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. Induction linear accelerators

    Science.gov (United States)

    Birx, Daniel

    1992-03-01

    Among the family of particle accelerators, the Induction Linear Accelerator is the best suited for the acceleration of high current electron beams. Because the electromagnetic radiation used to accelerate the electron beam is not stored in the cavities but is supplied by transmission lines during the beam pulse it is possible to utilize very low Q (typicallymarriage of liner accelerator technology and nonlinear magnetic compressors has produced some unique capabilities. It now appears possible to produce electron beams with average currents measured in amperes, peak currents in kiloamperes and gradients exceeding 1 MeV/meter, with power efficiencies approaching 50%. The nonlinear magnetic compression technology has replaced the spark gap drivers used on earlier accelerators with state-of-the-art all-solid-state SCR commutated compression chains. The reliability of these machines is now approaching 1010 shot MTBF. In the following paper we will briefly review the historical development of induction linear accelerators and then discuss the design considerations.

  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. 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

  7. 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

  8. 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.

  9. 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.

  10. Development of unfolding energy spectrum with clinical linear accelerator based on transmission data

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hyun Joon; Park Hyo Jun; Yoo, Do Hyeon; Min, Chul Hee [Dept. of Radiation Convergence Engineering, Yonsei University, Seoul (Korea, Republic of); Kim, Byoung Chul; Yi, Chul Young [Center for Ionizing Radiation, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2016-05-15

    For the accurate dose assessment in radiation therapy, energy spectrum of the photon beam generated from the linac head is essential. The aim of this study is to develop the technique to accurately unfolding the energy spectrum with the transmission analysis method. Clinical linear accelerator and Monet Carlo method was employed to evaluate the transmission signals according to the thickness of the observer material, and then the response function of the ion chamber response was determined with the mono energy beam. Finally the energy spectrum was unfolded with HEPROW program. Elekta Synergy Flatform and Geant4 tool kits was used in this study. In the comparison between calculated and measured transmission signals using aluminum alloy as an attenuator, root mean squared error was 0.43%. In the comparison between unfolded spectrum using HEPROW program and calculated spectrum using Geant4, the difference of peak and mean energy were 0.066 and 0.03 MeV, respectively. However, for the accurate prediction of the energy spectrum, additional experiment with various type of material and improvement of the unfolding program is required. In this research, it is demonstrated that unfolding spectra technique could be used in megavoltage photon beam with aluminum alloy and HEPROW program.

  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. Berkeley Proton Linear Accelerator

    Science.gov (United States)

    Alvarez, L. W.; Bradner, H.; Franck, J.; Gordon, H.; Gow, J. D.; Marshall, L. C.; Oppenheimer, F. F.; Panofsky, W. K. H.; Richman, C.; Woodyard, J. R.

    1953-10-13

    A linear accelerator, which increases the energy of protons from a 4 Mev Van de Graaff injector, to a final energy of 31.5 Mev, has been constructed. The accelerator consists of a cavity 40 feet long and 39 inches in diameter, excited at resonance in a longitudinal electric mode with a radio-frequency power of about 2.2 x 10{sup 6} watts peak at 202.5 mc. Acceleration is made possible by the introduction of 46 axial "drift tubes" into the cavity, which is designed such that the particles traverse the distance between the centers of successive tubes in one cycle of the r.f. power. The protons are longitudinally stable as in the synchrotron, and are stabilized transversely by the action of converging fields produced by focusing grids. The electrical cavity is constructed like an inverted airplane fuselage and is supported in a vacuum tank. Power is supplied by 9 high powered oscillators fed from a pulse generator of the artificial transmission line type.

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

    Science.gov (United States)

    Zoubair, M.; El Bardouni, T.; El Gonnouni, L.; Boulaich, Y.; El Bakkari, B.; El Younoussi, C.

    2012-01-01

    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.

  14. 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)

  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 (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.

  16. 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

  17. 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

  18. 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

  19. Linear accelerator for radioisotope production

    Energy Technology Data Exchange (ETDEWEB)

    Hansborough, L.D.; Hamm, R.W.; Stovall, J.E.

    1982-02-01

    A 200- to 500-..mu..A 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-..mu..A 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-..mu..A beam, and the cost per beam watt on the target is less than half that of comparable cyclotrons.

  20. 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.

  1. 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...

  2. Repair of overheating linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Barkley, Walter; Baldwin, William; Bennett, Gloria; Bitteker, Leo; Borden, Michael; Casados, Jeff; Fitzgerald, Daniel; Gorman, Fred; Johnson, Kenneth; Kurennoy, Sergey; Martinez, Alberto; O’Hara, James; Perez, Edward; Roller, Brandon; Rybarcyk, Lawrence; Stark, Peter; Stockton, Jerry

    2004-01-01

    Los Alamos Neutron Science Center (LANSCE) is a proton accelerator that produces high energy particle beams for experiments. These beams include neutrons and protons for diverse uses including radiography, isotope production, small feature study, lattice vibrations and material science. The Drift Tube Linear Accelerator (DTL) is the first portion of a half mile long linear section of accelerator that raises the beam energy from 750 keV to 100 MeV. In its 31st year of operation (2003), the DTL experienced serious issues. The first problem was the inability to maintain resonant frequency at full power. The second problem was increased occurrences of over-temperature failure of cooling hoses. These shortcomings led to an investigation during the 2003 yearly preventative maintenance shutdown that showed evidence of excessive heating: discolored interior tank walls and coper oxide deposition in the cooling circuits. Since overheating was suspected to be caused by compromised heat transfer, improving that was the focus of the repair effort. Investigations revealed copper oxide flow inhibition and iron oxide scale build up. Acid cleaning was implemented with careful attention to protection of the base metal, selection of components to clean and minimization of exposure times. The effort has been very successful in bringing the accelerator through a complete eight month run cycle allowing an incredible array of scientific experiments to be completed this year (2003-2004). This paper will describe the systems, investigation analysis, repair, return to production and conclusion.

  3. 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)

  4. 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

  5. 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

  6. 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

  7. 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.

  8. 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)

  9. 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 ...

  10. 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

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 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....

  16. 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

  17. 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

  18. 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

  19. 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)

  20. 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

  1. 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

  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. Characterization of the primary source of electrons in linear accelerators in clinical use; Caracterizacion de la fuente primaria de electrones en aceleradores lineales de uso clinico

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Extremera, M.; Gonzalez Infantes, W.; Lallena rojo, A. M.; Anguiano Millan, M.

    2013-07-01

    Monte Carlo simulation is currently considered the most accurate method for calculations of doses due to electrons. The objective of the work is the characterization of the primary source of electrons from an accelerator of clinical use with Monte Carlo simulation, in order to build a model of sources involving a substantial saving of time of calculation in the simulation of treatment. (Author)

  4. 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

  5. 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...

  6. 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)

  7. 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 ...

  8. Linear Electron Accelerators For Radiation Processing. Current Status

    CERN Document Server

    Vorogushin, M F; Fialkovsky, A M; Fomin, L P; Gavrish, Y N; Klinov, A P; Maslennikov, O L; Naumov, S F; Nikolaev, V M; Shchepin, Yu P

    2004-01-01

    NPK LUTS NIIEFA has been developing linear accelerators for industrial applications during about 30 years. More than 150 linear accelerators for different applications have been manufactured by this company and installed in different regions of Russia and abroad. The linear accelerators for radiation sterilization developed in NPK LUTS NIIEFA are reviewed in this report.

  9. 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.

  10. Acceleration in Linear and Circular Motion

    Science.gov (United States)

    Kellington, S. H.; Docherty, W.

    1975-01-01

    Describes the construction of a simple accelerometer and explains its use in demonstrating acceleration, deceleration, constant speed, measurement of acceleration, acceleration and the inclined plane and angular and radial acceleration. (GS)

  11. 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.

  12. Vanguard industrial linear accelerator rapid product development

    Science.gov (United States)

    Harroun, Jim

    1994-07-01

    Siemens' ability to take the VanguardTM Industrial Linear Accelerator from the development stage to the market place in less than two years is described. Emphasis is on the development process, from the business plan through the shipment of the first commercial sale. Included are discussions on the evolution of the marketing specifications, with emphasis on imaging system requirements, as well as flexibility for expansion into other markets. Requirements used to create the engineering specifications, how they were incorporated into the design, and lessons learned from the demonstration system are covered. Some real-life examples of unanticipated problems are presented, as well as how they were resolved, including some discussion of the special problems encountered in developing a user interface and a training program for an international customer.

  13. Emittance growth in linear induction accelerators

    CERN Document Server

    Ekdahl, C A; Schulze, M E; Carlson, C A; Frayer, D K; Mostrum, C; Thoma, C H

    2014-01-01

    The Dual-Axis Radiographic Hydrotest (DARHT) facility uses bremsstrahlung radiation source spots produced by the focused electron beams from two linear induction accelerators (LIAs) to radiograph large hydrodynamic experiments driven by high explosives. Radiographic resolution is determined by the size of the source spot, and beam emittance is the ultimate limitation to spot size. On the DARHT Axis-II LIA we measure an emittance higher than predicted by theoretical simulations, and even though this axis produces sub-millimeter source spots, we are exploring ways to improve the emittance. Some of the possible causes for the discrepancy have been investigated using particle-in-cell (PIC) codes, although most of these are discounted based on beam measurements. The most likely source of emittance growth is a mismatch of the beam to the magnetic transport, which can cause beam halo.

  14. 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

  15. 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)

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Browne, J.C.

    1996-12-31

    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 tubes{close_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 tube{close_quotes} as the basic acceleration scheme using surplus 200 MHz radar components.

  3. 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

  4. 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.

  5. 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)

  6. 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.

  7. A beam-matching concept for medical linear accelerators

    DEFF Research Database (Denmark)

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

    2009-01-01

    The flexibility in radiotherapy can be improved if a patient can be moved between any one of the department's medical linear accelerators without the need to change anything in the patient's treatment plan. For this to be possible, the dosimetric characteristics of the various accelerators must...

  8. Detection of linear ego-acceleration from optic flow.

    Science.gov (United States)

    Festl, Freya; Recktenwald, Fabian; Yuan, Chunrong; Mallot, Hanspeter A

    2012-07-20

    Human observers are able to estimate various ego-motion parameters from optic flow, including rotation, translational heading, time-to-collision (TTC), time-to-passage (TTP), etc. The perception of linear ego-acceleration or deceleration, i.e., changes of translational velocity, is less well understood. While time-to-passage experiments indicate that ego-acceleration is neglected, subjects are able to keep their (perceived) speed constant under changing conditions, indicating that some sense of ego-acceleration or velocity change must be present. In this paper, we analyze the relation of ego-acceleration estimates and geometrical parameters of the environment using simulated flights through cylindrical and conic (narrowing or widening) corridors. Theoretical analysis shows that a logarithmic ego-acceleration parameter, called the acceleration rate ρ, can be calculated from retinal acceleration measurements. This parameter is independent of the geometrical layout of the scene; if veridical ego-motion is known at some instant in time, acceleration rate allows updating of ego-motion without further depth-velocity calibration. Results indicate, however, that subjects systematically confuse ego-acceleration with corridor narrowing and ego-deceleration with corridor widening, while veridically judging ego-acceleration in straight corridors. We conclude that judgments of ego-acceleration are based on first-order retinal flow and do not make use of acceleration rate or retinal acceleration.

  9. 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.

  10. 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

  11. Accelerating ab initio molecular dynamics simulations by linear prediction methods

    Science.gov (United States)

    Herr, Jonathan D.; Steele, Ryan P.

    2016-09-01

    Acceleration of ab initio molecular dynamics (AIMD) simulations can be reliably achieved by extrapolation of electronic data from previous timesteps. Existing techniques utilize polynomial least-squares regression to fit previous steps' Fock or density matrix elements. In this work, the recursive Burg 'linear prediction' technique is shown to be a viable alternative to polynomial regression, and the extrapolation-predicted Fock matrix elements were three orders of magnitude closer to converged elements. Accelerations of 1.8-3.4× were observed in test systems, and in all cases, linear prediction outperformed polynomial extrapolation. Importantly, these accelerations were achieved without reducing the MD integration timestep.

  12. 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.

  13. 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

  14. CHEBYSHEV ACCELERATION TECHNIQUE FOR SOLVING FUZZY LINEAR SYSTEM

    Directory of Open Access Journals (Sweden)

    S.H. Nasseri

    2009-10-01

    Full Text Available In this paper, Chebyshev acceleration technique is used to solve the fuzzy linear system (FLS. This method is discussed in details and followed by summary of some other acceleration techniques. Moreover, we show that in some situations that the methods such as Jacobi, Gauss-Sidel, SOR and conjugate gradient is divergent, our proposed method is applicable and the acquired results are illustrated by some numerical examples.

  15. 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...

  16. Modernization of the duoplasmatron of the I-2 linear accelerator

    CERN Document Server

    Kondratev, B K; Turchin, V I

    2004-01-01

    A modified ion source of the duoplasmatron type used in the I-2 linear accelerator for generating a proton beam is described. Improving the designs of the electrodes, the magnetic circuit, the gas-supply channel, and the electromagnetic valve has made it possible to considerably increase the service life of the source (up to 10**7 pulses), to reduce the consumption of hydrogen (up to 10 cm **3/h at a pulse repetition rate of 1 Hz), and to increase the stability and reliability of the source operation in the regime of everyday service of the linear accelerator in applied research as an injector of the ITEP U-10 proton synchrotron.

  17. 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.)

  18. Kinematics and hydrodynamics of linear acceleration in eels, Anguilla rostrata.

    Science.gov (United States)

    Tytell, Eric D

    2004-12-22

    The kinematics and hydrodynamics of routine linear accelerations were studied in American eels, Anguilla rostrata, using high-speed video and particle image velocimetry. Eels were examined both during steady swimming at speeds from 0.6 to 1.9 body lengths (L) per second and during accelerations from -1.4 to 1.3 L s(-2). Multiple regression of the acceleration and steady swimming speed on the body kinematics suggests that eels primarily change their tail-tip velocity during acceleration. By contrast, the best predictor of steady swimming speed is body wave speed, keeping tail-tip velocity an approximately constant fraction of the swimming velocity. Thus, during steady swimming, Strouhal number does not vary with speed, remaining close to 0.32, but during acceleration, it deviates from the steady value. The kinematic changes during acceleration are indicated hydrodynamically by axial fluid momentum in the wake. During steady swimming, the wake consists of lateral jets of fluid and has minimal net axial momentum, which reflects a balance between thrust and drag. During acceleration, those jets rotate to point downstream, adding axial momentum to the fluid. The amount of added momentum correlates with the acceleration, but is greater than the necessary inertial force by 2.8+/-0.6 times, indicating a substantial acceleration reaction.

  19. 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.

  20. 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

  1. 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)

  2. Spin dynamics in storage rings and linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Irwin, J.

    1994-04-01

    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.

  3. 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.

  4. 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)

  5. 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.)

  6. 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.

  7. 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.)

  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. 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.

  10. Challenges in the design of linear accelerator tunnels and services

    CERN Document Server

    Osborne, John

    2008-01-01

    Studies are well underway for the next generation of linear accelerators. The International Linear Collider (ILC) is working towards a maximum collision energy of 1 TeV and the Compact Linear Collider (CLIC) even higher at 3 TeV. Although the accelerating technologies are very different, many similarities can be found between the two projects from a civil engineering and technical services point of view. Both projects would require a site of approximately 50 km in length with stable geological conditions. CERN has been selected as one of the sample sites for the preliminary studies. The aim of this paper is to present the key challenges in the design of civil engineering and technical services such as cooling, ventilation and electricity that need to be overcome to realise such large scale projects in the future.

  11. 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...

  12. 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.

  13. 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)

  14. 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

  15. 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.

  16. Modernization of the duoplasmatron of the H-2 linear accelerator

    CERN Document Server

    Kondratev, B K; Turchin, V I

    2004-01-01

    A modified ion source of the duoplasmatron type used in the H-2 linear accelerator for generating a proton beam is described. Improving the designs of the electrodes, the magnetic circuit, the gas-supply channel, and the electromagnetic valve has made it possible to considerably increase the service life of the source (up to 10/sup 7/ pulses), to reduce the consumption of hydrogen (up to 10 cm/sup 3//h at a pulse repetition rate of 1 Hz), and to increase the stability and reliability of the source operation in the regime of everyday service of the linear accelerator in applied research as an injector of the ITEP U-10 proton synchrotron. (3 refs).

  17. 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

  18. 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 ...

  19. 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)

  20. 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...

  1. 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...

  2. 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.

  3. 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.

  4. 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.

  5. 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)

  6. Versatile Low Level RF System For Linear Accelerators

    Science.gov (United States)

    Potter, James M.

    2011-06-01

    The Low Level RF (LLRF) system is the source of all of the rf signals required for an rf linear accelerator. These signals are amplified to drive accelerator and buncher cavities. It can even provide the synchronizing signal for the rf power for a synchrotron. The use of Direct Digital Synthesis (DDS) techniques results in a versatile system that can provide multiple coherent signals at the same or different frequencies with adjustable amplitudes and phase relations. Pulsing the DDS allows rf switching with an essentially infinite on/off ratio. The LLRF system includes a versatile phase detector that allows phase-locking the rf frequency to a cavity at any phase angle over the full 360° range. With the use of stepper motor driven slug tuners multiple cavity resonant frequencies can be phase locked to the rf source frequency. No external phase shifters are required and there is no feedback loop phase setup required. All that is needed is to turn the frequency feedback on. The use of Digital Signal Processing (DSP) allows amplitude and phase control over the entire rf pulse. This paper describes the basic principles of a LLRF system that has been used for both proton accelerators and electron accelerators, including multiple tank accelerators, sub-harmonic and fundamental bunchers, and synchrotrons.

  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. Heterogenous Acceleration for Linear Algebra in Multi-coprocessor Environments

    Energy Technology Data Exchange (ETDEWEB)

    Luszczek, Piotr R [ORNL; Tomov, Stanimire Z [ORNL; Dongarra, Jack J [ORNL

    2015-01-01

    We present an efficient and scalable programming model for the development of linear algebra in heterogeneous multi-coprocessor environments. The model incorporates some of the current best design and implementation practices for the heterogeneous acceleration of dense linear algebra (DLA). Examples are given as the basis for solving linear systems' algorithms - the LU, QR, and Cholesky factorizations. To generate the extreme level of parallelism needed for the efficient use of coprocessors, algorithms of interest are redesigned and then split into well-chosen computational tasks. The tasks execution is scheduled over the computational components of a hybrid system of multi-core CPUs and coprocessors using a light-weight runtime system. The use of lightweight runtime systems keeps scheduling overhead low, while enabling the expression of parallelism through otherwise sequential code. This simplifies the development efforts and allows the exploration of the unique strengths of the various hardware components.

  9. 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.

  10. 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)

  11. Ion acceleration in a scalable MEMS RF-structure for a compact linear accelerator

    CERN Document Server

    Persaud, A; Feinberg, E; Seidl, P A; Waldron, W L; Lal, A; Vinayakumar, K B; Ardanuc, S; Schenkel, T

    2016-01-01

    A new approach for a compact radio-frequency(rf) accelerator structure is presented. The idea is based on the Multiple Electrostatic Quadrupole Array Linear Accelerator (MEQALAC) structure that was first developed in the 1980s. The MEQALAC allowed scaling of rf-structure down to dimensions of centimeters while at the same time allowing for higher beam currents through parallel beamlets. Using micro-electro-mechanical systems (MEMS) for highly scalable fabrication, we reduce the critical dimension to the sub-millimeter regime, while massively scaling up the potential number of parallel beamlets. The technology is based on rf-acceleration components and electrostatic quadrupoles (ESQs) implemented in a silicon wafer based design where each beamlet passes through beam apertures in the wafer. The complete accelerator is then assembled by stacking these wafers. This approach allows fast and cheap batch fabrication of the components and flexibility in system design for different applications. For prototyping these ...

  12. The general RF tuning for IH-DTL linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Y.R. [Key State Laboratory of Nuclear Physics and Technology, Peking University (China)], E-mail: yrlu@pku.edu.cn; Ratzinger, U. [Institute of Applied Physics, Frankfurt University (Germany); Schlitt, B. [Gesellschaft fuer Schwerionenforschung, mbH, Darmstadt (Germany); Tiede, R. [Institute of Applied Physics, Frankfurt University (Germany)

    2007-11-21

    The RF tuning is the most important research for achieving the resonant frequency and the flatness of electric field distributions along the axis of RF accelerating structures. The six different tuning concepts and that impacts on the longitudinal field distributions have been discussed in detail combining the RF tuning process of a 1:2 modeled 20.85 MV compact IH-DTL cavity, which was designed to accelerate proton, helium, oxygen or C{sup 4+} from 400 keV/u to 7 MeV/u and used as the linear injector of 430 MeV/u synchrotron [Y.R. Lu, S. Minaev, U. Ratzinger, B. Schlitt, R.Tiede, The Compact 20MV IH-DTL for the Heidelberg Therapy Facility, in: Proceedings of the LINAC Conference, Luebeck, Germany, 2004 ; Y.R. Lu, Frankfurt University Dissertation, 2005. ] in Heidelberg Heavy Ion Cancer Therapy (HICAT). Some of tuning concepts are also suitable and effective for the tuning of RFQ and/or other RF accelerating structures. Finally good field flatness in IH-DTL cavity has been realized successfully. The experience got from the model cavity tuning benefits real power cavity tuning, which is only needed to be tuned by the plungers. The cavity had a beam commissioning successfully for the initial beam acceleration at the end of 2006.

  13. The general RF tuning for IH-DTL linear accelerators

    Science.gov (United States)

    Lu, Y. R.; Ratzinger, U.; Schlitt, B.; Tiede, R.

    2007-11-01

    The RF tuning is the most important research for achieving the resonant frequency and the flatness of electric field distributions along the axis of RF accelerating structures. The six different tuning concepts and that impacts on the longitudinal field distributions have been discussed in detail combining the RF tuning process of a 1:2 modeled 20.85 MV compact IH-DTL cavity, which was designed to accelerate proton, helium, oxygen or C 4+ from 400 keV/ u to 7 MeV/u and used as the linear injector of 430 MeV/ u synchrotron [Y.R. Lu, S. Minaev, U. Ratzinger, B. Schlitt, R.Tiede, The Compact 20MV IH-DTL for the Heidelberg Therapy Facility, in: Proceedings of the LINAC Conference, Luebeck, Germany, 2004 [1]; Y.R. Lu, Frankfurt University Dissertation, 2005. [2

  14. 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

  15. 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.)

  16. 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

  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. 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)

  19. Acceleration in the linear non-scaling fixed-field alternating-gradient accelerator EMMA

    Science.gov (United States)

    Machida, S.; Barlow, R.; Berg, J. S.; Bliss, N.; Buckley, R. K.; Clarke, J. A.; Craddock, M. K.; D'Arcy, R.; Edgecock, R.; Garland, J. M.; Giboudot, Y.; Goudket, P.; Griffiths, S.; Hill, C.; Hill, S. F.; Hock, K. M.; Holder, D. J.; Ibison, M. G.; Jackson, F.; Jamison, S. P.; Johnstone, C.; Jones, J. K.; Jones, L. B.; Kalinin, A.; Keil, E.; Kelliher, D. J.; Kirkman, I. W.; Koscielniak, S.; Marinov, K.; Marks, N.; Martlew, B.; McIntosh, P. A.; McKenzie, J. W.; Méot, F.; Middleman, K. J.; Moss, A.; Muratori, B. D.; Orrett, J.; Owen, H. L.; Pasternak, J.; Peach, K. J.; Poole, M. W.; Rao, Y.-N.; Saveliev, Y.; Scott, D. J.; Sheehy, S. L.; Shepherd, B. J. A.; Smith, R.; Smith, S. L.; Trbojevic, D.; Tzenov, S.; Weston, T.; Wheelhouse, A.; Williams, P. H.; Wolski, A.; Yokoi, T.

    2012-03-01

    In a fixed-field alternating-gradient (FFAG) accelerator, eliminating pulsed magnet operation permits rapid acceleration to synchrotron energies, but with a much higher beam-pulse repetition rate. Conceived in the 1950s, FFAGs are enjoying renewed interest, fuelled by the need to rapidly accelerate unstable muons for future high-energy physics colliders. Until now a `scaling' principle has been applied to avoid beam blow-up and loss. Removing this restriction produces a new breed of FFAG, a non-scaling variant, allowing powerful advances in machine characteristics. We report on the first non-scaling FFAG, in which orbits are compacted to within 10mm in radius over an electron momentum range of 12-18MeV/c. In this strictly linear-gradient FFAG, unstable beam regions are crossed, but acceleration via a novel serpentine channel is so rapid that no significant beam disruption is observed. This result has significant implications for future particle accelerators, particularly muon and high-intensity proton accelerators.

  20. Accelerating sparse linear algebra using graphics processing units

    Science.gov (United States)

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

    2011-06-01

    The modern graphics processing unit (GPU) found in many standard personal computers is a highly parallel math processor capable of over 1 TFLOPS of peak computational throughput at a cost similar to a high-end CPU with excellent FLOPS-to-watt ratio. High-level sparse linear algebra operations are computationally intense, often requiring large amounts of parallel operations and would seem a natural fit for the processing power of the GPU. Our work is on a GPU accelerated implementation of sparse linear algebra routines. We present results from both direct and iterative sparse system solvers. 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. For example, the CPU is responsible for graph theory portion of the direct solvers while the GPU simultaneously performs the low level linear algebra routines.

  1. 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...

  2. Improving linear accelerator service response with a real- time electronic event reporting system.

    Science.gov (United States)

    Hoisak, Jeremy D P; Pawlicki, Todd; Kim, Gwe-Ya; Fletcher, Richard; Moore, Kevin L

    2014-09-08

    To track linear accelerator performance issues, an online event recording system was developed in-house for use by therapists and physicists to log the details of technical problems arising on our institution's four linear accelerators. In use since October 2010, the system was designed so that all clinical physicists would receive email notification when an event was logged. Starting in October 2012, we initiated a pilot project in collaboration with our linear accelerator vendor to explore a new model of service and support, in which event notifications were also sent electronically directly to dedicated engineers at the vendor's technical help desk, who then initiated a response to technical issues. Previously, technical issues were reported by telephone to the vendor's call center, which then disseminated information and coordinated a response with the Technical Support help desk and local service engineers. The purpose of this work was to investigate the improvements to clinical operations resulting from this new service model. The new and old service models were quantitatively compared by reviewing event logs and the oncology information system database in the nine months prior to and after initiation of the project. Here, we focus on events that resulted in an inoperative linear accelerator ("down" machine). Machine downtime, vendor response time, treatment cancellations, and event resolution were evaluated and compared over two equivalent time periods. In 389 clinical days, there were 119 machine-down events: 59 events before and 60 after introduction of the new model. In the new model, median time to service response decreased from 45 to 8 min, service engineer dispatch time decreased 44%, downtime per event decreased from 45 to 20 min, and treatment cancellations decreased 68%. The decreased vendor response time and reduced number of on-site visits by a service engineer resulted in decreased downtime and decreased patient treatment cancellations.

  3. 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.

  4. Cryogen free superconducting splittable quadrupole magnet for linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Kashikhin, V.S.; Andreev, N.; Kerby, J.; Orlov, Y.; Solyak, N.; Tartaglia, M.; Velev, G.; /Fermilab

    2011-09-01

    A new superconducting quadrupole magnet for linear accelerators was fabricated at Fermilab. The magnet is designed to work inside a cryomodule in the space between SCRF cavities. SCRF cavities must be installed inside a very clean room adding issues to the magnet design, and fabrication. The designed magnet has a splittable along the vertical plane configuration and could be installed outside of the clean room around the beam pipe previously connected to neighboring cavities. For more convenient assembly and replacement a 'superferric' magnet configuration with four racetrack type coils was chosen. The magnet does not have a helium vessel and is conductively cooled from the cryomodule LHe supply pipe and a helium gas return pipe. The quadrupole generates 36 T integrated magnetic field gradient, has 600 mm effective length, and the peak gradient is 54 T/m. In this paper the quadrupole magnetic, mechanical, and thermal designs are presented, along with the magnet fabrication overview and first test results.

  5. 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.

  6. Novel Approach to Linear Accelerator Superconducting Magnet System

    Energy Technology Data Exchange (ETDEWEB)

    Kashikhin, Vladimir; /Fermilab

    2011-11-28

    Superconducting Linear Accelerators include a superconducting magnet system for particle beam transportation that provides the beam focusing and steering. This system consists of a large number of quadrupole magnets and dipole correctors mounted inside or between cryomodules with SCRF cavities. Each magnet has current leads and powered from its own power supply. The paper proposes a novel approach to magnet powering based on using superconducting persistent current switches. A group of magnets is powered from the same power supply through the common, for the group of cryomodules, electrical bus and pair of current leads. Superconducting switches direct the current to the chosen magnet and close the circuit providing the magnet operation in a persistent current mode. Two persistent current switches were fabricated and tested. In the paper also presented the results of magnetic field simulations, decay time constants analysis, and a way of improving quadrupole magnetic center stability. Such approach substantially reduces the magnet system cost and increases the reliability.

  7. 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.

  8. Review of diagnostics for next generation linear accelerators

    CERN Document Server

    Ross, M

    2001-01-01

    New electron linac designs incorporate substantial advances in critical beam parameters such as beam loading and bunch length and will require new levels of performance in stability and phase space control. In the coming decade, e- (and e+) linacs will be built for a high power linear collider (TESLA, CLIC, JLC/NLC), for fourth generation X-ray sources (TESLA FEL, LCLS, Spring 8 FEL) and for basic accelerator research and development (Orion). Each project assumes significant instrumentation performance advances across a wide front. This review will focus on basic diagnostics for beam position and phase space monitoring. Research and development efforts aimed at high precision multi-bunch beam position monitors, transverse and longitudinal profile monitors and timing systems will be described.

  9. LIGA-fabricated compact mm-wave linear accelerator cavities.

    Energy Technology Data Exchange (ETDEWEB)

    Song, J.J.; Bajikar, S.S.; DeCarlo, F.; Kang, Y.W.; Kustom, R.L.; Mancini, D.C.; Nassiri, A.; Lai, B.; Feinerman, A.D.; White, V.

    1998-03-23

    Millimeter-wave rf cavities for use in linear accelerators, free-electron lasers, and mm-wave undulatory are under development at Argonne National Laboratory. Typical cavity dimensions are in the 1000 mm range, and the overall length of the accelerator structure, which consists of 30-100 cavities, is about 50-100 mm. An accuracy of 0.2% in the cavity dimensions is necessary in order to achieve a high Q-factor of the cavity. To achieve this these structures are being fabricated using deep X-ray lithography, electroforming, and assembly (LIGA). The first prototype cavity structures are designed for 108 GHz and 2p/3-mode operation. Input and output couplers are integrated with the cavity structures. The cavities are fabricated on copper substrates by electroforming copper into 1-mm-thick PMMA resists patterned by deep x-ray lithography and polishing the copper down to the desired thickness. These are fabricated separately and subsequently assembled with precision spacing and alignment using microspheres, optical fibers, or microfabricated spacers/alignment pieces. Details of the fabrication process, alignment, and assembly work are presented in here.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. Additional dose assessment from the activation of high-energy linear accelerators used in radiation therapy

    Directory of Open Access Journals (Sweden)

    Ateia Embarka

    2008-01-01

    Full Text Available It is well known that medical linear accelerators generate activation products when operated above certain electron (photon energies. The aim of the present work is to assess the activation behavior of a medium-energy radiotherapy linear accelerator by applying in situ gamma-ray spectrometry and dose measurements, and to estimate the additional dose to radiotherapy staff on the basis of these results. Spectral analysis was performed parallel to dose rate measurements in the isocenter of the linear accelerator, immediately after the termination of irradiation. The following radioisotopes were detected by spectral analysis: 28Al, 62Cu, 56Mn, 64Cu, 187W, and 57Ni. The short-lived isotopes such as 28Al and 62Cu are the most important factors of the clinical routine, while the contribution to the radiation dose of medium-lived isotopes such as 56Mn, 57Ni, 64Cu, and 187W increases during the working day. Measured dose rates at the isocenter ranged from 2.2 µSv/h to 10 µSv/h in various measuring points of interest for the members of the radiotherapy staff. Within the period of 10 minutes, the dose rate decreased to values of 0.8 µSv/h. According to actual workloads in radiotherapy departments, a realistic exposure scenario was set, resulting in a maximal additional annual whole body dose to the radiotherapy staff of about 3.5 mSv.

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. Portable X-Band Linear Electron Accelerators for Radiographic Applications

    CERN Document Server

    Saverskiy, Aleksandr J; Hernandez, Michael; Mishin, Andrey V; Skowbo, Dave

    2005-01-01

    The MINAC series portable linear electron accelerator systems designed and manufactured at American Science and Engineering, Inc. High Energy Systems Division (AS&E HESD) are discussed in this paper. Each system can be configured as either an X-ray or electron beam source. The powerful 4 MeV and 6 MeV linacs powered by a 1,5 MW magnetron permit operation in a dose rate range from 100 R/min at 80 cm to 600 R/min at 80 cm. Each MINAC is a self-contained source with radiation leakage outside of the X-ray head less than 0,1% of the maximum dose. Along with these systems a 1 MeV ultra compact MINAC has been successfully tested. The unit is available with radiation leakage less then 0.01% and permits producing X-ray beam in an energy range (1…2) MeV at a high output dose rate. Design and experimental parameters are presented. The common and system specific features are also discussed.

  20. 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)

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. 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 ...

  6. 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

  7. 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.

  8. 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.)

  9. 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.

  10. 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.

  11. 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

  12. 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)

  13. Acceleration of the direct reconstruction of linear parametric images using nested algorithms.

    Science.gov (United States)

    Wang, Guobao; Qi, Jinyi

    2010-03-01

    Parametric imaging using dynamic positron emission tomography (PET) provides important information for biological research and clinical diagnosis. Indirect and direct methods have been developed for reconstructing linear parametric images from dynamic PET data. Indirect methods are relatively simple and easy to implement because the image reconstruction and kinetic modeling are performed in two separate steps. Direct methods estimate parametric images directly from raw PET data and are statistically more efficient. However, the convergence rate of direct algorithms can be slow due to the coupling between the reconstruction and kinetic modeling. Here we present two fast gradient-type algorithms for direct reconstruction of linear parametric images. The new algorithms decouple the reconstruction and linear parametric modeling at each iteration by employing the principle of optimization transfer. Convergence speed is accelerated by running more sub-iterations of linear parametric estimation because the computation cost of the linear parametric modeling is much less than that of the image reconstruction. Computer simulation studies demonstrated that the new algorithms converge much faster than the traditional expectation maximization (EM) and the preconditioned conjugate gradient algorithms for dynamic PET.

  14. 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

  15. 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...

  16. 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.

  17. 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)

  18. 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

  19. 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

  20. 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

  1. 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.

