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Sample records for sustained linear acceleration

  1. LINEAR ACCELERATOR

    Science.gov (United States)

    Christofilos, N.C.; Polk, I.J.

    1959-02-17

    Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

  2. Linear Accelerator (LINAC)

    Science.gov (United States)

    ... View full size with caption Related Articles and Media External Beam Therapy (EBT) Intensity-Modulated Radiation Therapy (IMRT) Image-guided Radiation Therapy (IGRT) Stereotactic Radiosurgery (SRS) and Stereotactic Body Radiotherapy (SBRT) Images related to Linear Accelerator Sponsored ...

  3. RF linear accelerators

    CERN Document Server

    Wangler, Thomas P

    2008-01-01

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

  4. Introduction to Microwave Linear [Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Whittum, David H

    1999-01-04

    The elements of microwave linear accelerators are introduced starting with the principles of acceleration and accelerating structures. Considerations for microwave structure modeling and design are developed from an elementary point of view. Basic elements of microwave electronics are described for application to the accelerator circuit and instrumentation. Concepts of beam physics are explored together with examples of common beamline instruments. Charged particle optics and lattice diagnostics are introduced. Considerations for fixed-target and colliding-beam experimentation are summarized.

  5. Cast dielectric composite linear accelerator

    Science.gov (United States)

    Sanders, David M [Livermore, CA; Sampayan, Stephen [Manteca, CA; Slenes, Kirk [Albuquerque, NM; Stoller, H M [Albuquerque, NM

    2009-11-10

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

  6. Introduction to RF linear accelerators

    CERN Document Server

    Pichoff, N

    2006-01-01

    After a short introduction to applications of RF linacs and their advantages and drawbacks as opposed to circular accelerators, the model of RF resonant cavities and their excitation by RF sources or beam is introduced. Then beam dynamics notions, essential to linacs, such as transit-time factor, synchronism, r.m.s. properties, matching and mismatching in linear or nonlinear forces, are presented.

  7. Seismic response of linear accelerators

    CERN Document Server

    Collette, C; Guinchard, M; Hauviller, C

    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 validated numerically on a regular lattice, taking the dynamic behavior of the machine alignment stage and the mechanical stabilization of the quadrupoles into account.

  8. Seismic response of linear accelerators

    Directory of Open Access Journals (Sweden)

    C. Collette

    2010-07-01

    Full Text Available 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 validated numerically on a regular lattice, taking the dynamic behavior of the machine alignment stage and the mechanical stabilization of the quadrupoles into account.

  9. Superconducting linear accelerator system for NSC

    Indian Academy of Sciences (India)

    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 ...

  10. 28th Linear Accelerator Conference

    CERN Document Server

    Facco, Alberto; McCausey, Amy; Schaa, Volker R W

    2017-01-01

    The 28th Linear Accelerator Conference, LINAC 16, to take place at the Kellogg Hotel and Conference Center in East Lansing, Michigan, on 25-30 September 2016. This conference is the main bi-yearly gathering for the world-wide community of linac specialists. It provides a unique opportunity to hear about the latest advances of projects and developments concerning hadron and lepton linacs, and their applications. In the tradition of previous LINAC conferences, plenary sessions including invited speakers are scheduled every day. Poster sessions will be held on Monday, Tuesday and Thursday afternoons. There will also be two special events on Sunday, 25 September 2016, namely a student poster session and an evening reception for registrants and their companions at the Kellogg Hotel and Conference Center. Participants are also warmly invited to join an outing to Lake Michigan and the beautiful surroundings on Wednesday afternoon, and to visit the Facility for Rare Isotope Beams on Friday afternoon, after the formal...

  11. 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

  12. Elementary principles of linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Loew, G.A.; Talman, R.

    1983-09-01

    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. Accelerating Dense Linear Algebra on the GPU

    DEFF Research Database (Denmark)

    Sørensen, Hans Henrik Brandenborg

    GPUs have already become an integral part of high performance scientific computing, since they offer dedicated parallel hardware that can potentially accelerate the execution of many scientific applications. In this talk, I will consider the automatic performance acceleration of dense vector...... and matrix-vector operations on GPUs. Such operations form the backbone of level 1 and level 2 routines in the Basic Linear Algebra Subroutines (BLAS) library and are therefore of great importance in many scientific applications. The target hardware is the most recent NVIDIA Tesla 20-series (Fermi...... architecture). Most of the techniques I discuss for accelerating dense linear algebra are applicable to memory-bound GPU algorithms in general....

  14. Superconducting linear accelerator system for NSC

    Indian Academy of Sciences (India)

    Superconducting linear accelerator system for NSC. 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 ...

  15. 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...

  16. 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)

  17. Resonance Control for Future Linear Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Schappert, Warren [Fermilab

    2017-05-01

    Many of the next generation of particle accelerators (LCLS II, PIP II) are designed for relatively low beam loading. Low beam loading requirement means the cavities can operate with narrow bandwidths, minimizing capital and base operational costs of the RF power system. With such narrow bandwidths, however, cavity detuning from microphonics or dynamic Lorentz Force Detuning becomes a significant factor, and in some cases can significantly increase both the acquisition cost and the operational cost of the machine. In addition to the efforts to passive environmental detuning reduction (microphonics) active resonance control for the SRF cavities for next generation linear machine will be required. State of the art in the field of the SRF Cavity active resonance control and the results from the recent efforts at FNAL will be presented in this talk.

  18. Magnetic repulsion of linear accelerator contaminates.

    Science.gov (United States)

    Butson, M J; Wong, T P; Law, A; Law, M; Mathur, J N; Metcalfe, P E

    1996-06-01

    Neodymium Iron Boron (NdFeB) rare earth permanent magnets have unique properties that enable them to fit easily onto the accessory mount of a clinical linear accelerator to partially sweep away electron contamination produced by the treatment head and block trays and thus increase skin sparing. Using such magnets the central axis entrance surface dose has been reduced by 11% for a 20 x 30 cm field size from 32% to 21% of maximum dose by the magnetic device. A reduction of 14% from 32% to 18% was seen for a 20 x 20 cm field size with a 6 mm perspex block tray positioned above the magnet. The magnetic device is light weight and thus clinically usable.

  19. Introduction to electrodynamics for microwave linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Whittum, D.H.

    1998-04-01

    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, [R/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.

  20. Radio frequency noise from clinical linear accelerators

    Science.gov (United States)

    Burke, B.; Lamey, M.; Rathee, S.; Murray, B.; Fallone, B. G.

    2009-04-01

    There is a great deal of interest in image-guided radiotherapy (IGRT), and to advance the state of IGRT, an integrated linear accelerator-magnetic resonance (linac-MR) system has been proposed. Knowledge of the radiofrequency (RF) emissions near a linac is important for the design of appropriate RF shielding to facilitate the successful integration of these two devices. The frequency spectra of both electric and magnetic fields of RF emission are measured using commercially available measurement probes near the treatment couch in three clinical linac vaults with distinct physical layouts. The magnitude spectrum of the RF power emitted from these three linacs is then estimated. The electric field spectrum was also measured at several distances from the linac modulator in order to assess the effects of variations in spatial location in the treatment vault. A large fraction of RF power is emitted at frequencies below 5 MHz. However, the measured RF power at the Larmor frequency (8.5 MHz) of the proposed 0.2 T MR in the linac-MR (0.4-14.6 µW m-2) is still large enough to cause artifacts in MR images. Magnetron-based linacs generally emit much larger RF power than klystron-based linacs. In the frequency range of 1-50 MHz, only slight variation in the measured electric field is observed as a function of measurement position. This study suggests that the RF emissions are strong enough to cause image artifacts in MRI systems.

  1. Multi-beam linear accelerator EVT

    Energy Technology Data Exchange (ETDEWEB)

    Teryaev, Vladimir E., E-mail: vladimir_teryaev@mail.ru [Omega-P, Inc., New Haven, CT 06510 (United States); Kazakov, Sergey Yu. [Fermilab, Batavia, IL 60510 (United States); Hirshfield, Jay L. [Omega-P, Inc., New Haven, CT 06510 (United States); Yale University, New Haven, CT 06511 (United States)

    2016-09-01

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

  2. Microdosimetry of photoneutrons around medical linear accelerators

    Science.gov (United States)

    Crossman, John S. P.

    Photoneutrons produced in the vicinity of medical linear accelerators for therapy, constitute a hazard which is difficult to assess and monitor. The aims of the project were to develop new techniques, using microdosimetry, which would be suitable for the improved quality control of pulsed photon beams and for the assessment of the associated photoneutron hazard in typical treatment facilities from the perspective of the patients and staff. The measurements of photoneutron yields and equivalent doses were obtained using activation analysis detectors around a 10 MV LINAC. To obtain adequate statistical precision, an optimum thickness of 2.5 cm of polyethylene was used that doubled the detector's sensitivity. This enabled the yields and spatial distribution of the low intensity field to be recorded. Photoneutron equivalent dose-rates of up to 0.104 Sv.h-1, or 0.1% of the useful photon dose- rates, were measured. In the literature, however, it was found that equivalent dose-rates could reach as high as 1 % of the useful photon treatment dose-rate for machines operating at X ray energies of ≥18 MV. Thus it is recommended that to uphold the principle of ALARA, such high energies (≥18 MV) should only be used when no lower energy machine is available. Microdosimetry with a tissue equivalent proportional counter (TEPC) microdosimeter, enabled the photoneutron contribution to the quality spectrum to be identified in the maze to the treatment room of the 10 MV LIN AC, and the photoneutrons there were assigned a radiation weighting factor of 20. The known problems concerning the rf interference and very high pulsed dose-rates inside the treatment room proved too severe to obtain meaningful results with the TEPC. The microdosimeter did however provide useful diagnostic information. Furthermore, a novel calibration technique for TEPC's was developed and an established one, the proton-edge method, was improved. A new approach was adopted to conduct microdosimetry in the

  3. Investigation of Bremsstrahlung spectra of 6 MV medical linear accelerator

    CERN Document Server

    Zhang Song Bai; Bao Shang Lian; Zhao Hong Bin; Han Shu Kui

    2003-01-01

    The energy spectra of the Bremsstrahlung X-rays from the 6 MV medical linear accelerator are measured by attenuation analysis of the transmission data. An universal Monte-Carlo program EGS4 is also used to calculate the Bremsstrahlung spectra of the 6 MV medical linear accelerator. The measurement results are in good agreement with the calculation results

  4. Beam dynamics simulation of a double pass proton linear accelerator

    Science.gov (United States)

    Hwang, Kilean; Qiang, Ji

    2017-04-01

    A recirculating superconducting linear accelerator with the advantage of both straight and circular accelerator has been demonstrated with relativistic electron beams. The acceleration concept of a recirculating proton beam was recently proposed [J. Qiang, Nucl. Instrum. Methods Phys. Res., Sect. A 795, 77 (2015, 10.1016/j.nima.2015.05.056)] and is currently under study. In order to further support the concept, the beam dynamics study on a recirculating proton linear accelerator has to be carried out. In this paper, we study the feasibility of a two-pass recirculating proton linear accelerator through the direct numerical beam dynamics design optimization and the start-to-end simulation. This study shows that the two-pass simultaneous focusing without particle losses is attainable including fully 3D space-charge effects through the entire accelerator system.

  5. Beam dynamics simulation of a double pass proton linear accelerator

    Directory of Open Access Journals (Sweden)

    Kilean Hwang

    2017-04-01

    Full Text Available A recirculating superconducting linear accelerator with the advantage of both straight and circular accelerator has been demonstrated with relativistic electron beams. The acceleration concept of a recirculating proton beam was recently proposed [J. Qiang, Nucl. Instrum. Methods Phys. Res., Sect. A 795, 77 (2015NIMAER0168-900210.1016/j.nima.2015.05.056] and is currently under study. In order to further support the concept, the beam dynamics study on a recirculating proton linear accelerator has to be carried out. In this paper, we study the feasibility of a two-pass recirculating proton linear accelerator through the direct numerical beam dynamics design optimization and the start-to-end simulation. This study shows that the two-pass simultaneous focusing without particle losses is attainable including fully 3D space-charge effects through the entire accelerator system.

  6. Test Stand for Linear Induction Accelerator Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Ong, M; DeHope, B; Griffin, K; Goerz, D; Kihara, R; Vogtlin, G; Zentler, J M; Scarpetti, R

    2003-06-03

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

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

    Science.gov (United States)

    Ikeda, Shota; Murata, Aki; Hayashizaki, Noriyosu

    2017-09-01

    The multi-beam acceleration method is an acceleration technique for low-energy high-intensity heavy ion beams, which involves accelerating multiple beams to decrease space charge effects, and then integrating these beams by a beam funneling system. At the Tokyo Institute of Technology a two beam IH-RFQ linear accelerator was developed using a two beam laser ion source with direct plasma injection scheme. This system accelerated a carbon ion beam with a current of 108 mA (54 mA/channel × 2) from 5 up to 60 keV/u. In order to demonstrate that a four-beam IH-RFQ linear accelerator is suitable for high-intensity heavy ion beam acceleration, we have been developing a four-beam prototype. A four-beam IH-RFQ linear accelerator consists of sixteen RFQ electrodes (4 × 4 set) with stem electrodes installed alternately on the upper and lower ridge electrodes. As a part of this development, we have designed a four-beam IH-RFQ linear accelerator using three dimensional electromagnetic simulation software and beam tracking simulation software. From these simulation results, we have designed the stem electrodes, the center plate and the side shells by evaluating the RF properties such as the resonance frequency, the power loss and the electric strength distribution between the RFQ electrodes.

  8. 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...... be the same, or nearly the same i.e. the accelerators must be beam-matched. During a period of nine months, eight Varian iX accelerators with 6 and 15 MV photon beams and 6-18 MeV electron beams (only four of the eight) were installed at our clinic. All accelerators fulfilled the vendor-defined "fine beam......-match" criteria, and a more extensive set of measurements was carried out during commissioning. The measured absorbed dose data for each accelerator were compared with the first accelerator, chosen as reference, and the TPS calculations. Two of the eight accelerators showed a larger discrepancy for the 15 MV beam...

  9. [The security system of SIEMENS digital linear accelerator].

    Science.gov (United States)

    Wang, Jianping

    2013-03-01

    The security system plays an important role to protect the safety of patients and equipment in radiotherapy. The principle and structure of three kinds of security system of the Siemens digital linear accelerator were analyzed with some examples.

  10. 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.

  11. KLYNAC: Compact linear accelerator with integrated power supply

    Energy Technology Data Exchange (ETDEWEB)

    Malyzhenkov, Alexander [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-16

    Accelerators and accelerator-based light sources have a wide range of applications in science, engineering technology and medicine. Today the scienti c community is working towards improving the quality of the accelerated beam and its parameters while trying to develop technology for reducing accelerator size. This work describes a design of a compact linear accelerator (linac) prototype, resonant Klynac device, which is a combined linear accelerator and its power supply - klystron. The intended purpose of a Klynac device is to provide a compact and inexpensive alternative to a conventional 1 to 6 MeV accelerator, which typically requires a separate RF source, an accelerator itself and all the associated hardware. Because the Klynac is a single structure, it has the potential to be much less sensitive to temperature variations than a system with separate klystron and linac. We start by introducing a simpli ed theoretical model for a Klynac device. We then demonstrate how a prototype is designed step-by-step using particle-in-cell simulation studies for mono- resonant and bi-resonant structures. Finally, we discuss design options from a stability point of view and required input power as well as behavior of competing modes for the actual built device.

  12. 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.

  13. Radio-frequency quadrupole resonator for linear accelerator

    Science.gov (United States)

    Moretti, A.

    1982-10-19

    An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles, with the construction being characterized by four elongated resonating rods within a cylinder with the rods being alternately shorted and open electrically to the shell at common ends of the rods to provide an LC parallel resonant circuit when activated by a magnetic field transverse to the longitudinal axis.

  14. SLC status and SLAC (Stanford Linear Accelerator Center) future plans

    Energy Technology Data Exchange (ETDEWEB)

    Richter, B.

    1989-08-01

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

  15. 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.

  16. Spin dynamics in storage rings and linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Irwin, J. [Stanford Univ., CA (United States)

    1994-12-01

    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.

  17. 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.

  18. 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.

  19. Demographic and Competitiveness Acceleration and Government Sustainable Advantage in Indonesia

    OpenAIRE

    Samosir, Omas Bulan; Rajagukguk, Wilson

    2017-01-01

    The objective of this research is to investigate the effects of demographic and competitiveness acceleration on sustainable advantage in government areas in Indonesia. The research is done at district level (kabupaten/kota) in Indonesia. The sustainable advantage variable is the gross domestic product (GDP), while the demographic and competitiveness acceleration variables are the dependency ratio growth rate, capital investment, percentage share of agriculture in the economy, and percentage o...

  20. 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...

  1. LINEAR LATTICE AND TRAJECTORY RECONSTRUCTION AND CORRECTION AT FAST LINEAR ACCELERATOR

    Energy Technology Data Exchange (ETDEWEB)

    Romanov, A. [Fermilab; Edstrom, D. [Fermilab; Halavanau, A. [Northern Illinois U.

    2017-07-16

    The low energy part of the FAST linear accelerator based on 1.3 GHz superconducting RF cavities was successfully commissioned [1]. During commissioning, beam based model dependent methods were used to correct linear lattice and trajectory. Lattice correction algorithm is based on analysis of beam shape from profile monitors and trajectory responses to dipole correctors. Trajectory responses to field gradient variations in quadrupoles and phase variations in superconducting RF cavities were used to correct bunch offsets in quadrupoles and accelerating cavities relative to their magnetic axes. Details of used methods and experimental results are presented.

  2. Rotational total skin electron irradiation with a linear accelerator.

    Science.gov (United States)

    Reynard, Eric P; Evans, Michael D C; Devic, Slobodan; Parker, William; Freeman, Carolyn R; Roberge, David; Podgorsak, Ervin B

    2008-11-03

    The rotational total skin electron irradiation (RTSEI) technique at our institution has undergone several developments over the past few years. Replacement of the formerly used linear accelerator has prompted many modifications to the previous technique. With the current technique, the patient is treated with a single large field while standing on a rotating platform, at a source-to-surface distance of 380 cm. The electron field is produced by a Varian 21EX linear accelerator using the commercially available 6 MeV high dose rate total skin electron mode, along with a custom-built flattening filter. Ionization chambers, radiochromic film, and MOSFET (metal oxide semiconductor field effect transistor) detectors have been used to determine the dosimetric properties of this technique. Measurements investigating the stationary beam properties, the effects of full rotation, and the dose distributions to a humanoid phantom are reported. The current treatment technique and dose regimen are also described.

  3. Detection of infrasound and linear acceleration in fishes.

    Science.gov (United States)

    Sand, O; Karlsen, H E

    2000-01-01

    Fishes have an acute sensitivity to extremely low-frequency linear acceleration, or infrasound, even down to below 1 Hz. The otolith organs are the sensory system responsible for this ability. The hydrodynamic noise generated by swimming fishes is mainly in the infrasound range, and may be important in courtship and prey predator interactions. Intense infrasound has a deterring effect on some species, and has a potential in acoustic barriers. We hypothesize that the pattern of ambient infrasound in the oceans may be used for orientation in migratory fishes, and that pelagic fishes may detect changes in the surface wave pattern associated with altered water depth and distant land formations. We suggest that the acute sensitivity to linear acceleration could be used for inertial guidance, and to detect the relative velocity of layered ocean currents. Sensitivity to infrasound may be a widespread ability among aquatic organisms, and has also been reported in cephalopods and crustaceans. PMID:11079418

  4. Dosimetric aspects of a 3.3-MV linear accelerator.

    Science.gov (United States)

    Steidley, K D; Rosen, C W

    1990-01-01

    Both the design considerations and the dosimetric properties of the Siemens Model 5800 linear accelerator are discussed. This unit is of such an energy (3.3 MV) as to imitate Cobalt-60 teletherapy depth doses. A linear relation of dmax to depth dose at low energies was found for various wave guides and targets. The energy of the unit can be characterized by its nominal accelerating potential of 2.70 MV, its d80 of 5.3 cm, its first half-value layer of 0.8 cm lead and the measured energy of the electron beam at 3.3 MeV. The following selected commissioning aspects are reported: central axis depth dose, relative output factors, beam profiles, wedge factors, virtual source position, back scatter factors, penumbra and build-up region.

  5. Finite element analyses of a linear-accelerator electron gun

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, M., E-mail: muniqbal.chep@pu.edu.pk, E-mail: muniqbal@ihep.ac.cn [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Wasy, A. [Department of Mechanical Engineering, Changwon National University, Changwon 641773 (Korea, Republic of); Islam, G. U. [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Zhou, Z. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2014-02-15

    Thermo-structural analyses of the Beijing Electron-Positron Collider (BEPCII) linear-accelerator, electron gun, were performed for the gun operating with the cathode at 1000 °C. The gun was modeled in computer aided three-dimensional interactive application for finite element analyses through ANSYS workbench. This was followed by simulations using the SLAC electron beam trajectory program EGUN for beam optics analyses. The simulations were compared with experimental results of the assembly to verify its beam parameters under the same boundary conditions. Simulation and test results were found to be in good agreement and hence confirmed the design parameters under the defined operating temperature. The gun is operating continuously since commissioning without any thermal induced failures for the BEPCII linear accelerator.

  6. Finite element analyses of a linear-accelerator electron gun

    Science.gov (United States)

    Iqbal, M.; Wasy, A.; Islam, G. U.; Zhou, Z.

    2014-02-01

    Thermo-structural analyses of the Beijing Electron-Positron Collider (BEPCII) linear-accelerator, electron gun, were performed for the gun operating with the cathode at 1000 °C. The gun was modeled in computer aided three-dimensional interactive application for finite element analyses through ANSYS workbench. This was followed by simulations using the SLAC electron beam trajectory program EGUN for beam optics analyses. The simulations were compared with experimental results of the assembly to verify its beam parameters under the same boundary conditions. Simulation and test results were found to be in good agreement and hence confirmed the design parameters under the defined operating temperature. The gun is operating continuously since commissioning without any thermal induced failures for the BEPCII linear accelerator.

  7. 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.

  8. 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.

  9. Transient effect in high intensity proton linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Senichev, Yu

    1993-09-01

    We study the possible mechanism of the separatrix destruction during the transient in the linear accelerator. This effect is due to the parametric resonance of the beam in the longitudinal plane caused by the perturbations of electromagnetic field. The magnitude of time-space perturbations of the electromagnetic field depends on the disperse feature of resonator and the beam intensity. In the paper we discuss how to avoid this effect or to decrease its influence.

  10. Quality assurance for stereotactic radiosurgery using linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Gotoh, Shinichi [Nagasaki Univ. (Japan). Hospital; Hayashi, Nobuyuki; Minami, Kazunori; Uchida, Takatoshi; Obata, Shiro

    1997-06-01

    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 {sup s}tar 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)

  11. Linear Programming Approach to Sustainable Management of ...

    African Journals Online (AJOL)

    A linear programming (LP) model was used to prescribe timber harvest in the management of even-aged Gmelina arborea plantations in Omo Forest Reserve, Southwestern, Nigeria. The plantations now being managed for timber production are to be exploited within fifteen years based on a 5-year harvesting period.

  12. 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)

  13. 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.

  14. Radio-Frequency Pulse Compression for Linear Accelerators.

    Science.gov (United States)

    Nantista, Christopher Dennis

    Recent efforts to develop plans for an electron -positron linear collider with center-of-mass energy approaching a TeV have highlighted the need for sources capable of delivering hundreds of megawatts of peak rf drive power at X-band frequencies. This need has driven work in the area of rf pulse compression, which enhances the peak power available from pulsed rf tubes by compressing their output pulses in time, accumulating the available energy into shorter pulses. The classic means of rf pulse compression for linear accelerators is SLED. This technique is described, and the problem it presents for multibunch acceleration explained. Other pulse compression schemes, capable of producing suitable output pulses are explored, both theoretically and experimentally, in particular Binary Pulse Compression and SLED-II. The merits of each are considered with regard to gain, efficiency, complexity, size and cost. The development of some novel system components, along with the theory behind their design, is also discussed. The need to minimize copper losses in long waveguide runs led to the use of the circular TE_{01} propagation mode in over-moded guide, requiring much attention to mechanisms of coupling power between modes. The construction and commissioning of complete, high-power pulse compression systems is reported on, as well as their use in the testing of X-band accelerating structures, which, along with the X-band klystrons used, were developed at SLAC in parallel with the pulse compression work. The focus of the dissertation is on SLED-II, the favored scheme in some current linear accelerator designs. In addition to our experimental results, practical implementation considerations and design improvements are presented. The work to date has led to detailed plans for SLED-II systems to be used in the Next Linear Collider Test Accelerator, now under construction at SLAC. The prototype of the upgraded system is near completion. Descriptions of various rf pulse

  15. Design of Precision Alignment of Compact Linear Colliders Accelerating Structures

    CERN Document Server

    Huopana, Jouni; Taborelli, Mauro

    2007-01-01

    This thesis evaluates different assembly methods for particle accelerator called Compact Linear Colliders(CLIC) accelerating components. This work focuses on the definition of a strategy and mechanical design for the assembly of four quadrants in radial and longitudinal direction. The study takes into account the constraints specified by the various aspects of the physics involved in the application of such accelerating structures. The possible deformations due to a kinematic or elastic assembly and its influence on the final accuracy are calculated. Also the work considers the effect of a moderate temperature rise due to the steady state heating during machine operation and other loads due to the function of the machine. Accelerating structures must be aligned around the beam axis with a transversal accuracy of +/-0.003 mm and longitudinal accuracy of +/-0.01 mm over the length of a single module. This requirement includes the accuracy of the parts to be manufactured and the precision of the assembly of the ...

