS) measures the horizontal co-ordinates using stretched wires, combined with photogrammetric split-image sensors in a distance measurement configuration. In areas of the tunnel where the accelerator is following the earth curvature GeLiS measures the height using a new hydrostatic leveling system. The second concept (LiCAS) is based on laser straightness monitors (LSM) combined with frequency scanning interferometry (FSI) in an evacuated system...

  7. RF properties of periodic accelerating structures for linear colliders

    International Nuclear Information System (INIS)

    With the advent of the SLAC electron-positron linear collider (SLC) in the 100 GeV center-of-mass energy range, research and development work on even higher energy machines of this type has started in several laboratories in the United States, Europe, the Soviet Union and Japan. These linear colliders appear to provide the only promising approach to studying e+e- physics at center-of-mass energies approaching 1 TeV. This thesis concerns itself with the study of radio frequency properties of periodic accelerating structures for linear colliders and their interaction with bunched beams. The topics that have been investigated are: experimental measurements of the energy loss of single bunches to longitudinal modes in two types of structures, using an equivalent signal on a coaxial wire to simulate the beam; a method of canceling the energy spread created within a single bunch by longitudinal wakefields, through appropriate shaping of the longitudinal charge distribution of the bunch; derivation of the complete transient beam-loading equation for a train of bunches passing through a constant-gradient accelerator section, with application to the calculation and minimization of multi-bunch energy spread; detailed study of field emission and radio frequency breakdown in disk-loaded structures at S-, C- and X-band frequencies under extremely high-gradient conditions, with special attention to thermal effects, radiation, sparking, emission of gases, surface damage through explosive emission and its possible control through RF-gas processing. 53 refs., 49 figs., 9 tabs

  8. Towards MRI-guided linear accelerator control: gating on an MRI accelerator

    International Nuclear Information System (INIS)

    To boost the possibilities of image guidance in radiotherapy by providing images with superior soft-tissue contrast during treatment, we pursue diagnostic quality MRI functionality integrated with a linear accelerator. Large respiration-induced semi-periodic target excursions hamper treatment of cancer of the abdominal organs. Methods to compensate in real time for such motion are gating and tracking. These strategies are most effective in cases where anatomic motion can be visualized directly, which supports the use of an integrated MRI accelerator. We establish here an infrastructure needed to realize gated radiation delivery based on MR feedback and demonstrate its potential as a first step towards more advanced image guidance techniques. The position of a phantom subjected to one-dimensional periodic translation is tracked with the MR scanner. Real-time communication with the MR scanner and control of the radiation beam are established. Based on the time-resolved position of the phantom, gated radiation delivery to the phantom is realized. Dose distributions for dynamic delivery conditions with varying gating windows are recorded on gafchromic film. The similarity between dynamically and statically obtained dose profiles gradually increases as the gating window is decreased. With gating windows of 5 mm, we obtain sharp dose profiles. We validate our gating implementation by comparing measured dose profiles to theoretical profiles calculated using the knowledge of the imposed motion pattern. Excellent correspondence is observed. At the same time, we show that real-time on-line reconstruction of the accumulated dose can be performed using time-resolved target position information. This facilitates plan adaptation not only on a fraction-to-fraction scale but also during one fraction, which is especially valuable in highly accelerated treatment strategies. With the currently established framework and upcoming improvements to our prototype-integrated MRI accelerator

  9. Reducing the asymmetry in coupled cavity of linear accelerator

    International Nuclear Information System (INIS)

    Background: With the development of high energy physics, high performance of electron linear accelerator is required for large collider, FEL and high brightness synchrotron radiation light source. Structure asymmetry of single coupler destroys the symmetry of field distribution in coupled cavity, which reduces the quality of beam. Purpose: Optimize the asymmetry of field distribution in coupled cavity and improve the quality of beam. Methods: The simulation designs are made for single offset coupler, double symmetry coupler and the new coupler loaded by dielectric rods at X band by using CST microwave studio code. Results: The results show that the distribution of field in coupled cavity is better and all particles almost locate at the center of beam hole after beam passing through the coupler loaded by dielectric rods. The energy spread has also been significantly improved. Conclusions: The coupler loaded by dielectric rods can optimize the asymmetry of field distribution in coupled cavity and improve the quality of beam. (authors)

  10. On measuring charged particle bunch duration in linear accelerators

    International Nuclear Information System (INIS)

    The process of measuring short bunches is simulated by means of cavity resonators in which HF fields are excited by both positive and negative ion bunches flying through them. The simulation is aimed to assess optimum operation of a linear accelerator. A set of bunches of chance form and duration is simulated. Then the simulation of the process of restoring the duration and shape of a bunch according to data obtained from a limited number of resonators is realized. The use of 3-4 resonators tuned to 3, 6, 9 and 12-th harmonics of bunch repetition rate is shown to be sufficient for determining bunch duration with an accuracy of several per cent. When data on harmonic phases is available, one can obtain information on beam asymmetry

  11. Longitudinal jitter analysis of linear accelerator electron gun

    CERN Document Server

    Mingshan, Liu; Iqbal, Munawar

    2015-01-01

    We present measurement and analyses of longitudinal timing jitter of Beijing Electron Positron Collider (BEPCII) linear accelerator electron gun. We simulated longitudinal jitter effect of the gun using PARMELA about beam performance including beam profile, average energy, energy spread, longitudinal phase of reference particle and XY emittance. The maximum percentage difference of the beam parameters are calculated to be; 100%, 13.27%, 42.24%, 7.79% and 65.01%, 86.81%, respectively due to which the bunching efficiency is reduced to 54%. The simulation results are in agreement with test and are helpful to optimize the beam parameters by tuning the trigger timing of the gun during the bunching process.

  12. Accelerating transient simulation of linear reduced order models.

    Energy Technology Data Exchange (ETDEWEB)

    Thornquist, Heidi K.; Mei, Ting; Keiter, Eric Richard; Bond, Brad

    2011-10-01

    Model order reduction (MOR) techniques have been used to facilitate the analysis of dynamical systems for many years. Although existing model reduction techniques are capable of providing huge speedups in the frequency domain analysis (i.e. AC response) of linear systems, such speedups are often not obtained when performing transient analysis on the systems, particularly when coupled with other circuit components. Reduced system size, which is the ostensible goal of MOR methods, is often insufficient to improve transient simulation speed on realistic circuit problems. It can be shown that making the correct reduced order model (ROM) implementation choices is crucial to the practical application of MOR methods. In this report we investigate methods for accelerating the simulation of circuits containing ROM blocks using the circuit simulator Xyce.

  13. Terahertz radiation source using an industrial electron linear accelerator

    CERN Document Server

    Kalkal, Yashvir

    2015-01-01

    High power ($\\sim 100$ kW) industrial electron linear accelerators (linacs) are used for irradiation applications e.g., for pasteurization of food products, disinfection of medical waste, etc. We propose that high power electron beam from such an industrial linac can be first passed through an undulator to generate powerful terahertz (THz) radiation, and the spent electron beam coming out of the undulator can still be used for industrial applications. This will enhance the utilisation of a high power industrial linac. We have performed calculation of spontaneous emission in the undulator to show that for typical parameters, continuous terahertz radiation having power of the order of $\\mu$W can be produced, which may be useful for many scientific applications.

  14. Linear Fixed-Field Multi-Pass Arcs for Recirculating Linear Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    V.S. Morozov, S.A. Bogacz, Y.R. Roblin, K.B. Beard

    2012-06-01

    Recirculating Linear Accelerators (RLA's) provide a compact and efficient way of accelerating particle beams to medium and high energies by reusing the same linac for multiple passes. In the conventional scheme, after each pass, the different energy beams coming out of the linac are separated and directed into appropriate arcs for recirculation, with each pass requiring a separate fixed-energy arc. In this paper we present a concept of an RLA return arc based on linear combined-function magnets, in which two and potentially more consecutive passes with very different energies are transported through the same string of magnets. By adjusting the dipole and quadrupole components of the constituting linear combined-function magnets, the arc is designed to be achromatic and to have zero initial and final reference orbit offsets for all transported beam energies. We demonstrate the concept by developing a design for a droplet-shaped return arc for a dog-bone RLA capable of transporting two beam passes with momenta different by a factor of two. We present the results of tracking simulations of the two passes and lay out the path to end-to-end design and simulation of a complete dog-bone RLA.

  15. Development status of 200 KeV, linear induction accelerator

    International Nuclear Information System (INIS)

    Full text: The Linear Induction Accelerator is being constructed for research and applications of high energy beams with high repetition rate. This paper presents the status of 200 keV, 5 kA, 50 ns, 10 Hz-100 Hz Linear Induction Accelerator (LIA) project undertaken by us. The main challenges involved in this project are development of (i) high power switching modules, (ii) pulse transformer with minimal leakage inductance and (iii) magnetic switches iv) induction cavities. Our scheme starts with a low voltage high current DC system charging a capacitor followed by a chain of compression stages and voltage step-up. The 2.5kV : 20kV first stage pulse transformer with built-in reset arrangement has been designed and fabricated with 6-toroidal amorphous cores of size 160/240/25mm. The total leakage inductance could be minimized to 3.5mH. The coaxially designed next stage pulse compression module has been fabricated and tested for full ratings. Water capacitors have been designed for energy storage at subsequent microsecond time scales. Provided with demineralised water circulation and adequate mechanical support, they are currently under fabrication. A 2.5 W water pulse- forming line (PFL) with water-oil interface is also designed to realize a pulse of 50 ns duration across a matched load with minimum distortion. The PFL is connected to the three induction cavities in parallel by a single output switch and three parallel bunches of cable with 100 kV insulation ratings providing an effective characteristic impedance of 2.5 W. Prototype induction cavities using amorphous cores at 20 kV voltage level have been operated in the adder mode. The graphite field emission diode is connected at the output of the adder consisting of three 75 kV induction modules offering a reflected impedance which matches with that of the PFL

  16. Development of the diagrams of diagnosis of bread linear accelerator

    International Nuclear Information System (INIS)

    The radiotherapy indicates the whole techniques of irradiation to therapeutic, aiming on the biological effects of the direct radiations or indirectly ionizing (photons electrons, neutrons, protons) to destroy the cancerous tumours. The radiotherapy intervene alone or in partnership with other techniques such as: surgery, chemotherapy, therapeutic laser. In Tunisia and at the Institute of Salah Azeiz, the service of radiotherapy is equipped with an electron linear accelerator and sight its effectiveness remarkable for the treatment of cancer, we will study in this project, the principle operation of this system, its composition and we will try to carry out diagrams of diagnosis for some demolished which appear in one of the apparatus system. Indeed, we will simulate the defect on the machine to lead to a digraph of checked diagnosis. These diagrams of diagnosis can guide the reflexion of the agent of maintenance while following a logical advance is structured. This project was an enriching contribution on the theoretical and practical level. On the theoretical level: - To look further into and improve our theoretical knowledge on the accelerator. - to familiarize itself with the hospital medium. - To acquire an experiment in the field of repair of the medical apparatuses. - To establish the diagrams of diagnosis of the breakdowns. Thus, we wish that this work carried out will be a significant support for others, and will be finished and computerized. Computerized diagrams of diagnosis will constitute a considerable working tool for the technicians and the engineers of maintenance. (author). 13 refs

  17. Engineering progress of the linear IFMIF prototype accelerator (LIPAc)

    International Nuclear Information System (INIS)

    The linear IFMIF prototype accelerator (LIPAc) has been launched within the framework of the Broader Approach Agreement with the objective to validate the low energy part (9 MeV) for the IFMIF linacs (40 MeV, 125 mA of D+ beam in continuous wave). Starting in mid-2007, the project is managed by the two Home Teams (JA-HT and EU-HT) and headed by the Project Team at the Broader Approach site in Rokkasho with the aim to complete the validation activity with the installation and commissioning of the whole LIPAc by June 2017. Following a short description and current status of each accelerator component, this paper describes the integration activities such as the 3D mockup integration and the Interface Management System (IMS) tools developed for use at the Integrated Project Team level. In preparation of the first equipment delivery in Japan at the beginning of 2013, implementation and installation activities of the various components are described, in particular assembly procedures associated with each subsystem

  18. Tiger Team Assessment of the Stanford Linear Accelerator Center

    International Nuclear Information System (INIS)

    This report documents the Tiger Team Assessment of the buildings, facilities, and activities at the Stanford Linear Accelerator Center (SLAC) and the Stanford Synchrotron Radiation Laboratory (SSRL) near San Francisco, California. SLAC/SSRL is the twenty-eighth DOE site to be assessed by a Tiger Team. SLAC and SSRL are single-purpose laboratories. SLAC is dedicated to experimental and theoretical research in elementary particle physics and to the development of new techniques in high-energy accelerators and elementary particle detectors. SSRL is dedicated to research in atomic and solid-state physics, chemistry, biology, and medicine. The purpose of the SLAC/SSRL Tiger Team Assessment is to provide the Secretary of Energy with concise information on the following: current ES ampersand H compliance status at the site and the vulnerabilities associated with that compliance status; root causes for noncompliance; adequacy of DOE and SLAC/SSRL ES ampersand H management programs; response actions to address identified problem areas; and effectiveness of self-assessment

  19. Design of time control system of high current proton linear accelerator

    International Nuclear Information System (INIS)

    The high current proton linear accelerator with high duty ratio will be used in accelerator driven sub-critical system. Time control system of high current proton linear accelerator is introduced. During accelerator operation, the system provides necessary trigger and clock signal. Accuracy and stability of the system has important implications for operation of the linear accelerator. Design of serial communication hardware based on ALTERA company cyclone Ⅲ FPGA, programming of serial communication drivers and functional modules, and implement of human-computer interface based on LabVIEW are realized. The testing results show that the whole system meets requirements of time control system of the high current proton accelerator. (authors)

  20. HOM-Free Linear Accelerating Structure for e+ e- Linear Collider at C-Band

    CERN Document Server

    Kubo, K

    2003-01-01

    HOM-free linear acceleration structure using the choke mode cavity (damped cavity) is now under design for e sup + e sup - linear collider project at C-band frequency (5712 MHz). Since this structure shows powerful damping effect on most of all HOMs, there is no multibunch problem due to long range wakefields. The structure will be equipped with the microwave absorbers in each cells and also the in-line dummy load in the last few cells. The straightness tolerance for 1.8 m long structure is closer than 30 (micro)m for 25% emittance dilution limit, which can be achieved by standard machining and braising techniques. Since it has good vacuum pumping conductance through annular gaps in each cell, instabilities due to the interaction of beam with the residual-gas and ions can be minimized.

  1. Angular and linear accelerations of a rolling cylinder acted by an external force

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, V, E-mail: voliveira@isel.ipl.pt [Instituto Superior Engenharia de Lisboa, Avenida Conselheiro Emidio Navarro no 1, 1959-007 Lisboa (Portugal)

    2011-03-15

    The dynamics of a cylinder rolling on a horizontal plane acted on by an external force applied at an arbitrary angle is studied with emphasis on the directions of the acceleration of the centre-of-mass and the angular acceleration of the body. If rolling occurs without slipping, there is a relationship between the directions of these accelerations. If the linear acceleration points to the right, then the angular acceleration is clockwise. On the other hand, if it points to the left, then the angular acceleration is counterclockwise. In contrast, if rolling and slipping occurs, the direction of the linear acceleration does not determine the direction of the angular acceleration. For example, the linear acceleration may point to the right and the angular acceleration clockwise or counterclockwise depending on the external force orientation and point of application.

  2. Commissioning and early experience with a new-generation low-energy linear accelerator with advanced delivery and imaging functionalities

    OpenAIRE

    Fogliata Antonella; Vanetti Eugenio; Nicolini Giorgia; Clivio Alessandro; Cozzi Luca

    2011-01-01

    Abstract Background A new-generation low-energy linear accelerator (UNIQUE) was introduced in the clinical arena during 2009 by Varian Medical Systems. The world's first UNIQUE was installed at Oncology Institute of Southern Switzerland and put into clinical operation in June 2010. The aim of the present contribution was to report experience about its commissioning and first year results from clinical operation. Methods Commissioning data, beam characteristics and the modeling into the treatm...

  3. Monte Carlo simulation of medical linear accelerator using primo code

    International Nuclear Information System (INIS)

    The use of monte Carlo simulation has become very important in the medical field and especially in calculation in radiotherapy. Various Monte Carlo codes were developed simulating interactions of particles and photons with matter. One of these codes is PRIMO that performs simulation of radiation transport from the primary electron source of a linac to estimate the absorbed dose in a water phantom or computerized tomography (CT). PRIMO is based on Penelope Monte Carlo code. Measurements of 6 MV photon beam PDD and profile were done for Elekta precise linear accelerator at Radiation and Isotopes Center Khartoum using computerized Blue water phantom and CC13 Ionization Chamber. accept Software was used to control the phantom to measure and verify dose distribution. Elektalinac from the list of available linacs in PRIMO was tuned to model Elekta precise linear accelerator. Beam parameter of 6.0 MeV initial electron energy, 0.20 MeV FWHM, and 0.20 cm focal spot FWHM were used, and an error of 4% between calculated and measured curves was found. The buildup region Z max was 1.40 cm and homogenous profile in cross line and in line were acquired. A number of studies were done to verily the model usability one of them is the effect of the number of histories on accuracy of the simulation and the resulted profile for the same beam parameters. The effect was noticeable and inaccuracies in the profile were reduced by increasing the number of histories. Another study was the effect of Side-step errors on the calculated dose which was compared with the measured dose for the same setting.It was in range of 2% for 5 cm shift, but it was higher in the calculated dose because of the small difference between the tuned model and measured dose curves. Future developments include simulating asymmetrical fields, calculating the dose distribution in computerized tomographic (CT) volume, studying the effect of beam modifiers on beam profile for both electron and photon beams.(Author)

  4. Environmental Management Assessment of the Stanford Linear Accelerator Center

    International Nuclear Information System (INIS)

    This report documents the results of the Environmental Management Assessment of the Stanford Linear Accelerator Center (SLAC), Menlo Park, California. During this assessment, the activities conducted by the assessment team included reviews of internal documents and reports from previous assessments; interviews with the US Department of Energy (DOE), US Environmental Protection Agency, State Water Resources Board, California Regional Water Quality Control Board, and SLAC contractor personnel; and inspections and observations of selected facilities and operations. Onsite portion of the assessment was conducted from January 18 through January 31, 1994, by the DOE Office of Environmental Audit (EH-24), located within the Office of Environment, Safety and Health (EH), and the Environment and Safety Support Division (ESS), located within the Oakland Operations Office (OAK). The EH-24 environmental management assessment and the OAK functional appraisal were combined to minimize disruptions to the site. The management disciplines and three technical areas (air quality, groundwater, and inactive waste sites) were evaluated by EH-24, and four other technical areas (surface water, waste management, toxic and chemical materials, and environmental radiation) were assessed by ESS

  5. Portal film charts for a 6 MV linear accelerator

    International Nuclear Information System (INIS)

    Localization errors frequently arise in the portal film technique due to over-or underdevelop films, for high energy radiotherapy machines. To guarantee the accuracy and reproducibility of the localization film technique portal film charts were introduced into the routine planning for the Mevatron 6MV linear accelerator of the Beilinson Radiotherapy Dept. Maintaining reproducible film processor conditions, two films were used: medical X-ray film Curix RPI Agfa and localization film X-OMAT TL Kodak, combined with front and rear copper screens of 0.5 mm thickness each. The sensitometric curves for each film-screen combination were obtained (optical density as function of cassette dose). The least square fitted O.D. curve was used to obtain the cassette dose which produces an O.D. of 1.6. A theoretical equation for the calculation of the dose at the cassette positions, beyond a water phantom, as function of field size, SSD, patient thickness and patient to cassette separation, was experimentally checked with a 0.6 cc Farmer ionization chamber coupled to a 2570 Farmer dosimeter. As a result portal film charts (expressed in MU) were constructed as a function of FS, air-gap and patient-thickness, and the best partition dose for the double-exposure technique was also established. The patients dose in the double exposure technique was compared to that delivered in diagnostic radiology procedures. (author)

  6. The LLNL Flash X-Ray Induction Linear Accelerator (FXR)

    Energy Technology Data Exchange (ETDEWEB)

    Multhauf, L G

    2002-09-19

    The FXR is an induction linear accelerator used for high-speed radiography at the Lawrence Livermore National Laboratory's Experimental Test Site. It was designed specifically for the radiography of very thick explosive objects. Since its completion in 1982, it has been very actively used for a large variety of explosives tests, and has been periodically upgraded to achieve higher performance. Upgrades have addressed machine reliability, radiographic sensitivity and resolution, two-frame imaging by double pulsing improvements that are described in detail in the paper. At the same time, the facility in which it was installed has also been extensively upgraded, first by adding space for optical and interferometric diagnostics, and more recently by adding a containment chamber to prevent the environmental dispersal of hazardous and radioactive materials. The containment addition also further expands space for new non-radiographic diagnostics. The new Contained Firing Facility is still in the process of activation. At the same time, FXR is continuing to undergo modifications aimed primarily at further increasing radiographic resolution and sensitivity, and at improving double-pulsed performance.

  7. Multipurpose 5-MeV linear induction accelerator

    International Nuclear Information System (INIS)

    Although linear induction accelerators (LIAs) are quite reliable by most standards, they are limited in repeating rate, average power, and reliability because the final stage of energy delivery is based on spark gap performance. In addition, they have a low duty factor of operation. To provide a higher burst rate and greater reliability, the researchers used new technology to develop a magnetic pulse compression scheme that eliminates all spark gaps and exceeds requirements. The paper describes the scheme. The magnetic drive system can be tailored to drive induction cells from a few kA to over 10 kA at 500 kV, with average beam power levels in the megawatts. This new 5-MeV, 2.5-kA LIA under construction at the Lawrence Livermore National Laboratory (LLNL) will be used for the development of high brightness sources and will provide a test bed for the new technology, which should lead to LIAs that surpass the radio frequency linacs for efficiency and reliability, as well as fit other industrial applications, such as sewage sterilization

  8. Multipurpose 5-MeV linear induction accelerator

    Science.gov (United States)

    Birx, D. L.; Hawkins, S. A.; Poor, S. E.; Reginato, L. L.; Smith, M. W.

    1984-06-01

    Although linear induction accelerators (LIAs) are quite reliable by most standards, they are limited in repeating rate, average power, and reliability because the final stage of energy delivery is based on spark gap performance. In addition, they have a low duty factor of operation. To provide a higher burst rate and greater reliability, new technology was used to develop a magnetic pulse compression scheme that eliminates all spark gaps and exceeds requirements. The magnetic drive system are tailored to drive induction cells from a few kA to over 10 kA at 500 kV, with average beam power levels in the megawatts. This new 5-MeV, 2.5-kA LIA under construction at the Lawrence Livermore National Laboratory (LLNL) will be used for the development of high brightness sources and will provide a test bed for the new technology, which should lead to LIAs that surpass the radio frequency linacs for efficiency and reliability, as well as fit other industrial applications, such as sewage sterilization.

  9. Quality assurance protocol for linear accelerators used in radiotherapy

    International Nuclear Information System (INIS)

    Radiotherapy is a modality of choice for treatment of malignant diseases. Linear accelerators are the most common devices for implementing external radiation therapy. Taking into account the fact during the treatment, healthy tissue will inevitably be exposed to ionizing radiation, predicted dose in each radiotherapy case should be delivered with the greatest possible accuracy. Medical requirement for quality treatment achieving means as mach as possible dose into volume of interest and the greatest possible healthy tissue protection. From radiation protection point of view, occupational exposure of the staff involved in radiotherapy process should be minimized. To be able to reach it, consistent adherence to the Quality Assurance Programme is necessary. It should be in accordance with higher national and international protocols, because they give guidelines on the necessary standards, procedures, processes, resources and responsibilities that should be defined in structuring the overall radiotherapy quality management. As a part of this Master thesis, quality management as well as Quality Assurance Programme that is necessary to be applied in each radiotherapy center have been prepared. Mandatory dosimetry measurements included in the internal recommendations are also emphasized. Measurement results and external audit by IAEA indicated high accuracy and quality radiotherapy dose delivering in Macedonia. Based on the measurements and analysis, the aim of this Master thesis is offering a Quality Assurance Protocol for external beam radiotherapy that can be used on the national level in Republic of Macedonia. (Author)

  10. Environmental Survey preliminary report, Stanford Linear Accelerator Center, Stanford, California

    Energy Technology Data Exchange (ETDEWEB)

    1988-07-01

    This report presents the preliminary findings from the first phase of the Survey of the US Department of Energy (DOE) Stanford Linear Accelerator Center (SLAC) at Stanford, California, conducted February 29 through March 4, 1988. The Survey is being conducted by an interdisciplinary team of environmental specialists, led and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. Individual team components are being supplied by a private contractor. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with the SLAC. The Survey covers all environmental media and all areas of environmental regulation and is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations at the SLAC, and interviews with site personnel. The Survey team is developing a Sampling and Analysis Plan to assist in further assessing certain of the environmental problems identified during its on-site activities. The Sampling and Analysis Plan will be executed by a DOE National Laboratory or a support contractor. When completed, the results will be incorporated into the Environmental Survey Interim Report for the SLAC facility. The Interim Report will reflect the final determinations of the SLAC Survey. 95 refs., 25 figs., 25 tabs.

  11. Environmental Survey preliminary report, Stanford Linear Accelerator Center, Stanford, California

    International Nuclear Information System (INIS)

    This report presents the preliminary findings from the first phase of the Survey of the US Department of Energy (DOE) Stanford Linear Accelerator Center (SLAC) at Stanford, California, conducted February 29 through March 4, 1988. The Survey is being conducted by an interdisciplinary team of environmental specialists, led and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. Individual team components are being supplied by a private contractor. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with the SLAC. The Survey covers all environmental media and all areas of environmental regulation and is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations at the SLAC, and interviews with site personnel. The Survey team is developing a Sampling and Analysis Plan to assist in further assessing certain of the environmental problems identified during its on-site activities. The Sampling and Analysis Plan will be executed by a DOE National Laboratory or a support contractor. When completed, the results will be incorporated into the Environmental Survey Interim Report for the SLAC facility. The Interim Report will reflect the final determinations of the SLAC Survey. 95 refs., 25 figs., 25 tabs

  12. The application of a linear electron accelerator in radiation processing

    Science.gov (United States)

    Ruiying, Zhou; Binglin, Wang; Wenxiu, Chen; Yongbao, Gu; Yinfen, Zhang; Simin, Qian; Andong, Liu; Peide, Wang

    A 3-5 MeV electron beam generated by a BF-5 type linear electron accelerator has been used in some radiation processing works, such as, (1) The cross-linking technology by radiation for the polyethylene foaming processing --- the correlation between the cross-linkage and the absorbed dose, the relation between the elongation of foaming polyethylene and the dose, the relation between the size of the cavities and the gelatin rate and the optimum range of dosage for foaming have been found. (2) The research work on the fast switch thyristor irradiated by electron beam --- The relation between the absorbed dose and the life-time of minority carriers has been studied and the optimum condition for radiation processing was determined. This process is much better than the conventional gold diffusion in raising the quality and end-product rate of these devices. Besides, we have made some testing works on the hereditary mutation of plant seeds and microorganism mutation induced by electron radiation and radiation sterilization for some medical instruments and foods.

  13. Acquiring beam data for a flattening-filter free linear accelerator using organic scintillators

    DEFF Research Database (Denmark)

    Beierholm, Anders Ravnsborg; Behrens, C.F.; Hoffmann, L.;

    2013-01-01

    -resolved dosimetry on a highly detailed level. In this study, we present beam data for a Varian TrueBeam linear accelerator, which is capable of delivering flattening-filter free (FFF1) clinical X-ray beams. The beam data have been acquired using an in-house developed dosimetry system based on fibre-coupled organic...... scintillators. The presented data exhibit high accuracy and precision when compared with data obtained using commercial dosimetry methods, and agree well with results published in the literature....

  14. Radiosurgery with a linear accelerator in cerebral arteriovenous malformations Radiocirurgia com acelerador linear em malformações arteriovenosas cerebrais

    OpenAIRE

    Sérgio Carlos Barros Esteves; Wladimir Nadalin; Ronie Leo Piske; Salomon Benabou; Evandro de Souza MD; Antonio Carlos Zuliani de Oliveira

    2008-01-01

    OBJECTIVE: To evaluate results achieved with radiosurgery and complications of the procedure when treating arteriovenous malformations with linear accelerator. METHODS: This retrospective study was conducted between October 1993 and December 1996. Sixty-one patients with arteriovenous malformations were treated with radiosurgery utilizing a 6MV energy linear accelerator. Ages of the 32 female and 29 male patients ranged from 6 to 54 years (mean: 28.3 years). The most frequent initial symptom ...

  15. Radiation doses inside industrial irradiation installation with linear electron accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Alexandre R., E-mail: alexandre.lima@cnen.gov.br [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil); Pelegrineli, Samuel Q.; Alo, Gabriel F., E-mail: samuelfisica@yahoo.com.br, E-mail: gabriel.alo@aceletron.com.br [Aceletron Irradiacao Industrial, Aceletrica Comercio e Representacoes Ltda, Rio de Janeiro, RJ (Brazil); Silva, Francisco C.A. Da, E-mail: dasilva@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    Aceletron Industrial Irradiation Company is the unique installation in South America to provide industrial irradiation service using two linear electron accelerators of 18 kW and 10 MeV energy. The electron beam technology allows using electrons to irradiate many goods and materials, such as hospital and medical equipment, cosmetics, herbal products, polymers, peat, gemstones and food. Aceletron Company uses a concrete bunker with 3.66 m of thickness to provide the necessary occupational and environmental radiation protection of X-rays produced. The bunker is divided in main four areas: irradiation room, maze, tower and pit. Inside the irradiation room the x-rays radiation rates are measured in two ways: direct beam and 90 deg C. The rates produced in the conveyor system using 10 MeV energy are 500 Gy/min/mA and 15 Gy/min/mA, respectively. For a 1.8 mA current, the rates produced are 900 Gy/min and 27 Gy/min, respectively. Outside the bunker the radiation rate is at background level, but in the tower door and modulation room the radiation rate is 10 μSv/h. In 2014, during a routine operation, an effective dose of 30.90 mSv was recorded in a monthly individual dosimeter. After the investigation, it was concluded that the dose was only in the dosimeter because it felt inside the irradiation room. As Aceletron Company follows the principles of safety culture, it was decided to perform the radiation isodose curves, inside the four areas of the installation, to know exactly the hotspots positions, exposure times and radiation doses. Five hotspots were chosen taking into account worker's routes and possible operational places. The first experiment was done using a package with three TLD and OSLD dosimeters to obtain better statistical results. The first results for the five hotspots near the accelerator machine showed that the radiation dose rates were between 26 Gy/h and 31 Gy/h. The final measurements were performed using a package with one TLD and one OSLD

  16. Tuning the DARHT Axis-II linear induction accelerator focusing

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Carl A. [Los Alamos National Laboratory

    2012-04-24

    Flash radiography of large hydrodynamic experiments driven by high explosives is a well-known diagnostic technique in use at many laboratories, and the Dual-Axis Radiography for Hydrodynamic Testing (DARHT) facility at Los Alamos produces flash radiographs of large hydrodynamic experiments. Two linear induction accelerators (LIAs) make the bremsstrahlung radiographic source spots for orthogonal views of each test. The 2-kA, 20-MeV Axis-I LIA creates a single 60-ns radiography pulse. The 1.7-kA, 16.5-MeV Axis-II LIA creates up to four radiography pulses by kicking them out of a longer pulse that has a 1.6-{mu}s flattop. The Axis-II injector, LIA, kicker, and downstream transport (DST) to the bremsstrahlung converter are described. Adjusting the magnetic focusing and steering elements to optimize the electron-beam transport through an LIA is often called 'tuning.' As in all high-current LIAs, the focusing field is designed to be as close to that of the ideal continuous solenoid as physically possible. In ideal continuous solenoidal transport a smoothly varying beam size can easily be found for which radial forces balance, and the beam is said to be 'matched' to the focusing field. A 'mismatched' beam exhibits unwanted oscillations in size, which are a source of free energy that contributes to emittance growth. This is undesirable, because in the absence of beam-target effects, the radiographic spot size is proportional to the emittance. Tuning the Axis-II LIA is done in two steps. First, the solenoidal focusing elements are set to values designed to provide a matched beam with little or no envelope oscillations, and little or no beam-breakup (BBU) instability growth. Then, steering elements are adjusted to minimize the motion of the centroid of a well-centered beam at the LIA exit. This article only describes the design of the tune for the focusing solenoids. The DARHT Axis-II LIA was required to be re-tuned after installing an

  17. Method for validating radiobiological samples using a linear accelerator

    International Nuclear Information System (INIS)

    There is an immediate need for rapid triage of the population in case of a large scale exposure to ionizing radiation. Knowing the dose absorbed by the body will allow clinicians to administer medical treatment for the best chance of recovery for the victim. In addition, today's radiotherapy treatment could benefit from additional information regarding the patient's sensitivity to radiation before starting the treatment. As of today, there is no system in place to respond to this demand. This paper will describe specific procedures to mimic the effects of human exposure to ionizing radiation creating the tools for optimization of administered radiation dosimetry for radiotherapy and/or to estimate the doses of radiation received accidentally during a radiation event that could pose a danger to the public. In order to obtain irradiated biological samples to study ionizing radiation absorbed by the body, we performed ex-vivo irradiation of human blood samples using the linear accelerator (LINAC). The LINAC was implemented and calibrated for irradiating human whole blood samples. To test the calibration, a 2 Gy test run was successfully performed on a tube filled with water with an accuracy of 3% in dose distribution. To validate our technique the blood samples were ex-vivo irradiated and the results were analyzed using a gene expression assay to follow the effect of the ionizing irradiation by characterizing dose responsive biomarkers from radiobiological assays. The response of 5 genes was monitored resulting in expression increase with the dose of radiation received. The blood samples treated with the LINAC can provide effective irradiated blood samples suitable for molecular profiling to validate radiobiological measurements via the gene-expression based biodosimetry tools. (orig.)

  18. Monte Carlo simulation of 6 MV medical electron linear accelerator

    International Nuclear Information System (INIS)

    Objective: To analyze the influence of the mean energy and the full-width of half maximum (FWHM) of incident electron beam intensity distribution(assumed Gaussian distribution) on depth dose curves and off-axis ratios and to derive a most optimal combination of mean energy and FWHM of incident electron beam intensity distribution. Methods: The study simulated 6 MV photon beam produced by Varian 600C medical linear accelerator with OMEGA/EGSnrc by matching the relative error of calculated and measured depth dose curves past depth of maximum dose and off-axis ratios at a depth of 10.0 cm in water within 2%. Results: The depth dose curves were relatively insensitive to the mean energy past depth of maximum dose and the FWHM of the incident electron beam intensity distribution. Dose profiles were sensitive to the mean energy and FWHM. The dose profiles horns decreased as the mean energy and the FWHM of the incident electron beam intensity distribution increased. The calculated value of the depth dose curves matched well with the measured value. The calculated value of the off-axis ratio was consistent with the measured value within the radiation field. However, the maximum errors of individual measurement points in the penumbra region and out of the field reached 18.5%. Conclusions: In the field, the most optimal combination of mean energy and FWHM of incident electron beam intensity distribution Can be derived, however, can not be derived out of the field and in the penumbra region. (authors)

  19. Dosimetric comparison of linear accelerator-based stereotactic radiosurgery systems

    Directory of Open Access Journals (Sweden)

    Sharma S

    2007-01-01

    Full Text Available Stereotactic radiosurgery (SRS is a special radiotherapy technique used to irradiate intracranial lesions by 3-D arrangements of narrow photon beams eliminating the needs of invasive surgery. Three different tertiary collimators, namely BrainLab and Radionics circular cones and BrainLab micro multileaf collimator (mMLC, are used for linear accelerator-based SRS systems (X-Knife. Output factor (St, tissue maximum ratio (TMR and off axis ratio (OAR of these three SRS systems were measured using CC01 (Scanditronix/ Welhofer and Pinpoint (PTW cylindrical and Markus plane parallel ionization chambers as well as TLD and radiochromic film. Measurement results of CC01 and Pinpoint chambers were very close to each other which indicate that further reduction in volume and physical dimensions of cylindrical ionization chamber is not necessary for SRS/SRT dosimetry. Output factors of BrainLab and Radionics SRS cones were very close to each other while output factors of equivalent diameter mMLC field were different from SRS circular cones. TMR of the three SRS systems compared were very close to one another. OAR of Radionics cone and BrainLab mMLC were very close to each other, within 2%. However, OARs of BrainLab cone were found comparable to OARs of Radionics cone and BrainLab mMLC within maximum variation of 4%. In addition, user-measured similar data of other three mMLC X-Knives were compared with the mMLC X-Knife data measured in this work and found comparable. The concept of switching over to mMLC-based SRS/SRT is thus validated from dosimetric characteristics as well.

  20. Dosimetric comparison of linear accelerator-based stereotactic radiosurgery systems

    International Nuclear Information System (INIS)

    Stereotactic radiosurgery (SRS) is a special radiotherapy technique used to irradiate intracranial lesions by 3-D arrangements of narrow photon beams eliminating the needs of invasive surgery. Three different tertiary collimators, namely BrainLab and Radionics circular cones and BrainLab micro multileaf collimator (mMLC), are used for linear accelerator-based SRS systems were measured using CC01 (Scanditronix/Welhofer) and Pinpoint (PTW) cylindrical and Markus plane parallel ionization chambers as well as TLD and radiochromic film. Measurement results of CC01 and Pinpoint chambers were very close to each other which indicate that further reduction in volume and physical dimensions of cylindrical ionization chamber is not necessary for SRS/SRT dosimetry. Output factors of BrainLab and Radionics SRS cones were very close to each other while output factors of equivalent diameter mMLC field were different from SRS circular cones. TMR of the three SRS systems compared were very close to one another. OAR of Radionics cone and BrainLab mMLC were very close to each other, within 2%. However, OARs of BrainLab cone were found comparable to OARs of Radionics cone and BrainLab mMLC within maximum variation of 4%. In addition, user-measured similar data of other three mMLC X-Knives were compared with the mMLC X-Knife data measured in this work and found comparable. The concept of switching over to mMLC-based SRS/SRT is thus validated from dosimetric characteristics as well. (author)

  1. RF linear accelerators for medical and industrial applications

    CERN Document Server

    Hanna, Samy

    2012-01-01

    This unique resource offers you a clear overview of medical and industrial accelerators. Using minimal mathematics, this book focuses on offering thorough explanations of basic concepts surrounding the operation of accelerators. you find well illustrated discussions designed to help you use accelerator-based systems in a safer, more productive, and more reliable manner.This practical book details the manufacturing process for producing accelerators for medical and industrial applications. You become knowledgeable about the commonly encountered real-world manufacturing issues and potential sources of defects which help you avoid costly production problems. From principles of operation and the role of accelerators in cancer radiation therapy, to manufacturing techniques and future trends in accelerator design and applications, this easy-to-comprehend volume quickly brings you up-to-speed with the critical concepts you need to understand for your work in the field.

  2. Whole body electron therapy in mycosis fungoides - a successful translational technique achieved by modification of an established linear accelerator

    International Nuclear Information System (INIS)

    A translational technique, adapting an established MEL SL75/10 linear accelerator, which gives a satisfactory physical and clinical 3 MeV whole-body electron treatment in mycosis fungoides is described. Tolerance of the patients proved excellent and 16 out of 21 achieved satisfactory remission of the disease. In spite of delivering significant skin doses it was possible to re-treat two relapsing patients without complications and with clinical success. (author)

  3. Induction linear accelerator for the free-electron laser

    Science.gov (United States)

    1986-12-01

    A new design for an induction accelerator for FELs is proposed. The operation of the accelerator, which is based on Faraday's laws, is discussed. The use of an oxide or a dispenser cathode for the high-brightness injector of the accelerator is examined. The designs of the induction cells and nonlinear magnetic pulse compressor for the FELs are described. Ten induction cells form an induction module that is driven by the nonlinear magnetic pulse generator. An experimental test accelerator (ETA) has been developed and is being tested. Diagrams of the injector, induction cell, nonlinear magnetic pulse generator, and the ETA are presented.