  2. Accelerating R with high performance linear algebra libraries

    Directory of Open Access Journals (Sweden)

    Bogdan Oancea

    2015-09-01

    Full Text Available Linear algebra routines are basic building blocks for the statistical software. In this paper we analyzed how can we improve R performance for matrix computations. We benchmarked few matrix operations using the standard linear algebra libraries included in the R distribution and high performance libraries like OpenBLAS, GotoBLAS and MKL. Our tests showed the best results are obtained with the MKL library, the other two libraries having similar performances, but lower than MKL.

  3. 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)

  4. Beam dynamics design for uranium drift tube linear accelerator

    Science.gov (United States)

    Dou, Wei-Ping; He, Yuan; Lu, Yuan-Rong

    2014-07-01

    KONUS beam dynamics design of uranium DTL with LORASR code is presented. The 238U34+ beam, whose current is 5.0 emA, is accelerated from injection energy of 0.35 MeV/u to output energy of 1.30 MeV/u by IH-DTL operated at 81.25 MHz in HIAF project at IMP of CAS. It achieves a transmission efficiency of 94.95% with a cavity length of 267.8 cm. The optimization aims are the reduction of emittance growth, beam loss and project costs. Because of the requirements of CW mode operation, the designed average acceleration gradient is about 2.48 MV/m. The maximum axial field is 10.2 MV/m, meanwhile the Kilpatrick breakdown field is 10.56 MV/m at 81.25 MHz.

  5. 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.

  6. 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.

  7. 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...

  8. 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.

  9. 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.

  10. 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)

  11. Characteristic parameters of 6--21 MeV electron beams from a 21 MeV linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ghazi, M.S.A.L. (Department of Medical Physics, Thunder Bay Regional Cancer Centre, Ontario Cancer Treatment and Research Foundation, Thunder Bay, Ontario P7A 7T1, (Canada) Department of Physics, Lakehead University, Thunder Bay, Ontario P7B 5E1, (Canada) Lingman, D. Department of Medical Physics, Thunder Bay Regional Cancer Centre, Ontario Cancer Treatment and Research Foundation, Thunder Bay, Ontario P7A 7T1, (Canada) Department of Computer Science, Lakehead University, Thunder Bay, Ontario P7B 5E1, (Canada)); Gilbert, L.D. (Thekkumthala, J. Department of Medical Physics, Thunder Bay Regional Cancer Centre, Ontario Cancer Treatment and Research Foundation, Thunder Bay, Ontario P7A 7T1, (Canada))

    1991-07-01

    Dosimetry measurements have been carried out for the electron beams produced by a linear accelerator at energies 6, 8, 10, 14, 18, and 21 MeV. Characteristic parameters of the central axis dose distributions were derived and compared to corresponding values of electron beams from other accelerators in clinical use where such a comparison is appropriate. A comprehensive set of dosimetric parameters is provided for electron beam treatment planning. The data include central axis depth dose, range--energy parameters, beam penumbra and uniformity.

  12. 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...

  13. Fast online Monte Carlo-based IMRT planning for the MRI linear accelerator

    NARCIS (Netherlands)

    Bol, G.H.; Hissoiny, S.; Lagendijk, J. J. W.; Raaymakers, B. W.

    2012-01-01

    The MRI accelerator, a combination of a 6 MV linear accelerator with a 1.5 T MRI, facilitates continuous patient anatomy updates regarding translations, rotations and deformations of targets and organs at risk. Accounting for these demands high speed, online intensity-modulated radiotherapy (IMRT) r

  14. Characteristics of photon beams from Philips SL25 linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Palta, J.R.; Ayyangar, K.; Daftari, I.; Suntharalingam, N. (Department of Radiation Oncology, Bodine Center for Cancer Treatment, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania 19107 (US))

    1990-01-01

    The Philips SL25 accelerator is a multimodality machine offering asymmetric collimator jaws and a new type of beam bending and transport system. It produces photon beams, nominally at 6 and 25 MV, and a scattered electron beam with nine selectable energies between 4 and 22 MeV. Dosimetric characteristics for the 6- and 25-MV photon beams are presented with respect to field flatness, surface and depth dose characteristics, isodose distribution, field size factors for both open and wedged fields, and narrow beam transmission data in different materials.

  15. 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.

  16. Theoretical aspects of implementation of kilovoltage cone-beam CT onboard linear accelerator for image-guided radiotherapy.

    Science.gov (United States)

    Rodríguez Cordón, Marta; Ferrer Albiach, Carlos

    2009-08-01

    The main objective of image-guided radiation therapy (IGRT) equipment is to reduce and correct inherent errors in external radiotherapy processes. At the present time, there are different IGRT systems available, but here we will refer exclusively to the kilovoltage cone-beam CT onboard linear accelerator (CBkVCT) and the different aspects that, from a clinical point of view, should be taken into consideration before the implementation of this equipment.

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. Development of an automatic frequency measurement system for RF linear accelerator magnetrons

    Science.gov (United States)

    Cha, Sungsu; Kim, Yujong; Lee, Byeong-No; Joo, Youngwoo; Lee, Soo Min; Lee, Byung Cheol; Cha, Hyungki; Lee, Seung Hyun; Park, Hyung Dal; Song, Ki Beak

    2015-06-01

    An X-band [9300 MHz] magnetron frequency measurement system was developed for the electron linear accelerators at the Korean Atomic Energy Research Institute (KAERI). The measurement and the display of the RF frequency during the accelerator operation time is a crucial factor for continuous operation for two key reasons. Firstly, if the RF frequency of the magnetron is not known, then the amount of frequency tuning cannot be known, and the appropriate RF power cannot be supplied to the accelerating-structure. Second, values including the accelerating-structure's coolingwater temperature setting, the solenoid-magnet's cooling-water temperature setting, and the tuning of the source's (magnetron's) frequency can be undertaken because the RF frequency is used as the reference. A key component of the accelerator is the accelerating-structure. The volume of the accelerating-structure changes according to the environment's temperature; there, the resonance frequency of the accelerating-structure varies. When the resonance frequency of the accelerator is changed, the output becomes unstable, and a low beam energy is obtained. Accordingly, was developed a magnetron frequency-measuring device in order to stabilize the accelerator's operation. The results of the test demonstrate that the measurement's accurate up to 100 kHz, which enables the provision of an accurate RF power to the accelerating -structure. In this paper, we discuss the RF frequency measurement system for the magnetron to enable a more stable accelerator operation in a linac.

  2. LAPACKrc: Fast linear algebra kernels/solvers for FPGA accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Juan; Nunez, Rafael C, E-mail: juan.gonzalez@accelogic.co [Accelogic, 1830 Main Street, Suite 204, Weston, FL (United States)

    2009-07-01

    We present LAPACKrc, a family of FPGA-based linear algebra solvers able to achieve more than 100x speedup per commodity processor on certain problems. LAPACKrc subsumes some of the LAPACK and ScaLAPACK functionalities, and it also incorporates sparse direct and iterative matrix solvers. Current LAPACKrc prototypes demonstrate between 40x-150x speedup compared against top-of-the-line hardware/software systems. A technology roadmap is in place to validate current performance of LAPACKrc in HPC applications, and to increase the computational throughput by factors of hundreds within the next few years.

  3. 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

  4. Assessment Of Some Acceleration Schemes In The Solution Of Systems Of Linear Equations.

    Directory of Open Access Journals (Sweden)

    S. Azizu

    2015-06-01

    Full Text Available Abstract In this paper assessment of acceleration schemes in the solution of systems of linear equations has been studied. The iterative methods Jacobi Gauss-Seidel and SOR methods were incorporated into the acceleration scheme Chebyshev extrapolation Residual smoothing Accelerated gradient and Richardson Extrapolation to speed up their convergence. The Conjugate gradient methods of GMRES BICGSTAB and QMR were also assessed. The research focused on Banded systems Tridiagonal systems and Dense Symmetric positive definite systems of linear equations for numerical experiments. The experiments were based on the following performance criteria convergence number of iterations speed of convergence and relative residual of each method. Matlab version 7.0.1 was used for the computation of the resulting algorithms. Assessment of the numerical results showed that the accelerated schemes improved the performance of Jacobi Gauss-Seidel and SOR methods. The Chebyshev and Richardson acceleration methods converged faster than the conjugate gradient methods of GMRES MINRES QMR and BICGSTAB in general.

  5. 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.

  6. 2 MeV linear accelerator for industrial applications

    Science.gov (United States)

    Smith, Richard R.; Farrell, Sherman R.

    1997-02-01

    RPC Industries has developed a high average power scanned electron beam linac system for medium energy industrial processing, such as in-line sterilization. The parameters are: electron energy 2 MeV; average beam current 5.0 mA; and scanned width 0.5 meters. The control system features data logging and a Man-Machine Interface system. The accelerator is vertically mounted, the system height above the floor is 3.4 m, and the footprint is 0.9×1.2 meter2. The typical processing cell inside dimensions are 3.0 m by 3.5 m by 4.2 m high with concrete side walls 0.5 m thick above ground level. The equal exit depth dose is 0.73 gm cm-2. Additional topics that will be reported are: throughput, measurements of dose vs depth, dose uniformity across the web, and beam power by calorimeter and magnetic deflection of the beam.

  7. 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.)

  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. 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

  10. 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.)

  11. 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

  12. 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.

  13. 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)

  14. 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

  15. 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.)

  16. Optical Levitation of a Droplet under Linear Increase of Gravitational Acceleration

    OpenAIRE

    Kohira, Masahiro I.; Isomura, Akihiro; Magome, Nobuyuki; Mukai, Sadaatsu; Yoshikawa, Kenichi

    2005-01-01

    Optical levitation of a liquid droplet in gas phase was investigated under timedependent change of the gravitational acceleration with specific flight pattern of an airplane. Through multiple trials under linear increase of effective gravitational acceleration, we performed the experiment of ptical trapping of a droplet from 0.3g_0 to 0.9g_0, where g_0 = 9.8 m/s^2. During such change of the effective gravitational acceleration, the trapping position on a droplet with the radius of 14 μm ...

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. Non-linear eye movements during visual-vestibular interaction under body oscillation with step-mode lateral linear acceleration.

    Science.gov (United States)

    Mori, Shigeo; Katayama, Naomi

    2005-02-01

    We investigated visual-vestibular interactions in normal humans, where a constant speed of optokinetic stimulation was combined with whole body oscillation of lateral linear acceleration (10 m stroke). The acceleration mode was not sinusoidal, but rectangular (step). The pure optokinetic reflex (reference OKR) and the OKR under combined stimulation (combined OKR) were induced by a random-dot pattern projected onto a hemispherical dome-screen affixed to a chair on a linear accelerator. The translational vestibulo-ocular reflex (tVOR) was determined separately in the dark during acceleration-step oscillation. Since the tVOR was masked by the OKR under combined stimulation, the interaction was assessed as changes in combined-OKR velocity at two segments of opposing acceleration; in other words, tVOR directions identical to (agonistic) and opposite to (antagonistic) the OKR direction. When a moderate optokinetic stimulus-speed of 40 deg/s was combined with a moderate acceleration of 0.3 G (3.0 m/s2) as in Experiment 1 (N=10), the combined-OKR velocity always increased during the agonistic condition, and the motion of the visual pattern was perceived as slow and clear in this segment. On the other hand, during the antagonistic condition, the combined-OKR velocity either remained unchanged or increased moderately, and the motion of the visual pattern was sensed as fast and unclear. Notably, in most subjects, the velocity difference in combined-OKR between the agonistic and antagonistic conditions was around the value of the tVOR velocity. In five of the ten subjects who completed an additional test session with the acceleration level increased from 0.3 to 0.5 G (4.9 m/s2), similar findings were maintained individually, suggesting independent behavior of tVOR. Therefore, we hypothesized that the interaction could be direction-selective; in other words, both tVOR and OKR are additive during the agonistic condition, but tVOR is suppressed during the antagonistic condition

  2. Final Technical Report on "Proposed Physics Experiments for Laser-Driven Electron Linear Acceleration in a Dielectric Loaded Vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Byer, Robert L. [Professor of Applied Physics

    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

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. Development of an Automatic Frequency Control (AFC) System for RF Electron Linear Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Sungsu; Kim, Yujong; Lee, Byeong-No; Joo, Youngwoo; Lee, Soo Min; Lee, Byung Cheol; Cha, Hyungki [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Hyung Dal [Radiation Technology eXcellence, Daejeon (Korea, Republic of); Lee, Seung Hyun [Sungkyunkwan University, Suwon (Korea, Republic of)

    2015-10-15

    In this paper, the design, fabrication, and RF power test of the AFC system for the X-band linac are presented. The main function of the AFC system is automatically matching of the resonance frequency of the accelerating structure and the RF frequency of the magnetron. For the frequency tuning, a fine tuning of 10 kHz is possible by rotating the tuning shaft with a rotation of 0.72 degree per pulse. Therefore, the frequency deviation is about 0.01%, and almost full RF power (2.1 MW) transmission was obtained because the reflected power is minimized. The Radiation Equipment Research Division of the Korea Atomic Energy Research Institute has been developing and upgrading a medical/industrial X-band RF electron linear accelerators. The medical compact RF electron linear accelerator consists of an electron gun, an acceleration tube (accelerating structure), two solenoid magnets, two steering magnets, a magnetron, modulator, an automatic frequency control (AFC) system, and an X-ray generating target. The accelerating structure of the component is composed of oxygen-free high-conductivity copper (OFHC). Therefore, the volume of the structure, hence, its resonance frequency can easily be changeable if the ambient temperature and pressure are changed. If the RF frequency of the 9300 MHz magnetron and the resonance frequency of accelerating structure are not matched, performance of the structure can be degraded. An AFC system is automatically matched with the RF frequency of the magnetron and resonance frequency of the accelerating structure, which obtained a high output power and reliable accelerator operation.

  9. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Liang, E-mail: luliang@riken.jp [Institute of Modern Physics, 509 Nanchang Road, Lanzhou 730000 (China); Riken Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Hattori, Toshiyuki [National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi 263-8555 (Japan); Hayashizaki, Noriyosu [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, N1-25 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8550 (Japan); Ishibashi, Takuya [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Okamura, Masahiro [Brookhaven National Laboratory, Upton, NY 11973 (United States); Kashiwagi, Hirotsugu [Japan Atomic Energy Research Institute, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Takeuchi, Takeshi [Accelerator Engineering Corporation, 301, 6-18-1 Konakadai, Inage-ku, Chiba 263-0043 (Japan); Zhao, Hongwei; He, Yuan [Institute of Modern Physics, 509 Nanchang Road, Lanzhou 730000 (China)

    2013-11-21

    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 CO{sub 2}-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 C{sup 4+}. 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.

  11. 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).

  12. 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...

  13. 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.

  14. Third party EPID with IGRT capability retrofitted onto an existing medical linear accelerator.

    Science.gov (United States)

    Odero, D O; Shimm, D S

    2009-07-01

    Radiation therapy requires precision to avoid unintended irradiation of normal organs. Electronic Portal Imaging Devices (EPIDs), can help with precise patient positioning for accurate treatment. EPIDs are now bundled with new linear accelerators, or they can be purchased from the Linac manufacturer for retrofit. Retrofitting a third party EPID to a linear accelerator can pose challenges. The authors describe a relatively inexpensive third party CCD camera-based EPID manufactured by TheraView (Cablon Medical B.V.), installed onto a Siemens Primus linear accelerator, and integrated with a Lantis record and verify system, an Oldelft simulator with Digital Therapy Imaging (DTI) unit, and a Philips ADAC Pinnacle treatment planning system (TPS). This system integrates well with existing equipment and its software can process DICOM images from other sources. The system provides a complete imaging system that eliminates the need for separate software for portal image viewing, interpretation, analysis, archiving, image guided radiation therapy and other image management applications. It can also be accessed remotely via safe VPN tunnels. TheraView EPID retrofit therefore presents an example of a less expensive alternative to linear accelerator manufacturers' proprietary EPIDs suitable for implementation in third world countries radiation therapy departments which are often faced with limited financial resources.

  15. 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.

  16. 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)

  17. ARIEL e-linac. Electron linear accelerator for photo-fission

    Science.gov (United States)

    Koscielniak, Shane

    2014-01-01

    The design and implementation of a 1/2 MW beam power electron linear accelerator (e-linac) for the production of rare isotope beams (RIB) via photo-fission in the context of the Advanced Rare IsotopE Laboratory, ARIEL (Koscielniak et al. 2008; Merminga et al. 2011; Dilling et al., Hyperfine Interact, 2013), is described. The 100 % duty factor e-linac is based on super-conducting radiofrequency (SRF) technology at 1.3 GHz and has a nominal energy of 50 MeV. This paper provides an overview of the accelerator major components including the gun, cryomodules and cryoplant, high power RF sources, and machine layout including beam lines. Design features to facilitate operation of the linac as a Recirculating Linear Accelerator (RLA) for various applications, including Free Electron Lasers, are also noted.

  18. Prototyping a large field size IORT applicator for a mobile linear accelerator

    Science.gov (United States)

    Janssen, Rogier W. J.; Faddegon, Bruce A.; Dries, Wim J. F.

    2008-04-01

    The treatment of large tumors such as sarcomas with intra-operative radiotherapy using a Mobetron® is often complicated because of the limited field size of the primary collimator and the available applicators (max Ø100 mm). To circumvent this limitation a prototype rectangular applicator of 80 × 150 mm2 was designed and built featuring an additional scattering foil located at the top of the applicator. Because of its proven accuracy in modeling linear accelerator components the design was based on the EGSnrc Monte Carlo simulation code BEAMnrc. First, the Mobetron® treatment head was simulated both without an applicator and with a standard 100 mm applicator. Next, this model was used to design an applicator foil consisting of a rectangular Al base plate covering the whole beam and a pyramid of four stacked cylindrical slabs of different diameters centered on top of it. This foil was mounted on top of a plain rectangular Al tube. A prototype was built and tested with diode dosimetry in a water tank. Here, the prototype showed clinically acceptable 80 × 150 mm2 dose distributions for 4 MeV, 6 MeV and 9 MeV, obviating the use of complicated multiple irradiations with abutting field techniques. In addition, the measurements agreed well with the MC simulations, typically within 2%/1 mm.

  19. 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

  20. 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.

  1. Energy shaping non-linear acceleration control for a pendulum-type mobility and experimental verification

    Science.gov (United States)

    Yokoyama, Kazuto; Takahashi, Masaki

    2015-02-01

    A dynamics-based non-linear controller with energy shaping to accelerate a pendulum-type mobility is proposed. The concept of this study is to control translational acceleration of the vehicle in a dynamically reasonable manner. The body angle is controlled to maintain a reference state where the vehicle is statically unstable but dynamically stable, which leads to a constant translational acceleration due to instability of the system. The accelerating motion is like a sprinter moving from crouch start and it fully exploits dynamics of the vehicle. To achieve it, the total energy of the system is shaped to have the minimum at a given reference state and the system is controlled to converge to it. The controller can achieve various properties through the energy shaping procedure. Especially, an energy function that will lead to safe operation of the vehicle is proposed. The effectiveness of the controller is verified in simulations and experiments.

  2. 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.

  3. 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

  4. 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

  5. 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,...

  6. Accelerated partial breast irradiation. Techniques and clinical implementation. 2. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Wazer, David E. [Tufts Medical Center, Boston, MA (United States). Dept. of Radiation Oncology; Arthur, Douglas W. [Virginia Commonwealth Univ., Richmond, VA (United States). Dept. of Radiation Oncology; Vicini, Frank, A. (eds.) [William Beaumont Hospital, Royal Oak, MI (United States). Dept. of Radiation Oncology

    2009-07-01

    Accelerated partial breast irradiation (APBI) is being rapidly introduced into the clinical management of early breast cancer. APBI, in fact, encompasses a number of different techniques and approaches that include brachytherapy, intraoperative, and external beam techniques. There is currently no single source that describes these techniques and their clinical implementation. This text is a concise handbook designed to assist the clinician in the implementation of APBI. This includes a review of the principles that underlie APBI, a practical and detailed description of each technique for APBI, a review of current clinical results of APBI, and a review of the incidence and management of treatment related complications. (orig.)

  7. 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

  8. 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

  9. 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...

  10. 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

  11. The vestibular evoked response to linear, alternating, acceleration pulses without acoustic masking as a parameter of vestibular function

    NARCIS (Netherlands)

    Oei, MLYM; Segenhout, JM; Wit, HP; Albers, FWJ

    2001-01-01

    In this study, short latency vestibular evoked potentials (VsEPs) were recorded in five guinea pigs in response to alternating linear acceleration pulses with and without acoustic masking. A steel bolt was implanted in the skull and coupled to a shaker. Linear acceleration pulses (n = 400) in upward

  12. 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...

  13. 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

  14. [Evaluation of a risk communication approach for maintenance staff working with induced radioactivity in medical linear accelerators].

    Science.gov (United States)

    Watanabe, Hiroshi; Yamaguchi, Ichiro; Maehara, Yoshiaki; Koizumi, Mitsue; Fujibuchi, Toshioh; Kida, Tetsuo; Tsukamoto, Atsuko; Horitsugi, Genki; Hiraki, Hitoshi; Kimura, Yumi; Oyama, Masaya

    2013-12-01

    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 (Papproach suggests that consensus building should be used to make rules on decommissioning operations for linear medical accelerators.

  15. 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.

  16. 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.

  17. 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.

  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. Optical Levitation of a Droplet under Linear Increase of Gravitational Acceleration

    CERN Document Server

    Kohira, M I; Magome, N; Mukai, S; Yoshikawa, K; Kohira, Masahiro I.; Isomura, Akihiro; Magome, Nobuyuki; Mukai, Sadaatsu; Yoshikawa, Kenichi

    2005-01-01

    Optical levitation of a liquid droplet in gas phase was investigated under timedependent change of the gravitational acceleration with specific flight pattern of an airplane. Through multiple trials under linear increase of effective gravitational acceleration, we performed the experiment of ptical trapping of a droplet from 0.3g_0 to 0.9g_0, where g_0 = 9.8 m/s^2. During such change of the effective gravitational acceleration, the trapping position on a droplet with the radius of 14 μm was found to be lowered by ca. 100 μm. The essential feature of the change of the trapping position is reproduced by a theoretical calculation under the framework of ray optics. As far as we know, the present study is the first report on optical levitation under time-dependent gravitational change.

  20. 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

  1. 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.

  2. 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

  3. Survey and Alignment of the 100MeV Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Park, Bumsik; Kwon, Hyeokjung; Jang, Jiho; Kim, Hansung; Kim, Daeil; Cho, Yongsub [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    The 100MeV linear accelerator was installed and under commissioning at the Gyeongju site. The 100MeV proton linac was developed by the KOMAC according to the survey work and the alignment process. 100MeV proton beam will be supplied to the users after the beam commissioning. KOMAC is developing a 100MeV high-duty-factor proton linac. Linac is composed with a 50keV proton injector, a 3MeV RFQ, DTL tanks and a beam dump. In this paper, the survey and alignment scheme are described. To install the accelerator, the align network was built and the survey work was accomplished. On the basis of the survey result, all of the accelerator components were installed in the tunnel with two laser trackers.

  4. 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...

  5. 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 ...

  6. An Energy Feedback System for the MIT/Bates Linear Accelerator

    CERN Document Server

    Barkhuff, D H; Averett, T; Beck, D H; Beise, E J; Cheever, D; Dodson, G; Kowalski, S; McKeown, R D; Müller, B A; Pitt, M L; Spayde, D T; Tschalär, C; Zolfaghari, A

    2000-01-01

    We report the development and implementation of an energy feedback system for the MIT/Bates Linear Accelerator Center. General requirements of the system are described, as are the specific requirements, features, and components of the system unique to its implementation at the Bates Laboratory. We demonstrate that with the system in operation, energy fluctuations correlated with the 60 Hz line voltage and with drifts of thermal origin are reduced by an order of magnitude.

  7. An Energy Feedback System for the MIT/Bates Linear Accelerator

    OpenAIRE

    Barkhuff, D. H.; Wells, S. P.; Averett, T.; Beck, D. H.; Beise, E.J.; Cheever, D.; Dodson, G.; Kowalski, S.; McKeown, R. D.; Mueller, B.A.; M. Pitt; Spayde, D; Tschalaer, C.; Zolfaghari, A.

    1999-01-01

    We report the development and implementation of an energy feedback system for the MIT/Bates Linear Accelerator Center. General requirements of the system are described, as are the specific requirements, features, and components of the system unique to its implementation at the Bates Laboratory. We demonstrate that with the system in operation, energy fluctuations correlated with the 60 Hz line voltage and with drifts of thermal origin are reduced by an order of magnitude.

  8. Mitigation of ground motion effects in linear accelerators via feed-forward control

    OpenAIRE

    Pfingstner, J.; Artoos, K.; Charrondiere, C.; Janssens, St.; Patecki, M.; Renier, Y.; Schulte, D.; Tomás, R.; Jérémie, A.; Kubo, K; Kuroda, S.; Naito, T.; Okugi, T.; Tauchi, T.; Terunuma, N.

    2014-01-01

    International audience; Ground motion is a severe problem for many particle accelerators, since it excites beam oscillations, which decrease the beam quality and create beam-beam offset (at colliders). Orbit feedback systems can only compensate ground motion effects at frequencies significantly smaller than the beam repetition rate. In linear colliders, where the repetition rate is low, additional counter measures have to be put in place. For this reason, a ground motion mitigation method bas...

  9. 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 ...

  10. 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.

  11. 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....

  12. 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

  13. 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

  14. 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

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

    Directory of Open Access Journals (Sweden)

    K. Abdul Haneefa

    2014-01-01

    Full Text Available 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 (SSD in 50 × 50 × 50 cm3 PTW water phantom using 0.12 cc cylindrical ionization chamber. Percentage depth dose for standard square field sizes and dose profiles for various depths are studied in detail. The analysis was carried out using ROOT (a DATA analysis frame work developed at CERN system. Simulation result shows good agreement in percentage depth dose and beam profiles with the experimental measurements for Varian Clinac iX dual energy medical linear accelerator.

  16. 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.

  17. 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)

  18. 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

  19. 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.

  20. 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

  1. Design and test of a superconducting magnet in a linear accelerator for an Accelerator Driven Subcritical System

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Quanling, E-mail: pengql@ihep.ac.cn [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Xu, Fengyu [Harbin Institute of Technology, Heilongjiang 150006 (China); Wang, Ting [Beijing Huantong Special Equipment Co., LTD, Beijing 100192 (China); Yang, Xiangchen [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Chen, Anbin [Harbin Institute of Technology, Heilongjiang 150006 (China); Wei, Xiaotao [Beijing Huantong Special Equipment Co., LTD, Beijing 100192 (China); Gao, Yao; Hou, Zhenhua; Wang, Bing; Chen, Yuan; Chen, Haoshu [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2014-11-11

    A batch superconducting solenoid magnet for the ADS proton linear accelerator has been designed, fabricated, and tested in a vertical dewar in Sept. 2013. A total of ten superconducting magnets will be installed into two separate cryomodules. Each cryomodule contains six superconducting spoke RF cavities for beam acceleration and five solenoid magnets for beam focusing. The multifunction superconducting magnet contains a solenoid for beam focusing and two correctors for orbit correction. The design current for the solenoid magnet is 182 A. A quench performance test shows that the operating current of the solenoid magnet can reach above 300 A after natural quenching on three occasions during current ramping (260 A, 268 A, 308 A). The integrated field strength and leakage field at the nearby superconducting spoke cavities all meet the design requirements. The vertical test checked the reliability of the test dewar and the quench detection system. This paper presents the physical and mechanical design of the batch magnets, the quench detection technique, field measurements, and a discussion of the residual field resulting from persistent current effects.

  2. 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.

  3. Acceleration of multiple solution of a boundary value problem involving a linear algebraic system

    Science.gov (United States)

    Gazizov, Talgat R.; Kuksenko, Sergey P.; Surovtsev, Roman S.

    2016-06-01

    Multiple solution of a boundary value problem that involves a linear algebraic system is considered. New approach to acceleration of the solution is proposed. The approach uses the structure of the linear system matrix. Particularly, location of entries in the right columns and low rows of the matrix, which undergo variation due to the computing in the range of parameters, is used to apply block LU decomposition. Application of the approach is considered on the example of multiple computing of the capacitance matrix by method of moments used in numerical electromagnetics. Expressions for analytic estimation of the acceleration are presented. Results of the numerical experiments for solution of 100 linear systems with matrix orders of 1000, 2000, 3000 and different relations of variated and constant entries of the matrix show that block LU decomposition can be effective for multiple solution of linear systems. The speed up compared to pointwise LU factorization increases (up to 15) for larger number and order of considered systems with lower number of variated entries.

  4. X-ray beam hardening correction for measuring density in linear accelerator industrial computed tomography

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ri-Feng; WANG Jue; CHEN Wei-Min

    2009-01-01

    Due to X-ray attenuation being approximately proportional to material density, it is possible to measure the inner density through Industrial Computed Tomography (ICT) images accurately. In practice, however, a number of factors including the non-linear effects of beam hardening and diffuse scattered radia-tion complicate the quantitative measurement of density variations in materials. This paper is based on the linearization method of beam hardening correction, and uses polynomial fitting coefficient which is obtained by the curvature of iron polychromatic beam data to fit other materials. Through theoretical deduction, the paper proves that the density measure error is less than 2% if using pre-filters to make the spectrum of linear accelerator range mainly 0.3 MeV to 3 MeV. Experiment had been set up at an ICT system with a 9 MeV electron linear accelerator. The result is satisfactory. This technique makes the beam hardening correction easy and simple, and it is valuable for measuring the ICT density and making use of the CT images to recognize materials.

  5. Mitigation of ground motion effects in linear accelerators via feed-forward control

    Science.gov (United States)

    Pfingstner, J.; Artoos, K.; Charrondiere, C.; Janssens, St.; Patecki, M.; Renier, Y.; Schulte, D.; Tomás, R.; Jeremie, A.; Kubo, K.; Kuroda, S.; Naito, T.; Okugi, T.; Tauchi, T.; Terunuma, N.

    2014-12-01

    Ground motion is a severe problem for many particle accelerators, since it excites beam oscillations, which decrease the beam quality and create beam-beam offset (at colliders). Orbit feedback systems can only compensate ground motion effects at frequencies significantly smaller than the beam repetition rate. In linear colliders, where the repetition rate is low, additional counter measures have to be put in place. For this reason, a ground motion mitigation method based on feed-forward control is presented in this paper. It has several advantages compared to other techniques (stabilization systems and intratrain feedback systems) such as cost reduction and potential performance improvement. An analytical model is presented that allows the derivation of hardware specification and performance estimates for a specific accelerator and ground motion model. At the Accelerator Test Facility (ATF2), ground motion sensors have been installed to verify the feasibility of important parts of the mitigation strategy. In experimental studies, it has been shown that beam excitations due to ground motion can be predicted from ground motion measurements on a pulse-to-pulse basis. Correlations of up to 80% between the estimated and measured orbit jitter have been observed. Additionally, an orbit jitter source was identified and has been removed, which halved the orbit jitter power at ATF2 and shows that the feed-forward scheme is also very useful for the detection of installation issues. We believe that the presented mitigation method has the potential to reduce costs and improve the performance of linear colliders and potentially other linear accelerators.

  6. 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.

  7. 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.

  8. 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.

  9. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Thatcher, T; Madsen, S; Sudowe, R [University of Nevada, Las Vegas, Las Vegas, NV (United States); Meigooni, A Soleimani [University of Nevada, Las Vegas, Las Vegas, NV (United States); Comprehensive Cancer Center of Nevada, Las Vegas, Nevada (United States)

    2015-06-15

    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.

  11. 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

  12. 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.

  13. Evaluation of source term induced by beam loss in the superconducting linear accelerator at RAON

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Jin; Kim, Su Na; Nam, Shin Woo; Chung, Yon Sei [Rare Isotope Science Project, Institute for Basic Science, Daejeon (Korea, Republic of)

    2014-11-15

    As a new world-class heavy ion accelerator, RAON is able to accelerate heavy ions from proton to uranium with the energy up to -400 MeV/u and produce rare isotopes. These high purity, high intensity, and high energy beams generate the various secondary radiation which will impact on the shielding aspects of the main linear accelerator tunnels. In the main tunnel the secondary neutrons are produced by uniform beam-loss or accident criteria. In this paper evaluations of several source terms induced by beam-loss will be discussed along with the physics model of the Monte Carlo simulation codes. The beam-loss criteria were tested for the evaluation of source term for the main beam line tunnel of the RAON accelerator. It was found that the amount of the secondary neutrons depends on the incident angle of projectile on the beam pipe and the mass and energy of projectile. The influence of selected physics models and libraries of MCNPX and PHITS has been examined. The secondary neutrons were produced most in the CEM and LAQGSM model.

  14. 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.

  15. 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

  16. Dosimetric aspects of the therapeutic photon beams from a dual-energy linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ghazi, M.S.A.L.; Arjune, B.; Fiedler, J.A.; Sharma, P.D.

    1988-03-01

    Parameters of the photon beams (6 and 20 MV) from a dual-energy linear accelerator (Mevatron-KD, Siemens Medical Laboratories, CA) are presented. The depth dose characteristics of the photon beams are d/sub max/ of 1.8 and 3.8 cm and percentage depth dose of 68% and 80% at 10-cm depth and 100-cm source--surface distance for a field size of 10 x 10 cm/sup 2/ for 6 and 20 MV, respectively. The 6 and 20 MV beams were found to correspond to nominal accelerating potentials of 4.7 and 17 MV, respectively. The stability of output is within +- 1% and flatness and symmetry are within +- 3%. These figures compare favorably with the manufacturer's specifications.

  17. Power System Design Compromises for Large-Scale Linear Particle Accelerators

    CERN Document Server

    Papastergiou, K D

    2014-01-01

    This paper discusses various design aspects of a 280MW Power System for the Compact Linear Collider (CLIC), a 50km long electrons-positrons accelerator, under feasibility evaluation. The key requirements are a very high accelerator availability and constant power flow from the utility grid, considering the pulsed power nature of CLIC. Firstly, the possible power network and cabling layouts are discussed along with potential difficulties on electrical fault clearance. Following, the use of active front-end converters is examined as a means to control the power flow and power quality seen by the 400kV grid. In particular a modular multilevel converter preliminary configuration is described and the compromises related to energy storage and voltage level are discussed.

  18. Parameter choices for a muon recirculating linear accelerator from 5 to 63 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Berg, J. S. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2014-06-19

    A recirculating linear accelerator (RLA) has been proposed to accelerate muons from 5 to 63 GeV for a muon collider. It should be usable both for a Higgs factory and as a stage for a higher energy collider. First, the constraints due to the beam loading are computed. Next, an expression for the longitudinal emittance growth to lowest order in the longitudinal emittance is worked out. After finding the longitudinal expression, a simplified model that describes the arcs and their approximate expression for the time of flight dependence on energy in those arcs is found. Finally, these results are used to estimate the parameters required for the RLA arcs and the linac phase.

  19. A review of vector convergence acceleration methods, with applications to linear algebra problems

    Science.gov (United States)

    Brezinski, C.; Redivo-Zaglia, M.