  16. Linear particle accelerator with seal structure between electrodes and insulators

    Science.gov (United States)

    Broadhurst, John H.

    1989-01-01

    An electrostatic linear accelerator includes an electrode stack comprised of primary electrodes formed or Kovar and supported by annular glass insulators having the same thermal expansion rate as the electrodes. Each glass insulator is provided with a pair of fused-in Kovar ring inserts which are bonded to the electrodes. Each electrode is designed to define a concavo-convex particle trap so that secondary charged particles generated within the accelerated beam area cannot reach the inner surface of an insulator. Each insulator has a generated inner surface profile which is so configured that the electrical field at this surface contains no significant tangential component. A spark gap trigger assembly is provided, which energizes spark gaps protecting the electrodes affected by over voltage to prevent excessive energy dissipation in the electrode stack.

  17. Smartphone application for mechanical quality assurance of medical linear accelerators.

    Science.gov (United States)

    Kim, Hwiyoung; Lee, Hyunseok; Park, Jong In; Choi, Chang Heon; Park, So-Yeon; Kim, Hee Jung; Kim, Young Suk; Ye, Sung-Joon

    2017-06-07

    Mechanical quality assurance (QA) of medical linear accelerators consists of time-consuming and human-error-prone procedures. We developed a smartphone application system for mechanical QA. The system consists of two smartphones: one attached to a gantry for obtaining real-time information on the mechanical parameters of the medical linear accelerator, and another displaying real-time information via a Bluetooth connection with the former. Motion sensors embedded in the smartphone were used to measure gantry and collimator rotations. Images taken by the smartphone's high-resolution camera were processed to evaluate accuracies of jaw-positioning, crosshair centering and source-to-surface distance (SSD). The application was developed using Android software development kit and OpenCV library. The accuracy and precision of the system was validated against an optical rotation stage and digital calipers, prior to routine QA measurements of five medical linear accelerators. The system accuracy and precision in measuring angles and lengths were determined to be 0.05  ±  0.05° and 0.25  ±  0.14 mm, respectively. The mean absolute errors (MAEs) in QA measurements of gantry and collimator rotation were 0.05  ±  0.04° and 0.05  ±  0.04°, respectively. The MAE in QA measurements of light field was 0.39  ±  0.36 mm. The MAEs in QA measurements of crosshair centering and SSD were 0.40  ±  0.35 mm and 0.41  ±  0.32 mm, respectively. In conclusion, most routine mechanical QA procedures could be performed using the smartphone application system with improved precision and within a shorter time-frame, while eliminating potential human errors.

  18. Shielding for neutrons produced by medical linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Rebello, Wilson F.; Silva, Ademir X. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia Nuclear]. E-mail: rebello@ime.eb.br; ademir@con.ufrj.br

    2007-07-01

    The shielding system called Multileaf Shielding (MLS) was designed in Brazil to be used for protection patients, who undergo radiotherapy treatment, against undesired neutrons produced in the medical linear accelerator heads. During the conceiving of the MLS it was necessary to evaluate its efficiency. For that purpose, several simulations using the Monte Carlo N-particle radiation transport code, MCNP5, were made, in order to evaluate the response of the new shielding system. The results showed a significant neutron dose reduction after the inclusion of the MLS. This work aims to presenting these simulation results. (author)

  19. Retuning the DARHT Axis-II Linear Induction Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Carl August Jr. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Schulze, Martin E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carlson, Carl A. [National Security Technologies, LLC. (NSTec), Mercury, NV (United States); Frayer, Daniel K. [National Security Technologies, LLC. (NSTec), Mercury, NV (United States)

    2015-03-31

    The Dual-Axis Radiographic Hydrodynamic Test (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. The Axis-II 1.7-kA, 1600-ns beam pulse is transported through the LIA by the magnetic field from 91 solenoids as it is accelerated to ~16.5 MeV. The magnetic field produced by the solenoids and 80 steering dipole pairs for a given set of magnet currents is known as the “tune” of the accelerator [1]. From June, 2013 through September, 2014 a single tune was used. This tune was based on measurements of LIA element positions made over several years [2], and models of solenoidal fields derived from actual field measurements [3] [4]. Based on the focus scan technique, changing the tune of the accelerator and downstream transport had no effect on the beam emittance, to within the uncertainties of the measurement. Beam sizes appear to have been overestimated in all prior measurements because of the low magnification of the imaging system. This has resulted in overestimates of emittance by ~50%. The high magnification imaging should be repeated with the old tune for direct comparison with the new tune. High magnification imaging with the new accelerator tune should be repeated after retuning the downstream to produce a much more symmetric beam to reduce the uncertainty of this measurement. Thus, these results should be considered preliminary until we can effect a new tune to produce symmetric spots at our imaging station, for high magnification images.

  20. 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)

  1. Electron linear accelerator system for natural rubber vulcanization

    Science.gov (United States)

    Rimjaem, S.; Kongmon, E.; Rhodes, M. W.; Saisut, J.; Thongbai, C.

    2017-09-01

    Development of an electron accelerator system, beam diagnostic instruments, an irradiation apparatus and electron beam processing methodology for natural rubber vulcanization is underway at the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The project is carried out with the aims to improve the qualities of natural rubber products. The system consists of a DC thermionic electron gun, 5-cell standing-wave radio-frequency (RF) linear accelerator (linac) with side-coupling cavities and an electron beam irradiation apparatus. This system is used to produce electron beams with an adjustable energy between 0.5 and 4 MeV and a pulse current of 10-100 mA at a pulse repetition rate of 20-400 Hz. An average absorbed dose between 160 and 640 Gy is expected to be archived for 4 MeV electron beam when the accelerator is operated at 400 Hz. The research activities focus firstly on assembling of the accelerator system, study on accelerator properties and electron beam dynamic simulations. The resonant frequency of the RF linac in π/2 operating mode is 2996.82 MHz for the operating temperature of 35 °C. The beam dynamic simulations were conducted by using the code ASTRA. Simulation results suggest that electron beams with an average energy of 4.002 MeV can be obtained when the linac accelerating gradient is 41.7 MV/m. The rms transverse beam size and normalized rms transverse emittance at the linac exit are 0.91 mm and 10.48 π mm·mrad, respectively. This information can then be used as the input data for Monte Carlo simulations to estimate the electron beam penetration depth and dose distribution in the natural rubber latex. The study results from this research will be used to define optimal conditions for natural rubber vulcanization with different electron beam energies and doses. This is very useful for development of future practical industrial accelerator units.

  2. Linear accelerator accelerating module to suppress back-acceleration of field-emitted particles

    Energy Technology Data Exchange (ETDEWEB)

    Benson, Stephen V.; Marhauser, Frank; Douglas, David R.; Ament, Lucas J. P.

    2017-12-05

    A method for the suppression of upstream-directed field emission in RF accelerators. The method is not restricted to a certain number of cavity cells, but requires similar operating field levels in all cavities to efficiently annihilate the once accumulated energy. Such a field balance is desirable to minimize dynamic RF losses, but not necessarily achievable in reality depending on individual cavity performance, such as early Q.sub.0-drop or quench field. The method enables a significant energy reduction for upstream-directed electrons within a relatively short distance. As a result of the suppression of upstream-directed field emission, electrons will impact surfaces at rather low energies leading to reduction of dark current and less issues with heating and damage of accelerator components as well as radiation levels including neutron generation and thus radio-activation.

  3. Spatial organization of linear vestibuloocular reflexes of the rat: responses during horizontal and vertical linear acceleration.

    Science.gov (United States)

    Hess, B J; Dieringer, N

    1991-12-01

    1. The spatial properties of linear vestibuloocular reflexes (LVOR) were studied in pigmented rats in response to sinusoidal linear acceleration on a sled. The orientation of the animal on the sled was altered in 15 degrees steps over the range of 360 degrees. Horizontal, vertical, and torsional components of eye movements were recorded with the magnetic field search coil technique in complete darkness. Conjugacy of the two eyes was studied in the horizontal movement plane. 2. Acceleration along the optic axis of one eye (approximately 50 degrees lateral) induced maximal vertical responses in the ipsilateral eye and, at the same time, maximal torsional responses in the contralateral eye. These vertical and torsional responses of the LVOR coincide with those obtained when the respective coplanar vertical semicircular canals are stimulated. Such a congruence suggests a common reference frame for LVOR and angular vestibuloocular reflexes (AVOR), with the result that direct combination of signals indicating apparent and real head tilt is facilitated. 3. Transformations of vertical and torsional responses into head coordinates (pitch and roll) show that these movements are compensatory in direction for any combination of apparent head tilt in pitch and roll planes. 4. Gain (rotation of the eye/apparent rotation of the gravity direction) was approximately 0.3 at 0.1 Hz and decreased to approximately 0.1 at 1.0 Hz. Vertical responses tended to have a larger gain than torsional responses. Phase lag relative to peak acceleration increased from about -9 degrees to about -47 degrees over the same frequency range. 5. Vertical linear acceleration evoked only vertical eye movements at a frequency of 1.0 Hz. 6. Horizontal responses of both eyes were symmetric or asymmetric in amplitude and in-phase (conjugate) or out-of-phase (disconjugate) with respect to each other, depending on the direction of linear acceleration. Translation in the transverse direction evoked conjugate

  4. Commissioning measurements for photon beam data on three TrueBeam linear accelerators, and comparison with Trilogy and Clinac 2100 linear accelerators.

    Science.gov (United States)

    Beyer, Gloria P

    2013-01-07

    This study presents the beam data measurement results from the commissioning of three TrueBeam linear accelerators. An additional evaluation of the measured beam data within the TrueBeam linear accelerators contrasted with two other linear accelerators from the same manufacturer (i.e., Clinac and Trilogy) was performed to identify and evaluate any differences in the beam characteristics between the machines and to evaluate the possibility of beam matching for standard photon energies. We performed a comparison of commissioned photon beam data for two standard photon energies (6 MV and 15 MV) and one flattening filter-free ("FFF") photon energy (10 FFF) between three different TrueBeam linear accelerators. An analysis of the beam data was then performed to evaluate the reproducibility of the results and the possibility of "beam matching" between the TrueBeam linear accelerators. Additionally, the data from the TrueBeam linear accelerator was compared with comparable data obtained from one Clinac and one Trilogy linear accelerator models produced by the same manufacturer to evaluate the possibility of "beam matching" between the TrueBeam linear accelerators and the previous models. The energies evaluated between the linear accelerator models are the 6 MV for low energy and the 15 MV for high energy. PDD and output factor data showed less than 1% variation and profile data showed variations within 1% or 2 mm between the three TrueBeam linear accelerators. PDD and profile data between the TrueBeam, the Clinac, and Trilogy linear accelerators were almost identical (less than 1% variation). Small variations were observed in the shape of the profile for 15 MV at shallow depths (Photon beam data were found to be reproducible between different TrueBeam linear accelerators well within the accepted clinical tolerance of ± 2%. The results indicate reproducibility in the TrueBeam machine head construction and a potential for beam matching between these types of linear

  5. Smartphone application for mechanical quality assurance of medical linear accelerators

    Science.gov (United States)

    Kim, Hwiyoung; Lee, Hyunseok; In Park, Jong; Choi, Chang Heon; Park, So-Yeon; Kim, Hee Jung; Kim, Young Suk; Ye, Sung-Joon

    2017-06-01

    Mechanical quality assurance (QA) of medical linear accelerators consists of time-consuming and human-error-prone procedures. We developed a smartphone application system for mechanical QA. The system consists of two smartphones: one attached to a gantry for obtaining real-time information on the mechanical parameters of the medical linear accelerator, and another displaying real-time information via a Bluetooth connection with the former. Motion sensors embedded in the smartphone were used to measure gantry and collimator rotations. Images taken by the smartphone’s high-resolution camera were processed to evaluate accuracies of jaw-positioning, crosshair centering and source-to-surface distance (SSD). The application was developed using Android software development kit and OpenCV library. The accuracy and precision of the system was validated against an optical rotation stage and digital calipers, prior to routine QA measurements of five medical linear accelerators. The system accuracy and precision in measuring angles and lengths were determined to be 0.05  ±  0.05° and 0.25  ±  0.14 mm, respectively. The mean absolute errors (MAEs) in QA measurements of gantry and collimator rotation were 0.05  ±  0.04° and 0.05  ±  0.04°, respectively. The MAE in QA measurements of light field was 0.39  ±  0.36 mm. The MAEs in QA measurements of crosshair centering and SSD were 0.40  ±  0.35 mm and 0.41  ±  0.32 mm, respectively. In conclusion, most routine mechanical QA procedures could be performed using the smartphone application system with improved precision and within a shorter time-frame, while eliminating potential human errors.

  6. 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.

  7. Longitudinal Jitter Analysis of a Linear Accelerator Electron Gun

    Directory of Open Access Journals (Sweden)

    MingShan Liu

    2016-11-01

    Full Text Available We present measurements and analysis of the longitudinal timing jitter of a Beijing Electron Positron Collider (BEPCII linear accelerator electron gun. We simulated the longitudinal jitter effect of the gun using PARMELA to evaluate beam performance, including: beam profile, average energy, energy spread, and XY emittances. The maximum percentage difference of the beam parameters is calculated to be 100%, 13.27%, 42.24% and 65.01%, 86.81%, respectively. Due to this, the bunching efficiency is reduced to 54%. However, the longitudinal phase difference of the reference particle was 9.89°. The simulation results are in agreement with tests and are helpful to optimize the beam parameters by tuning the trigger timing of the gun during the bunching process.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. Sustained acceleration on perception of relative position and motion.

    Science.gov (United States)

    McKinley, R Andrew; Tripp, Lloyd D; Fullerton, Kathy L; Goodyear, Chuck

    2013-03-01

    Air-to-air refueling, formation flying, and projectile countermeasures all rely on a pilot's ability to be aware of his position and motion relative to another object. Eight subjects participated in the study, all members of the sustained acceleration stress panel at Wright-Patterson AFB, OH. The task consisted of the subject performing a two-dimensional join up task between a KC-135 tanker and an F-16. The objective was to guide the nose of the F-16 to the posterior end of the boom extended from the tanker, and hold this position for 2 s. If the F-16 went past the tanker, or misaligned with the tanker, it would be recorded as an error. These tasks were performed during four G(z) acceleration profiles starting from a baseline acceleration of 1.5 G(z). The plateaus were 3, 5, and 7 G(z). The final acceleration exposure was a simulated aerial combat maneuver (SACM). One subject was an outlier and therefore omitted from analysis. The mean capture time and percent error data were recorded and compared separately. There was a significant difference in error percentage change from baseline among the G(z) profiles, but not capture time. Mean errors were approximately 15% higher in the 7 G profile and 10% higher during the SACM. This experiment suggests that the ability to accurately perceive the motion of objects relative to other objects is impeded at acceleration levels of 7 G(z) or higher.

  13. Data acquisition workstation for Oak Ridge Electron Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Todd, J.H.; Rooney, B.D.; Spencer, R.R.; Weston, L.W.

    1991-01-01

    A new multiparameter data acquisition system for the Oak Ridge Electron Linear Accelerator (ORELA) was developed, fabricated and tested. This system uses an IBM PS/2 Model 80-111 personal computer and a data handler with a 2048-word buffer. The buffer can accept data at a rate exceeding one million events per second in bursts of 512 words of 64-bits length. The acquisition system, limited by software, can acquire data from 1, 2, or 3 digitizers; multiplex up to 4 detectors; read and control up to 16 scalers or registers; and output up to 32 DC logic lines that can be used to control external instrumentation. Software was developed for the OS/2 operating system, supporting multiparameter data storage for up to three million channels. Data can be collected in a background mode to make the computer available for other tasks while collecting data. The system also supports multiparameter biasing and can collect, crunch, and store data at rates of 30,000 events per second, each event containing up to 64-bits of information. A technical manual, ORNL/TM-11454, covering the use of the system has been published. 1 refs., 4 figs., 2 tabs.

  14. 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.

  15. 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.

  16. Multipurpose 5-MeV linear induction accelerator

    Energy Technology Data Exchange (ETDEWEB)

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

    1984-06-11

    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.

  17. 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.

  18. [Failure analysis of medical linear accelerator with reliability analyses].

    Science.gov (United States)

    Zakimi, Ken; Watanabe, Hiroyuki; Ishida, Hideki; Take, Toshio; Kato, Mitsuyoshi; Iwai, Tsugunori; Nitta, Masaru; Kato, Kyouichi; Nakazawa, Yasuo

    2014-12-01

    We analyzed a number of cases about the Linac troubles in our hospital and have examined the effect of preventive maintenance with Weibull analysis and exponential distribution from April 2001 to March 2012. The total failure by irradiation disabled was 1, 192. (1) Medical linear accelerator (MLC) system was 24.0%, (2) radiation dosimetry system 13.1%, and the (3) cooling-water system was 26.5%. It accounts for 63.6% of the total number of failures. Each parameter value m, which means the shape parameter, and the failure period expectancy of parts μ were (1) 1.21, 1.46/3.9, 3.8 years. 3.7, 3.6 years. (2) 2.84, 1.59/6.6, 4.3 years. 6.7, 5.9 years. (3) 5.12, 4.16/6.1, 8.5 years. 6.1, 8.5 years. Each shape parameter was m>1. It is believed that they are in the worn-out failure period. To prevent failure, MLC performance should be overhauled once every 3 years and a cooling unit should be overhauled once every 7 years. Preventive maintenance is useful in assessing the failure of radiation therapy equipment. In a radiation dosimetry part, you can make a preemptive move before the failure by changing the monitor's dosimeter board with a new part from the repairs stockpiled every 6 months for maintenance.

  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. Hamiltonian analysis for linearly acceleration-dependent Lagrangians

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Miguel, E-mail: miguelcruz02@uv.mx, E-mail: roussjgc@gmail.com, E-mail: molgado@fc.uaslp.mx, E-mail: efrojas@uv.mx; Gómez-Cortés, Rosario, E-mail: miguelcruz02@uv.mx, E-mail: roussjgc@gmail.com, E-mail: molgado@fc.uaslp.mx, E-mail: efrojas@uv.mx; Rojas, Efraín, E-mail: miguelcruz02@uv.mx, E-mail: roussjgc@gmail.com, E-mail: molgado@fc.uaslp.mx, E-mail: efrojas@uv.mx [Facultad de Física, Universidad Veracruzana, 91000 Xalapa, Veracruz, México (Mexico); Molgado, Alberto, E-mail: miguelcruz02@uv.mx, E-mail: roussjgc@gmail.com, E-mail: molgado@fc.uaslp.mx, E-mail: efrojas@uv.mx [Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, Avenida Salvador Nava S/N Zona Universitaria, CP 78290 San Luis Potosí, SLP, México (Mexico)

    2016-06-15

    We study the constrained Ostrogradski-Hamilton framework for the equations of motion provided by mechanical systems described by second-order derivative actions with a linear dependence in the accelerations. We stress out the peculiar features provided by the surface terms arising for this type of theories and we discuss some important properties for this kind of actions in order to pave the way for the construction of a well defined quantum counterpart by means of canonical methods. In particular, we analyse in detail the constraint structure for these theories and its relation to the inherent conserved quantities where the associated energies together with a Noether charge may be identified. The constraint structure is fully analyzed without the introduction of auxiliary variables, as proposed in recent works involving higher order Lagrangians. Finally, we also provide some examples where our approach is explicitly applied and emphasize the way in which our original arrangement results in propitious for the Hamiltonian formulation of covariant field theories.

  1. 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

  2. The dynamics of linear growth in distance, velocity and acceleration.

    Science.gov (United States)

    Gasser, T; Kneip, A; Binding, A; Prader, A; Molinari, L

    1991-01-01

    Growth of body, leg, trunk and arm length from birth to adulthood is studied in the subjects of the First Zürich Longitudinal Growth Study, using a recently developed technique, the 'structural average curve'. In this way truly longitudinal average curves are obtained for velocity, acceleration and distances, and various phases of growth are analysed not only graphically, but also by descriptive parameters in terms of timing, intensity and duration. These phases consist of the pubertal spurt (PS), the mid-growth spurt (MS) and growth in infancy. The overall pattern is the same in all variables studied: velocity drops sharply after birth, followed by a kink between 7 and 12 months, and a more gradual decrease until the MS, which peaks around 7 years. In girls the PS immediately follows the MS, while in boys a 'latency period' of approximately constant growth velocity precedes the PS, which occurs almost 2 years later, and is more intense than in girls. There are no appreciable sex differences in the MS, but the PS is later and more intense for boys, even when accounting for the smaller adult size of girls. When comparing linear variables the PS turns out to be earlier for the legs than for the trunk, whereas the trunk has an earlier MS. The trunk starts high in relative distance and in velocity after birth, whereas the legs have a high velocity throughout childhood. In adolescence the trunk again shows more intense growth. Surprisingly, the growth of the arms in many ways resembles more that of the trunk and not that of the legs.

  3. 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.

  4. 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.

  5. Design of cavities of a standing wave accelerating tube for a 6 MeV electron linear accelerator

    Directory of Open Access Journals (Sweden)

    S Zarei

    2017-08-01

    Full Text Available Side-coupled standing wave tubes in  mode are widely used in the low-energy electron linear accelerator, due to high accelerating gradient and low sensitivity to construction tolerances. The use of various simulation software for designing these kinds of tubes is very common nowadays. In this paper, SUPERFISH code and COMSOL are used for designing the accelerating and coupling cavities for a 6 MeV electron linear accelerator. Finite difference method in SUPERFISH code and Finite element method in COMSOL are used to solve the equations. Besides, dimension of accelerating and coupling cavities and also coupling iris dimension are optimized to achieve resonance frequency of 2.9985 MHz and coupling constant of 0.0112. Considering the results of this study and designing of the RF energy injection port subsequently, the construction of 6 MeV electron tube will be provided

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

    CERN Document Server

    Lazarev, N V

    2000-01-01

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

  7. Brain injury prediction: assessing the combined probability of concussion using linear and rotational head acceleration.

    Science.gov (United States)

    Rowson, Steven; Duma, Stefan M

    2013-05-01

    Recent research has suggested possible long term effects due to repetitive concussions, highlighting the importance of developing methods to accurately quantify concussion risk. This study introduces a new injury metric, the combined probability of concussion, which computes the overall risk of concussion based on the peak linear and rotational accelerations experienced by the head during impact. The combined probability of concussion is unique in that it determines the likelihood of sustaining a concussion for a given impact, regardless of whether the injury would be reported or not. The risk curve was derived from data collected from instrumented football players (63,011 impacts including 37 concussions), which was adjusted to account for the underreporting of concussion. The predictive capability of this new metric is compared to that of single biomechanical parameters. The capabilities of these parameters to accurately predict concussion incidence were evaluated using two separate datasets: the Head Impact Telemetry System (HITS) data and National Football League (NFL) data collected from impact reconstructions using dummies (58 impacts including 25 concussions). Receiver operating characteristic curves were generated, and all parameters were significantly better at predicting injury than random guessing. The combined probability of concussion had the greatest area under the curve for all datasets. In the HITS dataset, the combined probability of concussion and linear acceleration were significantly better predictors of concussion than rotational acceleration alone, but not different from each other. In the NFL dataset, there were no significant differences between parameters. The combined probability of concussion is a valuable method to assess concussion risk in a laboratory setting for evaluating product safety.

  8. 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

  9. Heavy ion linear accelerator for radiation damage studies of materials

    Energy Technology Data Exchange (ETDEWEB)

    Kutsaev, Sergey V.; Mustapha, Brahim; Ostroumov, Peter N.; Nolen, Jerry; Barcikowski, Albert; Pellin, Michael; Yacout, Abdellatif

    2017-03-01

    A new eXtreme MATerial (XMAT) research facility is being proposed at Argonne National Laboratory to enable rapid in situ mesoscale bulk analysis of ion radiation damage in advanced materials and nuclear fuels. This facility combines a new heavy-ion accelerator with the existing high-energy X-ray analysis capability of the Argonne Advanced Photon Source. The heavy-ion accelerator and target complex will enable experimenters to emulate the environment of a nuclear reactor making possible the study of fission fragment damage in materials. Material scientists will be able to use the measured material parameters to validate computer simulation codes and extrapolate the response of the material in a nuclear reactor environment. Utilizing a new heavy-ion accelerator will provide the appropriate energies and intensities to study these effects with beam intensities which allow experiments to run over hours or days instead of years. The XMAT facility will use a CW heavy-ion accelerator capable of providing beams of any stable isotope with adjustable energy up to 1.2 MeV/u for U-238(50+) and 1.7 MeV for protons. This energy is crucial to the design since it well mimics fission fragments that provide the major portion of the damage in nuclear fuels. The energy also allows damage to be created far from the surface of the material allowing bulk radiation damage effects to be investigated. The XMAT ion linac includes an electron cyclotron resonance ion source, a normal-conducting radio-frequency quadrupole and four normal-conducting multi-gap quarter-wave resonators operating at 60.625 MHz. This paper presents the 3D multi-physics design and analysis of the accelerating structures and beam dynamics studies of the linac.