  4. Accelerating structures pre-stripping section the milac heavy ion linear Accelerator MILAC

    International Nuclear Information System (INIS)

    Researches on development of new variants of accelerating structures for acceleration of the ions with A/q=20 in pre-stripping section PSS-20 are carried out. On an initial part of acceleration of ions from 6 up to 150 keV/u high capture in process of acceleration of the injected ions is provided interdigital (IH) accelerating structure with Radio-Frequency Quadrupole (RFQ) focusing. On the second part of acceleration of ions from 150 keV/u up to 1 MeV/u the highest rate of acceleration is created interdigital (IH) accelerating structure with drift tubes with the modified radio-frequency focusing.

  5. 15-16 MeV electron linear accelerators for nondestructive testing

    International Nuclear Information System (INIS)

    15-16 MeV electron linear accelerators for nondestructive testing (ND) are described. The accelerators are intended for ND of the articles with great thickness by means of radiographic, introscopic and tomographic methods. Main characteristics of these accelerators are presented. The automatic control system based on the PC compatible controllers is described in details

  6. A beam-matching concept for medical linear accelerators

    DEFF Research Database (Denmark)

    Sjöström, David; Bjelkengren, Ulf; Ottosson, Wiviann;

    2009-01-01

    not revealed by the vendor-defined acceptance criteria, whereas the other six accelerators were satisfactorily matched. The beam-matching acceptance criteria defined by the vendor are not strict enough to guarantee optimal beam-match. Deviations related to dose calculations and to beam-matched accelerators may...

  7. High-power proton linear accelerators for neutron generators and ADS (projects review)

    CERN Document Server

    Lazarev, N V

    2000-01-01

    The review of the suggestions of superpower linear accelerators for electric nuclear plants and high intensive neutron generators is given. The most important engineering resolutions, characteristics and state of the art of the linear accelerators with middle power of accelerated beam in the range from 1 to 100 MW: APT, SNS, JAERI/KEK, TRISPAL, TRASCO, ESS, KOMAC, Energy Amplifier, IFMIF, collaborative suggestions of ITEhF, MRTI and IFVEh, and other scientific centers are discussed

  8. Missile Acceleration Controller Design using PI and Time-Delay Adaptive Feedback Linearization Methodology

    OpenAIRE

    Lee, Chang-Hun; Seo, Min-Guk; Tahk, Min-Jea; Lee, Jin-Ik; Jun, Byung-Eul

    2012-01-01

    A straight forward application of feedback linearization to the missile autopilot design for acceleration control may be limited due to the nonminimum characteristics and the model uncertainties. As a remedy, this paper presents a cascade structure of an acceleration controller based on approximate feedback linearization methodology with a time-delay adaptation scheme. The inner loop controller is constructed by applying feedback linearization to the approximate system which is a minimum phas...

  9. Darmstadt Linear Accelerator (DALINAC) Research Laboratory. Status report - July 1988

    International Nuclear Information System (INIS)

    The status of the DALINAC project is reviewed. The accelerator and the experimental facilities are described, and a free-electron laser project is considered. Furthermore, experiments on inelastic electron scattering on nuclei and atomic systems are listed. (HSI)

  10. SU-E-T-197: Helical Cranial-Spinal Treatments with a Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, J; Bernard, D; Liao, Y; Templeton, A; Turian, J; Chu, J [Rush University Medical Center, Chicago, IL (United States)

    2014-06-01

    Purpose: Craniospinal irradiation (CSI) of systemic disease requires a high level of beam intensity modulation to reduce dose to bone marrow and other critical structures. Current helical delivery machines can take 30 minutes or more of beam-on time to complete these treatments. This pilot study aims to test the feasibility of performing helical treatments with a conventional linear accelerator using longitudinal couch travel during multiple gantry revolutions. Methods: The VMAT optimization package of the Eclipse 10.0 treatment planning system was used to optimize pseudo-helical CSI plans of 5 clinical patient scans. Each gantry revolution was divided into three 120° arcs with each isocenter shifted longitudinally. Treatments requiring more than the maximum 10 arcs used multiple plans with each plan after the first being optimized including the dose of the others (Figure 1). The beam pitch was varied between 0.2 and 0.9 (couch speed 5- 20cm/revolution and field width of 22cm) and dose-volume histograms of critical organs were compared to tomotherapy plans. Results: Viable pseudo-helical plans were achieved using Eclipse. Decreasing the pitch from 0.9 to 0.2 lowered the maximum lens dose by 40%, the mean bone marrow dose by 2.1% and the maximum esophagus dose by 17.5%. (Figure 2). Linac-based helical plans showed dose results comparable to tomotherapy delivery for both target coverage and critical organ sparing, with the D50 of bone marrow and esophagus respectively 12% and 31% lower in the helical linear accelerator plan (Figure 3). Total mean beam-on time for the linear accelerator plan was 8.3 minutes, 54% faster than the tomotherapy average for the same plans. Conclusions: This pilot study has demonstrated the feasibility of planning pseudo-helical treatments for CSI targets using a conventional linac and dynamic couch movement, and supports the ongoing development of true helical optimization and delivery.

  11. A new approach to modeling linear accelerator systems

    International Nuclear Information System (INIS)

    A novel computer code is being developed to generate system level designs of radiofrequency ion accelerators with specific applications to machines of interest to Accelerator Driven Transmutation Technologies (ADTT). The goal of the Accelerator System Model (ASM) code is to create a modeling and analysis tool that is easy to use, automates many of the initial design calculations, supports trade studies used in accessing alternate designs and yet is flexible enough to incorporate new technology concepts as they emerge. Hardware engineering parameters and beam dynamics are to be modeled at comparable levels of fidelity. Existing scaling models of accelerator subsystems were used to produce a prototype of ASM (version 1.0) working within the Shell for Particle Accelerator Related Code (SPARC) graphical user interface. A small user group has been testing and evaluating the prototype for about a year. Several enhancements and improvements are now being developed. The current version of ASM is described and examples of the modeling and analysis capabilities are illustrated. The results of an example study, for an accelerator concept typical of ADTT applications, is presented and sample displays from the computer interface are shown

  12. Evaluation of the linearity characteristic of the cone-beam CT fixed on the Varian 23EX linear accelerator

    International Nuclear Information System (INIS)

    Objective: To investigate the CT number linearity of the cone-beam CT (CBCT) images at the different spatial locations in the scanning area. Methods: The Catphan 504 phantom at the different locations are scanned repeatedly using the CBCT on the Varian 23EX linear accelerator. The phantom is located the isocenter point, eccentric 3 cm, eccentric 6 cm, and different points on the z-axis successively on the accelerator. The scanned mode is the standard head mode. The reconstructive thickness is 2.5 cm. The different densities inserts of CTP 4.4 module on the different locations are measured via Eclips treatment planning system (TPS) and computed by Matlab 7.0 and the CT linear fitting are then processed. In order to understand better the linear distribution along with the value of CT in the spatial distribution the results are compared with the fan-beam CT. Results: Phantom studies show that: CBCT has good linearity performance not only under the standard header (body) of the scanning conditions, but also on such locations including the cross-sectional, the sagittal, the coronal plane and the eccentric position (R2>0.953). Bowtie filtration device dose not change the CT linearity but changes the value of CT. Conclusions: The linearity of X-ray CBCT on the Varian linear accelerator is favorable. CBCT will be used in the TPS dose calculation via further correction of the CT value. (authors)

  13. A dosimetric characterization of a novel linear accelerator collimator

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, C. M.; Weston, S. J., E-mail: steve.weston@leedsth.nhs.uk; Cosgrove, V. C. [Leeds Cancer Centre, Bexley Wing, St. James’ University Hospital, Leeds LS9 7TF (United Kingdom); Thwaites, D. I. [Institute of Medical Physics, School of Physics, University of Sydney, Sydney NSW 2006, Australia and Division of Medical Physics, Leeds Institute of Genetics, Health and Therapeutics, University of Leeds, Leeds LS2 9JT (United Kingdom)

    2014-03-15

    Purpose: The aim of this work is to characterize a new linear accelerator collimator which contains a single pair of sculpted diaphragms mounted orthogonally to a 160 leaf multileaf collimator (MLC). The diaphragms have “thick” regions providing full attenuation and “thin” regions where attenuation is provided by both the leaves and the diaphragm. The leaves are mounted on a dynamic leaf guide allowing rapid leaf motion and leaf travel over 350 mm. Methods: Dosimetric characterization, including assessment of leaf transmission, leaf tip transmission, penumbral width, was performed in a plotting tank. Head scatter factor was measured using a mini-phantom and the effect of leaf guide position on output was assessed using a water phantom. The tongue and groove effect was assessed using multiple exposures on radiochromic film. Leaf reproducibility was assessed from portal images of multiple abutting fields. Results: The maximum transmission through the multileaf collimator is 0.44% at 6 MV and 0.52% at 10 MV. This reduced to 0.22% and 0.27%, respectively, when the beam passes through the dynamic leaf guide in addition to the MLC. The maximum transmission through the thick part of the diaphragm is 0.32% and 0.36% at 6 and 10 MV. The combination of leaf and diaphragm transmission ranges from 0.08% to 0.010% at 6 MV and 0.10% to 0.14% depending on whether the shielding is through the thick or thin part of the diaphragm. The off-axis intertip transmission for a zero leaf gap is 2.2% at 6 and 10 MV. The leaf tip penumbra for a 100 × 100 mm field ranges from 5.4 to 4.3 mm at 6 and 10 MV across the full range of leaf motion when measured in the AB direction, which reduces to 4.0–3.4 mm at 6 MV and 4.5–3.8 mm at 10 MV when measured in the GT direction. For a 50 × 50 mm field, the diaphragm penumbra ranges from 4.3 to 3.7 mm at 6 MV and 4.5 to 4.1 mm at 10 MV in the AB direction and 3.7 to 3.2 mm at 6 MV and 4.2 to 3.7 mm when measured in the GT direction. The

  14. Computation of Normal Conducting and Superconducting Linear Accelerator (LINAC) Availabilities

    International Nuclear Information System (INIS)

    A brief study was conducted to roughly estimate the availability of a superconducting (SC) linear accelerator (LINAC) as compared to a normal conducting (NC) one. Potentially, SC radio frequency cavities have substantial reserve capability, which allows them to compensate for failed cavities, thus increasing the availability of the overall LINAC. In the initial SC design, there is a klystron and associated equipment (e.g., power supply) for every cavity of an SC LINAC. On the other hand, a single klystron may service eight cavities in the NC LINAC. This study modeled that portion of the Spallation Neutron Source LINAC (between 200 and 1,000 MeV) that is initially proposed for conversion from NC to SC technology. Equipment common to both designs was not evaluated. Tabular fault-tree calculations and computer-event-driven simulation (EDS) computer computations were performed. The estimated gain in availability when using the SC option ranges from 3 to 13% under certain equipment and conditions and spatial separation requirements. The availability of an NC LINAC is estimated to be 83%. Tabular fault-tree calculations and computer EDS modeling gave the same 83% answer to within one-tenth of a percent for the NC case. Tabular fault-tree calculations of the availability of the SC LINAC (where a klystron and associated equipment drive a single cavity) give 97%, whereas EDS computer calculations give 96%, a disagreement of only 1%. This result may be somewhat fortuitous because of limitations of tabular fault-tree calculations. For example, tabular fault-tree calculations can not handle spatial effects (separation distance between failures), equipment network configurations, and some failure combinations. EDS computer modeling of various equipment configurations were examined. When there is a klystron and associated equipment for every cavity and adjacent cavity, failure can be tolerated and the SC availability was estimated to be 96%. SC availability decreased as

  15. Proceedings of the Oak Ridge Electron Linear Accelerator (ORELA) Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, M.E.

    2006-02-27

    The Oak Ridge National Laboratory (ORNL) organized a workshop at ORNL July 14-15, 2005, to highlight the unique measurement capabilities of the Oak Ridge Electron Linear Accelerator (ORELA) facility and to emphasize the important role of ORELA for performing differential cross-section measurements in the low-energy resonance region that is important for nuclear applications such as nuclear criticality safety, nuclear reactor and fuel cycle analysis, stockpile stewardship, weapons research, medical diagnosis, and nuclear astrophysics. The ORELA workshop (hereafter referred to as the Workshop) provided the opportunity to exchange ideas and information pertaining to nuclear cross-section measurements and their importance for nuclear applications from a variety of perspectives throughout the U.S. Department of Energy (DOE). Approximately 50 people, representing DOE, universities, and seven U.S. national laboratories, attended the Workshop. The objective of the Workshop was to emphasize the technical community endorsement for ORELA in meeting nuclear data challenges in the years to come. The Workshop further emphasized the need for a better understanding of the gaps in basic differential nuclear measurements and identified the efforts needed to return ORELA to a reliable functional measurement facility. To accomplish the Workshop objective, nuclear data experts from national laboratories and universities were invited to provide talks emphasizing the unique and vital role of the ORELA facility for addressing nuclear data needs. ORELA is operated on a full cost-recovery basis with no single sponsor providing complete base funding for the facility. Consequently, different programmatic sponsors benefit by receiving accurate cross-section data measurements at a reduced cost to their respective programs; however, leveraging support for a complex facility such as ORELA has a distinct disadvantage in that the programmatic funds are only used to support program

  16. Proceedings of the Oak Ridge Electron Linear Accelerator (ORELA) Workshop

    International Nuclear Information System (INIS)

    The Oak Ridge National Laboratory (ORNL) organized a workshop at ORNL July 14-15, 2005, to highlight the unique measurement capabilities of the Oak Ridge Electron Linear Accelerator (ORELA) facility and to emphasize the important role of ORELA for performing differential cross-section measurements in the low-energy resonance region that is important for nuclear applications such as nuclear criticality safety, nuclear reactor and fuel cycle analysis, stockpile stewardship, weapons research, medical diagnosis, and nuclear astrophysics. The ORELA workshop (hereafter referred to as the Workshop) provided the opportunity to exchange ideas and information pertaining to nuclear cross-section measurements and their importance for nuclear applications from a variety of perspectives throughout the U.S. Department of Energy (DOE). Approximately 50 people, representing DOE, universities, and seven U.S. national laboratories, attended the Workshop. The objective of the Workshop was to emphasize the technical community endorsement for ORELA in meeting nuclear data challenges in the years to come. The Workshop further emphasized the need for a better understanding of the gaps in basic differential nuclear measurements and identified the efforts needed to return ORELA to a reliable functional measurement facility. To accomplish the Workshop objective, nuclear data experts from national laboratories and universities were invited to provide talks emphasizing the unique and vital role of the ORELA facility for addressing nuclear data needs. ORELA is operated on a full cost-recovery basis with no single sponsor providing complete base funding for the facility. Consequently, different programmatic sponsors benefit by receiving accurate cross-section data measurements at a reduced cost to their respective programs; however, leveraging support for a complex facility such as ORELA has a distinct disadvantage in that the programmatic funds are only used to support program

  17. Beam operation aspects for the MYRRHA linear accelerator

    International Nuclear Information System (INIS)

    The aim of the MYRRHA (Multi-purpose Hybrid Research Reactor for High-tech Applications) project is to demonstrate the technical feasibility of transmutation in a 100 MWth accelerator-driven System (ADS) by building a new flexible irradiation complex in Mol (Belgium). The MYRRHA Facility requires a 600 MeV accelerator delivering a maximum proton flux of 4 mA in continuous operation with an additional requirement for exceptional reliability. This paper describes the current status of this ADS accelerator design and focuses on the specific aspects related to beam operation such as beam time structure requirements, beam power control and ramp-up strategies, beam reconfiguration schemes in fault cases and beam instrumentation needs. (authors)

  18. Artificial intelligence techniques for tuning linear induction accelerators

    International Nuclear Information System (INIS)

    The authors developed an expert system that acts as an intelligent assistant for tuning particle beam accelerators called MAESTRO - Model and Expert System Tuning Resource of Operators. MAESTRO maintains a knowledge base of the accelerator containing not only the interconnections of the beamline components, but also their physical attributes such as measured magnet tilts, offsets, and field profiles. MAESTRO incorporates particle trajectory and beam envelope models which are coupled to the knowledge base permitting large numbers of real-time orbit and envelope calculations in the control-room environment. To data the authors have used this capability in three ways: (1) to implement a tuning algorithm for minimizing transverse beam motion, (2) to produce a beam waist with arbitrary radius at the entrance to a brightness diagnostic, and (3) to measure beam energy along the accelerator by fitting orbits to focusing and steering sweeps

  19. Cavity dimensions calculation of a medical linear electron accelerator

    International Nuclear Information System (INIS)

    The main goal of this work is designing the cavity of an accelerator and performing its calculations. By choosing π/2 oscillation mode and using Super fish code, cavity dimensions for the desired parameters were calculated. The most important dimension for determining the resonance frequency is the radius of cylindrical cavity. The required precision for the cavity construction has been obtained by calculating the frequency variations versus the dimensions variation. Also, with the resulted electric field from Super fish code, its Fourier expansion, and considering the unidirectional components of the traveling waves, the major effect of one component in accelerating and its proper velocity have been demonstrated.

  20. Characterizing THz Coherent Synchrotron Radiation at Femtosecond Linear Accelerator

    Institute of Scientific and Technical Information of China (English)

    LIN Xu-Ling; ZHANG Jian-Bing; LU YU; LUO Feng; LU Shan-Liang; YU Tie-Min; DAI Zhi-Min

    2009-01-01

    The generation and observation of coherent THz synchrotron radiation from femtosecond electron bunches in the Shanghai Institute of Applied Physics femtosecond accelerator device is reported.We describe the experiment setup and present the first result of THz radiation properties such as power and spectrum.

  1. Performance review of thermionic electron gun developed for RF linear accelerators at RRCAT

    International Nuclear Information System (INIS)

    RRCAT is engaged in development of RF electron linear accelerator for irradiation of industrial and agricultural products. Thermionic electron gun is primary source for this accelerator as beam current in the RF accelerator is modest and thermionic emission is most prevalent option for electron gun development. An electron gun has to meet high cathode emission capability, low filament power, good accessibility for cathode replacement and should provide short time for maintenance. Electron linear accelerator up to beam energy of 10 MeV require electron source of 45-50 keV beam energy and emission current of 1 A. Electron optics of gun and electron beam profile simulations were carried out using CST's particle tracking code and EGUN code. Triode type electron gun of cathode voltage 50 kV pulsed has been designed, developed and integrated with 10 MeV electron linear accelerators at RRCAT. Beam current of more than 600 mA has been measured with faraday cup in the test stand developed for characterizing the electron gun. Two accelerators one is imported and another one developed indigenously has been energized using this electron gun. Beam energy of 5-10 MeV has been achieved with beam current of 250-400 mA by integrating this electron gun with the linear accelerator. This paper reviews the performance of indigenously developed electron gun for both linear accelerators. (author)

  2. An organizational survey of the Stanford Linear Accelerator Center

    Energy Technology Data Exchange (ETDEWEB)

    Shurberg, D.A.; Haber, S.B.

    1991-11-01

    At the request of the Department of Energy, an Organizational Survey (OS) was administered at the Stanford Accelerator Center (SLAC). The OS measured employees` opinions on subjects such as organizational culture, communication, commitment, group cohesion, coordination, safety, environmental issues, and job satisfaction. The result of this work was a quantitative measure of the notion of culture at the SLAC site. This report presents these results and discusses their interpretation.

  3. An organizational survey of the Stanford Linear Accelerator Center

    Energy Technology Data Exchange (ETDEWEB)

    Shurberg, D.A.; Haber, S.B.

    1991-11-01

    At the request of the Department of Energy, an Organizational Survey (OS) was administered at the Stanford Accelerator Center (SLAC). The OS measured employees' opinions on subjects such as organizational culture, communication, commitment, group cohesion, coordination, safety, environmental issues, and job satisfaction. The result of this work was a quantitative measure of the notion of culture at the SLAC site. This report presents these results and discusses their interpretation.

  4. Linear accelerator laboratory progress report: July 1983 - October 1985

    International Nuclear Information System (INIS)

    Different experiments presented are Asterix at Lear (CERN), DM2 at DCI (Orsay), NA3 and NA9 at SPS (CERN), NA9 at SPS, Cello at Desy (Hamburg), NA14 and NA31 at SPS, UA2 at SpantipS (CERN), the experiment ''proton meanlife'' at the underground laboratory of Modane. Experiments in preparation are Aleph (Lep), Delphi (Lep), H1. Technical projects are researches in acceleration techniques, experimental data acquisition with Fastbus standard and event analysis in 3D graphics

  5. Linear IFMIF prototype accelerator (LIPAc) control system: design and development

    OpenAIRE

    Calvo Pinto, Julio

    2014-01-01

    Distributed real time control systems in scientific instruments, such as particle accelerators or telescopes, have emerged as a solution to control multiple interconnected devices, which required constant attention and observation, along with a complete integration of each of its parts. This enhancement is provided by the intense technological development that control devices have suffered in recent years. With respect to the control software, libraries and applications have also emerged in r...

  6. Cryogenic system for the MYRRHA superconducting linear accelerator

    Science.gov (United States)

    Chevalier, Nicolas R.; Junquera, Tomas; Thermeau, Jean-Pierre; Romão, Luis Medeiros; Vandeplassche, Dirk

    2014-01-01

    SCKṡCEN, the Belgian Nuclear Research Centre, is designing MYRRHA, a flexible fast spectrum research reactor (80 MWth), conceived as an accelerator driven system (ADS), able to operate in sub-critical and critical modes. It contains a continuous-wave (CW) superconducting (SC) proton accelerator of 600 MeV, a spallation target and a multiplying core with MOX fuel, cooled by liquid lead-bismuth (Pb-Bi). From 17 MeV onward, the SC accelerator will consist of 48 β=0.36 spoke-loaded cavities (352 MHz), 34 β=0.47 elliptical cavities (704 MHz) and 60 β=0.65 elliptical cavities (704 MHz). We present an analysis of the thermal loads and of the optimal operating temperature of the cryogenic system. In particular, the low operating frequency of spoke cavities makes their operation in CW mode possible both at 4.2 K or at 2 K. Our analysis outlines the main factors that determine at what temperature the spoke cavities should be operated. We then present different cryogenic fluid distribution schemes, important characteristics (storage, transfer line, etc.) and the main challenges offered by MYRRHA in terms of cryogenics.

  7. Cryogenic system for the MYRRHA superconducting linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Chevalier, Nicolas R.; Junquera, Tomas [Accelerators and Cryogenic Systems, 86, rue de Paris, 91400 Orsay (France); Thermeau, Jean-Pierre [Institut de Physique Nucléaire, Université Paris Sud, 91400 Orsay (France); Romão, Luis Medeiros; Vandeplassche, Dirk [SCK-CEN, Boeretang 200, 2400 Mol (Belgium)

    2014-01-29

    SCK⋅CEN, the Belgian Nuclear Research Centre, is designing MYRRHA, a flexible fast spectrum research reactor (80 MW{sub th}), conceived as an accelerator driven system (ADS), able to operate in sub-critical and critical modes. It contains a continuous-wave (CW) superconducting (SC) proton accelerator of 600 MeV, a spallation target and a multiplying core with MOX fuel, cooled by liquid lead-bismuth (Pb-Bi). From 17 MeV onward, the SC accelerator will consist of 48 β=0.36 spoke-loaded cavities (352 MHz), 34 β=0.47 elliptical cavities (704 MHz) and 60 β=0.65 elliptical cavities (704 MHz). We present an analysis of the thermal loads and of the optimal operating temperature of the cryogenic system. In particular, the low operating frequency of spoke cavities makes their operation in CW mode possible both at 4.2 K or at 2 K. Our analysis outlines the main factors that determine at what temperature the spoke cavities should be operated. We then present different cryogenic fluid distribution schemes, important characteristics (storage, transfer line, etc.) and the main challenges offered by MYRRHA in terms of cryogenics.

  8. Jacobs Engineering Group Inc. receives architectural and engineering design contract from Stanford Linear Accelerator Centre

    CERN Multimedia

    2004-01-01

    "Jacobs Engineering Group Inc. announced that a subsidiary company won a contract from Stanford Linear Accelerator Center (SLAC), to provide architectural and engineering design services for the Linac Coherent Light Source (LCLS) conventional facilities" (1/2 page)

  9. FLUKA Monte Carlo for Basic Dosimetric Studies of Dual Energy Medical Linear Accelerator

    OpenAIRE

    K. Abdul Haneefa; T. Siji Cyriac; M. M. Musthafa; Ganapathi Raman, R.; Hridya, V. T.; A Siddhartha; Shakir, K. K.

    2014-01-01

    General purpose Monte Carlo code for simulation of particle transport is used to study the basic dosimetric parameters like percentage depth dose and dose profiles and compared with the experimental measurements from commercial dual energy medical linear accelerator. Varian Clinac iX medical linear accelerator with dual energy photon beams (6 and 15 MV) is simulated using FLUKA. FLAIR is used to visualize and edit the geometry. Experimental measurements are taken for 100 cm source-to-surface ...

  10. A threshold for laser-driven linear particle acceleration in unbounded vacuum

    OpenAIRE

    Wong, L. J.; Kärtner, F. X.

    2011-01-01

    We hypothesize that a charged particle in unbounded vacuum can be substantially accelerated by a force linear in the electric field of a propagating electromagnetic wave only if the accelerating field is capable of bringing the particle to a relativistic energy in its initial rest frame during the interaction. We consequently derive a general formula for the acceleration threshold of such schemes and support our conclusion with the results of numerical simulations over a broad range of parame...

  11. Microwave channel of a 40-MeV electron linear accelerator

    International Nuclear Information System (INIS)

    The RELUS-6, electron linear accelerator for an energy of 40 MeV microwave supply system for four standing-wave accelerating sections, and a pulsed current of 100 mA, have been developed with the microwave channel including a strip bridge, a phase shifter, a directional coupler, a waveguide bridge, and a waveguide water load

  12. Electron linear accelerator with synchronous power supply of a HF device and an electron gun

    International Nuclear Information System (INIS)

    The paper presents synchronous pulse power supply circuits of HF-generator and of the cathode of an electron gun of LUE-8/5 electron linear accelerator. Application of the given circuit of pulse power supply enables to reduce accelerator device dimensions. 1 fig

  13. Traveling wave linear accelerator with RF power flow outside of accelerating cavities

    Energy Technology Data Exchange (ETDEWEB)

    Dolgashev, Valery A.

    2016-06-28

    A high power RF traveling wave accelerator structure includes a symmetric RF feed, an input matching cell coupled to the symmetric RF feed, a sequence of regular accelerating cavities coupled to the input matching cell at an input beam pipe end of the sequence, one or more waveguides parallel to and coupled to the sequence of regular accelerating cavities, an output matching cell coupled to the sequence of regular accelerating cavities at an output beam pipe end of the sequence, and output waveguide circuit or RF loads coupled to the output matching cell. Each of the regular accelerating cavities has a nose cone that cuts off field propagating into the beam pipe and therefore all power flows in a traveling wave along the structure in the waveguide.

  14. Low loss RF cavity for high gradient linear accelerators

    CERN Document Server

    Żakowicz, Władysław

    2011-01-01

    Composite resonator, in the form of a spherical conducting cavity with a smaller dielectric sphere located at its center, is proposed as an accelerating unit for linacs. Electron trajectory is nearly tangent to the dielectric sphere. Interaction of an ultra relativistic electron with a convenient electromagnetic mode in such a resonator is discussed and compared to a typical accelerating unit of most linacs, i.e., a cylindrical resonator operating at the TM n = 0 mode. The lowest frequency modes for higher spherical harmonic index l > 4 concentrate near the surface of the internal dielectric sphere. This lowers significantly the skin effect losses at the conducting wall. Adding them to the losses in the non perfect dielectric sphere, we compare the result to the losses in typical operating cavities of existing linacs. Assuming that the electron trajectory segments within both cavities are the same, we calculate the ratio of the maximal electron energy gain in the spherical cavity Delta_E_s to that in the cyli...

  15. Electron Beam Focusing in the Linear Accelerator (linac)

    Science.gov (United States)

    Jauregui, Luis

    2015-10-01

    To produce consistent data with an electron accelerator, it is critical to have a well-focused beam. To keep the beam focused, quadrupoles (quads) are employed. Quads are magnets, which focus the beam in one direction (x or y) and defocus in the other. When two or more quads are used in series, a net focusing effect is achieved in both vertical and horizontal directions. At start up there is a 5% calibration error in the linac at Thomas Jefferson National Accelerator Facility. This means that the momentum of particles passing through the quads isn't always what is expected, which affects the focusing of the beam. The objective is to find exactly how sensitive the focusing in the linac is to this 5% error. A linac was simulated, which contained 290 RF Cavities with random electric fields (to simulate the 5% calibration error), and a total momentum kick of 1090 MeV. National Science Foundation, Department of Energy, Jefferson Lab, Old Dominion University.

  16. Optimal coupler and power setting for superconductive linear accelerators

    International Nuclear Information System (INIS)

    The modeling analysis presented in this paper addresses the question of how to achieve the highest vector sum gradient for all beam currents when individual cavities operate at different gradients due to their inherent quenching limitations. The analytical method explained here constitutes a step forward toward the operability of the International Linear Collider (ILC), Project X [8], or XFEL [7]. Unlike previously proposed methods [1, 2], this approach prevents cavities from quenching should the beam current be lower than its maximum value

  17. Off-axis beam quality change in linear accelerator x-ray beams

    International Nuclear Information System (INIS)

    The effective energy of the x-ray beam from linear accelerators changes as a function of the position in the beam due to nonuniform filtration by the flattening filter. In this work, the transmittance through a water column was measured in good geometry and the beam quality characterized in units of HVL in water. Measurements were made on a variety of linear accelerators from 4 to 10 MV. The beam energy decreased with increasing distance from the central ray for all accelerators measured

  18. A high-power rf linear accelerator for FELS [free-electron lasers

    International Nuclear Information System (INIS)

    This paper describes the design of a high average current rf linear accelerator suitable for driving short-wavelength free-electron lasers (FEL). It is concluded that the design of a room-temperature rf linear acelerator that can meet the stringent requirements of a high-power short-wavelength FEL appears possible. The accelerator requires the use of an advanced photoelectric injector that is under development; the accelerator components, however, do not require appreciable development. At these large beam currents, low-frequency, large-bore room-temperature cavities can be highly efficient and give all specified performance with minimal risk. 20 refs

  19. A heavy ion superconducting linear post-accelerator called ALPI

    International Nuclear Information System (INIS)

    The superconducting Linac known as ALPI will consist of quarter wave resonators (93 in total) made of copper, lead plated on their inner surface, cooled down to 4.2 K and independently phased. Ions, from silicon to uranium, accelerated by the 16 MV XTU Tandem, already operating will be further stripped of electrons and injected into the Linac, to achieve an energy from 6 up to 20 MeV/amu. The final part of the construction will include the installation of a positive ion source of the type ECR followed by a superconducting RFQ system of the equivalent voltage of 9-12 MeV. (R.P.) 7 refs.; 3 figs.; 2 tabs

  20. Note: A pulsed laser ion source for linear induction accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H., E-mail: bamboobbu@hotmail.com [Institute of Fluid Physics, China Academy of Engineering Physics, P.O. Box 919-106, Mianyang 621900 (China); School of Physics, Peking University, Beijing 100871 (China); Zhang, K.; Shen, Y.; Jiang, X.; Dong, P.; Liu, Y.; Wang, Y.; Chen, D.; Pan, H.; Wang, W.; Jiang, W.; Long, J.; Xia, L.; Shi, J.; Zhang, L.; Deng, J. [Institute of Fluid Physics, China Academy of Engineering Physics, P.O. Box 919-106, Mianyang 621900 (China)

    2015-01-15

    We have developed a high-current laser ion source for induction accelerators. A copper target was irradiated by a frequency-quadrupled Nd:YAG laser (266 nm) with relatively low intensities of 10{sup 8} W/cm{sup 2}. The laser-produced plasma supplied a large number of Cu{sup +} ions (∼10{sup 12} ions/pulse) during several microseconds. Emission spectra of the plasma were observed and the calculated electron temperature was about 1 eV. An induction voltage adder extracted high-current ion beams over 0.5 A/cm{sup 2} from a plasma-prefilled gap. The normalized beam emittance measured by a pepper-pot method was smaller than 1 π mm mrad.

  1. Beam control in the ETA-II linear induction accelerator

    International Nuclear Information System (INIS)

    Corkscrew beam motion is caused by chromatic aberration and misalignment of a focusing system. We have taken some measures to control the corkscrew motion on the ETA-II induction accelerator. To minimize chromatic aberration, we have developed an energy compensation scheme which reduces energy sweep and differential phase advance within a beam pulse. To minimize the misalignment errors, we have developed a time-independent steering algorithm which minimizes the observed corkscrew amplitude averaged over the beam pulse. The steering algorithm can be used even if the monitor spacing is much greater than the system's cyclotron wavelength and the corkscrew motion caused by a given misaligned magnet is fully developed, i.e., the relative phase advance is greater than 2π. (Author) 5 figs., 11 refs

  2. Linear scleroderma: a series of all clinical variants

    Directory of Open Access Journals (Sweden)

    Keerthi Jampani

    2014-04-01

    Full Text Available Morphea is a fibrosing disorder of the skin and subcutaneous tissues, wherein the overabundant collagen deposition destroys adnexal structures and hair follicles. In linear morphea erythematous or violaceous patches or plaques are seen with central sclerosis and active red border distributed in linear configuration which over time become sclerotic, white or hypopigmented. We report a series of cases encompassing all the three clinical variants of linear morphea. Case one had en coup de sabre deformity, case two had progressive facial hemiatrophy and case three had linear limb morphea with involvement of the face. This series is being reported for its rarity.

  3. Linear and nonlinear tremor acceleration characteristics in patients with Parkinson's disease

    International Nuclear Information System (INIS)

    The purpose of the study was to evaluate linear and nonlinear tremor characteristics of the hand in patients with Parkinson's disease (PD) and to compare the results with those of healthy old and young control subjects. Furthermore, the aim was to study correlation between tremor characteristics and clinical signs. A variety of nonlinear (sample entropy, cross-sample entropy, recurrence rate, determinism and correlation dimension) and linear (amplitude, spectral peak frequency and total power, and coherence) hand tremor parameters were computed from acceleration measurements for PD patients (n = 30, 68.3 ± 7.8 years), and old (n = 20, 64.2 ± 7.0 years) and young (n = 20, 18.4 ± 1.1 years) control subjects. Nonlinear tremor parameters such as determinism, sample entropy and cross-sample entropy were significantly different between the PD patients and healthy controls. These parameters correlated with the Unified Parkinson's disease rating scale (UPDRS), tremor and finger tapping scores, but not with the rigidity scores. Linear tremor parameters such as the amplitude and the maximum power (power corresponding to peak frequency) also correlated with the clinical findings. No major difference was detected in the tremor characteristics between old and young control subjects. The study revealed that tremor in PD patients is more deterministic and regular when compared to old or young healthy controls. The nonlinear tremor parameters can differentiate patients with PD from healthy control subjects and these parameters may have potential in the assessment of the severity of PD (UPDRS). (paper)

  4. Leakage of the Siemens 160 MLC multileaf collimator on a dual energy linear accelerator

    International Nuclear Information System (INIS)

    Multileaf collimators (MLCs) have been in clinical use for many years and meanwhile are commonly used to deliver intensity-modulated radiotherapy (IMRT) beams. For this purpose it is important to know their dosimetric properties precisely, one of them being inter- and intraleaf leakage. The Siemens 160 MLC features a single focus design with flat-sided and tilted leaves instead of tongue-and-groove. The leakage performance of the 160 MLC was investigated on a dual energy linear accelerator Siemens ARTISTE with 6 MV and 18 MV photon energies. While the intraleaf leakage amounted to nearly the same dose for 6 and for 18 MV, a much higher interleaf leakage for 6 MV was measured. It could be reduced by simply rotating the collimator, and also by changing the voltage applied to the beam steering coils. The leakage of the 160 MLC is shown to be sensitive to beam alignment. This is of special interest for dual energy accelerators, as the two focal spots of both energies, neither in position nor in shape, do not necessarily always coincide. As a consequence of that, a higher leakage can be expected for one out of two energies for the 160 MLC. (note)

  5. Linear accelerator driven (LADR) and regenerative reactors (LARR) for nuclear non-proliferation

    International Nuclear Information System (INIS)

    Linear accelerator breeders (LAB) could be used to produce fissile fuel in two modes, either with fuel reprocessing or without fuel reprocessing. With fuel reprocessing, the fissile material would be separated from the target and refabricated into a fuel element for use in a burner power reactor. Without reprocessing, the fissile material would be produced in-situ, either in a fresh fuel element or in a depleted or burned element after use in a power reactor. In the latter mode the fissile material would be increased in concentration for reuse in a power reactor. This system is called a Linear Accelerator Regenerative Reactor (LARR). The LAB can also be conceived of operating in a power production mode in which the spallation neutrons would be used to drive a subcritical assembly to produce power. This is called a Linear Accelerator Driven Reactor (LADR). A discussion is given of the principles and some of the technical problems of both types of accelerator breeders

  6. Non-perturbative aspects of particle acceleration in non-linear electrodynamics

    CERN Document Server

    Burton, David A; Wen, Haibao

    2015-01-01

    We undertake an investigation of particle acceleration in the context of non-linear electrodynamics. We deduce the maximum energy that an electron can gain in a non-linear density wave in a magnetised plasma, and we show that an electron can `surf' a sufficiently intense Born-Infeld electromagnetic plane wave and be strongly accelerated by the wave. The first result is valid for a large class of physically reasonable modifications of the linear Maxwell equations, whilst the second result exploits the special mathematical structure of Born-Infeld theory.

  7. The use of linear superconducting electron accelerator for subcritical reactor driving

    International Nuclear Information System (INIS)

    At NSC KIPT the opportunity of creating the installation with subcritical reactor, driven by the electron accelerator, is examined. For obtaining the maximal stream of neutrons from neutron-producing target at minimal density of energy emission, the electron energy should lay in the range 100-200 MeV, and the size of target should be maximal. The other important requirements are the beam continuity in time and the long-term stability of the accelerator parameters. The variants of using the superconducting linear accelerator on the basis of accelerating structure TESLA as a driver of subcritical reactor are considered. The basic design parameters and characteristics of this installation are submitted

  8. Linear Accelerator Test Facility at LNF Conceptual Design Report

    CERN Document Server

    Valente, Paolo; Bolli, Bruno; Buonomo, Bruno; Cantarella, Sergio; Ceccarelli, Riccardo; Cecchinelli, Alberto; Cerafogli, Oreste; Clementi, Renato; Di Giulio, Claudio; Esposito, Adolfo; Frasciello, Oscar; Foggetta, Luca; Ghigo, Andrea; Incremona, Simona; Iungo, Franco; Mascio, Roberto; Martelli, Stefano; Piermarini, Graziano; Sabbatini, Lucia; Sardone, Franco; Sensolini, Giancarlo; Ricci, Ruggero; Rossi, Luis Antonio; Rotundo, Ugo; Stella, Angelo; Strabioli, Serena; Zarlenga, Raffaele

    2016-01-01

    Test beam and irradiation facilities are the key enabling infrastructures for research in high energy physics (HEP) and astro-particles. In the last 11 years the Beam-Test Facility (BTF) of the DA{\\Phi}NE accelerator complex in the Frascati laboratory has gained an important role in the European infrastructures devoted to the development and testing of particle detectors. At the same time the BTF operation has been largely shadowed, in terms of resources, by the running of the DA{\\Phi}NE electron-positron collider. The present proposal is aimed at improving the present performance of the facility from two different points of view: extending the range of application for the LINAC beam extracted to the BTF lines, in particular in the (in some sense opposite) directions of hosting fundamental physics and providing electron irradiation also for industrial users; extending the life of the LINAC beyond or independently from its use as injector of the DA{\\Phi}NE collider, as it is also a key element of the electron/...