    In this article, in a few pages, we will try to give an idea of convergence acceleration methods and extrapolation procedures for vector sequences, and to present some applications to linear algebra problems and to the treatment of the Gibbs phenomenon for Fourier series in order to show their effectiveness. The interested reader is referred to the literature for more details. In the bibliography, due to space limitation, we will only give the more recent items, and, for older ones, we refer to Brezinski and Redivo-Zaglia, Extrapolation methods. (Extrapolation Methods. Theory and Practice, North-Holland, 1991). This book also contains, on a magnetic support, a library (in Fortran 77 language) for convergence acceleration algorithms and extrapolation methods.

  20. 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)

  1. 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.

  2. Dosimetric characteristics of a 6 MV photon beam from a linear accelerator with asymmetric collimator jaws

    Energy Technology Data Exchange (ETDEWEB)

    Palta, J.R.; Ayyangar, K.M.; Suntharalingam, N.

    1988-02-01

    Dosimetric measurements have been made of a 6 MV photon beam from a linear accelerator equipped with asymmetric jaws. The field size factors for asymmetrically set fields are compared to those for symmetrically set fields. The change of beam quality has been measured as a function of off-axis position of the asymmetric fields to assess its effect on depth dose. Additional measurements include beam penumbra and shape of isodose curves for open and wedge fields as the field opening is moved asymmetrically from the central ray.

  3. 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)

  4. 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

  5. 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)

  6. 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.)

  7. 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.

  8. 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

  9. 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

  10. Multi-cavity complex controller with vector simulator for TESLA technology linear accelerator

    Science.gov (United States)

    Czarski, Tomasz; Pozniak, Krzysztof T.; Romaniuk, Ryszard S.; Szewinski, Jaroslaw

    2008-01-01

    A digital control, as the main part of the Low Level RF system, for superconducting cavities of a linear accelerator is presented. The FPGA based controller, supported by MATLAB system, was developed to investigate a novel firmware implementation. The complex control algorithm based on the non-linear system identification is the proposal verified by the preliminary experimental results. The general idea is implemented as the Multi-Cavity Complex Controller (MCC) and is still under development. The FPGA based controller executes procedure according to the prearranged control tables: Feed-Forward, Set-Point and Corrector unit, to fulfill the required cavity performance: driving in the resonance during filling and field stabilization for the flattop range. Adaptive control algorithm is applied for the feed-forward and feedback modes. The vector Simulator table has been introduced for an efficient verification of the FPGA controller structure. Experimental results of the internal simulation, are presented for a cavity representative condition.

  11. 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.

  12. 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。

  13. 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

  14. 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.

  15. 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.

  16. 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...

  17. 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

  18. 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

  19. 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.

  20. 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)

  1. Why most traumatic brain injuries are not caused by linear acceleration but skull fractures are.

    Directory of Open Access Journals (Sweden)

    Svein eKleiven

    2013-11-01

    Full Text Available Injury statistics have found the most common accident situation to be an oblique impact. An oblique impact will give rise to both linear and rotational head kinematics. The human brain is most sensitive to rotational motion. The bulk modulus of brain tissue is roughly five to six orders of magnitude larger than the shear modulus so that for a given impact it tends to deform predominantly in shear. This gives a large sensitivity of the strain in the brain to rotational loading and a small sensitivity to linear kinematics. Therefore, rotational kinematics should be a better indicator of traumatic brain injury risk than linear acceleration. To illustrate the difference between radial and oblique impacts, perpendicular impacts through the center of gravity of the head and 45o oblique impacts were simulated. It is obvious that substantially higher strain levels in the brain are obtained for an oblique impact, compared to a corresponding perpendicular one, when impacted into the same padding using an identical impact velocity. It was also clearly illustrated that the radial impact causes substantially higher stresses in the skull with an associated higher risk of skull fractures, and traumatic brain injuries secondary to those.

  2. VELOCIRAPTOR: An X-band photoinjector and linear accelerator for the production of Mono-Energetic {gamma}-rays

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, S.G., E-mail: anderson131@llnl.gov [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94551 (United States); Albert, F.; Bayramian, A.J.; Beer, G.; Bonanno, R.E.; Cross, R.R.; Deis, G.; Ebbers, C.A.; Gibson, D.J.; Hartemann, F.V.; Houck, T.L.; Marsh, R.A.; McNabb, D.P.; Messerly, M.J.; Scarpetti, R.D.; Shverdin, M.Y.; Siders, C.W.; Wu, S.S.; Barty, C.P.J. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94551 (United States); Adolphsen, C.E. [SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, CA 94025 (United States); and others

    2011-11-21

    The rf photoinjector and linear accelerator in the Mono-Energetic Gamma-ray (MEGa-ray) facility at LLNL is presented. This machine uses 11.4 GHz rf technology to accelerate a high-brightness electron beam up to 250 MeV to produce MeV {gamma}-rays through Compton scattering with a Joule-class laser pulse. Compton scattering-based generation of high flux, narrow bandwidth {gamma}-rays places stringent requirements on the performance of the accelerator. The component parts of the accelerator are presented and their requirements described. Simulations of expected electron beam parameters and the resulting light source properties are presented.

  3. 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

  4. 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

  5. Microfluidic technologies for accelerating the clinical translation of nanoparticles

    Science.gov (United States)

    Valencia, Pedro M.; Farokhzad, Omid C.; Karnik, Rohit; Langer, Robert

    2012-10-01

    Using nanoparticles for therapy and imaging holds tremendous promise for the treatment of major diseases such as cancer. However, their translation into the clinic has been slow because it remains difficult to produce nanoparticles that are consistent 'batch-to-batch', and in sufficient quantities for clinical research. Moreover, platforms for rapid screening of nanoparticles are still lacking. Recent microfluidic technologies can tackle some of these issues, and offer a way to accelerate the clinical translation of nanoparticles. In this Progress Article, we highlight the advances in microfluidic systems that can synthesize libraries of nanoparticles in a well-controlled, reproducible and high-throughput manner. We also discuss the use of microfluidics for rapidly evaluating nanoparticles in vitro under microenvironments that mimic the in vivo conditions. Furthermore, we highlight some systems that can manipulate small organisms, which could be used for evaluating the in vivo toxicity of nanoparticles or for drug screening. We conclude with a critical assessment of the near- and long-term impact of microfluidics in the field of nanomedicine.

  6. 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

  7. Manual Linear Movements to Assess Spasticity in a Clinical Setting

    Science.gov (United States)

    Marinelli, Lucio; Trompetto, Carlo; Mori, Laura; Vigo, Gabriele; Traverso, Elisabetta; Colombano, Federica; Abbruzzese, Giovanni

    2013-01-01

    In a clinical setting, where motor-driven systems are not readily available, the major difficulty in the assessment of the stretch reflex lies in the control of passive limb displacement velocity. A potential approach to this problem arises from the use of manual sinusoidal movements (made by continuous alternating flexions and extensions) paced by an external stimulus. Unfortunately, there are conditions in which sinusoidal movements induce interfering phenomena such as the shortening reaction or postactivation depression. In the present paper, a novel manual method to control the velocity of passive linear movements is described and the results obtained from both healthy subjects and spastic patients are reported. This method is based on the synchronisation of movements with tones played by a metronome at different speeds. In a first set of experiments performed in healthy subjects, we demonstrated consistent control of velocity during passive limb movements using this method. Four joints usually examined during muscle tone assessment were tested: wrist, elbow, knee and ankle joints. Following this, we conducted a longitudinal assessment of the stretch reflex amplitude in wrist flexor muscles in patients with spasticity treated with botulinum toxin type A. The evaluators were not only able to vary the movement velocity based on the metronome speed, but also could reproduce the respective speeds two weeks later, despite the changing degree of hypertonia. This method is easy to perform in a clinical setting and hardware requirements are minimal, making it an attractive and robust procedure for the widespread clinical assessment of reflex hypertonia. PMID:23335966

  8. 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)

  9. One Year assessment of shielding for a multi-energy linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Gi; Carlson, Joel; Lee, Hyun Seok; Ye, Sung Joon [Seoul National University Graduate School of Convergence Science and Technology, Seoul (Korea, Republic of); Chung, Jin Beom; Kim, Jae Sung [Dept. of Radiation Oncology, Seoul National University Bundang Hospital, Seoul (Korea, Republic of); Kim, Jung In [Dept. of of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2014-11-15

    In 2005, the publication of Report No. 151 of the National Council on Radiation Protection and Measurements (NCRP) suggested shielding methodologies along with shielding data. Recently, intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) have become more widely used for cancer treatment. Thus, we analyzed shielding parameters for a multi-energy medical linear accelerator using the VMAT technique. Calculated total workload was similar to the recommendation of NCRP Report No. 49 and No. 51. However, these results were higher than the previous results in the NCRP Report No. 151. Also, the VMAT technique uses an intensity modulated beams with various gantry angles so that scattered and leakage doses should be carefully considered by retrospective analysis using the treatment data from each facility.

  10. 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.)

  11. Test Results of a Superconducting Quadrupole Model Designed for Linear Accelerator Applications

    Energy Technology Data Exchange (ETDEWEB)

    Kashikhin, Vladimir S.; Andreev, Nikolai; Chlachidze, Guram; DiMarco, Joseph; Kashikhin, Vadim V.; Lamm, Michael J.; Lopes, Mauricio L.; Orris, Darryl; Tartaglia, Michael; Tompkins, John C.; Velev, Gueorgui; /Fermilab

    2008-08-01

    The first model of a superconducting quadrupole for use in a Linear Accelerator was designed, built and tested at Fermilab. The quadrupole has a 78 mm aperture, and a cold mass length of 680 mm. A superferric magnet configuration with iron poles and four racetrack coils was chosen based on magnet performance, cost, and reliability considerations. Each coil is wound using enamel insulated, 0.5 mm diameter, NbTi superconductor. The quadrupole package also includes racetrack type dipole steering coils. The results of the quadrupole design, manufacturing and test, are presented. Specific issues related to the quadrupole magnetic center stability, superconductor magnetization and mechanical stability are discussed. The magnet quench performance and results of magnetic measurements will also be briefly discussed.

  12. 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

  13. 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

  14. 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.)

  15. 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.)

  16. 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.

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

    DEFF Research Database (Denmark)

    Fränzle, Martin; Herde, Christian

    2003-01-01

    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....... 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...... engine that can be attributed to the richer input language is often amortized by the conciseness gained in the propositional encoding of the BMC problem....

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. Gamma-ray and neutron area monitoring system of linear IFMIF prototype accelerator building

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Hiroki, E-mail: takahashi.hiroki@jaea.go.jp [Japan Atomic Energy Agency (JAEA), Rokkasho, Aomori (Japan); Kojima, Toshiyuki; Narita, Takahiro; Tsutsumi, Kazuyoshi; Maebara, Sunao [Japan Atomic Energy Agency (JAEA), Rokkasho, Aomori (Japan); Sakaki, Hironao [JAEA, Kizugawa, Kyoto (Japan); Nishiyama, Koichi [IFMIF/EVEDA Project Team, Rokkasho, Aomori (Japan)

    2013-10-15

    Highlights: • Area monitoring system and control system are needed for LIPAc radiation management. • To secure the radiation safety, these systems are linked with two kinds of data path. • Hardwired data paths are adopted to realize the fast transfer of interlock signals. • Dual LAN and shared memory are adopted to the reliable transfer of monitoring data. • Data transfers without unnecessary load are designed and configured for these systems. -- Abstract: The linear IFMIF prototype accelerator (LIPAc) produces deuteron beam with 1 MW power. Since huge number of neutrons occur from such a high power beam, therefore, it is important for the radiation management to design a high reliability area monitoring system for gamma-rays and neutrons. To obtain the valuable operation data of the high-power deuteron beam at LIPAc, it is important to link and record the beam operation data and the area monitoring data. We realize the reliable data transfer to provide the area monitoring data to the accelerator control system which needs a high reliability using the shared-memory data link method. This paper describes the area monitoring system in the LIPAc building and the data-link between this system and the LIPAc control system.

  4. 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.

  5. 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.)

  6. 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)

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. SU-E-T-190: First Integration of Steriotactic Radiotherapy Planning System Iplan with Elekta Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Biplab, S; Soumya, R; Paul, S; Jassal, K; Munshi, A; Giri, U; Kumar, V; Roy, S; Ganesh, T; Mohanti, B

    2014-06-01

    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.

  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. 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

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. 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.

  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...

  1. Analytic characterization of linear accelerator radiosurgery dose distributions for fast optimization

    Science.gov (United States)

    Meeks, Sanford L.; Bova, Frank J.; Buatti, John M.; Friedman, William A.; Eyster, Brian; Kendrick, Lance A.

    1999-11-01

    Linear accelerator (linac) radiosurgery utilizes non-coplanar arc therapy delivered through circular collimators. Generally, spherically symmetric arc sets are used, resulting in nominally spherical dose distributions. Various treatment planning parameters may be manipulated to provide dose conformation to irregular lesions. Iterative manipulation of these variables can be a difficult and time-consuming task, because (a) understanding the effect of these parameters is complicated and (b) three-dimensional (3D) dose calculations are computationally expensive. This manipulation can be simplified, however, because the prescription isodose surface for all single isocentre distributions can be approximated by conic sections. In this study, the effects of treatment planning parameter manipulation on the dimensions of the treatment isodose surface were determined empirically. These dimensions were then fitted to analytic functions, assuming that the dose distributions were characterized as conic sections. These analytic functions allowed real-time approximation of the 3D isodose surface. Iterative plan optimization, either manual or automated, is achieved more efficiently using this real time approximation of the dose matrix. Subsequent to iterative plan optimization, the analytic function is related back to the appropriate plan parameters, and the dose distribution is determined using conventional dosimetry calculations. This provides a pseudo-inverse approach to radiosurgery optimization, based solely on geometric considerations.

  2. Response curves of SMT phototransistors used as detectors in megavoltage photon beams from a linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jonas O. da [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear]|[Centro Regional de Ciencias Nucleares (CRCN/CNEN- PE), Recife, PE (Brazil). Lab. de Instrumentacao Nuclear], E-mail: jonassilva@ufpe.br; Antonio Filho, Joao [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear; Santos, Luiz A.P. [Centro Regional de Ciencias Nucleares (CRCN/CNEN- PE), Recife, PE (Brazil). Lab. de Instrumentacao Nuclear; Santos, Walter M. [Hospital Governador Joao Alves Filho, Aracaju, SE (Brazil)

    2007-07-01

    Commercial phototransistors have been successfully used as detectors for low energy X-rays. However, when they are used in high energy X-ray beams, there is a certain loss of sensitivity to the ionizing radiation. This damage is cumulative and irreversible. There are some things that yield variations in the phototransistor response when it is under high energy radiation such as its fabrication technology and its electrical characteristics. The aim of this work is to present experimental results that can be used to correlate the response curve of Surface-Mount Technology (SMT) phototransistors with the loss of sensitivity after irradiation from Linac megavoltage beams. An electrometer was calibrated with a 6430 Keithley{sup R} sub-femto-amperemeter and used to obtain measurements in real-time during the irradiation. The radiation beams were generated by a 6 MV Siemens-Primus linear accelerator at the Hospital Governador Joao Alves Filho, Aracaju. Studies are underway to determine how such behaviour can provide information for treating superficial tumours (radiotherapy) and dosimetric planning in stereotactic radiosurgery. (author)

  3. Analytical calculation of central-axis dosimetric data for a dedicated 6-MV radiosurgery linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Yang, James N.; Pino, Ramiro [Department of Radiation Physics, Unit 94, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030 (United States); Department of Radiology, Baylor College of Medicine and Methodist Hospital, Houston, Texas 77030 (United States)

    2008-10-15

    Narrow beams are extensively used in stereotactic radiosurgery. The accuracy of treatment planning dose calculation depends largely on how well the dosimetric data are measured during the machine commissioning. Narrow beams are characterized by the lack of lateral electronic equilibrium. The lateral electronic disequilibrium in the radiation field and detector's finite size are likely to compromise the accuracy in dose measurements in these beams. This may have a profound impact on outcome in patients who undergo stereotactic radiosurgery. To confirm the measured commissioning data for a dedicated 6-MV linear accelerator-based radiosurgery system, we developed an analytical model to calculate the narrow photon beam central-axis dose. This model is an extension of a previously reported method of Nizin and Mooij for the calculation of the absorbed dose under lateral electronic disequilibrium conditions at depth of d{sub max} or greater. The scatter factor and tissue-maximum ratio were calculated for narrow beams using the parametrized model and compared to carefully measured results for the same beams. For narrow beam radii ranging from 0.2 to 1.5 cm, the differences between the analytical and measured scatter factors were no greater than 1.4%. In addition, the differences between the analytical and measured tissue-maximum ratios were within 3.3% for regions greater than the maximum dose depth. The estimated error of this analytical calculation was less than 2%, which is sufficient to validate measurement results.

  4. 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...

  5. Development Of A Four Cavity Second-harmonic Gyroklystron As Driver For A Linear Accelerator

    CERN Document Server

    Gouveia, E S

    2004-01-01

    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 (α) 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 (&a...

  6. Production Of Intense, Tunable, Quasi-monochromatic X- Rays Using The Rpi Linear Accelerator

    CERN Document Server

    Sones, B A

    2004-01-01

    This research investigated the production of parametric X-rays (PXR) using the 60-MeV electron linear accelerator at Rensselaer Polytechnic Institute. PXR is an intense, energy tunable, and polarized X-ray source derived from the interaction of relativistic electrons and the periodic structure of crystal materials. In this work, PXR photon yields and the associated bremsstrahlung background were characterized for graphite, LiF, Si, Ge, Cu, and W target crystals. A model that considers the experimental geometry and crystal mosaicity was employed to predict PXR energy broadening. Measured energy linewidths consistently agreed with predicted values except in cases using poor quality graphite in which the mosaicity was greater than the PXR characteristic angle, 8.5 mrad for 60 MeV electrons. When the predicted energy linewidth was more narrow than our Si X-ray detector resolution, a near-absorption edge transmission technique was used to measure the PXR energy linewidth for Si(400) FWHM of 134 eV at 9.0 keV (2%) ...

  7. Photoneutron contamination from an 18 MV Saturne medical linear accelerator in the treatment room

    International Nuclear Information System (INIS)

    Dose escalation with high-energy X rays of medical linear accelerators (linacs) in radiotherapy offers several distinct advantages over the lower energy photons. However, owing to photoneutron reactions, interaction of high-energy photons (>8 MV) with various high-Z nuclei of the materials in the linac head components produces unavoidable neutrons. The aim of this study was to evaluate the photoneutron dose equivalent per unit therapeutic X-ray dose of 18 MV, GE Saturne 20 linac in the treatment room using Monte Carlo (MC) MCNP linac head full simulation as well as thermoluminescence dosemeter measurements. This machine is one of the old linac models manufactured by General Electric Company; however, it is widely used in the developing countries because of low cost and simple maintenance for radiotherapy applications. The results showed a significant photoneutron dose from Saturne 20 linac head components especially at distances near the linac head (<150 cm). Results of this work could be used in several applications, especially designing bunker and entrance door shielding against neutrons produced by photoneutron reactions in GE Saturne 20. However, a detailed cost optimisation for a specific room would require a dedicated calculation. (authors)

  8. Control system for linear induction accelerator LIA-2: the structure and hardware

    International Nuclear Information System (INIS)

    The Power Linear Induction Accelerator (LIA) for flash radiography is commissioned in the Budker Institute of Nuclear Physics (BINP) in Novosibirsk. It is a facility producing pulsed electron beam with energy 2 MeV, current 1 kA and spot size less than 2 mm. Beam quality and reliability are required for radiography experiments. The control system of LIA is functionally divided into four subsystems: pulsed power control subsystem, timing subsystem, waveform recording subsystem and interlock subsystem. Features and structure of distributed control system ensuring these demands are discussed. Control system hardware based on CompactPCI and PMC standards is embedded directly into power pulsed generators. CAN-BUS and Ethernet are used as interconnection protocols. Parameters and essential details for measuring equipment and control electronics produced in BINP and available COTS are presented. LIA was tested at single pulse regime of operation and a diameter of the electron beam less than 1.3 mm was achieved. High reliability of the hardware was demonstrated in an environment of high-voltage discharges

  9. Determining optimization of the initial parameters in Monte Carlo simulation for linear accelerator radiotherapy

    Science.gov (United States)

    Chang, Kwo-Ping; Wang, Zhi-Wei; Shiau, An-Cheng

    2014-02-01

    Monte Carlo (MC) method is a well known calculation algorithm which can accurately assess the dose distribution for radiotherapy. The present study investigated all the possible regions of the depth-dose or lateral profiles which may affect the fitting of the initial parameters (mean energy and the radial intensity (full width at half maximum, FWHM) of the incident electron). EGSnrc-based BEAMnrc codes were used to generate the phase space files (SSD=100 cm, FS=40×40 cm2) for the linac (linear accelerator, Varian 21EX, 6 MV photon mode) and EGSnrc-based DOSXYZnrc code was used to calculate the dose in the region of interest. Interpolation of depth dose curves of pre-set energies was proposed as a preliminary step for optimal energy fit. A good approach for determination of the optimal mean energy is the difference comparison of the PDD curves excluding buildup region, and using D(10) as a normalization method. For FWHM fitting, due to electron disequilibrium and the larger statistical uncertainty, using horn or/and penumbra regions will give inconsistent outcomes at various depths. Difference comparisons should be performed in the flat regions of the off-axis dose profiles at various depths to optimize the FWHM parameter.

  10. Nonlinear combination parametric resonance of axially accelerating viscoelastic strings constituted by the standard linear solid model

    Institute of Scientific and Technical Information of China (English)

    LIM; C.W.

    2010-01-01

    Nonlinear combination parametric resonance is investigated for an axially accelerating viscoelastic string.The governing equation of in-planar motion of the string is established by introducing a coordinate transform in the Eulerian equation of a string with moving boundaries.The string under investigation is constituted by the standard linear solid model in which the material,not partial,time derivative was used.The governing equation leads to the Mote model for transverse vibration by omitting the longitudinal component and higher order terms.The Kirchhoff model is derived from the Mote model by replacing the tension with the averaged tension over the string.The two models are respectively analyzed via the method of multiple scales for principal parametric resonance.The amplitudes and the existence conditions of steady-state response and its stability can be numerically determined.Numerical calculations demonstrate the effects of the string material parameters,the initial tension,and the axial speed fluctuation amplitude.The outcomes of the two models are qualitatively and quantitatively compared.

  11. Total skin electron therapy at two energies on a linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Turner, J.R.; Wymme, C.J. [Christchurch Hospital (New Zealand); Hugtenburg, R.P. [Canterbury Univ., Christchurch (New Zealand). Dept. of Physics

    1995-12-01

    Extensive measurements have been performed on the Varian 2100c linear accelerator with a water equivalent phantom, cylindrical phantoms and an anthropomorphic phantom to validate the 12 beam technique and to measure calibration factors with respect to total skin electron therapy (TEST) for the treatment of Mycosis Fungoides. The technique was developed at 2.5 MeV and 3.5 MeV (mean energy at the surface) with the energy degrading screen at 30 cm from the patient. Field flatness over the treatment area was within {+-} 3% with no significant regional variation of energy. The bremstrahlung contamination was 0.06 - 1.2 %. The absolute calibration of absorbed dose to the patient required the measurement of the ratio skin dose to calibration point dose, this was confirmed by measurements with a parallel plate ionization chamber and thermoluminescence dosimetry. The results indicate the care that must be taken with ionization chamber measurements under TSET condition to avoid erroneous readings due to the `polarity effect`. A protocol is suggested for the practical implementation and quality assurance of the technique. The results of two successful treatments are presented and compared with the predicted results from phantoms. 18 refs., 2 tabs., 10 figs.

  12. Study of Compton scattering X-rays production on a linear electron accelerator

    International Nuclear Information System (INIS)

    Compton scattering by collisions between relativistic electron beam and laser beam is a way to produce X-rays. Laser beam is seen as an undulator which gives electrons a periodic waved motion. This radiation emitted by electrons motion has some characteristics close to those of synchrotron radiation but can be produced by smaller machines. ELSA facility at CEA DAM DIF is a linear electron accelerator (17 MeV) running with a photo-injector and a laser (532 nm). Characteristics of electrons and laser beam are favourable to a Compton scattering X-rays experiment. Small interaction probability and small beam sizes (≤ 100 μm, 30 ps (LTMH)) require a careful optimization of spatial and temporal pulses covering. An aluminium bevel-edge allows visualizing beams with CCD and streak cameras. Imaging plates are used as ≤ 11 keV X-rays detectors. These detectors are very sensitive to low signal-to-noise ratio at low energy and give the beam profile. The imaging plates were coupled with a photomultiplier to manage the yield in real time. Experimental results are confirmed by simulations. (author)

  13. Occupational doses due to photoneutrons in medical linear accelerators rooms; Doses ocupacionais devido a neutrons em salas de aceleradores lineares de uso medico

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Alessandro Facure Neves de Salles

    2006-04-15

    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 {mu} Sv/Gy{sub RX}, 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)

  14. Commissioning of a linear accelerator to execute volumetric modulated arc therapy; Comissionamento de um acelerador linear para realizacao da radioterapia em arco modulada volumetricamente

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Leandro R.; Santos, Gabriela R.; Menegussi, Gisela; Silva, Marco A.; Passaro, Anderson M.; Rodrigues, Laura N., E-mail: leandrorg11@hotmail.com [Instituto do Cancer do Estado de Sao Paulo (ICESP), Sao Paulo, SP (Brazil)

    2013-08-15

    Radiotherapy techniques like VMAT allow complex dose distributions modulating the beam intensity within the irradiation field from the handling of multi-blade collimators, variations in dose rate, different speeds of rotation of the gantry and collimator angle allowing greater conformation of the dose to the tumor volume and a lower dose to healthy tissues. To ensure proper dose delivery, the linear particle accelerator must be able to monitor and perform all the variation in these parameters simultaneously. In this work dosimetric tests obtained in the literature that aims to commission, implement and ensure the quality of VMAT treatments were performed performed in the Institute of Cancer of Sao Paulo State (ICESP). From the results obtained it was established a program of quality control for the linear accelerator studied. The linearity and stability response of ionization chamber monitoring, leafs accuracy positioning, flatness and symmetry of beam to VMAT irradiations were evaluated. The obtained results are in agreement with the literature. It can be concluded that the accelerator studied is able to satisfactorily control the variation of all necessary parameters to perform the VMAT treatments. (author)

  15. Radio to $\\gamma$-Ray Emission from Shell-type Supernova Remnants Predictions from Non-linear Shock Acceleration Models

    CERN Document Server

    Baring, M G; Reynolds, S P; Grenier, I; Goret, P; Baring, Matthew G.; Ellison, Donald C.; Reynolds, Stephen P; Grenier, Isabelle; Goret, Philippe

    1999-01-01

    Supernova remnants (SNRs) are widely believed to be the principal source of galactic cosmic rays. Such energetic particles can produce gamma-rays and lower energy photons via interactions with the ambient plasma. In this paper, we present results from a Monte Carlo simulation of non-linear shock structure and acceleration coupled with photon emission in shell-like SNRs. These non-linearities are a by-product of the dynamical influence of the accelerated cosmic rays on the shocked plasma and result in distributions of cosmic rays which deviate from pure power-laws. Such deviations are crucial to acceleration efficiency and spectral considerations, producing GeV/TeV intensity ratios that are quite different from test particle predictions. The Sedov scaling solution for SNR expansions is used to estimate important shock parameters for input into the Monte Carlo simulation. We calculate ion and electron distributions that spawn neutral pion decay, bremsstrahlung, inverse Compton, and synchrotron emission, yieldin...

  16. A dose homogeneity and conformity evaluation between ViewRay and pinnacle-based linear accelerator IMRT treatment plans.

    Science.gov (United States)

    Saenz, Daniel L; Paliwal, Bhudatt R; Bayouth, John E

    2014-04-01

    ViewRay, a novel technology providing soft-tissue imaging during radiotherapy is investigated for treatment planning capabilities assessing treatment plan dose homogeneity and conformity compared with linear accelerator plans. ViewRay offers both adaptive radiotherapy and image guidance. The combination of cobalt-60 (Co-60) with 0.35 Tesla magnetic resonance imaging (MRI) allows for magnetic resonance (MR)-guided intensity-modulated radiation therapy (IMRT) delivery with multiple beams. This study investigated head and neck, lung, and prostate treatment plans to understand what is possible on ViewRay to narrow focus toward sites with optimal dosimetry. The goal is not to provide a rigorous assessment of planning capabilities, but rather a first order demonstration of ViewRay planning abilities. Images, structure sets, points, and dose from treatment plans created in Pinnacle for patients in our clinic were imported into ViewRay. The same objectives were used to assess plan quality and all critical structures were treated as similarly as possible. Homogeneity index (HI), conformity index (CI), and volume receiving conformity increase for lung. The volume receiving 20% of the prescription dose increased 2-8% for head and neck and up to 4% for lung and prostate. Overall, for head and neck Co-60 ViewRay treatments planned with its Monte Carlo treatment planning software were comparable with 6 MV plans computed with convolution superposition algorithm on Pinnacle treatment planning system.

  17. Dosimetric characterization of the 18-MV photon beam from the Siemens Mevatron 77 linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Palta, J.R.; Meyer, J.A.; Hogstrom, K.R.

    1984-09-01

    A comprehensive set of dosimetric measurements has been made on the Mevatron 77.80.67 18-MV photon beam. Percentage depth dose, dose in the buildup region, field size dependence of output, transmission through lead, tray attenuation, and isodose curves for the open and wedged fields were measured using an ionization chamber in water and polystyrene phantoms. These dosimetric measurements sufficiently characterized the beam to permit clinical use. The depth dose at 10-cm depth for a 10 x 10 cm/sup 2/ field at 100-cm source-to-skin distance (SSD) is 80.9%, which meets design specifications. Central axis depth-dose data were fitted to within 0.5% by a set of polynomial equations utilizing a two-dimensional linear regression analysis. Tissue--maximum ratios calculated from depth-dose data agree with measured data to within 2%. Output differences as large as 2.5% were measured for rectangular fields depending on which collimator jaws defined the long dimension of the field. The field size dependence of output was fit to within +- 0.1% by a linear regression. The half-value thickness of the beam was measured to be 13 mm of lead.

  18. Assessment of the setup dependence of detector response functions for mega-voltage linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Fox, Christopher; Simon, Tom; Simon, Bill; Dempsey, James F.; Kahler, Darren; Palta, Jatinder R.; Liu Chihray; Yan Guanghua [Sun Nuclear Inc., 425-A Pineda Court, Melbourne, Florida 32940 and Department of Radiation Oncology, University of Florida, P.O. Box 100385, Gainesville, Florida 32610-0385 (United States); NRE, 202 Nuclear Science Building, University of Florida, P.O. Box 118300, Gainesville, Florida 32611-8300 and Sun Nuclear Inc., 425-A Pineda Court, Melbourne, Florida 32940 (United States); Sun Nuclear Inc., 425-A Pineda Court, Melbourne, Florida 32940 (United States); ViewRay Inc., 2 Thermo Fisher Way, Oakwood Village, Ohio 44146 (United States); Department of Radiation Oncology, University of Florida, P.O. Box 100385, Gainesville, Florida 32610-0385 (United States)

    2010-02-15

    Purpose: Accurate modeling of beam profiles is important for precise treatment planning dosimetry. Calculated beam profiles need to precisely replicate profiles measured during machine commissioning. Finite detector size introduces perturbations into the measured profiles, which, in turn, impact the resulting modeled profiles. The authors investigate a method for extracting the unperturbed beam profiles from those measured during linear accelerator commissioning. Methods: In-plane and cross-plane data were collected for an Elekta Synergy linac at 6 MV using ionization chambers of volume 0.01, 0.04, 0.13, and 0.65 cm{sup 3} and a diode of surface area 0.64 mm{sup 2}. The detectors were orientated with the stem perpendicular to the beam and pointing away from the gantry. Profiles were measured for a 10x10 cm{sup 2} field at depths ranging from 0.8 to 25.0 cm and SSDs from 90 to 110 cm. Shaping parameters of a Gaussian response function were obtained relative to the Edge detector. The Gaussian function was deconvolved from the measured ionization chamber data. The Edge detector profile was taken as an approximation to the true profile, to which deconvolved data were compared. Data were also collected with CC13 and Edge detectors for additional fields and energies on an Elekta Synergy, Varian Trilogy, and Siemens Oncor linear accelerator and response functions obtained. Response functions were compared as a function of depth, SSD, and detector scan direction. Variations in the shaping parameter were introduced and the effect on the resulting deconvolution profiles assessed. Results: Up to 10% setup dependence in the Gaussian shaping parameter occurred, for each detector for a particular plane. This translated to less than a {+-}0.7 mm variation in the 80%-20% penumbral width. For large volume ionization chambers such as the FC65 Farmer type, where the cavity length to diameter ratio is far from 1, the scan direction produced up to a 40% difference in the shaping

  19. Assessment of the setup dependence of detector response functions for mega-voltage linear accelerators

    International Nuclear Information System (INIS)

    Purpose: Accurate modeling of beam profiles is important for precise treatment planning dosimetry. Calculated beam profiles need to precisely replicate profiles measured during machine commissioning. Finite detector size introduces perturbations into the measured profiles, which, in turn, impact the resulting modeled profiles. The authors investigate a method for extracting the unperturbed beam profiles from those measured during linear accelerator commissioning. Methods: In-plane and cross-plane data were collected for an Elekta Synergy linac at 6 MV using ionization chambers of volume 0.01, 0.04, 0.13, and 0.65 cm3 and a diode of surface area 0.64 mm2. The detectors were orientated with the stem perpendicular to the beam and pointing away from the gantry. Profiles were measured for a 10x10 cm2 field at depths ranging from 0.8 to 25.0 cm and SSDs from 90 to 110 cm. Shaping parameters of a Gaussian response function were obtained relative to the Edge detector. The Gaussian function was deconvolved from the measured ionization chamber data. The Edge detector profile was taken as an approximation to the true profile, to which deconvolved data were compared. Data were also collected with CC13 and Edge detectors for additional fields and energies on an Elekta Synergy, Varian Trilogy, and Siemens Oncor linear accelerator and response functions obtained. Response functions were compared as a function of depth, SSD, and detector scan direction. Variations in the shaping parameter were introduced and the effect on the resulting deconvolution profiles assessed. Results: Up to 10% setup dependence in the Gaussian shaping parameter occurred, for each detector for a particular plane. This translated to less than a ±0.7 mm variation in the 80%-20% penumbral width. For large volume ionization chambers such as the FC65 Farmer type, where the cavity length to diameter ratio is far from 1, the scan direction produced up to a 40% difference in the shaping parameter between in

  20. Linear accelerator-based stereotactic radiosurgery in recurrent glioblastoma: A single center experience

    Directory of Open Access Journals (Sweden)

    Sirin Sait

    2011-01-01

    Full Text Available Background/Aim. Management of patients with recurrent glioblastoma (GB comprises a therapeutic challenge in neurooncology owing to the aggressive nature of the disease with poor local control despite a combined modality treatment. The majority of cases recur within the highdose radiotherapy field limiting the use of conventional techniques for re-irradiation due to potential toxicity. Stereotactic radiosurgery (SRS offers a viable noninvasive therapeutic option in palliative treatment of recurrent GB as a sophisticated modality with improved setup accuracy allowing the administration of high-dose, precise radiotherapy. The aim of the study was to, we report our experience with single-dose linear accelerator (LINAC based SRS in the management of patients with recurrent GB. Methods. Between 1998 and 2010 a total of 19 patients with recurrent GB were treated using single-dose LINAC-based SRS. The median age was 47 (23-65 years at primary diagnosis. Karnofsky Performance Score was ≥ 70 for all the patients. The median planning target volume (PTV was 13 (7-19 cc. The median marginal dose was 16 (10-19 Gy prescribed to the 80%-95% isodose line encompassing the planning target volume. The median follow-up time was 13 (2-59 months. Results. The median survival was 21 months and 9.3 months from the initial GB diagnosis and from SRS, respectively. The median progression-free survival from SRS was 5.7 months. All the patients tolerated radiosurgical treatment well without any Common Toxicity Criteria (CTC grade > 2 acute side effects. Conclusion. Single-dose LINAC-based SRS is a safe and well- tolerated palliative therapeutic option in the management of patients with recurrent GB.