  10. Heavy ion linear accelerator for radiation damage studies of materials

    Science.gov (United States)

    Kutsaev, Sergey V.; Mustapha, Brahim; Ostroumov, Peter N.; Nolen, Jerry; Barcikowski, Albert; Pellin, Michael; Yacout, Abdellatif

    2017-03-01

    A new eXtreme MATerial (XMAT) research facility is being proposed at Argonne National Laboratory to enable rapid in situ mesoscale bulk analysis of ion radiation damage in advanced materials and nuclear fuels. This facility combines a new heavy-ion accelerator with the existing high-energy X-ray analysis capability of the Argonne Advanced Photon Source. The heavy-ion accelerator and target complex will enable experimenters to emulate the environment of a nuclear reactor making possible the study of fission fragment damage in materials. Material scientists will be able to use the measured material parameters to validate computer simulation codes and extrapolate the response of the material in a nuclear reactor environment. Utilizing a new heavy-ion accelerator will provide the appropriate energies and intensities to study these effects with beam intensities which allow experiments to run over hours or days instead of years. The XMAT facility will use a CW heavy-ion accelerator capable of providing beams of any stable isotope with adjustable energy up to 1.2 MeV/u for 238U50+ and 1.7 MeV for protons. This energy is crucial to the design since it well mimics fission fragments that provide the major portion of the damage in nuclear fuels. The energy also allows damage to be created far from the surface of the material allowing bulk radiation damage effects to be investigated. The XMAT ion linac includes an electron cyclotron resonance ion source, a normal-conducting radio-frequency quadrupole and four normal-conducting multi-gap quarter-wave resonators operating at 60.625 MHz. This paper presents the 3D multi-physics design and analysis of the accelerating structures and beam dynamics studies of the linac.

  11. 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.

  12. Neuromuscular Control of Rapid Linear Accelerations in Fish

    Science.gov (United States)

    2016-06-22

    fish : Final Report Eric D. Tytell Department of Biology , Tufts University, eric.tytell@tufts.edu Abstract In this project, we measured muscle... important aspects of how rapid movements are controlled, but will have to be done using a negative stimulus such as a object accelerating toward the fish ...sunfish, Lepomis macrochirus. Animals with flexible bodies, like fishes , face a tradeoff for rapid movements. To produce high forces, they must

  13. Dual linear accelerator system for use in sterilization of medical disposable supplies

    Science.gov (United States)

    Sadat, Theo

    1991-05-01

    Accelerators can be used for sterilization or decontamination (medical disposables, food, plastics, hospital waste, etc.). Most of these accelerators are located in an industrial environment and must have a high availability. A dual accelerator system (composed of two accelerators) offers optimal flexibility and reliability. The main advantage of this system is "all-in all-out" because it does not need a turnover of products. Such a dual system, composed of two 10 MeV 20 kW linear accelerators (instead of one 40 kW linac), has been chosen by a Swedish company (Mölnlycke).

  14. Linear and angular head accelerations during heading of a soccer ball

    National Research Council Canada - National Science Library

    Naunheim, Rosanne S; Bayly, Philip V; Standeven, John; Neubauer, Jeremy S; Lewis, Larry M; Genin, Guy M

    2003-01-01

    .... To assess the severity of a single instance of heading a soccer ball, this study experimentally and theoretically evaluated the linear and angular accelerations experienced by the human head during...

  15. 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)

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

    Science.gov (United States)

    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.

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

    OpenAIRE

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

    2014-01-01

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

  18. 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/...

  19. Parameterization of photon beam dosimetry for a linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lebron, Sharon; Barraclough, Brendan [Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, Florida 32610-0385 and J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611 (United States); Lu, Bo; Yan, Guanghua; Kahler, Darren; Li, Jonathan G.; Liu, Chihray, E-mail: liucr@shands.ufl.edu [Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, Florida 32610-0385 (United States)

    2016-02-15

    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 modeled data, (3) the quality assurance process of a linear accelerator’s (Linac) beam characteristics, (4) the establishment of a standard data set for comparison with other data, etcetera. Parameterization of the photon beam dosimetry creates a data set that is portable and easy to implement for different applications such as those previously mentioned. The aim of this study is to develop methods to parameterize photon beam dosimetric quantities, including percentage depth doses (PDDs), profiles, and total scatter output factors (S{sub cp}). Methods: S{sub cp}, PDDs, and profiles for different field sizes, depths, and energies were measured for a Linac using a cylindrical 3D water scanning system. All data were smoothed for the analysis and profile data were also centered, symmetrized, and geometrically scaled. The S{sub cp} data were analyzed using an exponential function. The inverse square factor was removed from the PDD data before modeling and the data were subsequently analyzed using exponential functions. For profile modeling, one halfside of the profile was divided into three regions described by exponential, sigmoid, and Gaussian equations. All of the analytical functions are field size, energy, depth, and, in the case of profiles, scan direction specific. The model’s parameters were determined using the minimal amount of measured data necessary. The model’s accuracy was evaluated via the calculation of absolute differences between the measured (processed) and calculated data in low gradient regions and distance-to-agreement analysis in high gradient regions. Finally, the results of dosimetric quantities obtained by the fitted models for a different machine were also assessed. Results: All of the differences in the PDDs’ buildup and the

  20. Design and construction of cavity frequency measurement and tuning systems of traveling wave electron linear accelerator

    Directory of Open Access Journals (Sweden)

    S Ahmadiannamin

    2017-08-01

    Full Text Available The main purpose for designing and constructing electroradio frequency linear accelerators is to reach better beam quality with higher power and energy by lower RF power consumption. The main step for this purpose is doing research and development in the area of designing, constructing, measuring and tuning of accelerator RF cavities. Institute for Research in Fundamental Sciences (IPM linear accelerator projecta is the first Iranian project for construction of electrolinear accelerator. In this paper, a brief introduction to construction procedure has been given. Then, the measurement and tuning of a disk-loaded periodic structure before and after tuning was reported. In addition, the detailed design and measurement setup for electric field measurement by perturbation method was investigated  

  1. [The effect of irradiation using a linear accelerator on the dentognathic system of white rats].

    Science.gov (United States)

    Cai, J J

    1989-03-01

    The LMR-15c linear accelerator was used to irradiate the maxillofacial region of white rats. The results showed that when the irradiation dose reached 3,000 rad (TDF49), changes in pulpal tissue, periodontal tissue, parotid and submandibular gland, lymph nodes and oral mucosa began to take place and became severe as the times of irradiation and the cumulated doses increased. The body weight of rats had no obvious changes after irradiation, however, blood changes and during the recovery period showed that the injury of irradiation to immune function was obvious. The biological effects of X-rays, 60 Cobalt and linear accelerator were compared. The irradiation damage to the surface of oral tissues was milder in the latter, and no change could be found in jaw bones. It was suggested that the linear accelerator is the first choice to be selected for treatment of oral cancers.

  2. A compact linear accelerator based on a scalable microelectromechanical-system RF-structure

    Science.gov (United States)

    Persaud, A.; Ji, Q.; Feinberg, E.; Seidl, P. A.; Waldron, W. L.; Schenkel, T.; Lal, A.; Vinayakumar, K. B.; Ardanuc, S.; Hammer, D. A.

    2017-06-01

    A new approach for a compact radio-frequency (RF) accelerator structure is presented. The new accelerator architecture is based on the Multiple Electrostatic Quadrupole Array Linear Accelerator (MEQALAC) structure that was first developed in the 1980s. The MEQALAC utilized RF resonators producing the accelerating fields and providing for higher beam currents through parallel beamlets focused using arrays of electrostatic quadrupoles (ESQs). While the early work obtained ESQs with lateral dimensions on the order of a few centimeters, using a printed circuit board (PCB), we reduce the characteristic dimension to the millimeter regime, while massively scaling up the potential number of parallel beamlets. Using Microelectromechanical systems scalable fabrication approaches, we are working on further reducing the characteristic dimension to the sub-millimeter regime. The technology is based on RF-acceleration components and ESQs implemented in the PCB or silicon wafers where each beamlet passes through beam apertures in the wafer. The complete accelerator is then assembled by stacking these wafers. This approach has the potential for fast and inexpensive batch fabrication of the components and flexibility in system design for application specific beam energies and currents. For prototyping the accelerator architecture, the components have been fabricated using the PCB. In this paper, we present proof of concept results of the principal components using the PCB: RF acceleration and ESQ focusing. Ongoing developments on implementing components in silicon and scaling of the accelerator technology to high currents and beam energies are discussed.

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

    Energy Technology Data Exchange (ETDEWEB)

    Gene Golub; Kwok Ko

    2009-03-30

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

  4. 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.

  5. Design for simultaneous acceleration of stable and unstable beams in a superconducting heavy-ion linear accelerator for RISP

    Science.gov (United States)

    Kim, Jongwon; Son, Hyock-Jun; Park, Young-Ho

    2017-11-01

    The post-accelerator of isotope separation on-line (ISOL) system for rare isotope science project (RISP) is a superconducting linear accelerator (SC-linac) with a DC equivalent voltage of around 160 MV. An isotope beam extracted from the ISOL is in a charge state of 1+ and its charge state is increased to n+ by charge breeding with an electron beam ion source (EBIS). The charge breeding takes tens of ms and the pulse width of extracted beam from the EBIS is tens of μs, which operates at up to 30 Hz. Consequently a large portion of radio frequency (rf) time of the post SC-linac is unused. The post-linac is equipped also with an electron cyclotron resonance (ECR) ion source for stable ion acceleration. Thanks to the large phase acceptance of SC-linac, it is possible to accelerate simultaneously both stable and radioisotope ions with a similar charge to mass ratio by sharing rf time. This operation scheme is implemented for RISP with the addition of an electric chopper and magnetic kickers. The facility will be capable of providing the users of the ISOL and in-flight fragmentation (IF) systems with different beams simultaneously, which would help nuclear science users in obtaining a beam time as high-precision measurements often need long hours.

  6. Quantitative Approach to Failure Mode and Effect Analysis for Linear Accelerator Quality Assurance

    Energy Technology Data Exchange (ETDEWEB)

    O' Daniel, Jennifer C., E-mail: jennifer.odaniel@duke.edu; Yin, Fang-Fang

    2017-05-01

    Purpose: To determine clinic-specific linear accelerator quality assurance (QA) TG-142 test frequencies, to maximize physicist time efficiency and patient treatment quality. Methods and Materials: A novel quantitative approach to failure mode and effect analysis is proposed. Nine linear accelerator-years of QA records provided data on failure occurrence rates. The severity of test failure was modeled by introducing corresponding errors into head and neck intensity modulated radiation therapy treatment plans. The relative risk of daily linear accelerator QA was calculated as a function of frequency of test performance. Results: Although the failure severity was greatest for daily imaging QA (imaging vs treatment isocenter and imaging positioning/repositioning), the failure occurrence rate was greatest for output and laser testing. The composite ranking results suggest that performing output and lasers tests daily, imaging versus treatment isocenter and imaging positioning/repositioning tests weekly, and optical distance indicator and jaws versus light field tests biweekly would be acceptable for non-stereotactic radiosurgery/stereotactic body radiation therapy linear accelerators. Conclusions: Failure mode and effect analysis is a useful tool to determine the relative importance of QA tests from TG-142. Because there are practical time limitations on how many QA tests can be performed, this analysis highlights which tests are the most important and suggests the frequency of testing based on each test's risk priority number.

  7. 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).

  8. 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...

  9. Assessment of human exposure doses received by activation of medical linear accelerator components

    Science.gov (United States)

    Lee, D.-Y.; Kim, J.-H.; Park, E.-T.

    2017-08-01

    This study analyzes the radiation exposure dose that an operator can receive from radioactive components during maintenance or repair of a linear accelerator. This study further aims to evaluate radiological safety. Simulations are performed on 10 MV and 15 MV photon beams, which are the most frequently used high-energy beams in clinics. The simulation analyzes components in order of activity and the human exposure dose based on the amount of neutrons received. As a result, the neutron dose, radiation dose, and human exposure dose are ranked in order of target, primary collimator, flattening filter, multi-leaf collimator, and secondary collimator, where the minimum dose is 9.34E-07 mSv/h and the maximum is 1.71E-02 mSv/h. When applying the general dose limit (radiation worker 20 mSv/year, pubic 1 mSv/year) in accordance with the Nuclear Safety Act, all components of a linear accelerator are evaluated as below the threshold value. Therefore, the results suggest that there is no serious safety issue for operators in maintaining and repairing a linear accelerator. Nevertheless, if an operator recognizes an exposure from the components of a linear accelerator during operation and considers the operating time and shielding against external exposure, exposure of the operator is expected to be minimized.

  10. Cobalt-60 Machines and Medical Linear Accelerators: Competing Technologies for External Beam Radiotherapy.

    Science.gov (United States)

    Healy, B J; van der Merwe, D; Christaki, K E; Meghzifene, A

    2017-02-01

    Medical linear accelerators (linacs) and cobalt-60 machines are both mature technologies for external beam radiotherapy. A comparison is made between these two technologies in terms of infrastructure and maintenance, dosimetry, shielding requirements, staffing, costs, security, patient throughput and clinical use. Infrastructure and maintenance are more demanding for linacs due to the complex electric componentry. In dosimetry, a higher beam energy, modulated dose rate and smaller focal spot size mean that it is easier to create an optimised treatment with a linac for conformal dose coverage of the tumour while sparing healthy organs at risk. In shielding, the requirements for a concrete bunker are similar for cobalt-60 machines and linacs but extra shielding and protection from neutrons are required for linacs. Staffing levels can be higher for linacs and more staff training is required for linacs. Life cycle costs are higher for linacs, especially multi-energy linacs. Security is more complex for cobalt-60 machines because of the high activity radioactive source. Patient throughput can be affected by source decay for cobalt-60 machines but poor maintenance and breakdowns can severely affect patient throughput for linacs. In clinical use, more complex treatment techniques are easier to achieve with linacs, and the availability of electron beams on high-energy linacs can be useful for certain treatments. In summary, there is no simple answer to the question of the choice of either cobalt-60 machines or linacs for radiotherapy in low- and middle-income countries. In fact a radiotherapy department with a combination of technologies, including orthovoltage X-ray units, may be an option. Local needs, conditions and resources will have to be factored into any decision on technology taking into account the characteristics of both forms of teletherapy, with the primary goal being the sustainability of the radiotherapy service over the useful lifetime of the equipment

  11. 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,...

  12. Wakefield damping in a pair of X-band accelerators for linear colliders

    Directory of Open Access Journals (Sweden)

    Roger M. Jones

    2006-10-01

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

  13. Non-linear response of a liquid bridge to a sinusoidal acceleration under microgravity

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, I.; Perales, J.M.; Meseguer, J. [Universidad Politecnica de Madrid, IDR/UPM, E.T.S.I. Aeronauticos, Madrid (Spain)

    2004-12-01

    An experiment was performed aboard a sounding rocket on a long cylindrical liquid bridge, aiming at discerning the real transfer function of this liquid configuration to small acceleration loads, quantified by the liquid free-surface deformation divided by the axially imposed acceleration. The results were, however, in great discrepancy with theoretical predictions, showing asymmetric jumps of high amplitude in the evolution of the radial deformation of the liquid bridge, instead of a symmetric sinusoidal radial deformation (axisymmetry was preserved). It has been found now that a non-linear dynamic model perfectly explains this unexpected behaviour. (orig.)

  14. Estimates of emittance dilution and stability in high-energy linear accelerators

    Directory of Open Access Journals (Sweden)

    T. O. Raubenheimer

    2000-12-01

    Full Text Available In this paper, we present a series of analytic expressions to predict the beam dynamics in a long linear accelerator. These expressions can be used to model the linac optics, calculate the magnitude of the wakefields, estimate the emittance dilution due to misaligned accelerator components, and estimate the stability and jitter limitations. The analytic expressions are based on the results of simple physics models and are useful to understand the parameter sensitivities. They are also useful when using simple codes or spreadsheets to optimize a linac system.

  15. Accelerated complete-linearization method for calculating NLTE model stellar atmospheres

    Science.gov (United States)

    Hubeny, I.; Lanz, T.

    1992-01-01

    Two approaches to accelerating the method of complete linearization for calculating NLTE model stellar atmospheres are suggested. The first one, the so-called Kantorovich variant of the Newton-Raphson method, consists of keeping the Jacobi matrix of the system fixed, which allows us to calculate the costly matrix inversions only a few times and then keep them fixed during the subsequent computations. The second method is an application of the Ng acceleration. Both methods are extremely easy to implement with any model atmosphere code based on complete linearization. It is demonstrated that both methods, and especially their combination, yield a rapidly and globally convergent algorithm, which takes 2 to 5 times less computer time, depending on the model at hand and the required accuracy, than the ordinary complete linearization. Generally, the time gain is more significant for more complicated models. The methods were tested for a broad range of atmospheric parameters, and in all cases they exhibited similar behavior. Ng acceleration applied on the Kantorovich variant thus offers a significant improvement of the standard complete-linearization method, and may now be used for calculating relatively involved NLTE model stellar atmospheres.

  16. 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

    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

  17. Design of the Compact Linear Collider main linac accelerating structure made from two halves

    Directory of Open Access Journals (Sweden)

    Hao Zha

    2017-04-01

    Full Text Available Milling on two longitudinally split halves is one method to manufacture accelerating structures. This method is simple and allows one to avoid electromagnetic fields at bonding joints, making it attractive in manufacturing high-gradient accelerating structures. An X-band structure design with strong wakefield damping based on this manufacturing approach is studied in this work as an alternative design for the Compact Linear Collider (CLIC main linac accelerating structures. The geometry of the structure is optimized to greatly reduce the surface fields, improve the efficiency, and suppress the wakefield. This structure features the baseline design of the CLIC main linac with additional advantages. This study may serve as a reference for designing other high frequency-band corrugated structures.

  18. Fast frequency-tuning of superconducting resonant rf cavities for heavy ion linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Peebles, Jr., Peyton Z.

    1971-12-01

    Superconducting resonant radio frequency (RF) cavities which utilize helices for producing ''slow'' wave velocities are prime candidates for creating the large accelerating electric fields needed in linear heavy ion accelerators. Because such structures are subject to mechanical vibrations, these vibrations may cause fast shifts in the cavity resonance, frequency. The result of such shifts is to cause undesirable phase modulation of the accelerating field. This report describes results of a study of an all-electronic method of fast tuning of the cavity to compensate for the vibration. Two types of control are discussed. The first employs only two electrical entrance points (ports) to the cavity. It is mechanically simpler than the second type, which uses three ports, but suffers some undesirable features not present in the three-port method.

  19. 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.

  20. 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.

  1. A study on the calculation of the shielding wall thickness in medical linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Yeon [Dept. of Radiation Oncology, Dongnam Ins. of Radiological and Medical Science, Busan (Korea, Republic of); Park, Eun Tae [Dept. of Radiation Oncology, Inje University Busan Paik Hospital, Busan (Korea, Republic of); Kim, Jung Hoon [Dept. of Radiological science, college of health sciences, Catholic University of Pusan, Busan (Korea, Republic of)

    2017-06-15

    The purpose of this study is to calculate the thickness of shielding for concrete which is mainly used for radiation shielding and study of the walls constructed to shield medical linear accelerator. The optimal shielding thickness was calculated using MCNPX(Ver.2.5.0) for 10 MV of photon beam energy generated by linear accelerator. As a result, the TVL for photon shielding was formed at 50⁓100 cm for pure concrete and concrete with Boron+polyethylene at 80⁓100 cm. The neutron shielding was calculated 100⁓140 cm for pure concrete and concrete with Boron+polyethylene at 90⁓100 cm. Based on this study, the concrete is considered to be most efficient method of using steel plates and adding Boron+polyethylene th the concrete.

  2. 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...... model checking (BMC) [Biere, Cimatti,Zhu, 1999] to CNF requires a blowup in either the formula size (worst-case exponential) or in the number of propositional variables (linear, thus yielding a worst-case exponential blow-up of the search space). We demonstrate that acceleration techniques like....... Despite the more expressive input language, the performance of our prototype implementation comes surprisingly close to that of state-of-the-art CNF-SAT engines like ZChaff [Moskewicz e.a., 2001]. First experiments with bounded model-construction problems show that the overhead in the satisfiability...

  3. Design of Linear Accelerator (LINAC) tanks for proton therapy via Particle Swarm Optimization (PSO) and Genetic Algorithm (GA) approaches

    Energy Technology Data Exchange (ETDEWEB)

    Castellano, T.; De Palma, L.; Laneve, D.; Strippoli, V.; Cuccovilllo, A.; Prudenzano, F. [Electrical and Information Engineering Department (DEI), Polytechnic Institute of Bari, 4 Orabona Street, CAP 70125, Bari, (Italy); Dimiccoli, V.; Losito, O.; Prisco, R. [ITEL Telecomunicazioni, 39 Labriola Street, CAP 70037, Ruvo di Puglia, Bari, (Italy)

    2015-07-01

    A homemade computer code for designing a Side- Coupled Linear Accelerator (SCL) is written. It integrates a simplified model of SCL tanks with the Particle Swarm Optimization (PSO) algorithm. The computer code main aim is to obtain useful guidelines for the design of Linear Accelerator (LINAC) resonant cavities. The design procedure, assisted via the aforesaid approach seems very promising, allowing future improvements towards the optimization of actual accelerating geometries. (authors)

  4. 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....

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

    Energy Technology Data Exchange (ETDEWEB)

    Lourenco, M.J.M.; Silva, F.C.A. da [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)]. E-mails: manuel@ird.gov.br; dasilva@ird.gov.br

    2002-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Trombik Peter

    2015-01-01

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

  7. 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.

  8. Laser-Induced Linear-Field Particle Acceleration in Free Space.

    Science.gov (United States)

    Wong, Liang Jie; Hong, Kyung-Han; Carbajo, Sergio; Fallahi, Arya; Piot, Philippe; Soljačić, Marin; Joannopoulos, John D; Kärtner, Franz X; Kaminer, Ido

    2017-09-11

    Linear-field particle acceleration in free space (which is distinct from geometries like the linac that requires components in the vicinity of the particle) has been studied for over 20 years, and its ability to eventually produce high-quality, high energy multi-particle bunches has remained a subject of great interest. Arguments can certainly be made that linear-field particle acceleration in free space is very doubtful given that first-order electron-photon interactions are forbidden in free space. Nevertheless, we chose to develop an accurate and truly predictive theoretical formalism to explore this remote possibility when intense, few-cycle electromagnetic pulses are used in a computational experiment. The formalism includes exact treatment of Maxwell's equations and exact treatment of the interaction among the multiple individual particles at near and far field. Several surprising results emerge. We find that electrons interacting with intense laser pulses in free space are capable of gaining substantial amounts of energy that scale linearly with the field amplitude. For example, 30 keV electrons (2.5% energy spread) are accelerated to 61 MeV (0.5% spread) and to 205 MeV (0.25% spread) using 250 mJ and 2.5 J lasers respectively. These findings carry important implications for our understanding of ultrafast electron-photon interactions in strong fields.

  9. Application of International Linear Collider superconducting cavities for acceleration of protons

    Directory of Open Access Journals (Sweden)

    P. N. Ostroumov

    2007-12-01

    Full Text Available Beam acceleration in the International Linear Collider (ILC will be provided by 9-cell 1300 MHz superconducting (SC cavities. The cavities are designed for effective acceleration of charged particles moving with the speed of light and are operated on π-mode to provide a maximum accelerating gradient. A significant research and development effort has been devoted to develop ILC SC technology and its rf system which resulted in excellent performance of ILC cavities. Therefore, the proposed 8-GeV proton driver in Fermilab is based on ILC cavities above ∼1.2  GeV. The efficiency of proton beam acceleration by ILC cavities drops fast for lower velocities and it was proposed to develop squeezed ILC-type (S-ILC cavities operating at 1300 MHz and designed for β_{G}=0.81, geometrical beta, to accelerate protons or H^{-} from ∼420  MeV to 1.2 GeV. This paper discusses the possibility of avoiding the development of new β_{G}=0.81 cavities by operating ILC cavities on 8/9π-mode of standing wave oscillations.

  10. Cosmic-ray acceleration in supernova remnants: non-linear theory revised

    Energy Technology Data Exchange (ETDEWEB)

    Caprioli, Damiano, E-mail: caprioli@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, 4 Ivy Ln. — Peyton Hall, Princeton, NJ 08544 (United States)

    2012-07-01

    A rapidly growing amount of evidences, mostly coming from the recent gamma-ray observations of Galactic supernova remnants (SNRs), is seriously challenging our understanding of how particles are accelerated at fast shocks. The cosmic-ray (CR) spectra required to account for the observed phenomenology are in fact as steep as E{sup −2.2}–E{sup −2.4}, i.e., steeper than the test-particle prediction of first-order Fermi acceleration, and significantly steeper than what expected in a more refined non-linear theory of diffusive shock acceleration. By accounting for the dynamical back-reaction of the non-thermal particles, such a theory in fact predicts that the more efficient the particle acceleration, the flatter the CR spectrum. In this work we put forward a self-consistent scenario in which the account for the magnetic field amplification induced by CR streaming produces the conditions for reversing such a trend, allowing — at the same time — for rather steep spectra and CR acceleration efficiencies (about 20%) consistent with the hypothesis that SNRs are the sources of Galactic CRs. In particular, we quantitatively work out the details of instantaneous and cumulative CR spectra during the evolution of a typical SNR, also stressing the implications of the observed levels of magnetization on both the expected maximum energy and the predicted CR acceleration efficiency. The latter naturally turns out to saturate around 10-30%, almost independently of the fraction of particles injected into the acceleration process as long as this fraction is larger than about 10{sup −4}.