  9. Stereotactic radiosurgery for intracranial lesions using a linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Shoji, Kazufusa [Mie Univ., Tsu (Japan). School of Medicine; Toyota, Shun; Seta, Hidetoshi [and others

    1996-09-01

    Experiences in 47 cases of stereotactic radiosurgery were reported. The surgery was carried out using stereotactic radiosurgery system of Fisher STP system (Leibinger Co.). The accelerator was Clinac 2100c (Varian Co., 10 mV X ray) or EXL-15 SP (Mitsubishi Co., 6 mV) equipped with collimator. CT and MRI imaging data were firstly transported to the working station to determine the target volume, target coordinates and radiation dose. Irradiation from 90deg to -90deg directions from isocenter of the linac was done within an error of 1 mm after the actual measurement of the target on the port film. The treatment was necessary for 6-8 hr and and irradiation was essentially complete for it. The dose was 20 Gy for metastatic brain tumors (31 patients), 14-16 Gy for acoustic neuroma (1) and 16 Gy for arteriovenous malformation (1). The local control rate of the brain tumors was as high as 90%. The complication was cerebral necrosis (1 case) and exacerbation of neurological symptoms (1), which exhibited remission with steroid treatment. Thus stereotactic radiosurgery with linac made it possible to treat intracranial lesions without invasion effectively and safely. (K.H.)

  10. Leakage pattern of linear accelerator treatment heads from multiple vendors

    International Nuclear Information System (INIS)

    Full text: Patient life expectancy post-radiotherapy is becoming longer. Therefore, secondary cancers caused by radiotherapy treatment have more time to develop. Increasing attention is being given to out-of-field dose resulting from scatter and accelerator head leakage. Dose leakage from equivalent positions on Varian600C, Varian21-X, Siemens Primus and Elekta Synergy-II linacs were measured with TLD 100H dosimeter chips and compared. Treatment parameters such as field size and beam energy were altered. Leakage doses are presented as a percentage of the dose to isocentre (5 Gy). Results illustrate significant variations in leakage dose between linac models where no model emits consistently lower amounts of radiation leakage for all treatment parameters. Results are shown below. Leakage through the collimator assembly in different units is varying as a function of location and unit design by more than a factor of 10. Differences are more pronounced in comparing Varian or Elekta models, which are fitted with an additional collimator separate from the MLC leaves, to the Siemens model, which uses MLC leaves as its only secondary collimator. Further measurements are currently being taken at the patient plane with a directional detector system to determine the spatial distribution of high leakage sources.

  11. High-brightness ion and electron rf linear accelerators

    International Nuclear Information System (INIS)

    In the past, development work to increase the energy and intensity of particle accelerators tended to be pursued in separate directions, but now almost all modern applications have to achieve an intensity as high as possible at the desired energy, along with a very good beam quality in terms of the beam confinement, aiming, or focusing. The figure of merit used is the beam brightness, defined as the beam power (or current when the energy is fixed) divided by the phase space appropriate to the problem at hand. Phase space for the beam as a whole is six-dimensional, describing the physical size of the beam and change in size with time or distance; the area projected on one plane is called emittance. Achieving high intensity and good quality simultaneously is difficult, primarily because of nonlinear space- charge and focusing forces at nonrelativistic velocities and because of beam-breakup effects for relativistic beams. In recent years, substantial progress has been made in understanding the physics of these effects; some aspects are reviewed here and related to their impact on practical design aspects. 7 refs

  12. A comparison of robotic arm versus gantry linear accelerator stereotactic body radiation therapy for prostate cancer

    Science.gov (United States)

    Avkshtol, Vladimir; Dong, Yanqun; Hayes, Shelly B; Hallman, Mark A; Price, Robert A; Sobczak, Mark L; Horwitz, Eric M; Zaorsky, Nicholas G

    2016-01-01

    Prostate cancer is the most prevalent cancer diagnosed in men in the United States besides skin cancer. Stereotactic body radiation therapy (SBRT; 6–15 Gy per fraction, up to 45 minutes per fraction, delivered in five fractions or less, over the course of approximately 2 weeks) is emerging as a popular treatment option for prostate cancer. The American Society for Radiation Oncology now recognizes SBRT for select low- and intermediate-risk prostate cancer patients. SBRT grew from the notion that high doses of radiation typical of brachytherapy could be delivered noninvasively using modern external-beam radiation therapy planning and delivery methods. SBRT is most commonly delivered using either a traditional gantry-mounted linear accelerator or a robotic arm-mounted linear accelerator. In this systematic review article, we compare and contrast the current clinical evidence supporting a gantry vs robotic arm SBRT for prostate cancer. The data for SBRT show encouraging and comparable results in terms of freedom from biochemical failure (>90% for low and intermediate risk at 5–7 years) and acute and late toxicity (cancer-specific mortality) cannot be compared, given the indolent course of low-risk prostate cancer. At this time, neither SBRT device is recommended over the other for all patients; however, gantry-based SBRT machines have the abilities of treating larger volumes with conventional fractionation, shorter treatment time per fraction (~15 minutes for gantry vs ~45 minutes for robotic arm), and the ability to achieve better plans among obese patients (since they are able to use energies >6 MV). Finally, SBRT (particularly on a gantry) may also be more cost-effective than conventionally fractionated external-beam radiation therapy. Randomized controlled trials of SBRT using both technologies are underway. PMID:27574585

  13. VMC++ versus BEAMnrc: A comparison of simulated linear accelerator heads for photon beams

    International Nuclear Information System (INIS)

    BEAMnrc, a code for simulating medical linear accelerators based on EGSnrc, has been benchmarked and used extensively in the scientific literature and is therefore often considered to be the gold standard for Monte Carlo simulations for radiotherapy applications. However, its long computation times make it too slow for the clinical routine and often even for research purposes without a large investment in computing resources. VMC++ is a much faster code thanks to the intensive use of variance reduction techniques and a much faster implementation of the condensed history technique for charged particle transport. A research version of this code is also capable of simulating the full head of linear accelerators operated in photon mode (excluding multileaf collimators, hard and dynamic wedges). In this work, a validation of the full head simulation at 6 and 18 MV is performed, simulating with VMC++ and BEAMnrc the addition of one head component at a time and comparing the resulting phase space files. For the comparison, photon and electron fluence, photon energy fluence, mean energy, and photon spectra are considered. The largest absolute differences are found in the energy fluences. For all the simulations of the different head components, a very good agreement (differences in energy fluences between VMC++ and BEAMnrc <1%) is obtained. Only a particular case at 6 MV shows a somewhat larger energy fluence difference of 1.4%. Dosimetrically, these phase space differences imply an agreement between both codes at the <1% level, making VMC++ head module suitable for full head simulations with considerable gain in efficiency and without loss of accuracy

  14. Performance of the accelerating cavities at the superconducting Darmstadt linear accelerator (S-DALINAC)

    International Nuclear Information System (INIS)

    The 10 MeV injector of the superconducting 130 MeV electron accelerator at Darmstadt (S-DALINAC) produced its first beam in August 87, when a phase locked operation of its 5-cell capture section and two 20-cell structures was achieved for the first time. Status reports have been presented after the installation of the first and the second cryomodule of the main linac each one containing two 20-cell accelerating structures. The present report gives a brief description of the accelerator focusing on its main design parameters and its present status of installation. Results from some 550 hours of machine time for accelerator tests and from 950 hours of injector beamtime for atomic and nuclear physics experiments are summarized. Main emphasis is laid on the experience which was gained during this time with the performance of the superconducting cavities and associated equipment like couplers, tuners and windows. The development of a modest infrastructure for cavity treatment is in progress. The report describes the present status of installations and how to improve them. An outlook on how to proceed in the completion of the accelerator is also given. (N.K.)

  15. Analysis and measurement of focusing effects in a traveling wave linear accelerator

    International Nuclear Information System (INIS)

    For a recent precise linear accelerator, such as the x-ray free electron laser facility, SACLA, the beam orbit and the beam envelop should be properly calculated from the beam dynamics model of a traveling wave accelerating structure (TWA). Therefore, we compared a predicted beam orbit by a TWA model with a measured orbit by rf cavity beam position monitors. Although the beam orbit in the crest acceleration part was appropriately reproduced, that of the off-crest acceleration part did not agree with the prediction. We found out that the discrepancy came from a quadrupole field in the coupler cell of the TWA. The strength of the quadrupole field was estimated by using 3-dimensional rf simulation and the TWA model was modified by the addition of the quadrupole focusing effect. By using the modified model, the beam orbit was properly reproduced in both the crest acceleration part and the off-crest acceleration part. (author)

  16. Development of the pulsed power system of the accelerator module for the linear induction accelerator

    International Nuclear Information System (INIS)

    This paper presents a pulsed power system, the terminal load of which is an accelerator module, with this system, A 350 kV, 90 ns (FWHM) voltage with 30 ns rise-time accross the accelerating gap has been obtained. The jitter of the main switch operating at 280 kv is less than 1.5 ns (RMS). Further improvement on the performance of the coaxial field distortion switch is discussed and it is pointed out that the operating voltage of the switch can be increased by 8.2 %. If the triggering electrode is biased by means of equivalent electrical field stress. (author)

  17. New linear accelerator (Linac) design based on C-band accelerating structures for SXFEL facility

    Institute of Scientific and Technical Information of China (English)

    ZHANG Meng; GU Qiang

    2011-01-01

    A C-band accelerator structure is one promising technique for a compact XFEL facility.It is also attractive in beam dynamics in maintaining a high quality electron beam,which is an important factor in the performance of a free electron laser.In this paper,a comparison between traditional S-band and C-band accelerating structures is made based on the linac configuration of a Shanghai Soft X-ray Free Electron Laser (SXFEL) facility.Throughout the comprehensive simulation,we conclude that the C-band structure is much more competitive.

  18. Acquiring beam data for a flattening-filter free linear accelerator using organic scintillators

    International Nuclear Information System (INIS)

    Fibre-coupled organic scintillators have been proven a credible alternative to clinically implemented methods for radiotherapy dosimetry, primarily due to their water equivalence and good spatial resolution. Furthermore, the fast response of the scintillators can be exploited to perform time-resolved dosimetry on a highly detailed level. In this study, we present beam data for a Varian TrueBeam linear accelerator, which is capable of delivering flattening-filter free (FFF1) clinical X-ray beams. The beam data have been acquired using an in-house developed dosimetry system based on fibre-coupled organic scintillators. The presented data exhibit high accuracy and precision when compared with data obtained using commercial dosimetry methods, and agree well with results published in the literature. -- Highlights: •A dosimetry system based on fibre-coupled organic scintillators is presented. •The system is used for radiotherapy beams with and without flattening filter. •Measurements show good agreement with various commercial dosimeters

  19. Motion sickness and otolith sensitivity - A pilot study of habituation to linear acceleration

    Science.gov (United States)

    Potvin, A. R.; Sadoff, M.; Billingham, J.

    1977-01-01

    Astronauts, particularly in Skylab flights, experienced varying degrees of motion sickness lasting 3-5 days. One possible mechanism for this motion sickness adaptation is believed to be a reduction in otolith sensitivity with an attendant reduction in sensory conflict. In an attempt to determine if this hypothesis is valid, a ground-based pilot study was conducted on a vertical linear accelerator. The extent of habituation to accelerations which initially produced motion sickness was evaluated, along with the possible value of habituation training to minimize the space motion sickness problem. Results showed that habituation occurred for 6 of the 8 subjects tested. However, in tests designed to measure dynamic and static otolith function, no significant differences between pre- and post-habituation tests were observed. Cross habituation effects to a standard Coriolis acceleration test were not significant. It is unlikely that ground-based pre-habituation to linear accelerations of the type examined would alter susceptibility to space motion sickness.

  20. Linear accelerator of All-Union Scientific Research Institute of Experimental Physics for neutron spectrometry

    International Nuclear Information System (INIS)

    The electron linear accelerator intended for neutron spectrometry with a nominal energy of about 55 MeV at currents of 10 A in electron pulse repetition rate of 2400 Hz started in 1985 is described. The special features of linac construction, the measuring complex assembly, the results of spectrum measurements and neutron yield of uranium target are given. The possibilities of accelerator development for increasing the pulse current and pulse length shortening are considered. (orig.)

  1. Non-linear diffusive acceleration of heavy nuclei in supernova remnant shocks

    OpenAIRE

    Caprioli, D.; P. Blasi(INAF Arcetri); Amato, E.

    2010-01-01

    Abstract We describe a semi-analytical approach to non-linear diffusive shock acceleration in the case in which nuclei other than protons are also accelerated. The structure of the shock is determined by the complex interplay of all nuclei, and in turn this shock structure determines the spectra of all components. The magnetic field amplification upstream is described as due to streaming instability of all nuclear species. The amplified magnetic field is then taken into account for...

  2. Numerical analysis of acceleration obtained from pulsed-linear-MHD accelerator using model rocket engine

    International Nuclear Information System (INIS)

    To improve the thrust efficiency of a pulsed magnetohydrodynamic (MHD) accelerator, we perform numerical calculations that simulate the experimental conditions, which were used earlier, in an apparatus that include a model rocket engine. The one-fluid one-dimensional-MHD simulation results show agreement between the experimental and numerical results. We discuss simulation results for temporal and spatial distributions of the electrical conductivity and current density. (author)

  3. Solving Large Sparse Linear Systems in End-to-end Accelerator Structure Simulations

    International Nuclear Information System (INIS)

    This paper presents a case study of solving very large sparse linear systems in end-to-end accelerator structure simulations. Both direct solvers and iterative solvers are investigated. A parallel multilevel preconditioner based on hierarchical finite element basis functions is considered and has been implemented to accelerate the convergence of iterative solvers. A linear system with matrix size 93,147,736 and with 3,964,961,944 non-zeros from 3D electromagnetic finite element discretization has been solved in less than 8 minutes with 1024 CPUs on the NERSC IBM SP. The resource utilization as well as the application performance for these solvers is discussed

  4. penentuan energi efektif sinar x pada pesawat radioterapi linear accelerator (linac)

    OpenAIRE

    Fauziah, Fauziah

    2016-01-01

    ABSTRAC It research has been done about determination of X-ray effective energy at radiotherapy linear accelerator. This research used copper plates which had a different thickness with determination of Half Value Layer for each energy. The result of this research show that the energy 6 MeV are retrieved effective energy 2,714 MeV in HVL 4,500 mm and energy 10 MeV retrieved effective energy 4,231 MeV in HVL 4,500 mm. Key Words : Effective Energy, Half Value Layer, Linear Accelerator, c...

  5. A Threshold for Laser-Driven Linear Particle Acceleration in Unbounded Vacuum

    CERN Document Server

    Wong, Liang Jie

    2013-01-01

    We hypothesize that a charged particle in unbounded vacuum can be substantially accelerated by a force linear in the electric field of a propagating electromagnetic wave only if the accelerating field is capable of bringing the particle to a relativistic energy in its initial rest frame during the interaction. We consequently derive a general formula for the acceleration threshold of such schemes and support our conclusion with the results of numerical simulations over a broad range of parameters for different kinds of pulsed laser beams.

  6. Modulator of the LUEhK-20 electron-ion ring induction linear accelerator

    International Nuclear Information System (INIS)

    A powerful modulator - pulse generator of accelerating voltage of the LUEhK-20 electron-ion ring induction linear accelerator is described. The modulator parameters are: the 0.5 Ohm output load voltage is 50 kV, the load current is approximately 100 kA, the loading voltage pulse duration is 70-80 ns. Modulator is made using nonlinear circuits of power amplification by time compression of electromagnetic energy. Modulator is aimed at supply of 36 inductor accelerating section. A test start of the modulators without a beam is carried out, and total voltage of 1.8 MV is obtained at each section

  7. Electron beam dynamics in the DARHT-II linear induction accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Carl A [Los Alamos National Laboratory; Abeyta, Epifanio O [Los Alamos National Laboratory; Aragon, Paul [Los Alamos National Laboratory; Archuleta, Rita [Los Alamos National Laboratory; Cook, Gerald [Los Alamos National Laboratory; Dalmas, Dale [Los Alamos National Laboratory; Esquibel, Kevin [Los Alamos National Laboratory; Gallegos, Robert A [Los Alamos National Laboratory; Garnett, Robert [Los Alamos National Laboratory; Harrison, James F [Los Alamos National Laboratory; Johnson, Jeffrey B [Los Alamos National Laboratory; Jacquez, Edward B [Los Alamos National Laboratory; Mccuistian, Brian T [Los Alamos National Laboratory; Montoya, Nicholas A [Los Alamos National Laboratory; Nath, Subrata [Los Alamos National Laboratory; Nielsen, Kurt [Los Alamos National Laboratory; Oro, David [Los Alamos National Laboratory; Prichard, Benjamin [Los Alamos National Laboratory; Rowton, Lawrence [Los Alamos National Laboratory; Sanchez, Manolito [Los Alamos National Laboratory; Scarpetti, Raymond [Los Alamos National Laboratory; Schauer, Martin M [Los Alamos National Laboratory; Seitz, Gerald [Los Alamos National Laboratory; Schulze, Martin [Los Alamos National Laboratory; Bender, Howard A [Los Alamos National Laboratory; Broste, William B [Los Alamos National Laboratory; Carlson, Carl A [Los Alamos National Laboratory; Frayer, Daniel K [Los Alamos National Laboratory; Johnson, Douglas E [Los Alamos National Laboratory; Tom, C Y [Los Alamos National Laboratory; Trainham, C [NSTEC/STL; Williams, John [Los Alamos National Laboratory; Genoni, Thomas [VOSS; Hughes, Thomas [VOSS; Toma, Carsten [VOSS

    2008-01-01

    The DARHT-II linear induction accelerator (LIA) accelerates a 2-kA electron beam to more than 17 MeV. The beam pulse has a greater than 1.5-microsecond flattop region over which the electron kinetic energy is constant to within 1%. The beam dynamics are diagnosed with 21 beam-position monitors located throughout the injector, accelerator, and after the accelerator exit, where we also have beam imaging diagnostics. We discuss the tuning of the injector and accelerator, and present data for the resulting beam dynamics. We discuss the tuning procedures and other methods used to minimize beam motion, which is undesirable for its application as a bremsstrahlung source for multi-pulse radiography of exlosively driven hydrodynamic experiments. We also present beam stability measurements, which we relate to previous stability experiments at lower current and energy.

  8. Electron beam dynamics in the DARHT-II linear induction accelerator

    International Nuclear Information System (INIS)

    The DARHT-II linear induction accelerator (LIA) accelerates a 2-kA electron beam to more than 17 MeV. The beam pulse has a greater than 1.5-microsecond flattop region over which the electron kinetic energy is constant to within 1%. The beam dynamics are diagnosed with 21 beam-position monitors located throughout the injector, accelerator, and after the accelerator exit, where we also have beam imaging diagnostics. We discuss the tuning of the injector and accelerator, and present data for the resulting beam dynamics. We discuss the tuning procedures and other methods used to minimize beam motion, which is undesirable for its application as a bremsstrahlung source for multi-pulse radiography of exlosively driven hydrodynamic experiments. We also present beam stability measurements, which we relate to previous stability experiments at lower current and energy.

  9. Solving large-scale sparse eigenvalue problems and linear systems of equations for accelerator modeling

    International Nuclear Information System (INIS)

    The solutions of sparse eigenvalue problems and linear systems constitute one of the key computational kernels in the discretization of partial differential equations for the modeling of linear accelerators. The computational challenges faced by existing techniques for solving those sparse eigenvalue problems and linear systems call for continuing research to improve on the algorithms so that ever increasing problem size as required by the physics application can be tackled. Under the support of this award, the filter algorithm for solving large sparse eigenvalue problems was developed at Stanford to address the computational difficulties in the previous methods with the goal to enable accelerator simulations on then the world largest unclassified supercomputer at NERSC for this class of problems. Specifically, a new method, the Hemitian skew-Hemitian splitting method, was proposed and researched as an improved method for solving linear systems with non-Hermitian positive definite and semidefinite matrices.

  10. Standing Wave Linear Accelerators: An Investigation of the Fundamental Field Stability and Tuning Characteristics

    International Nuclear Information System (INIS)

    The first accelerators were designed as a tool in high-energy particle physics. Their development has given rise to numerous applications in industry, such as materials processing, sterilization, food preservation, and radiopharmaceutical product generation (Barbalat, 1994). Modern day linear accelerators for particle physics accelerate multiple bunches of electrons and positrons up to 50 GeV. Accelerators of the next generation, such as the Next Linear Collider (NLC), aim to accelerate the bunches initially to a center of mass of 500GeV and later to 1.5 TeV (Decking 2001, Miyamoto 2002, Phinney 2002). The NLC will operate under gradient fields on the order of 70 MV/m (Phinney, 2002). For all accelerators, two issues are fundamental for their construction: maximizing the efficiency of acceleration while, at the same time, preserving the luminosity of the beam. These issues are critically important in the design of the NLC. A linear accelerator operates as follows: An electron gun fires electrons into a structure that bunches the electrons and tightly focuses the beam. At the same time, a radiofrequency wave is fed into the accelerating structure. The electron bunches enter the accelerating structure in phase with the crest of the radiofrequency wave in order to achieve maximum energy. There are two principal types of accelerating structures: traveling wave (TW) and standing wave (SW). The electromagnetic wave in a TW structure travels in one direction; the electromagnetic wave in a SW structure travels in two directions. Many TW structures have been designed for the NLC, but recent experiments indicate that TW structures suffer from electrical breakdown at high gradients (Miller et. al., 2001). To address this problem, SW structures are being considered as the alternative for the NLC (Jones and Miller et. al., 2002). The input power required for an accelerating cavity increases with the length of the cavity (Miller et. al., 2001). Since SW structures can be made

  11. Proposed Physics Experiments for Laser-Driven Electron Linear Acceleration in a Dielectric Loaded Vacuum, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Byer, Robert L. [Stanford Univ., CA (United States). Dept. of Applied Physics. Edward L. Ginzton Lab.

    2016-07-08

    This final report summarizes the last three years of research on the development of advanced linear electron accelerators that utilize dielectric wave-guide vacuum channels pumped by high energy laser fields to accelerate beams of electrons.

  12. Spatiotemporal processing of linear acceleration: primary afferent and central vestibular neuron responses

    Science.gov (United States)

    Angelaki, D. E.; Dickman, J. D.

    2000-01-01

    Spatiotemporal convergence and two-dimensional (2-D) neural tuning have been proposed as a major neural mechanism in the signal processing of linear acceleration. To examine this hypothesis, we studied the firing properties of primary otolith afferents and central otolith neurons that respond exclusively to horizontal linear accelerations of the head (0.16-10 Hz) in alert rhesus monkeys. Unlike primary afferents, the majority of central otolith neurons exhibited 2-D spatial tuning to linear acceleration. As a result, central otolith dynamics vary as a function of movement direction. During movement along the maximum sensitivity direction, the dynamics of all central otolith neurons differed significantly from those observed for the primary afferent population. Specifically at low frequencies (neurons peaked in phase with linear velocity, in contrast to primary afferents that peaked in phase with linear acceleration. At least three different groups of central response dynamics were described according to the properties observed for motion along the maximum sensitivity direction. "High-pass" neurons exhibited increasing gains and phase values as a function of frequency. "Flat" neurons were characterized by relatively flat gains and constant phase lags (approximately 20-55 degrees ). A few neurons ("low-pass") were characterized by decreasing gain and phase as a function of frequency. The response dynamics of central otolith neurons suggest that the approximately 90 degrees phase lags observed at low frequencies are not the result of a neural integration but rather the effect of nonminimum phase behavior, which could arise at least partly through spatiotemporal convergence. Neither afferent nor central otolith neurons discriminated between gravitational and inertial components of linear acceleration. Thus response sensitivity was indistinguishable during 0.5-Hz pitch oscillations and fore-aft movements. The fact that otolith-only central neurons with "high

  13. The design of a simulated in-line side-coupled 6 MV linear accelerator waveguide

    Energy Technology Data Exchange (ETDEWEB)

    St Aubin, Joel; Steciw, Stephen; Fallone, B. G. [Department of Physics, University of Alberta, 11322-89 Avenue, Edmonton, Alberta T6G 2G7 (Canada) and Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Physics, University of Alberta, 11322-89 Avenue, Edmonton, Alberta T6G 2G7 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); and Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

    2010-02-15

    cylindrically uniform electron beam accelerating within the waveguide. The shifting and skewing of the electron beam were found to be greatest due to the effects of the side-coupling irises on the RF field. A further Monte Carlo study showed that this effect translated into a 1% asymmetry in a 40x40 cm{sup 2} field dose profile. Conclusions: A full 3D design for an in-line side-coupled 6 MV linear accelerator that emulates a common commercial waveguide has been given. The effect of the side coupling on the dose distribution has been shown to create a slight asymmetry, but overall does not affect the clinical applicability of the linac. The 3D in-line side-coupled linac model further provides a tool for the investigation of linac performance within an external magnetic field, which exists in an integrated linac-MR system.

  14. The design of a simulated in-line side-coupled 6 MV linear accelerator waveguide

    International Nuclear Information System (INIS)

    cylindrically uniform electron beam accelerating within the waveguide. The shifting and skewing of the electron beam were found to be greatest due to the effects of the side-coupling irises on the RF field. A further Monte Carlo study showed that this effect translated into a 1% asymmetry in a 40x40 cm2 field dose profile. Conclusions: A full 3D design for an in-line side-coupled 6 MV linear accelerator that emulates a common commercial waveguide has been given. The effect of the side coupling on the dose distribution has been shown to create a slight asymmetry, but overall does not affect the clinical applicability of the linac. The 3D in-line side-coupled linac model further provides a tool for the investigation of linac performance within an external magnetic field, which exists in an integrated linac-MR system.

  15. Linear induction accelerators made from pulse-line cavities with external pulse injection

    International Nuclear Information System (INIS)

    Two types of linear induction accelerator have been reported previously. In one, unidirectional voltage pulses are generated outside the accelerator and injected into the accelerator cavity modules, which contain ferromagnetic material to reduce energy losses in the form of currents induced, in parallel with the beam, in the cavity structure. In the other type, the accelerator cavity modules are themselves pulse-forming lines with energy storage and switches; parallel current losses are made zero by the use of circuits that generate bidirectional acceleration waveforms with a zero voltage-time integral. In a third type of design described here, the cavities are externally driven, and 100% efficient coupling of energy to the beam is obtained by designing the external pulse generators to produce bidirectional voltage waveforms with zero voltage-time integral. A design for such a pulse generator is described that is itself one hundred percent efficient and which is well suited to existing pulse power techniques. Two accelerator cavity designs are described that can couple the pulse from such a generator to the beam; one of these designs provides voltage doubling. Comparison is made between the accelerating gradients that can be obtained with this and the preceding types of induction accelerator

  16. Dosimetry and fast neutron energies characterization of photoneutrons produced in some medical linear accelerators

    Science.gov (United States)

    Khaled, N. E.; Attalla, E. M.; Ammar, H.; Khalil, W.

    2011-12-01

    This work focusses on the estimation of induced photoneutrons energy, fluence, and strength using nuclear track detector (NTD) (CR-39). Photoneutron energy was estimated for three different linear accelerators, LINACs as an example for the commonly used accelerators. For high-energy linear accelerators, neutrons are produced as a consequence of photonuclear reactions in the target nuclei, accelerator head, field-flattening filters and beam collimators, and other irradiated objects. NTD (CR-39) is used to evaluate energy and fluence of the fast neutron. Track length is used to estimate fast photoneutrons energy for linear accelerators (Elekta 10 MV, Elekta 15 MV, and Varian 15 MV). Results show that the estimated neutron energies for the three chosen examples of LINACs reveals neutron energies in the range of 1-2 MeV for 10 and 15 MV X-ray beams. The fluence of neutrons at the isocenter (Φtotal) is found to be (4×106 n cm2 Gy-1) for Elekta machine 10 MV. The neutron source strengths Q are calculated. It was found to be 0.2×1012 n Gy-1 X-ray at the isocenter. This work represents simple, low cost, and accurate methods of measuring fast neutrons dose and energies.

  17. Technique and dosimetry for total body irradiation with an 8-MV linear accelerator

    International Nuclear Information System (INIS)

    The aim of the study was to develop a method for calculation of the absorbed dose at an arbitrary point in the patient (adults and children). The method should be accurate but simple to use in clinical routine and it should as far as possible follow the recommendations by ICRU for conventional radiotherapy. An 8-MV linear accelerator is used with a diamond-shaped field and an isocentric technique at a focus-axis distance of 430 cm. The dose rate in an arbitrary point in the patient is calculated from the absorbed dose rate in dose maximum for a phantom size of 30 x 30 x 30 cm3 in the TBI field, an inverse square law factor, the tissue-maximum ratio, an equivalent field size correction factor determined from the patient contour using the Clarkson method, a factor correcting for lack of backscattering material, an off-axis output correction factor, and a factor that corrects for off-axis variations in effective photon beam energy and for oblique beam penetration of the patient. A personal computer is used for the dose calculations. The formula was tested with TLD measurements in a RT Humanoid (adult) phantom and in a Pedo-RT Humanoid (child) phantom. In vivo dose measurements are also presented

  18. Using of beam spoilers in linear accelerators with photons of 10 MV

    International Nuclear Information System (INIS)

    This work come along of the necessity to utilize an unique High-Energy Electron Linear Accelerator (10 MV) for radiant treatments which require higher doses in the surface levels of tissue. It is analyzed the interposition of acrylic degraders (spoilers) in the beam, especially for opposed and parallel fields in the cases of head and neck. It was analyzed the possible combinations of the following parameters: 1) Field sizes defined at isocenter (100 cm) 6 x 6 cm2, 8 x 8 cm2 and 10 x 10 cm2 ; 2) Surface-spoiler distance (DSS) of 4, 7 and 10 cm; 3) Spoilers with different thickness 1.1 and 1.5 cm. It was observed a displacement of the maximum dose toward the surface, and an increase in the percentile doses in the build-up zone when the spoiler is nearing and/or increasing its thickness. It is verified that the use of spoilers, support the symmetry and plane of the beam inside of the clinically acceptable margins. When the results obtained are analyzed then it is proposed as a calculation method to incorporate an attenuation factor. (Author)

  19. Development of high intensity linear accelerator for heavy ion inertial fusion driver

    International Nuclear Information System (INIS)

    In order to verify the direct plasma injection scheme (DPIS), an acceleration test was carried out in 2001 using a radio frequency quadrupole (RFQ) heavy ion linear accelerator (linac) and a CO2-laser ion source (LIS) (Okamura et al., 2002) [1]. The accelerated carbon beam was observed successfully and the obtained current was 9.22 mA for C4+. To confirm the capability of the DPIS, we succeeded in accelerating 60 mA carbon ions with the DPIS in 2004 (Okamura et al., 2004; Kashiwagi and Hattori, 2004) [2,3]. We have studied a multi-beam type RFQ with an interdigital-H (IH) cavity that has a power-efficient structure in the low energy region. We designed and manufactured a two-beam type RFQ linac as a prototype for the multi-beam type linac; the beam acceleration test of carbon beams showed that it successfully accelerated from 5 keV/u up to 60 keV/u with an output current of 108 mA (2×54 mA/channel) (Ishibashi et al., 2011) [4]. We believe that the acceleration techniques of DPIS and the multi-beam type IH-RFQ linac are technical breakthroughs for heavy-ion inertial confinement fusion (HIF). The conceptual design of the RF linac with these techniques for HIF is studied. New accelerator-systems using these techniques for the HIF basic experiment are being designed to accelerate 400 mA carbon ions using four-beam type IH-RFQ linacs with DPIS. A model with a four-beam acceleration cavity was designed and manufactured to establish the proof of principle (PoP) of the accelerator

  20. High resolution electron scattering facility at the Darmstadt linear accelerator (DALINAC). Pt. 3

    International Nuclear Information System (INIS)

    The multichannel detector system of the energy-loss electron scattering facility at the Darmstadt linear accelerator is described. The system consists of 36 overlapping plastic scintillators backed up by a large Cherenkov counter. Fast logic circuitry (300 MHz) is used to form a pattern of coincidence and antocoincidence bins definig 69 momentum channels. (orig.)

  1. On an inertial observer's interpretation of the detection of radiation by linearly accelerated particle detectors

    International Nuclear Information System (INIS)

    The detection of radiation by linearly accelerated particle detectors is discussed from the point of view of an inertial observer. An alternative interpretation to that of Unruh is presented. It is argued that the main physical effect is the emission of negative energy (as compared with Minkowski space) by the detector. This is shown to be the only important effect for 'macroscopic' detectors. (author)

  2. Investigation of linear accelerator pulse delivery using fast organic scintillator measurements

    DEFF Research Database (Denmark)

    Beierholm, Anders Ravnsborg; Andersen, Claus Erik; Lindvold, Lars René;

    2010-01-01

    Fiber-coupled organic plastic scintillators present an attractive method for time-resolved dose measurements during radiotherapy. Most organic scintillators exhibit a fast response, making it possible to use them to measure individual high-energy X-ray pulses from a medical linear accelerator. Th...

  3. Proceedings of the 1977 linear accelerator meeting in Japan, Tsukuba, November 30 - December 1, 1977

    International Nuclear Information System (INIS)

    Linear accelerators are now diversifying in usage, including the fields beyond nuclei and elementary particles. In the meeting, reflecting these recent developments, the following were discussed and report made are presented: beam blow-up, beam loading and bunched-beam structure, and single bunches occurrence and measurement. (Mori, K.)

  4. Promotion of high-quality treatment and uninterrupted service of radiation therapy linear accelerators

    International Nuclear Information System (INIS)

    The experience of operation of radiotherapy complex at Donetsk Antitumor Center showed that a number of calibration and dosimetry tests were an inevitable part of high-quality radiation treatment and timely prevention of inconsiderable disorders in the work of linear accelerators, therefore the engineering service of this equipment should consist of various specialists.

  5. Monte Carlo estimation of photoneutrons spectra and dose equivalent around an 18 MV medical linear accelerator

    Science.gov (United States)

    Alem-Bezoubiri, A.; Bezoubiri, F.; Badreddine, A.; Mazrou, H.; Lounis-Mokrani, Z.

    2014-04-01

    A fully detailed Monte Carlo geometrical model of an 18 MV Varian Clinac 2100C medical linear accelerator, lodged at Blida Anti-Cancer Centre in Algeria, was developed during this study to estimate the photoneutrons spectra and doses at the patient table in a radiotherapy treatment room, for radiation protection purposes.

  6. Stanford Linear Accelerator Center selects Verity Ultraseek for public and internal Web Sites

    CERN Multimedia

    2004-01-01

    Verity Inc., a provider of enterprise software has announced the latest version of its powerful, downloadable Verity(R) Ultraseek(R) enterprise search engine is being used by the Stanford Linear Accelerator Center, a research facility funded by the U.S. Department of Energy and operated by Stanford University (1/2 page).

  7. A portable 10-MeV electron linear accelerator as a neutron camera

    Energy Technology Data Exchange (ETDEWEB)

    Morgado, R.E.

    1989-05-01

    We present the results of a literature search into the present state-of-the-art techniques in producing, moderating, collimating, and imaging thermal neutrons, with an emphasis on radiographic diagnosis. The portable linear accelerator source we describe compares favorably with commercially available laboratory facilities for neutron production, while surpassing existing sources in portability. 16 refs., 10 figs., 4 tabs.

  8. A portable 10-MeV electron linear accelerator as a neutron camera

    International Nuclear Information System (INIS)

    We present the results of a literature search into the present state-of-the-art techniques in producing, moderating, collimating, and imaging thermal neutrons, with an emphasis on radiographic diagnosis. The portable linear accelerator source we describe compares favorably with commercially available laboratory facilities for neutron production, while surpassing existing sources in portability. 16 refs., 10 figs., 4 tabs

  9. Radiosurgery with a linear accelerator in cerebral arteriovenous malformations Radiocirurgia com acelerador linear em malformações arteriovenosas cerebrais

    Directory of Open Access Journals (Sweden)

    Sérgio Carlos Barros Esteves

    2008-04-01

    Full Text Available OBJECTIVE: To evaluate results achieved with radiosurgery and complications of the procedure when treating arteriovenous malformations with linear accelerator. METHODS: This retrospective study was conducted between October 1993 and December 1996. Sixty-one patients with arteriovenous malformations were treated with radiosurgery utilizing a 6MV energy linear accelerator. Ages of the 32 female and 29 male patients ranged from 6 to 54 years (mean: 28.3 years. The most frequent initial symptom was cephalea (45.9%, followed by neurological deficit (36.1%. Cerebral hemorrhage diagnosed by image was observed in 35 patients (57.3%. Most arteriovenous malformations (67.2% were graded Spetzler III and IV. Venous stenosis (21.3% and aneurysm (13.1% were the most frequent angioarchitecture changes. The dose administered varied from 12 to 27.5Gy in the periphery of the lesion. RESULTS: Out of twenty-eight patients that underwent conclusive angiography control, complete obliteration was achieved in 18 (72% and treatment failed in 7 (absence of occlusion with more than 3 years of follow-up. Four were submitted to a second radiosurgery, and one of these has shown obliteration after 18 months of follow-up. DISCUSSION: Several factors were analyzed regarding the occlusion rate (gender, age, volume, localization, Spetzler, flow, embolization, total of isocenters, prescribed dose and chosen isodose and complications (total of isocenters, localization, volume, maximum dose, prescribed dose and chosen isodose. Analyzed variables showed no statistical significance for obliteration of the vessel, as well as for treatment complications. The largest diameter of the arteriovenous malformation, its volume and the dose administered did not influence time of obliteration. CONCLUSION: Radiosurgery is effective in the treatment of arteriovenous malformations and can be an alternative for patients with clinical contraindication or with lesions in eloquent areas. In the studied

  10. The neutron dose equivalent around high energy medical electron linear accelerators

    Directory of Open Access Journals (Sweden)

    Poje Marina

    2014-01-01

    Full Text Available The measurement of neutron dose equivalent was made in four dual energy linear accelerator rooms. Two of the rooms were reconstructed after decommissioning of 60Co units, so the main limitation was the space. The measurements were performed by a nuclear track etched detectors LR-115 associated with the converter (radiator that consist of 10B and with the active neutron detector Thermo BIOREM FHT 742. The detectors were set at several locations to evaluate the neutron ambient dose equivalent and/or neutron dose rate to which medical personnel could be exposed. Also, the neutron dose dependence on collimator aperture was analyzed. The obtained neutron dose rates outside the accelerator rooms were several times smaller than the neutron dose rates inside the accelerator rooms. Nevertheless, the measured neutron dose equivalent was not negligible from the aspect of the personal dosimetry with almost 2 mSv a year per person in the areas occupied by staff (conservative estimation. In rooms with 15 MV accelerators, the neutron exposure to the personnel was significantly lower than in the rooms having 18 MV accelerators installed. It was even more pronounced in the room reconstructed after the 60Co decommissioning. This study confirms that shielding from the neutron radiation should be considered when building vaults for high energy linear accelerators, especially when the space constraints exist.

  11. A Concept of Plasma Wake Field Acceleration Linear Collider (PWFA-LC)

    Energy Technology Data Exchange (ETDEWEB)

    Seryi, Andrei; Hogan, Mark; Pei, Shilun; Raubenheimer, Tor; Tenenbaum, Peter; /SLAC; Katsouleas, Tom; /Duke U.; Huang, Chengkun; Joshi, Chan; Mori, Warren; /UCLA; Muggli, Patric; /Southern California U.

    2009-10-30

    Plasma Wake-Field Acceleration (PWFA) has demonstrated acceleration gradients above 50 GeV/m. Simulations have shown drive/witness bunch configurations that yield small energy spreads in the accelerated witness bunch and high energy transfer efficiency from the drive bunch to the witness bunch, ranging from 30% for a Gaussian drive bunch to 95% for a shaped longitudinal profile. These results open the opportunity for a linear collider that could be compact, efficient and more cost effective that the present microwave technologies. A concept of a PWFA-based Linear Collider (PWFA-LC) has been developed and is described in this paper. The drive beam generation and distribution, requirements on the plasma cells, and optimization of the interaction region parameters are described in detail. The R&D steps needed for further development of the concept are also outlined.