  1. Application of Failure Mode and Effects Analysis to Intraoperative Radiation Therapy Using Mobile Electron Linear Accelerators

    International Nuclear Information System (INIS)

    Purpose: Failure mode and effects analysis (FMEA) represents a prospective approach for risk assessment. A multidisciplinary working group of the Italian Association for Medical Physics applied FMEA to electron beam intraoperative radiation therapy (IORT) delivered using mobile linear accelerators, aiming at preventing accidental exposures to the patient. Methods and Materials: FMEA was applied to the IORT process, for the stages of the treatment delivery and verification, and consisted of three steps: 1) identification of the involved subprocesses; 2) identification and ranking of the potential failure modes, together with their causes and effects, using the risk probability number (RPN) scoring system, based on the product of three parameters (severity, frequency of occurrence and detectability, each ranging from 1 to 10); 3) identification of additional safety measures to be proposed for process quality and safety improvement. RPN upper threshold for little concern of risk was set at 125. Results: Twenty-four subprocesses were identified. Ten potential failure modes were found and scored, in terms of RPN, in the range of 42–216. The most critical failure modes consisted of internal shield misalignment, wrong Monitor Unit calculation and incorrect data entry at treatment console. Potential causes of failure included shield displacement, human errors, such as underestimation of CTV extension, mainly because of lack of adequate training and time pressures, failure in the communication between operators, and machine malfunctioning. The main effects of failure were represented by CTV underdose, wrong dose distribution and/or delivery, unintended normal tissue irradiation. As additional safety measures, the utilization of a dedicated staff for IORT, double-checking of MU calculation and data entry and finally implementation of in vivo dosimetry were suggested. Conclusions: FMEA appeared as a useful tool for prospective evaluation of patient safety in radiotherapy

  2. A collimated detection system for assessing leakage dose from medical linear accelerators at the patient plane.

    Science.gov (United States)

    Lonski, P; Taylor, M L; Franich, R D; Kron, T

    2014-03-01

    Leakage radiation from linear accelerators can make a significant contribution to healthy tissue dose in patients undergoing radiotherapy. In this work thermoluminescent dosimeters (LiF:Mg,Cu,P TLD chips) were used in a focused lead cone loaded with TLD chips for the purpose of evaluating leakage dose at the patient plane. By placing the TLDs at one end of a stereotactic cone, a focused measurement device is created; this was tested both in and out of the primary beam of a Varian 21-iX linac using 6 MV photons. Acrylic build up material of 1.2 cm thickness was used inside the cone and measurements made with either one or three TLD chips at a given distance from the target. Comparing the readings of three dosimeters in one plane inside the cone offered information regarding the orientation of the cone relative to a radiation source. Measurements in the patient plane with the linac gantry at various angles demonstrated that leakage dose was approximately 0.01% of the primary beam out of field when the cone was pointed directly towards the target and 0.0025% elsewhere (due to scatter within the gantry). No specific 'hot spots' (e.g., insufficient shielding or gaps at abutments) were observed. Focused cone measurements facilitate leakage dose measurements from the linac head directly at the patient plane and allow one to infer the fraction of leakage due to 'direct' photons (along the ray-path from the bremsstrahlung target) and that due to scattered photons.

  3. Treatment vault shielding for a flattening filter-free medical linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Kry, Stephen F; Howell, Rebecca M; Polf, Jerimy; Mohan, Radhe; Vassiliev, Oleg N [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)], E-mail: sfkry@mdanderson.org

    2009-03-07

    The requirements for shielding a treatment vault with a Varian Clinac 2100 medical linear accelerator operated both with and without the flattening filter were assessed. Basic shielding parameters, such as primary beam tenth-value layers (TVLs), patient scatter fractions, and wall scatter fractions, were calculated using Monte Carlo simulations of 6, 10 and 18 MV beams. Relative integral target current requirements were determined from treatment planning studies of several disease sites with, and without, the flattening filter. The flattened beam shielding data were compared to data published in NCRP Report No. 151, and the unflattened beam shielding data were presented relative to the NCRP data. Finally, the shielding requirements for a typical treatment vault were determined for a single-energy (6 MV) linac and a dual-energy (6 MV/18 MV) linac. With the exception of large-angle patient scatter fractions and wall scatter fractions, the vault shielding parameters were reduced when the flattening filter was removed. Much of this reduction was consistent with the reduced average energy of the FFF beams. Primary beam TVLs were reduced by 12%, on average, and small-angle scatter fractions were reduced by up to 30%. Head leakage was markedly reduced because less integral target current was required to deliver the target dose. For the treatment vault examined in the current study, removal of the flattening filter reduced the required thickness of the primary and secondary barriers by 10-20%, corresponding to 18 m{sup 3} less concrete to shield the single-energy linac and 36 m{sup 3} less concrete to shield the dual-energy linac. Thus, a shielding advantage was found when the linac was operated without the flattening filter. This translates into a reduction in occupational exposure and/or the cost and space of shielding.

  4. Linear Accelerator-Based Radiosurgery Alone for Arteriovenous Malformation: More Than 12 Years of Observation

    Energy Technology Data Exchange (ETDEWEB)

    Matsuo, Takayuki, E-mail: takayuki@nagasaki-u.ac.jp; Kamada, Kensaku; Izumo, Tsuyoshi; Hayashi, Nobuyuki; Nagata, Izumi

    2014-07-01

    Purpose: Although radiosurgery is an accepted treatment method for intracranial arteriovenous malformations (AVMs), its long-term therapeutic effects have not been sufficiently evaluated, and many reports of long-term observations are from gamma-knife facilities. Furthermore, there are few reported results of treatment using only linear accelerator (LINAC)-based radiosurgery (LBRS). Methods and Materials: Over a period of more than 12 years, we followed the long-term results of LBRS treatment performed in 51 AVM patients. Results: The actuarial obliteration rates, after a single radiosurgery session, at 3, 5, 10, and 15 years were 46.9%, 54.0%, 64.4%, and 68.0%, respectively; when subsequent radiosurgeries were included, the rates were 46.9%, 61.3%, 74.2%, and 90.3%, respectively. Obliteration rates were significantly related to target volumes ≥4 cm{sup 3}, marginal doses ≥12 Gy, Spetzler-Martin grades (1 vs other), and AVM scores ≥1.5; multivariate analyses revealed a significant difference for target volumes ≥4 cm{sup 3}. The postprocedural actuarial symptomatic radiation injury rates, after a single radiation surgery session, at 5, 10, and 15 years were 12.3%, 16.8%, and 19.1%, respectively. Volumes ≥4 cm{sup 3}, location (lobular or other), AVM scores ≥1.5, and the number of radiosurgery were related to radiation injury incidence; multivariate analyses revealed significant differences associated with volumes ≥4 cm{sup 3} and location (lobular or other). Conclusions: Positive results can be obtained with LBRS when performed with a target volume ≤4 cm{sup 3}, an AVM score ≤1.5, and ≥12 Gy radiation. Bleeding and radiation injuries may appear even 10 years after treatment, necessitating long-term observation.

  5. VMAT linear accelerator commissioning and quality assurance: dose control and gantry speed tests.

    Science.gov (United States)

    Barnes, Michael P; Rowshanfarzad, Pejman; Greer, Peter B

    2016-01-01

    In VMAT treatment delivery the ability of the linear accelerator (linac) to accurately control dose versus gantry angle is critical to delivering the plan correctly. A new VMAT test delivery was developed to specifically test the dose versus gantry angle with the full range of allowed gantry speeds and dose rates. The gantry-mounted IBA MatriXX with attached inclinometer was used in movie mode to measure the instantaneous relative dose versus gantry angle during the plan every 0.54 s. The results were compared to the expected relative dose at each gantry angle calculated from the plan. The same dataset was also used to compare the instantaneous gan-try speeds throughout the delivery compared to the expected gantry speeds from the plan. Measurements performed across four linacs generally show agreement between measurement and plan to within 1.5% in the constant dose rate regions and dose rate modulation within 0.1 s of the plan. Instantaneous gantry speed was measured to be within 0.11°/s of the plan (1 SD). An error in one linac was detected in that the nominal gantry speed was incorrectly calibrated. This test provides a practical method to quality-assure critical aspects of VMAT delivery including dose versus gantry angle and gantry speed control. The method can be performed with any detector that can acquire time-resolved dosimetric information that can be synchronized with a measurement of gantry angle. The test fulfils several of the aims of the recent Netherlands Commission on Radiation Dosimetry (NCS) Report 24, which provides recommendations for comprehensive VMAT quality assurance. PMID:27167282

  6. Small field detector correction factors: effects of the flattening filter for Elekta and Varian linear accelerators.

    Science.gov (United States)

    Tyler, Madelaine K; Liu, Paul Z Y; Lee, Christopher; McKenzie, David R; Suchowerska, Natalka

    2016-01-01

    Flattening filter-free (FFF) beams are becoming the preferred beam type for stereotactic radiosurgery (SRS) and stereotactic ablative radiation therapy (SABR), as they enable an increase in dose rate and a decrease in treatment time. This work assesses the effects of the flattening filter on small field output factors for 6 MV beams generated by both Elekta and Varian linear accelerators, and determines differences between detector response in flattened (FF) and FFF beams. Relative output factors were measured with a range of detectors (diodes, ionization cham-bers, radiochromic film, and microDiamond) and referenced to the relative output factors measured with an air core fiber optic dosimeter (FOD), a scintillation dosimeter developed at Chris O'Brien Lifehouse, Sydney. Small field correction factors were generated for both FF and FFF beams. Diode measured detector response was compared with a recently published mathematical relation to predict diode response corrections in small fields. The effect of flattening filter removal on detector response was quantified using a ratio of relative detector responses in FFF and FF fields for the same field size. The removal of the flattening filter was found to have a small but measurable effect on ionization chamber response with maximum deviations of less than ± 0.9% across all field sizes measured. Solid-state detectors showed an increased dependence on the flattening filter of up to ± 1.6%. Measured diode response was within ± 1.1% of the published mathematical relation for all fields up to 30 mm, independent of linac type and presence or absence of a flattening filter. For 6 MV beams, detector correction factors between FFF and FF beams are interchangeable for a linac between FF and FFF modes, providing that an additional uncertainty of up to ± 1.6% is accepted. PMID:27167280

  7. Screening Approach to the Activation of Soil and Contamination of Groundwater at Linear Proton Accelerator Sites

    CERN Document Server

    Otto, Thomas

    The activation of soil and the contamination of groundwater at proton accelerator sites with the radionuclides 3H and 22Na are estimated with a Monte-Carlo calculation and a conservative soil- and ground water model. The obtained radionuclide concentrations show that the underground environment of future accelerators must be adequately protected against a migration of activation products. This study is of particular importance for the proton driver accelerator in the planned EURISOL facility.

  8. Do technological advances in linear accelerators improve dosimetric outcomes in stereotaxy? A head-on comparison of seven linear accelerators using volumetric modulated arc therapy-based stereotactic planning

    OpenAIRE

    Sarkar, B.; Pradhan, A.; A Munshi

    2016-01-01

    Introduction: Linear accelerator (Linac) based stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT) using volumetric modulated arc therapy (VMAT) has been used for treating small intracranial lesions. Recent development in the Linacs such as inbuilt micro multileaf collimator (MLC) and flattening filter free (FFF) beam are intended to provide a better dose conformity and faster delivery when using VMAT technique. This study was aimed to compare the dosimetric outcomes and monit...

  9. Linear induction accelerator for charge-neutralized ion beams in inertial confinement fusion

    Energy Technology Data Exchange (ETDEWEB)

    Batishchev, O.V.; Golota, V.I.; Karas, V.I.; Kiyashko, V.A.; Kornilov, E.A.; Sigov, Yu.S.; Silaev, I.I.; Fainberg, Ya.B. [Khar`kov Physico-Technical Institute (Russian Federation)

    1993-05-01

    Results are presented from experimental, analytical, and numerical studies of the physical processes that occur in a high-current ion induction accelerator (the ion linac IINDUS). The experiments were performed in a module of the IINDUS accelerator consisting of an injector of gaseous or metallic ions and two induction sections with magnetically insulated cusps in the accelerator gaps filled with plasma. The following ion beam parameters were found: 2-3 kA, 0.5 MeV, 0.5 {mu}s. The two most dangerous instabilities effecting beam quality were studied. These are the high-frequency beam-plasma instability and the filamentation instability. A nonlinear analytical theory of charge neutralization of a high-current ion beam in magnetically insulated accelerating gaps is presented. In order to develop diagnostics for high-current beams of accelerated particles the amplitude and shape of the acoustic pulse excited in a metal target by the particles have been studied theoretically and experimentally as functions of the beam parameters. The possibility of practical application of this acceleration in ICF has been studied using a 2.5-dimensional relativistic electromagnetic code to simulate the processes of acceleration, charge neutralization, and stability of the ion beam in the accelerating channel. The results provide evidence in favor of the prospects for this direction of research. 70 refs., 13 figs.

  10. Performance of MBE-4: An experimental multiple beam induction linear accelerator for heavy ions

    International Nuclear Information System (INIS)

    An experimental induction linac, called MBE-4, has been constructed to demonstrate acceleration and current amplification of multiple heavy ion beams. This work is part of a program to study the use of such an accelerator as a driver for heavy ion inertial fusion. MBE-4 is 16m long and accelerates four space-charge-dominated beams of singly-charged cesium ions, in this case from 200 keV to 700 keV, amplifying the current in each beam from 10mA by a factor of nine. Construction of the experiment was completed late in 1987 and we present the results of detailed measurements of the longitudinal beam dynamics. Of particular interest is the contribution of acceleration errors to the growth of current fluctuations and to the longitudinal emittance. The effectiveness of the longitudinal focusing, accomplished by means of the controlled time dependence of the accelerating fields, is also discussed. 4 refs., 5 figs., 1 tab

  11. Accelerator

    International Nuclear Information System (INIS)

    The invention claims equipment for stabilizing the position of the front covers of the accelerator chamber in cyclic accelerators which significantly increases accelerator reliability. For stabilizing, it uses hydraulic cushions placed between the electromagnet pole pieces and the front chamber covers. The top and the bottom cushions are hydraulically connected. The cushions are disconnected and removed from the hydraulic line using valves. (J.P.)

  12. Translational Vestibulo-Ocular Reflex and Motion Perception During Interaural Linear Acceleration: Comparison of Different Motion Paradigms

    Science.gov (United States)

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

    2011-01-01

    The neural mechanisms to resolve ambiguous tilt-translation motion have been hypothesized to be different for motion perception and eye movements. Previous studies have demonstrated differences in ocular and perceptual responses using a variety of motion paradigms, including Off-Vertical Axis Rotation (OVAR), Variable Radius Centrifugation (VRC), translation along a linear track, and tilt about an Earth-horizontal axis. While the linear acceleration across these motion paradigms is presumably equivalent, there are important differences in semicircular canal cues. The purpose of this study was to compare translation motion perception and horizontal slow phase velocity to quantify consistencies, or lack thereof, across four different motion paradigms. Twelve healthy subjects were exposed to sinusoidal interaural linear acceleration between 0.01 and 0.6 Hz at 1.7 m/s/s (equivalent to 10 tilt) using OVAR, VRC, roll tilt, and lateral translation. During each trial, subjects verbally reported the amount of perceived peak-to-peak lateral translation and indicated the direction of motion with a joystick. Binocular eye movements were recorded using video-oculography. In general, the gain of translation perception (ratio of reported linear displacement to equivalent linear stimulus displacement) increased with stimulus frequency, while the phase did not significantly vary. However, translation perception was more pronounced during both VRC and lateral translation involving actual translation, whereas perceptions were less consistent and more variable during OVAR and roll tilt which did not involve actual translation. For each motion paradigm, horizontal eye movements were negligible at low frequencies and showed phase lead relative to the linear stimulus. At higher frequencies, the gain of the eye movements increased and became more inphase with the acceleration stimulus. While these results are consistent with the hypothesis that the neural computational strategies for

  13. The first implementation of respiratory triggered 4DCBCT on a linear accelerator

    Science.gov (United States)

    O'Brien, Ricky T.; Cooper, Benjamin J.; Shieh, Chun-Chien; Stankovic, Uros; Keall, Paul J.; Sonke, Jan-Jakob

    2016-05-01

    signal to noise and contrast to noise ratios. RT-4DCBCT has been experimentally realised and reduced to practice on a linear accelerator with a measurable imaging dose reductions over conventional 4DCBCT and little degradation in image quality.

  14. Retrospective analysis of linear accelerator output constancy checks using process control techniques.

    Science.gov (United States)

    Sanghangthum, Taweap; Suriyapee, Sivalee; Srisatit, Somyot; Pawlicki, Todd

    2013-01-01

    Shewhart control charts have previously been suggested as a process control tool for use in routine linear accelerator (linac) output verifications. However, a comprehensive approach to process control has not been investigated for linac output verifications. The purpose of this work is to investigate a comprehensive process control approach to linac output constancy quality assurance (QA). The RBA-3 dose constancy check was used to verify outputs of photon beams and electron beams delivered by a Varian Clinac 21EX linac. The data were collected during 2009 to 2010. Shewhart-type control charts, exponentially weighted moving average (EWMA) charts, and capability indices were applied to these processes. The Shewhart-type individuals chart (X-chart) was used and the number of data points used to calculate the control limits was varied. The parameters tested for the EWMA charts (smoothing parameter (λ) and the control limit width (L)) were λ = 0.05, L = 2.492; λ = 0.10, L = 2.703; and λ = 0.20, L = 2.860, as well as the number of points used to estimate the initial process mean and variation. Lastly, the number of in-control data points used to determine process capability (C(p)) and acceptability (C(pk)) were investigated, comparing the first in-control run to the longest in-control run of the process data. C(p) and C(pk) values greater than 1.0 were considered acceptable. The 95% confidence intervals were reported. The X-charts detected systematic errors (e.g., device setup errors). In-control run lengths on the X-charts varied from 5 to 30 output measurements (about one to seven months). EWMA charts showed in-control runs ranging from 9 to 33 output measurements (about two to eight months). The C(p) and C(pk) ratios are higher than 1.0 for all energies, except 12 and 20 MeV. However, 10 MV and 6, 9, and 16 MeV were in question when considering the 95% confidence limits. The X-chart should be calculated using 8-12 data points. For EWMA chart, using 4 data points

  15. The Variation of Surface Dose by Beam Spoiler in 10 MV Photon Beam from Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Seong Cheol; Kim, Jun Ho; Lee, Choul Soo [Dept. of Radiation Oncology, Kosin University Gospel Hospital, Busan (Korea, Republic of)

    2006-03-15

    The purpose of this study is to find a optimal beam spoiler condition on the dose distribution near the surface, when treating a squamous cell carcinoma of the head and neck and a lymphatic region with 10 MV photon beam. The use of a optimal spoiler allows delivering high dose to a superficial tumor volume, while maintaining the skin-sparing effect in the area between the surface to the depth of 0.4 cm. The lucite beam spoiler, which were a tissue equivalent, were made and placed between the surface and the photon collimators of linear accelerator. The surface-dose, the dose at the depth of 0.4 cm, and the maximum dose at the dmax were measured with a parallel-plate ionization chamber for 5 x 5 cm to 30 x 30 cm{sup 2} field sizes using lucite spoilers with different thicknesses at varying skin-to-spoiler separation (SSS). In the same condition, the dose was measured with bolus and compared with beam spoiler. The spoiler increased the surface and build-up dose and shifted the depth of maximum dose toward the surface. With a 10 MV x-ray beam and a optimal beam spoiler when treating a patient, a similar build-up dose with a 6 MV photon beam could be achieved, while maintaining a certain amount of skin spring. But it was provided higher surface dose under SSS of less than 5 cm, the spoiler thickness of more than 1.8 cm or more, and larger field size than 20 x 20 cm{sup 2} provided higher surface dose like bolus and obliterated the spin-sparing effect. the effects of the beam spoiler on beam profile was reduced with increasing depths. The lucite spoiler allowed using of a 10 MV photon beam for the radiation treatment of head and neck caner by yielding secondary scattered electron on the surface. The dose at superficial depth was increased and the depth of maximum dose was moved to near the skin surface. Spoiling the 10 MV x-ray beam resulted in treatment plans that maintained dose homogeneity without the consequence of increased skin reaction or treat volume underdose

  16. Commissioning of the Varian TrueBeam linear accelerator: A multi-institutional study

    International Nuclear Information System (INIS)

    Purpose: Latest generation linear accelerators (linacs), i.e., TrueBeam (Varian Medical Systems, Palo Alto, CA) and its stereotactic counterpart, TrueBeam STx, have several unique features, including high-dose-rate flattening-filter-free (FFF) photon modes, reengineered electron modes with new scattering foil geometries, updated imaging hardware/software, and a novel control system. An evaluation of five TrueBeam linacs at three different institutions has been performed and this work reports on the commissioning experience. Methods: Acceptance and commissioning data were analyzed for five TrueBeam linacs equipped with 120 leaf (5 mm width) MLCs at three different institutions. Dosimetric data and mechanical parameters were compared. These included measurements of photon beam profiles (6X, 6XFFF, 10X, 10XFFF, 15X), photon and electron percent depth dose (PDD) curves (6, 9, 12 MeV), relative photon output factors (Scp), electron cone factors, mechanical isocenter accuracy, MLC transmission, and dosimetric leaf gap (DLG). End-to-end testing and IMRT commissioning were also conducted. Results: Gantry/collimator isocentricity measurements were similar (0.27–0.28 mm), with overall couch/gantry/collimator values of 0.46–0.68 mm across the three institutions. Dosimetric data showed good agreement between machines. The average MLC DLGs for 6, 10, and 15 MV photons were 1.33 ± 0.23, 1.57 ± 0.24, and 1.61 ± 0.26 mm, respectively. 6XFFF and 10XFFF modes had average DLGs of 1.16 ± 0.22 and 1.44 ± 0.30 mm, respectively. MLC transmission showed minimal variation across the three institutions, with the standard deviation x varied less than 0.3% for all linacs. Output factors (Scp) and electron cone factors agreed within 0.27%, on average; largest variations were observed for small field sizes (1.2% coefficient of variation, 10 MV, 2 × 2 cm2) and small cone sizes (2 cone), respectively. Conclusions: Overall, excellent agreement was observed in TrueBeam commissioning data

  17. The first implementation of respiratory triggered 4DCBCT on a linear accelerator

    Science.gov (United States)

    O’Brien, Ricky T.; Cooper, Benjamin J.; Shieh, Chun-Chien; Stankovic, Uros; Keall, Paul J.; Sonke, Jan-Jakob

    2016-05-01

    the signal to noise and contrast to noise ratios. RT-4DCBCT has been experimentally realised and reduced to practice on a linear accelerator with a measurable imaging dose reductions over conventional 4DCBCT and little degradation in image quality.

  18. The first implementation of respiratory triggered 4DCBCT on a linear accelerator.

    Science.gov (United States)

    O'Brien, Ricky T; Cooper, Benjamin J; Shieh, Chun-Chien; Stankovic, Uros; Keall, Paul J; Sonke, Jan-Jakob

    2016-05-01

    signal to noise and contrast to noise ratios. RT-4DCBCT has been experimentally realised and reduced to practice on a linear accelerator with a measurable imaging dose reductions over conventional 4DCBCT and little degradation in image quality. PMID:27051977

  19. On isocentre adjustment and quality control in linear accelerator based radiosurgery with circular collimators and room lasers

    Science.gov (United States)

    Treuer, H.; Hoevels, M.; Luyken, K.; Gierich, A.; Kocher, M.; Müller, R.-P.; Sturm, V.

    2000-08-01

    We have developed a densitometric method for measuring the isocentric accuracy and the accuracy of marking the isocentre position for linear accelerator based radiosurgery with circular collimators and room lasers. Isocentric shots are used to determine the accuracy of marking the isocentre position with room lasers and star shots are used to determine the wobble of the gantry and table rotation movement, the effect of gantry sag, the stereotactic collimator alignment, and the minimal distance between gantry and table rotation axes. Since the method is based on densitometric measurements, beam spot stability is implicitly tested. The method developed is also suitable for quality assurance and has proved to be useful in optimizing isocentric accuracy. The method is simple to perform and only requires a film box and film scanner for instrumentation. Thus, the method has the potential to become widely available and may therefore be useful in standardizing the description of linear accelerator based radiosurgical systems.

  20. Efficient modeling of plasma wakefield acceleration in quasi-non-linear-regimes with the hybrid code Architect

    Science.gov (United States)

    Marocchino, A.; Massimo, F.; Rossi, A. R.; Chiadroni, E.; Ferrario, M.

    2016-09-01

    In this paper we present a hybrid approach aiming to assess feasible plasma wakefield acceleration working points with reduced computation resources. The growing interest for plasma wakefield acceleration and especially the need to control with increasing precision the quality of the accelerated bunch demands for more accurate and faster simulations. Particle in cell codes are the state of the art technique to simulate the underlying physics, however the run-time represents the major drawback. Architect is a hybrid code that treats the bunch kinetically and the background electron plasma as a fluid, initialising bunches in vacuum so to take into account for the transition from vacuum to plasma. Architect solves directly the Maxwell's equations on a Yee lattice. Such an approach allows us to drastically reduce run time without loss of generality or accuracy up to the weakly non linear regime.

  1. Implementation of intraoperative radiotherapy in a linear accelerator Varian 21EX; Implementacao da radioterapia intraoperatoria em um acelerador linear VARIAN 21EX

    Energy Technology Data Exchange (ETDEWEB)

    Piriz, Gustavo H.; Lozano, Enrique; Banguero, Yolma; Varon, Carlos Fernando; Mancilla, Claudio S. [Instituto Nacional del Cancer, Santiago (Chile). Radioterapia; Parra, Cristian [Universidad de la Frontera, Temuco (Chile); Pacheco, P. [Universidad Nacional Mayor de San Marcos, Lima (Peru)

    2011-07-01

    The aim of this paper is to present the experience on intraoperative radiotherapy, which has as the reference center the network of radiotherapy in Chile. It is detailed the construction of a system of applicators with an easy coupling on a linear accelerator collimator. It is also detailed the cost and the measurements set up with their corresponding percentage depth dose and isodose curves. This technique was implemented in a Varian Clinac 21EX for beams with 6, 9 and 12 MeV electron energy. The coupling system provides a good dose distribution both laterally and in depth for different energies. This provides a good coverage of treatment planning volume. (author)

  2. Vestibular modulation of muscle sympathetic nerve activity by the utricle during sub-perceptual sinusoidal linear acceleration in humans.

    Science.gov (United States)

    Hammam, Elie; Hau, Chui Luen Vera; Wong, Kwok-Shing; Kwok, Kenny; Macefield, Vaughan G

    2014-04-01

    We assessed the capacity for the vestibular utricle to modulate muscle sympathetic nerve activity (MSNA) during sinusoidal linear acceleration at amplitudes extending from imperceptible to clearly perceptible. Subjects (n = 16) were seated in a sealed room, eliminating visual cues, mounted on a linear motor that could deliver peak sinusoidal accelerations of 30 mG in the antero-posterior direction. Subjects sat on a padded chair with their neck and head supported vertically, thereby minimizing somatosensory cues, facing the direction of motion in the anterior direction. Each block of sinusoidal motion was applied at a time unknown to subjects and in a random order of amplitudes (1.25, 2.5, 5, 10, 20 and 30 mG), at a constant frequency of 0.2 Hz. MSNA was recorded via tungsten microelectrodes inserted into muscle fascicles of the common peroneal nerve. Subjects used a linear potentiometer aligned to the axis of motion to indicate any perceived movement, which was compared with the accelerometer signal of actual room movement. On average, 67% correct detection of movement did not occur until 6.5 mG, with correct knowledge of the direction of movement at ~10 mG. Cross-correlation analysis revealed potent sinusoidal modulation of MSNA even at accelerations subjects could not perceive (1.25-5 mG). The modulation index showed a positive linear increase with acceleration amplitude, such that the modulation was significantly higher (25.3 ± 3.7%) at 30 mG than at 1.25 mG (15.5 ± 1.2%). We conclude that selective activation of the vestibular utricle causes a pronounced modulation of MSNA, even at levels well below perceptual threshold, and provides further evidence in support of the importance of vestibulosympathetic reflexes in human cardiovascular control. PMID:24504198

  3. SU-E-T-384: Experimental Verification of a Monte Carlo Linear Accelerator Model Using a Radiochromic Film Stack Dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    McCaw, T; Culberson, W; DeWerd, L [University of Wisconsin Medical Radiation Research Center, Madison, WI (United States)

    2014-06-01

    Purpose: To experimentally verify a Monte Carlo (MC) linear accelerator model for the simulation of intensity-modulated radiation therapy (IMRT) treatments of moving targets. Methods: A Varian Clinac™ 21EX linear accelerator was modeled using the EGSnrc user code BEAMnrc. The mean energy, radial-intensity distribution, and divergence of the electron beam incident on the bremsstrahlung target were adjusted to achieve agreement between simulated and measured percentage-depth-dose and transverse field profiles for a 6 MV beam. A seven-field step-and-shoot IMRT lung procedure was prepared using Varian Eclipse™ treatment planning software. The plan was delivered using a Clinac™ 21EX linear accelerator and measured with a Gafchromic™ EBT2 film stack dosimeter (FSD) in two separate static geometries: within a cylindrical water-equivalent-plastic phantom and within an anthropomorphic chest phantom. Two measurements were completed in each setup. The dose distribution for each geometry was simulated using the EGSnrc user code DOSXYZnrc. MC geometries of the treatment couch, cylindrical phantom, and chest phantom were developed by thresholding CT data sets using MATLAB™. The FSD was modeled as water. The measured and simulated dose distributions were normalized to the median dose within the FSD. Results: Using an electron beam with a mean energy of 6.05 MeV, a Gaussian radial-intensity distribution with a full width at half maximum of 1.5 mm, and a divergence of 0°, the measured and simulated dose profiles agree within 1.75% and 1 mm. Measured and simulated dose distributions within both the cylindrical and chest phantoms agree within 3% over 94% of the FSD volume. The overall uncertainty in the FSD measurements is 3.1% (k=1). Conclusion: MC simulations agree with FSD measurements within measurement uncertainty, thereby verifying the accuracy of the linear accelerator model for the simulation of IMRT treatments of static geometries. The experimental verification

  4. Critical system issues and modeling requirements - the problem of beam energy sweep in an electron linear induction accelerator

    International Nuclear Information System (INIS)

    In this paper the authors attempt to motivate the development of modeling tools for linear induction accelerator components by giving examples of performance limitations related to energy sweep. The most pressing issues is the development of an accurate model of the switching behavior of large magnetic cores at high dB/dt in the accelerator and magnetic compression modulators. Ideally one would like to have a model with as few parameters as possible that allows the user to choose the core geometry and magnetic material and perhaps a few parameters characterizing the switch model. Beyond this, the critical modeling tasks are: simulation of a magnetic compression modulator, modeling the reset dynamics of a magnetic compression modulator, modeling the loading characteristics of a linear induction accelerator cell, and modeling the electron injector current including the dynamics of feedback modulation and beam loading in an accelerator cell. Of course in the development of these models care should be given to benchmarking them against data from experimental systems. Beyond that one should aim for tools that have predictive power so that they can be used as design tools and not merely to replicate existing data

  5. Advances in X-Band and S-Band Linear Accelerators for Security, NDT, and Other Applications

    CERN Document Server

    Mishin, Andrey V

    2005-01-01

    At AS&E High Energy Systems Division, we designed several new advanced high energy electron beam and X-ray sources. Our primary focus has always been in building the world's most portable commercial X-band accelerators. Today, our X-band systems frequently exceed performance of the similar S-band machines, while they are more portable compared to the latter. The new designs of the X-band accelerators in the most practical energy range from 1 MeV to 6 MeV have been tested delivering outstanding results. Seventy 6 MeV X-band linacs systems have been produced. The most compact linac for security is used by AS&E in a self-shielded, Shaped Energy™ cargo screening system. We pioneered using the X-band linear accelerators for CT, producing high quality images of oil pipes and wood logs. An X-band linear accelerator head on a robotic arm has been used for electron beam radiation curing of an odd-shaped graphite composite part. We developed the broad-range 4 MeV to over 10 MeV energy-regulated X-band ...