  11. Sustainable Energy in Remote Indonesian Grids. Accelerating Project Development

    Energy Technology Data Exchange (ETDEWEB)

    Hirsch, Brian [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Burman, Kari [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Davidson, Carolyn [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Elchinger, Michael [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hardison, R. [Winrock International, Little Rock, AR (United States); Karsiwulan, D. [Winrock International, Little Rock, AR (United States); Castermans, B. [Winrock International, Little Rock, AR (United States)

    2015-06-30

    Sustainable Energy for Remote Indonesian Grids (SERIG) is a U.S. Department of Energy (DOE) funded initiative to support Indonesia’s efforts to develop clean energy and increase access to electricity in remote locations throughout the country. With DOE support, the SERIG implementation team consists of the National Renewable Energy Laboratory (NREL) and Winrock International’s Jakarta, Indonesia office. Through technical assistance that includes techno-economic feasibility evaluation for selected projects, government-to-government coordination, infrastructure assessment, stakeholder outreach, and policy analysis, SERIG seeks to provide opportunities for individual project development and a collective framework for national replication office.

  12. 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.

  13. Ion-hose instability in a long-pulse linear induction accelerator

    Directory of Open Access Journals (Sweden)

    Thomas C. Genoni

    2003-03-01

    Full Text Available The ion-hose instability is a transverse electrostatic instability which occurs on electron beams in the presence of a low-density ion channel. It is a phenomenon quite similar to the interaction between electron clouds and proton or positron beams in high-energy accelerators and storage rings. In the DARHT-2 accelerator, the 2-kA, 2-μs beam pulse produces an ion channel through impact ionization of the residual background gas (10^{-7}–10^{-6}   torr. A calculation of the linear growth by Briggs indicates that the instability could be strong enough to affect the radiographic application of DARHT, which requires that transverse oscillations be small compared to the beam radius. We present semianalytical theory and 3D particle-in-cell simulations (using the Lsp code of the linear and nonlinear growth of the instability, including the effects of the temporal change in the ion density and spatially decreasing beam radius. We find that the number of e-foldings experienced by a given beam slice is given approximately by an analytic expression using the local channel density at the beam slice. Hence, in the linear regime, the number of e-foldings increases linearly from head to tail of the beam pulse since it is proportional to the ion density. We also find that growth is strongly suppressed by nonlinear effects at relatively small oscillation amplitudes of the electron beam. This is because the ion oscillation amplitude is several times larger than that of the beam, allowing nonlinear effects to come into play. An analogous effect has recently been noted in electron-proton instabilities in high-energy accelerators and storage rings. For DARHT-2 parameters, we find that a pressure of ≤1.5×10^{-7}   torr is needed to keep the transverse beam oscillation amplitude less than about 20% of the rms beam radius.

  14. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Raubenheimer, Tor O. [Stanford Univ., CA (United States)

    1991-11-01

    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.

  16. Low-level RF signal processing for the Next Linear Collider Test Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Holmes, S.; Ziomek, C.; Adolphsen, C. [and others

    1997-05-12

    In the X-band accelerator system for the Next Linear Collider Test Accelerator (NLCTA), the Low Level RF (LLRF) drive system must be very phase stable, but concurrently, be very phase agile. Phase agility is needed to make the Stanford Linear Doubler (SLED) power multiplier systems Energy work and to shape the RF waveforms to compensate beam loading in the accelerator sections. Similarly, precision fast phase and amplitude monitors are required to view, track, and feed back on RF signals at various locations throughout the system. The LLRF is composed of several subsystems: the RF Reference System generates and distributes a reference 11.424 GHz signal to all of the RF stations, the Signal Processing Chassis creates the RF waveforms with the appropriate phase modulation, and the Phase Detector Assembly measures the amplitude and phase of monitor3ed RF signals. The LLRF is run via VXI instrumentation. These instruments are controlled using HP VEE graphical programming software. Programs have been developed to shape the RF waveform, calibrate the phase modulators and demodulators, and display the measured waveforms. This paper describes these and other components of the LLRF system.

  17. The International Linear Collider Technical Design Report - Volume 3.I: Accelerator \\& in the Technical Design Phase

    Energy Technology Data Exchange (ETDEWEB)

    Adolphsen, Chris [SLAC National Accelerator Lab., Menlo Park, CA (United States); et al.

    2013-06-26

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Adolphsen, Chris [SLAC National Accelerator Lab., Menlo Park, CA (United States); et al.

    2013-06-26

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

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

    CERN Document Server

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

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Carl Ekdahl

    2011-12-01

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

  1. 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.

  2. Assessing Risk in Costing High-energy Accelerators: from Existing Projects to the Future Linear Collider

    CERN Document Server

    Lebrun, Philippe

    2010-01-01

    High-energy accelerators are large projects funded by public money, developed over the years and constructed via major industrial contracts both in advanced technology and in more conventional domains such as civil engineering and infrastructure, for which they often constitute one-of markets. Assessing their cost, as well as the risk and uncertainty associated with this assessment is therefore an essential part of project preparation and a justified requirement by the funding agencies. Stemming from the experience with large circular colliders at CERN, LEP and LHC, as well as with the Main Injector, the Tevatron Collider Experiments and Accelerator Upgrades, and the NOvA Experiment at Fermilab, we discuss sources of cost variance and derive cost risk assessment methods applicable to the future linear collider, through its two technical approaches for ILC and CLIC. We also address disparities in cost risk assessment imposed by regional differences in regulations, procedures and practices.

  3. 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.

  4. A single-source photon source model of a linear accelerator for Monte Carlo dose calculation.

    Directory of Open Access Journals (Sweden)

    Obioma Nwankwo

    Full Text Available To introduce a new method of deriving a virtual source model (VSM of a linear accelerator photon beam from a phase space file (PSF for Monte Carlo (MC dose calculation.A PSF of a 6 MV photon beam was generated by simulating the interactions of primary electrons with the relevant geometries of a Synergy linear accelerator (Elekta AB, Stockholm, Sweden and recording the particles that reach a plane 16 cm downstream the electron source. Probability distribution functions (PDFs for particle positions and energies were derived from the analysis of the PSF. These PDFs were implemented in the VSM using inverse transform sampling. To model particle directions, the phase space plane was divided into a regular square grid. Each element of the grid corresponds to an area of 1 mm2 in the phase space plane. The average direction cosines, Pearson correlation coefficient (PCC between photon energies and their direction cosines, as well as the PCC between the direction cosines were calculated for each grid element. Weighted polynomial surfaces were then fitted to these 2D data. The weights are used to correct for heteroscedasticity across the phase space bins. The directions of the particles created by the VSM were calculated from these fitted functions. The VSM was validated against the PSF by comparing the doses calculated by the two methods for different square field sizes. The comparisons were performed with profile and gamma analyses.The doses calculated with the PSF and VSM agree to within 3% /1 mm (>95% pixel pass rate for the evaluated fields.A new method of deriving a virtual photon source model of a linear accelerator from a PSF file for MC dose calculation was developed. Validation results show that the doses calculated with the VSM and the PSF agree to within 3% /1 mm.

  5. A single-source photon source model of a linear accelerator for Monte Carlo dose calculation.

    Science.gov (United States)

    Nwankwo, Obioma; Glatting, Gerhard; Wenz, Frederik; Fleckenstein, Jens

    2017-01-01

    To introduce a new method of deriving a virtual source model (VSM) of a linear accelerator photon beam from a phase space file (PSF) for Monte Carlo (MC) dose calculation. A PSF of a 6 MV photon beam was generated by simulating the interactions of primary electrons with the relevant geometries of a Synergy linear accelerator (Elekta AB, Stockholm, Sweden) and recording the particles that reach a plane 16 cm downstream the electron source. Probability distribution functions (PDFs) for particle positions and energies were derived from the analysis of the PSF. These PDFs were implemented in the VSM using inverse transform sampling. To model particle directions, the phase space plane was divided into a regular square grid. Each element of the grid corresponds to an area of 1 mm2 in the phase space plane. The average direction cosines, Pearson correlation coefficient (PCC) between photon energies and their direction cosines, as well as the PCC between the direction cosines were calculated for each grid element. Weighted polynomial surfaces were then fitted to these 2D data. The weights are used to correct for heteroscedasticity across the phase space bins. The directions of the particles created by the VSM were calculated from these fitted functions. The VSM was validated against the PSF by comparing the doses calculated by the two methods for different square field sizes. The comparisons were performed with profile and gamma analyses. The doses calculated with the PSF and VSM agree to within 3% /1 mm (>95% pixel pass rate) for the evaluated fields. A new method of deriving a virtual photon source model of a linear accelerator from a PSF file for MC dose calculation was developed. Validation results show that the doses calculated with the VSM and the PSF agree to within 3% /1 mm.

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

    Directory of Open Access Journals (Sweden)

    Ricardo Aparecido Olivo

    2015-06-01

    Full Text Available Irradiation of blood components with ionizing radiation generated by a specific device is recommended to prevent transfusion-associated graft-versus-host disease. However, a lin- ear accelerator can also be used in the absence of such a device, which is the case of the blood bank facility studied herein. In order to evaluate the quality of the irradiated packed red blood cells, this study aimed to determine whether the procedure currently employed in the facility is effective in inhibiting the proliferation of T lymphocytes without damaging blood components. The proliferation of T lymphocytes, plasma potassium levels, and the degree of hemolysis were evaluated and compared to blood bags that received no irradiation. Packed red blood cell bags were irradiated at a dose of 25 Gy in a linear accelerator. For this purpose, a container was designed to hold the bags and to ensure even distribution of irradiation as evaluated by computed tomography and dose-volume histogram. Irradiation was observed to inhibit the proliferation of lymphocytes. The percentage of hemolysis in irradiated bags was slightly higher than in non-irradiated bags (p-value >0.05, but it was always less than 0.4% of the red cell mass. Although potassium increased in both groups, it was more pronounced in irradiated red blood cells, especially after seven days of storage, with a linear increase over storage time. The findings showed that, at an appropriate dosage and under validated conditions, the irradiation of packed red blood cells in a linear accelerator is effective, inhibiting lymphocyte proliferation but without compromising the viability of the red cells.

  7. Obtaining the Wakefield Due to Cell-to-Cell Misalignments in a Linear Accelerator Structure

    OpenAIRE

    Bane, Karl L. F.; Li, Zenghai

    2001-01-01

    A linear accelerator structure, such as will be used in the linacs of the JLC/NLC collider, is composed of on the order of 100 cells. The cells are constructed as individual cups that are brazed together to form a structure. Fabrication error will result in slight cell-to-cell misalignments along the finished structure. In this report we derive an approximation to the transverse wakefield of a structure with cell-to-cell misalignments in terms of the eigenfunctions and eigenvalues of the erro...

  8. 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....... This can be used in complex treatment procedures such as gated intensity-modulated radiotherapy (IMRT)1, 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...

  9. SU-F-E-06: Dosimetric Characterization of Small Photons Beams of a Novel Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Almonte, A; Polanco, G; Sanchez, E [Instituto Oncologico Dr. Heriberto Pieter, Santo Domingo, Distrito Nacional (Dominican Republic)

    2016-06-15

    Purpose: The aim of the present contribution was to measure the main dosimetric quantities of small fields produced by UNIQUE and evaluate its matching with the corresponding dosimetric data of one 21EX conventional linear accelerator (Varian) in operation at the same center. The second step was to evaluate comparative performance of the EDGE diode detector and the PinPoint micro-ionization chamber for dosimetry of small fields. Methods: UNIQUE is configured with MLC (120 leaves with 0.5 cm leaf width) and a single low photon energy of 6 MV. Beam data were measured with scanning EDGE diode detector (volume of 0.019 mm{sup 3}), a PinPoint micro-ionization chamber (PTW) and for larger fields (≥ 4×4cm{sup 2}) a PTW Semi flex chamber (0.125 cm{sup 3}) was used. The scanning system used was the 3D cylindrical tank manufactured by Sun Nuclear, Inc. The measurement of PDD and profiles were done at 100 cm SSD and 1.5 depth; the relative output factors were measured at 10 cm depth. Results: PDD and the profile data showed less than 1% variation between the two linear accelerators for fields size between 2×2 cm{sup 2} and 5×5cm{sup 2}. Output factor differences was less than 1% for field sizes between 3×3 cm{sup 2} and 10×10 cm{sup 2} and less of 1.5 % for fields of 1.5×1.5 cm{sup 2} and 2×2 cm{sup 2} respectively. The dmax value of the EDGE diode detector, measured from the PDD, was 8.347 mm for 0.5×0,5cm{sup 2} for UNIQUE. The performance of EDGE diode detector was comparable for all measurements in small fields. Conclusion: UNIQUE linear accelerator show similar dosimetrics characteristics as conventional 21EX Varian linear accelerator for small, medium and large field sizes.EDGE detector show good performance by measuring dosimetrics quantities in small fields typically used in IMRT and radiosurgery treatments.

  10. Particle-in-Cell Code BEAMPATH for Beam Dynamics Simulations in Linear Accelerators and Beamlines

    Energy Technology Data Exchange (ETDEWEB)

    Batygin, Y.

    2004-10-28

    A code library BEAMPATH for 2 - dimensional and 3 - dimensional space charge dominated beam dynamics study in linear particle accelerators and beam transport lines is developed. The program is used for particle-in-cell simulation of axial-symmetric, quadrupole-symmetric and z-uniform beams in a channel containing RF gaps, radio-frequency quadrupoles, multipole lenses, solenoids and bending magnets. The programming method includes hierarchical program design using program-independent modules and a flexible combination of modules to provide the most effective version of the structure for every specific case of simulation. Numerical techniques as well as the results of beam dynamics studies are presented.

  11. Cumulative Beam Breakup in Linear Accelerators with Arbitrary Beam Current Profile

    Energy Technology Data Exchange (ETDEWEB)

    Jean Delayen

    2003-06-01

    An analytical formalism for the solution of cumulative beam breakup in linear accelerators with arbitrary time dependence of beam current is presented, and a closed-form expression for the time and position dependence of the transverse displacement is obtained. It is applied to the behavior of single bunches and to the steady state and transient behavior of dc beams and beams composed of point-like and finite length bunches. This formalism is also applied to the problem of cumulative beam breakup in the presence of random displacement of cavities and focusing elements, and a general solution is presented.

  12. Proposal of the Next Incarnation of Accelerator Test Facility at KEK for the International Linear Collider

    Energy Technology Data Exchange (ETDEWEB)

    Araki, S.; Hayano, H.; Higashi, Y.; Honda, Y.; Kanazawa, K.; Kubo, K.; Kume, T.; Kuriki, M.; Kuroda, S.; Masuzawa, M.; Naito, T.; Okugi, T.; Sugahara, R.; Takahashi, T.; Tauchi, T.; Terunuma, N.; Toge, N.; Urakawa, J.; Vogel, V.; Yamaoka, H.; Yokoya, K.; /KEK, Tsukuba /Beijing, Inst. High Energy Phys. /Novosibirsk, IYF /Daresbury /CERN /Hiroshima

    2005-05-27

    To reach design luminosity, the International Linear Collider (ILC) must be able to create and reliably maintain nanometer size beams. The ATF damping ring is the unique facility where ILC emittances are possible. In this paper we present and evaluate the proposal to create a final focus facility at the ATF which, using compact final focus optics and an ILC-like bunch train, would be capable of achieving 37 nm beam size. Such a facility would enable the development of beam diagnostics and tuning methods, as well as the training of young accelerator physicists.

  13. Overview of ten-year operation of the superconducting linear accelerator at the Spallation Neutron Source

    Science.gov (United States)

    Kim, S.-H.; Afanador, R.; Barnhart, D. L.; Crofford, M.; Degraff, B. D.; Doleans, M.; Galambos, J.; Gold, S. W.; Howell, M. P.; Mammosser, J.; McMahan, C. J.; Neustadt, T. S.; Peters, C.; Saunders, J. W.; Strong, W. H.; Vandygriff, D. J.; Vandygriff, D. M.

    2017-04-01

    The Spallation Neutron Source (SNS) has acquired extensive operational experience of a pulsed proton superconducting linear accelerator (SCL) as a user facility. Numerous lessons have been learned in its first 10 years operation to achieve a stable and reliable operation of the SCL. In this paper, an overview of the SNS SCL design, qualification of superconducting radio frequency (SRF) cavities and ancillary subsystems, an overview of the SNS cryogenic system, the SCL operation including SCL output energy history and downtime statistics, performance stability of the SRF cavities, efforts for SRF cavity performance recovery and improvement at the SNS, and maintenance activities for cryomodules are introduced.

  14. Contemporary methods of radiosurgery treatment with the Novalis linear accelerator system.

    Science.gov (United States)

    Chen, Joseph C T; Rahimian, Javad; Girvigian, Michael R; Miller, Michael J

    2007-01-01

    Radiosurgery has emerged as an indispensable component of the multidisciplinary approach to neoplastic, functional, and vascular diseases of the central nervous system. In recent years, a number of newly developed integrated systems have been introduced for radiosurgery and fractionated stereotactic radiotherapy treatments. These modern systems extend the flexibility of radiosurgical treatment in allowing the use of frameless image-guided radiation delivery as well as high-precision fractionated treatments. The Novalis linear accelerator system demonstrates adequate precision and reliability for cranial and extracranial radiosurgery, including functional treatments utilizing either frame-based or frameless image-guided methods.

  15. 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......-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...

  16. How to use composite indicator and linear programming model for determine sustainable tourism.

    Science.gov (United States)

    Ziaabadi, Maryam; Malakootian, Mohammad; Zare Mehrjerdi, Mohammad Reza; Jalaee, Seied Abdolmajid; Mehrabi Boshrabadi, Hosein

    2017-01-01

    The tourism industry which is one of the most dynamic economic activities in today's world plays a significant role in the sustainable development. Therefore, in addition to paying attention to tourism, sustainable tourism must be taken into huge account; otherwise, the environment and its health will be damaged irreparably. To determine the level of sustainability in this study, indicators of sustainable tourism were first presented in three environmental health, economic and social aspects. Then, the levels of sustainable tourism and environmental sustainability were practically measured in different cities of Kerman Province using a composite indicator, a linear programming model, Delphi method and the questionnaire technique. Finally, the study cities (tourist attractions) were ranked. Result of this study showed that unfortunately the tourism opportunities were not used appropriately in these cities and tourist destinations, and that environmental aspect (health and environmental sustainability) had very bad situations compared to social and economic aspects. In other words, environmental health had the lowest levels of sustainability. The environment is a place for all human activities like tourism, social and economic issues; therefore, its stability and health is of great importance. Thus, it is necessary to pay more attention to sustainability of activities, management and environmental health in planning sustainable development in regional and national policy.

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

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Pareja, S. [Servicio de Radiofisica Hospitalaria, Hospital Regional Universitario ' Carlos Haya' , Avda. Carlos Haya, s/n, E-29010 Malaga (Spain)], E-mail: garciapareja@gmail.com; Vilches, M. [Servicio de Fisica y Proteccion Radiologica, Hospital Regional Universitario ' Virgen de las Nieves' , Avda. de las Fuerzas Armadas, 2, E-18014 Granada (Spain); Lallena, A.M. [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, E-18071 Granada (Spain)

    2007-09-21

    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.

  18. Damped accelerator structures for future linear e/sup/plus minus// colliders

    Energy Technology Data Exchange (ETDEWEB)

    Deruyter, H.; Hoag, H.A.; Lisin, A.V.; Loew, G.A.; Palmer, R.B.; Paterson, J.M.; Rago, C.E.; Wang, J.W.

    1989-03-01

    This paper describes preliminary work on accelerator structures for future TeV linear colliders which use trains of e/sup +-/ bunches to reach the required luminosity. These bunch trains, if not perfectly aligned with respect to the accelerator axis, induce transverse wake field modes into the structure. Unless they are sufficiently damped, these modes cause cummulative beam deflections and emittance growth. The envisaged structures, originally proposed by R. B. Palmer, are disk-loaded waveguides in which the disks are slotted radially into quadrants. Wake field energy is coupled via the slots and double-ridged waveguides into a lossy region which is external to the accelerator structure. The requirement is that the Q of the HEM/sub 11/ mode be reduced to a value of less than 30. The work done so far includes MAFIA code computations and low power rf measurements to study the fields. A four-cavity 2..pi../3 mode standing-wave structure has been built to find whether the slots lower the electric breakdown thresholds below those reached with conventional disk-loaded structures. We set out to assess the microwave properties of the structure and the problems which might be encountered in fabricating it. 4 refs., 7 figs.

  19. Stereotactic irradiation using a linear accelerator for brain metastasis from renal cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Kawashima, Kazuyuki; Shirato, Hiroki; Miyasaka, Kazuo [Hokkaido Univ., Sapporo (Japan). School of Medicine; Takamura, Akira; Shinohara, Nobuo; Sawamura, Yutaka

    1997-07-01

    The role of stereotactic irradiation using a linear accelerator for brain metastasis from renal cell carcinoma was investigated. Fifteen brain metastases in 11 patients with a history of renal cell carcinoma were treated using convergent narrow x-ray beams from a linear accelerator and rigid fixation of the head with a stereotactic frame. Twelve metastatic tumors in 8 patients were irradiated with 25 Gy at the center in a single fraction, and single tumors in 3 patients received the following doses: 25 Gy in 5 fractions, 28 Gy in 3 fractions, or 35 Gy in 4 fractions. The actuarial local control rate at 12 months was 90.6%. Twelve (92%) of 13 lesions that produced neurologic symptoms before stereotactic irradiation showed an improvement of symptoms. No complication related to the irradiation was observed. The median survival time was 6 months. Stereotactic irradiation is more effective in achieving local control than is conventional radiotherapy, and achieves improvement in symptoms and survival rates similar to those of surgical resection of the brain metastasis from renal cell carcinoma. Urologists and oncologists should be aware of the usefulness of stereotactic radiation in the management of patients with renal cell carcinoma. (author)

  20. SU-E-T-124: Anthropomorphic Phantoms for Confirmation of Linear Accelerator Based Small Animal Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Perks, J; Benedict, S [UC Davis Cancer Center, Sacramento, CA (United States); Lucero, S [UC Davis, Davis, CA (United States)

    2015-06-15

    Purpose: To document the support of radiobiological small animal research by a modern radiation oncology facility. This study confirms that a standard, human use linear accelerator can cover the range of experiments called for by researchers performing animal irradiation. A number of representative, anthropomorphic murine phantoms were made. The phantoms confirmed the small field photon and electron beams dosimetry validated the use of the linear accelerator for rodents. Methods: Laser scanning a model, CAD design and 3D printing produced the phantoms. The phantoms were weighed and CT scanned to judge their compatibility to real animals. Phantoms were produced to specifically mimic lung, gut, brain, and othotopic lesion irradiations. Each phantom was irradiated with the same protocol as prescribed to the live animals. Delivered dose was measured with small field ion chambers, MOS/FETs or TLDs. Results: The density of the phantom material compared to density range across the real mice showed that the printed material would yield sufficiently accurate measurements when irradiated. The whole body, lung and gut irradiations were measured within 2% of prescribed doses with A1SL ion chamber. MOSFET measurements of electron irradiations for the orthotopic lesions allowed refinement of the measured small field output factor to better than 2% and validated the immunology experiment of irradiating one lesion and sparing another. Conclusion: Linacs are still useful tools in small animal bio-radiation research. This work demonstrated a strong role for the clinical accelerator in small animal research, facilitating standard whole body dosing as well as conformal treatments down to 1cm field. The accuracy of measured dose, was always within 5%. The electron irradiations of the phantom brain and flank tumors needed adjustment; the anthropomorphic phantoms allowed refinement of the initial output factor measurements for these fields which were made in a large block of solid water.

  1. SU-F-T-668: Irradiating Mouse Brain with a Clinical Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Torres, C [N Rancilio Purdue University, West Lafayette, IN (United States)

    2016-06-15

    Purpose: To design and construct a “mouse jig” device that would allow for irradiation of the mouse brain with a clinical Varian 6 MeV Linear Accelerator. This device must serve as a head immobilizer, gaseous anesthesia delivery, and radiation bolus concurrently. Methods: The mouse jig was machined out of nylon given that it is inexpensive, easy to machine, and has similar electron density to water. A cylindrical opening with diameter of 16 mm and 40 mm depth was drilled into a nylon block sized 56×56×50 mm (width, length, depth). Additional slots were included in the block for ear bars and a tooth bar to serve as a three-point immobilization device as well as for anesthesia delivery and scavenging. For ease of access when loading the mouse into the holder, there is a removable piece at the top of the block that is 15 mm in depth. This serves a dual purpose, as with the proper extra shielding, the mouse jig could be used with lower linear energy transfer photons with this piece removed. A baseplate was then constructed with five square slots where the mouse jig can securely be inserted plus additional slots that would allow the baseplate to be mounted on a standard lock bar in the treatment couch. This maximizes the reproducibility of placement between imaging and treatment and between treatment sessions. Results: CT imaging and radiation treatment planning was performed that showed acceptable coverage and uniformity of radiation dose in the mouse brain while sparing the throat and eyes. Conclusion: We have designed and manufactured a device that fulfills our criteria allowing us to selectively irradiate the mouse brain with a clinical linear accelerator. This setup will be used for generating mouse models of radiation-induced brain injury.

  2. 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)

  3. 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

  4. Accelerating the transition towards sustainability dynamics into supply chain relationship management and governance structures

    DEFF Research Database (Denmark)

    Govindan, Kannan; Seuring, Stefan; Zhu, Qinghua

    2016-01-01

    Stakeholders and competitive priorities drive profit and non-profit organizations towards the implementation of sustainability-related measures, in their internal operations, and in their supply chains planning. It is believed by some that investments in sustainability may help them to attain more...... successful futures by maintaining a healthy balance among economic, environmental, and social resources/dimensions. Consequently, some organizations have begun to integrate these dimensions in recent years. Researchers and practitioners are also working to accelerate the transition for more equitable...

  5. 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

  6. Quantitative Assessment of MeV Electron Acceleration in Non-Linear Interactions with VLF Chorus

    Science.gov (United States)

    Foster, J. C.; Erickson, P. J.; Omura, Y.; Baker, D. N.