  12. Development of a 10 MW, 91 GHz Gyroklystron for W-Band Linear Accelerators

    Science.gov (United States)

    Nielson, Jeff; Ives, Lawrence; Lawson, Wes; Arjona, Melany

    1999-11-01

    An international effort is underway to design advanced linear electron-positron colliders with mass energies beyond 1 TeV. High power RF sources are required to drive accelerators operating at frequencies as high as W-Band. Calabazas Creek Research, Inc. is funded by the U.S. Department of Energy to design a 10 MW, second harmonic, gyroklystron at 91 GHz. The program is coordinated with W-Band accelerator research at the Stanford Linear Accelerator Center. The goal is to achieve an electronic efficiency of 45presentation will describe the proposed electron gun, three cavity RF circuit, magnetic circuit, and input and output couplers. Current simulation results will be presented and design tradeoffs will be discussed.

  13. Proceedings of the 18. international linear accelerator conference (Linac96). V.1

    International Nuclear Information System (INIS)

    These Proceedings cover the whole field of linear accelerators, from its original and continuing role in particle physics research to the wide range of applications found today in many other disciplines and technologies. The contributions were deliberately spread among the different conference sessions in order to maintain a broad interest. The topics covered include: the design, construction and control of linear accelerators and the associated technology; dedicated test facilities, injection, wakefields, bunching, halo, dynamics, radio-frequency (RF), electron and ion accelerators, (laser) ion sources; active alignment, beam steering and spot size; simulation, monitoring and diagnostics; a description of the performance and current status of many machines, including proposed ones such as CLIC, the NLC and TESLA; applications to medical diagnosis and radiotherapy; use in the treatment and sterilisation of materials (including food) and in the reprocessing of radioactive waste; use as potential suppliers of energy. (author)

  14. Use of electron linear accelerators in medical radiation therapy: physical characteristics. Overview report No. 1

    Energy Technology Data Exchange (ETDEWEB)

    1976-02-01

    This report presents an overview of the physical characteristics of electron linear accelerators used in medical radiation therapy. Particular attention is given to those physical characteristics and performance parameters that are related to delivery of a useful, properly controlled prescription dose of radiation to the patient or to delivery of a potentially harmful dose of radiation to the patient, machine operators, or others in the vicinity of the accelerator. The purpose of the study, of which this report is a part, was to provide a data base which will assist the Bureau of Radiological Health in evaluating the need for a performance standard for medical linear accelerators and the priority which should be assigned to such a standard should one be required. (auth)

  15. Phase control and intra-pulse phase compensation of the Advanced Photon Source (APS) linear accelerator

    International Nuclear Information System (INIS)

    Rf power for the APS linear accelerator is provided by five klystrons, each of which feeds one linac ''sector,'' containing accelerating structures and SLED cavities. A VXI-based subsystem measures the phase of each sector of the linac with respect to a thermally stabilized reference line. The resulting information is used to control a linearized varactor phase shifter. Error correction is done by software, using operator-controllable parameters. A second phase shifter provides an intra-pulse correction to the phase of the klystron drive pulse. When the intra-pulse correction is applied, the resulting phase is flat to within 0.5 degrees after 2.5 μsec. A second correction, made after the PSK trigger to the SLED and during the filling of the accelerating structures, resulted in an energy gain of 5 MeV from a single sector

  16. Non-linear model of particle acceleration at colliding shock flows

    CERN Document Server

    Bykov, A M; Osipov, S M

    2012-01-01

    Powerful stellar winds and supernova explosions with intense energy release in the form of strong shock waves can convert a sizeable part of the kinetic energy release into energetic particles. The starforming regions are argued as a favorable site of energetic particle acceleration and could be efficient sources of nonthermal emission. We present here a non-linear time-dependent model of particle acceleration in the vicinity of two closely approaching fast magnetohydrodynamic (MHD) shocks. Such MHD flows are expected to occur in rich young stellar cluster where a supernova is exploding in the vicinity of a strong stellar wind of a nearby massive star. We find that the spectrum of the high energy particles accelerated at the stage of two closely approaching shocks can be harder than that formed at a forward shock of an isolated supernova remnant. The presented method can be applied to model particle acceleration in a variety of systems with colliding MHD flows.

  17. Beam diagnostic of transverse geometric macrostructure errors for high energy part of linear ion accelerators

    International Nuclear Information System (INIS)

    The geometric transverse mismatching between the supports on which the elements of accelerating and trans-verse focusing structure are placed for high energy part of the linear accelerators for the ions with small mass, for example for protons or negative hydrogen ions, may lead to the particle loses of an accelerated beam or to the significant amplitudes for the beam center oscillations. The proposed method, in which it was supposed knowledge about the transverse geometric errors between the neighbour supports and application of the correction elements at the beginning of an accelerator part under investigation, permits to minimize amplitude of the transverse beam center oscillations. That leads to the reduction of possible beam loses and improvement a quality of the beam dynamics.

  18. Fast and dynamic generation of linear octrees for geological bodies under hardware acceleration

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In the application of 3D Geoscience Modeling,we often need to generate the volumetric representations of geological bodies from their surface representations.Linear octree,as an efficient and easily operated volumetric model,is widely used in 3D Geoscience Modeling.This paper proposes an algorithm for fast and dynamic generation of linear octrees of geological bodies from their surface models under hardware acceleration.The Z-buffers are used to determine the attributes of octants and voxels in a fast way,and a divide-and-conquer strategy is adopted.A stack structure is exploited to record the subdivision,which allows generating linear octrees dynamically.The algorithm avoids large-scale sorting process and bypasses the compression in linear octrees generation.Experimental results indicate its high efficiency in generating linear octrees for large-scale geologic bodies.

  19. Two-dimensional spatiotemporal coding of linear acceleration in vestibular nuclei neurons

    Science.gov (United States)

    Angelaki, D. E.; Bush, G. A.; Perachio, A. A.

    1993-01-01

    Response properties of vertical (VC) and horizontal (HC) canal/otolith-convergent vestibular nuclei neurons were studied in decerebrate rats during stimulation with sinusoidal linear accelerations (0.2-1.4 Hz) along different directions in the head horizontal plane. A novel characteristic of the majority of tested neurons was the nonzero response often elicited during stimulation along the "null" direction (i.e., the direction perpendicular to the maximum sensitivity vector, Smax). The tuning ratio (Smin gain/Smax gain), a measure of the two-dimensional spatial sensitivity, depended on stimulus frequency. For most vestibular nuclei neurons, the tuning ratio was small at the lowest stimulus frequencies and progressively increased with frequency. Specifically, HC neurons were characterized by a flat Smax gain and an approximately 10-fold increase of Smin gain per frequency decade. Thus, these neurons encode linear acceleration when stimulated along their maximum sensitivity direction, and the rate of change of linear acceleration (jerk) when stimulated along their minimum sensitivity direction. While the Smax vectors were distributed throughout the horizontal plane, the Smin vectors were concentrated mainly ipsilaterally with respect to head acceleration and clustered around the naso-occipital head axis. The properties of VC neurons were distinctly different from those of HC cells. The majority of VC cells showed decreasing Smax gains and small, relatively flat, Smin gains as a function of frequency. The Smax vectors were distributed ipsilaterally relative to the induced (apparent) head tilt. In type I anterior or posterior VC neurons, Smax vectors were clustered around the projection of the respective ipsilateral canal plane onto the horizontal head plane. These distinct spatial and temporal properties of HC and VC neurons during linear acceleration are compatible with the spatiotemporal organization of the horizontal and the vertical/torsional ocular responses

  20. Development and test of an accelerating cavity shape for a superconducting linear collider

    International Nuclear Information System (INIS)

    In order to use superconducting RF accelerating structures in the construction of a linear collider certain criteria must be addressed. Foremost of these criteria is the high accelerating gradient. This requirement might be more accurately expressed as the accelerating gradient per unit cost. The authors see therefore that cost/unit length is also a primary criteria. The cavity must be designed so that input power can be coupled in and higher order mode (HOM) power may be coupled out to the degree required by beam stability considerations. At this time in the development of superconducting RF accelerating cavities, the accelerating gradient is limited by two phenomena, electron field emission and thermal breakdown. The first of these makes it imperative to choose a cell shape that minimizes Epk/Eacc and the second phenomena to minimize Hpk/Eacc (the ratio of the peak surface fields to the accelerating gradient). As field emission is the dominant gradient limitation, there is considerable premium in lowering Epk/Eacc. The cell to cell coupling (K) is also effected by the shape. This is true of the coupling of the HOM's as well as the fundamental TM010 mode. Because of this, the number of coupled cells comprising an accelerating unit is limited. A larger number of cells/module helps reduce the structure cost by reducing the number of couplers as well as by improving the filling factor for the machine. An effort is made here to increase the number of cells per module to 10

  1. Rf System For The Industrial Linear Electron Accelerator At Kaeri (daejeon, Korea)

    CERN Document Server

    Arbuzov, V S; Evtushenko, Yu A; Gorniker, E I; Kenjebulatov, E K; Kondakov, A A; Krutikhin, S A; Kurkin, G Ya; Motygin, S V; Osipov, V N; Petrov, V M; Pilan, Andrey M; Popov, A R; Shteinke, A M; Tribendis, A G

    2004-01-01

    Budker Institute of Nuclear Physics has developed and produced RF generators, feeder lines and a control system for an industrial linear electron accelerator at Korean Atomic Energy Research Institute (KAERI, Daejeon, Korea). The accelerator is based on two superconducting RF cavities produced by CERN. Design energy of the accelerator is 10 MeV and design beam current is 10 mA. A 2 MeV injector for the accelerator was made by BINP earlier. Two-channel RF system of the accelerator operates at the frequency of 352 MHz in CW mode. Each channel has two-stage tetrode amplifier with output power of 50 kW, 100 W transistor preamplifier and the control system. Both tetrode stages have identical design. TH571B tetrode tubes produced by THALES (France) are used. Output power of 45 kW per channel was reached in an equivalent resistive load. Now BINP continues development of the accelerator. The energy of 11 MeV and the beam current of 1.9 mA were achieved. The amplitude of accelerating voltage was 4.5 MV in each cavity,...

  2. Wakefield Damping in a Pair of X-Band Accelerators for Linear Colliders

    International Nuclear Information System (INIS)

    We consider means to damp the wake-field left behind ultra-relativistic charges. In particular, we focus on a pair of travelling wave accelerators operating at an X-band frequency of 11.424 GHz. In order to maximize the efficiency of acceleration, in the context of a linear collider, multiple bunches of charged particles are accelerated within a given pulse of the electromagnetic field. The wake-field left behind successive bunches, if left unchecked, can seriously disturb the progress of trailing bunches and can lead to an appreciable dilution in the emittance of the beam. We report on a method to minimize the influence of the wake-field on trailing bunches. This method entails detuning the characteristic mode frequencies which make-up the electromagnetic field, damping the wake-field, and interleaving the frequencies of adjacent accelerating structures. Theoretical predictions of the wake-field and modes, based on a circuit model, are compared with experimental measurements of the wake-field conducted within the ASSET facility at SLAC. Very good agreement is obtained between theory and experiment and this allows us to have some confidence in designing the damping of wake-fields in a future linear collider consisting of several thousand of these accelerating structures

  3. Development of linear proton accelerators with the high average beam power

    CERN Document Server

    Bomko, V A; Egorov, A M

    2001-01-01

    Review of the current situation in the development of powerful linear proton accelerators carried out in many countries is given. The purpose of their creation is solving problems of safe and efficient nuclear energetics on a basis of the accelerator-reactor complex. In this case a proton beam with the energy up to 1 GeV, the average current of 30 mA is required. At the same time there is a needed in more powerful beams,for example, for production of tritium and transmutation of nuclear waste products. The creation of accelerators of such a power will be followed by the construction of linear accelerators of 1 GeV but with a more moderate beam current. They are intended for investigation of many aspects of neutron physics and neutron engineering. Problems in the creation of efficient constructions for the basic and auxiliary equipment, the reliability of the systems, and minimization of the beam losses in the process of acceleration will be solved.

  4. Stereotactic body radiation therapy (SBRT) for lung malignancies: preliminary toxicity results using a flattening filter-free linear accelerator operating at 2400 monitor units per minute

    OpenAIRE

    Prendergast, Brendan M; Dobelbower, Michael C; Bonner, James A.; Popple, Richard A.; Baden, Craig J; Minnich, Douglas J.; Cerfolio, Robert J.; Spencer, Sharon A; Fiveash, John B.

    2013-01-01

    Background Flattening filter-free (FFF) linear accelerators (linacs) are capable of delivering dose rates more than 4-times higher than conventional linacs during SBRT treatments, causing some to speculate whether the higher dose rate leads to increased toxicity owing to radiobiological dose rate effects. Despite wide clinical use of this emerging technology, clinical toxicity data for FFF SBRT are lacking. In this retrospective study, we report the acute and late toxicities observed in our l...

  5. Linear vs. nonlinear acceleration in plasma turbulence. II. Hall–finite-Larmor-radius magnetohydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Sanjoy [Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland 20723 (United States); Parashar, Tulasi N. [University of Delaware, Newark, Delaware 19716 (United States)

    2015-04-15

    The local k-space ratio of linear and nonlinear accelerations associated with a variety of initial conditions undergoing steady relaxation is investigated for the Hall–finite-Larmor-radius magnetohydrodynamics (MHD) system in the presence of a mean magnetic field. Building on a related study (Paper I) where it was shown that discrepancies exist between describing the global and local characterizations of the pure MHD system with mean magnetic field, we find regions of the Fourier space that are consistently dominated by linear acceleration and other regions that are consistently dominated by nonlinear acceleration, independent of the overall system's description as linear, weakly nonlinear, or turbulent. In general, dynamics within a certain angular range of the mean magnetic field direction are predominantly linear, while dynamics adjacent the Hall scales along the field-parallel direction and dynamics adjacent the finite Larmor radius scales in the field-perpendicular direction can become strongly nonlinear. The nonlinear influences are particularly significant as the plasma beta increases from unity to higher values.

  6. Linear vs. nonlinear acceleration in plasma turbulence. II. Hall–finite-Larmor-radius magnetohydrodynamics

    International Nuclear Information System (INIS)

    The local k-space ratio of linear and nonlinear accelerations associated with a variety of initial conditions undergoing steady relaxation is investigated for the Hall–finite-Larmor-radius magnetohydrodynamics (MHD) system in the presence of a mean magnetic field. Building on a related study (Paper I) where it was shown that discrepancies exist between describing the global and local characterizations of the pure MHD system with mean magnetic field, we find regions of the Fourier space that are consistently dominated by linear acceleration and other regions that are consistently dominated by nonlinear acceleration, independent of the overall system's description as linear, weakly nonlinear, or turbulent. In general, dynamics within a certain angular range of the mean magnetic field direction are predominantly linear, while dynamics adjacent the Hall scales along the field-parallel direction and dynamics adjacent the finite Larmor radius scales in the field-perpendicular direction can become strongly nonlinear. The nonlinear influences are particularly significant as the plasma beta increases from unity to higher values

  7. Beamline considerations for a compact, high current, high power linear RF electron accelerator

    International Nuclear Information System (INIS)

    A design for a compact, high current, high power linear electron accelerator using an rf power source is investigated. It consists of adjacent cavities into which rf power is injected and through which electron pulses pass. The source is assumed to be capable of delivering sufficient rf power to the desired location at the proper phase. Beamline issues such as cavity loading, energy extraction, longitudinal and transverse pulse focusing, and beam breakup are considered. A device which, given the required source, can deliver beam parameters comparable to existing induction accelerators but which is more than an order of magnitude smaller appears feasible

  8. A model for the determination of the nominal potential for a linear accelerator

    International Nuclear Information System (INIS)

    The objective of the present work is to find a physical mathematical model based on the reason of the dose percentages at 10 and 20 cm depth, at 100 cm DFS and a 10 x 10 cm2 field. It was utilized literature data of new manufactured accelerators and those are in use in hospitals, which allow to prove the model under different conditions. Our objective consists only to obtain a model that verifies the nominal potential for a linear accelerator, but without pretending that such a model to be used to calculate any one factor to determination of absorbed dose. (Author)

  9. Modulator for LUEK-20 linear induction electron-ion ring accelerator

    International Nuclear Information System (INIS)

    A high-power modulator - generator of accelerating-voltage pulses - for the LUEK-20 linear induction electron-ion ring accelerator is described. The modulator has an output of 50 kV into a 0.5-Ω load, a load current of ∼ 100 kA, and a voltage-pulse duration at the load of 70-80 nsec. The modulator employs nonlinear power-amplifier circuits with time compression of the electromagnetic energy. The results of adjustment of one of the parallel branches of the modulator are presented

  10. Determination of Personal Dose Equivalent at INFLPR 7 MeV Linear Accelerator

    International Nuclear Information System (INIS)

    This paper presents the measurements of the personal dose equivalent performed in INFLPR - 7 MeV Linear Accelerator building by means of the secondary standard chamber Hp (10), T34035 type. The conventional true value of the personal dose equivalent Hp (10, R, a), in a slab phantom for the radiation quality R, at a angle of incidence between the radiation beam and the normal to the chamber front face, is directly proportional with the electric charge measured by the chamber, QR, for the radiation quality S and the angle incidence a = 00. The measurements were made for the accelerator electron operation mode

  11. The modulator of the LUEhK-20 linear induction electron ring accelerator

    International Nuclear Information System (INIS)

    The powerful modulator - the accelerating voltage pulse generator of the linear induction electron ring accelerator LUEhK-20 is described. The modulator parameters are: output voltage on the load Rsub(H)=0.5 Ohm is equal to 50 kV; current in the load is approximately 100 kA; duration of the voltage pulses on the load is 70-80 ns. The modulator is designed with application of the nonlinear circuits of power amplification by means of electromagnetic energy compression in time. The adjustment of one of the parallel modulator circuit branches is described

  12. Effects of rf breakdown on the beam in the Compact Linear Collider prototype accelerator structure

    OpenAIRE

    Palaia, Andrea; Jacewicz, Marek; Ruber, Roger; Ziemann, Volker; Farabolini, Wilfrid

    2013-01-01

    Understanding the effects of rf breakdown in high-gradient accelerator structures on the acceleratedbeam is an extremely relevant aspect in the development of the Compact Linear Collider (CLIC) andis one of the main issues addressed at the Two-beam Test Stand at the CLIC Test Facility 3 at CERN.During a rf breakdown high currents are generated causing parasitic magnetic fields that interact withthe accelerated beam affecting its orbit. The beam energy is also affected because the power is part...

  13. Installation for electron beam sterilization based on 3 MeV linear accelerator

    International Nuclear Information System (INIS)

    Characteristics and short description of the sterilizing installation with the energy 3 MeV of accelerated electrons and power 2.5 kW in beam are presented. New compact radiation installation for the sterilization of food, medical items, post packages consists of the linear accelerator UEhl-3-2.5 with scanning device and irradiation chamber with equipment for transportation of irradiated objects. Feature of the installation consists of the presence of local radiation shield that lowering radiation level at the distance of 100 mm from outside surface of the installation to 1 μSv/h

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

    International Nuclear Information System (INIS)

    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

  15. Quadrupole lenses with permanent magnets for drift tubes of ion linear accelerators

    International Nuclear Information System (INIS)

    With the purpose of constructing a strong-focusing channel of permanent-magnet quadrupoles for an ion linear accelerator three experimental lenses have been designed and manufactured for use in drift tubes of a two-frequency proton linear accelerator. The poles of the first lens are made of the ''Magnico'' alloy; those of the second and the third lenses - of the YUND35T5BA alloy. The pole tips and yokes are of Armco. The characteristics of the lens with gradients of 29 and 50 T/m and aperture diameter of 2 cm are given. The gradient is changed by less than 0.5% in the aperture as the temperature is varied from 10 to 30 deg C

  16. Investigation of linear accelerator pulse delivery using fast organic scintillator measurements

    Energy Technology Data Exchange (ETDEWEB)

    Beierholm, A.R., E-mail: anders.beierholm@risoe.d [Radiation Research Department, Riso National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark); Andersen, C.E.; Lindvold, L.R. [Radiation Research Department, Riso National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark); Aznar, M.C. [Department of Radiation Oncology, Copenhagen University Hospital, DK-2100 Copenhagen (Denmark)

    2010-03-15

    Fiber-coupled organic plastic scintillators present an attractive method for time-resolved dose measurements during radiotherapy. Most organic scintillators exhibit a fast response, making it possible to use them to measure individual high-energy X-ray pulses from a medical linear accelerator. This can be used in complex treatment procedures such as gated intensity-modulated radiotherapy (IMRT), where the advantage of dose rate measurements of high temporal resolution is highly emphasized. We report on development of a fast data acquisition scintillator-based system as well as measurements performed on Varian medical linear accelerators, delivering 6 MV X-ray beams. The dose delivery per radiation pulse was found to agree with expectations within roughly 1%, although minor discrepancies and transients were evident in the measurements.

  17. Processing and evaluation of linear accelerator-produced 99Mo/99mTc in Canada

    International Nuclear Information System (INIS)

    We are developing electron linear accelerator 100Mo(γ,n)99Mo technology as a replacement to nuclear reactor 235U(n,f)99Mo production. We report irradiation of natural molybdenum disks (25 MeV, 10 kW) and 100Mo-enriched disks (35 MeV, 2 kW), their dissolution and the extraction of 99mTc-pertechnetate. Up to 6.2 GBq 99Mo was produced, solvent extraction was performed at >90 % yields of 99mTc, and quality control showed that a product with high radionuclidic and radiochemical purity could be obtained. Irradiated natural molybdenum products showed more impurities (91mNb, 92mNb, 95mNb and 95Nb) than enriched target material. Linear accelerator technology is feasible for production of quality 99Mo/99mTc, particularly when paired with 100Mo-enriched targets. (author)

  18. Proceedings of the conference on computer codes and the linear accelerator community

    International Nuclear Information System (INIS)

    The conference whose proceedings you are reading was envisioned as the second in a series, the first having been held in San Diego in January 1988. The intended participants were those people who are actively involved in writing and applying computer codes for the solution of problems related to the design and construction of linear accelerators. The first conference reviewed many of the codes both extant and under development. This second conference provided an opportunity to update the status of those codes, and to provide a forum in which emerging new 3D codes could be described and discussed. The afternoon poster session on the second day of the conference provided an opportunity for extended discussion. All in all, this conference was felt to be quite a useful interchange of ideas and developments in the field of 3D calculations, parallel computation, higher-order optics calculations, and code documentation and maintenance for the linear accelerator community. A third conference is planned

  19. Object-Oriented Parallel Particle-in-Cell Code for Beam Dynamics Simulation in Linear Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, J.; Ryne, R.D.; Habib, S.; Decky, V.

    1999-11-13

    In this paper, we present an object-oriented three-dimensional parallel particle-in-cell code for beam dynamics simulation in linear accelerators. A two-dimensional parallel domain decomposition approach is employed within a message passing programming paradigm along with a dynamic load balancing. Implementing object-oriented software design provides the code with better maintainability, reusability, and extensibility compared with conventional structure based code. This also helps to encapsulate the details of communications syntax. Performance tests on SGI/Cray T3E-900 and SGI Origin 2000 machines show good scalability of the object-oriented code. Some important features of this code also include employing symplectic integration with linear maps of external focusing elements and using z as the independent variable, typical in accelerators. A successful application was done to simulate beam transport through three superconducting sections in the APT linac design.

  20. Proceedings of the conference on computer codes and the linear accelerator community

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, R.K. (comp.)

    1990-07-01

    The conference whose proceedings you are reading was envisioned as the second in a series, the first having been held in San Diego in January 1988. The intended participants were those people who are actively involved in writing and applying computer codes for the solution of problems related to the design and construction of linear accelerators. The first conference reviewed many of the codes both extant and under development. This second conference provided an opportunity to update the status of those codes, and to provide a forum in which emerging new 3D codes could be described and discussed. The afternoon poster session on the second day of the conference provided an opportunity for extended discussion. All in all, this conference was felt to be quite a useful interchange of ideas and developments in the field of 3D calculations, parallel computation, higher-order optics calculations, and code documentation and maintenance for the linear accelerator community. A third conference is planned.

  1. Efficient SAT engines for concise logics: Accelerating proof search for zero-one linear constraint systems

    DEFF Research Database (Denmark)

    Fränzle, Martin; Herde, Christian

    We investigate the problem of generalizing acceleration techniques as found in recent satisfiability engines for conjunctive normal forms (CNFs) to linear constraint systems over the Booleans. The rationale behind this research is that rewriting the propositional formulae occurring in e.g. bounded...... model checking (BMC) [Biere, Cimatti,Zhu, 1999] to CNF requires a blowup in either the formula size (worst-case exponential) or in the number of propositional variables (linear, thus yielding a worst-case exponential blow-up of the search space). We demonstrate that acceleration techniques like....... Despite the more expressive input language, the performance of our prototype implementation comes surprisingly close to that of state-of-the-art CNF-SAT engines like ZChaff [Moskewicz e.a., 2001]. First experiments with bounded model-construction problems show that the overhead in the satisfiability...

  2. Nelson's syndrome: single centre experience using the linear accelerator (LINAC) for stereotactic radiosurgery and fractionated stereotactic radiotherapy.

    Science.gov (United States)

    Wilson, Peter J; Williams, Janet R; Smee, Robert I

    2014-09-01

    Nelson's syndrome is a unique clinical phenomenon of growth of a pituitary adenoma following bilateral adrenalectomies for the control of Cushing's disease. Primary management is surgical, with limited effective medical therapies available. We report our own institution's series of this pathology managed with radiation: prior to 1990, 12 patients were managed with conventional radiotherapy, and between 1990 and 2007, five patients underwent stereotactic radiosurgery (SRS) and two patients fractionated stereotactic radiotherapy (FSRT), both using the linear accelerator (LINAC). Tumour control was equivocal, with two of the five SRS patients having a reduction in tumour volume, one patient remaining unchanged, and two patients having an increase in volume. In the FSRT group, one patient had a decrease in tumour volume whilst the other had an increase in volume. Treatment related morbidity was low. Nelson's syndrome is a challenging clinical scenario, with a highly variable response to radiation in our series. PMID:24825407

  3. Experimental study on resonance relativistic SHF generators on the base of linear induction electron accelerator

    International Nuclear Information System (INIS)

    The results of studies on relativistic SHF-generators - orotron and gyrotron for obtaining data on the quality of a high-current electron beam shaped in the section of a linear induction accelerator are given. Axisymmetric resonators as sections of weak-irregular waveguides were used in both generators. Stable generation of short-wave radiation of 15-20 MW at the efficiency of 5-7% SHF pulse duration of 50 ns was obtained in the orotron at the wave length of 8.5 mm and current of 600 A. Stable generation of 7-10 MW SHF-radiation at the efficiency of 3-5% and pulse duration of 150 ns was observed in the gyrotron at the wave length of 12 mm. Under further acceleration in the following sections of the accelerator the electron beam may be used for obtaining radiation of shorter waves

  4. Control of linear accelerator noise in the Los Alamos free-electron laser (FEL)

    International Nuclear Information System (INIS)

    The Los Alamos FEL requires tight control of the amplitudes and phases of the fields in two linear accelerator tanks to obtain stable lasing. The accelerator control loops must establish constant, stable, repeatable amplitudes and phases of the rf fields and must have excellent bandwidth to control high-frequency noise components. A model of the feedback loops has been developed that agrees well with measurements and allows easy substitution of components and circuits, thus reducing breadboarding requirements. The model permits both frequency and time-domain analysis. This paper describes the accelerator control scheme and our model and discusses the control of noise in feedback loops, showing how low-frequency-noise components (errors) can be corrected, but high-frequency-noise components (errors) are actually amplified by the feedback circuit. Measurements of noise in both open- and closed-loop modes are shown and comparison is made with results from the model calculations

  5. ESS-Bilbao light-ion linear accelerator and neutron source: design and applications

    International Nuclear Information System (INIS)

    The baseline design for the ESS-Bilbao light-ion linear accelerator and neutron source has been completed and the normal conducting section of the linac is at present under construction. The machine has been designed to be compliant with ESS specifications following the international guidelines of such project as described in Ref. [1]. The new accelerator facility in Bilbao will serve as a base for support of activities on accelerator physics carried out in Spain and southern Europe in the frame of different ongoing international collaborations. Also, a number of applications have been envisaged in the new Bilbao facility for the outgoing light ion beams as well as from fast neutrons produced by low-energy neutron-capture targets, which are briefly described.

  6. Vacuum system of the linear accelerator of multicharged ions of 1 MeV per nucleon

    International Nuclear Information System (INIS)

    Described is a vacuum system of a linear accelerator of multicharged ions LUMZI of 1 MeV per nucleon. The system consists of a self-contained injector pumping-out systems, accelerator, and general forevacuum pumping-out system. For the main LUMZI pumping-out developed are oil-diffusion pumps, operating on a new working liquid (5F4E polyphenyl ester). Application of this liquid permitted to reduce limiting pressure and to decrease vapor transfer to the accelerator. Given are the scheme and general plan of the vacuum system with NMDO magnetodischarge pump for vacuum supply to non-working changes. The pump operates in an automatical regime without service staff

  7. Reduction of beam corkscrew motion on the ETAII linear induction accelerator

    International Nuclear Information System (INIS)

    The ETAII linear induction accelerator (6MeV, 3kA, 70ns ) is designed to drive a microwave free electron laser (FEL) and demonstrate the front end accelerator technology for a shorter wavelength FEL. Performance to date has been limited by beam corkscrew motion that is driven by energy sweep and misalignment of the solenoidal focusing magnets. Modifications to the pulse power distribution system and magnetic alignment are expected to reduce the radius of corkscrew motion from its present value of 1 cm to less than 1mm. The modifications have so far been carried out on the first 2.7 MeV (injector plus 20 accelerator cells) and experiments are beginning. In this paper the authors present calculations of central flux line alignment, beam corkscrew motion and beam brightness that are anticipated with the modified ETAII

  8. Diaphragm effects on the stability of an electron beam in an induction linear accelerator

    International Nuclear Information System (INIS)

    The effect of shielding of an electron beam electromagnetic field by a sequence of metallic diaphragms, used in induction linear accelerators for acceleration tube protection against charge landing, on the stability of transverse beam motion is considered. The coefficients are calculated of shielding of quasi-stationary electric and magnetic fields of a beam displaced relative to the accelerator axis. The values of longitudinal magnetic field strength necessary for coherent beam focusing are determined. The electron beam instability increment on an asymmetric hybrid wave in a decelerating structure formed by the sequence of diaphragms is found. It is shown that the destabilizing effect of the diaphragm can be weakened by increasing the ratio of the structure period to its radius

  9. Automating quality assurance of digital linear accelerators using a radioluminescent phosphor coated phantom and optical imaging

    Science.gov (United States)

    Jenkins, Cesare H.; Naczynski, Dominik J.; Yu, Shu-Jung S.; Yang, Yong; Xing, Lei

    2016-09-01

    Performing mechanical and geometric quality assurance (QA) tests for medical linear accelerators (LINAC) is a predominantly manual process that consumes significant time and resources. In order to alleviate this burden this study proposes a novel strategy to automate the process of performing these tests. The autonomous QA system consists of three parts: (1) a customized phantom coated with radioluminescent material; (2) an optical imaging system capable of visualizing the incidence of the radiation beam, light field or lasers on the phantom; and (3) software to process the captured signals. The radioluminescent phantom, which enables visualization of the radiation beam on the same surface as the light field and lasers, is placed on the couch and imaged while a predefined treatment plan is delivered from the LINAC. The captured images are then processed to self-calibrate the system and perform measurements for evaluating light field/radiation coincidence, jaw position indicators, cross-hair centering, treatment couch position indicators and localizing laser alignment. System accuracy is probed by intentionally introducing errors and by comparing with current clinical methods. The accuracy of self-calibration is evaluated by examining measurement repeatability under fixed and variable phantom setups. The integrated system was able to automatically collect, analyze and report the results for the mechanical alignment tests specified by TG-142. The average difference between introduced and measured errors was 0.13 mm. The system was shown to be consistent with current techniques. Measurement variability increased slightly from 0.1 mm to 0.2 mm when the phantom setup was varied, but no significant difference in the mean measurement value was detected. Total measurement time was less than 10 minutes for all tests as a result of automation. The system’s unique features of a phosphor-coated phantom and fully automated, operator independent self-calibration offer the

  10. Automating quality assurance of digital linear accelerators using a radioluminescent phosphor coated phantom and optical imaging.

    Science.gov (United States)

    Jenkins, Cesare H; Naczynski, Dominik J; Yu, Shu-Jung S; Yang, Yong; Xing, Lei

    2016-09-01

    Performing mechanical and geometric quality assurance (QA) tests for medical linear accelerators (LINAC) is a predominantly manual process that consumes significant time and resources. In order to alleviate this burden this study proposes a novel strategy to automate the process of performing these tests. The autonomous QA system consists of three parts: (1) a customized phantom coated with radioluminescent material; (2) an optical imaging system capable of visualizing the incidence of the radiation beam, light field or lasers on the phantom; and (3) software to process the captured signals. The radioluminescent phantom, which enables visualization of the radiation beam on the same surface as the light field and lasers, is placed on the couch and imaged while a predefined treatment plan is delivered from the LINAC. The captured images are then processed to self-calibrate the system and perform measurements for evaluating light field/radiation coincidence, jaw position indicators, cross-hair centering, treatment couch position indicators and localizing laser alignment. System accuracy is probed by intentionally introducing errors and by comparing with current clinical methods. The accuracy of self-calibration is evaluated by examining measurement repeatability under fixed and variable phantom setups. The integrated system was able to automatically collect, analyze and report the results for the mechanical alignment tests specified by TG-142. The average difference between introduced and measured errors was 0.13 mm. The system was shown to be consistent with current techniques. Measurement variability increased slightly from 0.1 mm to 0.2 mm when the phantom setup was varied, but no significant difference in the mean measurement value was detected. Total measurement time was less than 10 minutes for all tests as a result of automation. The system's unique features of a phosphor-coated phantom and fully automated, operator independent self-calibration offer the

  11. Cr-39 neutron track detectors for photo neutron studies from high energy medical linear accelerator

    International Nuclear Information System (INIS)

    Photo-neutron measurements with CR-39 (2.45 x 2.45 x 1.5 mm) films provided by Intercast Europe, Parma-Italy was carried at Regional Cancer Center-Trivandrum, Kerala. Measurements were taken from Varian Clinac-iX medical linear accelerator from 6 and 15 MV photon beams in clinical treatment modes. Films were etched using 6N NaOH solutions for 10 hours and track density was counted using Olympus microscopes (1000X). Readings are taken in conventional treatment mode and IMRT (Intensity Modulated Radiation Therapy) methods using the above energy. Background is measured in the same batch of film and average track density found negligible (0.8/cm2). Readings are taken at the field center and out of field of irradiated area. Outside neutron density have great influence in NTCP (Normal Tissue Complication Probability) concept. In 6 MV photon beam, 10x10 cm2 field defined using diaphragm have slightly higher neutron track density at field center (1.9/cm2) than MLC (Multi Leaf Collimator) sweeping (1.6/cm2) for the same deliverable dose. 15 MV treatment contributes considerable neutrons in and out of treatment fields. 5 cm out of 10x10 cm2 square field neutron track density averaged over film area is 56.4 (1/cm2) while the field center gives twice the neutron contribution (107.2/cm2). MLC sweeping field for 15 MV have highest contribution at center (175.5/cm2). All the irradiations are with same MU (244) for 200 cGy at 15 cm depth for 15 MV beam. (author)

  12. Photo neutron measurements using CR-39 films from high energy medical linear accelerator

    International Nuclear Information System (INIS)

    Photo-neutron measurements with CR-39 (2.45 x 2.45 x 1.5 mm) films provided by intercast Europe, Parma-Italy was carried at Regional Cancer Center-Trivandrum, Kerala. Measurements were taken from Varian Clinac-iX medical linear accelerator from 6 and 15 MV photon beams in clinical treatment modes. Films were etched using 6N NaOH solutions for 10 hours and track density was counted using Olympus microscopes (1000X). Readings are taken in conventional treatment mode and IMRT (Intensity modulated Radiation Therapy) methods using the above energy. Background is measured in the same batch of film and average track density found negligible (0.8/cm2). Readings are taken at the field center and out of field of irradiated area. Outside neutron density have great influence in NTCP (Normal Tissue Complication probability) concept. In 6MV photon beam, 10 x 10 cm2 field defined using diaphragm have slightly higher neutron track density at field center (1.9/cm2) than MLC (Multi Leaf Collimator) sweeping (1.6/cm2) for the same deliverable dose. 15MV treatment tributes considerable neutrons in and out of treatment fields. 5cm out of 10 x 10 cm2 square field neutron track density averaged over film area is 56.4 (1/cm2) while the field center gives twice the neutron contribution (107.2/cm2). MLC sweeping field for 15MV have highest contribution at center (175.5/cm2). All the irradiations are with same MU (244) for 200 cGy at 15 cm depth for 15 MV beam. (author)

  13. Spatiotemporal processing of linear acceleration: primary afferent and central vestibular neuron responses

    Science.gov (United States)

    Angelaki, D. E.; Dickman, J. D.

    2000-01-01

    Spatiotemporal convergence and two-dimensional (2-D) neural tuning have been proposed as a major neural mechanism in the signal processing of linear acceleration. To examine this hypothesis, we studied the firing properties of primary otolith afferents and central otolith neurons that respond exclusively to horizontal linear accelerations of the head (0.16-10 Hz) in alert rhesus monkeys. Unlike primary afferents, the majority of central otolith neurons exhibited 2-D spatial tuning to linear acceleration. As a result, central otolith dynamics vary as a function of movement direction. During movement along the maximum sensitivity direction, the dynamics of all central otolith neurons differed significantly from those observed for the primary afferent population. Specifically at low frequencies (frequency. "Flat" neurons were characterized by relatively flat gains and constant phase lags (approximately 20-55 degrees ). A few neurons ("low-pass") were characterized by decreasing gain and phase as a function of frequency. The response dynamics of central otolith neurons suggest that the approximately 90 degrees phase lags observed at low frequencies are not the result of a neural integration but rather the effect of nonminimum phase behavior, which could arise at least partly through spatiotemporal convergence. Neither afferent nor central otolith neurons discriminated between gravitational and inertial components of linear acceleration. Thus response sensitivity was indistinguishable during 0.5-Hz pitch oscillations and fore-aft movements. The fact that otolith-only central neurons with "high-pass" filter properties exhibit semicircular canal-like dynamics during head tilts might have important consequences for the conclusions of previous studies of sensory convergence and sensorimotor transformations in central vestibular neurons.

  14. Evaluation of the effectiveness of packed red blood cell irradiation by a linear accelerator

    OpenAIRE

    Olivo, Ricardo Aparecido; da Silva, Marcus Vinícius; Garcia, Fernanda Bernadelli; Soares, Sheila; Rodrigues Junior, Virmondes; Moraes-Souza, Helio

    2015-01-01

    Irradiation of blood components with ionizing radiation generated by a specific device is recommended to prevent transfusion-associated graft-versus-host disease. However, a linear accelerator can also be used in the absence of such a device, which is the case of the blood bank facility studied herein. In order to evaluate the quality of the irradiated packed red blood cells, this study aimed to determine whether the procedure currently employed in the facility is effective in inhibiting the ...