  6. Factors Predictive of Symptomatic Radiation Injury After Linear Accelerator-Based Stereotactic Radiosurgery for Intracerebral Arteriovenous Malformations

    Energy Technology Data Exchange (ETDEWEB)

    Herbert, Christopher, E-mail: cherbert@bccancer.bc.ca [Department of Radiation Oncology, British Columbia Cancer Agency, Vancouver, BC (Canada); Moiseenko, Vitali [Department of Medical Physics, British Columbia Cancer Agency, Vancouver, BC (Canada); McKenzie, Michael [Department of Radiation Oncology, British Columbia Cancer Agency, Vancouver, BC (Canada); Redekop, Gary [Division of Neurosurgery, Vancouver General Hospital, University of British Columbia, Vancouver, BC (Canada); Hsu, Fred [Department of Radiation Oncology, British Columbia Cancer Agency, Abbotsford, BC (Canada); Gete, Ermias; Gill, Brad; Lee, Richard; Luchka, Kurt [Department of Medical Physics, British Columbia Cancer Agency, Vancouver, BC (Canada); Haw, Charles [Division of Neurosurgery, Vancouver General Hospital, University of British Columbia, Vancouver, BC (Canada); Lee, Andrew [Department of Neurosurgery, Royal Columbian Hospital, New Westminster, BC (Canada); Toyota, Brian [Division of Neurosurgery, Vancouver General Hospital, University of British Columbia, Vancouver, BC (Canada); Martin, Montgomery [Department of Medical Imaging, British Columbia Cancer Agency, Vancouver, BC (Canada)

    2012-07-01

    Purpose: To investigate predictive factors in the development of symptomatic radiation injury after treatment with linear accelerator-based stereotactic radiosurgery for intracerebral arteriovenous malformations and relate the findings to the conclusions drawn by Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC). Methods and Materials: Archived plans for 73 patients who were treated at the British Columbia Cancer Agency were studied. Actuarial estimates of freedom from radiation injury were calculated using the Kaplan-Meier method. Univariate and multivariate Cox proportional hazards models were used for analysis of incidence of radiation injury. Log-rank test was used to search for dosimetric parameters associated with freedom from radiation injury. Results: Symptomatic radiation injury was exhibited by 14 of 73 patients (19.2%). Actuarial rate of symptomatic radiation injury was 23.0% at 4 years. Most patients (78.5%) had mild to moderate deficits according to Common Terminology Criteria for Adverse Events, version 4.0. On univariate analysis, lesion volume and diameter, dose to isocenter, and a V{sub x} for doses {>=}8 Gy showed statistical significance. Only lesion diameter showed statistical significance (p < 0.05) in a multivariate model. According to the log-rank test, AVM volumes >5 cm{sup 3} and diameters >30 mm were significantly associated with the risk of radiation injury (p < 0.01). The V{sub 12} also showed strong association with the incidence of radiation injury. Actuarial incidence of radiation injury was 16.8% if V{sub 12} was <28 cm{sup 3} and 53.2% if >28 cm{sup 3} (log-rank test, p = 0.001). Conclusions: This study confirms that the risk of developing symptomatic radiation injury after radiosurgery is related to lesion diameter and volume and irradiated volume. Results suggest a higher tolerance than proposed by QUANTEC. The widely differing findings reported in the literature, however, raise considerable uncertainties.

  7. A dose homogeneity and conformity evaluation between ViewRay and pinnacle-based linear accelerator IMRT treatment plans

    Directory of Open Access Journals (Sweden)

    Daniel L Saenz

    2014-01-01

    Full Text Available ViewRay, a novel technology providing soft-tissue imaging during radiotherapy is investigated for treatment planning capabilities assessing treatment plan dose homogeneity and conformity compared with linear accelerator plans. ViewRay offers both adaptive radiotherapy and image guidance. The combination of cobalt-60 (Co-60 with 0.35 Tesla magnetic resonance imaging (MRI allows for magnetic resonance (MR-guided intensity-modulated radiation therapy (IMRT delivery with multiple beams. This study investigated head and neck, lung, and prostate treatment plans to understand what is possible on ViewRay to narrow focus toward sites with optimal dosimetry. The goal is not to provide a rigorous assessment of planning capabilities, but rather a first order demonstration of ViewRay planning abilities. Images, structure sets, points, and dose from treatment plans created in Pinnacle for patients in our clinic were imported into ViewRay. The same objectives were used to assess plan quality and all critical structures were treated as similarly as possible. Homogeneity index (HI, conformity index (CI, and volume receiving <20% of prescription dose (DRx were calculated to assess the plans. The 95% confidence intervals were recorded for all measurements and presented with the associated bars in graphs. The homogeneity index (D5/D95 had a 1-5% inhomogeneity increase for head and neck, 3-8% for lung, and 4-16% for prostate. CI revealed a modest conformity increase for lung. The volume receiving 20% of the prescription dose increased 2-8% for head and neck and up to 4% for lung and prostate. Overall, for head and neck Co-60 ViewRay treatments planned with its Monte Carlo treatment planning software were comparable with 6 MV plans computed with convolution superposition algorithm on Pinnacle treatment planning system.

  8. LIU 0.5/3000 pulse-periodical linear induction accelerator

    International Nuclear Information System (INIS)

    LIU 0.5/3000 accelerator designed for production of accelerator nanosecond high-current electron beam is described. Its main characteriatics are as follows: electron beam energy in pulse is 50j; electron peak energy - 500 keV; beam pulse power - 15 GW; current amplitude in pulse - 3 kA; beam current duration - 80 ns (at 0.1 level); beam aperture - 8-30cm2; accelerator operates in three modes: single-pulse mode, continuous mode with 50 pulses/s. Succession frequency, mode of pulse train formationfrom 5-10 pulses with equivalent pulse duration in the train up to 200 pulses/s; operating lifetime is ≥ 107 pulses. Accelerator dimensions are 2000x2100x900 mm, its mass - 800 kg

  9. Simulations of the Acceleration of Externally Injected Electrons in a Plasma Excited in the Linear Regime

    CERN Document Server

    Delerue, Nicolas; Jenzer, Stéphane; Kazamias, Sophie; Lucas, Bruno; Maynard, Gilles; Pittman, Moana

    2016-01-01

    We have investigated numerically the coupling between a 10 \\si{MeV} electron bunch of high charge (\\SI{> 100}{pc}) with a laser generated accelerating plasma wave. Our results show that a high efficiency coupling can be achieved using a \\SI{50}{TW}, \\SI{100}{\\micro \\meter} wide laser beam, yielding accelerating field above \\SI{1}{ GV/m}. We propose an experiment where these predictions could be tested.

  10. A new interpretation of large amplitude earthquake acceleration from non-linear local soil-structure interaction

    Energy Technology Data Exchange (ETDEWEB)

    Kojima, Kotaro [Department of Architecture and Architectural Engineering, Kyoto University, Kyoto 615-8540 (Japan); Kamagata, Shuichi [Nuclear Power Department, Kajima Corporation, Tokyo 107-8348 (Japan); Takewaki, Izuru, E-mail: takewaki@archi.kyoto-u.ac.jp [Department of Architecture and Architectural Engineering, Kyoto University, Kyoto 615-8540 (Japan)

    2014-07-01

    Highlights: • A new interpretation of large earthquake accelerations is provided. • Non-linear interaction between an embedded building and its surrounding soil is a key. • A bi-linear restoring-force characteristic with a gap-slip process is used for analysis. • Ricker wavelet and a continuous sweep sinusoidal wave are adopted as input. • The amplification is induced by a higher mode due to the change of a support condition. - Abstract: A new interpretation of large amplitude earthquake accelerations recorded at the Kashiwazaki-Kariwa nuclear power station during the Niigata-ken Chuetsu-oki earthquake in 2007 is provided from the viewpoint of non-linear local interaction between an embedded building and its surrounding soil. An occurrence mechanism is investigated by the dynamic response analysis in which a bi-linear restoring-force characteristic with a gap-slip process is used. The Ricker wavelet and the continuous sweep sinusoidal wave are adopted as an input. The amplification is explained to be induced by an additional higher mode due to the change of a support condition, such as a gap between an embedded building and its surrounding soil.

  11. A new interpretation of large amplitude earthquake acceleration from non-linear local soil-structure interaction

    International Nuclear Information System (INIS)

    Highlights: • A new interpretation of large earthquake accelerations is provided. • Non-linear interaction between an embedded building and its surrounding soil is a key. • A bi-linear restoring-force characteristic with a gap-slip process is used for analysis. • Ricker wavelet and a continuous sweep sinusoidal wave are adopted as input. • The amplification is induced by a higher mode due to the change of a support condition. - Abstract: A new interpretation of large amplitude earthquake accelerations recorded at the Kashiwazaki-Kariwa nuclear power station during the Niigata-ken Chuetsu-oki earthquake in 2007 is provided from the viewpoint of non-linear local interaction between an embedded building and its surrounding soil. An occurrence mechanism is investigated by the dynamic response analysis in which a bi-linear restoring-force characteristic with a gap-slip process is used. The Ricker wavelet and the continuous sweep sinusoidal wave are adopted as an input. The amplification is explained to be induced by an additional higher mode due to the change of a support condition, such as a gap between an embedded building and its surrounding soil

  12. Determination of the Virtual Source Position for the Electron Beams of a Varian Clinac 18 Linear Accelerator: a comparison of experiment methods

    International Nuclear Information System (INIS)

    The dosimetric characteristics of clinical electron beams,generated by medical linear accelerators,depend on the multiple scattering and energy losses in the scattering foil,monitor ion chambers,monitor assembly, collimator jaws and electron applicators.For the majority of clinical situations, it's appropriate to suppose that the diverging broad beam of electrons originates from a virtual point source.The ICRU defines the virtual point source as a source which when placed in vacuum at some distance Svirt ,that lies away from the scattering foil,will produce electrons which obey the inverse square law,and a mean-square angular spread θ2virt. A precise knowledge of the virtual source position is important for radiation dosimetry and treatment planning with clinical electron beams.For example,when a different air-gap from the originally planned,between the applicator and the patient skin is required,or when body inhomogeneities are present.Although the virtual source positions for our Clinac 18 were first determined in 1989, it was necessary to review the subject,due to the recent replacement of the electron gun and the aging conditions of the accelerator and its electron applicators.In addition,we extended the measurements to the 18 MeV electron mode,that were not available at that time

  13. Experimental human challenge infections can accelerate clinical malaria vaccine development

    NARCIS (Netherlands)

    Sauerwein, R.W.; Roestenberg, M.; Moorthy, V.S.

    2011-01-01

    Malaria is one of the most frequently occurring infectious diseases worldwide, with almost 1 million deaths and an estimated 243 million clinical cases annually. Several candidate malaria vaccines have reached Phase IIb clinical trials, but results have often been disappointing. As an alternative to

  14. Error analysis of linear optics measurements via turn-by-turn beam position data in circular accelerators

    CERN Document Server

    Franchi, Andrea

    2016-01-01

    Many advanced techniques have been developed, tested and implemented in the last decades in almost all circular accelerators across the world to measure the linear optics. However, the greater availability and accuracy of beam diagnostics and the ever better correction of linear magnetic lattice imperfections (beta beating at 1% level and coupling at 0.1%) are reaching what seems to be the intrinsic accuracy and precision of different measurement techniques. This paper aims to highlight and quantify, when possible, the limitations of one standard method, the harmonic analysis of turn-by-turn beam position data. To this end, new analytic formulas for the evaluation of lattice parameters modified by focusing errors are derived. The unexpected conclusion of this study is that for the ESRF storage ring (and possibly for any third generation light source operating at ultra-low coupling and with similar diagnostics), measurement and correction of linear optics via orbit beam position data are to be preferred to the...

  15. Dosimetric Characteristics of Detectors in Measurement of Beam Data for Small Fields of Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Ki Lae; Yang, Oh Nam; Choi, Won Sik; Shin, Seong Soo; Ahn, Woo Sang [Dept. of Radiation Oncology, Gangneung Asan Hospital, College of Medicine Ulsan University, Gangneung (Korea, Republic of); Lim, Cheoung Hwan [Dept. of Radiological Science, Hanseo Univesity, Seosan (Korea, Republic of)

    2012-09-15

    Acquisition of accurate beam data is very important to calculate a reliable dose distribution of the treatment planning system for small radiation fields in intensity-modulated radiation therapy(IMRT) and stereotactic radiosurgery(SRS). For the measurement of small fields, the choice of a suitable detector is important due to the shape gradient in profile penumbra, the lack of lateral electronic equilibrium, and the effect of effective detector volume. Therefore, this study was to analyze the dosimetric characteristics of various detectors in measurement of beam data for small fields of linear accelerator. 0.01 cc and 0.13 cc ion chambers (CC01 and CC13) and a stereotactic diode detector(SFD) were used for measurement of small fields. The beam data, including the percent depth dose, output factor, and beam profile were acquired under 6 MV and 15 MV photon beams. Measurements were performed with the field size ranging from 2 x 2 cm{sup 2} to 5 x 5 cm{sup 2}. For field size, the differences of the ratios of PDD{sub 20} and PDD{sub 10} measured by CC01 and SFD detectors were 1.02% and 0.12% for 6 MV and 15 MV photon beams, respectively. For field sizes larger than 3 X 3 cm{sup 2}, the differences of values of PDD{sub 20}/PDD{sub 10} obtained from each detector were 1.15% and 0.71% for 6 MV and 15 MV photon beams, respectively. The output factors obtained from CC01 and SFD for 2 X 2 cm{sup 2} field size were within 0.5% and 1.5% for 6 MV and 15 MV, respectively. The differences in output factor of three detectors for 3 x 3 cm{sup 2} to 5 x 5 cm{sup 2} field sizes were within 0.5%. Profile penumbras measured by the SFD, CC01, and CC13 detectors at three depths were average 2.7 mm and 3.5 mm, 3.4 mm and 4.3 mm, and 5.2 mm and 6.1 mm for 6 MV and 15 MV photon beams, respectively. In conclusion, it could be possible to use of the CC01 and SFD detectors for the measurement of percent depth dose and output factor for 2 x 2 cm{sup 2} field size, and to use of three detectors

  16. An analytic linear accelerator source model for GPU-based Monte Carlo dose calculations

    Science.gov (United States)

    Tian, Zhen; Li, Yongbao; Folkerts, Michael; Shi, Feng; Jiang, Steve B.; Jia, Xun

    2015-10-01

    Recently, there has been a lot of research interest in developing fast Monte Carlo (MC) dose calculation methods on graphics processing unit (GPU) platforms. A good linear accelerator (linac) source model is critical for both accuracy and efficiency considerations. In principle, an analytical source model should be more preferred for GPU-based MC dose engines than a phase-space file-based model, in that data loading and CPU-GPU data transfer can be avoided. In this paper, we presented an analytical field-independent source model specifically developed for GPU-based MC dose calculations, associated with a GPU-friendly sampling scheme. A key concept called phase-space-ring (PSR) was proposed. Each PSR contained a group of particles that were of the same type, close in energy and reside in a narrow ring on the phase-space plane located just above the upper jaws. The model parameterized the probability densities of particle location, direction and energy for each primary photon PSR, scattered photon PSR and electron PSR. Models of one 2D Gaussian distribution or multiple Gaussian components were employed to represent the particle direction distributions of these PSRs. A method was developed to analyze a reference phase-space file and derive corresponding model parameters. To efficiently use our model in MC dose calculations on GPU, we proposed a GPU-friendly sampling strategy, which ensured that the particles sampled and transported simultaneously are of the same type and close in energy to alleviate GPU thread divergences. To test the accuracy of our model, dose distributions of a set of open fields in a water phantom were calculated using our source model and compared to those calculated using the reference phase-space files. For the high dose gradient regions, the average distance-to-agreement (DTA) was within 1 mm and the maximum DTA within 2 mm. For relatively low dose gradient regions, the root-mean-square (RMS) dose difference was within 1.1% and the maximum

  17. TU-C-BRE-02: A Novel, Highly Efficient and Automated Quality Assurance Tool for Modern Linear Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Goddu, S; Sun, B; Yaddanapudi, S; Kamal, G; Mutic, S [Washington University, St. Louis, MO (United States); Baltes, C; Rose, S [Varian Medical Systems iLab GmbH, Baden, Dattwil (Switzerland); Stinson, K [Varian Medical Systems, Palo Alto, CA (United States)

    2014-06-15

    Purpose: Quality assurance (QA) of complex linear accelerators is critical and highly time consuming. Varian’s Machine Performance Check (MPC) uses IsoCal phantom to test geometric and dosimetric aspects of the TrueBeam systems in <5min. In this study we independently tested the accuracy and robustness of the MPC tools. Methods: MPC is automated for simultaneous image-acquisition, using kV-and-MV onboard-imagers (EPIDs), while delivering kV-and-MV beams in a set routine of varying gantry, collimator and couch angles. MPC software-tools analyze the images to test: i) beam-output and uniformity, ii) positional accuracy of isocenter, EPIDs, collimating jaws (CJs), MLC leaves and couch and iii) rotational accuracy of gantry, collimator and couch. 6MV-beam dose-output and uniformity were tested using ionization-chamber (IC) and ICarray. Winston-Lutz-Tests (WLT) were performed to measure isocenter-offsets caused by gantry, collimator and couch rotations. Positional accuracy of EPIDs was evaluated using radio-opaque markers of the IsoCal phantom. Furthermore, to test the robustness of the MPC tools we purposefully miscalibrated a non-clinical TrueBeam by introducing errors in beam-output, energy, symmetry, gantry angle, couch translations, CJs and MLC leaves positions. Results: 6MV-output and uniformity were within ±0.6% for most measurements with a maximum deviation of ±1.0%. Average isocenter-offset caused by gantry and collimator rotations was 0.316±0.011mm agreeing with IsoLock (0.274mm) and WLT (0.41mm). Average rotation-induced couch-shift from MPC was 0.378±0.032mm agreeing with WLT (0.35mm). MV-and-kV imager-offsets measured by MPC were within ±0.15mm. MPC predicted all machine miscalibrations within acceptable clinical tolerance. MPC detected the output miscalibrations within ±0.61% while the MLC and couch positions were within ±0.06mm and ±0.14mm, respectively. Gantry angle miscalibrations were detected within ±0.1°. Conclusions: MPC is a useful tool

  18. A 7MeV S-Band 2998MHz Variable Pulse Length Linear Accelerator System

    CERN Document Server

    Hernandez, Michael; Mishin, Andrey V; Saverskiy, Aleksandr J; Skowbo, Dave; Smith, Richard

    2005-01-01

    American Science and Engineering High Energy Systems Division (AS&E HESD) has designed and commissioned a variable pulse length 7 MeV electron accelerator system. The system is capable of delivering a 7 MeV electron beam with a pulse length of 10 nS FWHM and a peak current of 1 ampere. The system can also produce electron pulses with lengths of 20, 50, 100, 200, 400 nS and 3 uS FWHM with corresponding lower peak currents. The accelerator system consists of a gridded electron gun, focusing coil, an electrostatic deflector system, Helmholtz coils, a standing wave side coupled S-band linac, a 2.6 MW peak power magnetron, an RF circulator, a fast toroid, vacuum system and a PLC/PC control system. The system has been operated at repetition rates up to 250pps. The design, simulations and experimental results from the accelerator system are presented in this paper.

  19. Estimation of peak relative velocity and peak absolute acceleration of linear SDOF systems

    Institute of Scientific and Technical Information of China (English)

    Jianwei Song; Yi-Lun Chu; Zach Liang; George C. Lee

    2007-01-01

    In the seismic analysis and design of structures, the true velocity and absolute acceleration are usually approximated by their corresponding pseudo-values. This approach is simple and works well for structures with small damping (say, less than 15%). When the damping of a structure is enhanced for the purpose of response reduction, it may result in large analysis and design errors. Based on theory of random vibration and the established mechanism of seismic response spectra analysis, a method is developed (1) to predict the relative velocity spectra with any damping ratio level directly from the 5% standard pseudo-acceleration spectrum; and (2) to estimate the peak absolute acceleration. The accuracy of both is validated by using two selected ensembles of ground motion records.

  20. DTL cavity design and beam dynamics for a TAC linear proton accelerator

    Science.gov (United States)

    Caliskan, A.; Yılmaz, M.

    2012-02-01

    A 30 mA drift tube linac (DTL) accelerator has been designed using SUPERFISH code in the energy range of 3-55 MeV in the framework of the Turkish Accelerator Center (TAC) project. Optimization criteria in cavity design are effective shunt impedance (ZTT), transit-time factor and electrical breakdown limit. In geometrical optimization we have aimed to increase the energy gain in each RF gap of the DTL cells by maximizing the effective shunt impedance (ZTT) and the transit-time factor. Beam dynamics studies of the DTL accelerator have been performed using beam dynamics simulation codes of PATH and PARMILA. The results of both codes have been compared. In the beam dynamical studies, the rms values of beam emittance have been taken into account and a low emittance growth in both x and y directions has been attempted.

  1. DTL cavity design and beam dynamics for a TAC linear proton accelerator

    Institute of Scientific and Technical Information of China (English)

    A. Caliskan; M. Yi1maz

    2012-01-01

    A 30 mA drift tube linac (DTL) accelerator has been designed using SUPERFISH code in the energy range of 3-55 MeV in the framework of the Turkish Accelerator Center (TAC) project.Optimization criteria in cavity design are effective shunt impedance (ZTT),transit-time factor and electrical breakdown limit.In geometrical optimization we have aimed to increase the energy gain in each RF gap of the DTL cells by maximizing the effective shunt impedance (ZTT) and the transit-time factor.Beam dynamics studies of the DTL accelerator have been performed using beam dynamics simulation codes of PATH and PARMILA.The results of both codes have been compared.In the beam dynamical studies,the rms values of beam emittance have been taken into account and a low emittance growth in both x and y directions has been attempted.

  2. Simulation of the relativistic electron dynamics and acceleration in a linearly-chirped laser pulse

    CERN Document Server

    Jisrawi, Najeh M; Salamin, Yousef I

    2014-01-01

    Theoretical investigations are presented, and their results are discussed, of the laser acceleration of a single electron by a chirped pulse. Fields of the pulse are modeled by simple plane-wave oscillations and a $\\cos^2$ envelope. The dynamics emerge from analytic and numerical solutions to the relativistic Lorentz-Newton equations of motion of the electron in the fields of the pulse. All simulations have been carried out by independent Mathematica and Python codes, with identical results. Configurations of acceleration from a position of rest as well as from injection, axially and sideways, at initial relativistic speeds are studied.

  3. Measurements of x-rays from the RF systems of the electron-linear accelerator for KEKB

    International Nuclear Information System (INIS)

    RF systems of the electron linear accelerator are important sources of X-rays. In high power RF systems, X-rays become stronger and arc produced from many components. In KEK 8 GeV linear accelerator, the system consists of a klystron, a RF compressor, three RF dividers and a set of wave guides. The RF compressor called SLED, doubles the peak power of the microwave from the 50 MW peak power klystron. The energy of the microwave is divided into four by three RF dividers and goes to four accelerator tubes through the wave guide. X-rays from the klystrons and the SLEDs were measured by using TLDs and survey meters. Some SLEDs emitted X-rays more than others. X-ray spatial distribution around the RF system was measured by using the imaging plate (IP). Characteristic distribution was found around SLEDs based on the electric fields in the cavity. X-rays from the 1st divider were also found. It is well known that klystrons and SLEDs are the important source of X-rays. However, X-rays from other components were not well known. The measurements showed that X-rays were emitted from the center of the dividers and at the edges where they were welded. The electric field at the center is stronger than other part of the divider. A correlation between the electric field and the radiation field in the dividers were seen mostly. (author)

  4. 直线加速器粒子模拟可视化%Particle Simulation Visualization for the Linear Accelerator

    Institute of Scientific and Technical Information of China (English)

    田东; 张智磊; 单桂华; 杨磊; 齐记; 张阔

    2013-01-01

    直线加速器被广泛应用于国防、能源、医疗等多个领域,加速器粒子模拟可视化是研究大规模高能粒子运动规律的重要方法。本文利用OpenGL和GLSL混合编程,给出了一套针对直线加速器粒子的科学模拟可视化与可视分析的方案,可清晰展示粒子在加速过程中的整体状态和运动趋势,体现出高速粒子的分类属性及其变化规律,为直线加速器的诊断分析提供了有效的工具。%Programming mixed with OpenGL and GLSL, we proposed a set of programs of scientiifc visualization and visual analysis for linear accelerator particles, which not only clearly present the particle acceleration process in overall status and exercise trends, but also relfect the high-speed particle properties and their classiifcation attributes, and it provided useful tools for linear accelerator diagnostic analysis.

  5. The international linear collider. Technical design report. Vol. 3.2. Accelerator baseline design

    International Nuclear Information System (INIS)

    The following topics are dealt with: General parameters with layout and systems overview, main linac and SCRF technology, electron source, damping rings, ring to main linac, beam delivery system and machine detector interface, global accelerator control systems, availability with commissioning and operations, conventional facilities and siting, possible upgrade and staging options, project implementation planning, construction schedule, ILC TDR value estimate. (HSI)

  6. Gantry and isocenter displacements of a linear accelerator caused by an add-on micromultileaf collimator

    Energy Technology Data Exchange (ETDEWEB)

    Riis, Hans L.; Zimmermann, Sune J.; Hjelm-Hansen, Mogens [Radiofysisk Laboratorium, Odense University Hospital, Sdr. Boulevard 29, DK-5000 Odense C (Denmark)

    2013-03-15

    Purpose: The delivery of high quality stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT) treatments to the patient requires knowledge of the position of the isocenter to submillimeter accuracy. To meet the requirements the deviation between the radiation and mechanical isocenters must be less than 1 mm. The use of add-on micromultileaf collimators ({mu}MLCs) in SRS and SRT is an additional challenge to the anticipated high-level geometric and dosimetric accuracy of the treatment. The aim of this work was to quantify the gantry excursions during rotation with and without an add-on {mu}MLC attached to the gantry head. In addition, the shift in the position of the isocenter and its correlation to the kV beam center of the cone-beam CT system was included in the study. Methods: The quantification of the gantry rotational performance was done using a pointer supported by an in-house made rigid holder attached to the gantry head of the accelerator. The pointer positions were measured using a digital theodolite. To quantify the effect of an {mu}MLC of 50 kg, the measurements were repeated with the {mu}MLC attached to the gantry head. The displacement of the isocenter due to an add-on {mu}MLC of 50 kg was also investigated. In case of the pointer measurement the {mu}MLC was simulated by weights attached to the gantry head. A method of least squares was applied to determine the position and displacement of the mechanical isocenter. Additionally, the displacement of the radiation isocenter was measured using a ball-bearing phantom and the electronic portal image device system. These measurements were based on 8 MV photon beams irradiated onto the ball from the four cardinal angles and two opposed collimator angles. The measurements and analysis of the data were carried out automatically using software delivered by the manufacturer. Results: The displacement of the mechanical isocenter caused by a 50 kg heavy {mu}MLC was found to be (-0.01 {+-} 0.05, -0

  7. Do technological advances in linear accelerators improve dosimetric outcomes in stereotaxy? A head-on comparison of seven linear accelerators using volumetric modulated arc therapy-based stereotactic planning

    Directory of Open Access Journals (Sweden)

    B Sarkar

    2016-01-01

    Full Text Available Introduction: Linear accelerator (Linac based stereotactic radiosurgery (SRS and stereotactic radiotherapy (SRT using volumetric modulated arc therapy (VMAT has been used for treating small intracranial lesions. Recent development in the Linacs such as inbuilt micro multileaf collimator (MLC and flattening filter free (FFF beam are intended to provide a better dose conformity and faster delivery when using VMAT technique. This study was aimed to compare the dosimetric outcomes and monitor units (MUs of the stereotactic treatment plans for different commercially available MLC models and beam profiles. Materials and Methods: Ten patients having 12 planning target volume (PTV/gross target volume's (GTVs who received the SRS/SRT treatment in our clinic using Axesse Linac (considered reference arm gold standard were considered for this study. The test arms comprised of plans using Elekta Agility with FFF, Elekta Agility with the plane beam, Elekta APEX, Varian Millennium 120, Varian Millennium 120HD, and Elekta Synergy in Monaco treatment planning system. Planning constraints and calculation grid spacing were not altered in the test plans. To objectively evaluate the efficacy of MLC-beam model, the resultant dosimetric outcomes were subtracted from the reference arm parameters. Results: V95%, V100%, V105%, D1%, maximum dose, and mean dose of PTV/GTV showed a maximum inter MLC - beam model variation of 1.5% and 2% for PTV and GTV, respectively. Average PTV conformity index and heterogeneity index shows a variation in the range 0.56–0.63 and 1.08–1.11, respectively. Mean dose difference (excluding Axesse for all organs varied between 1.1 cGy and 74.8 cGy (mean dose = 6.1 cGy standard deviation [SD] = 26.9 cGy and 1.7 cGy–194.5 cGy (mean dose 16.1 cGy SD = 57.2 cGy for single and multiple fraction, respectively. Conclusion: The dosimetry of VMAT-based SRS/SRT treatment plan had minimal dependence on MLC and beam model variations. All tested MLC

  8. Electromagnetic and beam dynamics design of a 5 MeV, 3 kW travelling wave electron linear accelerator

    International Nuclear Information System (INIS)

    An S-band (2856 MHz) 5 MeV, 3 kW traveling wave linear accelerator is currently under design and development at Raja Ramanna Centre for Advanced Technology, Indore. The accelerating structure is a 2π/3 mode constant impedance traveling wave structure, designed to accelerates the 50 keV electron beam from the electron gun to 5 MeV. It comprises of traveling wave buncher cells followed by regular accelerating cells. This paper presents the details of electromagnetic design simulations to fix the mechanical dimensions and tolerances, as well as heat loss calculations in the structure. Comparison of the results obtained from detailed numerical simulations with those obtained from approximate analytical calculations is described in the paper. The beam dynamics simulation from beginning to end of the linac is also performed and the required magnetic field profile for keeping the beam focused in the linac has been evaluated. The aim has been to maximize the capture efficiency with reduced energy spread in a short and compact structure. (author)

  9. Introducing a system for automated control of rotation axes, collimator and laser adjustment for a medical linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, Peter [Department of Radiation Oncology, Karl-Franzens University Medical School, Auenbruggerplatz 32, 8036-Graz (Austria); Bergmann, Helmar [Department of Biomedical Engineering and Physics, University of Vienna (Austria); Stuecklschweiger, Georg [Department of Radiation Oncology, Karl-Franzens University Medical School, Auenbruggerplatz 32, 8036-Graz (Austria); Guss, Helmuth [Department of Radiation Oncology, Karl-Franzens University Medical School, Auenbruggerplatz 32, 8036-Graz (Austria)

    2003-05-07

    Mechanical stability and precise adjustment of rotation axes, collimator and room lasers are essential for the success of radiotherapy and particularly stereotactic radiosurgery with a linear accelerator. Quality assurance procedures, at present mainly based on visual tests and radiographic film evaluations, should desirably be little time consuming and highly accurate. We present a method based on segmentation and analysis of digital images acquired with an electronic portal imaging device (EPID) that meets these objectives. The method can be employed for routine quality assurance with a square field formed by the built-in collimator jaws as well as with a circular field using an external drill hole collimator. A number of tests, performed to evaluate accuracy and reproducibility of the algorithm, yielded very satisfying results. Studies performed over a period of 18 months prove the applicability of the inspected accelerator for stereotactic radiosurgery.

  10. Introducing a system for automated control of rotation axes, collimator and laser adjustment for a medical linear accelerator

    Science.gov (United States)

    Winkler, Peter; Bergmann, Helmar; Stuecklschweiger, Georg; Guss, Helmuth

    2003-05-01

    Mechanical stability and precise adjustment of rotation axes, collimator and room lasers are essential for the success of radiotherapy and particularly stereotactic radiosurgery with a linear accelerator. Quality assurance procedures, at present mainly based on visual tests and radiographic film evaluations, should desirably be little time consuming and highly accurate. We present a method based on segmentation and analysis of digital images acquired with an electronic portal imaging device (EPID) that meets these objectives. The method can be employed for routine quality assurance with a square field formed by the built-in collimator jaws as well as with a circular field using an external drill hole collimator. A number of tests, performed to evaluate accuracy and reproducibility of the algorithm, yielded very satisfying results. Studies performed over a period of 18 months prove the applicability of the inspected accelerator for stereotactic radiosurgery.

  11. Measurements and modeling of gamma absorbed doses due to releases from a linear proton accelerator: experimental design and preliminary results

    International Nuclear Information System (INIS)

    External radiation levels due to positron annihilation radiation from 11C, 13N, and 15O released by the 800 MeV linear proton accelerator at the Los Alamos Meson Physics Facility (LAMPF) have been monitored at a fence-line location both by thermoluminescent dosimeters (TLDs) and high pressure ionization chambers (HPICs). The accelerator is located in irregular terrain consisting of mesas and canyons. Fifteen-minute, accumulated external radiation levels were recorded with the HPICs. Instruments on a nerby meteorological tower concurrently measured wind speed and direction at three levels, temperature at two levels, solar radiation, and rainfall. Real-time radionuclide release rates and stack velocities were measured at the release point with in-stack monitors. This paper presents analyses of short-term radiation levels using HPICs and long-term levels using TLDs. Work being done to develop a computer model to predict external radiation levels based on meteorological data is also discussed

  12. Development of high power toroidal pulse transformer with 10-100 Hz repetition rate for linear induction accelerator

    International Nuclear Information System (INIS)

    Full text: An amorphous-core pulse transformer of 2.5kV /20kV, 20μs, 250J, 100 pps rating has been designed and fabricated for Linear Induction Accelerator. This accelerator will be used to generate intense electron beam pulses at high repetition rate for plastic modification and other material processing applications. The peak power and average power of the pulse transformer are 20MW and 25kW respectively. Modular design based on parallel operation of 6 identical modules has been incorporated in this pulse transformer. Single module has been tested up to 10pps for 10 minute durations. Full transformer assembly has been tested in single pulse mode

  13. Feasibility of an XUV FEL Oscillator Driven by a SCRF Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A. H.; Freund, H. P.; Reinsch, M.

    2014-01-01

    The Advanced Superconducting Test Accelerator (ASTA) facility is currently under construction at Fermi National Accelerator Laboratory. Using a1-ms-long macropulse composed of up to 3000 micropulses, and with beam energies projected from 45 to 800 MeV, the possibility for an extreme ultraviolet (XUV) free-electron laser oscillator (FELO) with the higher energy is evaluated. We have used both GINGER with an oscillator module and the MEDUSA/OPC code to assess FELO saturation prospects at 120 nm, 40 nm, and 13.4 nm. The results support saturation at all of these wavelengths which are also shorter than the demonstrated shortest wavelength record of 176 nm from a storage-ring-based FELO. This indicates linac-driven FELOs can be extended into this XUV wavelength regime previously only reached with single-pass FEL configurations.

  14. Monte Carlo simulation of the CTA/IEAV electron linear accelerator environmental doses using albedo coefficients

    International Nuclear Information System (INIS)

    With the purpose of determining the radiation field in the accelerator environment in an efficient way, it was developed an approximate methodology which uses multigroup albedo coefficients to describe the particle reflection by the walls. This method avoids the particle transport calculation inside the walls, which spends much of the processing time. The Monte Carlo code MCNP was suitably modified to allow the simulation of such calculations. To assess the accuracy achieved with this methodology, very realistic calculations considering the transport of particles inside all the walls are performed. The results showed that the use of albedo coefficients for some walls while allowing the transport of particles inside the other walls in the same calculation gives accurate results, saving significant computational time. The results obtained for the accelerator showed an excellent agreement with the realistic calculation, and that the technique is applicable to large environments. (author)

  15. Probabilistic safety analysis of radiation treatments with linear accelerator (Spanish Ed.)

    International Nuclear Information System (INIS)

    This publication addresses the issue of accidental exposures of radiotherapy patients and how to avoid them. More proactive approaches are required to anticipate and thus avoid situations that could lead to accidental exposures. In this context, the International Atomic Energy Agency (IAEA) and the Ibero American Forum of Radiation and Nuclear and Safety Regulatory Agencies (the FORO) have applied proactive methods, such as probabilistic safety assessment to radiotherapy treatments with accelerators. The methodology and results of this exercise are described in this publication.