    2016-12-01

    For occurrences of apparent rapid acceleration of radiation belt electrons to MeV energies at L 4, we examine the energy gained by seed electrons in non-linear (NL) interactions with VLF chorus rising tones. For the 17-18 March 2013 storm, observations of outer zone radiation belt electron populations were made with the magEIS and REPT instruments on Van Allen Probes A & B. These reveal that MeV electron fluxes at L=4.2 increased 10-fold in 30 min at the times of 30 - 100 keV electron injections during "substorm" dipolarizations. Simultaneous enhancements of VLF chorus were observed with the EMFISIS wave instruments. Three-axis burst mode observations of wave electric and magnetic fields have been used to investigate electron interactions with individual chorus rising tones on a sub millisecond time scale. Wave amplitudes at 2500 Hz were 1 nT (|B|) and 30 mV/m (|E|). Frequency - time characteristics of the observed chorus elements closely match those predicted by NL electron-chorus interaction modeling [Omura et al., 2015, J. Geophys. Res. Space Phys., 120, doi:10.1002/2015JA021563]. For seed electrons with initial energies 50 keV to 8 MeV, subpacket wave analysis was used to quantify resonant electron energy gain both by relativistic turning acceleration and by ultrarelativistic acceleration through nonlinear trapping by the chorus waves. Electrons with 1-2 MeV initial energy can experience a 300 keV total energy gain in NL interactions with a single 200 msec rising tone. Maximum energy gain from interaction with a single 10 msec subpacket was 100 keV for a 2 MeV seed electron. Examining a number of chorus elements at different locations during the rapid local acceleration of the radiation belt during this event, we conclude that seed electrons (100s keV - 5 MeV) can be accelerated by 50 keV - 500 keV in resonant NL interactions with a single VLF rising tone on a time scale of 10-100 msec.

  7. A data acquisition work station for ORELA (Oak Ridge Electron Linear Accelerator)

    Energy Technology Data Exchange (ETDEWEB)

    Rooney, B.D.; Todd, J.H.; Spencer, R.R.; Weston, L.W.

    1990-09-01

    A new multiparameter data acquisition system has been developed and fabricated at the Oak Ridge Electron Linear Accelerator (ORELA) which utilizes an IBM PS/2 Model 80 personal computer and data handler with a 2048 word buffer. The acquisition system can simultaneously acquire data from one, two, or three digitizers, multiplex up to four detectors, read and control up to 16 scalers, and output 32 DC logic signals which can be used to control external instrumentation. Software has been developed for the OS/2 operating system, supporting multiparameter data storage for up to three million channels with the capability of collecting data in a background mode, to make the computer available for other tasks while collecting data. The system also supports multiparameter biasing and can collect, crunch, and store data at rates as high as 30,000 events per second.

  8. High energy X-ray photon counting imaging using linear accelerator and silicon strip detectors

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Y., E-mail: cycjty@sophie.q.t.u-tokyo.ac.jp [Department of Bioengineering, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Shimazoe, K.; Yan, X. [Department of Nuclear Engineering and Management, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Ueda, O.; Ishikura, T. [Fuji Electric Co., Ltd., Fuji, Hino, Tokyo 191-8502 (Japan); Fujiwara, T. [National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); Uesaka, M.; Ohno, M. [Nuclear Professional School, the University of Tokyo, 2-22 Shirakata-shirane, Tokai, Ibaraki 319-1188 (Japan); Tomita, H. [Department of Quantum Engineering, Nagoya University, Furo, Chikusa, Nagoya 464-8603 (Japan); Yoshihara, Y. [Department of Nuclear Engineering and Management, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Takahashi, H. [Department of Bioengineering, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Department of Nuclear Engineering and Management, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2016-09-11

    A photon counting imaging detector system for high energy X-rays is developed for on-site non-destructive testing of thick objects. One-dimensional silicon strip (1 mm pitch) detectors are stacked to form a two-dimensional edge-on module. Each detector is connected to a 48-channel application specific integrated circuit (ASIC). The threshold-triggered events are recorded by a field programmable gate array based counter in each channel. The detector prototype is tested using 950 kV linear accelerator X-rays. The fast CR shaper (300 ns pulse width) of the ASIC makes it possible to deal with the high instant count rate during the 2 μs beam pulse. The preliminary imaging results of several metal and concrete samples are demonstrated.

  9. COMP report: CPQR technical quality control guideline for medical linear accelerators and multileaf collimators.

    Science.gov (United States)

    Kirkby, Charles; Ghasroddashti, Esmaeel; Angers, Crystal Plume; Zeng, Grace; Barnett, Erin

    2017-12-04

    The Canadian Organization of Medical Physicists (COMP), in close partnership with the Canadian Partnership for Quality Radiotherapy (CPQR) has developed a series of Technical Quality Control (TQC) guidelines for radiation treatment equipment. These guidelines outline the performance objectives that equipment should meet in order to ensure an acceptable level of radiation treatment quality. The TQC guidelines have been rigorously reviewed and field tested in a variety of Canadian radiation treatment facilities. The development process enables rapid review and update to keep the guidelines current with changes in technology (the most updated version of this guideline can be found on the CPQR website). This particular TQC details recommended quality control testing for medical linear accelerators and multileaf collimators. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  10. 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.

  11. Terahertz radiation source using a high-power industrial electron linear accelerator

    Science.gov (United States)

    Kalkal, Yashvir; Kumar, Vinit

    2017-04-01

    High-power (˜ 100 kW) industrial electron linear accelerators (linacs) are used for irradiations, 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 first pass through an undulator to generate useful terahertz (THz) radiation, and the spent electron beam coming out of the undulator can still be used for the intended industrial applications. This will enhance the utilization 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 μW can be produced, which may be useful for many scientific applications such as multispectral imaging of biological samples, chemical samples etc.

  12. REVIEW: Back to the future: the history and development of the clinical linear accelerator

    Science.gov (United States)

    Thwaites, David I.; Tuohy, John B.

    2006-07-01

    The linear accelerator (linac) is the accepted workhorse in radiotherapy in 2006. The first medical linac treated its first patient, in London, in 1953, so the use of these machines in clinical practice has been almost co-existent with the lifetime of Physics in Medicine and Biology. This review is a personal selection of things the authors feel are interesting in the history, particularly the early history, and development of clinical linacs. A brief look into the future is also given. One significant theme throughout is the continuity of ideas, building on previous experience. We hope the review might re-connect younger radiotherapy physicists in particular with some of the history and emphasize the continual need, in any human activity, to remain aware of the past, in order to make best use of past experience when taking decisions in the present.

  13. Kilovision: thermal modeling of a kilovoltage x-ray source integrated into a medical linear accelerator.

    Science.gov (United States)

    Cho, Youngbin; Munro, P

    2002-09-01

    The thermal and thermo-mechanical (fatigue) properties of a stationary-anode kilovoltage x-ray source that can be integrated into the head of a medical linear accelerator have been modeled. A finite element program has been used to model two new target designs. The first design makes minor modifications to the existing target assembly of a Varian medical linear accelerator, while the second design adds an additional cooling tube, changes the target angle, and uses a tungsten-rhenium alloy rather than tungsten as the kilovoltage target material. The thermal calculations have been used to generate cyclic stress/strain values from which estimates of fatigue in the target designs have been made. Both kilovoltage and megavoltage operation have been studied. Analysis of the megavoltage operation shows that there are only small differences in the thermal and fatigue characteristics after the target assembly is modified to include a kilovoltage target. Thus, megavoltage operation should not be compromised. The first kilovoltage target design can handle a 900 W heat load (e.g., 120 kVp, 7.5 mA, 2 x 2 mm2 source size); the heat load being limited by the temperature at the surface of the cooling tubes and mechanical fatigue at the surface of the target. The second design can handle a 1250 W heat load (e.g., 120 kVp, approximately 10.4 mA, 2 x 2 mm2 source size). Our calculations show that installation of a kilovoltage x-ray target is practical from thermal and thermo-mechanical perspectives.

  14. 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

  15. TU-FG-201-04: Computer Vision in Autonomous Quality Assurance of Linear Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Yu, H; Jenkins, C; Yu, S; Yang, Y; Xing, L [Stanford University, Stanford, CA (United States)

    2016-06-15

    Purpose: Routine quality assurance (QA) of linear accelerators represents a critical and costly element of a radiation oncology center. Recently, a system was developed to autonomously perform routine quality assurance on linear accelerators. The purpose of this work is to extend this system and contribute computer vision techniques for obtaining quantitative measurements for a monthly multi-leaf collimator (MLC) QA test specified by TG-142, namely leaf position accuracy, and demonstrate extensibility for additional routines. Methods: Grayscale images of a picket fence delivery on a radioluminescent phosphor coated phantom are captured using a CMOS camera. Collected images are processed to correct for camera distortions, rotation and alignment, reduce noise, and enhance contrast. The location of each MLC leaf is determined through logistic fitting and a priori modeling based on knowledge of the delivered beams. Using the data collected and the criteria from TG-142, a decision is made on whether or not the leaf position accuracy of the MLC passes or fails. Results: The locations of all MLC leaf edges are found for three different picket fence images in a picket fence routine to 0.1mm/1pixel precision. The program to correct for image alignment and determination of leaf positions requires a runtime of 21– 25 seconds for a single picket, and 44 – 46 seconds for a group of three pickets on a standard workstation CPU, 2.2 GHz Intel Core i7. Conclusion: MLC leaf edges were successfully found using techniques in computer vision. With the addition of computer vision techniques to the previously described autonomous QA system, the system is able to quickly perform complete QA routines with minimal human contribution.

  16. 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.

  17. Direct measurement of the image displacement instability in a linear induction accelerator

    Science.gov (United States)

    Burris-Mog, T. J.; Ekdahl, C. A.; Moir, D. C.

    2017-06-01

    The image displacement instability (IDI) has been measured on the 20 MeV Axis I of the dual axis radiographic hydrodynamic test facility and compared to theory. A 0.23 kA electron beam was accelerated across 64 gaps in a low solenoid focusing field, and the position of the beam centroid was measured to 34.3 meters downstream from the cathode. One beam dynamics code was used to model the IDI from first principles, while another code characterized the effects of the resistive wall instability and the beam break-up (BBU) instability. Although the BBU instability was not found to influence the IDI, it appears that the IDI influences the BBU. Because the BBU theory does not fully account for the dependence on beam position for coupling to cavity transverse magnetic modes, the effect of the IDI is missing from the BBU theory. This becomes of particular concern to users of linear induction accelerators operating in or near low magnetic guide fields tunes.

  18. Temporal characterization of ultrashort linearly chirped electron bunches generated from a laser wakefield accelerator

    Directory of Open Access Journals (Sweden)

    C. J. Zhang

    2016-06-01

    Full Text Available 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.

  19. 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.

  20. Measurement of depth-dose of linear accelerator and simulation by use of Geant4 computer code

    OpenAIRE

    Sardari, D.; Maleki, R.; Samavat, H.; Esmaeeli, A.

    2010-01-01

    Radiation therapy is an established method of cancer treatment. New technologies in cancer radiotherapy need a more accurate computation of the dose delivered in the radiotherapy treatment plan. This study presents some results of a Geant4-based application for simulation of the absorbed dose distribution given by a medical linear accelerator (LINAC). The LINAC geometry is accurately described in the Monte Carlo code with use of the accelerator manufacturer's specifications. The capability of...

  1. Sustained Accelerated Idioventricular Rhythm in a Centrifuge-Simulated Suborbital Spaceflight.

    Science.gov (United States)

    Suresh, Rahul; Blue, Rebecca S; Mathers, Charles; Castleberry, Tarah L; Vanderploeg, James M

    2017-08-01

    Hypergravitational exposures during human centrifugation are known to provoke dysrhythmias, including sinus dysrhythmias/tachycardias, premature atrial/ventricular contractions, and even atrial fibrillations or flutter patterns. However, events are generally short-lived and resolve rapidly after cessation of acceleration. This case report describes a prolonged ectopic ventricular rhythm in response to high G exposure. A previously healthy 30-yr-old man voluntarily participated in centrifuge trials as a part of a larger study, experiencing a total of 7 centrifuge runs over 48 h. Day 1 consisted of two +Gz runs (peak +3.5 Gz, run 2) and two +Gx runs (peak +6.0 Gx, run 4). Day 2 consisted of three runs approximating suborbital spaceflight profiles (combined +Gx and +Gz). Hemodynamic data collected included blood pressure, heart rate, and continuous three-lead electrocardiogram. Following the final acceleration exposure of the last Day 2 run (peak +4.5 Gx and +4.0 Gz combined, resultant +6.0 G), during a period of idle resting centrifuge activity (resultant vector +1.4 G), the subject demonstrated a marked change in his three-lead electrocardiogram from normal sinus rhythm to a wide-complex ectopic ventricular rhythm at a rate of 91-95 bpm, consistent with an accelerated idioventricular rhythm (AIVR). This rhythm was sustained for 2 m, 24 s before reversion to normal sinus. The subject reported no adverse symptoms during this time. While prolonged, the dysrhythmia was asymptomatic and self-limited. AIVR is likely a physiological response to acceleration and can be managed conservatively. Vigilance is needed to ensure that AIVR is correctly distinguished from other, malignant rhythms to avoid inappropriate treatment and negative operational impacts.Suresh R, Blue RS, Mathers C, Castleberry TL, Vanderploeg JM. Sustained accelerated idioventricular rhythm in a centrifuge-simulated suborbital spaceflight. Aerosp Med Hum Perform. 2017; 88(8):789-793.

  2. SLFP: a stochastic linear fractional programming approach for sustainable waste management.

    Science.gov (United States)

    Zhu, H; Huang, G H

    2011-12-01

    A stochastic linear fractional programming (SLFP) approach is developed for supporting sustainable municipal solid waste management under uncertainty. The SLFP method can solve ratio optimization problems associated with random information, where chance-constrained programming is integrated into a linear fractional programming framework. It has advantages in: (1) comparing objectives of two aspects, (2) reflecting system efficiency, (3) dealing with uncertainty expressed as probability distributions, and (4) providing optimal-ratio solutions under different system-reliability conditions. The method is applied to a case study of waste flow allocation within a municipal solid waste (MSW) management system. The obtained solutions are useful for identifying sustainable MSW management schemes with maximized system efficiency under various constraint-violation risks. The results indicate that SLFP can support in-depth analysis of the interrelationships among system efficiency, system cost and system-failure risk. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Influence of a transverse magnetic field on the dose deposited by a 6 MV linear accelerator

    Directory of Open Access Journals (Sweden)

    Richter Sebastian

    2017-09-01

    Full Text Available An integrated system of a linear accelerator and a magnetic resonance imaging (MRI device may provide real-time imaging during radiotherapy treatments. This work investigated changes affecting the dose deposition caused by a magnetic field (B-field transverse to the beam direction by means of Monte Carlo simulations. Two different phantoms were used: A water phantom (Ph1 and a water-air phantom (Ph2 with a 4-2-4 cm water-air-water cross section. Dose depositions were scored for B-field values of 0 T, 0.35 T, 0.5 T, 1.5 T, 3 T and 5 T. Beams were based on a precalculated photon spectrum taken from an earlier simulated Elekta 6 MV FFF accelerator. All lateral profiles in Ph1 showed a Lorentz force driven shift w.r.t. the B-field strength, presenting a steeper penumbra in the shift's direction. Depositions were shifted up to 0.3 cm for 5 T, showing a constant central axis plateau-dose or an increase by 2.3 % for small fields. Depth-dose curves in Ph1 showed a shift of the dose maximum towards the beam entrance direction for increasing B-field of up to 1.1 cm; the maximum dose was increased by 6.9 %. In Ph2, an asymmetric dose increase by up to 36.9 % was observed for 1.5 T at the water-air boundary, resulting from the electron return effect (ERE. In our scenario, B-field dependent dose shifts and local build-ups were observed, which consequently affect the resulting dose distribution and need to be considered in magnetic resonance guided radiotherapy treatment planning.

  4. Measurement of changes in linear accelerator photon energy through flatness variation using an ion chamber array.

    Science.gov (United States)

    Gao, Song; Balter, Peter A; Rose, Mark; Simon, William E

    2013-04-01

    To compare the use of flatness versus percent depth dose (PDD) for determining changes in photon beam energy for a megavoltage linear accelerator. Energy changes were accomplished by adjusting the bending magnet current by up to ± 15% in 5% increments away from the value used clinically. Two metrics for flatness, relative flatness in the central 80% of the field (Flat) and average maximum dose along the diagonals normalized by central axis dose (FDN), were measured using a commercially available planner ionization chamber array. PDD was measured in water at depths of 5 and 10 cm in 3 × 3 cm(2) and 10 × 10 cm(2) fields using a cylindrical chamber. PDD was more sensitive to changes in energy when the beam energy was increased than when it was decreased. For the 18-MV beam in particular, PDD was not sensitive to energy reductions below the nominal energy. The value of Flat was found to be more sensitive to decreases in energy than to increases, with little sensitivity to energy increases above the nominal energy for 18-MV beams. FDN was the only metric that was found to be sensitive to both increases and reductions of energy for both the 6- and 18-MV beams. Flatness based metrics were found to be more sensitive to energy changes than PDD, In particular, FDN was found to be the most sensitive metric to energy changes for photon beams of 6 and 18 MV. The ionization chamber array allows this metric to be conveniently measured as part of routine accelerator quality assurance.

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

    Science.gov (United States)

    St Aubin, Joel; Steciw, Stephen; Fallone, B G

    2010-02-01

    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 40 x 40 cm2 field dose profile. 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.

  6. 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

  7. Optimal technique of linear accelerator-based stereotactic radiosurgery for tumors adjacent to brainstem.

    Science.gov (United States)

    Chang, Chiou-Shiung; Hwang, Jing-Min; Tai, Po-An; Chang, You-Kang; Wang, Yu-Nong; Shih, Rompin; Chuang, Keh-Shih

    2016-01-01

    Stereotactic radiosurgery (SRS) is a well-established technique that is replacing whole-brain irradiation in the treatment of intracranial lesions, which leads to better preservation of brain functions, and therefore a better quality of life for the patient. There are several available forms of linear accelerator (LINAC)-based SRS, and the goal of the present study is to identify which of these techniques is best (as evaluated by dosimetric outcomes statistically) when the target is located adjacent to brainstem. We collected the records of 17 patients with lesions close to the brainstem who had previously been treated with single-fraction radiosurgery. In all, 5 different lesion catalogs were collected, and the patients were divided into 2 distance groups-1 consisting of 7 patients with a target-to-brainstem distance of less than 0.5cm, and the other of 10 patients with a target-to-brainstem distance of ≥ 0.5 and radiosurgery: dynamic conformal arcs (DCA), intensity-modulated radiosurgery (IMRS), and volumetric modulated arc radiotherapy (VMAT). All techniques included multiple noncoplanar beams or arcs with or without intensity-modulated delivery. The volume of gross tumor volume (GTV) ranged from 0.2cm(3) to 21.9cm(3). Regarding the dose homogeneity index (HIICRU) and conformity index (CIICRU) were without significant difference between techniques statistically. However, the average CIICRU = 1.09 ± 0.56 achieved by VMAT was the best of the 3 techniques. Moreover, notable improvement in gradient index (GI) was observed when VMAT was used (0.74 ± 0.13), and this result was significantly better than those achieved by the 2 other techniques (p < 0.05). For V4Gy of brainstem, both VMAT (2.5%) and IMRS (2.7%) were significantly lower than DCA (4.9%), both at the p < 0.05 level. Regarding V2Gy of normal brain, VMAT plans had attained 6.4 ± 5%; this was significantly better (p < 0.05) than either DCA or IMRS plans, at 9.2 ± 7% and 8.2 ± 6%, respectively. Owing to

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

    Directory of Open Access Journals (Sweden)

    Avkshtol V

    2016-08-01

    Full Text Available Vladimir Avkshtol, Yanqun Dong, Shelly B Hayes, Mark A Hallman, Robert A Price, Mark L Sobczak, Eric M Horwitz,* Nicholas G Zaorsky* Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA, USA *These authors contributed equally to this work Abstract: 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 (<6% grade 3–4 late toxicities. Other outcomes (eg, overall and 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

  9. 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

  10. Photoneutron intensity variation with field size around radiotherapy linear accelerator 18-MeV X-ray beam

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ghamdi, H.; Fazal-ur-Rehman [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Jarallah, M.I. [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)], E-mail: mibrahim@kfupm.edu.sa; Maalej, N. [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2008-08-15

    In X-ray radiotherapy accelerators, neutrons are produced mainly by ({gamma},n) reaction when high energy X-rays interact with high Z materials of the linear accelerator head. These materials include the lead (Pb) used as shielding in the collimator, tungsten (W) target used for the production of X-rays and iron (Fe) in the accelerator head. These unwanted neutrons contaminate the therapeutic beam and contribute to the patient dose during the treatment of a cancer patient. Knowing the neutron distribution around the radiotherapy accelerator is therefore desired. CR-39 nuclear track detectors (NTDs) were used to study the variation of fast and thermal neutron relative intensities around an 18 MeV linear accelerator X-ray beam with the field sizes of 0, 10x10, 20x20, 30x30 and 40x40cm{sup 2}. For fast neutron detection, bare NTDs were used. For thermal neutron detection, NTDs were covered with lithium tetra borate (Li{sub 2}B{sub 4}O{sub 7}) converters. The NTDs were placed at different locations in the direction perpendicular to the treatment couch (transversal) and in the direction parallel to the treatment couch (longitudinal) with respect to the isocenter of the accelerator. The fast neutron relative intensity is symmetrical about the beam axis and exhibits an exponential-like drop with distance from the isocenter of the accelerator for all the field sizes. At the primary beam (isocenter), the relative fast neutron intensity is highest for 40x40cm{sup 2} field size and decreases linearly with the decrease in the field size. However, fast neutron intensities do not change significantly with beam size for the measurements outside the primary beam. The fast neutron intensity in the longitudinal direction outside the primary beam decreases linearly with the field size. The thermal neutron intensity, at any location, was found to be almost independent of the field size.

  11. Accuracy evaluation of the optical surface monitoring system on EDGE linear accelerator in a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Mancosu, Pietro; Fogliata, Antonella, E-mail: Antonella.Fogliata@humanitas.it; Stravato, Antonella; Tomatis, Stefano; Cozzi, Luca; Scorsetti, Marta

    2016-07-01

    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 3 cm, (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 ± 0.3 mm for linear vector displacement, with a maximum rotational inaccuracy of 0.3°. OSMS presented an accuracy of 0.3 mm for displacement up to 1 cm and 1°, and 0.5 mm for larger displacements. Different couch angles (45° and 90°) induced a mean vector uncertainty < 0.4 mm. Coverage of 1 camera produced an uncertainty < 0.5 mm. Translations and rotations of a phantom can be accurately detect with the optical surface detector system.

  12. Linear and second order optics corrections for the KEK Accelerator Test Facility final focus beam line

    Directory of Open Access Journals (Sweden)

    T. Okugi

    2014-02-01

    Full Text Available In this paper, the linear and second order optics corrections for the KEK Accelerator Test Facility (ATF2 final focus beam line are described. The beam optics of the ATF2 beam line is designed based on a local chromaticity correction scheme similar to the ILC final focus system. Beam measurements in 2012 revealed skew sextupole field errors that were much larger than expected from magnetic field measurements. The skew sextupole field error was a critical limitation of the beam size at the ATF2 virtual interaction point (IP. Therefore, four skew sextupole magnets were installed to correct the field error in August 2012. By using the four skew sextupole magnets, the predicted tolerances of the skew sextupole field errors of the ATF2 magnets were increased. Furthermore, analyzing field maps of the sextupole magnets identified the source of the skew sextupole field error. After the field error source was removed, the IP vertical beam size could more easily be focused to less than 65 nm.

  13. 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...

  14. Accelerated Cyclic Reduction: A Distributed-Memory Fast Solver for Structured Linear Systems

    KAUST Repository

    Chávez, Gustavo

    2017-12-15

    We present Accelerated Cyclic Reduction (ACR), a distributed-memory fast solver for rank-compressible block tridiagonal linear systems arising from the discretization of elliptic operators, developed here for three dimensions. Algorithmic synergies between Cyclic Reduction and hierarchical matrix arithmetic operations result in a solver that has O(kNlogN(logN+k2)) arithmetic complexity and O(k Nlog N) memory footprint, where N is the number of degrees of freedom and k is the rank of a block in the hierarchical approximation, and which exhibits substantial concurrency. We provide a baseline for performance and applicability by comparing with the multifrontal method with and without hierarchical semi-separable matrices, with algebraic multigrid and with the classic cyclic reduction method. Over a set of large-scale elliptic systems with features of nonsymmetry and indefiniteness, the robustness of the direct solvers extends beyond that of the multigrid solver, and relative to the multifrontal approach ACR has lower or comparable execution time and size of the factors, with substantially lower numerical ranks. ACR exhibits good strong and weak scaling in a distributed context and, as with any direct solver, is advantageous for problems that require the solution of multiple right-hand sides. Numerical experiments show that the rank k patterns are of O(1) for the Poisson equation and of O(n) for the indefinite Helmholtz equation. The solver is ideal in situations where low-accuracy solutions are sufficient, or otherwise as a preconditioner within an iterative method.

  15. Absolute energy calibration of the Telescope Array fluorescence detector with an electron linear accelerator

    Directory of Open Access Journals (Sweden)

    Shin B.K.