  15. An overview of application and radiation safety aspects of linear accelerators in Brazilian industry

    International Nuclear Information System (INIS)

    This work presents a brief description of the situation of Brazilian Regulatory Authority about safety control on Industrial Linear Accelerators Installations. It shows the national regulatory infrastructure responsible for radiation safety inspections, the regulation infrastructure, the national inventory of industrial installations, the national system of inspection and enforcement and the national system for qualifying the radiation protection officer. Some results of regulatory safety inspections are also showed in this work. (author)

  16. The neutron dose equivalent around high energy medical electron linear accelerators

    OpenAIRE

    Poje Marina; Ivković Ana; Jurković Slaven; Žauhar Gordana; Vuković Branko; Radolić Vanja; Miklavčić Igor; Kaliman Zoran; Planinić Josip; Brkić Hrvoje; Faj Dario

    2014-01-01

    The measurement of neutron dose equivalent was made in four dual energy linear accelerator rooms. Two of the rooms were reconstructed after decommissioning of 60Co units, so the main limitation was the space. The measurements were performed by a nuclear track etched detectors LR-115 associated with the converter (radiator) that consist of 10B and with the active neutron detector Thermo BIOREM FHT 742. The detectors were set at several locations to evaluate ...

  17. Linear accelerator-based stereotactic radiosurgery in 140 brain metastases from malignant melanoma

    OpenAIRE

    Hauswald, Henrik; Stenke, Alina; Debus, Jürgen; Combs, Stephanie E

    2015-01-01

    Background: To retrospectively access outcome and prognostic parameters of linear accelerator-based stereotactic radiosurgery in brain metastases from malignant melanoma. Methods: Between 1990 and 2011 140 brain metastases in 84 patients with malignant melanoma (median age 56 years) were treated with stereotactic radiosurgery. At initial stereotactic radiosurgery 48 % of patients showed extracerebral control. The median count of brain metastases in a single patient was 1, the median diamete...

  18. Image-guided linear accelerator-based spinal radiosurgery for hemangioblastoma

    OpenAIRE

    Selch, Michael T.; Tenn, Steve; Agazaryan, Nzhde; Lee, Steve P; Gorgulho, Alessandra; De Salles, Antonio A. F.

    2012-01-01

    Purpose: To retrospectively review the efficacy and safety of image-guided linear accelerator-based radiosurgery for spinal hemangioblastomas. Methods: Between August 2004 and September 2010, nine patients with 20 hemangioblastomas underwent spinal radiosurgery. Five patients had von Hipple–Lindau disease. Four patients had multiple tumors. Ten tumors were located in the thoracic spine, eight in the cervical spine, and two in the lumbar spine. Tumor volume varied from 0.08 to 14.4 cc (median ...

  19. An overview of applications and radiation safety aspects of linear accelerators in Brazilian industry

    International Nuclear Information System (INIS)

    This work presents a brief description of the situation of Brazilian Regulatory Authority about safety control on Industrial Linear Accelerators Installations. It shows the national regulatory infrastructure responsible for radiation safety inspections, the regulation infrastructure, the national inventory of industrial installations, the national system of inspection and enforcement and the national system for qualifying the radiation protection officer. Some results of regulatory safety inspections are also showed in this work. (author)

  20. Complications following linear accelerator based stereotactic radiation for cerebral arteriovenous malformations

    DEFF Research Database (Denmark)

    Skjøth-Rasmussen, Jane; Roed, Henrik; Ohlhues, Lars;

    2010-01-01

    Primarily, gamma knife centers are predominant in publishing results on arteriovenous malformations (AVM) treatments including reports on risk profile. However, many patients are treated using a linear accelerator-most of these at smaller centers. Because this setting is different from a large...... gamma knife center, the risk profile at Linac departments could be different from the reported experience. Prescribed radiation doses are dependent on AVM volume. This study details results from a medium sized Linac department center focusing on risk profiles....

  1. The R&D Works on the High Intensity Proton Linear Accelerator for Nuclear Waste Transmutation

    CERN Document Server

    Ito, N; Ino, H; Kawai, M; Kusano, J; Mizumoto, M; Murata, H; Oguri, H; Okumura, Y; Touchi, Y

    1996-01-01

    The R&D works of the 10MeV/10mA proton linear accelerator have been carried out for last four years. A high brightness hydrogen ion source, an RFQ and an RF power source have been developed and examined to achieve 2MeV proton beam. A DTL hot test model was also fabricated and a high power test has been carried out. The present status of the R&D works are described in this paper.

  2. Craniospinal treatment with IMRT multi-isocentric and image-guided linear accelerator based on Gantry

    International Nuclear Information System (INIS)

    The objective is the realization of craniospinal treatment with a linear accelerator equipped with gantry based on MLC, carbon fiber table and Image Guided capability. The great length of treatment (patient l,80m in height) was a great difficulty for want of full length of the longitudinal movement of the table to adequately cover the PTV, plus free metallic screws fastening the head of the table extender preventing further incidents.

  3. Evaluation of a dispersion medium for the irradiation of blood products in a electron linear accelerator

    International Nuclear Information System (INIS)

    The use of bags of rice as dispersion medium in irradiation of blood products for medical use is less effective than the immersion from the point of view dosimetric water. However, given the wide range of dose values for a valid result and once subjected to quality control procedure, the method provides the necessary work for the irradiation of blood products in a linear electron accelerator. (Author)

  4. Bunch compressor for high-current single bunch electron linear accelerator

    International Nuclear Information System (INIS)

    A bunch compressor with four dipole magnet has been installed and tested on the IRIS-Osaka single bunch electron linear accelerator. The single bunch with a full length of 40 ps is compressed into 12 ps, whereas the bunch length of 16 ps in FWHM is compressed into 9.5 ps. The maximum compression rate is estimated to be about 30% for the single bunch with the charge of 10-40 nC

  5. Study of relativistic magnetron with supply from heavy-current linear induction accelerators

    International Nuclear Information System (INIS)

    The physical processes in the system of the SHF-frequency relativistic generator-power supply characterized by the strong feedback are studied. The computerized model for calculating the output parameters is similar systems represented by the equivalent schemes is developed. The concrete realization of the model is considered by the example of the linear induction accelerator on the magnetic elements, intended for the relativistic magnetron operation, the nonlinear equivalent schemes whereof are determined in accordance with the averaged motion theory

  6. Opportunistic or event-driven maintenance at the Stanford Linear Accelerator Center

    International Nuclear Information System (INIS)

    The Stanford Linear Accelerator Center (SLAC) uses a maintenance management philosophy that is best described as opportunistic or event-driven. Opportunistic maintenance can be defined as a systematic method of collecting, investigating, pre-planning, and publishing a set of proposed maintenance tasks and acting on them when there is an unscheduled failure or repair ''opportunity''. Opportunistic maintenance can be thought of as a modification of the run-to-fail maintenance management philosophy. This maintenance plan was adopted and developed to improve the overall availability of SLAC's linear accelerator, beam delivery systems, and associated controls, power systems, and utilities. In the late 1980's, as the technical complexity of the accelerator facility increased, variations on a conventional maintenance plan were used with mixed results. These variations typically included some type of regular periodic interruption to operations. The periodic shutdowns and unscheduled failures were additive and resulted in unsatisfactory availability. Maintenance issues are evaluated in a daily meeting that includes the accelerator managers, maintenance supervisors and managers, safety office personnel, program managers, and accelerator operators. Lists of pending maintenance tasks are made available to the general SLAC population by a World Wide Web site on a local internet. A conventional information system which pre-dates the WWW site is still being used to provide paper copies to groups that are not yet integrated into the WWW system. The local internet provides real time maintenance information, allowing people throughout the facility to track progress on tasks with essentially real-time status updates. With the introduction of opportunistic maintenance, the accelerator's availability has been measurably better. This paper will discuss processes, rolls and responsibilities of key maintenance groups, and management tools developed to support opportunistic maintenance

  7. Orbit correction of the electron beam using the linear accelerator model at SACLA

    International Nuclear Information System (INIS)

    In the X-ray free-electron laser facility SACLA, 24 hours continuous operation for the user experiments has been started from March 2012. To achieve stable XFEL operation, the stability of the electron beam orbit is one of important issues. We have introduced two orbit feedback systems. One is installed at the entrance of the undulator-beamline to maintain the beam orbit through the undulator beamline, which contributes to the laser axis stability. The other is a global orbit correction system over the whole linear accelerator to mainly keep the projected beam emittance, which contributes to the laser intensity stability. Since the previous accelerator model using linear transfer matrices does not reproduce observed beam orbit responses in SACLA, response functions for each steering magnet had been measured and used for the orbit correction. Recently we found that the disagreement of the previous model is due to the quadrupole components existing in the accelerator structures. In this report, we present the results of the beam orbit correction using the modified accelerator model including the quadrupole components. (author)

  8. Study of dose distribution for stereotactic irradiation. Evolution of using gamma unit and linear accelerator

    International Nuclear Information System (INIS)

    Currently used stereotactic irradiation techniques that employ high-energy photon beams are based either on a gamma unit that uses stationary 201-cobalt beams or on isocentric linear accelerators. The techniques that rely on linear accelerators are divided into multiple non-coplanar converging arcs, precessional convergent irradiation, and others. These techniques have respective physical characteristics, for example, the precision of dose convergence and isodose distributions. We discuss the physical characteristics of the gamma unit, multiple non-coplanar converging arcs, and precessional convergent irradiation. In terms of the precision of dose convergence, the best was the gamma unit, followed by precessional convergent irradiation, with multiple non-coplanar converging arcs third. The precision of dose convergence deteriorated with diminishing field size in all techniques, and the precision of dose convergence was improved using a circular field with supplementary collimator among the techniques using linear accelerators. In addition, stereotactic irradiation techniques should be examined for disease treatment and running cost, because the techniques that have the greatest precision in dose convergence are incompatible with all-purpose usage. (author)

  9. Control of Switching Characteristics of Silicon-based Semiconductor Diode Using High Energy Linear Accelerator

    Directory of Open Access Journals (Sweden)

    N. Harihara Krishnan

    2013-05-01

    Full Text Available This paper reports control of switching characteristics of silicon-based semiconductor diode using electron beam produced using linear accelerator. Conventionally, p-n junction chips of diode are exposed to gamma rays from a radioactive source or electron beam from a microtron, depending upon the required level of correction. High energy linear accelerators featuring simultaneous exposure of multiple chips are recent advancements in radiation technology. The paper presents the results of the radiation process using a 10 MeV linear accelerator as applied in industrial manufacturing of a high voltage diode (2600 V. The achieved values of reverse recovery time were found to be within the design limits. The suitability of the new process was verified by constructing the trade-off curve between the switching and conduction parameters of the diode for the complete range using large number of experimental samples. The paper summarizes the advantages of the new process over the conventional methods specifically with reference to industrial requirements. The developed process has been successfully implemented in semiconductor manufacturing.

  10. Medical linear accelerator mounted mini-beam collimator: design, fabrication and dosimetric characterization

    International Nuclear Information System (INIS)

    The goal of this work was to design, build and experimentally characterize a linear accelerator mounted mini-beam collimator for use at a nominal 6 MV beam energy. Monte Carlo simulation was used in the design and dosimetric characterization of a compact mini-beam collimator assembly mounted to a medical linear accelerator. After fabrication, experimental mini-beam dose profiles and central axis relative output were measured and the results used to validate the simulation data. The simulation data was then used to establish traceability back to an established dosimetric code of practice. The Monte Carlo simulation work revealed that changes in collimator blade width have a greater influence on the valley-to-peak dose ratio than do changes in blade height. There was good agreement between the modeled and measured profile data, with the exception of small differences on either side of the central peak dose. These differences were found to be systematic across all depths and result from limitations associated with the collimator fabrication. Experimental mini-beam relative output and simulation data agreed to better than  ±2.0%, which is well within the level of uncertainty required for dosimetric traceability of non-standard field geometries. A mini-beam collimator has now been designed, built and experimentally characterized for use with a commercial linear accelerator operated at a nominal 6 MV beam energy. (paper)

  11. Analytical researches on the accelerating structures, wakefields, and beam dynamics for future linear colliders

    International Nuclear Information System (INIS)

    The research works presented in this memoir are oriented not only to the R and D programs towards future linear colliders, but also to the pedagogic purposes. The first part of this memoir (from Chapter 2 to Chapter 9) establishes an analytical framework of the disk-loaded slow wave accelerating structures with can be served as the advanced courses for the students who have got some basic trainings in the linear accelerator theories. The analytical formulae derived in this part describe clearly the properties of the disk-loaded accelerating structures, such as group velocity, shunt impedance, coupling coefficients κ and β, loss factors, and wake fields. The second part (from Chapter 11 to Chapter 13) gives the beam dynamics simulations and the final proposal of an S-Band Superconducting Linear Collider (SSLC) which is aimed to avoid the dark current problem in TESLA project. This memoir has not included all the works conducted since April 1992, such as beam dynamics simulations for CLIC Test Facility (CFT-2) and the design of High Charge Structures (HCS) (11π/12 mode) for CFT-2, in order to make this memoir more harmonious, coherent and continuous. (author)

  12. Vibration isolation measures due to the high sensitive linear accelerator at the Paul Scherrer Institute

    Directory of Open Access Journals (Sweden)

    Trombik Peter

    2015-01-01

    Full Text Available The new 735m long linear accelerator “SwissFEL” at the Paul Scherrer Institute (PSI in Würenlingen is extremely sensitive against vibrations coming from surrounding equipment (pumps, ventilators, transformers, etc.. The manufacturer’s vibration limit for this linear accelerator is 0.1μm displacement amplitude. Therefore, all vibration sources must strictly be isolated to the highest-possible degree from the rest of the structure. This paper discusses the vibration situation in general for this unique construction (ground vibrations, vibration propagations / structural amplifications, vibration limits, etc. and as a case study the isolation of a pump located in the building. Steel springs were used and it was achieved to reduce the vibration transmitted to the floor by more than 99%, to a level where the coherent component of the motion recorded on the floor next to the linear accelerator is non-measurable / below the ground motions. The measurements were found to be in good accordance with the FEM model used.

  13. Perception of tilt (somatogravic illusion) in response to sustained linear acceleration during space flight

    Science.gov (United States)

    Clement, G.; Moore, S. T.; Raphan, T.; Cohen, B.

    2001-01-01

    During the 1998 Neurolab mission (STS-90), four astronauts were exposed to interaural and head vertical (dorsoventral) linear accelerations of 0.5 g and 1 g during constant velocity rotation on a centrifuge, both on Earth and during orbital space flight. Subjects were oriented either left-ear-out or right-ear-out (Gy centrifugation), or lay supine along the centrifuge arm with their head off-axis (Gz centrifugation). Pre-flight centrifugation, producing linear accelerations of 0.5 g and 1 g along the Gy (interaural) axis, induced illusions of roll-tilt of 20 degrees and 34 degrees for gravito-inertial acceleration (GIA) vector tilts of 27 degrees and 45 degrees , respectively. Pre-flight 0.5 g and 1 g Gz (head dorsoventral) centrifugation generated perceptions of backward pitch of 5 degrees and 15 degrees , respectively. In the absence of gravity during space flight, the same centrifugation generated a GIA that was equivalent to the centripetal acceleration and aligned with the Gy or Gz axes. Perception of tilt was underestimated relative to this new GIA orientation during early in-flight Gy centrifugation, but was close to the GIA after 16 days in orbit, when subjects reported that they felt as if they were 'lying on side'. During the course of the mission, inflight roll-tilt perception during Gy centrifugation increased from 45 degrees to 83 degrees at 1 g and from 42 degrees to 48 degrees at 0.5 g. Subjects felt 'upside-down' during in-flight Gz centrifugation from the first in-flight test session, which reflected the new GIA orientation along the head dorsoventral axis. The different levels of in-flight tilt perception during 0.5 g and 1 g Gy centrifugation suggests that other non-vestibular inputs, including an internal estimate of the body vertical and somatic sensation, were utilized in generating tilt perception. Interpretation of data by a weighted sum of body vertical and somatic vectors, with an estimate of the GIA from the otoliths, suggests that

  14. Non-linear stochastic optimal control of acceleration parametrically excited systems

    Science.gov (United States)

    Wang, Yong; Jin, Xiaoling; Huang, Zhilong

    2016-02-01

    Acceleration parametrical excitations have not been taken into account due to the lack of physical significance in macroscopic structures. The explosive development of microtechnology and nanotechnology, however, motivates the investigation of the acceleration parametrically excited systems. The adsorption and desorption effects dramatically change the mass of nano-sized structures, which significantly reduces the precision of nanoscale sensors or can be reasonably utilised to detect molecular mass. This manuscript proposes a non-linear stochastic optimal control strategy for stochastic systems with acceleration parametric excitation based on stochastic averaging of energy envelope and stochastic dynamic programming principle. System acceleration is approximately expressed as a function of system displacement in a short time range under the conditions of light damping and weak excitations, and the acceleration parametrically excited system is shown to be equivalent to a constructed system with an additional displacement parametric excitation term. Then, the controlled system is converted into a partially averaged Itô equation with respect to the total system energy through stochastic averaging of energy envelope, and the optimal control strategy for the averaged system is derived from solving the associated dynamic programming equation. Numerical results for a controlled Duffing oscillator indicate the efficacy of the proposed control strategy.

  15. The linear accelerator and pulse compressor of the SNQ-project

    International Nuclear Information System (INIS)

    The Spallation Neutron Source is one of Germany's most important scientific projects proposed at present. Its main purpose is to provide short neutron bursts of high intensity which are produced by a pulsed proton beam hitting a target. The proton beam itself will also be used directly for a series of very important experiments in nuclear physics. The performance requested from the proton accelerator part of the project with respect to average intensity and pulse rate limits the choice of all technical solutions to a combination of a high duty Linac and an additional pulse compressing synchrotron ring. The concept of the accelerator part of the SNQ-project, in particular the Linac, will be described. The Linac may be subdivided into three sections, namely the Injector with two RFQ-structures and a beam merging by funneling, the Alvarez-Accelerator and the High Energy Linear Accelerator with its single cell structure. For the ring shaped pulse compressor two technical solutions are being investigated. One is a isochronous storage ring and the other is a FFAG-synchrotron, which can also accelerate at a fast rate. (orig.)

  16. Effect of diaphragms on electron beam stability in a linear induction accelerator

    International Nuclear Information System (INIS)

    In diaphragms used for protection of accelerating tube of a linear induction accelerator from electron impinge, the electron beam being translated as to the axis induces currents, partially compensating the effect of the induced charges. Therefore, one can expect that when selecting certain geometry of the diaphraqms the limitations for the accelerator parameters will be considerably reduced. The sequence of diaphragms however is the beam energy degrader, the interaction with it being able to cause the instability of the beam high-frequency oscillations. In the present work the effect of the beam electromagnetic field screening by means of the sequence of diaphragms on the stability of the beam transverse motion has been studied. It is shown, that the rise of transverse oscillations amplitude can be reduced at the expense of the increase of the channel radius and focusing field intensity, as well as the decrease of screening factor, which can be achieved by the increase of the structure period. It is also shown, that arrangement of the accelerator sections, when voltage, created by all inductors of sections, is applied to one accelerating gap, is more preferable

  17. Accelerated solution of non-linear flow problems using Chebyshev iteration polynomial based RK recursions

    Energy Technology Data Exchange (ETDEWEB)

    Lorber, A.A.; Carey, G.F.; Bova, S.W.; Harle, C.H. [Univ. of Texas, Austin, TX (United States)

    1996-12-31

    The connection between the solution of linear systems of equations by iterative methods and explicit time stepping techniques is used to accelerate to steady state the solution of ODE systems arising from discretized PDEs which may involve either physical or artificial transient terms. Specifically, a class of Runge-Kutta (RK) time integration schemes with extended stability domains has been used to develop recursion formulas which lead to accelerated iterative performance. The coefficients for the RK schemes are chosen based on the theory of Chebyshev iteration polynomials in conjunction with a local linear stability analysis. We refer to these schemes as Chebyshev Parameterized Runge Kutta (CPRK) methods. CPRK methods of one to four stages are derived as functions of the parameters which describe an ellipse {Epsilon} which the stability domain of the methods is known to contain. Of particular interest are two-stage, first-order CPRK and four-stage, first-order methods. It is found that the former method can be identified with any two-stage RK method through the correct choice of parameters. The latter method is found to have a wide range of stability domains, with a maximum extension of 32 along the real axis. Recursion performance results are presented below for a model linear convection-diffusion problem as well as non-linear fluid flow problems discretized by both finite-difference and finite-element methods.

  18. Effects of Frequency and Motion Paradigm on Perception of Tilt and Translation During Periodic Linear Acceleration

    Science.gov (United States)

    Beaton, K. H.; Holly, J. E.; Clement, G. R.; Wood, Scott J.

    2009-01-01

    Previous studies have demonstrated an effect of frequency on the gain of tilt and translation perception. Results from different motion paradigms are often combined to extend the stimulus frequency range. For example, Off-Vertical Axis Rotation (OVAR) and Variable Radius Centrifugation (VRC) are useful to test low frequencies of linear acceleration at amplitudes that would require impractical sled lengths. The purpose of this study was to compare roll-tilt and lateral translation motion perception in 12 healthy subjects across four paradigms: OVAR, VRC, sled translation and rotation about an earth-horizontal axis. Subjects were oscillated in darkness at six frequencies from 0.01875 to 0.6 Hz (peak acceleration equivalent to 10 deg, less for sled motion below 0.15 Hz). Subjects verbally described the amplitude of perceived tilt and translation, and used a joystick to indicate the direction of motion. Consistent with previous reports, tilt perception gain decreased as a function of stimulus frequency in the motion paradigms without concordant canal tilt cues (OVAR, VRC and Sled). Translation perception gain was negligible at low stimulus frequencies and increased at higher frequencies. There were no significant differences between the phase of tilt and translation, nor did the phase significantly vary across stimulus frequency. There were differences in perception gain across the different paradigms. Paradigms that included actual tilt stimuli had the larger tilt gains, and paradigms that included actual translation stimuli had larger translation gains. In addition, the frequency at which there was a crossover of tilt and translation gains appeared to vary across motion paradigm between 0.15 and 0.3 Hz. Since the linear acceleration in the head lateral plane was equivalent across paradigms, differences in gain may be attributable to the presence of linear accelerations in orthogonal directions and/or cognitive aspects based on the expected motion paths.

  19. Commissioning and early experience with a new-generation low-energy linear accelerator with advanced delivery and imaging functionalities

    Directory of Open Access Journals (Sweden)

    Fogliata Antonella

    2011-09-01

    Full Text Available Abstract Background A new-generation low-energy linear accelerator (UNIQUE was introduced in the clinical arena during 2009 by Varian Medical Systems. The world's first UNIQUE was installed at Oncology Institute of Southern Switzerland and put into clinical operation in June 2010. The aim of the present contribution was to report experience about its commissioning and first year results from clinical operation. Methods Commissioning data, beam characteristics and the modeling into the treatment planning system were summarized. Imaging system of UNIQUE included a 2D-2D matching capability and tests were performed to identify system repositioning capability. Finally, since the system is capable of delivering volumetric modulated arc therapy with RapidArc, a summary of the tests performed for such modality to assess its performance in preclinical settings and during clinical usage was included. Results Isocenter virtual diameter was measured as less than 0.2 mm. Observed accuracy of isocenter determination and repositioning for 2D-2D matching procedures in image guidance was Conclusions The results of the commissioning tests and of the first period of clinical operation, resulted meeting specifications and having good margins respect to tolerances. UNIQUE was put into operation for all delivery techniques; in particular, as shown by the pre-treatment quality assurance results, it enabled accurate and safe delivery of RapidArc plans.

  20. Beam dynamics in a linear accelerator for generations of short electron beams and femtosecond hard X-ray pulses

    International Nuclear Information System (INIS)

    We investigate a linear accelerator system capable of generating short electron beams and femtosecond hard X-ray pulses. We show a detailed for a two-stage bunch compressor to generate the short electron beams in the linear accelerator. The bunch compressor system consists of two chicanes with a short system length that can compress an electron bunch of 0.6 nC and beam energy of 162 MeV, from 3 to 0.5 ps rms. One important design issue in the bunch compressor is to make as small growths of the emittance and energy spread as possible. The normalized horizontal emittance of 3 mm mrad is increased by approximately 10% due to coherent synchrotron radiation in the designed bunch compressor. Lattice distortions due to machine errors associate with quadrupole magnets, bending magnets and beam position monitors in the linear accelerator were investigated. It is shown that the lattice distortions due to the machine errors can be easily compensated by performing both orbit correction and dispersion correction in the linear accelerator. We have performed tolerance studies due to the various jitter sources in the linear accelerator to examine their sensitivities on the beam quality. From these results, it is shown that the linear accelerator system provides sufficient tolerances to maintain stable electron beams. We also investigated the generation of femtosecond hard X-ray pulses that may be provided by the interactions at 90deg of the short electron beams in the linear accelerator with a laser system. It is shown that 3.4x106 photons within 10% bandwidth at 0.04 A wavelength in about 350 fs rms pulse may be provided using the linear accelerator system. We presented studies on beam dynamics in the linear accelerator system that may provide the short beams and intense X-ray pulses. (author)

  1. Introduction of design and construction electron linear accelerator project in Institute for Research in Fundamental Sciences(IPM

    Directory of Open Access Journals (Sweden)

    M Lamehi Rashti

    2015-09-01

    Full Text Available One of the most commonly used types of accelerators is linear electron accelerator. There is a project is in progress in Institute for research in fundamental sciences (IPM aiming to design and build such an accelerator. It is defined in such a way that all parts to be built in Iran as possibly as it can. In this paper, after a brief explanation of the components of an electron linear accelerator; including the electron gun, accelerating tube, RF power supply, vacuum system, waveguide for transmitting RF power to accelerating tube, and cooling system; specification of each of these components are presented. The maximum beam energy of 15 MeV and RF pulse power of 2.5 MW with a traveling wave structure at a frequency of 2998 MHz which is acted in π /2 mode are the most important features of this accelerator

  2. Evolution of the Argonne Tandem Linear Accelerator System (ATLAS) control system

    International Nuclear Information System (INIS)

    Given that the Argonne Tandem Linear Accelerator System (ATLAS) recently celebrated its 25. anniversary, this paper will explore the past, present, and future of the ATLAS Control System, and how it has evolved along with the accelerator and control system technology. ATLAS as we know it today, originated with a Tandem Van de Graff in the sixties. With the addition of the Booster section in the late seventies, came the first computerized control. ATLAS itself was placed into service on June 25, 1985, and was the world's first superconducting linear accelerator for ions. Since its dedication as a National User Facility, more than a thousand experiments by more than 2,000 users worldwide, have taken advantage of the unique capabilities it provides. Today, ATLAS continues to be a user facility for physicists who study the particles that form the heart of atoms. Its most recent addition, CARIBU (Californium Rare Isotope Breeder Upgrade), creates special beams that feed into ATLAS. ATLAS is similar to a living organism, changing and responding to new technological challenges and research needs. As it continues to evolve, so does the control system: from the original days using a DEC PDP-11/34 computer and two CAMAC crates, to a DEC Alpha computer running Vsystem software and more than twenty CAMAC crates, to distributed computers and VME systems. Future upgrades are also in the planning stages that will continue to evolve the control system. (authors)

  3. The generation and acceleration of low emittance flat beams for future linear colliders

    International Nuclear Information System (INIS)

    Many future linear collider designs call for electron and positron beams with normalized rms horizontal and vertical emittances of γεx = 3x10-6 m-rad and γεy = 3x10-8 m-rad; these are a factor of 10 to 100 below those observed in the Stanford Linear Collider. In this dissertation, we examine the feasibility of achieving beams with these very small vertical emittances. We examine the limitations encountered during both the generation and the subsequent acceleration of such low emittance beams. We consider collective limitations, such as wakefields, space charge effects, scattering processes, and ion trapping; and also how intensity limitations, such as anomalous dispersion, betatron coupling, and pulse-to-pulse beam jitter. In general, the minimum emittance in both the generation and the acceleration stages is limited by the transverse misalignments of the accelerator components. We describe a few techniques of correcting the effect of these errors, thereby easing the alignment tolerances by over an order of magnitude. Finally, we also calculate ''fundamental'' limitations on the minimum vertical emittance; these do not constrain the current designs but may prove important in the future

  4. The International Linear Collider Technical Design Report - Volume 3.II: Accelerator Baseline Design

    CERN Document Server

    Adolphsen, Chris; Barish, Barry; Buesser, Karsten; Burrows, Philip; Carwardine, John; Clark, Jeffrey; Durand, Helene Mainaud; Dugan, Gerry; Elsen, Eckhard; Enomoto, Atsushi; Foster, Brian; Fukuda, Shigeki; Gai, Wei; Gastal, Martin; Geng, Rongli; Ginsburg, Camille; Guiducci, Susanna; Harrison, Mike; Hayano, Hitoshi; Kershaw, Keith; Kubo, Kiyoshi; Kuchler, Victor; List, Benno; Liu, Wanming; Michizono, Shinichiro; Nantista, Christopher; Osborne, John; Palmer, Mark; Paterson, James McEwan; Peterson, Thomas; Phinney, Nan; Pierini, Paolo; Ross, Marc; Rubin, David; Seryi, Andrei; Sheppard, John; Solyak, Nikolay; Stapnes, Steinar; Tauchi, Toshiaki; Toge, Nobu; Walker, Nicholas; Yamamoto, Akira; Yokoya, Kaoru

    2013-01-01

    The International Linear Collider Technical Design Report (TDR) describes in four volumes the physics case and the design of a 500 GeV centre-of-mass energy linear electron-positron collider based on superconducting radio-frequency technology using Niobium cavities as the accelerating structures. The accelerator can be extended to 1 TeV and also run as a Higgs factory at around 250 GeV and on the Z0 pole. A comprehensive value estimate of the accelerator is give, together with associated uncertainties. It is shown that no significant technical issues remain to be solved. Once a site is selected and the necessary site-dependent engineering is carried out, construction can begin immediately. The TDR also gives baseline documentation for two high-performance detectors that can share the ILC luminosity by being moved into and out of the beam line in a "push-pull" configuration. These detectors, ILD and SiD, are described in detail. They form the basis for a world-class experimental programme that promises to incr...

  5. The generation and acceleration of low emittance flat beams for future linear colliders

    Energy Technology Data Exchange (ETDEWEB)

    Raubenheimer, T.O.

    1991-11-01

    Many future linear collider designs call for electron and positron beams with normalized rms horizontal and vertical emittances of {gamma}{epsilon}{sub x} = 3{times}10{sup {minus}6} m-rad and {gamma}{epsilon}{sub y} = 3{times}10{sup {minus}8} m-rad; these are a factor of 10 to 100 below those observed in the Stanford Linear Collider. In this dissertation, we examine the feasibility of achieving beams with these very small vertical emittances. We examine the limitations encountered during both the generation and the subsequent acceleration of such low emittance beams. We consider collective limitations, such as wakefields, space charge effects, scattering processes, and ion trapping; and also how intensity limitations, such as anomalous dispersion, betatron coupling, and pulse-to-pulse beam jitter. In general, the minimum emittance in both the generation and the acceleration stages is limited by the transverse misalignments of the accelerator components. We describe a few techniques of correcting the effect of these errors, thereby easing the alignment tolerances by over an order of magnitude. Finally, we also calculate fundamental'' limitations on the minimum vertical emittance; these do not constrain the current designs but may prove important in the future.

  6. AMS of heavy elements with an ECR ion source and the ATLAS linear accelerator

    CERN Document Server

    Paul, M; Ahmad, I; Borasi, F; Caggiano, J; Davids, C N; Greene, J P; Harss, B; Heinz, A; Henderson, D J; Henning, W F; Jiang, C L; Pardo, R C; Rehm, K E; Rejoub, R; Seweryniak, D; Sonzogni, A; Uusitalo, J; Vondrasek, R C

    2000-01-01

    Detection of heavy elements by accelerator mass spectrometry with the electron cyclotron resonance ion source, Argonne linear accelerator and fragment mass analyzer (ECRIS-ATLAS-FMA) system has been developed. The use of the ECR-ATLAS system for AMS of heavy elements has two interesting features: (i) the efficient production of high-charge state ions in the ECR source ensures the elimination of molecular ions at the source stage, a highly attractive feature for any mass-spectrometric use not exploited so far; (ii) the linear acceleration based on velocity matching and the beam transport system act as a powerful mass filter for background suppression. We have shown that our system reaches an abundance sensitivity of 1x10 sup - sup 1 sup 4 for Pb isotopes. The sup 2 sup 3 sup 6 U detection sensitivity is sup 2 sup 3 sup 6 U/U > or approx. 1x10 sup - sup 1 sup 2 , limited mainly by the ion source output.

  7. Verification of volumetric-modulated arc therapy plan by long-file analysis of linear accelerator

    International Nuclear Information System (INIS)

    Objective: To verify the dose delivery accuracy of volumetric-modulated arc therapy plan by log-file analysis of linear accelerator that can be created when a dynamic delivery occurs. Methods: Accelerator log file in binary format recorded the accelerator execution plan for each control point corresponding to the gantry angle, multi-leaf collimator leave position, cumulative machine monitor units (MU). These information were read from the accelerator log file with Matlab7.1, then the original control points in the plan file replaced the corresponding information for the log,which generated a new plan. New plan was exported into the planning system to recalculate the dose. The volume dose histogram (DVH) and dose distribution was contrasted to determine the accuracy of the accelerator plan of implementation between two plans. Results: Compared with the original plan, gantry angle difference over ± 1° accounted for about 35% of the entire arc of control points in 4 of 12 arcs and the percentage of the leave error of ±0.5 mm was about 95%. MU error of a single control point was larger, but the cumulative MU for each are was small which was located between-0.09% to 0.11% in the selected 12 arcs. Between the targets, the maximum dose,minimum dose, the mean dose differences were from -0.07% to 0.42%, -0.38% to 0.40%, 0.03% to 0.08%, respectively. The maximum dose and mean dose differences of organs at risks were located from -1.16% to 2.51%, -1.21% to 3.12%, respectively. Conclusions: Accelerator log-file analysis to verify the VMAT plan nan be supplied to the experimental method supplement. (authors)

  8. SU-E-T-543: Measurement of Neutron Activation From Different High Energy Varian Linear Accelerators

    International Nuclear Information System (INIS)

    Purpose: Linear accelerators producing photons above 10 MeV may induce photonuclear reactions in high Z components of the accelerator. These liberated neutrons can then activate the structural components of the accelerator and other materials in the beam path through neutron capture reactions. The induced activity within the accelerator may contribute to additional dose to both patients and personnel. This project seeks to determine the total activity and activity per activated isotope following irradiation in different Varian accelerators at energies above 10 MeV. Methods: A Varian 21IX accelerator was used to irradiate a 30 cm × 30 cm × 20 cm solid water phantom with 15 MV x-rays. The phantom was placed at an SSD of 100 cm and at the center of a 20 cm × 20 cm field. Activation induced gamma spectra were acquired over a 5 minute interval after 1 and 15 minutes from completion of the irradiation. All measurements were made using a CANBERRA Falcon 5000 Portable HPGe detector. The majority of measurements were made in scattering geometry with the detector situated at 90° to the incident beam, 30 cm from the side of the phantom and approximately 10 cm from the top. A 5 minute background count was acquired and automatically subtracted from all subsequent measurements. Photon spectra were acquired for both open and MLC fields. Results: Based on spectral signatures, nuclides have been identified and their activities calculated for both open and MLC fields. Preliminary analyses suggest that activities from the activation products in the microcurie range. Conclusion: Activation isotopes have been identified and their relative activities determined. These activities are only gross estimates since efficiencies have not been determined for this source-detector geometry. Current efforts are focused on accurate determination of detector efficiencies using Monte Carlo calculations

  9. GPU Linear Algebra Libraries and GPGPU Programming for Accelerating MOPAC Semiempirical Quantum Chemistry Calculations.

    Science.gov (United States)

    Maia, Julio Daniel Carvalho; Urquiza Carvalho, Gabriel Aires; Mangueira, Carlos Peixoto; Santana, Sidney Ramos; Cabral, Lucidio Anjos Formiga; Rocha, Gerd B

    2012-09-11

    In this study, we present some modifications in the semiempirical quantum chemistry MOPAC2009 code that accelerate single-point energy calculations (1SCF) of medium-size (up to 2500 atoms) molecular systems using GPU coprocessors and multithreaded shared-memory CPUs. Our modifications consisted of using a combination of highly optimized linear algebra libraries for both CPU (LAPACK and BLAS from Intel MKL) and GPU (MAGMA and CUBLAS) to hasten time-consuming parts of MOPAC such as the pseudodiagonalization, full diagonalization, and density matrix assembling. We have shown that it is possible to obtain large speedups just by using CPU serial linear algebra libraries in the MOPAC code. As a special case, we show a speedup of up to 14 times for a methanol simulation box containing 2400 atoms and 4800 basis functions, with even greater gains in performance when using multithreaded CPUs (2.1 times in relation to the single-threaded CPU code using linear algebra libraries) and GPUs (3.8 times). This degree of acceleration opens new perspectives for modeling larger structures which appear in inorganic chemistry (such as zeolites and MOFs), biochemistry (such as polysaccharides, small proteins, and DNA fragments), and materials science (such as nanotubes and fullerenes). In addition, we believe that this parallel (GPU-GPU) MOPAC code will make it feasible to use semiempirical methods in lengthy molecular simulations using both hybrid QM/MM and QM/QM potentials. PMID:26605718

  10. A history of thyratron lifetimes at the Stanford Linear Accelerator Center

    Energy Technology Data Exchange (ETDEWEB)

    Ficklin, D.B. Jr.

    1994-12-01

    The Stanford Linear Accelerator Center (SLAC) has been in almost continuous operation since the middle 1960s, providing a remarkable opportunity to amass thyratron data. This paper reviews the history of this thyratron usage, focusing primarily on data collected during the last ten years of accelerator operation. There have been two distinct operating conditions during the history of operation at SLAC. Prior to 1985, the fundamental thyratron operating points were 46 kV anode voltage (Epy), 4.2 kA peak current, 3.8 {mu}s equivalent square pulse (esp), with a maximum repetition rate of 360 pulses per second (pps). The accelerator was upgraded during 1985, and the thyratron operating points are now 46 kV Epy, 6.3 kA, 5.4 {mu}s esp, with a maximum repetition rate of 120 pps. The SLAC high-energy physics research program requires that each of the available modulator klystron units provide a stable microwave energy source. Within these constraints, this paper explores historical thyratron lifetimes at SLAC, reviewing the available data to determine how long these thyratrons can be expected to operate before failure currently or recently used in the 243 accelerator modulators.

  11. A history of thyratron lifetimes at the Stanford Linear Accelerator Center

    International Nuclear Information System (INIS)

    The Stanford Linear Accelerator Center (SLAC) has been in almost continuous operation since the middle 1960s, providing a remarkable opportunity to amass thyratron data. This paper reviews the history of this thyratron usage, focusing primarily on data collected during the last ten years of accelerator operation. There have been two distinct operating conditions during the history of operation at SLAC. Prior to 1985, the fundamental thyratron operating points were 46 kV anode voltage (Epy), 4.2 kA peak current, 3.8 μs equivalent square pulse (esp), with a maximum repetition rate of 360 pulses per second (pps). The accelerator was upgraded during 1985, and the thyratron operating points are now 46 kV Epy, 6.3 kA, 5.4 μs esp, with a maximum repetition rate of 120 pps. The SLAC high-energy physics research program requires that each of the available modulator klystron units provide a stable microwave energy source. Within these constraints, this paper explores historical thyratron lifetimes at SLAC, reviewing the available data to determine how long these thyratrons can be expected to operate before failure currently or recently used in the 243 accelerator modulators

  12. SEE induced in SRAM operating in a superconducting electron linear accelerator environment

    Science.gov (United States)

    Makowski, D.; Mukherjee, Bhaskar; Grecki, M.; Simrock, Stefan

    2005-02-01

    Strong fields of bremsstrahlung photons and photoneutrons are produced during the operation of high-energy electron linacs. Therefore, a mixed gamma and neutron radiation field dominates the accelerators environment. The gamma radiation induced Total Ionizing Dose (TID) effect manifests the long-term deterioration of the electronic devices operating in accelerator environment. On the other hand, the neutron radiation is responsible for Single Event Effects (SEE) and may cause a temporal loss of functionality of electronic systems. This phenomenon is known as Single Event Upset (SEU). The neutron dose (KERMA) was used to scale the neutron induced SEU in the SRAM chips. Hence, in order to estimate the neutron KERMA conversion factor for Silicon (Si), dedicated calibration experiments using an Americium-Beryllium (241Am/Be) neutron standard source was carried out. Single Event Upset (SEU) influences the short-term operation of SRAM compared to the gamma induced TID effect. We are at present investigating the feasibility of an SRAM based real-time beam-loss monitor for high-energy accelerators utilizing the SEU caused by fast neutrons. This paper highlights the effects of gamma and neutron radiations on Static Random Access Memory (SRAM), placed at selected locations near the Superconducting Linear Accelerator driving the Vacuum UV Free Electron Laser (VUVFEL) of DESY.