  16. Dosimetric study of small circular X-rays fields used in radiosurgery with linear accelerator of 6 MV; Estudo dosimetrico de campos circulares pequenos de raios-X utilizados em radiocirurgia com um acelerador linear de 6 MV

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Jose Carlos da [Hospital Israelita Albert Einstein, Sao Paulo, SP (Brazil). Servico de Radioterapia; Segreto, Roberto Araujo; Segreto, Helena R. Comodo [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Dept. de Medicina. Setor de Radioterapia]. E-mail: josecarlos@einstein.br

    2003-07-01

    Three dosimetric systems were compared regarding dosimetry of small circular x ray fields used in radiosurgery. The dosimetric parameters for circular cones, with diameters ranging from 7 to 30 mm, were acquired using a 6 MV Clinac 600 C linear accelerator. For the measurement of tissue maximum ratios, total scatter factor and radiation field profile, Kodak X-Omat type V radiographic films, and ionization chamber of 0.1 cm{sup 3} and a plane parallel ionization chamber type Markus were used. The plane parallel ionization chamber showed satisfactory results for measurement of tissue maximum ratios and total scatter only for cone sizes larger than 11 mm in diameter. Beam profile showed better spatial resolution when films ere used. The main physical parameters of small circular fields used in radiosurgery can be obtained by combining the dosimetry results of radiation therapy equipment used in current clinical practice. (author)

  17. Cardiac risks in patients with lung cancer in dynamics of carrying out radiation therapy on linear accelerator

    International Nuclear Information System (INIS)

    During radiation therapy (RT) patients on linear accelerator progress of chronic cardiac insufficiency has been pointed out. The patients with associated cardiac diseases in form of IHD, in case of combination of essential hypertension and IHD have shown increase of frequency of complications development of the part of cardiovascular system on RT in 70% og cases. Rhythm disorder and asequence, clear ECG-signs of ischemia in form of repolarization processes, decrease of voltage or T waive inversion, diastole dysfunction on insufficient relaxation type and systolic myocardium dysfunction of left ventricle are to be treated as substantial markers of cardiovascular pathology on RT

  18. A design for a high intensity slow positron facility using forward scattered radiation from an electron linear accelerator

    International Nuclear Information System (INIS)

    A tungsten moderator will be placed behind the target of the Oak Ridge Electron Linear Accelerator (ORELA) to convert gamma radiation to slow positrons. These will be extracted and led through evacuated solenoids to an experiment room. A Penning trap will be used to extend the slow positron pulses to achieve duty factors of 10% or greater. The facility will be used for atomic and molecular physics studies, positron microscopy, and materials research. Operations will be inexpensive and will not interfere with the normal function of ORELA, the measurement of neutron cross sections by flight-time spectrometry. (orig.)

  19. Dosimetry and monitoring of thin X-ray beam produced by linear particle accelerator, for application in radiography

    International Nuclear Information System (INIS)

    The dosimetry and monitoring characteristics of thin X-ray beams, and the application of 4MeV linear particle accelerator to radiosurgery are studied. An addition collimation system, consisted of 3 lead collimators, which allows to obtain thin beams of 6,10 and 15 mm of diameter, was fabricated. The stereo taxic system, together with modifications in dispositives, provide the accuracy required in volum-targed location. The dosimetric informations were determined with silicon detector inserted into water simulator. The isodose curves for each beam, and total isodoses simulating the treatment were established using radiographic emulsions in conditions which reproduce real circunstances of pacient irradiation. (M.C.K.)

  20. Emittance study of a 28 GHz electron cyclotron resonance ion source for the Rare Isotope Science Project superconducting linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Park, Bum-Sik, E-mail: bspark@ibs.re.kr; Hong, In-Seok; Jang, Ji-Ho; Jin, Hyunchang; Choi, Sukjin; Kim, Yonghwan [Rare Isotope Science Project, Institute for Basic Science, Daejeon 305-811 (Korea, Republic of)

    2016-02-15

    A 28 GHz electron cyclotron resonance (ECR) ion source is being developed for use as an injector for the superconducting linear accelerator of the Rare Isotope Science Project. Beam extraction from the ECR ion source has been simulated using the KOBRA3-INP software. The simulation software can calculate charged particle trajectories in three dimensional complex magnetic field structures, which in this case are formed by the arrangement of five superconducting magnets. In this study, the beam emittance is simulated to understand the effects of plasma potential, mass-to-charge ratio, and spatial distribution. The results of these simulations and their comparison to experimental results are presented in this paper.

  1. ANALISIS DOSIS OUTPUT BERKAS ELEKTRON PESAWAT TELETERAPI LINEAR ACCELERATOR (LINAC)TIPE VARIAN HCX 6540 MENGGUNAKAN TRS 398

    OpenAIRE

    Rahayu, Ivonnie Indri

    2015-01-01

    Telah dilakukan penelitian tentang analisis dosis output berkas elektron pesawat teleterapi linear acceleration (LINAC) tipe Varian HCX 6540 dengan energi 6 MeV, 9 MeV, 12 MeV dan 15 MeV menggunakan protokol Technical Report Series (TRS) 398 IAEA. Penelitian ini bertujuan untuk mengukur dosis radiasi output elektron pesawat LINAC tipe HCX 6540 untuk energi 6 MeV, 9 MeV, 12 MeV dan 15 MeV dengan menggunakan water phantom,kemudian hasil tersebut dibandingkan dengan standar pada protokol TRS 398...

  2. VARIAN 23EX直线加速器故障分析%Maintenance for Varian 23EX linear accelerator

    Institute of Scientific and Technical Information of China (English)

    花威; 李军; 谭飞; 陈雪梅

    2013-01-01

    This paper describes four malfunctions of Varian 23EX linear accelerator, puts forward the troubleshooting messure. Four malfunctions are CARR interlock, HWFA interlock of treatment bed, HWFA interlock of collimator and tungsten gate fault.%分析VARIAN 23EX直线加速器CARR联锁、治疗床HWFA联锁、机头HWFA联锁和钨门不到位的4例故障,通过对故障实例的分析及介绍故障排除的方法,为同行提供参考.

  3. Neutron doses in an 8 MeV linear accelerator and an 18 MeV betatron

    International Nuclear Information System (INIS)

    Using uranium fission track dosimeters, dose distributions of neutrons produced by photonuclear reaction in the shielding material were measured near an 8 MeV linear accelerator and an 18 MeV betatron. Dose equivalents, as a function of bremsstrahlung doses in the central beam, are given for different points outside the irradiation field, in particular at the location of the patient. The neutron production was determined as a function of photon energy between 8 and 18 MeV and compared with literature values. (orig./HP)

  4. Emittance study of a 28 GHz electron cyclotron resonance ion source for the Rare Isotope Science Project superconducting linear accelerator

    International Nuclear Information System (INIS)

    A 28 GHz electron cyclotron resonance (ECR) ion source is being developed for use as an injector for the superconducting linear accelerator of the Rare Isotope Science Project. Beam extraction from the ECR ion source has been simulated using the KOBRA3-INP software. The simulation software can calculate charged particle trajectories in three dimensional complex magnetic field structures, which in this case are formed by the arrangement of five superconducting magnets. In this study, the beam emittance is simulated to understand the effects of plasma potential, mass-to-charge ratio, and spatial distribution. The results of these simulations and their comparison to experimental results are presented in this paper

  5. Non-Linear Transmission Line (NLTL) Microwave Source Lecture Notes the United States Particle Accelerator School

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Steven J. [Los Alamos National Laboratory; Carlsten, Bruce E. [Los Alamos National Laboratory

    2012-06-26

    We will quickly go through the history of the non-linear transmission lines (NLTLs). We will describe how they work, how they are modeled and how they are designed. Note that the field of high power, NLTL microwave sources is still under development, so this is just a snap shot of their current state. Topics discussed are: (1) Introduction to solitons and the KdV equation; (2) The lumped element non-linear transmission line; (3) Solution of the KdV equation; (4) Non-linear transmission lines at microwave frequencies; (5) Numerical methods for NLTL analysis; (6) Unipolar versus bipolar input; (7) High power NLTL pioneers; (8) Resistive versus reactive load; (9) Non-lineaer dielectrics; and (10) Effect of losses.

  6. Study of quality assurance regulations for linear accelerators in Korea: A comparison study between the current status in Korea and the international guidelines

    CERN Document Server

    Lee, Hyunho; Jo, Yunhui; Yoon, Myonggeun

    2015-01-01

    Quality assurance (QA) for medical linear accelerators is indispensable for appropriate cancer treatment. Some international organizations and western advanced countries provide QA guidelines for linear accelerators. Currently, QA regulations for linear accelerators in Korean hospitals specify a system in which each hospital stipulates its independent hospital-based protocols for QA procedures (HP_QAPs) and conducts QA based on these HP_QAPs while regulatory authorities verify whether items under these HP_QAPs have been performed. However, because this regulatory method cannot guarantee the quality of universal treatment, and QA items with tolerance criteria are different in many hospitals, the presentation of standardized QA items and tolerance criteria is essential. In this study, QA items in HP_QAPs from various hospitals and those presented by international organizations. Concordance rates between QA items for linear accelerators that were presented by the aforementioned organizations and those currently ...

  7. Simulation and characterization of the RF system and global stability analysis at the REGAE linear electron accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Mayet, Frank

    2012-12-15

    LAOLA (LAboratory for Laser- and beam-driven plasma Acceleration), is a collaboration between groups from DESY and the University of Hamburg. Its mission is to complement basic research in the relatively new field of plasma wakefield acceleration (PWA) by an explicit combination with DESY's conventional, modern accelerators. The linear electron accelerator REGAE is designed to produce sub 10 fs low charge electron bunches with ultra-low emittance at a repetition rate of 50 Hz. The planned experiments include femtosecond electron diffraction (R.J. Dwayne Miller), as well as the probing of laser induced plasma wakefields with well characterized bunches (LAOLA). They all require high bunch time of flight stability down to 10 fs. The REGAE machine consists of two RF cavities, both fed by a single klystron. While the first one - the gun cavity - is used for acceleration of the electrons, the second one - the buncher cavity - can be used to reduce the electron bunch length. This scheme only works for a specific RF phase relation between the two cavities. This thesis is split into two parts. In the first one the implications of the unique two cavity design on day-to-day machine operation are analyzed. To this end an analytical model of the RF system is developed, which is necessary for understanding how to individually adjust the cavity phases. In the second part the influence of the setup on time of flight stability is discussed with an emphasis on phase jitter compensation. RF phase stability measurements reveal that the current machine setup allows for a time of flight stability down to 50 fs right after the gun.

  8. Design of a 5-MA 100-ns linear-transformer-driver accelerator for wire array Z-pinch experiments

    Science.gov (United States)

    Zhou, Lin; Li, Zhenghong; Wang, Zhen; Liang, Chuan; Li, Mingjia; Qi, Jianmin; Chu, Yanyun

    2016-03-01

    The linear-transformer-driver (LTD) is a recently developed pulsed-power technology that shows great promise for a number of applications. These include a Z -pinch-driven fission-fusion-hybrid reactor that is being developed by the Chinese Academy of Engineering Physics. In support of the reactor development effort, we are planning to build an LTD-based accelerator that is optimized for driving wire-array Z -pinch loads. The accelerator comprises six modules in parallel, each of which has eight series 0.8-MA LTD cavities in a voltage-adder configuration. Vacuum transmission lines are used from the interior of the adder to the central vacuum chamber where the load is placed. Thus the traditional stack-flashover problem is eliminated. The machine is 3.2 m tall and 12 m in outer diameter including supports. A prototype cavity was built and tested for more than 6000 shots intermittently at a repetition rate of 0.1 Hz. A novel trigger, in which only one input trigger pulse is needed by utilizing an internal trigger brick, was developed and successfully verified in these shots. A full circuit modeling was conducted for the accelerator. The simulation result shows that a current pulse rising to 5.2 MA in 91 ns (10%-90%) can be delivered to the wire-array load, which is 1.5 cm in height, 1.2 cm in initial radius, and 1 mg in mass. The maximum implosion velocity of the load is 32 cm /μ s when compressed to 0.1 of the initial radius. The maximum kinetic energy is 78 kJ, which is 11.7% of the electric energy stored in the capacitors. This accelerator is supposed to enable a radiation energy efficiency of 20%-30%, providing a high efficient facility for research on the fast Z pinch and technologies for repetition-rate-operated accelerators.

  9. Application of the rf quadrupole in linear accelerators for heavy ion fusion

    International Nuclear Information System (INIS)

    The rf quadrupole (RFQ) linac structure is proposed as an alternative to a system composed of a buncher and independently phased cavities in the low-velocity acceleration section. Beam dynamics simulation studies have demonstrated that with the RFQ (1) high transmission and low beam loss are possible, (2) it is possible to use a low voltage 0.25 MV dc injector and still obtain high output beam currents, (3) the current required from the injector is reduced because of the high transmission of the RFQ, and (4) the output emittance appears to be at least comparable to that expected from a buncher and independently phased cavities

  10. Spatial dependence and origin of the ambient dose due to neutron activation processes in linear accelerators; Dependencia espacial y origen de la dosis ambiental debeda a procesos de activacion neutronica en aceleradores lineales

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Egea, E.; Sanchez Carrascal, M.; Torres Pozas, S.; Monja Ray, P. de la; Perez Molina, J. L.; Madan Rodriguez, C.; Luque Japon, L.; Morera Molina, A.; Hernandez Perez, A.; Barquero Bravo, Y.; Morengo Pedagna, I.; Oliva Gordillo, M. C.; Martin Olivar, R.

    2011-07-01

    In order to try to determine the high dose in the bunker of a Linear Accelerator clinical use trying to measure the spatial dependence of the same from the isocenter to gateway to the board cheeking to establish the origin of it. This dose measurements performed with an ionization chamber at different locations inside the bunker after an irradiation of 400 Monitor Units verifying the dose rate per minute for an hour, and accumulating the dose received during that period of time.

  11. Final Commissioning of the Superconducting Heavy Ion Linear Accelerator at IUAC, Delhi

    Science.gov (United States)

    Datta, Tripti Sekhar; Choudhury, Anup; Chacko, Jacob; Kar, Soumen; Antony, Joby; Babu, Suresh; Kumar, Manoj; Mathuria, D. S.; Sahu, Santosh; Kanjilal, Dinakar

    The superconducting linac as a booster of the 15UD Pelletron accelerator was partly commissioned with one linac module housing eight quarter wave bulk niobium cavities along with the superbuncher and rebuncher cryomodules. Subsequently two more linac cryomodules were added to have in total 24 cavities for acceleration. In addition, a new Linde helium refrigerator of capacity 750 W @ 4.2 K was installed in parallel to the earlier CCI refrigerator. The new refrigerator was integrated with the earlier cryogenics network system through a specially designed liquid helium distribution line without any valve box. The cooling philosophy with this new system is modified to have a faster cool down rate in the critical zone (150 - 70 K) to avoid Q disease. The helium gas pressure fluctuation in the cavities is reduced significantly to have stable RF locking. The full linac is being operated and beams with higher energy are being delivered to the users. The present paper will highlight the performance of the new cryogenic system with respect to cool down rate, and helium pressure fluctuation.

  12. 3D simulations of supernova remnants evolution including non-linear particle acceleration

    CERN Document Server

    Ferrand, Gilles; Ballet, Jean; Teyssier, Romain; Fraschetti, Federico

    2009-01-01

    If a sizeable fraction of the energy of supernova remnant shocks is channeled into energetic particles (commonly identified with Galactic cosmic rays), then the morphological evolution of the remnants must be distinctly modified. Evidence of such modifications has been recently obtained with the Chandra and XMM-Newton X-ray satellites. To investigate these effects, we coupled a semi-analytical kinetic model of shock acceleration with a 3D hydrodynamic code (by means of an effective adiabatic index). This enables us to study the time-dependent compression of the region between the forward and reverse shocks due to the back reaction of accelerated particles, concomitantly with the development of the Rayleigh-Taylor hydrodynamic instability at the contact discontinuity. Density profiles depend critically on the injection level eta of particles: for eta up to about 10^-4 modifications are weak and progressive, for eta of the order of 10^-3 modifications are strong and immediate. Nevertheless, the extension of the...

  13. Be aware of neutrons outside short mazes from 10-MV linear accelerators X-rays in radiotherapy facilities.

    Science.gov (United States)

    Brockstedt, S; Holstein, H; Jakobsson, L; Tomaszewicz, A; Knöös, T

    2015-07-01

    During the radiation survey of a reinstalled 10-MV linear accelerator in an old radiation treatment facility, high dose rates of neutrons were observed. The area outside the maze entrance is used as a waiting room where patients, their relatives and staff other than those involved in the actual treatment can freely pass. High fluence rates of neutrons would cause an unnecessary high effective dose to the staff working in the vicinity of such a system, and it can be several orders higher than the doses received due to X-rays at the same location. However, the common knowledge appears to have been that the effect of neutrons at 10-MV X-ray linear accelerator facilities is negligible and shielding calculations models seldom mention neutrons for this operating energy level. Although data are scarce, reports regarding this phenomenon are now emerging. For the future, it is advocated that contributions from neutrons are considered already during the planning stage of new or modified facilities aimed for 10 MV and that estimated dose levels are verified.

  14. Linear-scaling multipole-accelerated Gaussian and finite-element Coulomb method

    Science.gov (United States)

    Watson, Mark A.; Kurashige, Yuki; Nakajima, Takahito; Hirao, Kimihiko

    2008-02-01

    A linear-scaling implementation of the Gaussian and finite-element Coulomb (GFC) method is presented for the rapid computation of the electronic Coulomb potential. The current work utilizes the fast multipole method (FMM) for the evaluation of the Poisson equation boundary condition. The FMM affords significant savings for small- and medium-sized systems and overcomes the bottleneck in the GFC method for very large systems. Compared to an exact analytical treatment of the boundary, more than 100-fold speedups are observed for systems with more than 1000 basis functions without any significant loss of accuracy. We present CPU times to demonstrate the effectiveness of the linear-scaling GFC method for both one-dimensional polyalanine chains and the challenging case of three-dimensional diamond fragments.

  15. Experimental study of new laser-based alignment system at the KEK B-factory injector linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Suwada, T.; Satoh, M.; Kadokura, E. [Accelerator Laboratory, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2010-12-15

    A new laser-based alignment system for the precise alignment of accelerator components along an ideal straight line at the KEK B-factory injector linear accelerator (linac) is under development. This system is strongly required in the next generation of B-factories for the stable acceleration of high-brightness electron and positron beams with high bunch charges and also for maintaining the stability of injection beams with high quality. A new laser optics for the generation of a so-called Airy beam has been developed for the laser-based alignment system. The laser propagation characteristics both in vacuum and at atmospheric pressure have been systematically investigated in an 82-m-long straight section of the injector linac. The laser-based alignment measurements based on the new laser optics have been carried out with a measurement resolution of {+-}0.1 mm level by using an existing laser detection electronics. The horizontal and vertical displacements from a reference laser line measured using this system are in good agreement with those measured using a standard telescope-based optical alignment technique. In this report, we describe the experimental study in detail along with the basic designs and the recent developments in the new laser-based alignment system.

  16. Many-core graph analytics using accelerated sparse linear algebra routines

    Science.gov (United States)

    Kozacik, Stephen; Paolini, Aaron L.; Fox, Paul; Kelmelis, Eric

    2016-05-01

    Graph analytics is a key component in identifying emerging trends and threats in many real-world applications. Largescale graph analytics frameworks provide a convenient and highly-scalable platform for developing algorithms to analyze large datasets. Although conceptually scalable, these techniques exhibit poor performance on modern computational hardware. Another model of graph computation has emerged that promises improved performance and scalability by using abstract linear algebra operations as the basis for graph analysis as laid out by the GraphBLAS standard. By using sparse linear algebra as the basis, existing highly efficient algorithms can be adapted to perform computations on the graph. This approach, however, is often less intuitive to graph analytics experts, who are accustomed to vertex-centric APIs such as Giraph, GraphX, and Tinkerpop. We are developing an implementation of the high-level operations supported by these APIs in terms of linear algebra operations. This implementation is be backed by many-core implementations of the fundamental GraphBLAS operations required, and offers the advantages of both the intuitive programming model of a vertex-centric API and the performance of a sparse linear algebra implementation. This technology can reduce the number of nodes required, as well as the run-time for a graph analysis problem, enabling customers to perform more complex analysis with less hardware at lower cost. All of this can be accomplished without the requirement for the customer to make any changes to their analytics code, thanks to the compatibility with existing graph APIs.

  17. Radio frequency pulse compression experiments at SLAC (Stanford Linear Accelerator Center)

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, Z.D.; Lavine, T.L.; Menegat, A.; Miller, R.H.; Nantista, C.; Spalek, G.; Wilson, P.B.

    1991-01-01

    Proposed future positron-electron linear colliders would be capable of investigating fundamental processes of interest in the 0.5--5 TeV beam-energy range. At the SLAC Linear Collider (SLC) gradient of about 20 MV/m this would imply prohibitive lengths of about 50--250 kilometers per linac. We can reduce the length by increasing the gradient but this implies high peak power, on the order of 400-- to 1000-MW at X-Band. One possible way to generate high peak power is to generate a relatively long pulse at a relatively low power and compress it into a short pulse with higher peak power. It is possible to compress before DC to RF conversion, as is done using magnetic switching for induction linacs, or after DC to RF conversion, as is done for the SLC. Using RF pulse compression it is possible to boost the 50-- to 100-MW output that has already been obtained from high-power X-Band klystrons the levels required by the linear colliders. In this note only radio frequency pulse compression (RFPC) is considered.

  18. Monte-Carlo simulation of the SL-ELEKTA-20 medical linear accelerator. Dosimetric study of a water phantom

    International Nuclear Information System (INIS)

    In radiotherapy, it is essential to have a precise knowledge of the dose delivered in the target volume and the neighbouring critical organs. To be usable clinically, the models of calculation must take into account the exact characteristics of the beams used and the densities of fabrics. Today we can use sophisticated irradiation techniques and get a more precise assessment of the dose and with a better knowledge of its distribution. Thus in this report, will be detailed a simulation of the head of irradiation of accelerator SL-ELEKTA-20 in electrons mode and a dosimetric study of a water phantom. This study is carried out with the code of simulation Monte Carlo GATE adapted for applications of medical physics; the results are compared with the data obtained by the anticancer center 'Jean Perrin' on a similar accelerator. (author)

  19. 3-D Model of Broadband Emission from Supernova Remnants Undergoing Non-linear Diffusive Shock Acceleration

    CERN Document Server

    Lee, Shiu-Hang; Ellison, Donald C

    2008-01-01

    We present a 3-dimensional model of supernova remnants (SNRs) where the hydrodynamical evolution of the remnant is modeled consistently with nonlinear diffusive shock acceleration occuring at the outer blast wave. The model includes particle escape and diffusion outside of the forward shock, and particle interactions with arbitrary distributions of external ambient material, such as molecular clouds. We include synchrotron emission and cooling, bremsstrahlung radiation, neutral pion production, inverse-Compton (IC), and Coulomb energy-loss. Boardband spectra have been calculated for typical parameters including dense regions of gas external to a 1000 year old SNR. In this paper, we describe the details of our model but do not attempt a detailed fit to any specific remnant. We also do not include magnetic field amplification (MFA), even though this effect may be important in some young remnants. In this first presentation of the model we don't attempt a detailed fit to any specific remnant. Our aim is to devel...

  20. Development of a linear electromagnetic accelerator (Rail Gun) for impact fusion and related studies

    International Nuclear Information System (INIS)

    In order to further enhance the capability of our railgun system, we have developed a 50 cm long; 6 mm square bore railgun accelerating 0.3 g nylon projectiles to 3.1 km/s. Improvements have been carried out in the rail gun design and current source configuration. A simple electrical schematic of the gun is drawn with PSpice 9.2 schematic, which can simulate the electrical pulse that takes place when the driving capacitor bank discharges through the rail gun system and the results obtained are used to predict the performance of the rail gun before actual firing. These series of railgun development have been carried out in the context of our program related to experimental studies of Impact Fusion. (author)

  1. Intracranial stereotactic radiosurgery with an adapted linear accelerator vs. robotic radiosurgery. Comparison of dosimetric treatment plan quality

    Energy Technology Data Exchange (ETDEWEB)

    Treuer, Harald; Hoevels, Moritz; Luyken, Klaus; Visser-Vandewalle, Veerle; Wirths, Jochen; Ruge, Maximilian [University Hospital Cologne, Department of Stereotaxy and Functional Neurosurgery, Cologne (Germany); Kocher, Martin [University Hospital Cologne, Department of Radiotherapy, Cologne (Germany)

    2014-11-22

    Stereotactic radiosurgery with an adapted linear accelerator (linac-SRS) is an established therapy option for brain metastases, benign brain tumors, and arteriovenous malformations. We intended to investigate whether the dosimetric quality of treatment plans achieved with a CyberKnife (CK) is at least equivalent to that for linac-SRS with circular or micromultileaf collimators (microMLC). A random sample of 16 patients with 23 target volumes, previously treated with linac-SRS, was replanned with CK. Planning constraints were identical dose prescription and clinical applicability. In all cases uniform optimization scripts and inverse planning objectives were used. Plans were compared with respect to coverage, minimal dose within target volume, conformity index, and volume of brain tissue irradiated with ≥ 10 Gy. Generating the CK plan was unproblematic with simple optimization scripts in all cases. With the CK plans, coverage, minimal target volume dosage, and conformity index were significantly better, while no significant improvement could be shown regarding the 10 Gy volume. Multiobjective comparison for the irradiated target volumes was superior in the CK plan in 20 out of 23 cases and equivalent in 3 out of 23 cases. Multiobjective comparison for the treated patients was superior in the CK plan in all 16 cases. The results clearly demonstrate the superiority of the irradiation plan for CK compared to classical linac-SRS with circular collimators and microMLC. In particular, the average minimal target volume dose per patient, increased by 1.9 Gy, and at the same time a 14 % better conformation index seems to be an improvement with clinical relevance. (orig.) [German] Stereotaktische Radiochirurgie mit einem adaptierten Linearbeschleuniger (Linac-SRS) ist eine erfolgreiche und etablierte Therapieoption fuer Hirnmetastasen, benigne Hirntumoren und arteriovenoese Malformationen. Ziel war es, zu untersuchen, ob die mit einem CyberKnife (CK) erreichbare

  2. 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

    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-reso...

  3. High-power magnetron transmitter as an RF source for superconducting linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Kazakevich, Grigory, E-mail: gkazakevitch@yahoo.com [Muons, Inc., Batavia, 60510 IL (United States); Johnson, Rolland; Flanagan, Gene; Marhauser, Frank [Muons, Inc., Batavia, 60510 IL (United States); Yakovlev, Vyacheslav; Chase, Brian; Lebedev, Valeri; Nagaitsev, Sergei; Pasquinelli, Ralph; Solyak, Nikolay; Quinn, Kenneth; Wolff, Daniel [Fermilab, Batavia, 60510 IL (United States); Pavlov, Viatcheslav [Budker Institute of Nuclear Physics (BINP), Novosibirsk 630090 (Russian Federation)

    2014-10-01

    A concept of a high-power transmitter utilizing the Continuous Wave (CW) magnetrons, injection-locked by phase-modulated signals, and intended to operate within a wideband control feedback loop in phase and amplitude, is presented. This transmitter is proposed to drive Superconducting RF (SRF) cavities for intensity-frontier GeV-scale proton/ion linacs, such as the projected Fermilab proton linacs or linacs for Accelerator Driven System (ADS). The transmitter consists of two 2-cascade injection-locked magnetrons with outputs combined by a 3-dB hybrid. The transmitter performance was modelled using CW, S-Band, 1 kW magnetrons. A wideband dynamic control of magnetrons, required for the superconducting linacs, was realized using the magnetrons, injection-locked by the phase-modulated signals. The capabilities of the magnetrons injection-locked by the phase-modulated signals and adequateness for feeding of SRF cavities have been verified by measurements of the magnetrons phase performance, by measurements of the transfer function magnitude characteristics of single and 2-cascade magnetrons in the phase modulation domain, and by measurements of spectra of carrier frequency of the magnetron. At the ratio of power of locking signal to output power of ≥−13 dB (in 2-cascade scheme per magnetron) a phase modulation bandwidth is over 1.0 MHz for injection-locked CW single magnetrons and a 2-cascade setup. The carrier frequency spectra (width of ∼1 Hz at the level of −60 dBc) measured with the magnetron, injection-locked by a phase-modulated signal, did not demonstrate broadening at wide range of magnitude and frequency of the phase modulation. The wideband dynamic management of output power of the transmitter model has been first experimentally demonstrated using combined in power magnetrons, injection-locked by the phase-modulated signals. Experiments with the injection-locked magnetrons adequately emulated the wideband dynamic control with a feedback control system

  4. The Quality Control of Intensity Modulated Radiation Therapy (IMRT) for ONCOR Siemens Linear Accelerators Using Film Dosimetry

    International Nuclear Information System (INIS)

    Intensity Modulated Radiation Therapy has made a significant progress in radiation therapy centers in recent years. In this method, each radiation beam is divided into many subfields that create a field with a modulated intensity. Considering the complexity of this method, the quality control for Intensity Modulated Radiation Therapy is a topic of interest for researchers. This article is about the various steps of planning and quality control of Siemens linear accelerators for Intensity Modulated Radiation Therapy, using film dosimetry. This article in addition to review of the techniques, discusses the details of experiments and possible sources of errors which are not mentioned in the protocols and other references. This project was carried out in Isfahan Milad hospital which has two Siemens ONCOR linear accelerators. Both accelerators are equipped with Multi-Leaf Collimators which enables us to perform Intensity Modulated Radiation Therapy delivery in the step-and-shoot method. The quality control consists of various experiments related to the sections of radiation therapy. In these experiments, the accuracy of some components such as treatment planning system, imaging device (CT), Multi-Leaf Collimators, control system of accelerator, and stability of the output are evaluated. The dose verification is performed using film dosimetry method. The films were KODAK-EDR2, which were calibrated before the experiments. One of the important steps is the comparison of the calculated dose with planning system and the measured dose in experiments. The results of the experiments in various steps have been acceptable according to the standard protocols. The calibration of Multi-Leaf Collimators and evaluation of the leakage through the leaves of Multi-Leaf Collimator was performed by using the film dosimetry and visual check. In comparison with calculated and measured dose, more that 80% of the points have to be in agreement within 3% of the value. In our experiments

  5. Repeated delayed onset cerebellar radiation injuries after linear accelerator-based stereotactic radiosurgery for vestibular schwannoma

    OpenAIRE

    Ujifuku, Kenta; Matsuo, Takayuki; Toyoda, Keisuke; Baba, Shiro; Okunaga, Tomohiro; Hayashi, Yukishige; Kamada, Kensaku; MORIKAWA, Minoru; Suyama, Kazuhiko; Nagata, Izumi; Hayashi, Nobuyuki

    2012-01-01

    A 63-year-old woman presented with right hearing disturbance and vertigo. Magnetic resonance (MR) imaging revealed the presence of right vestibular schwannoma (VS). Stereotactic radiosurgery (SRS) was performed with a tumor marginal dose of 14 Gy using two isocenters. She was followed up clinically and neuroradiologically using three-dimensional spoiled gradient-echo MR imaging. She experienced temporal neurological deterioration due to peritumoral edema in her right cerebellar peduncle and p...

  6. Development of hybrid gas detectors for monitoring neutrons induced from the Large Intensity Proton Linear Accelerator

    International Nuclear Information System (INIS)

    The purpose of the research is developments of new hybrid-neutron detectors to measure neutron fluxes where proton accelerators are operated for the purpose of neutron therapy or various industrial applications. The framework of the R and D based upon GEANT simulations was developed for 10B and Gd2O3 hybrid scintillation detectors. The simulation results were applied to design the detector structures and to determine the proper test method where neutron sources were used. The detector response functions for the 10B and Gd2O3 hybrid scintillators were measured by proper calibrations by using neutrons emitted from a 0.5 Ci 252Cf isotope. Furthermore, the detector characteristics were obtained by the comparisons of the neutron signals with those of the gamma-rays emitted from the 137Cs and 60Co sources. We have performed a feasibility study for the future applications of the 10B and Gd2O3 hybrid scintillators to medical imaging of the thermal neutron fields for neutron-beam therapies. A radiation hardness tested for the Resistive Plate Chamber of the CMS/LHC experiment was performed by using the fast neutrons produced by the M50 proton cyclotron in KIRAMS and a 10 mm thick beryllium target. Four tests with cosmic muons have been carried out before and after the neutron irradiation to investigate the effects on the characteristics of the detectors. No significant degradation of the detector characteristics due to the effect, equivalent to 45 Gy, has been observed

  7. Neutron-induced electronic failures around a high-energy linear accelerator

    International Nuclear Information System (INIS)

    Purpose: After a new in-vault CT-on-rails system repeatedly malfunctioned following use of a high-energy radiotherapy beam, we investigated the presence and impact of neutron radiation on this electronic system, as well as neutron shielding options. Methods: We first determined the CT scanner's failure rate as a function of the number of 18 MV monitor units (MUs) delivered. We then re-examined the failure rate with both 2.7-cm-thick and 7.6-cm-thick borated polyethylene (BPE) covering the linac head for neutron shielding. To further examine shielding options, as well as to explore which neutrons were relevant to the scanner failure, Monte Carlo simulations were used to calculate the neutron fluence and spectrum in the bore of the CT scanner. Simulations included BPE covering the CT scanner itself as well as covering the linac head. Results: We found that the CT scanner had a 57% chance of failure after the delivery of 200 MUs. While the addition of neutron shielding to the accelerator head reduced this risk of failure, the benefit was minimal and even 7.6 cm of BPE was still associated with a 29% chance of failure after the delivery of 200 MU. This shielding benefit was achieved regardless of whether the linac head or CT scanner was shielded. Additionally, it was determined that fast neutrons were primarily responsible for the electronic failures. Conclusions: As illustrated by the CT-on-rails system in the current study, physicists should be aware that electronic systems may be highly sensitive to neutron radiation. Medical physicists should therefore monitor electronic systems that have not been evaluated for potential neutron sensitivity. This is particularly relevant as electronics are increasingly common in the therapy vault and newer electronic systems may exhibit increased sensitivity.

  8. Technologies of image guidance and the development of advanced linear accelerator systems for radiotherapy.

    Science.gov (United States)

    Wu, Vincent W C; Law, Maria Y Y; Star-Lack, Josh; Cheung, Fion W K; Ling, C Clifton

    2011-01-01

    As advanced radiotherapy approaches for targeting the tumor and sparing the normal tissues have been developed, the image guidance of therapy has become essential to directing and confirming treatment accuracy. To approach these goals, image guidance devices now include kV on-board imagers, kV/MV cone-beam CT systems, CT-on-rails, and mobile and in-room radiographic/fluoroscopic systems. Nonionizing sources, such as ultrasound and optical systems, and electromagnetic devices have been introduced to monitor or track the patient and/or tumor positions during treatment. In addition, devices have been designed specifically for monitoring and/or controlling respiratory motion. Optimally, image-guided radiation therapy systems should possess 3 essential elements: (1) 3D imaging of soft tissues and tumors, (2) efficient acquisition and comparison of the 3D images, and (3) an efficacious process for clinically meaningful intervention. Understanding and using these tools effectively is central to current radiotherapy practice. The implementation and integration of these devices continue to carry practical challenges, which emphasize the need for further development of the technologies and their clinical applications.