    2013-06-01

    Full Text Available The Electron Light Source(ELS is a new light source for the absolute energy calibration of cosmic ray Fluorescence Detector(FD telescopes. The ELS is a compact electron linear accelerator with a typical output of 109 electrons per pulse at 40 MeV. We fire the electron beam vertically into the air 100 m in front of the telescope. The electron beam excites the gases of the atmosphere in the same way as the charged particles of the cosmic ray induced extensive air shower. The gases give off the same light with the same wavelength dependence. The light passes through a small amount of atmosphere and is collected by the same mirror and camera with their wavelength dependence. In this way we can use the electron beam from ELS to make an end-to-end calibration of the telescope. In September 2010, we began operation of the ELS and the FD telescopes observed the fluorescence photons from the air shower which was generated by the electron beam. In this article, we will reort the status of analysis of the absolute energy calibration with data which was taken in September 2010, and beam monitor study in November 2011.

  16. Standard Test Method for Measuring Dose for Use in Linear Accelerator Pulsed Radiation Effects Tests

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This test method covers a calorimetric measurement of the total dose delivered in a single pulse of electrons from an electron linear accelerator or a flash X-ray machine (FXR, e-beam mode) used as an ionizing source in radiation-effects testing. The test method is designed for use with pulses of electrons in the energy range from 10 to 50 MeV and is only valid for cases in which both the calorimeter and the test specimen to be irradiated are“thin” compared to the range of these electrons in the materials of which they are constructed. 1.2 The procedure described can be used in those cases in which (1) the dose delivered in a single pulse is 5 Gy (matl) (500 rd (matl)) or greater, or (2) multiple pulses of a lower dose can be delivered in a short time compared to the thermal time constant of the calorimeter. Matl refers to the material of the calorimeter. The minimum dose per pulse that can be acceptably monitored depends on the variables of the particular test, including pulse rate, pulse uniformity...

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

    Energy Technology Data Exchange (ETDEWEB)

    Janssen, Rogier W J; Dries, Wim J F [Catharina-Hospital Eindhoven, PO Box 1350, 5602 ZA, Eindhoven (Netherlands); Faddegon, Bruce A [University of California San Francisco Comprehensive Cancer Center, 1600 Divisadero Street, San Francisco, CA 94115-1708 (United States)], E-mail: rogier.janssen@mac.com

    2008-04-21

    The treatment of large tumors such as sarcomas with intra-operative radiotherapy using a Mobetron (registered) is often complicated because of the limited field size of the primary collimator and the available applicators (max Oe100 mm). To circumvent this limitation a prototype rectangular applicator of 80 x 150 mm{sup 2} 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 (registered) 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 x 150 mm{sup 2} 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.

  18. Beam characterization of 10-MV photon beam from medical linear accelerator without flattening filter

    Directory of Open Access Journals (Sweden)

    Tomohiro Shimozato

    2017-01-01

    Full Text Available Aim: This work investigated the dosimetric properties of a 10-MV photon beam emitted from a medical linear accelerator (linac with no flattening filter (FF. The aim of this study is to analyze the radiation fluence and energy emitted from the flattening filter free (FFF linac using Monte Carlo (MC simulations. Materials and Methods: The FFF linac was created by removing the FF from a linac in clinical use. Measurements of the depth dose (DD and the off-axis profile were performed using a three-dimensional water phantom with an ionization chamber. A MC simulation for a 10-MV photon beam from this FFF linac was performed using the BEAMnrc code. Results: The off-axis profiles for the FFF linac exhibited a chevron-like distribution, and the dose outside the irradiation field was found to be lower for the FFF linac than for a linac with an FF (FF linac. The DD curves for the FFF linac included many contaminant electrons in the build-up region. Conclusion: Therefore, for clinical use, a metal filter is additionally required to reduce the effects of the electron contamination. The mean energy of the FFF linac was found to be lower than that of the FF linac owing to the absence of beam hardening caused by the FF.

  19. Design of 6 Mev linear accelerator based pulsed thermal neutron source: FLUKA simulation and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Patil, B.J., E-mail: bjp@physics.unipune.ac.in [Department of Physics, University of Pune, Pune 411 007 (India); Chavan, S.T.; Pethe, S.N.; Krishnan, R. [SAMEER, IIT Powai Campus, Mumbai 400 076 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune 411 007 (India); Dhole, S.D., E-mail: sanjay@physics.unipune.ac.in [Department of Physics, University of Pune, Pune 411 007 (India)

    2012-01-15

    The 6 MeV LINAC based pulsed thermal neutron source has been designed for bulk materials analysis. The design was optimized by varying different parameters of the target and materials for each region using FLUKA code. The optimized design of thermal neutron source gives flux of 3 Multiplication-Sign 10{sup 6}ncm{sup -2}s{sup -1} with more than 80% of thermal neutrons and neutron to gamma ratio was 1 Multiplication-Sign 10{sup 4}ncm{sup -2}mR{sup -1}. The results of prototype experiment and simulation are found to be in good agreement with each other. - Highlights: Black-Right-Pointing-Pointer The optimized 6 eV linear accelerator based thermal neutron source using FLUKA simulation. Black-Right-Pointing-Pointer Beryllium as a photonuclear target and reflector, polyethylene as a filter and shield, graphite as a moderator. Black-Right-Pointing-Pointer Optimized pulsed thermal neutron source gives neutron flux of 3 Multiplication-Sign 10{sup 6} n cm{sup -2} s{sup -1}. Black-Right-Pointing-Pointer Results of the prototype experiment were compared with simulations and are found to be in good agreement. Black-Right-Pointing-Pointer This source can effectively be used for the study of bulk material analysis and activation products.

  20. 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)

  1. Accelerating Sustainability by Hydropower Development in China: The Story of HydroLancang

    Directory of Open Access Journals (Sweden)

    Yan Zhang

    2017-07-01

    Full Text Available Sustainable development is a shared responsibility. Accelerating sustainability of water–energy–people nexus and building a common awareness of issues pertaining to sustainable development are essential for any sort of success in this direction. Hydropower has been a useful sustainable energy for development, yet highly controversial. This paper reviews the overall situation of hydropower development and China’s energy reforms and policies, accompanied with a case study of hydropower development the Lancang River by the HydroLancang, aiming to illustrate the two opposite sides of hydropower development—economy and environment. The paper concludes with a neutral view of hydropower as the necessary facilitator for development. Water is a shared responsibility. Hydropower might not be the optimum solution to eliminate the tension between human demand of energy and finite natural resource and the rising pressure of climate change worldwide, but it serves well as an “Electricity Bridge” before better alternatives become available. This is a more balanced view of hydropower rather than two extreme viewpoints that present themselves: on the one hand, exaggerated claims of the human power to tame the wild river, and, on the other hand, the idealistic fantasy of preserving nature by abandoning all human activity.

  2. 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)

  3. Evaluation of the repeatability of dosimetric parameters of a linear accelerator beam; Avaliacao da repetibilidade de parametros dosimetricos do feixe de um acelerador linear

    Energy Technology Data Exchange (ETDEWEB)

    Morelli, Humberto A.S.; Oliveira, Harley F. de; Silva, Maelson do N.; Pavoni, Juliana F., E-mail: h.morelli@hotmail.com [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Servico de Radioterapia

    2016-07-01

    This study aims to evaluate the repeatability of symmetry and flatness of the photon beam of 6 MV linear accelerator Oncor Impression, Siemens, from the Radiotherapy Department of the Hospital das Clinicas da Faculdade de Medicina de Ribeirao Preto - USP. In total they were collected 102 measures, weekly, through two-dimensional detector of ionization chambers, Matrixx Evolution, IBA Dosimetry, connected to a computer with software OmniProI'mrt. The isocenter of the linear accelerator was placed in the center of the sensitive volume of the detector with solid water plates above and below these. Data were collected with 100 UM, with field size 10 x 10 cm². The flatness and symmetry values were calculated by the software used. The first measurement of this work was used as reference, the others were compared with it, taking into account the values of permissible variation for these parameters. The minimum, maximum and average value were analyzed. The literature indicates that the flatness and symmetry values should not vary by more than 2 and 3%, respectively. The results of this work show that the values of these parameters for the linear accelerator study are within the permissible variations in protocols and are therefore able to appropriate clinical use. (author)

  4. Application of gas-cooled Accelerator Driven System (ADS) transmutation devices to sustainable nuclear energy development

    Energy Technology Data Exchange (ETDEWEB)

    Abanades, A., E-mail: abanades@etsii.upm.es [ETSII/Universidad Politecnica de Madrid, J.Gutierrez Abascal, 2-28006 Madrid (Spain); Garcia, C.; Garcia, L. [Instituto Superior de Tecnologia y Ciencias Aplicadas. Quinta de los, Molinos, Ave. Salvador Allende y Luaces, Ciudad de la Habana, CP 10400, Apartado Postal 6163 (Cuba); Escriva, A.; Perez-Navarro, A. [Instituto de Ingenieria Energetica, Universidad Politecnica de Valencia, C.P. 46022 Valencia (Spain); Rosales, J. [Instituto Superior de Tecnologia y Ciencias Aplicadas. Quinta de los, Molinos, Ave. Salvador Allende y Luaces, Ciudad de la Habana, CP 10400, Apartado Postal 6163 (Cuba)

    2011-06-15

    Highlights: > Utilization of Accelerator Driven System (ADS) for Hydrogen production. > Evaluation of the potential use of gas-cooled ADS for a sustainable use of Uranium resources by transmutation of nuclear wastes, electricity and Hydrogen production. > Application of the Sulfur-Iodine thermochemical process to subcritical systems. > Application of CINDER90 to calculate burn-up in subcritical systems. - Abstract: The conceptual design of a pebble bed gas-cooled transmutation device is shown with the aim to evaluate its potential for its deployment in the context of the sustainable nuclear energy development, which considers high temperature reactors for their operation in cogeneration mode, producing electricity, heat and Hydrogen. As differential characteristics our device operates in subcritical mode, driven by a neutron source activated by an accelerator that adds clear safety advantages and fuel flexibility opening the possibility to reduce the nuclear stockpile producing energy from actual LWR irradiated fuel with an efficiency of 45-46%, either in the form of Hydrogen, electricity, or both.

  5. 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

  6. Clinical commissioning and use of the Novalis Tx linear accelerator for SRS and SBRT.

    Science.gov (United States)

    Kim, Jinkoo; Wen, Ning; Jin, Jian-Yue; Walls, Nicole; Kim, Sangroh; Li, Haisen; Ren, Lei; Huang, Yimei; Doemer, Anthony; Faber, Kathleen; Kunkel, Tina; Balawi, Ahssan; Garbarino, Kimberly; Levin, Kenneth; Patel, Samir; Ajlouni, Munther; Miller, Brett; Nurushev, Teamor; Huntzinger, Calvin; Schulz, Raymond; Chetty, Indrin J; Movsas, Benjamin; Ryu, Samuel

    2012-05-10

    The purpose of this study was to perform comprehensive measurements and testing of a Novalis Tx linear accelerator, and to develop technical guidelines for com-missioning from the time of acceptance testing to the first clinical treatment. The Novalis Tx (NTX) linear accelerator is equipped with, among other features, a high-definition MLC (HD120 MLC) with 2.5 mm central leaves, a 6D robotic couch, an optical guidance positioning system, as well as X-ray-based image guidance tools to provide high accuracy radiation delivery for stereotactic radiosurgery and stereotactic body radiation therapy procedures. We have performed extensive tests for each of the components, and analyzed the clinical data collected in our clinic. We present technical guidelines in this report focusing on methods for: (1) efficient and accurate beam data collection for commissioning treatment planning systems, including small field output measurements conducted using a wide range of detectors; (2) commissioning tests for the HD120 MLC; (3) data collection for the baseline characteristics of the on-board imager (OBI) and ExacTrac X-ray (ETX) image guidance systems in conjunction with the 6D robotic couch; and (4) end-to-end testing of the entire clinical process. Established from our clinical experience thus far, recommendations are provided for accurate and efficient use of the OBI and ETX localization systems for intra- and extracranial treatment sites. Four results are presented. (1) Basic beam data measurements: Our measurements confirmed the necessity of using small detectors for small fields. Total scatter factors varied significantly (30% to approximately 62%) for small field measurements among detectors. Unshielded stereotactic field diode (SFD) overestimated dose by ~ 2% for large field sizes. Ion chambers with active diameters of 6 mm suffered from significant volume averaging. The sharpest profile penumbra was observed for the SFD because of its small active diameter (0.6 mm). (2

  7. 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.

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

    Science.gov (United States)

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

    2015-07-23

    To retrospectively access outcome and prognostic parameters of linear accelerator-based stereotactic radiosurgery in brain metastases from malignant melanoma. 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 diameter was 12 mm. The median dose applied was 20 Gy/80 % isodose enclosing. The median follow-up was 7 months and the median overall survival 9 months. The 6-, 12- and 24 month overall survival rates were 71 %, 39 % and 25 % respectively. Cerebral follow-up imaging showed complete remission in 20 brain metastases, partial remission in 39 brain metastases, stable disease in 54 brain metastases, progressive disease in 24 brain metastases and pseudo-progression in 3 brain metastases. Median intracerebral control was 5.3 months and the 6- and 12-month intracerebral progression-free survival rates 48 % and 38 %, respectively. Upon univariate analysis, extracerebral control (log-rank, p stereotactic radiosurgery (log-rank, p stereotactic radiosurgery high dose region. Stereotactic radiosurgery is a well-tolerated and effective treatment option for brain metastases in malignant melanoma and was able to achieve local remissions in several cases. Furthermore, especially patients with controlled extracerebral disease and a low count of brain metastases seem to benefit from this treatment modality. Prospective trials analysing the effects of combined stereotactic radiosurgery and new systemic agents are warranted.

  9. Evaluation of linear accelerator-based stereotactic radiosurgery in the management of glomus jugulare tumors.

    Science.gov (United States)

    Sager, Omer; Beyzadeoglu, Murat; Dincoglan, Ferrat; Gamsiz, Hakan; Demiral, Selcuk; Uysal, Bora; Oysul, Kaan; Dirican, Bahar; Sirin, Sait

    2014-01-01

    Although mostly benign and slow-growing, glomus jugulare tumors have a high propensity for local invasion of adjacent vascular structures, lower cranial nerves and the inner ear, which may result in substantial morbidity and even mortality. Treatment strategies for glomus jugulare tumors include surgery, preoperative embolization followed by surgical resection, conventionally fractionated external beam radiotherapy, radiosurgery in the form of stereotactic radiosurgery or fractionated stereotactic radiation therapy, and combinations of these modalities. In the present study, we evaluate the use of linear accelerator (LINAC)-based stereotactic radiosurgery in the management of glomus jugulare tumors and report our 15-year single center experience. Between May 1998 and May 2013, 21 patients (15 females, 6 males) with glomus jugulare tumors were treated using LINAC-based stereotactic radiosurgery at the Department of Radiation Oncology, Gulhane Military Medical Academy. The indication for stereotactic radiosurgery was the presence of residual or recurrent tumor after surgery for 5 patients, whereas 16 patients having growing tumors with symptoms received stereotactic radiosurgery as the primary treatment. Median follow-up was 49 months (range, 3-98). Median age was 55 years (range, 24-77). Of the 21 lesions treated, 13 (61.9%) were left-sided and 8 (38.1%) were right-sided. Median dose was 15 Gy (range, 10-20) prescribed to the 85%-100% isodose line encompassing the target volume. Local control defined as either tumor shrinkage or the absence of tumor growth on periodical follow-up neuroimaging was 100%. LINAC-based stereotactic radiosurgery offers a safe and efficacious management strategy for glomus jugulare tumors by providing excellent tumor growth control with few complications.

  10. MO-DE-BRA-02: SIMAC: A Simulation Tool for Teaching Linear Accelerator Physics

    Energy Technology Data Exchange (ETDEWEB)

    Carlone, M; Harnett, N [Princess Margaret Hospital, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Harris, W [Duke University Medical Physics Graduate Program, Durham NC (United States); Norrlinger, B [Princess Margaret Hospital, Toronto, ON (Canada); MacPherson, M [The Ottawa Hospital, Ottawa, Ontario (Canada); Lamey, M [Trillium Health Partners, Mississauga, Ontario (Canada); Oldham, M [Duke University Medical Medical Center, Durham NC (United States); Duke University Medical Physics Graduate Program, Durham NC (United States); Anderson, R

    2016-06-15

    Purpose: The first goal of this work is to develop software that can simulate the physics of linear accelerators (linac). The second goal is to show that this simulation tool is effective in teaching linac physics to medical physicists and linac service engineers. Methods: Linacs were modeled using analytical expressions that can correctly describe the physical response of a linac to parameter changes in real time. These expressions were programmed with a graphical user interface in order to produce an environment similar to that of linac service mode. The software, “SIMAC”, has been used as a learning aid in a professional development course 3 times (2014 – 2016) as well as in a physics graduate program. Exercises were developed to supplement the didactic components of the courses consisting of activites designed to reinforce the concepts of beam loading; the effect of steering coil currents on beam symmetry; and the relationship between beam energy and flatness. Results: SIMAC was used to teach 35 professionals (medical physicists; regulators; service engineers; 1 week course) as well as 20 graduate students (1 month project). In the student evaluations, 85% of the students rated the effectiveness of SIMAC as very good or outstanding, and 70% rated the software as the most effective part of the courses. Exercise results were collected showing that 100% of the students were able to use the software correctly. In exercises involving gross changes to linac operating points (i.e. energy changes) the majority of students were able to correctly perform these beam adjustments. Conclusion: Software simulation(SIMAC), can be used to effectively teach linac physics. In short courses, students were able to correctly make gross parameter adjustments that typically require much longer training times using conventional training methods.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ciocca, Mario, E-mail: mario.ciocca@cnao.it [Unit of Medical Physics, Centro Nazionale di Adroterapia Oncologica (CNAO) Foundation, via Campeggi, 27100 Pavia (Italy); Cantone, Marie-Claire; Veronese, Ivan [Department of Physics, Universita degli Studi di Milano, via Celoria 16, 20133 Milano (Italy); Istituto Nazionale di Fisica Nucleare, INFN Milano, via Celoria 16, 20133 Milano (Italy); Cattani, Federica; Pedroli, Guido [Unit of Medical Physics, European Institute of Oncology, via Ripamonti 435, 20141 Milano (Italy); Molinelli, Silvia [Unit of Medical Physics, Centro Nazionale di Adroterapia Oncologica (CNAO) Foundation, via Campeggi, 27100 Pavia (Italy); Vitolo, Viviana [Unit of Radiotherapy, Centro Nazionale di Adroterapia Oncologica (CNAO) Foundation, via Campeggi, 27100 Pavia (Italy); Orecchia, Roberto [Division of Radiation Oncology, European Institute of Oncology, via Ripamonti 435, 20141 Milano (Italy); Scientific Direction, Centro Nazionale di Adroterapia Oncologica (CNAO) Foundation, via Campeggi, 27100 Pavia (Italy); Faculty of Medicine, Universita degli Studi di Milano, via Ripamonti 435, 20141 Milano (Italy)

    2012-02-01

    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. The

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

    Science.gov (United States)

    Kry, Stephen F; Howell, Rebecca M; Polf, Jerimy; Mohan, Radhe; Vassiliev, Oleg N

    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(3) less concrete to shield the single-energy linac and 36 m(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.

  13. A Comparison Between GATE and MCNPX Monte Carlo Codes in Simulation of Medical Linear Accelerator

    Science.gov (United States)

    Sadoughi, Hamid-Reza; Nasseri, Shahrokh; Momennezhad, Mahdi; Sadeghi, Hamid-Reza; Bahreyni-Toosi, Mohammad-Hossein

    2014-01-01

    Radiotherapy dose calculations can be evaluated by Monte Carlo (MC) simulations with acceptable accuracy for dose prediction in complicated treatment plans. In this work, Standard, Livermore and Penelope electromagnetic (EM) physics packages of GEANT4 application for tomographic emission (GATE) 6.1 were compared versus Monte Carlo N-Particle eXtended (MCNPX) 2.6 in simulation of 6 MV photon Linac. To do this, similar geometry was used for the two codes. The reference values of percentage depth dose (PDD) and beam profiles were obtained using a 6 MV Elekta Compact linear accelerator, Scanditronix water phantom and diode detectors. No significant deviations were found in PDD, dose profile, energy spectrum, radial mean energy and photon radial distribution, which were calculated by Standard and Livermore EM models and MCNPX, respectively. Nevertheless, the Penelope model showed an extreme difference. Statistical uncertainty in all the simulations was Penelope models, respectively. Differences between spectra in various regions, in radial mean energy and in photon radial distribution were due to different cross section and stopping power data and not the same simulation of physics processes of MCNPX and three EM models. For example, in the Standard model, the photoelectron direction was sampled from the Gavrila-Sauter distribution, but the photoelectron moved in the same direction of the incident photons in the photoelectric process of Livermore and Penelope models. Using the same primary electron beam, the Standard and Livermore EM models of GATE and MCNPX showed similar output, but re-tuning of primary electron beam is needed for the Penelope model. PMID:24696804

  14. 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.

  15. Dosimetric validation of Monaco treatment planning system on an Elekta VersaHD linear accelerator.

    Science.gov (United States)

    Narayanasamy, Ganesh; Saenz, Daniel L; Defoor, Dewayne; Papanikolaou, Niko; Stathakis, Sotirios

    2017-11-01

    The purpose of this study is to perform dosimetric validation of Monaco treatment planning system version 5.1. The Elekta VersaHD linear accelerator with high dose rate flattening filter-free photon modes and electron energies was used in this study. The dosimetric output of the new Agility head combined with the FFF photon modes warranted this investigation into the dosimetric accuracy prior to clinical usage. A model of the VersaHD linac was created in Monaco TPS by Elekta using commissioned beam data including percent depth dose curves, beam profiles, and output factors. A variety of 3D conformal fields were created in Monaco TPS on a combined Plastic water/Styrofoam phantom and validated against measurements with a calibrated ion chamber. Some of the parameters varied including source to surface distance, field size, wedges, gantry angle, and depth for all photon and electron energies. In addition, a series of step and shoot IMRT, VMAT test plans, and patient plans on various anatomical sites were verified against measurements on a Delta 4 diode array. The agreement in point dose measurements was within 2% for all photon and electron energies in the homogeneous phantom and within 3% for photon energies in the heterogeneous phantom. The mean ± SD gamma passing rates of IMRT test fields yielded 93.8 ± 4.7% based on 2% dose difference and 2 mm distance-to-agreement criteria. Eight previously treated IMRT patient plans were replanned in Monaco TPS and five measurements on each yielded an average gamma passing rate of 95% with 6.7% confidence limit based on 3%, 3 mm gamma criteria. This investigation on dosimetric validation ensures accuracy of modeling VersaHD linac in Monaco TPS thereby improving patient safety. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  16. 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.

  17. Linear Economy Versus Circular Economy: A Comparative and Analyzer Study for Optimization of Economy for Sustainability

    Directory of Open Access Journals (Sweden)

    Sariatli Furkan

    2017-05-01

    Full Text Available Upon visiting the existing literature on the subject of linear vs. circular economy, this paper finds that, the blueprint of the current economy is hardly sustainable by using the comparative benchmarking method that drained from literature. The intrinsic mechanics of the linear economy, by relying on the wasteful take - make - dispose flow, is detrimental to the environment, cannot supply the growing populace of our planet with essential services and it naturally leads to strained profitability. Elements of a plausible solution to the challenges have been around for decades, although they have only recently been compiled in to the conceptual framework of circular economy. The core ideas of Circular Economy are elimination of waste by design, respect for the social, economic and natural environment and resource-conscious business conduct. Built on the backbone of these principles, the circular economy has demonstrated to deliver tangible benefits and viability to address the economic, environmental and social challenges of our days.

  18. Dose linearity and uniformity of Siemens ONCOR impression plus linear accelerator designed for step-and-shoot intensity-modulated radiation therapy

    Directory of Open Access Journals (Sweden)

    Bhangle Janhavi

    2007-01-01

    Full Text Available For step-and-shoot type delivery of intensity-modulated radiation therapy (IMRT, beam stability characteristics during the first few monitor units need to be investigated to ensure the planned dose delivery. This paper presents the study done for Siemens ONCOR impression plus linear accelerator before commissioning it for IMRT treatment. The beam stability for 6 and 15 MV in terms of dose monitor linearity, monitor unit stability and beam uniformity is investigated in this work. Monitor unit linearity is studied using FC65G chamber for the range 1-100 MU. The dose per MU is found to be linear for small monitor units down to 1 MU for both 6 and 15 MV beams. The monitor unit linearity is also studied with portal imaging device for the range 1-20 MU for 6 MV beam. The pixel values are within ±1σ confidence level up to 2 MU; for 1 MU, the values are within ±2σ confidence level. The flatness and symmetry analysis is done for both energies in the range of 1-10 MU with Kodak diagnostic films. The flatness and symmetry are found to be within ±3% up to 2 MU for 6 MV and up to 3 MU for 15 MV.

  19. Feasibility study of basic characterization of MAGAT polymer gel using CBCT attached in linear accelerator: Preliminary study

    Science.gov (United States)

    Sathiyaraj, P.; Samuel, E. James jebaseelan

    2018-01-01

    The aim of this study is to evaluate the methacrylic acid, gelatin and tetrakis (hydroxymethyl) phosphonium chloride gel (MAGAT) by cone beam computed tomography (CBCT) attached with modern linear accelerator. To compare the results of standard diagnostic computed tomography (CT) with CBCT, different parameters such as linearity, sensitivity and temporal stability were checked. MAGAT gel showed good linearity for both diagnostic CT and CBCT measurements. Sensitivity and temporal stability were also comparable with diagnostic CT measurements. In both the modalities, the sensitivity of the MAGAT increased to 4 days and decreased till the 10th day of post irradiation. Since all measurements (linearity, sensitivity and temporal stability) from diagnostic CT and CBCT were comparable, CBCT could be a potential tool for dose analysis study for polymer gel dosimeter.