  13. Suppressing beam-centroid motion in a long-pulse linear induction accelerator

    Science.gov (United States)

    Ekdahl, Carl; Abeyta, E. O.; Archuleta, R.; Bender, H.; Broste, W.; Carlson, C.; Cook, G.; Frayer, D.; Harrison, J.; Hughes, T.; Johnson, J.; Jacquez, E.; McCuistian, B. Trent; Montoya, N.; Nath, S.; Nielsen, K.; Rose, C.; Schulze, M.; Smith, H. V.; Thoma, C.; Tom, C. Y.

    2011-12-01

    The second axis of the dual-axis radiography of hydrodynamic testing (DARHT) facility produces up to four radiographs within an interval of 1.6μs. It does this by slicing four micropulses out of a 2-μs long electron beam pulse and focusing them onto a bremsstrahlung converter target. The 1.8-kA beam pulse is created by a dispenser cathode diode and accelerated to more than 16 MeV by the unique DARHT Axis-II linear induction accelerator (LIA). Beam motion in the accelerator would be a problem for multipulse flash radiography. High-frequency motion, such as from beam-breakup (BBU) instability, would blur the individual spots. Low-frequency motion, such as produced by pulsed-power variation, would produce spot-to-spot differences. In this article, we describe these sources of beam motion, and the measures we have taken to minimize it. Using the methods discussed, we have reduced beam motion at the accelerator exit to less than 2% of the beam envelope radius for the high-frequency BBU, and less than 1/3 of the envelope radius for the low-frequency sweep.

  14. A study of an electron gun controlled with a meshless grid for a linear accelerator

    International Nuclear Information System (INIS)

    An electron gun for a linear accelerator with a control grid of meshless electrode (meshless grid) is expected to overcome some disadvantages of beam quality using an ordinary mesh grid. A gun of this type was designed and its characteristics were numerically analyzed. The simulation program code Egn2 with a boundary setting routine POLYGON was used. The result indicated that the grid can control the beam launched from the cathode to the anode electrode. It also indicated the Ip-Vp and Ip-Vp characteristics which are different from an ordinary triode gun with a mesh-grid. The mutual conductance gm of 0.4[mS], the maximum average current of 1.6[A] and cut-off voltage -200[V] were obtained under a condition of 200[kV] acceleration voltage. (author)

  15. Evaluation of the alignment for long linear accelerators using a level

    International Nuclear Information System (INIS)

    We have studied to adopt a level, which is a gravity referenced precise inclinometer, for evaluating alignment of large linear accelerators, which is several hundred meters or larger. It has advantages for evaluating large objects because it is hardly affected by shape references, which becomes difficult to be defined enough accurate as the objects becomes large. We had already evaluated the vertical aligning straightness of the reference plates for the 70-m-long part of the KEK injector linear accelerator (KEK linac) with the standard deviations of less than 49 μm by using a level on a straight bar. The results are fairly reliable having good agreement within sub-mm range with those by the other methods; however, the evaluation distances were limited by obstacles which block the measurement path. Here, we devised new method which adopts two offset bars for avoiding the obstacles. Their one ends are placed on the measurement points with their axis directed perpendicular to the measurement path. One can avoid the obstacles by measuring the slope angles between the far ends of each offset bars instead of measuring directly those between the measurement points. Error arises from the offset bars can be eliminated by reversal measurement, which considers slope angles of the offset bars. As a result, straightness for the 206-m-long part of the linac, which corresponds to the three successive accelerator sectors of the linac, could be evaluated with our new method. The reproducibility expressed by the standard deviation of the slope angles for the arbitrarily sampled measurement point was 15 μrad, which is comparable with the average of our former measurements of 10 μrad. Moreover, the result agrees with those by the alignment telescope and our laser-based alignment system partially within sub-mm range. They indicate that our new method can be applicable for evaluating alignment of large accelerators in spite of its complexity caused by the offset bars. (author)

  16. Visual Outcome in Meningiomas Around Anterior Visual Pathways Treated With Linear Accelerator Fractionated Stereotactic Radiotherapy

    International Nuclear Information System (INIS)

    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.

  17. 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.

  18. Laboratory Measurements of Linear Electron Acceleration by Inertial Alfvén Waves

    Science.gov (United States)

    Schroeder, J. W. R.

    2015-11-01

    Alfvén waves occur in conjunction with a significant fraction of auroral electron acceleration. Inertial mode Alfvén waves (vA >vte) in the auroral magnetosphere (2 - 4RE) with perpendicular scales on the order of the electron skin depth (c /ωpe) have a parallel electric field that, according to theory, is capable of nonlinearly accelerating suprathermal electrons to auroral energies. Unfortunately, due to space-time ambiguities of rocket and satellite measurements, it has not yet been possible to fully verify how Alfvén waves contribute to the production of accelerated electrons. To overcome the limitations of in situ spacecraft data, laboratory experiments have been carried out using the Large Plasma Device (LaPD), an NSF/DOE user facility at UCLA. An Electron Cyclotron Absorption (ECA) diagnostic has been developed to record the suprathermal parallel electron distribution function with 0.1% precision. The diagnostic records the electron distribution while inertial Alfvén waves simultaneously propagate through the plasma. Recent measurements have isolated oscillations of suprathermal electrons at the Alfvén wave frequency. Despite complications from boundary effects and the finite size of the experiment, a linear kinetic model has been produced that describes the experimental results. To our knowledge this is the first quantitative agreement between the measured and modeled linear response of suprathermal electrons to an inertial Alfvén wave. This verification of the linear physics is a necessary step before the nonlinear acceleration process can be isolated in future experiments. Presently, nonlinear effects cannot be detected because of limited Alfvén wave amplitudes. Ongoing work is focused on designing a higher-power antenna capable of efficiently launching larger-amplitude Alfvén waves with tunable perpendicular wavenumber and developing a theoretical understanding of the nonlinear acceleration process in LaPD plasma conditions. This material is

  19. Online beam energy measurement of Beijing electron positron collider II linear accelerator

    Science.gov (United States)

    Wang, S.; Iqbal, M.; Liu, R.; Chi, Y.

    2016-02-01

    This paper describes online beam energy measurement of Beijing Electron Positron Collider upgraded version II linear accelerator (linac) adequately. It presents the calculation formula, gives the error analysis in detail, discusses the realization in practice, and makes some verification. The method mentioned here measures the beam energy by acquiring the horizontal beam position with three beam position monitors (BPMs), which eliminates the effect of orbit fluctuation, and is much better than the one using the single BPM. The error analysis indicates that this online measurement has further potential usage such as a part of beam energy feedback system. The reliability of this method is also discussed and demonstrated in this paper.

  20. Detection methods of pulsed X-rays for transmission tomography with a linear accelerator

    International Nuclear Information System (INIS)

    Appropriate detection methods are studied for the development of a high energy tomograph using a linear accelerator for nondestructive testing of bulky objects. The aim is the selection of detectors adapted to a pulsed X-ray source and with a good behavior under X-ray radiations of several MeV. Performance of semiconductors (HgI2, Cl doped CdTe, GaAs, Bi12Ge020) and a scintillator (Bi4Ge3012) are examined. A prototype tomograph gave images that show the validity of detectors for analysis of medium size equipment such as a concrete drum of 60 cm in diameter

  1. Performance of Conduction Cooled Splittable Superconducting Magnet Package for Linear Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Kashikhin, Vladimire S. [Fermilab; Andreev, N. [Fermilab; Cheban, S. [Fermilab; DiMarco, J. [Fermilab; Kimura, N. [KEK, Tsukuba; Makarov, A. [Fermilab; Orlov, Y. [Fermilab; Poloubotko. V., Poloubotko. V. [Fermilab; Tartaglia, M. [Fermilab; Yamamoto, A. [KEK, Tsukuba

    2015-01-01

    New Linear Superconducting Accelerators need a superconducting magnet package installed inside SCRF Cryomodules to focus and steer electron or proton beams. A superconducting magnet package was designed and built as a collaborative effort of FNAL and KEK. The magnet package includes one quadrupole, and two dipole windings. It has a splittable in the vertical plane configuration, and features for conduction cooling. The magnet was successfully tested at room temperature, in a liquid He bath, and in a conduction cooling experiment. The paper describes the design and test results including: magnet cooling, training, and magnetic measurements by rotational coils. The effects of superconductor and iron yoke magnetization, hysteresis, and fringe fields are discussed.

  2. Power vircathor based on iron-less linear induction electron accelerator

    International Nuclear Information System (INIS)

    The design of the power vircathor, representing a UHF generator on the virtual cathode basis, is described. The power vircathor is realized for the first time on the basis of an iron-less linear induction accelerator on the radial forming lines. The vircathor contains the coaxial cathode and anode, the gas-controlled discharge and the inductors unit. The results of computer modeling of the vircathor geometry and its experimental optimization are presented. The following vircathor parameters: the cathode current of 35 kA, the UHF pulse duration of 18 ns and the peak capacity above 500 MW are obtained in the course of the performed experiments

  3. Measurement and analysis of the electric field radiation in pulsed power system of linear induction accelerator

    International Nuclear Information System (INIS)

    The close of high voltage switch in pulsed power system of linear induction accelerator often radiates strong transient electric field, which may influence ambient sensitive electric equipment, signals and performance of other instruments, etc. By performing gridded measurement around the Marx generator, the general distribution law and basic characters of electric field radiation are summarized. The current signal of the discharge circuit is also measured, which demonstrates that the current and the radiated electric field both have a resonance frequency about 150 kHz, and contain much higher frequency components. (authors)

  4. Coherent radiation from high-current electron beams of linear accelerators and its applications

    Science.gov (United States)

    Okuda, Shuichi; Takanaka, Makoto; Nakamura, Mitsumi; Kato, Ryukou; Takahashi, Toshiharu; Nam, Soon-Kwon; Taniguchi, Ryouichi; Kojima, Takao

    2006-08-01

    The characteristics of the far-infrared light source using the coherent radiation emitted from a high-energy short electron bunch have been investigated. The coherent radiation has a continuous spectrum in a submillimeter to millimeter wavelength range and the brightness is relatively high. The spectrum of the radiation is determined by the longitudinal form factor of the electron bunch. The operational conditions of a high-current linear accelerator have been optimized using an electron bunch shape monitor. The coherent transition radiation light source has been applied to absorption spectroscopy for liquid water and to an imaging experiment for a leaf of rose.

  5. Electron optics properties of field emission tetrode guns and of a linear accelerator

    International Nuclear Information System (INIS)

    Field emission gun, optical properties are recalled; the different methods to get the electrostatic potential are recalled too, more specifically the finite element method. The electron optics properties of the field emission tetrode guns are studied; specifically, the source image position has been studied as a function of the electric parameters; the spherical observation coefficients together with the source image radius as a function of electric and geometric parameters. A study of the same parameters in the case of a field emission tetrode gun followed by a linear accelerator is given

  6. Design, fabrication and testing of a large cylindrical vacuum vessel for proton linear accelerator

    International Nuclear Information System (INIS)

    The paper deals with engineering design, fabrication, copper plating and vacuum design and leak testing of the first prototype segment of Alveraz type drift tube Proton Linear Accelerator (DTL) being developed at CAT. The prototype drift tube linac segment is a long horizontal cylindrical vacuum vessel. The cylindrical cavity is internally machined and copper plated from inside and operates at 202 MHz (RF) with a vacuum better than 1 x 10-6 mbar. There are 34 openings provided for vacuum pumps, RF input and monitoring loops, piston tuners etc. and a large openings for insertions of drift tubes from top of the tank. (author)

  7. Cavity control system advanced modeling and simulations for TESLA linear accelerator and free electron laser

    Science.gov (United States)

    Czarski, Tomasz; Romaniuk, Ryszard S.; Pozniak, Krzysztof T.; Simrock, Stefan

    2004-07-01

    The cavity control system for the TESLA -- TeV-Energy Superconducting Linear Accelerator project is initially introduced. The elementary analysis of the cavity resonator on RF (radio frequency) level and low level frequency with signal and power considerations is presented. For the field vector detection the digital signal processing is proposed. The electromechanical model concerning Lorentz force detuning is applied for analyzing the basic features of the system performance. For multiple cavities driven by one klystron the field vector sum control is considered. Simulink model implementation is developed to explore the feedback and feed-forward system operation and some experimental results for signals and power considerations are presented.

  8. The system of constant current focus klystron KIU-37 master pulsed microwave generator electron linear accelerator

    International Nuclear Information System (INIS)

    In order to ensure long-term stability of beam parameters of linear accelerators is working on stabilizing the excitation of high-power systems. At this stage the solution of the problem, developed and applied in practice stabilization focusing coil current klystron KIU-37 to eliminate the dependence of the output power from the mains supply voltage fluctuations and other destabilizing factors. Its use has provided the stability of the output current in the range of +-0.5% with changes in the supply voltage +-10%, which, in turn, made it possible to significantly increase the long term stability of parameters of the excitation signal

  9. High energy X-ray CT system using a linear accelerator for automobile parts inspection

    International Nuclear Information System (INIS)

    A high energy X-ray CT system (maximum photon energy: 0.95 MeV) has been developed for industrial use. This system employs a linear accelerator as an X-ray source. It is able to image the cross section of automobile parts and can be applied to a solidification analysis study of the cylinder head in an automobile. This paper describes the features of the system and application results which can be related to solidification analysis of the cylinder head when fabricated from an aluminum casting. Some cross-sectional images are also presented as evidence for nondestructive inspection of automobile parts. (orig.)

  10. Measurements of Neutron Induced Cross Sections at the Oak Ridge Electron Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Guber, K.H.; Harvey, J.A.; Hill, N.W.; Koehler, P.E.; Leal, L.C.; Sayer, R.O.; Spencer, R.R.

    1999-09-20

    We have used the Oak Ridge Electron Linear Accelerator (ORELA) to measure neutron total and the fission cross sections of 233U in the energy range from 0.36 eV to ~700 keV. We report average fission and total cross sections. Also, we measured the neutron total cross sections of 27Al and Natural chlorine as well as the capture cross section of Al over an energy range from 100 eV up to about 400 keV.

  11. Method for pulse to pulse dose reproducibility applied to electron linear accelerators

    International Nuclear Information System (INIS)

    An original method for obtaining programmed beam single shots and pulse trains with programmed pulse number, pulse repetition frequency, pulse duration and pulse dose is presented. It is particularly useful for automatic control of absorbed dose rate level, irradiation process control as well as in pulse radiolysis studies, single pulse dose measurement or for research experiments where pulse-to-pulse dose reproducibility is required. This method is applied to the electron linear accelerators, ALIN-10 of 6.23 MeV and 82 W and ALID-7, of 5.5 MeV and 670 W, built in NILPRP. In order to implement this method, the accelerator triggering system (ATS) consists of two branches: the gun branch and the magnetron branch. ATS, which synchronizes all the system units, delivers trigger pulses at a programmed repetition rate (up to 250 pulses/s) to the gun (80 kV, 10 A and 4 ms) and magnetron (45 kV, 100 A, and 4 ms).The accelerated electron beam existence is determined by the electron gun and magnetron pulses overlapping. The method consists in controlling the overlapping of pulses in order to deliver the beam in the desired sequence. This control is implemented by a discrete pulse position modulation of gun and/or magnetron pulses. The instabilities of the gun and magnetron transient regimes are avoided by operating the accelerator with no accelerated beam for a certain time. At the operator 'beam start' command, the ATS controls electron gun and magnetron pulses overlapping and the linac beam is generated. The pulse-to-pulse absorbed dose variation is thus considerably reduced. Programmed absorbed dose, irradiation time, beam pulse number or other external events may interrupt the coincidence between the gun and magnetron pulses. Slow absorbed dose variation is compensated by the control of the pulse duration and repetition frequency. Two methods are reported in the electron linear accelerators' development for obtaining the pulse to pulse dose reproducibility: the method

  12. Successful Application of Neutron Bubble Detectors in Neutron Dose Monitoring for Primus-M Election Linear Accelerators

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Neutrons produced by 10 MeV medical electronic linear accelerators used for radiotherapy treatments may be harmful for medical personnel and patients. These neutrons are generated by the photon-induced

  13. Linear vs. nonlinear acceleration in plasma turbulence. I. Global versus local measures

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Sanjoy [Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland 20723 (United States); Parashar, Tulasi N. [University of Delaware, Newark, Delaware 19716 (United States)

    2015-04-15

    Magnetized turbulent plasmas are generally characterized as strongly or weakly turbulent based on the average relative strengths of the linear and nonlinear terms. While this description is useful, it does not represent the full picture and can be misleading. We study the variation of linear and nonlinear accelerations in the Fourier space of a magnetohydrodynamic system with a mean magnetic field and broad selection of initial states and plasma parameters. We show that the local picture can show significant departures from what is expected from the general global picture. We find that high cross helicity systems that are traditionally believed to have relatively weaker nonlinearities, compared to low cross helicity systems, can show strong nonlinearities in parts of the Fourier space that are orthogonal to the mean magnetic field direction. In some cases, these nonlinearities can exceed in strength the level of nonlinearities recovered from low cross helicity systems.

  14. Second order particle motion equations and linear chromaticity calculation in accelerator rings

    International Nuclear Information System (INIS)

    The first part of this note presents a thorough study on the second order particle motion equations, both in continuous field and in hard edges, with emphasis put on the latter. Having quite general conditions and strict mathematical treatments, it provides a sound ground from which many problems can be solved without fear of being misled. Then the linear CHR calculation is inspected, the first step being a general analytical expression of the transverse oscillation phase increment due to a small disturbance. The expression for the CHR is then readily obtained since tune is the transverse oscillation number per turn and the CHR is the linear dependence of the tune on particle energy/momentum deviation. The last part gives the formulae for practical CHR calculation, which are general enough to include almost all the magnet types commonly used in various accelerator rings and are simpler than can be found elsewhere

  15. A GPU-accelerated toolbox for the solutions of systems of linear equations

    Science.gov (United States)

    Humphrey, John R., Jr.; Paolini, Aaron L.; Price, Daniel K.; Kelmelis, Eric J.

    2009-05-01

    The modern graphics processing unit (GPU) found in many off-the shelf personal computers is a very high performance computing engine that often goes unutilized. The tremendous computing power coupled with reasonable pricing has made the GPU a topic of interest in recent research. An application for such power would be the solution to large systems of linear equations. Two popular solution domains are direct solution, via the LU decomposition, and iterative solution, via a solver such as the Generalized Method of Residuals (GMRES). Our research focuses on the acceleration of such processes, utilizing the latest in GPU technologies. We show performance that exceeds that of a standard computer by an order of magnitude, thus significantly reducing the run time of the numerous applications that depend on the solution of a set of linear equations.

  16. Synchronization of multiple magnetically switched modules to power linear induction adder accelerators

    International Nuclear Information System (INIS)

    In applications where multiple magnetic modulators are used to drive a single Linear Induction Voltage Adder (LIVA) or Linear Accelerator (LINAC), it is essential that the outputs of the modulators by synchronized. Output rise times are typically in the 10ns to 20ns range, often making it necessary to synchronize to within less than 1ns. Microprocessor and electronic feedback schemes have been developed and demonstrated that achieve the required level of synchronization, however, they are sophisticated and potentially complex. In a quest for simplicity, this work seeks to determine the achievable level of modulator to modulator timing jitter that can be obtained with simple design practices and passive techniques. Sources of output pulse time jitter in magnetic modulators are reviewed and some basic modulator design principles that can be used to minimize the intrinsic time jitter between modulators are discussed. A novel technique for passive synchronization is presented

  17. Varian 23EX直线加速器真空电源故障处理%Troubleshooting for vacuum power in Varian 23EX linear accelerator

    Institute of Scientific and Technical Information of China (English)

    王少丹

    2012-01-01

    The vacuum system is an important part of the linear accelerator and it has a high failure rate.This article briefly describes the basic structure and working principle of the Varian 23EX linear accelerator vacuum system,analyzes the common interlock signal of vacuum system.For a case of failure,the reason investigation process and troubleshooting of the linear accelerator vacuum power is described in detail.The author summarizes the skills and qualities that a clinical engineer should have in the routine maintenance of the linear accelerator.%真空系统是直线加速器的重要组成部分,故障率较高。通过介绍Varian23EX直线加速器真空系统的基本构成和工作原理、对真空系统常见的联锁信号进行简要分析,以及就一例特殊的直线加速器真空电源故障现象、原因排查过程及故障解决的描述,总结了临床工程师在直线加速器的日常维护中应具备的技能和素质。

  18. Mathematical representation of photon beam out-put factors for tele-isotopic machines and linear accelerators

    International Nuclear Information System (INIS)

    An attempt had been made to generalise the concepts involved in the dose output measurement of tele cobalt machines and linear accelerators. In India, cobalt therapy machines are in mainstay for use in radiotherapy and problems in exposure rate measurement are immense. The paper analyses the output factors for different models of cobalt machines and accelerators. (author)

  19. Experimental facilities for quasimonochromatic polarized photon beam production in the Kharkov linear accelerator

    International Nuclear Information System (INIS)

    A set of equipment designed to obtain quasimonochromatic linearly polarized high-energy photons in a linear accelerator is described. A beam of quasimonochromatic linearly polarized photons was obtained by coherent bremsstrahlung of electrons in diamond monocrystals. The 1.4 GeV electron beam with a divergence of approximately 10-4 rad and intensity of 0.2-0.3 μA strikes monocrystalline diamond targets having a thickness of 0.3 and 0.08 mm. The targets are installed in a qoniometric device with an angle reading accuracy of 5x10-5 rad. A beam of linearly polarized photons with a collimation angle of approximately 10-4 rad shaped with the help of adjustable lead-baffled collimators strikes a liquid-hydrogen target located at the focal point of two magnetic spectrometers. The nuclear reaction products are analyzed in momentum and detected by scintillation counter telescopes. The total photon flux with an intensity from 108-1010 equiv. γ-quantum/s and corresponding polarization of 90-50% is measured by means of Wilson-type or secondary-emission quantometers

  20. Optimization of a neutron transmission beamline applied to materials science for the CAB linear accelerator

    International Nuclear Information System (INIS)

    The Neutrons and Reactors Laboratory (NYR) of CAB (Centro Atomico Bariloche) is equipped with a linear electron accelerator (LINAC - Linear particle accelerator). This LINAC is used as a neutron source from which two beams are extracted to perform neutron transmission and dispersion experiments. Through these experiments, structural and dynamic properties of materials can be studied. The neutron transmission experiments consist in a collimated neutron beam which interacts with a sample and a detector behind the sample. Important information about the microstructural characteristics of the material can be obtained from the comparison between neutron spectra before and after the interaction with the sample. In the NYR Laboratory, cylindrical samples of one inch of diameter have been traditionally studied. Nonetheless, there is a great motivation for doing systematic research on smaller and with different geometries samples; particularly sheets and samples for tensile tests. Hence, in the NYR Laboratory it has been considered the possibility of incorporating a neutron guide into the existent transmission line. According to all mentioned above, the main objective of this work consisted in the optimization of the flight transmission tube optics of neutrons. This optimization not only improved the existent line but also contributed to an election criterion for the neutron guide acquisition.

  1. Monte Carlo model of the female RANDO phantom irradiation with an Elekta Precise linear accelerator

    International Nuclear Information System (INIS)

    Anthropomorphic laboratory phantoms are a very useful aid in radiotherapy treatment planning. Such phantoms allow estimating detailed mapping of dose distribution. The phantom utilized in this work is the female RANDO Phantom, which represents a 163 cm tall and 54 kg figure that does not have arms or legs. It is constructed with a natural human skeleton which is cast inside soft tissue-simulating material and lung-simulating material. A set of computer tomography images of the RANDO Phantom was obtained and segmented. Once the slices were segmented and the pixel intensities related with the phantom materials, they were input to a Matlab algorithm developed by the authors and validated in previous works, which uses the CT slices to build up a three-dimensional numerical voxelized phantom by pixel and material identification, and writes it in the MCNP5 input deck format utilizing the lattice card, together with an MCNP5 model for the Elekta Precise Linear Accelerator. The Linear Accelerator model has also been also validated in previous works. The simulation results in mapping of dose distribution inside the phantom, utilizing the MCNP5 tool FMESH, superimposed mesh tally, which allows registering the results over the problem geometry.

  2. Characterisation of mixed radiation field produced in medical linear accelerators using foil activation technique

    International Nuclear Information System (INIS)

    The photon spectrum produced in medical linear accelerators and used for tumour therapy was measured using foil activation techniques in this work. The machine employed is the linear medical accelerator SL-25, Philips, installed at the Walsgrave Hospital Radiotherapy Centre in Coventry, U.K. A number of foil sets, with different energy thresholds were irradiated at different points inside a 400 mm by 400 mm treatment field at a nominal dose rate of 400 MU (∼4 Gy/min), and photon energy of 25 MV at the machine's isocentre. The induced activity of each foil was measured using a NaI(Tl) detector and a PC-based multichannel analyzer. The spectrum of the photons was unfolded using the computer code LOUHI82. The relative changes in the spectrum across the treatment field, were also measured using foils placed at 2.5deg, 5deg, 10deg and 13deg on both sides of the central axis of the treatment field. In order to estimate the extra dose received by the patient due to the neutron component, the neutron flux distribution at different points across the treatment field was measured using gold foils. The results and implications are discussed. (author)

  3. Evaluation of a new IR-guided system for mechanical QA of linear accelerators

    International Nuclear Information System (INIS)

    The authors report the development of a new procedure for mechanical quality assurance of linear accelerators using an infrared-guided system. The system consists of an infrared (IR) camera and an IR-reflective marker that can be attached to a gantry, a collimator, or a treatment table. The trace of this marker can be obtained in three dimensions (3D) for a full or partial rotation of the mechanical devices. The software is written to localize rotational axes of the gantry, collimator, and the treatment table based on the marker traces. The separation of these axes characterizes the size of the sphere defining the mechanical isocenter. Additional information on anomalies in gantry movement such as degree of gantry sag and hysteresis can also be obtained. An intrinsic uncertainty of the system to localize rotational axis is 0.35 mm or less. Tests on a linear accelerator demonstrated the ability of this system to detect the separation between rotational axes of less than 1 mm and to confirm orthogonality of the planes of gantry, collimator, and table rotation.

  4. Prostate stereotactic ablative body radiotherapy using a standard linear accelerator: Toxicity, biochemical, and pathological outcomes

    International Nuclear Information System (INIS)

    Background and purpose: Biological dose escalation through stereotactic ablative radiotherapy (SABR) holds promise of improved patient convenience, system capacity and tumor control with decreased cost and side effects. The objectives are to report the toxicities, biochemical and pathologic outcomes of this prospective study. Materials and methods: A phase I/II study was performed where low risk localized prostate cancer received SABR 35 Gy in 5 fractions, once weekly on standard linear accelerators. Common Terminology Criteria for Adverse Events v3.0 and Radiation Therapy Oncology Group late morbidity scores were used to assess acute and late toxicities, respectively. Biochemical control (BC) was defined by the Phoenix definition. Results: As of May 2012, 84 patients have completed treatment with a median follow-up of 55 months (range 13–68 months). Median age was 67 years and median PSA was 5.3 ng/ml. The following toxicities were observed: acute grade 3+: 0% gastrointestinal (GI), 1% genitourinary (GU), 0% fatigue; late grade 3+: 1% GI, 1% GU. Ninety-six percent were biopsy negative post-treatment. The 5-year BC was 98%. Conclusions: This novel technique employing standard linear accelerators to deliver an extreme hypofractionated schedule of radiotherapy is feasible, well tolerated and shows excellent pathologic and biochemical control

  5. A New Linear Inductive Voltage Adder Driver for the Saturn Accelerator

    CERN Document Server

    Mazarakis, M G; Struve, K W; Long, F W

    2000-01-01

    Saturn is a dual-purpose accelerator. It can be operated as a large-area flash x-ray source for simulation testing or as a Z-pinch driver especially for K-line x-ray production. In the first mode, the accelerator is fitted with three concentric-ring 2-MV electron diodes, while in the Z-pinch mode the current of all the modules is combined via a post-hole convolute arrangement and driven through a cylindrical array of very fine wires. We present here a point design for a new Saturn class driver based on a number of linear inductive voltage adders connected in parallel. A technology recently implemented at the Institute of High Current Electronics in Tomsk (Russia) is being utilized[1]. In the present design we eliminate Marx generators and pulse-forming networks. Each inductive voltage adder cavity is directly fed by a number of fast 100-kV small-size capacitors arranged in a circular array around each accelerating gap. The number of capacitors connected in parallel to each cavity defines the total maximum cur...

  6. Presentations from the Second ORION Workshop, Stanford Linear Accelerator Center, February 18-20, 2003

    International Nuclear Information System (INIS)

    ORION will be a dedicated user facility available for experimental research in plasma and laser acceleration of particles, beam-plasma physics, ultra-short pulse electron and radiation sources, and potentially laboratory astrophysics. It will bring together a diverse collection of researchers motivated to solve some of the most complex and fascinating problems in these fields. The ORION Facility will be based on the Next Linear Collider Test Accelerator (NLCTA), an existing accelerator at SLAC capable of producing 60 to 350 MeV electron beams. The NLCTA will be augmented with a new photo-injector source, two experimental halls, extraction beamlines, a user laser room, and a data acquisition area. Facility construction is anticipated to start in October 2003, and first beam for experiments is planned for 2005. A central goal of ORION is to provide a facility responsive to the research needs of its users. The workshop's purpose is to explore the range of experiments envisioned by potential users and review the types of beams available and the desired beam parameters. This workshop is an opportunity for the research community to provide input on the facility's test beams, layout, shared diagnostic equipment, simulation and computing capabilities, and user support infrastructure. Results from the workshop will go into determining the facility's design as well as help the SLAC management plan for future user needs on the site once operations begin

  7. 7.5 MeV High Average Power Linear Accelerator System for Food Irradiation Applications

    International Nuclear Information System (INIS)

    In December 2004 the US Food and Drug Administration (FDA) approved the use of 7.5 MeV X-rays for irradiation of food products. The increased efficiency for treatment at 7.5 MeV (versus the previous maximum allowable X-ray energy of 5 MeV) will have a significant impact on processing rates and, therefore, reduce the per-package cost of irradiation using X-rays. Titan Pulse Sciences Division is developing a new food irradiation system based on this ruling. The irradiation system incorporates a 7.5 MeV electron linear accelerator (linac) that is capable of 100 kW average power. A tantalum converter is positioned close to the exit window of the scan horn. The linac is an RF standing waveguide structure based on a 5 MeV accelerator that is used for X-ray processing of food products. The linac is powered by a 1300 MHz (L-Band) klystron tube. The electrical drive for the klystron is a solid state modulator that uses inductive energy store and solid-state opening switches. The system is designed to operate 7000 hours per year. Keywords: Rf Accelerator, Solid state modulator, X-ray processing

  8. Consequences of bounds on longitudinal emittance growth for the design of recirculating linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Berg, J. S. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2015-05-03

    Recirculating linear accelerators (RLAs) are a cost-effective method for the acceleration of muons for a muon collider in energy ranges from a couple GeV to a few 10s of GeV. Muon beams generally have longitudinal emittances that are large for the RF frequency that is used, and it is important to limit the growth of that longitudinal emittance. This has particular consequences for the arc design of the RLAs. I estimate the longitudinal emittance growth in an RLA arising from the RF nonlinearity. Given an emittance growth limitation and other design parameters, one can then compute the maximum momentum compaction in the arcs. I describe how to obtain an approximate arc design satisfying these requirements based on the deisgn in [1]. Longitudinal dynamics also determine the energy spread in the beam, and this has consequences on the transverse phase advance in the linac. This in turn has consequences for the arc design due to the need to match beta functions. I combine these considerations to discuss design parameters for the acceleration of muons for a collider in an RLA from 5 to 63 GeV.

  9. Occupational radiation protection around medical linear accelerators: measurements and semi-analytical approaches

    International Nuclear Information System (INIS)

    Full text: X-rays produced by high-energy (larger than 6 MeV) medical electron linear accelerators create secondary neutron radiation fields mainly by photonuclear reactions inside the materials of the accelerator head, the patient and the walls of the therapy room. Numerous papers were devoted to the study of neutron production in medical linear accelerators and resulting decay of activation products. However, data associated to doses delivered to workers in treatment conditions are scarce. In France, there are more than 350 external radiotherapy facilities representing almost all types of techniques and designs. IRSN carried out a measurement campaign in order to investigate the variation of the occupational dose according the different encountered situations. Six installations were investigated, associated with the main manufacturers (Varian, Elekta, General Electrics, Siemens), for several nominal energies, conventional and IMRT techniques, and bunker designs. Measurements were carried out separately for neutron and photon radiation fields, and for radiation associated with the decay of the activation products, by means of radiometers, tissue-equivalent proportional counters and spectrometers (neutron and photon spectrometry). They were performed at the positions occupied by the workers, i.e. outside the bunker during treatments, inside between treatments. Measurements have been compared to published data. In addition, semi-empirical analytical approaches recommended by international protocols were used to estimate doses inside and outside the bunkers. The results obtained by both approaches were compared and analysed. The annual occupational effective dose was estimated to about 1 mSv, including more than 50 % associated with the decay of activation products and less than 10 % due to direct exposure to leakage neutrons produced during treatments. (author)

  10. Statistical analysis of operating efficiency and failures of a medical linear accelerator for ten years

    International Nuclear Information System (INIS)

    To improve the management of a medical linear accelerator, the records of operational failures of a Varian CL2100C over a ten year period were retrospectively analyzed. The failures were classified according to the involved functional subunits, with each class rated into one of three levels depending on the operational conditions. The relationships between the failure rate and working ratio and between the failure rate and outside temperature were investigated. In addition, the average life time of the main part and the operating efficiency over the last 4 years were analyzed. Among the recorded failures (total 587 failures), the most frequent failure was observed in the parts related with the collimation system, including the monitor chamber, which accounted for 20% of all failures. With regard to the operational conditions, 2nd level of failures, which temporally interrupted treatments, were the most frequent. Third level of failures, which interrupted treatment for more than several hours, were mostly caused by the accelerating subunit. The number of failures was increased with number of treatments and operating time. The average life-times of the Klystron and Thyratron became shorter as the working ratio increased, and were 42 and 83% of the expected values, respectively. The operating efficiency was maintained at 95% or higher, but this value slightly decreased. There was no significant correlation between the number of failures and the outside temperature. The maintenance of detailed equipment problems and failures records over a long period of time can provide good knowledge of equipment function as well as the capability of predicting future failure. More rigorous equipment maintenance is required for old medical linear accelerators for the advanced avoidance of serious failure and to improve the quality of patient treatment

  11. Preliminary Safety Analysis Report (PSAR), The NSLS 200 MeV Linear Electron Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Blumberg, L.N.; Ackerman, A.I.; Dickinson, T.; Heese, R.N.; Larson, R.A.; Neuls, C.W.; Pjerov, S.; Sheehan, J.F.

    1993-06-15

    The radiological, fire and electrical hazards posed by a 200 MeV electron Linear Accelerator, which the NSLS Department will install and commission within a newly assembled structure, are addressed in this Preliminary Safety Analysis Report. Although it is clear that this accelerator is intended to be the injector for a future experimental facility, we address only the Linac in the present PSAR since neither the final design nor the operating characteristics of the experimental facility are known at the present time. The fire detection and control system to be installed in the building is judged to be completely adequate in terms of the marginal hazard presented - no combustible materials other than the usual cabling associated with such a facility have been identified. Likewise, electrical hazards associated with power supplies for the beam transport magnets and accelerator components such as the accelerator klystrons and electron gun are classified as marginal in terms of potential personnel injury, cost of equipment lost, program downtime and public impact perceptions as defined in the BNL Environmental Safety and Health Manual and the probability of occurrence is deemed to be remote. No unusual features have been identified for the power supplies or electrical distribution system, and normal and customary electrical safety standards as practiced throughout the NSLS complex and the Laboratory are specified in this report. The radiation safety hazards are similarly judged to be marginal in terms of probability of occurrence and potential injury consequences since, for the low intensity operation proposed - a factor of 25 less than the maximum Linac capability specified by the vendor - the average beam power is only 0.4 watts. The shielding specifications given in this report will give adequate protection to both the general public and nonradiation workers in areas adjacent to the building as well as radiation workers within the controlled access building.

  12. Noninterceptive method to measure longitudinal Twiss parameters of a beam in a hadron linear accelerator using beam position monitors

    Science.gov (United States)

    Shishlo, A.; Aleksandrov, A.

    2013-06-01

    A new method of measuring of the rms longitudinal Twiss parameters of a beam in linear accelerators is presented. It is based on using sum signals from beam position monitors sensitive to the longitudinal charge distribution in the bunch. The applicability of the method is demonstrated on the superconducting section of the Oak Ridge Spallation Neutron Source linear accelerator. The results are compared to a direct measurement of the bunch longitudinal profiles using an interceptive bunch shape monitor in the linac warm section of the same accelerator. Limitations of the method are discussed. The method is fast and simple, and can be used to obtain the initial parameters for the longitudinal matching in linear accelerators where interceptive diagnostics are not desirable.