  9. An acceleration technique for the Gauss-Seidel method applied to symmetric linear systems

    Directory of Open Access Journals (Sweden)

    Jesús Cajigas

    2014-06-01

    Full Text Available A preconditioning technique to improve the convergence of the Gauss-Seidel method applied to symmetric linear systems while preserving symmetry is proposed. The preconditioner is of the form I + K and can be applied an arbitrary number of times. It is shown that under certain conditions the application of the preconditioner a finite number of steps reduces the matrix to a diagonal. A series of numerical experiments using matrices from spatial discretizations of partial differential equations demonstrates that both versions of the preconditioner, point and block version, exhibit lower iteration counts than its non-symmetric version. Resumen. Se propone una técnica de precondicionamiento para mejorar la convergencia del método Gauss-Seidel aplicado a sistemas lineales simétricos pero preservando simetría. El precondicionador es de la forma I + K y puede ser aplicado un número arbitrario de veces. Se demuestra que bajo ciertas condiciones la aplicación del precondicionador un número finito de pasos reduce la matriz del sistema precondicionado a una diagonal. Una serie de experimentos con matrices que provienen de la discretización de ecuaciones en derivadas parciales muestra que ambas versiones del precondicionador, por punto y por bloque, muestran un menor número de iteraciones en comparación con la versión que no preserva simetría.

  10. Mechanical quality assurance using light field for linear accelerators with camera calibration.

    Science.gov (United States)

    Park, Kwangwoo; Choi, Wonhoon; Keum, Ki Chang; Lee, Ho; Yoon, Jeongmin; Lee, Chang Geol; Lee, Ik Jae; Cho, Jaeho

    2016-02-01

    Mechanical Quality Assurance (QA) is important to assure spatially precise delivery of external-beam radiation therapy. As an alternative to the conventional-film based method, we have developed a new tool for mechanical QA of LINACs which uses a light field rather than radiation. When light passes through the collimator, a shadow is projected onto a piece of translucent paper and the resulting image is captured by a digital camera via a mirror. With this method, we evaluated the position of the LINAC isocenter and the accuracy of the gantry, collimator, and couch rotation. We also evaluated the accuracy of the digital readouts of the gantry, collimator, and couch rotation. In addition, the treatment couch position indicator was tested. We performed camera calibration as an essential pre-requisite for quantitative measurements of the position of isocenter, the linear motion of the couch, and the rotation angles of the gantry and collimator. Camera calibration reduced the measurement error to submillimeter based on uncertainty in pixel size of the image, while, without calibration, the measurement error of up to 2 mm could occur for an object with a length of 5 cm.

  11. [Linear accelerator-based stereotactic radiosurgery for the treatment of trigeminal neuralgia. Nine years' experience in a single institution].

    Science.gov (United States)

    Serrano-Rubio, A A; Martinez-Manrique, J J; Revuelta-Gutierrez, R; Gomez-Amador, J L; Martinez-Anda, J J; Ponce-Gomez, J A; Moreno-Jimenez, S

    2014-09-16

    INTRODUCTION. Pharmacological treatment is the first therapeutic step towards controlling pain in trigeminal neuralgia, but 25-50% of patients become medication resistant. There are currently several surgical alternatives for treating these patients. AIM. To evaluate the effectiveness and safety of stereotactic radiosurgery for the treatment of patients with trigeminal neuralgia. PATIENTS AND METHODS. A follow-up study was conducted on 30 patients who underwent radiosurgery using a Novalis linear accelerator. Eighty per cent of the dosage was calculated at the isocentre, the entry zone of the root of the trigeminal nerve. The mean follow-up time was 27.5 months (range: 1-65 months). RESULTS. The mean age was 66 years (range: 36-87 years), with a time to progression of 7.1 years (range: 4-27 years). The distribution of the pain was from the right side (63.3%). Of the 30 patients, 27 experienced an improvement (90%) 1.6 months (range: 1 week-4 months) after the treatment; 10 patients (33.3%) scored grade I, and 17 patients (56.6%) obtained a score of grade II. During the follow-up, four patients (14.2%) suffered a relapse; two underwent re-irradiation. Time without recurrence was 62.7 months (range: 54.6-70.8 months). The rate of side effects was 76.7% and only three patients developed facial anaesthesia with loss of the corneal reflex. CONCLUSIONS. The use of the linear accelerator is an effective therapeutic option in the treatment of trigeminal neuralgia, since it provides adequate long-term control of the pain, reduces the use of medication and improves the quality of life. PMID:25190337

  12. Hosing Instability of the Drive Electron Beam in the E157 Plasma-Wakefield Acceleration Experiment at the Stanford Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Blue, Brent Edward; /SLAC /UCLA

    2005-10-10

    In the plasma-wakefield experiment at SLAC, known as E157, an ultra-relativistic electron beam is used to both excite and witness a plasma wave for advanced accelerator applications. If the beam is tilted, then it will undergo transverse oscillations inside of the plasma. These oscillations can grow exponentially via an instability know as the electron hose instability. The linear theory of electron-hose instability in a uniform ion column predicts that for the parameters of the E157 experiment (beam charge, bunch length, and plasma density) a growth of the centroid offset should occur. Analysis of the E157 data has provided four critical results. The first was that the incoming beam did have a tilt. The tilt was much smaller than the radius and was measured to be 5.3 {micro}m/{delta}{sub z} at the entrance of the plasma (IP1.) The second was the beam centroid oscillates in the ion channel at half the frequency of the beam radius (betatron beam oscillations), and these oscillations can be predicted by the envelope equation. Third, up to the maximum operating plasma density of E157 ({approx}2 x 10{sup 14} cm{sup -3}), no growth of the centroid offset was measured. Finally, time-resolved data of the beam shows that up to this density, no significant growth of the tail of the beam (up to 8ps from the centroid) occurred even though the beam had an initial tilt.

  13. Highly accelerated cardiovascular MR imaging using many channel technology: concepts and clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Niendorf, Thoralf [RWTH Aachen, University Hospital, Department of Diagnostic Radiology, Aachen (Germany); Sodickson, Daniel K. [New York University School of Medicine, Department of Radiology, Center for Biomedical Imaging, New York, NY (United States)

    2008-01-15

    Cardiovascular magnetic resonance imaging (CVMRI) is of proven clinical value in the non-invasive imaging of cardiovascular diseases. CVMRI requires rapid image acquisition, but acquisition speed is fundamentally limited in conventional MRI. Parallel imaging provides a means for increasing acquisition speed and efficiency. However, signal-to-noise (SNR) limitations and the limited number of receiver channels available on most MR systems have in the past imposed practical constraints, which dictated the use of moderate accelerations in CVMRI. High levels of acceleration, which were unattainable previously, have become possible with many-receiver MR systems and many-element, cardiac-optimized RF-coil arrays. The resulting imaging speed improvements can be exploited in a number of ways, ranging from enhancement of spatial and temporal resolution to efficient whole heart coverage to streamlining of CVMRI work flow. In this review, examples of these strategies are provided, following an outline of the fundamentals of the highly accelerated imaging approaches employed in CVMRI. Topics discussed include basic principles of parallel imaging; key requirements for MR systems and RF-coil design; practical considerations of SNR management, supported by multi-dimensional accelerations, 3D noise averaging and high field imaging; highly accelerated clinical state-of-the art cardiovascular imaging applications spanning the range from SNR-rich to SNR-limited; and current trends and future directions. (orig.)

  14. Upgrade of the MIT Linear Electrostatic Ion Accelerator (LEIA) for nuclear diagnostics development for Omega, Z and the NIF.

    Science.gov (United States)

    Sinenian, N; Manuel, M J-E; Zylstra, A B; Rosenberg, M; Waugh, C J; Rinderknecht, H G; Casey, D T; Sio, H; Ruszczynski, J K; Zhou, L; Gatu Johnson, M; Frenje, J A; Séguin, F H; Li, C K; Petrasso, R D; Ruiz, C L; Leeper, R J

    2012-04-01

    The MIT Linear Electrostatic Ion Accelerator (LEIA) generates DD and D(3)He fusion products for the development of nuclear diagnostics for Omega, Z, and the National Ignition Facility (NIF). Significant improvements to the system in recent years are presented. Fusion reaction rates, as high as 10(7) s(-1) and 10(6) s(-1) for DD and D(3)He, respectively, are now well regulated with a new ion source and electronic gas control system. Charged fusion products are more accurately characterized, which allows for better calibration of existing nuclear diagnostics. In addition, in situ measurements of the on-target beam profile, made with a CCD camera, are used to determine the metrology of the fusion-product source for particle-counting applications. Finally, neutron diagnostics development has been facilitated by detailed Monte Carlo N-Particle Transport (MCNP) modeling of neutrons in the accelerator target chamber, which is used to correct for scattering within the system. These recent improvements have resulted in a versatile platform, which continues to support the existing nuclear diagnostics while simultaneously facilitating the development of new diagnostics in aid of the National Ignition Campaign at the National Ignition Facility.

  15. The effect of the presence of the patient on the particles dose estimations in high energy linear accelerator mazes

    Directory of Open Access Journals (Sweden)

    Jillali Ghassoun

    2015-09-01

    Full Text Available Purpose: Medical accelerators operating above 10 MV are a source of undesirable neutron radiations which contaminate the therapeutic photon beam. These photo-neutrons which contaminate the therapeutic beam can also generate secondary gamma rays, via inelastic and capture reactions, which increase the undesirable dose to the patient body, the oncology staff and the general public. The purpose of the present work is to investigate, through Monte Carlo simulation, the effect of the presence of the patient on the neutron and gamma rays dose calculations. Methods: To illustrate this effect, the MCNP5 code was used to model a radiotherapy room of a medical linear accelerator operating at 18 MV and to calculate the neutron and the secondary gamma ray energy spectra and the dose equivalent, at various points along the centerline of the maze, in the absence and presence of the patient. Results and Conclusion: The obtained results show a significant change in the neutron energy spectra in the presence of the patient especially in the thermal neutron energy region. The results also indicate that the presence of a patient does not affect the simulated neutron and gamma rays dose equivalents at the maze entrance for mazes greater than 3 m long. A significant change in dose equivalent calculated values was observed when the length of the maze is less than 3 m.

  16. Accelerated oral nanomedicine discovery from miniaturized screening to clinical production exemplified by paediatric HIV nanotherapies

    Science.gov (United States)

    Giardiello, Marco; Liptrott, Neill J.; McDonald, Tom O.; Moss, Darren; Siccardi, Marco; Martin, Phil; Smith, Darren; Gurjar, Rohan; Rannard, Steve P.; Owen, Andrew

    2016-01-01

    Considerable scope exists to vary the physical and chemical properties of nanoparticles, with subsequent impact on biological interactions; however, no accelerated process to access large nanoparticle material space is currently available, hampering the development of new nanomedicines. In particular, no clinically available nanotherapies exist for HIV populations and conventional paediatric HIV medicines are poorly available; one current paediatric formulation utilizes high ethanol concentrations to solubilize lopinavir, a poorly soluble antiretroviral. Here we apply accelerated nanomedicine discovery to generate a potential aqueous paediatric HIV nanotherapy, with clinical translation and regulatory approval for human evaluation. Our rapid small-scale screening approach yields large libraries of solid drug nanoparticles (160 individual components) targeting oral dose. Screening uses 1 mg of drug compound per library member and iterative pharmacological and chemical evaluation establishes potential candidates for progression through to clinical manufacture. The wide applicability of our strategy has implications for multiple therapy development programmes. PMID:27767027

  17. Diffusion bonding and brazing of high purity copper for linear collider accelerator structures

    Science.gov (United States)

    Elmer, J. W.; Klingmann, J.; van Bibber, K.

    2001-05-01

    Diffusion bonding and brazing of high purity copper were investigated to develop procedures for joining precision machined copper components for the Next Linear Collider (NLC). Diffusion bonds were made over a range of temperatures from 400 °C to 1000 °C, under two different loading conditions [3.45 kPa (0.5 psi) and 3.45 MPa (500 psi)], and on two different diamond machined surface finishes. Brazes were made using pure silver, pure gold, and gold-nickel alloys, and different heating rates produced by both radiation and induction heating. Braze materials were applied by both physical vapor deposition (PVD) and conventional braze alloy shims. Results of the diffusion bonding experiments showed that bond strengths very near that of the copper base metal could be made at bonding temperatures of 700 °C or higher at 3.45 MPa bonding pressure. At lower temperatures, only partial strength diffusion bonds could be made. At low bonding pressures (3.45 kPa), full strength bonds were made at temperatures of 800 °C and higher, while no bonding (zero strength) was observed at temperatures of 700 °C and lower. Observations of the fracture surfaces of the diffusion bonded samples showed the effects of surface finish on the bonding mechanism. These observations clearly indicate that bonding began by point asperity contact, and flatter surfaces resulted in a higher percentage of bonded area under similar bonding conditions. Results of the brazing experiments indicated that pure silver worked very well for brazing under both conventional and high heating rate scenarios. Similarly, pure silver brazed well for both the PVD layers and the braze alloy shims. The gold and gold-containing brazes had problems, mainly due to the high diffusivity of gold in copper. These problems led to the necessity of overdriving the temperature to ensure melting, the presence of porosity in the joint, and very wide braze joints. Based on the overall findings of this study, a two-step joining method

  18. SU-E-T-597: Parameterization of the Photon Beam Dosimetry for a Commercial Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lebron, S; Lu, B; Yan, G; Kahler, D; Li, J; Barraclough, B; Liu, C [Univ Florida, Gainesville, FL (United States)

    2015-06-15

    Purpose: In radiation therapy, accurate data acquisition of photon beam dosimetric quantities is important for (1) beam modeling data input into a treatment planning system (TPS), (2) comparing measured and TPS modelled data, (3) a linear accelerator’s (linac) beam characteristics quality assurance process, and (4) establishing a standard data set for data comparison, etcetera. Parameterization of the photon beam dosimetry creates a portable data set that is easy to implement for different applications such as those previously mentioned. The aim of this study is to develop methods to parameterize photon percentage depth doses(PDD), profiles, and total scatter output factors(Scp). Methods: Scp, PDDs and profiles for different field sizes (from 2×2 to 40×40cm{sup 2}), depths and energies were measured in a linac using a three-dimensional water tank. All data were smoothed and profile data were also centered, symmetrized and geometrically scaled. The Scp and PDD data were analyzed using exponential functions. For modelling of open and wedge field profiles, each side was divided into three regions described by exponential, sigmoid and Gaussian equations. The model’s equations were chosen based on the physical principles described by these dosimetric quantities. The equations’ parameters were determined using a least square optimization method with the minimal amount of measured data necessary. The model’s accuracy was then evaluated via the calculation of absolute differences and distance–to–agreement analysis in low gradient and high gradient regions, respectively. Results: All differences in the PDDs’ buildup and the profiles’ penumbra regions were less than 2 mm and 0.5 mm, respectively. Differences in the low gradient regions were 0.20 ± 0.20% and 0.50 ± 0.35% for PDDs and profiles, respectively. For Scp data, all differences were less than 0.5%. Conclusion: This novel analytical model with minimum measurement requirements proved to accurately

  19. A study on the development of quality assurance development and dose distribution for medical linear accelerator

    International Nuclear Information System (INIS)

    QA in radiotherapy includes all procedures that ensure consistency of the medical prescription and safe administration of that radiotherapy-related prescription, including the coincidence of light and radiation fields, radiation dose measurement, and radiation energy uniformity. In this study, we developed and evaluated a versatile dosimeter that retains accuracy, to realize an integrated QA protocol in clinical radiotherapy. A photoconductor was used as a radiation conversion material in the dosimeter. It is considered that the superior dosimeter is necessary to perform such accurate quality assurance, and the dosimeter with x-ray conversion method shows many advantage comparing to the previous dosimeter with indirect conversion method. From this study, we verified the feasibility of the dosimeter with direct conversion method for the application in radiation therapy and expect that such dosimeter with direct conversion method would alternate the previous dosimeter with indirect conversion method in a few years. Therefore, it is necessary to carry out more study of the dosimeter with the direct conversion method in high energy radiation therapy. Also, the verification and experiments of the dosimeter with a variety of radiation energy like electron beam are needed

  20. The Nano-X Linear Accelerator: A Compact and Economical Cancer Radiotherapy System Incorporating Patient Rotation.

    Science.gov (United States)

    Eslick, Enid M; Keall, Paul J

    2015-10-01

    Rapid technological improvements in radiotherapy delivery results in improved outcomes to patients, yet current commercial systems with these technologies on board are costly. The aim of this study was to develop a state-of-the-art cancer radiotherapy system that is economical and space efficient fitting with current world demands. The Nano-X system is a compact design that is light weight combining a patient rotation system with a vertical 6 MV fixed beam. In this paper, we present the Nano-X system design configuration, an estimate of the system dimensions and its potential impact on shielding cost reductions. We provide an assessment of implementing such a radiotherapy system clinically, its advantages and disadvantages compared to a compact conventional gantry rotating linac. The Nano-X system has several differentiating features from current radiotherapy systems, it is [1] compact and therefore can fit into small vaults, [2] light weight, and [3] engineering efficient, i.e., it rotates a relatively light component and the main treatment delivery components are not under rotation (e.g., DMLCs). All these features can have an impact on reducing the costs of the system. In terms of shielding requirements, leakage radiation was found to be the dominant contributor to the Nano-X vault and as such no primary shielding was necessary. For a low leakage design, the Nano-X vault footprint and concrete volume required is 17 m2 and 35 m3 respectively, compared to 54 m2 and 102 m3 for a conventional compact linac vault, resulting in decreased costs in shielding. Key issues to be investigated in future work are the possible patient comfort concerns associated with the patient rotation system, as well as the magnitude of deformation and subsequent adaptation requirements.

  1. The Nano-X Linear Accelerator: A Compact and Economical Cancer Radiotherapy System Incorporating Patient Rotation.

    Science.gov (United States)

    Eslick, Enid M; Keall, Paul J

    2015-10-01

    Rapid technological improvements in radiotherapy delivery results in improved outcomes to patients, yet current commercial systems with these technologies on board are costly. The aim of this study was to develop a state-of-the-art cancer radiotherapy system that is economical and space efficient fitting with current world demands. The Nano-X system is a compact design that is light weight combining a patient rotation system with a vertical 6 MV fixed beam. In this paper, we present the Nano-X system design configuration, an estimate of the system dimensions and its potential impact on shielding cost reductions. We provide an assessment of implementing such a radiotherapy system clinically, its advantages and disadvantages compared to a compact conventional gantry rotating linac. The Nano-X system has several differentiating features from current radiotherapy systems, it is [1] compact and therefore can fit into small vaults, [2] light weight, and [3] engineering efficient, i.e., it rotates a relatively light component and the main treatment delivery components are not under rotation (e.g., DMLCs). All these features can have an impact on reducing the costs of the system. In terms of shielding requirements, leakage radiation was found to be the dominant contributor to the Nano-X vault and as such no primary shielding was necessary. For a low leakage design, the Nano-X vault footprint and concrete volume required is 17 m2 and 35 m3 respectively, compared to 54 m2 and 102 m3 for a conventional compact linac vault, resulting in decreased costs in shielding. Key issues to be investigated in future work are the possible patient comfort concerns associated with the patient rotation system, as well as the magnitude of deformation and subsequent adaptation requirements. PMID:24949649

  2. Optimal composite scores for longitudinal clinical trials under the linear mixed effects model.

    Science.gov (United States)

    Ard, M Colin; Raghavan, Nandini; Edland, Steven D

    2015-01-01

    Clinical trials of chronic, progressive conditions use rate of change on continuous measures as the primary outcome measure, with slowing of progression on the measure as evidence of clinical efficacy. For clinical trials with a single prespecified primary endpoint, it is important to choose an endpoint with the best signal-to-noise properties to optimize statistical power to detect a treatment effect. Composite endpoints composed of a linear weighted average of candidate outcome measures have also been proposed. Composites constructed as simple sums or averages of component tests, as well as composites constructed using weights derived from more sophisticated approaches, can be suboptimal, in some cases performing worse than individual outcome measures. We extend recent research on the construction of efficient linearly weighted composites by establishing the often overlooked connection between trial design and composite performance under linear mixed effects model assumptions and derive a formula for calculating composites that are optimal for longitudinal clinical trials of known, arbitrary design. Using data from a completed trial, we provide example calculations showing that the optimally weighted linear combination of scales can improve the efficiency of trials by almost 20% compared with the most efficient of the individual component scales. Additional simulations and analytical results demonstrate the potential losses in efficiency that can result from alternative published approaches to composite construction and explore the impact of weight estimation on composite performance.

  3. Neutron equivalent dose rates at the surroundings of the electron linear accelerator operated by the university of Sao Paulo - Physics institute

    International Nuclear Information System (INIS)

    For the determination of the neutron dose rates at the surroundings of an electron linear accelerators it is necessary the knowledge of the neutron spectrum or its mean energy, because the conversion factor of the flux in equivalent dose rates, is strongly dependent on the neutron energy. Taking this fact into consideration, equivalent dose rates were determined in the three representative sites of the IF/USP Linear Electron Accelerator. Also, due to the radiation field be pulsed, a theoretical and experimental study has been realized to evaluate the effect produced by the variation of the field on the detector. (author)

  4. Comparison of two methods for assessing leakage radiation dose around the head of the medical linear accelerators

    Institute of Scientific and Technical Information of China (English)

    Ehab M Attalla

    2013-01-01

    Objective:The aim of this study was to measure the leakage by two methods with ion chamber and ready packs film, and to investigate the feasibility and the advantages of using two dosimetry methods for assessing leakage radiation around the head of the linear accelerators. Methods:Measurements were performed using a 30 cm3 ion chamber;the gantry at 0°, the X-ray head at 0°, the field size at between the central axis and a plane surface at a FSD of 100 as a reference, a series of concentric circles having radi of 50, 75, and 100 cm with their common centre at the reference point. The absorbed dose was measured at the reference point, and this would be used as the reference dose. With the diaphragm closed, the measurements were taken along the circumference of the three circles and at 45° intervals. Results:Leakage radiations while the treatment head was in the vertical position varied between 0.016%–0.04%. With the head lying horizontal y, leak-age radiation was the same order magnitude and varied between 0.02%–0.07%. In the second method, the verification was accomplished by closing the col imator jaws and covering the head of the treatment unit with the ready pack films. The films were marked to permit the determination of their positions on the machine after exposed and processed. With the diaphragm closed, and the ready packs films around the linear accelerator the beam turned on for 2500 cGy (2500 MU). The optical den-sity of these films was measured and compared with this of the reference dose. Leakage radiation varied according to the film positions and the magnitude of leakage was between 0.005%–0.075%. Conclusion:The dif erences between the values of the leakage radiation levels observed at dif erent measurement points do not only reflect dif erences in the ef ective shielding thickness of the head wal , but are also related to dif erences in the distances between the target and the measurement points. The experimental errors involved in dosimetric

  5. Out-of-field doses and neutron dose equivalents for electron beams from modern Varian and Elekta linear accelerators.

    Science.gov (United States)

    Cardenas, Carlos E; Nitsch, Paige L; Kudchadker, Rajat J; Howell, Rebecca M; Kry, Stephen F

    2016-01-01

    Out-of-field doses from radiotherapy can cause harmful side effects or eventually lead to secondary cancers. Scattered doses outside the applicator field, neutron source strength values, and neutron dose equivalents have not been broadly investigated for high-energy electron beams. To better understand the extent of these exposures, we measured out-of-field dose characteristics of electron applicators for high-energy electron beams on two Varian 21iXs, a Varian TrueBeam, and an Elekta Versa HD operating at various energy levels. Out-of-field dose profiles and percent depth-dose curves were measured in a Wellhofer water phantom using a Farmer ion chamber. Neutron dose was assessed using a combination of moderator buckets and gold activation foils placed on the treatment couch at various locations in the patient plane on both the Varian 21iX and Elekta Versa HD linear accelerators. Our findings showed that out-of-field electron doses were highest for the highest electron energies. These doses typically decreased with increasing distance from the field edge but showed substantial increases over some distance ranges. The Elekta linear accelerator had higher electron out-of-field doses than the Varian units examined, and the Elekta dose profiles exhibited a second dose peak about 20 to 30 cm from central-axis, which was found to be higher than typical out-of-field doses from photon beams. Electron doses decreased sharply with depth before becoming nearly constant; the dose was found to decrease to a depth of approximately E(MeV)/4 in cm. With respect to neutron dosimetry, Q values and neutron dose equivalents increased with electron beam energy. Neutron contamination from electron beams was found to be much lower than that from photon beams. Even though the neutron dose equivalent for electron beams represented a small portion of neutron doses observed under photon beams, neutron doses from electron beams may need to be considered for special cases. PMID:27455499

  6. Main of probabilistic safety assessment (PSA) of the radiotherapy treatment process with a linear accelerator for medical purposes (linac)

    International Nuclear Information System (INIS)

    The radiation safety assessments traditionally have been based on analyzing the lessons you learn of new events that are becoming known. Although these methods are very valuable, their main limitation is that only cover known events and leave without consider other possible failures that have occurred or have not been published, This does not mean they can not occur. Other tools to analyze prospectively the safety, among which found Probabilistic Safety Assessment (PSA). This paper summarizes the project of American Forum of agencies radiological and nuclear regulators aimed at applying the methods of APS treatment process with a linear accelerator. We defined as unintended consequences accidental exposures both single patient and multiple patients. FMEA methodology was used to define events initiators of accidents and methods of event trees and trees failure to identify the accident sequences that may occur. A Once quantified the frequency of occurrence of accidental sequences Analyses of importance in determining the most recent events significant from the point of view of safety. We identified 158 of equipment failure modes and 295 errors human if they occurred would have the potential to cause the accidental exposures defined. We studied 118 of initiating events accident and 120 barriers. We studied 434 accident sequences. The accidental exposure of a single patient were 40 times likely that multiple patients. 100% of the total frequency of accidental exposures on a single patient is caused by human errors . 8% of the total frequency of accidental exposures on multiple patients initiating events may occur by equipment failure (Computerized tomography, treatment planning system, throttle linear) and 92% by human error. As part of the and recommendations of the study presents the events that are more contribution on the reduction of risk of accidental exposure. (author)

  7. Potential clinical impact of laser-accelerated beams in cancer ion therapy

    Science.gov (United States)

    Obcemea, Ceferino

    2016-09-01

    In this article, I present three advantages of plasma-accelerated ion beams for cancer therapy. I discuss how: 1. low-emittance and well-collimated beams are advantageous in proximal normal tissue-sparing; 2. highly-peaked quasi-monoenergetic beams are ideal for fast energy selection and switching in Pencil Beam Scanning (PBS) as a treatment delivery; 3. high fluence and ultra-short pulse delivery produce collective excitations in the medium and enhance the stopping power. This in turn produces denser ionization track signatures (spurs, blobs, etc.) in target tumors, higher linear energy transfer, higher Bragg peak, and higher radiobiological effectiveness at the micro-level.

  8. A study on the effect of using a flattening filter in a medical linear accelerator on the dose distribution

    Science.gov (United States)

    Kim, Young-Jae; Dong, Kyung-Rae; Chung, Woon-Kwan; Lim, Chang-Seon; Jeong, Cheon-Soo; Seo, Yoon-Jeong

    2014-03-01

    This study compared the dependence of the tissue maximum ratio (TMR) and the beam profile on the use of a flattening filter when a linear accelerator is used for radiation exposure of a small field size. To examine change according to the field size, we limit the collimator size to 1, 2 and 3 cm. A water phantom and an ion chamber are used to measure each TMR while a diode is used to obtain the beam profile. The TMR is approximately 4% higher at a depth of 10 cm in the normal mode than it is in the stereotactic radiosurgery (SRS) mode and approximately 8% higher at a depth of 20 cm in the normal mode than it is in the SRS mode. According to the measurement results for the beam profile, the dose decreases slightly faster in the SRS mode than in the normal mode. On the other hand, the two modes do not show any significant difference because similar shapes are observed in the two modes. According to the analysis results for the TMR and the beam profile for a small field size, there are almost no differences between the normal mode and the SRS mode. Therefore, the SRS mode can be used to increase the dose rate in radiation treatments that use a small field size and to reduce the time for treatment.

  9. Resultant linear acceleration of an instrumented head form does not differ between junior and collegiate taekwondo athletes’ kicks

    Institute of Scientific and Technical Information of China (English)

    David O’Sullivan; Gabriel P. Fife; Willy Pieter; Taehee Lim; Insik Shin

    2016-01-01

    Objective: The purpose of this study was to compare the effects of various taekwondo kicks and age (school level) in absolute terms and relative body mass on the resultant linear acceleration (RLA) of an instrumented head form. Methods: Forty-eight male (middle school: 16; high school: 16; university: 16) taekwondo athletes were recruited for this study. Subjects performed 10 turning, 10 jump spinning hook, and 10 jump back kicks on a Hybrid II head mounted on a height-adjustable frame. Results: A 2-way (School × Kick) MANOVA was used to determine the differences in RLA between schools (age groups) by type of kick. There was no univariate School main effect for absolute RLA (η2=0.06) and RLA relative to body mass (η2=0.06). No univariate Kick main effects were found for absolute (η2=0.06) and relative RLA (η2=0.06). Conclusion: It is of concern that RLA did not significantly differ between school levels, implying that young taekwondo athletes generate similar forces to their adult counterparts, possibly exposing young athletes to an increased risk for head injuries.

  10. Final Environmental Assessment for the construction and operation of an office building at the Stanford Linear Accelerator Center. Part 2

    International Nuclear Information System (INIS)

    The Department of Energy (DOE) has prepared an Environmental Assessment (EA), DOE/EA-1107, analyzing the environmental effects relating to the construction and operation of an office building at the Stanford Linear Accelerator Center (SLAC). SLAC is a national facility operated by Stanford University, California, under contract with DOE. The center is dedicated to research in elementary particle physics and in those fields that make use of its synchrotron facilities. The objective for the construction and operation of an office building is to provide adequate office space for existing SLAC Waste Management (WM) personnel, so as to centralize WM personnel and to make WM operations more efficient and effective. Based on the analyses in the EA, the DOE has determined that the proposed action does not constitute a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act of 1969 (NEPA). Therefore, the preparation of an Environmental Impact Statement is not required. This report contains the Environmental Assessment, as well as the Finding of No Significant Impact (FONSI)

  11. SU-E-T-627: Failure Modes and Effect Analysis for Monthly Quality Assurance of Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Xie, J [Fudan University shanghai cancer center, Shanghai, Shanghai (China); Xiao, Y [Thomas Jefferson UniversityHospital, Philadelphia, PA (United States); Wang, J; Peng, J; Lu, S [Fudan University Shanghai Cancer Center, Shanghai, Shanghai (China); Hu, W [Fudan University Shanghai Caner Center, Shanghai, Shanghai (China)

    2014-06-15

    Purpose: To develop and implement a failure mode and effect analysis (FMEA) on routine monthly Quality Assurance (QA) tests (physical tests part) of linear accelerator. Methods: A systematic failure mode and effect analysis method was performed for monthly QA procedures. A detailed process tree of monthly QA was created and potential failure modes were defined. Each failure mode may have many influencing factors. For each factor, a risk probability number (RPN) was calculated from the product of probability of occurrence (O), the severity of effect (S), and detectability of the failure (D). The RPN scores are in a range of 1 to 1000, with higher scores indicating stronger correlation to a given influencing factor of a failure mode. Five medical physicists in our institution were responsible to discuss and to define the O, S, D values. Results: 15 possible failure modes were identified and all RPN scores of all influencing factors of these 15 failue modes were from 8 to 150, and the checklist of FMEA in monthly QA was drawn. The system showed consistent and accurate response to erroneous conditions. Conclusion: The influencing factors of RPN greater than 50 were considered as highly-correlated factors of a certain out-oftolerance monthly QA test. FMEA is a fast and flexible tool to develop an implement a quality management (QM) frame work of monthly QA, which improved the QA efficiency of our QA team. The FMEA work may incorporate more quantification and monitoring fuctions in future.

  12. A novel incoherent x-ray source using the inverse Compton scattering mechanism in a linear accelerator

    International Nuclear Information System (INIS)

    A classical theory to characterize inverse Compton scattering from a pulsed relativistic electron beam colliding head on with a high energy, pulsed, laser beam has been developed and is presented. Agreement between classical and quantum mechanical theories are demonstrated. Analytical expressions for the total and differential powers are shown. Numerical studies are based on the parameters of an existing linear accelerator and existing high energy ruby and CO2 lasers. The electron beam and photon beam profiles are pulsed along and gaussian perpendicular to the direction of motion. Numerical calculations show that the total power scattered from a single 30 MeV, 500 ps pulsed electron beam (3--10 nC) illuminated with a single 5 ns pulse of focused ruby or CO2 photons (10 J) can generate enough X-ray photons to be detected with a sensitive CsI x-ray detector. The scattered power is distributed in a vary narrow conical region in the back scattered direction. This distribution is shown and the properties of the windowless CsI x-ray detector are presented. The tunable property of this VUV/X-ray source is discussed. A comparison with other non-nuclear x-ray source are made

  13. SU-E-T-627: Failure Modes and Effect Analysis for Monthly Quality Assurance of Linear Accelerator

    International Nuclear Information System (INIS)

    Purpose: To develop and implement a failure mode and effect analysis (FMEA) on routine monthly Quality Assurance (QA) tests (physical tests part) of linear accelerator. Methods: A systematic failure mode and effect analysis method was performed for monthly QA procedures. A detailed process tree of monthly QA was created and potential failure modes were defined. Each failure mode may have many influencing factors. For each factor, a risk probability number (RPN) was calculated from the product of probability of occurrence (O), the severity of effect (S), and detectability of the failure (D). The RPN scores are in a range of 1 to 1000, with higher scores indicating stronger correlation to a given influencing factor of a failure mode. Five medical physicists in our institution were responsible to discuss and to define the O, S, D values. Results: 15 possible failure modes were identified and all RPN scores of all influencing factors of these 15 failue modes were from 8 to 150, and the checklist of FMEA in monthly QA was drawn. The system showed consistent and accurate response to erroneous conditions. Conclusion: The influencing factors of RPN greater than 50 were considered as highly-correlated factors of a certain out-oftolerance monthly QA test. FMEA is a fast and flexible tool to develop an implement a quality management (QM) frame work of monthly QA, which improved the QA efficiency of our QA team. The FMEA work may incorporate more quantification and monitoring fuctions in future

  14. Measurements of photo-neutrons from a medical linear accelerator using CR-39 plastic nuclear track detectors

    Science.gov (United States)

    Monson, Jonathan Michael

    Photo-neutrons are produced when x-ray energies exceed 7 MeV. Photo-neutron production varies depending on x-ray beam energy. CR-39 PNTDs were used in this study to measure the neutron absorbed dose and dose equivalent produced by a Varian Clinac 23EX for x-ray beams of 6 and 18 MVp and with a Varian Trilogy using an x-ray beam of 10 MVp. Neutron absorbed dose and dose equivalent were measured at 100 cm SSD at 0, 20, and 40 cm off-axis from the primary beam in air. Using a polyethylene phantom the neutron absorbed dose and dose equivalent were measured at 100 cm SSD from the top of the phantom at 0, 5, and 10 cm from the surface, in the beam central axis and off-axis distances of 20 and 40 cm at a depth of 10 cm. The neutron absorbed dose and dose equivalent from medical linear accelerators have been measured from the LET spectrum of recoiled tracks produced in the CR-39 PNTDs for high energy neutrons (1-20 MeV) and the neutron dose equivalent for low energy ( 100 keV/microm) particles than those detectors exposed in air.