  20. Responses to rotating linear acceleration vectors considered in relation to a model of the otolith organs. [human oculomotor response to transverse acceleration stress

    Science.gov (United States)

    Benson, A. J.; Barnes, G. R.

    1973-01-01

    Human subjects were exposed to a linear acceleration vector that rotated in the transverse plane of the skull without angular counterrotation. Lateral eye movements showed a sinusoidal change in slow phase velocity and an asymmetry or bias in the same direction as vector rotation. A model is developed that attributes the oculomotor response to otolithic mechanisms. It is suggested that the bias component is the manifestation of torsion of the statoconial plaque relative to the base of the utricular macula and that the sinusoidal component represents the translational oscillation of the statoconia. The model subsumes a hypothetical neural mechanism which allows x- and y-axis accelerations to be resolved. Derivation of equations of motion for the statoconial plaque in torsion and translation, which take into account forces acting in shear and normal to the macula, yield estimates of bias and sinusoidal components that are in qualitative agreement with the diverse experimental findings.

  1. Implementation of respiratory-gated VMAT on a Versa HD linear accelerator.

    Science.gov (United States)

    Snyder, Jeffrey E; Flynn, Ryan T; Hyer, Daniel E

    2017-09-01

    The accurate delivery of respiratory-gated volumetric modulated arc therapy (VMAT) treatment plans presents a challenge since the gantry rotation and collimator leaves must be repeatedly stopped and set into motion during each breathing cycle. In this study, we present the commissioning process for an Anzai gating system (AZ-733VI) on an Elekta Versa HD linear accelerator and make recommendations for successful clinical implementation. The commissioning tests include central axis dose consistency, profile consistency, gating beam-on/off delay, and comparison of gated versus nongated gamma pass rates for patient-specific quality assurance using four clinically commissioned photon energies: 6 MV, 6 FFF, 10 MV, and 10 FFF. The central axis dose constancy between gated and nongated deliveries was within 0.6% for all energies and the analysis of open field profiles for gated and nongated deliveries showed an agreement of 97.8% or greater when evaluated with a percent difference criteria of 1%. The measurement of the beam-on/off delay was done by evaluating images of a moving ball-bearing phantom triggered by the gating system and average beam-on delays of 0.22-0.29 s were observed. No measurable beam-off delay was present. Measurements of gated VMAT dose distributions resulted in decrements as high as 9% in the gamma passing rate as compared to nongated deliveries when evaluated against the planned dose distribution at 3%/3 mm. By decreasing the dose rate, which decreases the gantry speed during gated delivery, the gamma passing rates of gated and nongated treatments can be made equivalent. We present an empirically derived formula to limit the maximum dose rate during VMAT deliveries and show that by implementing a reduced dose rate, a gamma passing rate of greater than 95% (3%/3 mm) was obtained for all plan measurements. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of

  2. SU-E-T-74: Commissioning of the Elekta VersaHD Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y; Ding, K; Hobbs, R; McNutt, T; Wang, K [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, School of Medicine, Baltimore, MD (United States); Liang, X; Zhu, T [Department of Radiation Oncology, University of Pennsylvania, School of Medicine, Philadelphia, PA (United States)

    2014-06-01

    Purpose: To present the commissioning process of recently-released Elekta VersaHD linear accelerator, equipped with Agility 160-leaf multileaf collimator and flattening-filter free (FFF) photon modes. Methods: In addition to routine QA procedures, we adopted an EPID-based method to perform the table rotation and Winston-Lutz tests, and a novel multiradiation isocenter alignment check. The beam data acquired include photon percent-depth dose (PDD) of 6X, 6XFFF, 10X, 10XFFF, and 15X in the field size from 2×2 to 40×40cm{sup 2}, profiles, collimator and phantom scatter factors (Sc and Sp), wedge factor, electron (6, 9, 12, and 15MeV) PDD and profiles, cone and cutout factors, and virtual SSD. Validation measurements were carried out in water tank to evaluate the accuracy of beam modeling by the Pinnacle planning system. End-to-End test and IMRT QA were performed to validate the overall delivery accuracy. A theoretical model has also been used to extract the primary dose ratio and off-axis beam softening effects by fitting photon beam profile measurements. Results: The PDDs of FFF beams with field size 10×10cm{sup 2} at 10cm depth, 100cm SSD were intentionally adjusted within 1% of the non-FFF beams. The photon profiles of 30×30cm{sup 2} at 10cm depth between non-FFF and FFF beams are very different, OAR(10)=0.74 and 0.63, respectively, for 6XFFF and 10XFFF. The collimator and phantom scatter factors of FFF beam demonstrated smaller variation with field sizes. The EPID-based method demonstrated the maximum deviation between the table rotation axis and radiation isocenter is within 1mm, and the radiation isocenters are within 0.4mm relative to that of 6X. The validation measurement shows less than 2% deviation between the measurement and Pinnacle modeling for most of the test conditions. Conclusion: To the best of our knowledge, this is the first study reporting the Elekta VersaHD commissioning experience, which can be a valuable reference for the radiotherapy

  3. Accelerating Digital Mental Health Research From Early Design and Creation to Successful Implementation and Sustainment.

    Science.gov (United States)

    Mohr, David C; Lyon, Aaron R; Lattie, Emily G; Reddy, Madhu; Schueller, Stephen M

    2017-05-10

    Mental health problems are common and pose a tremendous societal burden in terms of cost, morbidity, quality of life, and mortality. The great majority of people experience barriers that prevent access to treatment, aggravated by a lack of mental health specialists. Digital mental health is potentially useful in meeting the treatment needs of large numbers of people. A growing number of efficacy trials have shown strong outcomes for digital mental health treatments. Yet despite their positive findings, there are very few examples of successful implementations and many failures. Although the research-to-practice gap is not unique to digital mental health, the inclusion of technology poses unique challenges. We outline some of the reasons for this gap and propose a collection of methods that can result in sustainable digital mental health interventions. These methods draw from human-computer interaction and implementation science and are integrated into an Accelerated Creation-to-Sustainment (ACTS) model. The ACTS model uses an iterative process that includes 2 basic functions (design and evaluate) across 3 general phases (Create, Trial, and Sustain). The ultimate goal in using the ACTS model is to produce a functioning technology-enabled service (TES) that is sustainable in a real-world treatment setting. We emphasize the importance of the service component because evidence from both research and practice has suggested that human touch is a critical ingredient in the most efficacious and used digital mental health treatments. The Create phase results in at least a minimally viable TES and an implementation blueprint. The Trial phase requires evaluation of both effectiveness and implementation while allowing optimization and continuous quality improvement of the TES and implementation plan. Finally, the Sustainment phase involves the withdrawal of research or donor support, while leaving a functioning, continuously improving TES in place. The ACTS model is a step

  4. Beam-based measurements of long-range transverse wakefields in the Compact Linear Collider main-linac accelerating structure

    Directory of Open Access Journals (Sweden)

    Hao Zha

    2016-01-01

    Full Text Available The baseline design of CLIC (Compact Linear Collider uses X-band accelerating structures for its main linacs. In order to maintain beam stability in multibunch operation, long-range transverse wakefields must be suppressed by 2 orders of magnitude between successive bunches, which are separated in time by 0.5 ns. Such strong wakefield suppression is achieved by equipping every accelerating structure cell with four damping waveguides terminated with individual rf loads. A beam-based experiment to directly measure the effectiveness of this long-range transverse wakefield and benchmark simulations was made in the FACET test facility at SLAC using a prototype CLIC accelerating structure. The experiment showed good agreement with the simulations and a strong suppression of the wakefields with an unprecedented minimum resolution of 0.1  V/(pC mm m.

  5. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Marocchino, A., E-mail: albz.uk@gmail.com [Dipartimento SBAI, “Sapienza” University of Rome and INFN-Roma 1, Rome (Italy); Massimo, F. [Dipartimento SBAI, “Sapienza” University of Rome and INFN-Roma 1, Rome (Italy); Rossi, A.R. [Dipartimento di Fisica, University of Milan and INFN-Milano, Milano (Italy); Chiadroni, E.; Ferrario, M. [INFN-LNF, Frascati (Italy)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Siemann, R.H. [ed.

    1998-07-01

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

  8. 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 ...

  9. Comparison of optimized ion acceleration from thin foils and low-density targets for linearly and circularly polarized laser pulses

    Science.gov (United States)

    Brantov, A. V.; Ksenofontov, P. A.; Bychenkov, V. Yu.

    2017-11-01

    A multiparameter comparative analysis of ion acceleration with linearly and circularly polarized relativistically intense laser pulses for solid-density thin foils and low-density planar targets was performed using 3D particle-in-cell (PIC) simulations. Ion acceleration optimization was studied with 3D PIC MANDOR over the laser energy range of three orders of magnitude from three hundred millijoules to three hundred joules in a femtosecond pulse. The optimum target thickness and density was found for a given energy of the laser pulse corresponding to the maximum energy of the accelerated ions. This allows deriving a dependence of the maximum ion energy on laser energy for the optimized solid or low-density targets. The advantage of a circularly polarized laser pulse for generating the most energetic ions was demonstrated, which happens for the regimes of volumetrically heated semitransparent solid foils (directed Coulomb explosion) and of synchronized ion acceleration by slow light from low-density targets. The dependence of the maximum ion energy on laser energy for the optimized targets and both linearly and circularly polarized femtosecond pulses demonstrates a sharper-than-square-root increase.

  10. Physical conditions for conducting radiobiological experiments in beams of accelerated particles with high linear energy transfer

    Science.gov (United States)

    Kudryashov, Y. I.; Marennyy, A. M.; Popov, V. I.; Aykhorn, K.; Ertsgreber, G.

    1974-01-01

    The design and construction of an accelerator to conduct radiobiological experiments is reported that uses aluminum filters to control the accelerated ion beam while preserving its stability, and a vacuum chamber to conduct the ion beam with the help of a collector through a lavsan exit port to the target. Depth distribution of the absorbed dose from a monodirectional ion beam is practically completely represented by the change in the energy spectrum of the biological object.

  11. Sustainable Transportation: Accelerating Widespread Adoption of Energy Efficient Vehicles & Fuels (Brochure)

    Energy Technology Data Exchange (ETDEWEB)

    2014-12-01

    While energy efficient transportation strategies have the potential to simultaneously slash oil consumption and reduce greenhouse gas (GHG) emissions, a truly sustainable solution will require more than just putting drivers behind the wheels of new fuel-efficient cars. As the only national laboratory dedicated 100% to renewable energy and energy efficiency, the National Renewable Energy Laboratory (NREL) accelerates widespread adoption of high-performance, low-emission, energy-efficient passenger and freight vehicles, as well as alternative fuels and related infrastructure. Researchers collaborate closely with industry, government, and research partners, using a whole-systems approach to design better batteries, drivetrains, and engines, as well as thermal management, energy storage, power electronic, climate control, alternative fuel, combustion, and emission systems. NREL's sustainable transportation research, development, and deployment (RD&D) efforts are not limited to vehicles, roads, and fueling stations. The lab also explores ways to save energy and reduce GHGs by integrating transportation technology advancements with renewable energy generation, power grids and building systems, urban planning and policy, and fleet operations.

  12. Determining the relationship between linear and rotational acceleration and MPS for different magnitudes of classified brain injury risk in ice hockey

    OpenAIRE

    Clark, J. Michio; Post, Andrew; Hoshizaki, Thomas Blaine; Gilchrist, M. D.

    2015-01-01

    Helmets have successfully decreased the incidence of traumatic brain injuries (TBI) in ice hockey, yet the incidence of concussions has essentially remained unchanged. Current ice hockey helmet certification standards use peak linear acceleration as the principal measuring helmet performance, however peak linear acceleration may not be an appropriate variable to evaluate risk at all magnitudes of brain injury. The purpose of this study is to determine the relationship between linear accelerat...

  13. 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

    2015-10-21

    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

  14. 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.

  15. Development of an automatic frequency control system for an X-band (=9300 MHz) RF electron linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Sungsu, E-mail: sscha@kaeri.re.kr [Nuclear Data Center, Korea Atomic Energy Research Institute (KAERI), Daejeon 34057 (Korea, Republic of); Kim, Yujong; Lee, Byung Cheol [Nuclear Data Center, Korea Atomic Energy Research Institute (KAERI), Daejeon 34057 (Korea, Republic of); Park, Hyung Dal [Radiation Technology eXcellence(RTX), Daejeon 34025 (Korea, Republic of); Lee, Seung Hyun [Department of Energy Science, Sungkyunkwan University(SKKU), Suwon 16419 (Korea, Republic of); Buaphad, Pikad [Nuclear Data Center, Korea Atomic Energy Research Institute (KAERI), Daejeon 34057 (Korea, Republic of); Radiation Technology eXcellence(RTX), Daejeon 34025 (Korea, Republic of); Accelerator and Nuclear Fusion Physical Engineering, University of Science and Technology(UST), Daejeon 34113 (Korea, Republic of)

    2017-05-21

    KAERI is developing a 6 MeV X-band radio frequency (RF) electron linear accelerator for medical purposes. The proposed X-band accelerator consists of an e-gun, an accelerating structure, two solenoid magnets, two steering magnets, a magnetron, a modulator, and an automatic frequency control (AFC) system. The accelerating structure of the component consists of oxygen-free high-conductivity copper (OFHC). Therefore, the ambient temperature changes the volume, and the resonance frequency of the accelerating structure also changes. If the RF frequency of a 9300 MHz magnetron and the resonance frequency of the accelerating structure do not match, it can degrade the performance. That is, it will decrease the output power, lower the beam current, decrease the X-ray dose rate, increase the reflection power, and result in unstable operation of the accelerator. Accelerator operation should be possible at any time during all four seasons. To prevent humans from being exposed to radiation when it is operated, the accelerator should also be operable through remote monitoring and remote control. Therefore, the AFC system is designed to meet these requirements; it is configured based on the concept of a phase-locked loop (PLL) model, which includes an RF section, an intermediate frequency (IF) [1-3] section, and a local oscillator (LO) section. Some resonance frequency controllers use a DC motor, chain, and potentiometer to store the position and tune the frequency [4,5]. Our AFC system uses a step motor to tune the RF frequency of the magnetron. The maximum tuning turn number of our magnetron frequency tuning shaft is ten. Since the RF frequency of our magnetron is 9300±25 MHz, it gives 5 MHz (∵±25 MHz/10 turns → 50 MHz/10 turns =5 MHz/turn) frequency tuning per turn. The rotation angle of our step motor is 0.72° per step and the total step number per one rotation is 360°/0.72°=500 steps. Therefore, the tuning range per step is 10 kHz/step (=5 MHz per turn/500 steps per

  16. Development of an automatic frequency control system for an X-band (=9300 MHz) RF electron linear accelerator

    Science.gov (United States)

    Cha, Sungsu; Kim, Yujong; Lee, Byung Cheol; Park, Hyung Dal; Lee, Seung Hyun; Buaphad, Pikad

    2017-05-01

    KAERI is developing a 6 MeV X-band radio frequency (RF) electron linear accelerator for medical purposes. The proposed X-band accelerator consists of an e-gun, an accelerating structure, two solenoid magnets, two steering magnets, a magnetron, a modulator, and an automatic frequency control (AFC) system. The accelerating structure of the component consists of oxygen-free high-conductivity copper (OFHC). Therefore, the ambient temperature changes the volume, and the resonance frequency of the accelerating structure also changes. If the RF frequency of a 9300 MHz magnetron and the resonance frequency of the accelerating structure do not match, it can degrade the performance. That is, it will decrease the output power, lower the beam current, decrease the X-ray dose rate, increase the reflection power, and result in unstable operation of the accelerator. Accelerator operation should be possible at any time during all four seasons. To prevent humans from being exposed to radiation when it is operated, the accelerator should also be operable through remote monitoring and remote control. Therefore, the AFC system is designed to meet these requirements; it is configured based on the concept of a phase-locked loop (PLL) model, which includes an RF section, an intermediate frequency (IF) [1-3] section, and a local oscillator (LO) section. Some resonance frequency controllers use a DC motor, chain, and potentiometer to store the position and tune the frequency [4,5]. Our AFC system uses a step motor to tune the RF frequency of the magnetron. The maximum tuning turn number of our magnetron frequency tuning shaft is ten. Since the RF frequency of our magnetron is 9300±25 MHz, it gives 5 MHz (∵±25 MHz/10 turns → 50 MHz/10 turns =5 MHz/turn) frequency tuning per turn. The rotation angle of our step motor is 0.72° per step and the total step number per one rotation is 360°/0.72°=500 steps. Therefore, the tuning range per step is 10 kHz/step (=5 MHz per turn/500 steps per

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

    DEFF Research Database (Denmark)

    Riis, H. L.; Zimmermann, S. J.; Hjelm-Hansen, M.

    2013-01-01

    -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...

  18. Spatial Estimation of Accelerated Stimuli Is Based on a Linear Extrapolation of First-Order Information.

    Science.gov (United States)

    Bennett, Simon J; Benguigui, Nicolas

    2016-03-01

    We examined spatial estimation of accelerating objects (-8, -4, 0, +4, or +8 deg/s(2)) during occlusion (600, 1,000 ms) in a spatial prediction motion task. Multiple logistic regression indicated spatial estimation was influenced by these factors such that participants estimated objects with positive acceleration to reappear behind less often than those with negative acceleration, and particularly after the longer occlusion. Individual-participant logistic regressions indicated spatial estimation was better predicted by a first-order extrapolation of the occluded object motion based on pre-occlusion velocity rather than a second-order extrapolation that took account of object acceleration. We suggest a general principle of extrapolation is involved in prediction motion tasks whereby there is a contraction of the variable of interest (i.e., displacement in spatial prediction motion and time in temporal prediction motion). Such an approach to extrapolation could be advantageous as it would offer participants better opportunity to correct for an initial estimation error.

  19. The International Linear Collider Technical Design Report - Volume 3.I: Accelerator R&D in the Technical Design Phase

    CERN Document Server

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

    2013-01-01

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

  20. Convergence of Linear Acceleration and Yaw Rotation Signals on non-Eye Movement Neurons in the Vestibular Nucleus of Macaques.

    Science.gov (United States)

    Newlands, Shawn D; Abbatematteo, Ben; Wei, Min; Carney, Laurel H; Luan, Hongge

    2017-10-04

    Roughly half of all vestibular nucleus neurons without eye movement sensitivity respond to both angular rotation and linear acceleration. Linear acceleration signals arise from otolith organs and rotation signals arise from semicircular canals. In the vestibular nerve, these signals are carried by different afferents. Vestibular nucleus neurons represent the first point of convergence for these distinct sensory signals. This study systematically evaluated how rotational and translational signals interact in single neurons in the vestibular nuclei: multisensory integration at the first opportunity for convergence between these two independent vestibular sensory signals. Single-unit recordings were made from the vestibular nuclei of awake macaques during yaw rotation, translation in the horizontal plane, and combinations of rotation and translation at different frequencies. The overall response magnitude of the combined translation and rotation was generally less than the sum of the magnitudes in responses to the stimuli applied independently. However, we found that under conditions in which the peaks of the rotational and translational responses were coincident, these signals were approximately additive. With presentation of rotation and translation at different frequencies, rotation was attenuated more than translation, regardless of which was at a higher frequency. These data suggest a non-linear interaction between these two sensory modalities in the vestibular nuclei, in which coincident peak responses are proportionally stronger than other, off-peak interactions. These results are similar to those reported for other forms of multisensory integration, such as audio-visual integration in the superior colliculus. Copyright © 2017, Journal of Neurophysiology.

  1. Measurement of depth-dose of linear accelerator and simulation by use of Geant4 computer code.

    Science.gov (United States)

    Sardari, D; Maleki, R; Samavat, H; Esmaeeli, A

    2010-01-01

    Radiation therapy is an established method of cancer treatment. New technologies in cancer radiotherapy need a more accurate computation of the dose delivered in the radiotherapy treatment plan. This study presents some results of a Geant4-based application for simulation of the absorbed dose distribution given by a medical linear accelerator (LINAC). The LINAC geometry is accurately described in the Monte Carlo code with use of the accelerator manufacturer's specifications. The capability of the software for evaluating the dose distribution has been verified by comparisons with measurements in a water phantom; the comparisons were performed for percentage depth dose (PDD) and profiles for various field sizes and depths, for a 6-MV electron beam. Experimental and calculated dose values were in good agreement both in PDD and in transverse sections of the water phantom.

  2. Study of the electronics architecture for the mechanical stabilisation of the quadrupoles of the CLIC linear accelerator

    CERN Document Server

    Artoos, K; Fernandez Carmona, P; Guinchard, M; Hauviller, C; Janssens, S; Kuzmin, A; Slaathaug, A

    2010-01-01

    To reach a sufficient luminosity, the transverse beam sizes and emittances in future linear particle accelerators should be reduced to the nanometer level. Mechanical stabilisation of the quadrupole magnets is of the utmost importance for this. The piezo actuators used for this purpose can also be used to make fast incremental orientation adjustments with a nanometer resolution. The main requirements for the CLIC stabilisation electronics is a robust, low noise, low delay, high accuracy and resolution, low band and radiation resistant feedback control loop. Due to the high number of controllers (about 4000) a cost optimization should also be made. Different architectures are evaluated for a magnet stabilisation prototype, including the sensors type and configuration, partition between software and hardware for control algorithms, and optimization of the ADC/DAC converters. The controllers will be distributed along the 50 km long accelerator and a communication bus should allow external control. Furthermore, o...

  3. Effects of initial electron beam parameters of a linear accelerator on the properties of bremsstrahlung radiation in a radiotherapy setting

    Science.gov (United States)

    Gorlachev, G. E.; Polozov, S. M.; Dalechina, A. V.; Ksenofontov, A. I.; Kistenev, A. V.

    2016-12-01

    The dependence of the initial electron-beam parameters on absorbed dose distributions have been investigated using a CyberKnife radiotherapy accelerator (Accuray, United States). To describe the initial electron-beam characteristics, simulations of the linear electron accelerator are performed and the electron distributions in the beam of a linac output are analyzed. The radial distributions of electrons are assumed exponential, whereas the energy electron distributions are approximated by monoenergetic and rectangular spectra. There is no significant dependence of depth-dose curves in a phantom on the shape of the electron beam. Importantly, a clear dependence of the radiation field profile on the size of the electron beam is observed not just in the penumbra region, but also in the open part.

  4. Comment on “Beamstrahlung considerations in laser-plasma-accelerator-based linear colliders”

    Directory of Open Access Journals (Sweden)

    Valeri Lebedev

    2013-10-01

    Full Text Available Schroeder, Esarey, Geddes, Benedetti, and Leemans [Phys. Rev. ST Accel. Beams 13, 101301 (2010PRABFM1098-440210.1103/PhysRevSTAB.13.101301 and Phys. Rev. ST Accel. Beams 15, 051301 (2012PRABFM1098-440210.1103/PhysRevSTAB.15.051301] have proposed a set of parameters for a TeV-scale collider based on plasma wakefield accelerator principles. In particular, it is sugested that the luminosities greater than 10^{34}  cm^{-2} s^{-1} are attainable for an electron-positron collider. In this Comment we dispute this set of parameters on the basis of first principles. The interactions of accelerating beam with plasma impose fundamental limitations on beam properties and, thus, on attainable luminosity values.

  5. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Viera, Wilson J.; Ono, Shizuca; Claro, Luiz H.; Dias, Artur F. [Centro Tecnico Aeroespacial (IEAv/CTA), Sao Jose dos Campos, SP (Brazil). Inst. de Estudos Avancados], e-mail: wjvieira@ieav.cta.br, e-mail: shizuca@ieav.cta.br, e-mail: luizhenu@ieav.cta.br, e-mail: arturf@ieav.cta.br

    2001-07-01

    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)

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

    Science.gov (United States)

    Park, Bum-Sik; Hong, In-Seok; Jang, Ji-Ho; Jin, Hyunchang; Choi, Sukjin; Kim, Yonghwan

    2016-02-01

    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.

  8. 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.

  9. Competitive space demand accelerator and its impacts on importance and sustainability of competitive advantages

    Directory of Open Access Journals (Sweden)

    Robert Zich

    2013-01-01

    Full Text Available A determined effort of companies to improve their potential of success-ability through a development of their own competitiveness is very significantly reflected in the nature of their competitive environment. A question can be asked: what changes are introduced and what their mechanism is. The main objective of this article has been to define a theoretical background to a principle of a competitive space demands accelerator and its impacts on deterioration and sustainability of competitive advantages. The methodology used is based upon a success-ability concept. The success-ability concept describes behavior of companies in the way which – from the point of an approach to competitiveness development – is able to identify specific features, frequently neglected by conventional approaches. Presented paper defines a mechanism of growing level of demands of competitive environment especially in the context of three key factors – company, its competitors and customers and their needs. The paper explains a paradox - an endeavor to gain higher level of advantage results in a rapid deterioration of new, achieved level of such advantage, in the sense of a lead over competitors, practically very soon after securing of such advantage.

  10. 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.

  11. 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.