  13. Use of electron linear accelerators in medical radiation therapy. Overview report No. 1. physical characteristics. Technical report

    Energy Technology Data Exchange (ETDEWEB)

    1974-09-01

    The report is the first of a series of four overview reports prepared during the course of study regarding the use of electron linear accelerators in radiation therapy. The purpose of the study was to provide a data base which will assist BRH to decide whether the development of a performance standard concerning the radiation safety of medical linear accelerators is necessary, and if so, the priority which should be assigned to such a standard. The purpose of this report is to present an overview of the physical characteristics of electron linear accelerators used in medical radiation therapy. Particular attention is given to those physical characteristics and performance parameters which are related to delivery of a useful properly controlled prescription dose of radiation to the patient and to delivery of a potentially harmful dose of radiation to the patient, machine operator or others in the vicinity of the accelerator. (GRA)

  14. A dose-response curve for biodosimetry from a 6 MV electron linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lemos-Pinto, M.M.P.; Cadena, M.; Santos, N.; Fernandes, T.S.; Borges, E.; Amaral, A., E-mail: marcelazoo@yahoo.com.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear

    2015-10-15

    Biological dosimetry (biodosimetry) is based on the investigation of radiation-induced biological effects (biomarkers), mainly dicentric chromosomes, in order to correlate them with radiation dose. To interpret the dicentric score in terms of absorbed dose, a calibration curve is needed. Each curve should be constructed with respect to basic physical parameters, such as the type of ionizing radiation characterized by low or high linear energy transfer (LET) and dose rate. This study was designed to obtain dose calibration curves by scoring of dicentric chromosomes in peripheral blood lymphocytes irradiated in vitro with a 6 MV electron linear accelerator (Mevatron M, Siemens, USA). Two software programs, CABAS (Chromosomal Aberration Calculation Software) and Dose Estimate, were used to generate the curve. The two software programs are discussed; the results obtained were compared with each other and with other published low LET radiation curves. Both software programs resulted in identical linear and quadratic terms for the curve presented here, which was in good agreement with published curves for similar radiation quality and dose rates. (author)

  15. A dose-response curve for biodosimetry from a 6 MV electron linear accelerator

    International Nuclear Information System (INIS)

    Biological dosimetry (biodosimetry) is based on the investigation of radiation-induced biological effects (biomarkers), mainly dicentric chromosomes, in order to correlate them with radiation dose. To interpret the dicentric score in terms of absorbed dose, a calibration curve is needed. Each curve should be constructed with respect to basic physical parameters, such as the type of ionizing radiation characterized by low or high linear energy transfer (LET) and dose rate. This study was designed to obtain dose calibration curves by scoring of dicentric chromosomes in peripheral blood lymphocytes irradiated in vitro with a 6 MV electron linear accelerator (Mevatron M, Siemens, USA). Two software programs, CABAS (Chromosomal Aberration Calculation Software) and Dose Estimate, were used to generate the curve. The two software programs are discussed; the results obtained were compared with each other and with other published low LET radiation curves. Both software programs resulted in identical linear and quadratic terms for the curve presented here, which was in good agreement with published curves for similar radiation quality and dose rates. (author)

  16. Design and evaluation for the shielding system of the 9 MeV travelling wave linear electron accelerator

    International Nuclear Information System (INIS)

    The authors use EGS4 code, a generally known Monte Carlo computer simulation package, to carry out the simulation analysis of the radiation dose distribution around the head shielding system and inside the accelerator hall of the 9 MeV travelling wave linear electron accelerator. The accelerator is used for the large container inspecting system. The comparison of experience formulae evaluation and practical data was made. The results show that, at the main reference points in the accelerator hall, the dose calculated by EEG's is well coincided with the results measured. It serves as a good example for flexible application of EGS4

  17. Experimental investigations of the neutron contamination in high-energy photon fields at medical linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Brunckhorst, Elin

    2009-02-26

    The scope of this thesis was to develop a device for the detection of the photoneutron dose inside the high-energy photon field. The photoneutron contamination of a Siemens PRIMUS linear accelerator was investigated in detail in its 15 MV photon mode. The experimental examinations were performed with three ionisation chambers (a tissue equivalent chamber, a magnesium chamber and a {sup 10}B-coated magnesium chamber) and two types of thermoluminescence detectors (enriched with {sup 6}Li and {sup 7}Li, respectively). The detectors have different sensitivities to photons and neutrons and their combination allows the dose separation in a mixed neutron/photon field. The application of the ionisation chamber system, as well as the present TLD system for photoneutron detection in high-energy photon beams is a new approach. The TLD neutron sensitivity was found to be too low for a measurement inside the open photon field and the further investigation focused on the ionisation chambers. The three ionisation chambers were calibrated at different photon and neutron sources and a the borated magnesium chamber showed a very high response to thermal neutrons. For a cross check of the calibration, the three chambers were also used for dose separation of a boron neutron capture therapy beam where the exact determination of the thermal neutron dose is essential. Very accurate results were achieved for the thermal neutron dose component. At the linear accelerator the chamber system was reduced to a paired chamber system utilising the two magnesium chambers, since the fast neutron component was to small to be separated. The neutron calibration of the three chambers could not be applied, instead a conversion of measured thermal neutron signal by the borated chamber to Monte Carlo simulated total neutron dose was performed. Measurements for open fields in solid water and liquid water were performed with the paired chamber system. In larger depths the neutron dose could be determined

  18. Experimental investigations of the neutron contamination in high-energy photon fields at medical linear accelerators

    International Nuclear Information System (INIS)

    The scope of this thesis was to develop a device for the detection of the photoneutron dose inside the high-energy photon field. The photoneutron contamination of a Siemens PRIMUS linear accelerator was investigated in detail in its 15 MV photon mode. The experimental examinations were performed with three ionisation chambers (a tissue equivalent chamber, a magnesium chamber and a 10B-coated magnesium chamber) and two types of thermoluminescence detectors (enriched with 6Li and 7Li, respectively). The detectors have different sensitivities to photons and neutrons and their combination allows the dose separation in a mixed neutron/photon field. The application of the ionisation chamber system, as well as the present TLD system for photoneutron detection in high-energy photon beams is a new approach. The TLD neutron sensitivity was found to be too low for a measurement inside the open photon field and the further investigation focused on the ionisation chambers. The three ionisation chambers were calibrated at different photon and neutron sources and a the borated magnesium chamber showed a very high response to thermal neutrons. For a cross check of the calibration, the three chambers were also used for dose separation of a boron neutron capture therapy beam where the exact determination of the thermal neutron dose is essential. Very accurate results were achieved for the thermal neutron dose component. At the linear accelerator the chamber system was reduced to a paired chamber system utilising the two magnesium chambers, since the fast neutron component was to small to be separated. The neutron calibration of the three chambers could not be applied, instead a conversion of measured thermal neutron signal by the borated chamber to Monte Carlo simulated total neutron dose was performed. Measurements for open fields in solid water and liquid water were performed with the paired chamber system. In larger depths the neutron dose could be determined with an uncertainty

  19. Commissioning and early experience with a new-generation low-energy linear accelerator with advanced delivery and imaging functionalities

    International Nuclear Information System (INIS)

    A new-generation low-energy linear accelerator (UNIQUE) was introduced in the clinical arena during 2009 by Varian Medical Systems. The world's first UNIQUE was installed at Oncology Institute of Southern Switzerland and put into clinical operation in June 2010. The aim of the present contribution was to report experience about its commissioning and first year results from clinical operation. Commissioning data, beam characteristics and the modeling into the treatment planning system were summarized. Imaging system of UNIQUE included a 2D-2D matching capability and tests were performed to identify system repositioning capability. Finally, since the system is capable of delivering volumetric modulated arc therapy with RapidArc, a summary of the tests performed for such modality to assess its performance in preclinical settings and during clinical usage was included. Isocenter virtual diameter was measured as less than 0.2 mm. Observed accuracy of isocenter determination and repositioning for 2D-2D matching procedures in image guidance was <1.2 mm. Concerning reproducibility and stability over a period of 1 year, deviations from reference were found <0.3 ± 0.2% for linac output, <0.1% for homogeneity, similarly to symmetry. Rotational accuracy of the entire gantry-portal imager system showed a maximum deviation from nominal 0.0 of <1.2 mm. Pre treatment quality assurance of RapidArc plans resulted with a Gamma Agreement Index (fraction of points passing the gamma criteria) of 97.0 ± 1.6% on the first 182 arcs verified. The results of the commissioning tests and of the first period of clinical operation, resulted meeting specifications and having good margins respect to tolerances. UNIQUE was put into operation for all delivery techniques; in particular, as shown by the pre-treatment quality assurance results, it enabled accurate and safe delivery of RapidArc plans

  20. A new linear inductive voltage adder driver for the Saturn Accelerator

    International Nuclear Information System (INIS)

    Saturn is a dual-purpose accelerator. It can be operated as a large-area flash x-ray source for simulation testing or as a Z-pinch driver especially for K-line x-ray production. In the first mode, the accelerator is fitted with three concentric-ring 2-MV electron diodes, while in the Z-pinch mode the current of all the modules is combined via a post-hole convolute arrangement and driven through a cylindrical array of very fine wires. We present here a point design for a new Saturn class driver based on a number of linear inductive voltage adders connected in parallel. A technology recently implemented at the Institute of High Current Electronics in Tomsk (Russia) is being utilized. In the present design we eliminate Marx generators and pulse-forming networks. Each inductive voltage adder cavity is directly fed by a number of fast 100-kV small-size capacitors arranged in a circular array around each accelerating gap. The number of capacitors connected in parallel to each cavity defines the total maximum current. By selecting low inductance switches, voltage pulses as short as 30-50-ns FWHM can be directly achieved. The voltage of each stage is low (100-200 kv). Many stages are required to achieve multi-megavolt accelerator output. However, since the length of each stage is very short (4-10 cm), accelerating gradients of higher than 1 MV/m can easily be obtained. The proposed new driver will be capable of delivering pulses of 15-MA, 36-TW, 1.2-MJ to the diode load, with a peak voltage of -2.2 MV and FWHM of 40-ns. And although its performance will exceed the presently utilized driver, its size and cost could be much smaller (approximately1/3). In addition, no liquid dielectrics like oil or deionized water will be required. Even elimination of ferromagnetic material (by using air-core cavities) is a possibility

  1. High intensity linear accelerator development topics for panel discussion on ''Nuclear Energy Research and Accelerators: Future Prospects''

    International Nuclear Information System (INIS)

    Two companion papers at this meeting have introduced the subject of high intensity linacs for materials research and for radioactive waste transmutation; Prof. Kaneko's paper ''Intense Proton Accelerator,'' and my paper ''Accelerator-Based Intense Neutron Source for Materials R ampersand D.'' I will expand on those remarks to briefly outline some of the extensive work that has been done at Los Alamos toward those two application areas, plus a third --- the production of tritium in an accelerator-based facility (APT--Accelerator Production of Tritium). 1 ref., 11 figs

  2. Dosimetry of the stereotactic radiosurgery with linear accelerators equipped with micro multi-blades collimators

    International Nuclear Information System (INIS)

    In this work, absorbed dose to water produced by the radiation beam of a clinical linear accelerator - CLINAC 600CTM (Varian), with a photon beam of 6 MV, were evaluated both theoretically and experimentally. This determination includes square and circular field configurations, the last one obtained with a micro multi leaf collimator - mMLC m3TM (Brain Lab). Theoretical evaluation was performed throughout Monte Carlo method. Experimental measurements of Percentage Depth Dose - PDD and derived Tissue Maximum Ratio - TMR curves from CLINAC 600C were validated by comparison with reference values as well as with measurements using different detectors. The results indicate local differences smaller than 5% and average differences smaller than 1,5% for each evaluated field, if they are compared to the previous commissioning values (made in 1999) and to the values of literature. Comparisons of ionization chamber and diode result in an average local difference of -0,6% for PDD measurements, and within 1% for lateral dose profiles, at depth, in the flat region. Diode provides measurements with better spatial resolution. Current output factors of open fields agree with reference values within 1,03% of discrepancy level. Current absorbed dose distributions in water are, now, considered reference values and allow characterization of this CLINAC for patient dose calculation. The photon spectra resulting from simulations with PENELOPE and MCNP codes agree approximately in 80% of the sampled points, in what average energies of (1,6 ± 0,3)MeV, with MCNP, and of (1,72 ± 0,08)MeV, with PENELOPE, are coincident. The created simple source model of the CLINAC 600C, using the PENELOPE code, allows one to calculate dose distributions in water, for open fields, with discrepancies of the order of ± 1,0% in dose and of ± 0,1 cm in position, if they are compared to experimental measurements. These values met the initial proposed criteria to validate the simulation model and guarantee its

  3. Transient enlargement of contrast uptake on MRI after linear accelerator (linac) stereotactic radiosurgery for brain metastases

    International Nuclear Information System (INIS)

    Purpose/Objective: With the increasing number of patients successfully treated with stereotactic radiosurgery for brain metastases, decision making after therapy based on follow-up imaging findings becomes more and more important. Magnetic resonance imaging (MRI) is the most sensitive means for follow-up studies. The objective of this study was to investigate the treatment outcome of our radiosurgery program and to describe the response of brain metastases to contrast-enhanced MRI after linear accelerator (linac) stereotactic radiosurgery and identify factors to distinguish among local control and local failure. Methods and Materials: Using serial MRI, we followed the course of 87 brain metastases in 48 consecutive patients treated between September 1996 and November 1997 with linac-based radiosurgery with 15-MV photons. Treatment planning was performed on an MR data cube. For spherical metastases, radiosurgery was delivered using a 9 noncoplanar arc technique with circular-shaped collimators. For irregularly shaped targets, radiosurgery was delivered using a manually driven multi-leaf collimator with a leaf width of 1.5 mm projected to the isocenter. Median radiosurgery dose was 20 Gy prescribed to the 80% isodose. Together with whole brain radiotherapy (20x2 Gy, 5/w), a median radiosurgical dose of 15 Gy was delivered. Median follow-up was 8 (range 2-36) months. Factors influencing local control and survival rates were analyzed with respect to MRI response, and Kaplan-Meier curves were calculated. Results: Actuarial local tumor control was 91% at one and two years. Patient survival at one and two years was 30% and 18%. Median survival was 9 months. During follow-up in 70 (81%) of the 87 treated metastases, the contrast-enhancing volumes on T1W images were stable or disappeared partly or completely. A transient enlargement of contrast-enhancing volumes was observed in 11 (12%) of the 87 lesions treated, while a progressive enlargement due to local treatment

  4. Pulsed electron gun and linear accelerator fitted with such a gun

    International Nuclear Information System (INIS)

    This invention relates to a pulsed electron gun comprising a leak-tight insulating tube closed at one end. A voltage of several tens of kilovolts is applied by cables to the ends of the tube. Among its other features this gun includes a conducting tube fitted inside an insulating tube on the same centre line, in a leak-tight manner to it. This conducting tube forms the grid support, and the bottom of the well so formed being closed by a conducting plate insulated from the conducting tube by an insulating ring, this plate becomes the support of the gun cathode. The grid support is part of the vacuum containment so formed. The electron linear accelerator comprising such a pulsed electron gun is also described

  5. The electron scattering facility at the Saclay 600 MeV linear accelerator

    International Nuclear Information System (INIS)

    An experimental set-up consisting of two high performance spectrometers is operating at the Saclay 600 MeV Linear Accelerator for electron scattering experiments with or without the detection of an emitted charged particle in coincidence. We give here the essential facts about the spectrometers, and the detection systems composed of multiwire proportional chambers and scintillation and Cerenkov counters. Very good rejection of background makes it possible to measure cross-sections as low as 10-4 nb sr-1 with 2.5 x 10-4 energy resolution in (e,e') experiments. For coincidence (e,e'p) measurements at 500 MeV incident electron energy, the lowest cross-section measured is 5 x 10-3 nb MeV-2 sr-2, and the missing energy resolution is 0.8 MeV. (orig.)

  6. An Electron Bunch Compression Scheme for a Superconducting Radio Frequency Linear Accelerator Driven Light Source

    International Nuclear Information System (INIS)

    We describe an electron bunch compression scheme suitable for use in a light source driven by a superconducting radio frequency (SRF) linac. The key feature is the use of a recirculating linac to perform the initial bunch compression. Phasing of the second pass beam through the linac is chosen to de-chirp the electron bunch prior to acceleration to the final energy in an SRF linac ('afterburner'). The final bunch compression is then done at maximum energy. This scheme has the potential to circumvent some of the most technically challenging aspects of current longitudinal matches; namely transporting a fully compressed, high peak current electron bunch through an extended SRF environment, the need for a RF harmonic linearizer and the need for a laser heater. Additional benefits include a substantial savings in capital and operational costs by efficiently using the available SRF gradient.

  7. Whole body electron therapy using the Philips SL75/10 linear accelerator

    International Nuclear Information System (INIS)

    Whole-body electron irradiation for mycosis fungoides is described, using a short distance multiple field technique for an electron beam of normal energy 4 Mev from a Philips SL75/10 linear accelerator, which minimised x-ray contamination. No special equipment or modifications were required. The energy of the electron beam was adjusted so that the 80% depth dose occurred at a depth of 13 mm. Treatment was given in four fractions per week. One quarter of the body surface was irradiated to 400 rads at each session. The dose rate at the patient was 100 rad/min. and the time for each treatment session was about 30 minutes. The groin, axillae and soles of the feet were treated by small electron fields to compensate for under dosage during the whole body irradiation. The eyes, fingernails and tonsils were protected by lead shields during treatment. (U.K.)

  8. High-Energy Beam Transport in the Hanford FMIT Linear Accelerator

    International Nuclear Information System (INIS)

    The High-Energy Beam Transport (HEBT) for the Hanford Fusion Materials Irradiation Test (FMIT) Facility's Linear Accelerator must transport a large emittance, high-current, high-power continuous duty deuteron beam with a large energy spread. Both periodic and nonperiodic systems have been designed to transport and shape the beam as required by the liquid lithium target. An energy spreader system distributes the Bragg Peak within the lithium. A beam spreader and a beam stop have been provided for tune-up purposes. Characterizing the beam will require extensions of beam diagnostics techniques and non-interceptive sensors. Provisions are being made in the facility for suspending the transport system from overhead supports

  9. Determination Of Output Factor For Photon Beam Of The Mitsubishi EXL-14 Linear Accelerator

    International Nuclear Information System (INIS)

    This paper describes the determination of output factor for 6 MV photon beam of The Mitsubishi EXL-14 linear accelerator teletherapy unit. Determination of percentage depth dose curve has been done using Wallhofer dosemeter at source to surface distance, SSD of 100 cm and field size of 10 cm x 10 cm. Measurement of output has been carried out using a 0.6 cc ionization chamber inside a water phantom at depth of 5 cm with source to surface distance, SSD of 100 cm for square fields ranging in size 4 cm x 4 cm up to 10 cm x 10 cm. Output for rectangular fields which equal to the equivalent square fields were also determined. The results obtained shows that the deviations of the output for 12 cm x 3 cm and 19 cm x 7 cm were higher than ±2% to the output of the equivalent square fields. (author)

  10. Dosimetry of a 3-5 MeV linear electron accelerator for radiation processing

    International Nuclear Information System (INIS)

    With the multiple uses of a 3-5 MeV linear electron accelerator of the Institute of Low Energy Nuclear Physics (Beijing Radiation Center) at Beijing Normal University, the dosimetry of the linac for radiation processing has been studied. The graphite and water calorimeters have been used for routine dosimeter calibrations and reference measurements of absorbed dose for 4 MeV electron beam. Under the same irradiation condition, the polymer-alanine/ESR film and RCD dosimeters were calibrated in order to be used for routine process control. The polymer-alanine/ESR film dosimeter was also used as a transfer dosimeter for both 60Co gamma rays and 4 MeV electron beam because of its good dosimetric properties. (author)

  11. Experimental investigation of a variant of an induction linear accelerator modulator part

    International Nuclear Information System (INIS)

    An induction linear accelerator ( LA) modulating part with magnetic elements for power comp ession and nonlinear pulse shaping circuit is considered. he coefficients of compression and energy transfer in the elements including choking coils designed on the base of of LIU-5/5000 inductors as well as ferrite rings ar experimentally determined. The performed experiments show that the compresssion coefficient in a microsec nd range constitutes 6-8. The energy transfer coefficient n the power range of several megawatts constitutes 0.8-U 9. Typical compression coefficients in the nanosecond r nge (up to 100 ns) constitutes 1.5-3. The energy transfe red from element to element may constitute of the order of 10 J. It is concluded that the analysis of the ob ained results permits to approach more rationally to the LA modulator design

  12. Assessment of X-ray output dose in the dose calculation of linear accelerators

    International Nuclear Information System (INIS)

    Many structural types of MLC (multiple-leaf collimator) are now introduced for linear accelerators and are important factors influencing the exposure dose to patients. In other words, the formula for dose calculation would differ depending on the type which, however, does not always require the different method of dose assessment for different MLC type. Rather, the assessment can be generalized and be applicable in any case of irradiation conditions when the concept of output factors is used. This article described the concept now recognized globally: The output factors consists from field factors and scatter factors, which are further divided in some factors attributable to the apparatus with MLC and irradiation object. The review also demonstrated the effectiveness of the concept by experiments using phantoms under various irradiation conditions. (K.H.)

  13. FEL system with the linear induction accelerator as the laser fusion reactor driver

    International Nuclear Information System (INIS)

    An FEL based energy driver for inertial confinement fusion (ICF) is proposed. Construction of such a driver becomes possible due to application of a novel FEL amplifier scheme - a multi-channel, multi-stage FEL amplifier with a diaphragm focusing line. The driving beam for the FEL amplifier is generated by the linear induction accelerator. The laser system operates at the radiation wavelength of 0.5 μm with the total energy of laser flash of 1.5 MJ, pulse duration of 4 ns and repetition rate of 40 pulses/s. Total efficiency (i.e. conversion efficiency of net electrical power to the radiation power) of the proposed system is equal to 12%. The brightness of the output radiation is 1022 W/cm2 sr. The scale and the cost of the FEL based energy driver are close to those of the heavy ion fusion driver. (orig.)

  14. Free-electron laser multiplex driven by a superconducting linear accelerator.

    Science.gov (United States)

    Plath, Tim; Amstutz, Philipp; Bödewadt, Jörn; Brenner, Günter; Ekanayake, Nagitha; Faatz, Bart; Hacker, Kirsten; Honkavaara, Katja; Lazzarino, Leslie Lamberto; Lechner, Christoph; Maltezopoulos, Theophilos; Scholz, Matthias; Schreiber, Siegfried; Vogt, Mathias; Zemella, Johann; Laarmann, Tim

    2016-09-01

    Free-electron lasers (FELs) generate femtosecond XUV and X-ray pulses at peak powers in the gigawatt range. The FEL user facility FLASH at DESY (Hamburg, Germany) is driven by a superconducting linear accelerator with up to 8000 pulses per second. Since 2014, two parallel undulator beamlines, FLASH1 and FLASH2, have been in operation. In addition to the main undulator, the FLASH1 beamline is equipped with an undulator section, sFLASH, dedicated to research and development of fully coherent extreme ultraviolet photon pulses using external seed lasers. In this contribution, the first simultaneous lasing of the three FELs at 13.4 nm, 20 nm and 38.8 nm is presented. PMID:27577757

  15. Measurement of reduced corkscrew motion on the ETA-II linear induction accelerator

    International Nuclear Information System (INIS)

    The ETA-II linear induction accelerator is used to drive a microwave free-electron laser (FEL). Corkscrew motion, which previously limited performance, has been reduced by: (1) an improved pulse distribution system which reduced energy sweep, (2) improved magnetic alignment achieved with a stretched wire alignment technique (SWAT), and (3) a unique magnetic tuning algorithm. Experiments have been carried out on a 20-cell version of ETA-II operating at 1500 A and 2.7 MeV. The measured transverse beam motion is less than 0.5 mm for 40 ns of the pulse, an improvement of a factor of 2 to 3 over previous results. Details of the computerized tuning procedure, estimates of the corkscrew phase, and relevance of these results to future FEL experiments are presented

  16. Validation of head scatter factor for an Elekta synergy platform linear accelerator

    International Nuclear Information System (INIS)

    A semi-empirical method has been proposed and developed to model and compute head or collimator scatter factors for 6 and 15 MV photon beams from Elekta Synergy platform linear accelerator at the radiation oncology centre of 'Sweden-Ghana Medical Centre Limited', East Legon Hills in Accra. The proposed model was based on two dimensional Gaussian distribution, whose output was compared to measured head scatter factor data for the linear accelerator obtained during commissioning of the teletherapy machine. The two dimensions Gaussian distribution model used physical specifications and configuration of the head unit (collimator system) of the linear accelerator, which were obtained from the user manual provided by the manufacturer of the linear accelerator. The algorithm for the model was implemented using Matlab software in the Microsoft windows environment. The model was done for both square and rectangular fields, and the output compared with corresponding measured data. The comparisons for the square fields were used to establish an error term in the Gaussian distribution function. The error term was determined by plotting the difference between the output factors from MatLab and the corresponding measured data as function of one side of a square field (equivalent square field). The correlation equation of the curve obtained was chosen as the error term, which was incorporated into the Gaussian distribution function. This was repeated for two photon beam energies (6 and 15 MV). The refined Gaussian distributions were then used to determine head scatter factors for square and rectangular fields. For the rectangular fields, Sterling's proposed formula was used to find equivalent square used to obtain the equivalent square fields found in the error terms of the proposed formula was sed to find equivalent square used to obtain the equivalent square fields found in the error terms of the proposed and developed model. The output of the 2D Gaussian distribution without

  17. Absolute energy calibration of ultra-high energy cosmic telescope with a portable electron linear accelerator

    International Nuclear Information System (INIS)

    Telescope Array experiment (TA) which observes the ultra-high energy cosmic rays (UHECRs) was started from 2008 at Utah State in U.S. We will calibrate the absolute energy scale of fluorescence detector (FD) with a portable electron linear accelerator (ELS) of which typical beam intensity is 40 MeV x 109 e- per pulse. The ELS is installed at 100 m from the FD. We operated the ELS every about four months, and took data for energy calibration. The most important beam study is measurement of beam charge of each pulse. In this article, we will report about the beam charge measurement study and first results of FD absolute energy calibration with the ELS. (author)

  18. High resolution electron scattering facility at the Darmstadt linear accelerator (DALINAC) II

    International Nuclear Information System (INIS)

    Design and installation of a high resolution energy-loss electron scattering system at the Darmstadt linear accelerator are described. The apparatus consists of a beam transport system with two 700-dipole bending magnets, eleven quadrupole focussing magnets, a five quadrupole magnet set as rotating element, and a magic angle (169.70) spectrometer for analyzing the scattering electrons. For a primary momentum spread Δp/p0 = 3 X 10-3, a spectrometer acceptance solid angle Ω = 5 msr, and a 10 mg/cm2 thick Be target, the resolution was measured to be Δp/p0 = 4 X 10-4, equivalent to 25 keV for 60 MeV electrons. (Auth.)

  19. Characteristic For Electron Beam Of A Clinac 2100 Linear Accelerator Machine

    International Nuclear Information System (INIS)

    This paper describes the measurement of some dosimetric parameters for 6, 9, 12, 16 and 20 MeV electron beam of a CLINAC 2100 linear accelerator machine. The measurement were performed using Wellhofer dosimeter system at focus surface distance of 100 cm and a field size of 15 cm x 15 cm at the water phantom. The dosimetric parameter were automatically calculated from each scan. The result obtained show that the value of the depth of maximum ionization were at 1.30, 2.00, 2.66, 2.45 and 1.76 cm each for 6, 9, 12, 16 and 20 MeV nominal energy. The beam flatness varies between 0.86 to 3.68%, the beam symmetry between 0.0 to 1.55% and the penumbra between 7.4 mm to 12.4 mm. (author)

  20. Subthreshold and near-subthreshold fission physics measurements at the Oak Ridge Electron Linear Accelerator Facility

    International Nuclear Information System (INIS)

    This paper is an account of the work performed at the Oak Ridge Electron Linear Accelerator (ORELA), pertaining to the fission phenomena taking place at energies of the fissioning nucleus which are comparable to the fission barrier potential energy. In this energy region, fission cross-section measurements yield information on the physical properties of the barrier and on the nuclear states at high nuclear deformations. The ORELA facility intense pulsed neutron source and good energy resolution capabilities afford a convenient tool to carry out a program of measurements in the subthreshold and near-subthreshold regions. Extensive and precise measurements in the actinide region were performed at the ORELA facility by an international group of researchers. These measurements were unique in many respects: fission widths and areas were determined for many previously unreported resonances in the subthreshold region and a most detailed study was performed on the physical properties of the fission barrier at high nuclear deformations

  1. An Electron Bunch Compression Scheme for a Superconducting Radio Frequency Linear Accelerator Driven Light Source

    Energy Technology Data Exchange (ETDEWEB)

    C. Tennant, S.V. Benson, D. Douglas, P. Evtushenko, R.A. Legg

    2011-09-01

    We describe an electron bunch compression scheme suitable for use in a light source driven by a superconducting radio frequency (SRF) linac. The key feature is the use of a recirculating linac to perform the initial bunch compression. Phasing of the second pass beam through the linac is chosen to de-chirp the electron bunch prior to acceleration to the final energy in an SRF linac ('afterburner'). The final bunch compression is then done at maximum energy. This scheme has the potential to circumvent some of the most technically challenging aspects of current longitudinal matches; namely transporting a fully compressed, high peak current electron bunch through an extended SRF environment, the need for a RF harmonic linearizer and the need for a laser heater. Additional benefits include a substantial savings in capital and operational costs by efficiently using the available SRF gradient.

  2. Challenges in Linear Accelerator Radiotherapy for Chordomas and Chondrosarcomas of the Skull Base: Focus on Complications

    Energy Technology Data Exchange (ETDEWEB)

    Hauptman, Jason S., E-mail: jhauptman@mednet.ucla.edu [Division of Stereotactic and Functional Neurosurgery, Department of Neurosurgery, University of California, Los Angeles, David Geffen School of Medicine, Los Angeles, CA (United States); Barkhoudarian, Garni; Safaee, Michael; Gorgulho, Alessandra [Division of Stereotactic and Functional Neurosurgery, Department of Neurosurgery, University of California, Los Angeles, David Geffen School of Medicine, Los Angeles, CA (United States); Tenn, Steven; Agazaryan, Nzhde; Selch, Michael [Department of Radiation Oncology, University of California, Los Angeles, David Geffen School of Medicine, Los Angeles, CA (United States); De Salles, Antonio A.F. [Division of Stereotactic and Functional Neurosurgery, Department of Neurosurgery, University of California, Los Angeles, David Geffen School of Medicine, Los Angeles, CA (United States); Department of Radiation Oncology, University of California, Los Angeles, David Geffen School of Medicine, Los Angeles, CA (United States)

    2012-06-01

    Purpose: Intracranial chordomas and chondrosarcomas are histologically low-grade, locally invasive tumors that infiltrate the skull base. Currently, consensus therapy includes surgical resection and adjuvant radiotherapy. Radiation delivery is typically limited by the proximity of these tumors to critical skull base structures. Methods: This is a retrospective review of 13 cases of chordomas and 2 cases of chondroid chondrosarcomas of the skull based treated with linear accelerator stereotactic radiotherapy (SRT, n = 10) or stereotactic radiosurgery (SRS, n = 5). The average time to the most recent follow-up visit was 4.5 years. The tumor characteristics, treatment details, and outcomes were recorded. Each radiation plan was reviewed, and the dosage received by the brainstem, optic apparatus, and pituitary was calculated. Results: Of the 10 patients treated with SRT, 6 were found to have unchanged or decreased tumor size as determined from radiographic follow-up. Of the 5 patients treated with SRS, 3 were found to have stable or unchanged tumors at follow-up. The complications included 1 SRT patient who developed endocrinopathy, 2 patients (1 treated with SRS and the other with SRT), who developed cranial neuropathy, and 1 SRS patient who developed visual deficits. Additionally, 1 patient who received both SRS and SRT within 2 years for recurrence experienced transient medial temporal lobe radiation changes that resolved. Conclusions: Where proton beam therapy is unavailable, linear accelerator-based SRT or radiosurgery remains a safe option for adjuvant therapy of chordomas and chondrosarcomas of the skull base. The exposure of the optic apparatus, pituitary stalk, and brainstem must be considered during planning to minimize complications. If the optic apparatus is included in the 80% isodose line, it might be best to fractionate therapy. Exposure of the pituitary stalk should be kept to <30 Gy to minimize endocrine dysfunction. Brainstem exposure should be

  3. Challenges in Linear Accelerator Radiotherapy for Chordomas and Chondrosarcomas of the Skull Base: Focus on Complications

    International Nuclear Information System (INIS)

    Purpose: Intracranial chordomas and chondrosarcomas are histologically low-grade, locally invasive tumors that infiltrate the skull base. Currently, consensus therapy includes surgical resection and adjuvant radiotherapy. Radiation delivery is typically limited by the proximity of these tumors to critical skull base structures. Methods: This is a retrospective review of 13 cases of chordomas and 2 cases of chondroid chondrosarcomas of the skull based treated with linear accelerator stereotactic radiotherapy (SRT, n = 10) or stereotactic radiosurgery (SRS, n = 5). The average time to the most recent follow-up visit was 4.5 years. The tumor characteristics, treatment details, and outcomes were recorded. Each radiation plan was reviewed, and the dosage received by the brainstem, optic apparatus, and pituitary was calculated. Results: Of the 10 patients treated with SRT, 6 were found to have unchanged or decreased tumor size as determined from radiographic follow-up. Of the 5 patients treated with SRS, 3 were found to have stable or unchanged tumors at follow-up. The complications included 1 SRT patient who developed endocrinopathy, 2 patients (1 treated with SRS and the other with SRT), who developed cranial neuropathy, and 1 SRS patient who developed visual deficits. Additionally, 1 patient who received both SRS and SRT within 2 years for recurrence experienced transient medial temporal lobe radiation changes that resolved. Conclusions: Where proton beam therapy is unavailable, linear accelerator-based SRT or radiosurgery remains a safe option for adjuvant therapy of chordomas and chondrosarcomas of the skull base. The exposure of the optic apparatus, pituitary stalk, and brainstem must be considered during planning to minimize complications. If the optic apparatus is included in the 80% isodose line, it might be best to fractionate therapy. Exposure of the pituitary stalk should be kept to <30 Gy to minimize endocrine dysfunction. Brainstem exposure should be

  4. Effect of the new carbon fiber board of Elekta Precise linear accelerator on the radiation dose

    International Nuclear Information System (INIS)

    Objective: To investigate the dosimetric influence of pure carbon fiber treatment tabletop of Elekta Precise new linear accelerator in radiotherapy. Methods: Surface-axis distance (SAD) technology was employed for the measurement. Two groups of fields were set and both of them were SAD opposed portals (one of them went through the tabletop,while the other did not). A PTW electrometer and a 0.6 cm3 Farmer ionization chamber were utilized for comparison measurement. Then dose attenuation of the main table board, extended body board, the extended board for head, neck and shoulders, and the joints of these boards were calculated. Results: Under the energy of 6 MV,the dose attenuations of the following locations were: 1.4% - 7.2% at the main treatment table board; 2.8% - 38.7%, 1.4% -30.1%, 1.5% -20.8% and 1.4% - 11.2%, respectively at distances of 1, 4, 7 and 8 cm from the joint of the main table board; 0.5% - 5.0% at the extended body board; 4.7% - 15.4% at distance of 1 cm from the joint of the extended body board; 0.5% -3.3% at the neck position of the extended board for head, neck and shoulders; 5.3% - 16.7% at the shoulder positions; and 6.8% -30.4% at the joint between the extended boards and the main table board. Conclusions: The dose attenuations of the new linear accelerator pure carbon fiber treatment tabletop vary at different locations. Considerable higher attenuations are observed at the table board joints than other locations. (authors)

  5. Neutron research and facility development at the Oak Ridge Electron Linear Accelerator 1970 to 1995

    International Nuclear Information System (INIS)

    This report reviews the accomplishments of the first decade of operation of the Oak Ridge Electron Linear Accelerator (ORELA) and discusses the plans for the facility in the coming decade. Motivations for scientific and applied research during the next decade are included. In addition, ORELA is compared with competing facilities, and prospects for ORELA's improvement and even replacement are reported. Development efforts for the next few years are outlined that are consistent with the anticipated research goals. Recommendations for hardware development include improving the electron injection system to give much larger short-pulse currents on a reliable basis, constructing an Electron Beam Injector Laboratory to help make this improvement possible, continuing a study of possibly replacing the electron accelerator with a proton machine, and replacing or upgrading the facility's data-acquistion and immediate-analysis computer systems. Increased operating time and more involvement of nuclear theorists are recommended, and an effective staff size for optimum use of this unique facility is discussed. A bibliography of all ORELA-related publications is included

  6. The development of seismic guidelines for the Stanford Linear Accelerator Center

    International Nuclear Information System (INIS)

    This paper describes the development of Seismic Guidelines for the Stanford Linear Accelerator Center (SLAC). Although structures have always been built conservatively, SLAC management decided to review and update their seismic guidelines. SLAC is about mid-way between the epicenters of the 8.3 Richter magnitude 1906 San Francisco and the 7.2 Loma Prieta Earthquakes. The west end of the two mile long electron/positron particle accelerator lies a half mile from the large San Andreas Fault. Suggestions for seismic planning processes were solicited from local computer manufacturing firms, universities, and federal laboratories. A Committee of the various stakeholders in SLAC's seismic planning retained an internationally known Seismic Planning Consultant and reviewed relevant standards and drafted Guidelines. A panel of seismic experts was convened to help define the hazard, site response spectra, probabilistic analysis of shaking, and near field effects. The Facility's structures were assigned to seismic classes of importance, and an initial assessment of a sample of a dozen buildings conducted. This assessment resulted in emergency repairs to one structure, and provided a open-quotes reality basisclose quotes for establishing the final Guidelines and Administrative Procedures, and a program to evaluate remaining buildings, shielding walls, tunnels, and other special structures

  7. Characterestics of pico-second single bunch at the S-band linear accelerator

    International Nuclear Information System (INIS)

    Measurement of the bunch structure of a pico-second single bunch was performed using a femto-second streak camera at the S-band linear accelerator of the University of Tokyo. The aim of this research is to investigate the feasibility of the generation of a femto-second single bunch at the S-band linac. The details of the bunch structure and energy spectrum of an original single bunch were precisely investigated in several operation modes where the RF phases in accelerating tubes and a prebuncher were varied. The femto-second streak camera was utilized to measure the bunch structure by one shot via Cherenkov radiation emitted by the electrons in the bunch. Next, an experiment for magnetic pulse compression of the original single bunch was carried out. Pulse shapes of the compressed bunchs for different energy modulation were also obtained by measuring Cherenkov radiation by one shot using the femto-second streak camera. Prior to the experiment, numerical tracking analysis to determine operating parameters for the magnetic pulse compression was also done. Measured pulse widths were compared with calculated ones. Finally, a 2 ps (full width at half maximum; FWHM) single bunch with an electric charge of 0.3 nC could be generated by the magnetic pulse compression. ((orig.))

  8. The development of seismic guidelines for the Stanford Linear Accelerator Center

    Energy Technology Data Exchange (ETDEWEB)

    Huggins, R.

    1996-08-01

    This paper describes the development of Seismic Guidelines for the Stanford Linear Accelerator Center (SLAC). Although structures have always been built conservatively, SLAC management decided to review and update their seismic guidelines. SLAC is about mid-way between the epicenters of the 8.3 Richter magnitude 1906 San Francisco and the 7.2 Loma Prieta Earthquakes. The west end of the two mile long electron/positron particle accelerator lies a half mile from the large San Andreas Fault. Suggestions for seismic planning processes were solicited from local computer manufacturing firms, universities, and federal laboratories. A Committee of the various stakeholders in SLAC`s seismic planning retained an internationally known Seismic Planning Consultant and reviewed relevant standards and drafted Guidelines. A panel of seismic experts was convened to help define the hazard, site response spectra, probabilistic analysis of shaking, and near field effects. The Facility`s structures were assigned to seismic classes of importance, and an initial assessment of a sample of a dozen buildings conducted. This assessment resulted in emergency repairs to one structure, and provided a {open_quotes}reality basis{close_quotes} for establishing the final Guidelines and Administrative Procedures, and a program to evaluate remaining buildings, shielding walls, tunnels, and other special structures.

  9. Formation of a sequence chains of nanosecond ion bunches for injection in a linear accelerator

    International Nuclear Information System (INIS)

    Currently there are generators of intense ion beams of nanosecond duration. For the purpose of the injection such ions into a linear accelerator the formation of a sequence ∼ 102 ion bunches of a duration of 20 ns, a current of ∼ 100 mA total current pulse duration of about 1 .s is considered in this work. In this case, bunches of highly charged ions (HCI) of aluminum are generated by field emission by applying a voltage of 400 kV, a duration of 50 ns at a block of aluminum emitters, spaced along the axis of the injector. The injector consists of a sequence co-axial emitters, a grounded accelerating grid and a retarding-and-turning grid. Trough the retarding-and-turning grid a current is passed from the current pulse generator, which creates an azimuthal magnetic field directing HTI along the axis. The analytical calculations that determine the parameters and confirming the possibility of the technical realization of such a device are shown.