  15. Comparison of the dosimetric parameters in linear accelerators with flattening filter-free (FFF) and flattening filter (FF)

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Anderson S.; Rostelato, Maria Elisa C.M.; Zeituni, Carlos A.; Moura, Eduardo S.; Rodrigues, Bruna T.; Souza, Daiane C.; Tiezzi, Rodrigo; Souza, Carla D.; Melo, Emerson R.; Camargo, Anderson R.; Batista, Talita Q., E-mail: asorgatti@hotmail.com, E-mail: elisaros@ipen.br, E-mail: czeituni@ipen.br, E-mail: edusantos_moura@ig.com.br, E-mail: bteigarodrigues@gmail.com, E-mail: dchristini2013@gmail.com, E-mail: rtiezzi@ipen.br, E-mail: carladdsouza@yahoo.com.br, E-mail: s, E-mail: emermelo@hotmail.com, E-mail: anderson.rogerio.c@hotmail.com, E-mail: ta_litterqbatista@hotmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    This paper discusses the main features associated with the dosimetric parameters between FFF and FF Linacs. A set of Varian TrueBeam Linac and Varian 23EX dosimetric measurements was acquired to perform the experimental measurements. The dose measurements were carried out in a water Blue phantom, with a waterproof ionization chambers: farmer ionization chamber (0.6 cm{sup 3}) and Exradin A1SL(0.053 cm{sup 3}) , for fields 5 x 5, 8 x 8, 10 x 10, 15 x 15, 30 x 30 cm{sup 2}. The 6 MV FFF and FF was the energy used in this work. Percent Depth Dose (PDD) was the dosimetric parameters evaluated using a fixed Source Surface Distance of 100 cm. One depth were applied for the measurements, 10 cm (central axis) from the water surface. The 6 MV FFF showed less penetrating than the 6 MV FF. This is due to the removal flattening filter causes more lower energy photons on the central axis. The field sizes were equivalent for both FFF and FF. The main advantage in operate linear accelerators without flattening filter is due to the high doses rates delivered during the treatment. High doses rates could reduce the patient treatment time and may be beneficial for some treatment techniques such as IMRT and SRT. (author)

  16. Inertial acceleration as a measure of linear vection: An alternative to magnitude estimation. Ph.D. Thesis

    Science.gov (United States)

    Carpenter-Smith, Theodore R.; Futamura, Robert G.; Parker, Donald E.

    1995-01-01

    The present study focused on the development of a procedure to assess perceived self-motion induced by visual surround motion - vection. Using an apparatus that permitted independent control of visual and inertial stimuli, prone observers were translated along their head x-axis (fore/aft). The observers' task was to report the direction of self-motion during passive forward and backward translations of their bodies coupled with exposure to various visual surround conditions. The proportion of 'forward' responses was used to calculate each observer's point of subjective equality (PSE) for each surround condition. The results showed that the moving visual stimulus produced a significant shift in the PSE when data from the moving surround condition were compared with the stationary surround and no-vision condition. Further, the results indicated that vection increased monotonically with surround velocities between 4 and 40/s. It was concluded that linear vection can be measured in terms of changes in the amplitude of whole-body inertial acceleration required to elicit equivalent numbers of 'forward' and 'backward' self-motion reports.

  17. Late course accelerated hyperfractionated radiotherapy for clinical T1-2 esophageal carcinoma

    Institute of Scientific and Technical Information of China (English)

    Kuai-Le Zhao; Yang Wang; Xue-Hui Shi

    2003-01-01

    AIM: This retrospective study was designed to analyze the results and the failure patterns of late course accelerated hyperfractionated radiotherapy for clinical T1-2NoMo esophageal carcinoma. METHODS: From Aug. 1994 to Feb. 2001, 56 patients with clinical T1-2 esophageal carcinoma received late course accelerated hyperfractionated radiotherapy in Cancer Hospital,Fudan University. All patients had been histologically proven to have squamous cell carcinoma (SCC) and were diagnosed to be T1-2NoMo by CT scan. All patients were treated with conventional fractionation (CF) irradiation during the first twothirds course of the treatment to a dose of about 41.4Gy/23fx/4 to 5 weeks, Which was then followed by accelerated hyperfractionation irradiation using reduced fields, twice daily at 1.SGy per fraction, to a dose about 27Gy/18 fx. Thus the total dose was 67-70Gy/40-43fx/40-49 d. RESULTS: The 1-, 3- and 5-year overall survival was 90.9 %,54.6 %, 47.8 % respectively. The 1-, 3- and 5-year local control rate was 90.9 %, 84.5 % and 84.5 %, respectively.Twenty-five percent (14/56) patients had distant metastasis and/or lymph nodes metastasis alone. Eight point nine percent (5/56) patients had local disease alone. Another 3.6 % (2/56) patients had regional relapse and distant metastasis. CONCLUSION: Late course accelerated hyperfractionated radiotherapy is effective on clinical T1-2 esophageal carcinoma.The main failure pattern is distant metastasis.

  18. Determination of the 20 MeV linear accelerator, new injector for the synchrotron Saturne. Choice of the electrical and dynamical particle parameters

    International Nuclear Information System (INIS)

    This report takes place in the general determination of the 20 MeV linear accelerator which will be the new Saturne injector; it deals with particle dynamics. Starting from beam requirements at the output of the linac, cells lengths with variable synchronous phase angle, buncher and de-buncher parameters, beam emittances at the output in several phase spaces are successively determined. (author)

  19. Experience of micromultileaf collimator linear accelerator based single fraction stereotactic radiosurgery: Tumor dose inhomogeneity, conformity, and dose fall off

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Linda X.; Garg, Madhur; Lasala, Patrick; Kim, Mimi; Mah, Dennis; Chen, Chin-Cheng; Yaparpalvi, Ravindra; Mynampati, Dinesh; Kuo, Hsiang-Chi; Guha, Chandan; Kalnicki, Shalom [Department of Radiation Oncology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Neurosurgery, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Epidemiology and Population Health, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Radiation Oncology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States)

    2011-03-15

    Purpose: Sharp dose fall off outside a tumor is essential for high dose single fraction stereotactic radiosurgery (SRS) plans. This study explores the relationship among tumor dose inhomogeneity, conformity, and dose fall off in normal tissues for micromultileaf collimator (mMLC) linear accelerator (LINAC) based cranial SRS plans. Methods: Between January 2007 and July 2009, 65 patients with single cranial lesions were treated with LINAC-based SRS. Among them, tumors had maximum diameters {<=}20 mm: 31; between 20 and 30 mm: 21; and >30 mm: 13. All patients were treated with 6 MV photons on a Trilogy linear accelerator (Varian Medical Systems, Palo Alto, CA) with a tertiary m3 high-resolution mMLC (Brainlab, Feldkirchen, Germany), using either noncoplanar conformal fixed fields or dynamic conformal arcs. The authors also created retrospective study plans with identical beam arrangement as the treated plan but with different tumor dose inhomogeneity by varying the beam margins around the planning target volume (PTV). All retrospective study plans were normalized so that the minimum PTV dose was the prescription dose (PD). Isocenter dose, mean PTV dose, RTOG conformity index (CI), RTOG homogeneity index (HI), dose gradient index R{sub 50}-R{sub 100} (defined as the difference between equivalent sphere radius of 50% isodose volume and prescription isodose volume), and normal tissue volume (as a ratio to PTV volume) receiving 50% prescription dose (NTV{sub 50}) were calculated. Results: HI was inversely related to the beam margins around the PTV. CI had a ''V'' shaped relationship with HI, reaching a minimum when HI was approximately 1.3. Isocenter dose and mean PTV dose (as percentage of PD) increased linearly with HI. R{sub 50}-R{sub 100} and NTV{sub 50} initially declined with HI and then reached a plateau when HI was approximately 1.3. These trends also held when tumors were grouped according to their maximum diameters. The smallest tumor group

  20. Informed Practice: Students' Clinical Experiences in the Undergraduate Phase of an Accelerated Physician Assistant Program.

    Science.gov (United States)

    Dereczyk, Amy; DeWitt, Rachel

    2016-06-01

    This qualitative study explored the clinical experiences of students in an accelerated physician assistant (PA) program. The participants were either certified nursing assistants (CNAs) or emergency medical technicians-basic (EMTs-B). The study was designed to elicit (1) how the participants perceived their older patients and (2) how the participants' experiences might affect their own future communications, bedside manner, and clinical preparedness as PAs. This study used a focus group to explore students' clinical experiences before the graduate phase of their accelerated PA program. Five female and 2 male PA students (N = 7) participated in the study. All participants were 23 years old and worked as either a CNA or an EMT-B. Results fell into 2 basic themes: informing practice and forming relationships. Regarding the first theme, participants felt that their experience as entry-level health care providers allowed them to improve their communication skills and bedside manner and to provide greater comfort to patients. Regarding the second theme, participants gained appreciation for older people and began to recognize the knowledge deficits and learning needs of their patients. The results suggested that a student's clinical experience as a CNA or an EMT-B before entering a PA program has a positive effect on the student's personal and professional development. The participants acquired greater appreciation and respect for older patients and members of the health care team. PMID:27123599

  1. Using of beam spoilers in linear accelerators with photons of 10 MV; Empleo de degradadores del haz en aceleradores lineales con fotones de 10 MV

    Energy Technology Data Exchange (ETDEWEB)

    Sansogne, R.; Palacios, V.; Arbiser, S. [Vidt Centro Medico- CETRO. Vidt 1924- (1428) Buenos Aires (Argentina)

    1998-12-31

    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 cm{sup 2}, 8 x 8 cm{sup 2} and 10 x 10 cm{sup 2} ; 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)

  2. An Analytic Linear Accelerator Source Model for Monte Carlo dose calculations. II. Model Utilization in a GPU-based Monte Carlo Package and Automatic Source Commissioning

    CERN Document Server

    Tian, Zhen; Li, Yongbao; Shi, Feng; Jiang, Steve B; Jia, Xun

    2015-01-01

    We recently built an analytical source model for GPU-based MC dose engine. In this paper, we present a sampling strategy to efficiently utilize this source model in GPU-based dose calculation. Our source model was based on a concept of phase-space-ring (PSR). This ring structure makes it effective to account for beam rotational symmetry, but not suitable for dose calculations due to rectangular jaw settings. Hence, we first convert PSR source model to its phase-space let (PSL) representation. Then in dose calculation, different types of sub-sources were separately sampled. Source sampling and particle transport were iterated. So that the particles being sampled and transported simultaneously are of same type and close in energy to alleviate GPU thread divergence. We also present an automatic commissioning approach to adjust the model for a good representation of a clinical linear accelerator . Weighting factors were introduced to adjust relative weights of PSRs, determined by solving a quadratic minimization ...

  3. Development of a Magnetron Resonance Frequency Auto Tuning System for Medical Xband [9300 MHz] RF Linear Accelerator

    International Nuclear Information System (INIS)

    The total components of the accelerator are the magnetron, electron gun, accelerating structure, a set of solenoid magnets, four sets of steering coils, a modulator, and a circulator. One of the accelerator components of the accelerating structure is made of oxygen-free high-conductivity copper (OFHC), and its volume is changed according to the ambient temperature. As the volume changes, the resonant frequency of the accelerating structure is changed. Accordingly, the resonance frequency is mismatched between the source of the magnetron and the accelerating structure. An automatic frequency tuning system is automatically matched with the resonant frequency of the magnetron and accelerating structure, which allows a high output power and reliable accelerator operation. An automatic frequency tuning system is composed of a step motor control part for correcting the frequency of the source and power measuring parts, i.e., the forward and reflected power between the magnetron and accelerating structure. In this paper, the design, fabrication, and RF power test of the automatic frequency tuning system for the X-band linac are presented. A frequency tuning system was developed to overcome an unstable accelerator operation owing to the frequency mismatch between the magnetron and accelerating structure. The frequency measurement accuracy is 100 kHz and 0.72 degree per pulse

  4. Development of a Magnetron Resonance Frequency Auto Tuning System for Medical Xband [9300 MHz] RF Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Sung Su; Lee, Byung Cheol [University of Science and Technology, Daejeon (Korea, Republic of); Kim, Yujong; Park, Hyung Dal; Lee, Byeong-No; Joo, Youngwoo; Cha, Hyungki; Lee, Soo Min; Song, Ki Baek [KAERI, Daejeon (Korea, Republic of); Lee, Seung Hyun [Sungkyunkwan University, Suwon (Korea, Republic of)

    2015-05-15

    The total components of the accelerator are the magnetron, electron gun, accelerating structure, a set of solenoid magnets, four sets of steering coils, a modulator, and a circulator. One of the accelerator components of the accelerating structure is made of oxygen-free high-conductivity copper (OFHC), and its volume is changed according to the ambient temperature. As the volume changes, the resonant frequency of the accelerating structure is changed. Accordingly, the resonance frequency is mismatched between the source of the magnetron and the accelerating structure. An automatic frequency tuning system is automatically matched with the resonant frequency of the magnetron and accelerating structure, which allows a high output power and reliable accelerator operation. An automatic frequency tuning system is composed of a step motor control part for correcting the frequency of the source and power measuring parts, i.e., the forward and reflected power between the magnetron and accelerating structure. In this paper, the design, fabrication, and RF power test of the automatic frequency tuning system for the X-band linac are presented. A frequency tuning system was developed to overcome an unstable accelerator operation owing to the frequency mismatch between the magnetron and accelerating structure. The frequency measurement accuracy is 100 kHz and 0.72 degree per pulse.

  5. 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

    International Nuclear Information System (INIS)

    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 lung radiosurgery experience using a FFF linac operating at 2400 MU/min. We reviewed all flattening filter-free (FFF) lung SBRT cases treated at our institution from August 2010 through July 2012. Patients were eligible for inclusion if they had at least one clinical assessment at least 30 days following SBRT. Pulmonary, cardiac, dermatologic, neurologic, and gastrointestinal treatment related toxicities were scored according to CTCAE version 4.0. Toxicity observed within 90 days of SBRT was categorized as acute, whereas toxicity observed more than 90 days from SBRT was categorized as late. Factors thought to influence risk of toxicity were examined to assess relationship to grade > =2 toxicity. Sixty-four patients with >30 day follow up were eligible for inclusion. All patients were treated using 10 MV unflattened photons beams with intensity modulated radiation therapy (IMRT) inverse planning. Median SBRT dose was 48 Gy in 4 fractions (range: 30–60 Gy in 3–5 fractions). Six patients (9%) experienced > = grade 2 acute pulmonary toxicity; no non-pulmonary acute toxicities were observed. In a subset of 49 patients with greater than 90 day follow up (median 11.5 months), 11 pulmonary and three nerve related grade > =2 late toxicities were recorded. Pulmonary toxicities comprised six grade 2, three grade 3, and one each grade 4 and 5 events. Nerve related events were rare and included two cases of grade 2 chest wall pain and one grade 3 brachial plexopathy which spontaneously resolved. No

  6. The effect of a paraffin screen on the neutron dose at the maze door of a 15 MV linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Krmar, M.; Kuzmanović, A. [Physics Department, Faculty of Science, University of Novi Sad, Novi Sad 21000 (Serbia); Nikolić, D. [National Institute for Nanotechnology, Edmonton, Alberta T6G 2M9 (Canada); Kuzmanović, Z. [International Medical Centers, Banja Luka 78000, Republika Srpska, Bosnia and Herzegovina (Bosnia and Herzegowina); Ganezer, K. [Physics Department, California State University Dominguez Hills, Carson, California 90747 (United States)

    2013-08-15

    Purpose: The purpose of this study was to explore the effects of a paraffin screen located at various positions in the maze on the neutron dose equivalent at the maze door.Methods: The neutron dose equivalent was measured at the maze door of a room containing a 15 MV linear accelerator for x-ray therapy. Measurements were performed for several positions of the paraffin screen covering only 27.5% of the cross-sectional area of the maze. The neutron dose equivalent was also measured at all screen positions. Two simple models of the neutron source were considered in which the first assumed that the source was the cross-sectional area at the inner entrance of the maze, radiating neutrons in an isotropic manner. In the second model the reduction in the neutron dose equivalent at the maze door due to the paraffin screen was considered to be a function of the mean values of the neutron fluence and energy at the screen.Results: The results of this study indicate that the equivalent dose at the maze door was reduced by a factor of 3 through the use of a paraffin screen that was placed inside the maze. It was also determined that the contributions to the dosage from areas that were not covered by the paraffin screen as viewed from the dosimeter, were 2.5 times higher than the contributions from the covered areas. This study also concluded that the contributions of the maze walls, ceiling, and floor to the total neutron dose equivalent were an order of magnitude lower than those from the surface at the far end of the maze.Conclusions: This study demonstrated that a paraffin screen could be used to reduce the neutron dose equivalent at the maze door by a factor of 3. This paper also found that the reduction of the neutron dose equivalent was a linear function of the area covered by the maze screen and that the decrease in the dose at the maze door could be modeled as an exponential function of the product φ·E at the screen.

  7. Proposal for an alignment method of the CLIC linear accelerator - From geodesic networks to the active pre-alignment

    International Nuclear Information System (INIS)

    The compact linear collider (CLIC) is the particle accelerator project proposed by the european organization for nuclear research (CERN) for high energy physics after the large hadron collider (LHC). Because of the nano-metric scale of the CLIC leptons beams, the emittance growth budget is very tight. It induces alignment tolerances on the positions of the CLIC components that have never been achieved before. The last step of the CLIC alignment will be done according to the beam itself. It falls within the competence of the physicists. However, in order to implement the beam-based feedback, a challenging pre-alignment is required: 10 μm at 3σ along a 200 m sliding window. For such a precision, the proposed solution must be compatible with a feedback between the measurement and repositioning systems. The CLIC pre-alignment will have to be active. This thesis does not demonstrate the feasibility of the CLIC active pre-alignment but shows the way to the last developments that have to be done for that purpose. A method is proposed. Based on the management of the Helmert transformations between Euclidean coordinate systems, from the geodetic networks to the metrological measurements, this method is likely to solve the CLIC pre-alignment problem. Large scale facilities have been built and Monte-Carlo simulations have been made in order to validate the mathematical modeling of the measurement systems and of the alignment references. When this is done, it will be possible to extrapolate the modeling to the entire CLIC length. It will be the last step towards the demonstration of the CLIC pre-alignment feasibility. (author)

  8. Technique in linear accelerator total body irradiation%直线加速器全身照射技术

    Institute of Scientific and Technical Information of China (English)

    张九堂; 伍志红; 鲁旭蔚; 何金莲

    2001-01-01

    This article describes the physical, technical, and dosimetric aspects of total body irradiation (TBI) that was carried out by using 6MV X-Ray from Varian 2300 C/D Linear Accelerator at a distance of 450 cm from target to the treatment table and at a gantry angle of 270°.The dose to lung tissue was limit by setting the individual lead compensators customized before, and using DPD-510 to monitor the absorbed dose of the reference point the absorbed dose in depth of half of body will be (Din+Dout)/2 after taking treatment in both AP position and PA position.%本文介绍了在直线加速器上实行全身照射的方法,包括治疗床的设计、测量装置的制作、实验参数的测定和照射方法。SSD=450 cm,机架角为270度,患者取侧卧位,前后野和后前野对穿照射,采用分段肺屏蔽办法控制肺的吸收剂量。用多通道半导体剂量仪进行剂量全程监测作为质量控制手段进行质量控制和实现质量保证,用入射表面剂量Din与出射表面剂量Dout之和的一半即(Din+Dout)/2作为对应入射方向上体中层面的吸收剂量。

  9. Solid state tuneable power RF source for S-band klystron used in the indigenous development of medical linear accelerator for radiotherapy

    International Nuclear Information System (INIS)

    Medical Linear Accelerators (LINAC) are being widely used in the treatment of the cancer patients. The requirement of the energy and the particle type depends on the tumour site and its volume. Hence, it is a necessary to design and develop the multiple energy electron medical accelerators. We have successfully indigenously developed, installed and commissioned the 4 MV (Jeevan-Jyoti) and 6 MV (Siddarth) machines for this purpose. The said machines have been type approved by Atomic Energy Regulatory Board (AERB), Mumbai for the treatment of cancer patient. After this achievement we have taken up the project to design and develop the dual mode (Photon and Electron) multiple energy Medical Accelerator. This LINAC will deliver the two photon energies of 6 and 10 MV, whereas five electron energies viz. 6, 9, 12, 15 and 18 MeV. The system has various sub system such as Linear accelerator (radiation source), High power Modulator, Microwave system based on Klystron, Gantry, Patient Support Assembly, Dosimetry, Beam limiting system, control console, etc. In conclusion, we have successfully achieved the precise variation of RF power using this RF source which will be input to klystron amplifier and the accelerator will produce the different energies as per the treatment requirement using the FPGA based control system

  10. A model for the determination of the nominal potential for a linear accelerator; Un modelo para la determinacion del potencial nominal de un acelerador lineal

    Energy Technology Data Exchange (ETDEWEB)

    Gutt, F.; Silva, P.; Guerrero, R.; Diaz, J.; Colmenares, J. [Instituto Venezolano de Investigaciones Cientificas (IVIC), Laboratorio Secundario de Calibracion Dosimetrica (LSCD), Apartado 21827, Caracas 1020 A (Venezuela)

    1998-12-31

    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 cm{sup 2} 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)

  11. A novel method for the measurement of linear body segment parameters during clinical gait analysis.

    Science.gov (United States)

    Geil, Mark D

    2013-09-01

    Clinical gait analysis is a valuable tool for the understanding of motion disorders and treatment outcomes. Most standard models used in gait analysis rely on predefined sets of body segment parameters that must be measured on each individual. Traditionally, these parameters are measured using calipers and tape measures. The process can be time consuming and is prone to several sources of error. This investigation explored a novel method for rapid recording of linear body segment parameters using magnetic-field based digital calipers commonly used for a different purpose in prosthetics and orthotics. The digital method was found to be comparable to traditional in all linear measures and data capture was significantly faster with the digital method, with mean time savings for 10 measurements of 2.5 min. Digital calipers only record linear distances, and were less accurate when diameters were used to approximate limb circumferences. Experience in measuring BSPs is important, as an experienced measurer was significantly faster than a graduate student and showed less difference between methods. Comparing measurement of adults vs. children showed greater differences with adults, and some method-dependence. If the hardware is available, digital caliper measurement of linear BSPs is accurate and rapid.

  12. Calculational parameters of the accelerating-focusing channel of the HF injector for the linear accelerator of the AN USSR IYaI meson factory

    International Nuclear Information System (INIS)

    The results of investigation of RF i.njector (RFI) for the meson factory linac are presented. Investigated are the conditions providing effective bunching of particles, their capture into the acceleration mode, possibilities of change of the bunch output parameters at the expense of the choice of parameters of the accelerating structure and the analysis of electric fields in the four-wire line with electrodes. The main parameters of the RFI are as follows: average radius of the channel 6.23 mm, electric potential on the electrodes 121.9 kV, modu. lation coefficient 1.04-1.69, acceleration efficiency 0.0122- 0.428, the number of bunching periods 14, length 1.3 m. The parameters of the beam have been investigated at current pulse of 50 and 100 μA. The beam current equals 44 mA within the range of the required normalized emittance of 0.15π cmxmrad at the RFI output at beam current of 50 μA; at beam current of 100 μA the part of accelerated particles constituted 75 μA

  13. Equilibrium and linear stability analysis of a class of solutions of a thin ring model for a stationary field electron ring accelerator

    International Nuclear Information System (INIS)

    A class of equilibrium solutions is developed for a thin-ring model of a stationary field electron ring accelerator during the slow-moving electron ring stage. The problem is viewed as a generalized version of the Bernstein-Greene-Kruskal problem, leading to the solution of electron and ion charge densities. Linear stability analysis shows that this class of equilibrium solutions is linearly stable under J = 0 perturbations of all values of the ratio of the speed of the most energetic ions to the speed of the most energetic electrons. The values of the oscillation frequencies and the expressions for their corresponding eigenfunctions are found to exhibit convergence

  14. Radiobiological Characterization of Two Photon-Beam Energies 6 and 15 MV used in Radiotherapy From Linear Accelerator

    International Nuclear Information System (INIS)

    The main objective of this study is to perform radiobiological characterization of two different photon beam energies, 6 MV and 15 MV, from linear accelerator used in radiotherapy, with special regard to late effects of radiation. Two end-points, namely cell survival and micronucleus induction were used for the characterization. Chinese hamster V 79 lung fibroblast cell line to prepare cell culture and to perform the innervate experiments. chromosomes number was counted and found to be 22 chromosomes per cell, this result is in complete agreement with expected 11 pairs of chromosomes representing the genome of this species. Cells were kept in confluent growth for two days and then exposed to two photon beam energies, 6 and 15 MV respectively. Different dose rates were used for the two beam energies, 0.25, 0.5, 1.0, 2.0, 4.0, 7.0 Gy. Cells were counted immediately after irradiation and re seeded, the seeded number of cells was calculated to the dose rate used. Another set of unirradiated cells treated the same as the experimental set was used as a control group. The plating efficiency (PE) was calculated for the control group, then cells were incubated at 37oC for 6 days to construct the survival curve, five samples were counted per dose and the mean was calculated. The two survival curves are similar for photon beam energies (6 and 15 MV) and the surviving fraction was decreased with dose rate. The two curves showed similar values of α and β parameters, this result is expected for the same radiation type (X-ray). For the micronuclei assay three samples for each dose were seeded and incubated at 37oC for 24 hours then Cytochalasin-B was added to block cells in cytokinesis phase of the mitosis. The micronuclei number was counted and plotted with dose. A significant positive correlation was found between dose and micronuclei frequency (P=0.00), moreover, the micronuclei frequency is relatively higher with 15 MV compared with 6 MV energy. This indicates the presence

  15. Statistics in review. Part 2: generalised linear models, time-to-event and time-series analysis, evidence synthesis and clinical trials.

    Science.gov (United States)

    Moran, John L; Solomon, Patricia J

    2007-06-01

    In Part I, we reviewed graphical display and data summary, followed by a consideration of linear regression models. Generalised linear models, structured in terms of an exponential response distribution and link function, are now introduced, subsuming logistic and Poisson regression. Time-to-event ("survival") analysis is developed from basic principles of hazard rate, and survival, cumulative distribution and density functions. Semi-parametric (Cox) and parametric (accelerated failure time) regression models are contrasted. Time-series analysis is explicated in terms of trend, seasonal, and other cyclical and irregular components, and further illustrated by development of a classical Box-Jenkins ARMA (autoregressive moving average) model for monthly ICU-patient hospital mortality rates recorded over 11 years. Multilevel (random-effects) models and principles of meta-analysis are outlined, and the review concludes with a brief consideration of important statistical aspects of clinical trials: sample size determination, interim analysis and "early stopping". PMID:17536991

  16. Improvements in dose accuracy delivered with static-MLC IMRT on an integrated linear accelerator control system

    Energy Technology Data Exchange (ETDEWEB)

    Li Ji; Wiersma, Rodney D.; Stepaniak, Christopher J.; Farrey, Karl J.; Al-Hallaq, Hania A. [Department of Radiation and Cellular Oncology, University of Chicago, 5758 South Maryland Avenue, MC9006, Chicago, Illinois 60637 (United States)

    2012-05-15

    Purpose: Dose accuracy has been shown to vary with dose per segment and dose rate when delivered with static multileaf collimator (SMLC) intensity modulated radiation therapy (IMRT) by Varian C-series MLC controllers. The authors investigated the impact of monitor units (MUs) per segment and dose rate on the dose delivery accuracy of SMLC-IMRT fields on a Varian TrueBeam linear accelerator (LINAC), which delivers dose and manages motion of all components using a single integrated controller. Methods: An SMLC sequence was created consisting of ten identical 10 x 10 cm{sup 2} segments with identical MUs. Beam holding between segments was achieved by moving one out-of-field MLC leaf pair. Measurements were repeated for various combinations of MU/segment ranging from 1 to 40 and dose rates of 100-600 MU/min for a 6 MV photon beam (6X) and dose rates of 800-2400 MU/min for a 10 MV flattening-filter free photon (10XFFF) beam. All measurements were made with a Farmer (0.6 cm{sup 3}) ionization chamber placed at the isocenter in a solid-water phantom at 10 cm depth. The measurements were performed on two Varian LINACs: C-series Trilogy and TrueBeam. Each sequence was delivered three times and the dose readings for the corresponding segments were averaged. The effects of MU/segment, dose rate, and LINAC type on the relative dose variation ({Delta}{sub i}) were compared using F-tests ({alpha} = 0.05). Results: On the Trilogy, large {Delta}{sub i} was observed in small MU segments: at 1 MU/segment, the maximum {Delta}{sub i} was 10.1% and 57.9% at 100 MU/min and 600 MU/min, respectively. Also, the first segment of each sequence consistently overshot ({Delta}{sub i} > 0), while the last segment consistently undershot ({Delta}{sub i} < 0). On the TrueBeam, at 1 MU/segment, {Delta}{sub i} ranged from 3.0% to 4.5% at 100 and 600 MU/min; no obvious overshoot/undershoot trend was observed. F-tests showed statistically significant difference [(1 - {beta}) =1.0000] between the

  17. Relativistic-klystron two-beam-accelerator as a power source for a 1 TeV next linear collider: A systems study

    Energy Technology Data Exchange (ETDEWEB)

    Yu, S.; Goffeney, N. [Lawrence Berkeley Lab., CA (United States); Deadrick, F. [Lawrence Livermore National Lab., CA (United States)] [and others

    1994-10-01

    A physics, engineering, and costing study has been conducted to explore the feasibility of a relativistic-klystron two-beam-accelerator system as a power source candidate for a 1 TeV linear collider. We present a point design example which has acceptable transverse and longitudinal beam stability properties. Preliminary ``bottom-up`` cost estimate yields the full power source system at less than 1 billion dollars. The overall efficiency for rf production is estimated to be 36%.

  18. Impact of adjuvant radiation therapy photon energy on quality of life after breast conservation therapy: Linear accelerator versus the cobalt machine

    OpenAIRE

    Anusheel Munshi; Debnarayan Dutta; Ashwini Budrukkar; Rakesh Jalali; Rajiv Sarin; Sudeep Gupta; Jaya Ghosh; Jyoti Bajpai; Vani Parmar; Nita Nair; Rajendra Badwe

    2012-01-01

    Background: Breast conservative therapy (BCT) is a standard treatment option in early operable breast cancers (OBC) and a select group of large or locally advanced tumors. The present study deals with prospective evaluation of quality of life (QOL) score in consecutive patients treated with BCT employing adjuvant RT treated with either a cobalt machine or a linear accelerator (LA). Material and Methods: Patients of carcinoma breast who underwent BCT were taken into the study. Patients with...

  19. Poster — Thur Eve — 46: Monte Carlo model of the Novalis Classic 6MV stereotactic linear accelerator using the GATE simulation platform

    Energy Technology Data Exchange (ETDEWEB)

    Wiebe, J [Department of Medical Physics, Tom Baker Cancer Centre, Calgary AB (Canada); Department of Physics and Astronomy, University of Calgary, Calgary, AB (Canada); Ploquin, N [Department of Medical Physics, Tom Baker Cancer Centre, Calgary AB (Canada); Department of Physics and Astronomy, University of Calgary, Calgary, AB (Canada); Department of Oncology, University of Calgary, Calgary, AB (Canada)

    2014-08-15

    Monte Carlo (MC) simulation is accepted as the most accurate method to predict dose deposition when compared to other methods in radiation treatment planning. Current dose calculation algorithms used for treatment planning can become inaccurate when small radiation fields and tissue inhomogeneities are present. At our centre the Novalis Classic linear accelerator (linac) is used for Stereotactic Radiosurgery (SRS). The first MC model to date of the Novalis Classic linac was developed at our centre using the Geant4 Application for Tomographic Emission (GATE) simulation platform. GATE is relatively new, open source MC software built from CERN's Geometry and Tracking 4 (Geant4) toolkit. The linac geometry was modeled using manufacturer specifications, as well as in-house measurements of the micro MLC's. Among multiple model parameters, the initial electron beam was adjusted so that calculated depth dose curves agreed with measured values. Simulations were run on the European Grid Infrastructure through GateLab. Simulation time is approximately 8 hours on GateLab for a complete head model simulation to acquire a phase space file. Current results have a majority of points within 3% of the measured dose values for square field sizes ranging from 6×6 mm{sup 2} to 98×98 mm{sup 2} (maximum field size on the Novalis Classic linac) at 100 cm SSD. The x-ray spectrum was determined from the MC data as well. The model provides an investigation into GATE'S capabilities and has the potential to be used as a research tool and an independent dose calculation engine for clinical treatment plans.

  20. Quantitative analysis of results of quality control tests in linear accelerators used in radiotherapy; Analise quantitativa dos resultados de testes de controle de qualidade em aceleradores lineares usados em radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Passaro, Bruno M.; Rodrigues, Laura N. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Videira, Heber S., E-mail: bruno.passaro@gmail.com [Universidade de Sao Paulo (HCFMRP/USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Hospital das Clinicas

    2013-04-15

    The aim of this study is to assess and analyze the stability of the calibration factor of three linear accelerators, as well as the other dosimetric parameters normally included in a program of quality control in radiotherapy. The average calibration factors of the accelerators for the period of approximately four years for the Clinac 600C and Clinac 6EX were (0.998±0.012) and (0.996±0.014), respectively. For the Clinac 2100CD 6 MV and 15 MV was (1.008±0.009) and (1.006±0.010), respectively, in a period of approximately four years. The data of the calibration factors were divided into four subgroups for a more detailed analysis of behavior over the years. Through statistical analysis of calibration factors, we found that for the 600C and Clinacs 2100CD, is an expected probability that more than 90% of cases the values are within acceptable ranges according to TG-142, while for the Clinac 6EX is expected around 85% since this had several exchanges of accelerator components. The values of TPR20,10 of three accelerators are practically constant and within acceptable limits according to the TG-142. It can be concluded that a detailed study of data from the calibration factor of the accelerators and TPR{sub 20},{sub 10} from a quantitative point of view, is extremely useful in a quality assurance program. (author)