  10. Linear accelerator and MLC Monte Carlo model in EGSnrc/BEAMnrc system

    International Nuclear Information System (INIS)

    In radiotherapy (RT) the Monte Carlo (MC) method is used especially as a golden standard for comparison with measured data, modelling of a detector response or a treatment planning system (TPS) calculation. In last years, using of an IMRT technique has been rapidly increasing in developed countries and also in Czech Republic. Benefit of IMRT is strongly dependent on a precise treatment planning and accurate target volume dose delivery. Precise dose delivering is interwoven with IGRT and for dose distribution verification the phantom measurement is usually performed. However, this way of verification may not discover possible dose distribution discrepancy between TPS and a patient. MC modelling is suitable especially for this situation. Recently increased interest in this field can be noticed in foreign authors works. Although IMRT technique is commonly used in our country this topic is not investigated. The MC simulation for IMRT is based on a verified linear accelerator treatment head model. In our case the model of Clinac 2100 C/D (Varian Medical System) is created. EGSnrc/BEAMnrc code is used for MC modelling. This system is adjusted especially for RT simulation. The model can be divided into several subsections. It is necessary to know precise accelerator treatment head geometrical parameters (from a producer) and convert them to EGSnrc/BEAMnrc. (authors)

  11. On the preservation of single- and multi-bunch emittance in linear accelerators

    International Nuclear Information System (INIS)

    This document is concentrated on the investigation of the dynamics of a particle beam in a linear accelerator. We numerically simulate a number of effects and evaluate the severity of their impact on the beam. Furthermore, we examine the applicability of several correction techniques aiming at the suppression or correction of the effects diluting the beam emittance. First, there is the issue of single-bunch dynamics : we see that wake field effects and dispersive errors can cause a significant emittance growth. Secondly, long range dipole wakes and dispersive effects arising from the energy spread between different bunches will cause relative offsets between the individual bunches and likewise result in emittance growth. Finally, we observe interactions between the single-bunch and multi-bunch dynamics in a bunch train, which further aggravate these effects. The corrective measures against emittance growth are first tested with respect to individual effects relating to issues of single- or multi-bunch dynamics. Later, these different correction techniques are joined to one machine tuning procedure that will be applied in order to achieve good emittance preservation for operation of the accelerator with a full beam consisting of the full number of bunches. The performance of this procedure is tested in simulations of the combined single- and multi-bunch dynamics. Finally, tolerances on the machine alignment as well as machine and beam parameters are established. (orig.)

  12. Electron beam sub-harmonics chopping system for linear accelerator injector

    International Nuclear Information System (INIS)

    The need of a 100 % duty cycle electron accelerator for use in nuclear physics, has led in 1981 the CEN Saclay Linear Accelerator Group, to study a machine using the existing linac associated with a pulse stretcher ring. The production of electron bunches at the ring RF frequency (600 MHz) requires the design of a new injector including a chopping beam System with a deflecting electromagnetic cavity and a collimator. A comparison between four transverse magnetic modes, led to choose a TM110 parallelepiped chopper. The construction of a prototype and of a vacuum-tight cavity followed by microwave measurements has permitted to solve several mechanical problems and to specify the cavity electrical properties. In a first step, the beam line, including - focusing, offset deflection coils, chopping with a rectangular collimator - has been studied, for zero intensity beam current, on the basis of a matrix model. An experimental 40 keV beam line, has been assembled to measure the bunch length. The method was based on a spectral analysis of the signal delivered by a large band, 50 ohms adapted beam collector. The bunch shape in the time domain was reconstructed by inverse Fourier transform. The beam dynamics has been studied with a 3D space charge model which has been introduced into the PARMELA tracking code. Simulations showed that a 150 keV, 2 A beam could be chopped with the same deflecting lay-out. (author)

  13. Evaluation of a risk communication approach for maintenance staff working with induced radioactivity in medical linear accelerators

    International Nuclear Information System (INIS)

    In order to promote consensus building on decommissioning operation rules for medical linear accelerators in Japan, we carried out a risk communication (RC) approach mainly providing knowledge for maintenance staff regarding induced radioactivity. In February 2012, we created a booklet (26 pages) to present an overview of the amended law, the mechanism and the distribution of induced radioactivity showing the actual radiation dose rate around a linear accelerator and actual exposure doses to staff. In addition, we co-sponsored a seminar for workers in this field organized by the Japan Medical Imaging and Radiological Systems Industries Association to explain the contents of this booklet, and answer questions regarding induced radioactivity of linear accelerators as an RC program. As a result, the understanding of staff regarding the regulations on maximum X-ray energy on linear accelerators (P<0.05), and the outline of clearance systems (P<0.01), were facilitated by RC. In addition, we found that about 70% of maintenance staff considered that the cooling time for decommissioning operation depended on the situation. Our RC approach suggests that consensus building should be used to make rules on decommissioning operations for linear medical accelerators. (author)

  14. Dose non-linearity of the dosimetry system and possible monitor unit errors on medical linear accelerators used in conventional and intensity-modulated radiation therapy

    Directory of Open Access Journals (Sweden)

    Muhammad Wazir

    2012-01-01

    Full Text Available The purpose of this work is to study dose non-linearity in medical linear accelerators used in conventional radiotherapy and intensity-modulated radiation therapy. Open fields, as well as the enhanced dynamic wedge ones, were used to collect data for 6 MV and 15 MV photon beams obtained from the VARIAN linear accelerator. Beam stability was checked and confirmed for different dose rates, energies, and application of enhanced dynamic wedge by calculating the charge per monitor unit. Monitor unit error was calculated by the two-exposure method for open and enhanced dynamic wedge beams of 6 MV and 15 MV photons. A significant monitor unit error with maximum values of ±2.05931 monitor unit and ±2.44787 monitor unit for open and enhanced dynamic wedge beams, respectively, both energy and dose rate dependent, was observed both in the open photon beam and enhanced dynamic wedge fields. However, it exhibited certain irregular patterns at enhanced dynamic wedge angles. Dose monitor unit error exists only because of the overshoot phenomena and electronic delay in dose coincident and integrated circuits with a dependency on the dose rate and photon energy. Monitor unit errors are independent of the application of enhanced dynamic wedge. The existence of monitor unit error demands that the dose non-linearity of the linear accelerator dosimetry system be periodically tested, so as to avoid significant dosimetric errors.

  15. New Empirical Formula for Neutron Dose Level at the Maze of Medical Linear Accelerator Facilities

    International Nuclear Information System (INIS)

    dose rates at the doorways were made for 697 different treatment room configurations which were generated by step changing the geometry parameters within the range observed in the running treatment rooms. Finally, the empirical formula was yielded by a multiple regression fit to the neutron dose equivalents at the doorway for the above 697 configurations: H = 92.43 (do/dm)0.518 (da)-0.794 (So)1.40 (dc)-3.46 where H is the neutron dose equivalent at the maze entrance in mSv per Gy of photon dose at the isocenter and do width of the maze entrance, dm maze wall thickness, da distance from the isocenter to the maze wall, So cross-sectional area of the inner maze entrance, dc depth of the maze less 120 cm. All lengths are in centimeters. The goodness of the empirical formula developed in this work was evaluated for 7 operating treatment facilities with the different makers of accelerators. The formula of this work yielded neutron dose equivalents at the doorway significantly lower than the Kersey method but maintained conservatism over the doses computed by MCNPX and the measured values with neutron survey meters. It was concluded that this formula is suitable for use in the design of maze for 15 MV medical linear accelerators with one bend maze

  16. Temporal characterization of ultrashort linearly chirped electron bunches generated from a laser wakefield accelerator

    Science.gov (United States)

    Zhang, C. J.; Hua, J. F.; Wan, Y.; Guo, B.; Pai, C.-H.; Wu, Y. P.; Li, F.; Chu, H.-H.; Gu, Y. Q.; Mori, W. B.; Joshi, C.; Wang, J.; Lu, W.

    2016-06-01

    A new method for diagnosing the temporal characteristics of ultrashort electron bunches with linear energy chirp generated from a laser wakefield accelerator is described. When the ionization-injected bunch interacts with the back of the drive laser, it is deflected and stretched along the direction of the electric field of the laser. Upon exiting the plasma, if the bunch goes through a narrow slit in front of the dipole magnet that disperses the electrons in the plane of the laser polarization, it can form a series of bunchlets that have different energies but are separated by half a laser wavelength. Since only the electrons that are undeflected by the laser go through the slit, the energy spectrum of the bunch is modulated. By analyzing the modulated energy spectrum, the shots where the bunch has a linear energy chirp can be recognized. Consequently, the energy chirp and beam current profile of those bunches can be reconstructed. This method is demonstrated through particle-in-cell simulations and experiment.

  17. Definition of a reference metrology network for the positioning of a large linear accelerator

    International Nuclear Information System (INIS)

    This thesis is a study of the Compact Linear Collider (CLIC) alignment system, a project of linear accelerator of about 30 km long of the European Organization for Nuclear Research (CERN). The pre-alignment tolerance on the transverse positions of the components of the CLIC linacs is typically ten microns over distances of 200 m. This research is a consequence of 10 years work, where several sets of special sensors dedicated to metrology have been adapted for the CLIC project. Most of these sensors deliver measurements linked to geometric references sensitive to gravity fluctuation. An important part of this work is therefore dedicated to study the gravity disruptions as a high level of accuracy is required. The parameters to take into account in the use of the hydrostatic leveling have thus been highlighted. A proposal of configuration of the system alignment based on a selection of sensors has also been given in this research. Computer models of different possible configurations have been presented. As the existing computing software was inappropriate, a new object oriented software package has been developed, to ensure future upgrades. An optimized configuration of the network has been defined from a set of simulations. Finally, due to problems in the use of hydrostatic leveling systems, a solution based on the use of a long laser beam as an alternative solution is discussed. (author)

  18. Transverse beam dynamics in non-linear Fixed Field Alternating Gradient accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Haj, Tahar M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-03-02

    In this paper, we present some aspects of the transverse beam dynamics in Fixed Field Ring Accelerators (FFRA): we start from the basic principles in order to derive the linearized transverse particle equations of motion for FFRA, essentially FFAGs and cyclotrons are considered here. This is a simple extension of a previous work valid for linear lattices that we generalized by including the bending terms to ensure its correctness for FFAG lattice. The space charge term (contribution of the internal coulombian forces of the beam) is contained as well, although it is not discussed here. The emphasis is on the scaling FFAG type: a collaboration work is undertaken in view of better understanding the properties of the 150 MeV scaling FFAG at KURRI in Japan, and progress towards high intensity operation. Some results of the benchmarking work between different codes are presented. Analysis of certain type of field imperfections revealed some interesting features about this machine that explain some of the experimental results and generalize the concept of a scaling FFAG to a non-scaling one for which the tune variations obey a well-defined law.

  19. Physical properties of a linear accelerator-based stereotactic installed at national cancer institute

    International Nuclear Information System (INIS)

    The purpose of this paper is to present the dosimetry and mechanical accuracy of the first dedicated Siemens PRIMUS M6/6ST linear accelerator-based Stereotactic installed in National Cancer Institute for stereotactic radiosurgery and radiotherapy (SRS/SRT). The data were obtained during the installation, acceptance test procedure, and commissioning of the unit. The Primus M6/6ST has a single 6-MV beam with the same beam characteristics as that of the mother unit, the Siemens. The dosimetric data were taken using pin point ion chamber. The cone sizes vary from 12.5 to 40.0 mm diameter. The mechanical stability of the entire system was verified. The variations in isocenter position with table, gantry, and collimator rotation were found to be < 0.5 mm with a compounded accuracy of < or = 1.0 mm. The beam profiles of all cones in the x and y directions were within +/- 0.5 mm and match with the physical size of the cone. The basic dosimetry parameters such as tissue maximum ratio (TMR), off-axis ratio (OAR) and cone factor needed for patient treatment were evaluated. The mechanical and dosimetric characteristics including dose linearity of this unit are presented and found to be suitable for SRS/SRT. The difficulty in absolute dose measurement for small cone is discussed

  20. A Combined Shielding Design for a Neutron Generator and a Linear Accelerator at Soreq NRC

    International Nuclear Information System (INIS)

    A new radiography facility is designed at Soreq NRC. The facility will hold a neutron generator that produces 1.73·109 n/s with an energy of 14 MeV and a linear accelerator that accelerates electrons to an energy of 9 MeV. The two radiation sources will be installed in 2 separate laboratories that will be built in an existing building. Each laboratory will have its own machine and control room. The dose rates around the sources were calculated using the FLUKA Monte Carlo code(1,2). The annual doses were calculated in several regions around the generator and the accelerator laboratories in accordance with the occupancy in each area. The calculated annual doses were compared with the dose limits specified in the Safety at Work Regulations(3) and the IAEC Standard for Protection against Ionizing Radiation. The shielding was designed to comply with the following dose constraints: 0.3 mSv/y for members of the public and 2 mSv/y for radiation workers. Each radiation source is planned to produce radiation for a maximum of 500 hours per year. The dose rate in the direct beam of the accelerator is 30 Gy/min at 1 m from the source and it will be surrounded by a collimator with an opening of 30N-tilde horizontally and 2 mm vertically, 3 m from the radiation source. The leakage radiation dose will not be greater than 1.5 mGy/min (0.005% of the direct beam, according to the manufacturer). The leakage radiation will be produced isotropically. The neutron generator will be surrounded by a shielding made of a 10 cm iron cylinder (density 7.87 g/cm3), surrounded by 50 cm of borated polyethylene (atomic percent: H (13.8%), C (82.2%), B (4%), density: 0.92 g/cm3) and 5 cm of lead (density 11.35 g/cm3). The neutron generator shielding was not designed or required in the present shielding design but was considered in the shielding calculations

  1. A 50-MeV mm-wave electron linear accelerator system for production of tunable short wavelength synchrotron radiation

    International Nuclear Information System (INIS)

    The Advanced Photon Source (APS) at Argonne in collaboration with the University of Illinois at Chicago and the University of Wisconsin at Madison is developing a new millimeter wavelength, 50-MeV electron linear accelerator system for production of coherent tunable wavelength synchrotron radiation. Modern micromachining techniques based on deep etch x-ray lithography, LIGA (Lithografie, Galvanoformung, Abformung), capable of producing high-aspect ratio structures are being considered for the fabrication of the accelerating components

  2. Whole body electron therapy using the Philips SL75/10 linear accelerator

    International Nuclear Information System (INIS)

    Electrons produced by accelerators are always accompanied by Bremsstrahlung radiation generated by electron interactions with the accelerator exit window, monitor ionization chamber, collimator, etc. The ratio of the Bremsstrahlung x-rays to electrons depends on the design of the accelerator, beam energy and adjustment, and the treatment set-up. For the electron mode of the Philips SL75/10 linac, x-rays normally constitute 1-2% of the beam at a distance of 1 meter. While this is acceptable for conventional treatments when electrons are used for whole-body irradiation, the x-ray contamination can become excessive because of the degrading effects of the large treatment distances or scattering foils required to produce large fields. A whole body electron treatment method for the SL75/10 linac, with emphasis on the means employed to minimize the x-ray dose to the patient, is described. Measurements of the properties of the electro; beams and their x-ray components were made with the aid of a thin parallel plate ionization chamber, thermoluminescent dosimeters and films in various phantoms. From analysis of the results of the measurements a practical method for treating patients was developed. The method is based on multiple adjacent beams of 4 Mev electrons applied while the patient lies on the treatment couch at a distance of 150cm from the source. The method satisfies the clinical requirements with regard to the depth and uniformity of electron dose and the level of x-ray contamination. It is not necessary to modify the linac or to use any special devices when giving the treatment. (author)

  3. Advances in medical electron linear accelerator technologies and the development of a next generation robotic radiation therapy system

    International Nuclear Information System (INIS)

    Radiation therapy for cancer began in the early 20th century with X-ray tubes delivering a few hundred keV. Through the 1930's to 1940's, 2 MV Van de Graaff accelerators and Betatrons of 20 to 45 MeV were used for cancer treatment. In the mid 1950's, radiation therapy combined 4 to 8 MeV linear accelerators with several high power microwave magnetrons and klystrons working in the megawatt range that have been developed for radar applications during the second world war. Since then, the linear accelerator became the most commonly used technology for radiation therapy and nowadays, more than 8000 linear accelerators are contributing to the treatment of cancer worldwide. We present the development of a real-time 3D robotic radiation therapy system combined with a compact X-band linear accelerator for the early detection of deep seated, small tumors. The system utilizes multiple narrow high energy X-ray beams focused on the target tumor. Real-time positioning is achieved by non-invasive methods based on correlation models for tumor motion and respiratory signals. Emphasis is placed on the tumor motion which is used to control a robotic head with six degrees of freedom to fix the tumor in a certain spatial position. (author)

  4. SU-E-T-190: First Integration of Steriotactic Radiotherapy Planning System Iplan with Elekta Linear Accelerator

    International Nuclear Information System (INIS)

    Purpose: For the first time in the world, BrainLAB has integrated its iPlan treatment planning system for clinical use with Elekta linear accelerator (Axesse with a Beam Modulator). The purpose of this study was to compare the calculated and measured doses with different chambers to establish the calculation accuracy of iPlan system. Methods: The iPlan has both Pencil beam (PB) and Monte Carlo (MC) calculation algorithms. Beam data include depth doses, profiles and output measurements for different field sizes. Collected data was verified by vendor and beam modelling was done. Further QA tests were carried out in our clinic. Dose calculation accuracy verified point, volumetric dose measurement using ion chambers of different volumes (0.01cc and 0.125cc). Planner dose verification was done using diode array. Plans were generated in iPlan and irradiated in Elekta Axesse linear accelerator. Results: Dose calculation accuracies verified using ion chamber for 6 and 10 MV beam were 3.5+/-0.33(PB), 1.7%+/-0.7(MC) and 3.9%+/-0.6(PB), 3.4%+/-0.6(MC) respectively. Using a pin point chamber, dose calculation accuracy for 6MV and 10MV was 3.8%+/-0.06(PB), 1.21%+/-0.2(MC) and 4.2%+/-0.6(PB), 3.1%+/-0.7(MC) respectively. The calculated planar dose distribution for 10.4×10.4 cm2 was verified using a diode array and the gamma analysis for 2%-2mm criteria yielded pass rates of 88 %(PB) and 98.8%(MC) respectively. 3mm-3% yields 100% passing for both MC and PB algorithm. Conclusion: Dose calculation accuracy was found to be within acceptable limits for MC for 6MV beam. PB for both beams and MC for 10 MV beam were found to be outside acceptable limits. The output measurements were done twice for conformation. The lower gamma matching was attributed to meager number of measured profiles (only two profiles for PB) and coarse measurement resolution for diagonal profile measurement (5mm). Based on these measurements we concluded that 6 MV MC algorithm is suitable for patient treatment

  5. Modification of the method of the perturbation theory in application to the theory of tolerances for ion linear accelerators

    International Nuclear Information System (INIS)

    A method for calculation of tolerances for linear ion accelerators by means of an original modification of perturbation theory is suggested. The equation of motion is converted so that the regular motion is separated from perturbated trajectory without the change of perturbation function. Errors of the channel are simulated in the form of thin lenses. Regular solution is determined in approximation of smooth envelopes. Simple recurrent ratio for mean square radius of the beam is obtained. The method can be useful for strong-focusing linear accelerators of any type

  6. Status report of the study on the free electron laser for the 3GHz HF linear accelerator: CLIO

    International Nuclear Information System (INIS)

    The main steps of project CLIO (Collaboration for an Infrared Laser at Orsay, France) are reported. The aim of the project is the construction of a free electron laser system, in the infrared range, for use in linear accelerators. The design and concepts of a free electron laser system are described. The linear accelerator characteristics, and those of each of the system's main components are presented. The laboratory's infrastructure, the first experiments feasibility and the research programs, which will probably make use of CLIO, are discussed

  7. Electron beam dynamics in the long-pulse, high-current DARHT-II linear induction accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Carl A [Los Alamos National Laboratory; Abeyta, Epifanio O [Los Alamos National Laboratory; Aragon, Paul [Los Alamos National Laboratory; Archuleta, Rita [Los Alamos National Laboratory; Cook, Gerald [Los Alamos National Laboratory; Dalmas, Dale [Los Alamos National Laboratory; Esquibel, Kevin [Los Alamos National Laboratory; Gallegos, Robert A [Los Alamos National Laboratory; Garnett, Robert [Los Alamos National Laboratory; Harrison, James F [Los Alamos National Laboratory; Johnson, Jeffrey B [Los Alamos National Laboratory; Jacquez, Edward B [Los Alamos National Laboratory; Mccuistian, Brian T [Los Alamos National Laboratory; Montoya, Nicholas A [Los Alamos National Laboratory; Nath, Subrato [Los Alamos National Laboratory; Nielsen, Kurt [Los Alamos National Laboratory; Oro, David [Los Alamos National Laboratory; Prichard, Benjamin [Los Alamos National Laboratory; Rowton, Lawrence [Los Alamos National Laboratory; Sanchez, Manolito [Los Alamos National Laboratory; Scarpetti, Raymond [Los Alamos National Laboratory; Schauer, Martin M [Los Alamos National Laboratory; Seitz, Gerald [Los Alamos National Laboratory; Schulze, Martin [Los Alamos National Laboratory; Bender, Howard A [Los Alamos National Laboratory; Broste, William B [Los Alamos National Laboratory; Carlson, Carl A [Los Alamos National Laboratory; Frayer, Daniel K [Los Alamos National Laboratory; Johnson, Douglas E [Los Alamos National Laboratory; Tom, C Y [Los Alamos National Laboratory; Williams, John [Los Alamos National Laboratory; Hughes, Thomas [Los Alamos National Laboratory; Anaya, Richard [LLNL; Caporaso, George [LLNL; Chambers, Frank [LLNL; Chen, Yu - Jiuan [LLNL; Falabella, Steve [LLNL; Guethlein, Gary [LLNL; Raymond, Brett [LLNL; Richardson, Roger [LLNL; Trainham, C [NSTEC/STL; Watson, Jim [LLNL; Weir, John [LLNL; Genoni, Thomas [VOSS; Toma, Carsten [VOSS

    2009-01-01

    The DARHT-II linear induction accelerator (LIA) now accelerates 2-kA electron beams to more than 17 MeV. This LIA is unique in that the accelerated current pulse width is greater than 2 microseconds. This pulse has a flat-top region where the final electron kinetic energy varies by less than 1% for more than 1.5 microseconds. The long risetime of the 6-cell injector current pulse is 0.5 {micro}s, which can be scraped off in a beam-head cleanup zone before entering the 68-cell main accelerator. We discuss our experience with tuning this novel accelerator; and present data for the resulting beam transport and dynamics. We also present beam stability data, and relate these to previous stability experiments at lower current and energy.

  8. Electron beam dynamics in the long-pulse, high-current DARHT-II linear induction accelerator

    International Nuclear Information System (INIS)

    The DARHT-II linear induction accelerator (LIA) now accelerates 2-kA electron beams to more than 17 MeV. This LIA is unique in that the accelerated current pulse width is greater than 2 microseconds. This pulse has a flat-top region where the final electron kinetic energy varies by less than 1% for more than 1.5 microseconds. The long risetime of the 6-cell injector current pulse is 0.5 (micro)s, which can be scraped off in a beam-head cleanup zone before entering the 68-cell main accelerator. We discuss our experience with tuning this novel accelerator; and present data for the resulting beam transport and dynamics. We also present beam stability data, and relate these to previous stability experiments at lower current and energy.

  9. Linear and Circular Plasmid Content in Borrelia burgdorferi Clinical Isolates

    OpenAIRE

    Iyer, Radha; Kalu, Ogori; Purser, Joye; Norris, Steven; Stevenson, Brian; Schwartz, Ira

    2003-01-01

    The genome of Borrelia burgdorferi, the etiologic agent of Lyme disease, is composed of a linear chromosome and more than 20 linear and circular plasmids. Typically, plasmid content analysis has been carried out by pulsed-field gel electrophoresis and confirmed by Southern hybridization. However, multiple plasmids of virtually identical sizes (e.g., lp28 and cp32) complicate the interpretation of such data. The present study was undertaken to investigate the complete plasmid complements of B....

  10. Development of a four cavity second-harmonic gyroklystron as driver for a linear accelerator

    Science.gov (United States)

    Gouveia, Emmanuel Steve

    Gyroklystrons are microwave amplifiers that combine the multi-cavity configuration of a klystron with the energy extraction mechanism of the cyclotron maser instability. These devices have been studied at the University of Maryland for several years. This work is focused on the development of a 17.14 GHz four-cavity frequency-doubling gyroklystron circuit. This device was designed specifically to drive a high gradient linear accelerator recently developed by the Haimson Corporation. The gyroklystron was designed using the code MAGYKL, yielding a predicted output power of 87 MW for an input drive power of 250 W, with a velocity pitch ratio (alpha) of 1.4. The tube was later fabricated, and underwent a series of experimental tests to evaluate its performance. The highest peak power observed was 18.5 +/- 1.7 MW, corresponding to an efficiency of 7.0% and a gain of 24.0 dB. This result fell short of the theoretical design, yet it was consistent with the low value of the velocity pitch ratio (alpha = 0.85) realized in the experiments. This limitation on alpha was linked to the onset of instabilities in the input cavity. The ultimate cause of these instabilities was the thermal non-uniformity in the emitter of our electron gun, which led to a significant variation (approximately 50%) of the current density across the beam. In order to remedy this problem, we have radically redesigned the input cavity, changing both its geometry and Q factor. These measures should dramatically reduce the probability of instabilities, thus allowing us to remove the experimental limitations imposed on alpha. This new design is presented here. We also describe advanced designs of an output cavity with radial power extraction, and a compact circular to rectangular mode converter. A detailed description of the present experimental setup is given, along with an overview of the power transport system necessary to feed the accelerator with output power from the gyroklystron.

  11. Output trends, characteristics, and measurements of three megavoltage radiotherapy linear accelerators.

    Science.gov (United States)

    Hossain, Murshed

    2014-01-01

    The purpose of this study is to characterize and understand the long-term behavior of the output from megavoltage radiotherapy linear accelerators. Output trends of nine beams from three linear accelerators over a period of more than three years are reported and analyzed. Output, taken during daily warm-up, forms the basis of this study. The output is measured using devices having ion chambers. These are not calibrated by accredited dosimetry laboratory, but are baseline-compared against monthly output which is measured using calibrated ion chambers. We consider the output from the daily check devices as it is, and sometimes normalized it by the actual output measured during the monthly calibration of the linacs. The data show noisy quasi-periodic behavior. The output variation, if normalized by monthly measured "real' output, is bounded between ± 3%. Beams of different energies from the same linac are correlated with a correlation coefficient as high as 0.97, for one particular linac, and as low as 0.44 for another. These maximum and minimum correlations drop to 0.78 and 0.25 when daily output is normalized by the monthly measurements. These results suggest that the origin of these correlations is both the linacs and the daily output check devices. Beams from different linacs, independent of their energies, have lower correlation coefficient, with a maximum of about 0.50 and a minimum of almost zero. The maximum correlation drops to almost zero if the output is normalized by the monthly measured output. Some scatter plots of pairs of beam output from the same linac show band-like structures. These structures are blurred when the output is normalized by the monthly calibrated output. Fourier decomposition of the quasi-periodic output is consistent with a 1/f power law. The output variation appears to come from a distorted normal distribution with a mean of slightly greater than unity. The quasi-periodic behavior is manifested in the seasonally averaged output

  12. Studies and measurements of linear coupling and nonlinearities in hadron circular accelerators

    International Nuclear Information System (INIS)

    In this thesis a beam-based method has been developed to measure the strength and the polarity of corrector magnets (skew quadrupoles and sextupoles) in circular accelerators. The algorithm is based on the harmonic analysis (via FFT) of beam position monitor (BPM) data taken turn by turn from an accelerator in operation. It has been shown that, from the differences of the spectral line amplitudes between two consecutive BPMs, both the strength and the polarity of non-linear elements placed in between can be measured. The method has been successfully tested using existing BPM data from the SPS of CERN. A second beam-based method has been studied for a fast measurement and correction of betatron coupling driven by skew quadrupole field errors and tilted focusing quadrupoles. In this thesis it has been shown how the correction for minimizing the coupling stop band C can be performed in a single machine cycle from the harmonic analysis of multi-BPM data. The method has been successfully applied to RHIC. A third theoretical achievement is a new description of the betatron motion close to the difference resonance in presence of linear coupling. New formulae describing the exchange of RMS resonances have been derived here making use of Lie algebra providing a better description of the emittance behavior. A new way to decouple the equations of motion and explicit expressions for the individual single particle invariants have been found. For the first time emittance exchange studies have been carried out in the SIS-18 of GSI. Applications of this manipulation are: emittance equilibration under consideration for future operations of the SIS-18 as booster for the SIS-100; emittance transfer during multi-turn injection to improve the efficiency and to protect the injection septum in high intensity operations, by shifting part of the horizontal emittance into the vertical plane. Multi-particle simulations with 2D PIC space-charge solver have been run to infer heuristic scaling

  13. Studies and measurements of linear coupling and nonlinearities in hadron circular accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Franchi, A.

    2006-07-01

    In this thesis a beam-based method has been developed to measure the strength and the polarity of corrector magnets (skew quadrupoles and sextupoles) in circular accelerators. The algorithm is based on the harmonic analysis (via FFT) of beam position monitor (BPM) data taken turn by turn from an accelerator in operation. It has been shown that, from the differences of the spectral line amplitudes between two consecutive BPMs, both the strength and the polarity of non-linear elements placed in between can be measured. The method has been successfully tested using existing BPM data from the SPS of CERN. A second beam-based method has been studied for a fast measurement and correction of betatron coupling driven by skew quadrupole field errors and tilted focusing quadrupoles. In this thesis it has been shown how the correction for minimizing the coupling stop band C can be performed in a single machine cycle from the harmonic analysis of multi-BPM data. The method has been successfully applied to RHIC. A third theoretical achievement is a new description of the betatron motion close to the difference resonance in presence of linear coupling. New formulae describing the exchange of RMS resonances have been derived here making use of Lie algebra providing a better description of the emittance behavior. A new way to decouple the equations of motion and explicit expressions for the individual single particle invariants have been found. For the first time emittance exchange studies have been carried out in the SIS-18 of GSI. Applications of this manipulation are: emittance equilibration under consideration for future operations of the SIS-18 as booster for the SIS-100; emittance transfer during multi-turn injection to improve the efficiency and to protect the injection septum in high intensity operations, by shifting part of the horizontal emittance into the vertical plane. Multi-particle simulations with 2D PIC space-charge solver have been run to infer heuristic scaling

  14. Accelerating Scientific Applications using High Performance Dense and Sparse Linear Algebra Kernels on GPUs

    KAUST Repository

    Abdelfattah, Ahmad

    2015-01-15

    High performance computing (HPC) platforms are evolving to more heterogeneous configurations to support the workloads of various applications. The current hardware landscape is composed of traditional multicore CPUs equipped with hardware accelerators that can handle high levels of parallelism. Graphical Processing Units (GPUs) are popular high performance hardware accelerators in modern supercomputers. GPU programming has a different model than that for CPUs, which means that many numerical kernels have to be redesigned and optimized specifically for this architecture. GPUs usually outperform multicore CPUs in some compute intensive and massively parallel applications that have regular processing patterns. However, most scientific applications rely on crucial memory-bound kernels and may witness bottlenecks due to the overhead of the memory bus latency. They can still take advantage of the GPU compute power capabilities, provided that an efficient architecture-aware design is achieved. This dissertation presents a uniform design strategy for optimizing critical memory-bound kernels on GPUs. Based on hierarchical register blocking, double buffering and latency hiding techniques, this strategy leverages the performance of a wide range of standard numerical kernels found in dense and sparse linear algebra libraries. The work presented here focuses on matrix-vector multiplication kernels (MVM) as repre- sentative and most important memory-bound operations in this context. Each kernel inherits the benefits of the proposed strategies. By exposing a proper set of tuning parameters, the strategy is flexible enough to suit different types of matrices, ranging from large dense matrices, to sparse matrices with dense block structures, while high performance is maintained. Furthermore, the tuning parameters are used to maintain the relative performance across different GPU architectures. Multi-GPU acceleration is proposed to scale the performance on several devices. The

  15. GafChromic film dosimetry for stereotactic radiosurgery with a linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Han, Seung Hee; Park, Suk Won; Oh, Do Hoon [Kangdong Sacred Heart Hospital, Seoul (Korea, Republic of); Cho, Byung Chul; Park, Hee Chul; Bae, Hoon Sik [College of Medicine, Hallym Univ., Seoul (Korea, Republic of)

    2003-06-01

    The purpose of tall study was to evaluate whether a GafChromic film applied to stereotactic radiosurgery with a linear accelerator could provide information on the value for acceptance testing and quality control on the absolute dose and relative dose measurements and/or calculation of treatment planning system. A spherical acrylic phantom, simulating a patient's head, was constructed from three points. The absolute and relative dose distributions could be measured by inserting a GafChromic film into the phantom. We tested the use of a calibrated GafChromic film (MD-55-2, Nuclear Associate, USA) for measuring the optical density. These measurements were achieved by irradiating the films with a dose of 0-112 Gy employing 6 MV photon. To verify the accuracy of the prescribed dose delivery to a target isocenter using a five arc beams (irradiated in 3 Gy per one beam) setup, calculated by the linapel planning system the absolute dose and relative dose distribution using a GafChromic film were measured. All the irradiated films were digitized with a Lumiscan 75 laser digitizer and processed with the RIT113 film dosimetry system. We verified the linearity of the Optical Density of a MD-55--2 GafChromic film, and measured the depth dose profile of the beam. The absolute dose delivered to the target was close to the prescribed dose of Linapel within an accuracy for the GafChromic film dosimetry (of{+-}3%), with a measurement uncertainty of {+-}1 mm for the 50-90% isodose lines. Our results have shown that the absolute dose and relative dose distribution curves obtained from a GafChromic film can provide information on the value for acceptance. To conclude the GafChromic film is a convenient and useful dosimetry tool for linac based radiosurgery.

  16. Accuracy evaluation of the optical surface monitoring system on EDGE linear accelerator in a phantom study.

    Science.gov (United States)

    Mancosu, Pietro; Fogliata, Antonella; Stravato, Antonella; Tomatis, Stefano; Cozzi, Luca; Scorsetti, Marta

    2016-01-01

    Frameless stereotactic radiosurgery (SRS) requires dedicated systems to monitor the patient position during the treatment to avoid target underdosage due to involuntary shift. The optical surface monitoring system (OSMS) is here evaluated in a phantom-based study. The new EDGE linear accelerator from Varian (Varian, Palo Alto, CA) integrates, for cranial lesions, the common cone beam computed tomography (CBCT) and kV-MV portal images to the optical surface monitoring system (OSMS), a device able to detect real-time patient׳s face movements in all 6 couch axes (vertical, longitudinal, lateral, rotation along the vertical axis, pitch, and roll). We have evaluated the OSMS imaging capability in checking the phantoms׳ position and monitoring its motion. With this aim, a home-made cranial phantom was developed to evaluate the OSMS accuracy in 4 different experiments: (1) comparison with CBCT in isocenter location, (2) capability to recognize predefined shifts up to 2° or 3cm, (3) evaluation at different couch angles, (4) ability to properly reconstruct the surface when the linac gantry visually block one of the cameras. The OSMS system showed, with a phantom, to be accurate for positioning in respect to the CBCT imaging system with differences of 0.6 ± 0.3mm for linear vector displacement, with a maximum rotational inaccuracy of 0.3°. OSMS presented an accuracy of 0.3mm for displacement up to 1cm and 1°, and 0.5mm for larger displacements. Different couch angles (45° and 90°) induced a mean vector uncertainty < 0.4mm. Coverage of 1 camera produced an uncertainty < 0.5mm. Translations and rotations of a phantom can be accurately detect with the optical surface detector system. PMID:26994827

  17. A semiempirical method for the description of off-center ratios at depth from linear accelerators

    International Nuclear Information System (INIS)

    A semiempirical method for the description of the off-center ratios (OCR) at depth from linear accelerators is presented, which is based on a method originally developed for cobalt-60 60Co units. The OCR profile is obtained as the sum of 2 components: the first describes an OCR similar to that from a 60Co unit, which approximates that resulting from the modification of the original x-ray intensity distribution by the flattening filter; the second takes into account the variable effect of the flattening filter on dose profile for different depths and field sizes, by considering the existence of a block and employing the negative field concept. The above method is formulated in a mathematical expression, where the parameters involved are obtained by fitting to the measured OCRs. Using this method, OCRs for various depths and field sizes, from a Philips SL-20 for the 6 MV x-ray beam and a Siemens Primus 23, for both the 6-MV and 23-MV x-ray beams, were reproduced with good accuracy. Furthermore, OCRs for other fields and depths that were not included in the fitting procedure were calculated using linear interpolation to estimate the values of the parameters. The results indicate that this method can be used to calculate OCR profiles for a wide range of depths and field sizes from a measured set of data and may be used for monitor unit calculations for off-axis points using a standard geometry. It may also be useful as a quality control tool to verify the accuracy of lacking profiles calculated by a treatment planning system

  18. Development of a dual-pulse RF driver for an S-band (= 2856 MHz) RF electron linear accelerator

    Science.gov (United States)

    Cha, Sungsu; Kim, Yujong; Lee, Byeong-No; Lee, Byung Cheol; Cha, Hyungki; Ha, Jang Ho; Park, Hyung Dal; Lee, Seung Hyun; Kim, Hui Su; Buaphad, Pikad

    2016-04-01

    The radiation equipment research division of Korea Atomic Energy Research Institute has developed a Container Inspection System (CIS) using a Radio Frequency (RF) electron linear accelerator for port security. The primary purpose of the CIS is to detect nuclear materials and explosives, as well country-specific prohibited substances, e.g., smuggled. The CIS consists of a 9/6 MeV dualenergy electron linear accelerator for distinguishing between organic and inorganic materials. The accelerator consists of an electron gun, an RF accelerating structure, an RF driver, a modulator, electromagnets, a cooling system, a X-ray generating target, X-ray collimator, a detector, and a container moving system. The RF driver is an important part of the configuration because it is the RF power source: it supplies the RF power to the accelerating structure. A unique aspect of the RF driver is that it generates dual RF power to generate dual energy (9/6 MeV). The advantage of this RF driver is that it can allow the pulse width to vary and can be used to obtain a wide range of energy output, and pulse repetition rates up to 300 Hz. For this reason, 140 W (5 MW - 9 MeV) and 37 W (3.4 MW - 6 MeV) power outputs are available independently. A high power test for 20 minutes demonstrate that stable dual output powers can be generated. Moreover, the dual power can be applied to the accelerator which has stable accelerator operation. In this paper, the design, fabrication and high power test of the RF driver for the RF electron linear accelerator (linac) are presented.

  19. An Analytic Linear Accelerator Source Model for Monte Carlo Dose Calculations. I. Model Representation and Construction

    CERN Document Server

    Tian, Zhen; Folkerts, Michael; Shi, Feng; Jiang, Steve B; Jia, Xun

    2015-01-01

    Monte Carlo (MC) simulation is considered as the most accurate method for radiation dose calculations. Accuracy of a source model for a linear accelerator is critical for the overall dose calculation accuracy. In this paper, we presented an analytical source model that we recently developed for GPU-based MC dose calculations. A key concept called phase-space-ring (PSR) was proposed. It contained a group of particles that are of the same type and close in energy and radial distance to the center of the phase-space plane. The model parameterized probability densities of particle location, direction and energy for each primary photon PSR, scattered photon PSR and electron PSR. For a primary photon PSRs, the particle direction is assumed to be from the beam spot. A finite spot size is modeled with a 2D Gaussian distribution. For a scattered photon PSR, multiple Gaussian components were used to model the particle direction. The direction distribution of an electron PSRs was also modeled as a 2D Gaussian distributi...

  20. Retrospective study on therapy options of brain metastases surgery versus stereotactic radiotherapy with the linear accelerator

    CERN Document Server

    Fortunati, M K S

    2001-01-01

    Background: in the therapy of brain metastases there has been a great progress in the last years. It was shown, that more aggressive therapies can not only extend the survival of the patients, but also improve quality of life. The major question of this study was, whether surgery or stereotactic radiotherapy with the linear accelerator show better results in behalf of the survival. Beside this major question many parameters regarding the patient or his primary cancer were examined. Methods: from the 1st of January 1995 until the 30th of June 2000 233 patients with one or more brain metastases have been treated in the Wagner Jauregg Landesnervenkrankenhaus Oberoesterreich (WJ LNKH OeO). The LINAC has been established on the 1st of July 1997. The patients have been distributed in three groups: 1. LINAC-group: 81 patients have been treated from the 1st of July 1997 until the 30th of June 2000 with the LINAC. 2. Surgery-group: 81 patients have been operated from the 1st of July 1997 until the 30th June 2000. 3 Co...