  12. Acceleration of Linear Finite-Difference Poisson-Boltzmann Methods on Graphics Processing Units.

    Science.gov (United States)

    Qi, Ruxi; Botello-Smith, Wesley M; Luo, Ray

    2017-07-11

    Electrostatic interactions play crucial roles in biophysical processes such as protein folding and molecular recognition. Poisson-Boltzmann equation (PBE)-based models have emerged as widely used in modeling these important processes. Though great efforts have been put into developing efficient PBE numerical models, challenges still remain due to the high dimensionality of typical biomolecular systems. In this study, we implemented and analyzed commonly used linear PBE solvers for the ever-improving graphics processing units (GPU) for biomolecular simulations, including both standard and preconditioned conjugate gradient (CG) solvers with several alternative preconditioners. Our implementation utilizes the standard Nvidia CUDA libraries cuSPARSE, cuBLAS, and CUSP. Extensive tests show that good numerical accuracy can be achieved given that the single precision is often used for numerical applications on GPU platforms. The optimal GPU performance was observed with the Jacobi-preconditioned CG solver, with a significant speedup over standard CG solver on CPU in our diversified test cases. Our analysis further shows that different matrix storage formats also considerably affect the efficiency of different linear PBE solvers on GPU, with the diagonal format best suited for our standard finite-difference linear systems. Further efficiency may be possible with matrix-free operations and integrated grid stencil setup specifically tailored for the banded matrices in PBE-specific linear systems.

  13. A model for preemptive maintenance of medical linear accelerators-predictive maintenance.

    Science.gov (United States)

    Able, Charles M; Baydush, Alan H; Nguyen, Callistus; Gersh, Jacob; Ndlovu, Alois; Rebo, Igor; Booth, Jeremy; Perez, Mario; Sintay, Benjamin; Munley, Michael T

    2016-03-10

    Unscheduled accelerator downtime can negatively impact the quality of life of patients during their struggle against cancer. Currently digital data accumulated in the accelerator system is not being exploited in a systematic manner to assist in more efficient deployment of service engineering resources. The purpose of this study is to develop an effective process for detecting unexpected deviations in accelerator system operating parameters and/or performance that predicts component failure or system dysfunction and allows maintenance to be performed prior to the actuation of interlocks. The proposed predictive maintenance (PdM) model is as follows: 1) deliver a daily quality assurance (QA) treatment; 2) automatically transfer and interrogate the resulting log files; 3) once baselines are established, subject daily operating and performance values to statistical process control (SPC) analysis; 4) determine if any alarms have been triggered; and 5) alert facility and system service engineers. A robust volumetric modulated arc QA treatment is delivered to establish mean operating values and perform continuous sampling and monitoring using SPC methodology. Chart limits are calculated using a hybrid technique that includes the use of the standard SPC 3σ limits and an empirical factor based on the parameter/system specification. There are 7 accelerators currently under active surveillance. Currently 45 parameters plus each MLC leaf (120) are analyzed using Individual and Moving Range (I/MR) charts. The initial warning and alarm rule is as follows: warning (2 out of 3 consecutive values ≥ 2σ hybrid) and alarm (2 out of 3 consecutive values or 3 out of 5 consecutive values ≥ 3σ hybrid). A customized graphical user interface provides a means to review the SPC charts for each parameter and a visual color code to alert the reviewer of parameter status. Forty-five synthetic errors/changes were introduced to test the effectiveness of our initial chart limits. Forty

  14. Review of linear optics measurement and correction for charged particle accelerators

    Science.gov (United States)

    Tomás, Rogelio; Aiba, Masamitsu; Franchi, Andrea; Iriso, Ubaldo

    2017-05-01

    Measurement and correction of charged particle beam optics have been a major concern since the advent of strong focusing synchrotron accelerators. Traditionally, particle colliders have led the development of optics control based on turn-by-turn beam centroid measurements, while lepton storage rings have focused on closed-orbit-response matrix techniques. Recently, considerable efforts are being invested in comparing these techniques at different synchrotron radiation sources and colliders. An emerging class of less invasive techniques based on the optimization of performance-related observables is demonstrating a great potential. In this paper, a review of existing techniques is presented highlighting comparisons, relative merits and limitations.

  15. High Power Klystrons: Theory and Practice at the Stanford Linear Accelerator CenterPart I

    Energy Technology Data Exchange (ETDEWEB)

    Caryotakis, G.

    2004-12-15

    This is Part I of a two-part report on design and manufacturing methods used at SLAC to produce accelerator klystrons. Chapter 1 begins with the history and applications for klystrons, in both of which Stanford University was extensively involved. The remaining chapters review the theory of klystron operation, derive the principal formulae used in their design, and discuss the assumptions that they involve. These formulae are subsequently used in small-signal calculations of the frequency response of a particular klystron, whose performance is also simulated by two different computer codes. The results of calculations and simulations are compared to the actual performance of the klystron.

  16. Photoneutron Flux Measurement via Neutron Activation Analysis in a Radiotherapy Bunker with an 18 MV Linear Accelerator

    Directory of Open Access Journals (Sweden)

    Çeçen Yiğit

    2017-01-01

    Full Text Available In cancer treatment, high energy X-rays are used which are produced by linear accelerators (LINACs. If the energy of these beams is over 8 MeV, photonuclear reactions occur between the bremsstrahlung photons and the metallic parts of the LINAC. As a result of these interactions, neutrons are also produced as secondary radiation products (γ,n which are called photoneutrons. The study aims to map the photoneutron flux distribution within the LINAC bunker via neutron activation analysis (NAA using indium-cadmium foils. Irradiations made at different gantry angles (0°, 90°, 180° and 270° with a total of 91 positions in the Philips SLI-25 linear accelerator treatment room and location-based distribution of thermal neutron flux was obtained. Gamma spectrum analysis was carried out with high purity germanium (HPGe detector. Results of the analysis showed that the maximum neutron flux in the room occurred at just above of the LINAC head (1.2x105 neutrons/cm2.s which is compatible with an americium-beryllium (Am-Be neutron source. There was a 90% decrease of flux at the walls and at the start of the maze with respect to the maximum neutron flux. And, just in front of the LINAC door, inside the room, neutron flux was measured less than 1% of the maximum.

  17. Photoneutron Flux Measurement via Neutron Activation Analysis in a Radiotherapy Bunker with an 18 MV Linear Accelerator

    Science.gov (United States)

    Çeçen, Yiğit; Gülümser, Tuğçe; Yazgan, Çağrı; Dapo, Haris; Üstün, Mahmut; Boztosun, Ismail

    2017-09-01

    In cancer treatment, high energy X-rays are used which are produced by linear accelerators (LINACs). If the energy of these beams is over 8 MeV, photonuclear reactions occur between the bremsstrahlung photons and the metallic parts of the LINAC. As a result of these interactions, neutrons are also produced as secondary radiation products (γ,n) which are called photoneutrons. The study aims to map the photoneutron flux distribution within the LINAC bunker via neutron activation analysis (NAA) using indium-cadmium foils. Irradiations made at different gantry angles (0°, 90°, 180° and 270°) with a total of 91 positions in the Philips SLI-25 linear accelerator treatment room and location-based distribution of thermal neutron flux was obtained. Gamma spectrum analysis was carried out with high purity germanium (HPGe) detector. Results of the analysis showed that the maximum neutron flux in the room occurred at just above of the LINAC head (1.2x105 neutrons/cm2.s) which is compatible with an americium-beryllium (Am-Be) neutron source. There was a 90% decrease of flux at the walls and at the start of the maze with respect to the maximum neutron flux. And, just in front of the LINAC door, inside the room, neutron flux was measured less than 1% of the maximum.

  18. 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. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. Advances in Normal Conducting Accelerator Technology from the X-Band Linear Collider Program

    CERN Document Server

    Adolphsen, Chris

    2005-01-01

    In the early 1990's, groups at SLAC and KEK began dedicated development of X-band (11.4 GHz) rf technology for a next generation, TeV-scale linear collider. The choice of a relatively high frequency, four times that of the SLAC 50 GeV Linac, was motivated by the cost benefits of having lower rf energy per pulse (hence fewer rf components) and reasonable efficiencies at high gradients (hence shorter linacs). However, to realize such savings requires operation at gradients and peak powers much higher than that hitherto achieved. During the past 15 years, these challenges were met through innovations on several fronts, and resulted in a viable rf system design for a linear collider. This paper reviews these achievements, which include developments in the generation and transport of high power rf, and new insights into high gradient limitations.

  20. Simultaneous external and internal stabilization of linear systems with input saturation and non-input-additive sustained disturbances

    NARCIS (Netherlands)

    Wang, Xu; Saberi, Ali; Grip, H°avard Fjær; Stoorvogel, Antonie Arij

    2012-01-01

    In this paper, we study simultaneous external and internal stabilization of the linear system under input saturation and non-input additive sustained disturbances. For systems that are asymptotic null controllable with bounded control, it is shown that a nonlinear dynamic feedback controller can be

  1. Is it sufficient to repeat LINEAR accelerator stereotactic radiosurgery in choroidal melanoma?

    Science.gov (United States)

    Furdova, A; Horkovicova, K; Justusova, P; Sramka, M

    One day session LINAC based stereotactic radiosurgery (SRS) at LINAC accelerator is a method of "conservative" attitude to treat the intraocular malignant uveal melanoma. We used model Clinac 600 C/D Varian (system Aria, planning system Corvus version 6.2 verification IMRT OmniPro) with 6 MeV X by rigid immobilization of the eye to the Leibinger frame. The stereotactic treatment planning after fusion of CT and MRI was optimized according to the critical structures (lens, optic nerve, also lens and optic nerve at the contralateral side, chiasm). The first plan was compared and the best plan was applied for therapy at C LINAC accelerator. The planned therapeutic dose was 35.0 Gy by 99 % of DVH (dose volume histogram). In our clinical study in the group of 125 patients with posterior uveal melanoma treated with SRS, in 2 patients (1.6 %) was repeated SRS indicated. Patient age of the whole group ranged from 25 to 81 years with a median of 54 TD was 35.0 Gy. In 2 patients after 5 year interval after stereotactic radiosurgery for uveal melanoma stage T1, the tumor volume increased to 50 % of the primary tumor volume and repeated SRS was necessary. To find out the changes in melanoma characteristics after SRS in long term interval after irradiation is necessary to follow up the patient by an ophthalmologist regularly. One step LINAC based stereotactic radiosurgery with a single dose 35.0 Gy is one of treatment options to treat T1 to T3 stage posterior uveal melanoma and to preserve the eye globe. In some cases it is possible to repeat the SRS after more than 5 year interval (Fig. 8, Ref. 23).

  2. 3-D Model of Broadband Emission from Supernova Remnants Undergoing Non-linear Diffusive Shock Acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Shiu-Hang; Kamae, Tuneyoshi; Ellison, Donald C.

    2008-07-02

    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 occurring 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 develop a flexible platform, which can be generalized to include effects such as MFA, and which can be easily adapted to various SNR environments, including Type Ia SNRs, which explode in a constant density medium, and Type II SNRs, which explode in a pre-supernova wind. When applied to a specific SNR, our model will predict cosmic-ray spectra and multi-wavelength morphology in projected images for instruments with varying spatial and spectral resolutions. We show examples of these spectra and images and emphasize the importance of measurements in the hard X-ray, GeV, and TeV gamma-ray bands for investigating key ingredients in the acceleration mechanism, and for deducing whether or not TeV emission is produced by IC from electrons or pion-decay from protons.

  3. Non-LTE line-blanketed model atmospheres of hot stars. 1: Hybrid complete linearization/accelerated lambda iteration method

    Science.gov (United States)

    Hubeny, I.; Lanz, T.

    1995-01-01

    A new munerical method for computing non-Local Thermodynamic Equilibrium (non-LTE) model stellar atmospheres is presented. The method, called the hybird complete linearization/accelerated lambda iretation (CL/ALI) method, combines advantages of both its constituents. Its rate of convergence is virtually as high as for the standard CL method, while the computer time per iteration is almost as low as for the standard ALI method. The method is formulated as the standard complete lineariation, the only difference being that the radiation intensity at selected frequency points is not explicity linearized; instead, it is treated by means of the ALI approach. The scheme offers a wide spectrum of options, ranging from the full CL to the full ALI method. We deonstrate that the method works optimally if the majority of frequency points are treated in the ALI mode, while the radiation intensity at a few (typically two to 30) frequency points is explicity linearized. We show how this method can be applied to calculate metal line-blanketed non-LTE model atmospheres, by using the idea of 'superlevels' and 'superlines' introduced originally by Anderson (1989). We calculate several illustrative models taking into accont several tens of thosands of lines of Fe III to Fe IV and show that the hybrid CL/ALI method provides a robust method for calculating non-LTE line-blanketed model atmospheres for a wide range of stellar parameters. The results for individual stellar types will be presented in subsequent papers in this series.

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

    Directory of Open Access Journals (Sweden)

    Keyvan Jabbari

    2012-03-01

    Full Text Available Introduction Intensity Modulated Radiation Therapy (IMRT 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 IMRT is a topic of interest for researchers. This article is about the various steps of planning and quality control of Siemens linear accelerators for IMRT, 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. Materials and Methods This project was carried out in Isfahan Milad hospital which has two Siemens ONCOR linear accelerators. Both accelerators are equipped with Multi-Leaf Collimators (MLC which enables us to perform IMRT 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, MLC, 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. Results The results of the experiments in various steps have been acceptable according to the standard protocols. The calibration of MLC and evaluation of the leakage through the leaves of MLC 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, between 85 and 90% of the points had such an agreement with IMRT delivery. Conclusion

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

    Science.gov (United States)

    Kry, Stephen F; Johnson, Jennifer L; White, R Allen; Howell, Rebecca M; Kudchadker, Rajat J; Gillin, Michael T

    2011-01-01

    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. 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. 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. 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.

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

    Directory of Open Access Journals (Sweden)

    Zhou Lin

    2016-03-01

    Full Text Available 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/μs 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.

  7. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. The statistical analysis of failure of a MEVATRON77 DX67 linear accelerator over a ten year period

    CERN Document Server

    Aoyama, H; Tahara, S; Uno, H; Kadohisa, S; Azuma, Y; Nakagiri, Y; Hiraki, Y

    2003-01-01

    A linear accelerator (linac) takes a leading role in radiation therapy. A linac consists of complicated main parts and systems and it is required that highly accurate operational procedures should be maintained. Operational failure occurs for various reasons. In this report, the failure occurrences of one linac over a ten year period were recorded and analyzed. The subject model was a MEVATRON77 DX67 (Siemens, Inc). The failure rate for each system, the form classification of the contents of failure, the operation situation at the time of failure, and the average performance life of the main parts were totaled. Moreover, the relation between the number of therapies that patients received (operating efficiency) and the failure rate within that number and the relation between environment (temperature and humidity) and the failure rate attributed to other systems were analyzed. In this report, irradiation interruption was also included with situations where treatment was unable to begin in total for the number o...

  9. 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. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  10. 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.

  11. Data Normalization to Accelerate Training for Linear Neural Net to Predict Tropical Cyclone Tracks

    Directory of Open Access Journals (Sweden)

    Jian Jin

    2015-01-01

    Full Text Available When pure linear neural network (PLNN is used to predict tropical cyclone tracks (TCTs in South China Sea, whether the data is normalized or not greatly affects the training process. In this paper, min.-max. method and normal distribution method, instead of standard normal distribution, are applied to TCT data before modeling. We propose the experimental schemes in which, with min.-max. method, the min.-max. value pair of each variable is mapped to (−1, 1 and (0, 1; with normal distribution method, each variable’s mean and standard deviation pair is set to (0, 1 and (100, 1. We present the following results: (1 data scaled to the similar intervals have similar effects, no matter the use of min.-max. or normal distribution method; (2 mapping data to around 0 gains much faster training speed than mapping them to the intervals far away from 0 or using unnormalized raw data, although all of them can approach the same lower level after certain steps from their training error curves. This could be useful to decide data normalization method when PLNN is used individually.

  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. [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.

  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. © 2012 American Institute of Physics

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

    Directory of Open Access Journals (Sweden)

    J. W. Elmer

    2001-05-01

    Full Text Available 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

  16. Development of new S-band RF window for stable high-power operation in linear accelerator RF system

    Science.gov (United States)

    Joo, Youngdo; Lee, Byung-Joon; Kim, Seung-Hwan; Kong, Hyung-Sup; Hwang, Woonha; Roh, Sungjoo; Ryu, Jiwan

    2017-09-01

    For stable high-power operation, a new RF window is developed in the S-band linear accelerator (Linac) RF systems of the Pohang Light Source-II (PLS-II) and the Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL). The new RF window is designed to mitigate the strength of the electric field at the ceramic disk and also at the waveguide-cavity coupling structure of the conventional RF window. By replacing the pill-box type cavity in the conventional RF window with an overmoded cavity, the electric field component perpendicular to the ceramic disk that caused most of the multipacting breakdowns in the ceramic disk was reduced by an order of magnitude. The reduced electric field at the ceramic disk eliminated the Ti-N coating process on the ceramic surface in the fabrication procedure of the new RF window, preventing the incomplete coating from spoiling the RF transmission and lowering the fabrication cost. The overmoded cavity was coupled with input and output waveguides through dual side-wall coupling irises to reduce the electric field strength at the waveguide-cavity coupling structure and the possibility of mode competitions in the overmoded cavity. A prototype of the new RF window was fabricated and fully tested with the Klystron peak input power, pulse duration and pulse repetition rate of 75 MW, 4.5 μs and 10 Hz, respectively, at the high-power test stand. The first mass-produced new RF window installed in the PLS-II Linac is running in normal operation mode. No fault is reported to date. Plans are being made to install the new RF window to all S-band accelerator RF modules of the PLS-II and PAL-XFEL Linacs. This new RF window may be applied to the output windows of S-band power sources like Klystron as wells as the waveguide windows of accelerator facilities which operate in S-band.

  17. Water, sanitation and hygiene for accelerating and sustaining progress on neglected tropical diseases: a new Global Strategy 2015-20.

    Science.gov (United States)

    Boisson, Sophie; Engels, Dirk; Gordon, Bruce A; Medlicott, Kate O; Neira, Maria P; Montresor, Antonio; Solomon, Anthony W; Velleman, Yael

    2016-03-01

    Neglected tropical diseases (NTDs) affect over 1 billion people. Safe water, sanitation and hygiene (WASH) contribute to prevention and management of most NTDs. Linking WASH and NTD interventions has potential to impact on multiple NTDs and can help secure sustainable and equitable progress towards universal access to WASH. The need to address the determinants of NTDs has been acknowledged. In response, WHO has published a new Global Strategy: 'Water, Sanitation and Hygiene for accelerating and sustaining progress on Neglected Tropical Diseases'. The Strategy focuses on cross-cutting actions that benefit disease control and care efforts, and strengthen health systems. Implementation of the strategy and the accompanying action plan can help ensure that the health and development agenda leaves no one behind. © The Author 2016. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. X-ray acoustic computed tomography with pulsed x-ray beam from a medical linear accelerator.

    Science.gov (United States)

    Xiang, Liangzhong; Han, Bin; Carpenter, Colin; Pratx, Guillem; Kuang, Yu; Xing, Lei

    2013-01-01

    The feasibility of medical imaging using a medical linear accelerator to generate acoustic waves is investigated. This modality, x-ray acoustic computed tomography (XACT), has the potential to enable deeper tissue penetration in tissue than photoacoustic tomography via laser excitation. Short pulsed (μs-range) 10 MV x-ray beams with dose-rate of approximately 30 Gy∕min were generated from a medical linear accelerator. The acoustic signals were collected with an ultrasound transducer (500 KHz central frequency) positioned around an object. The transducer, driven by a computer-controlled step motor to scan around the object, detected the resulting acoustic signals in the imaging plane at each scanning position. A pulse preamplifier, with a bandwidth of 20 KHz-2 MHz at -3 dB, and switchable gains of 40 and 60 dB, received the signals from the transducer and delivered the amplified signals to a secondary amplifier. The secondary amplifier had bandwidth of 20 KHz-30 MHz at -3 dB, and a gain range of 10-60 dB. Signals were recorded and averaged 128 times by an oscilloscope. A sampling rate of 100 MHz was used to record 2500 data points at each view angle. One set of data incorporated 200 positions as the receiver moved 360°. The x-ray generated acoustic image was then reconstructed with the filtered back projection algorithm. The x-ray generated acoustic signals were detected from a lead rod embedded in a chicken breast tissue. The authors found that the acoustic signal was proportional to the x-ray dose deposition, with a correlation of 0.998. The two-dimensional XACT images of the lead rod embedded in chicken breast tissue were found to be in good agreement with the shape of the object. The first x-ray acoustic computed tomography image is presented. The new modality may be useful for a number of applications, such as providing the location of a fiducial, or monitoring x-ray dose distribution during radiation therapy. Although much work is needed to improve the

  19. A Postulate for Accelerated Implementation of Sustainable Development Goals and Principles

    Science.gov (United States)

    Kassenberg, Andrzej

    2017-12-01

    The last 30-year period has been increasingly important for sustainable development, as is evidenced by the UN's announcement of 17 Sustainable Development Goals to be achieved by 2030. However, many megatrends continue to progress in the direction opposite to that meeting the needs of sustainable development. For the Earth and human civilisation to be protected, it is necessary for a new approach to be developed - a new order that might be termed the civilization/economics of enough, or of moderation. However, convincing societies, including that of Poland, in regard to the benefits of addressing the challenges sustainable development poses is not an easy task; even though a redirecting of the economy and of society along new paths will bring measurable benefits capable of compensating for the costs of transformation.

  20. High Current Linear Accelerators.

    Science.gov (United States)

    1985-10-01

    8217 ’_ ]’ % :: ’ , .% % ,-,,,.’ .’,.’.’,.’ .. ,, ,.. ,." ’,.-.’ . .. ,.-....-.- _ .... ".- ’ V - In . (2) b a 2 OPDC a In these equations YD and D are the usual relativistic factors

  1. Single-centre experience of stereotactic radiosurgery and fractionated stereotactic radiotherapy for prolactinomas with the linear accelerator.

    Science.gov (United States)

    Wilson, Peter J; Williams, Janet Rosemary; Smee, Robert Ian

    2015-06-01

    Primary management of prolactinomas is usually medical, with surgery a secondary option where necessary. This study is a review of a single centre's experience with focused radiotherapy where benefit was not gained by medical or surgical approaches. Radiotherapy as an alternative and adjuvant treatment for prolactinomas has been performed at our institution with the linear accelerator since 1990. We present a retrospective review of 13 patients managed with stereotactic radiosurgery (SRS) and 5 managed with fractionated stereotactic radiotherapy (FSRT), as well as 5 managed with conventional radiotherapy, at the Prince of Wales Hospital. Patients with a histopathologically diagnosed prolactinoma were eligible. Those patients who had a confirmed pathological diagnosis of prolactinoma following surgical intervention, a prolactin level elevated above 500 μg/L, or a prolactin level persistently elevated above 200 μg/L with exclusion of other causes were represented in this review. At the end of documented follow-up (SRS median 6 years, FSRT median 2 years), no SRS patients showed an increase in tumour volume. After FSRT, 1 patient showed an increase in size, 2 showed a decrease in size and 2 patients showed no change. Prolactin levels trended towards improvement after SRS and FSRT, but no patients achieved the remission level of stereotactic radiation were very low in this series. © 2014 The Royal Australian and New Zealand College of Radiologists.

  2. Environmental Assessment for US Department of Energy support of an Iowa State University Linear Accelerator Facility at Ames, Iowa

    Energy Technology Data Exchange (ETDEWEB)

    1990-05-01

    The proposed Department of Energy (DOE) action is financial and technical support of construction and initial operation of an agricultural commodity irradiator (principally for meat), employing a dual mode electron beam generator capable of producing x-rays, at the Iowa State University Linear Accelerator located at Ames, Iowa. The planned pilot commercial-scale facility would be used for the following activities: conducting irradiation research on agricultural commodities, principally meats; in the future, after the pilot phase, as schedules permit, possibly conducting research on other, non-edible materials; evaluating effects of irradiation on nutritional and sensory quality of agricultural products; demonstrating the efficiency of the process to control or eliminate pathogens, and/or to prolong the commodities' post-harvest shelf-life via control or elimination of bacteria, fungi, and/or insects; providing information to the public on the benefits, safety and risks of irradiated agricultural commodities; determining consumer acceptability of the irradiated products; providing data for use by regulatory agencies in developing protocols for various treatments of Iowa agricultural commodities; and training operators, maintenance and quality control technicians, scientists, engineers, and staff of regulatory agencies in agricultural commodity irradiation technology. 14 refs., 5 figs.

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-08-01

    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).

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

    Science.gov (United States)

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

    2011-09-30

    A new-generation low-energy linear accelerator (UNIQUE) was introduced in the clinical arena during 2009 by Varian Medical Systems. The world's first UNIQUE was installed at Oncology Institute of Southern Switzerland and put into clinical operation in June 2010. The aim of the present contribution was to report experience about its commissioning and first year results from clinical operation. Commissioning data, beam characteristics and the modeling into the treatment planning system were summarized. Imaging system of UNIQUE included a 2D-2D matching capability and tests were performed to identify system repositioning capability. Finally, since the system is capable of delivering volumetric modulated arc therapy with RapidArc, a summary of the tests performed for such modality to assess its performance in preclinical settings and during clinical usage was included. Isocenter virtual diameter was measured as less than 0.2 mm. Observed accuracy of isocenter determination and repositioning for 2D-2D matching procedures in image guidance was 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.

  5. Experimental Platform for Ultra-high Dose Rate FLASH Irradiation of Small Animals Using a Clinical Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Schüler, Emil; Trovati, Stefania; King, Gregory; Lartey, Frederick; Rafat, Marjan; Villegas, Manuel; Praxel, A. Joe [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Loo, Billy W., E-mail: BWLoo@stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California (United States); Maxim, Peter G., E-mail: PMaxim@stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California (United States)

    2017-01-01

    Purpose: A key factor limiting the effectiveness of radiation therapy is normal tissue toxicity, and recent preclinical data have shown that ultra-high dose rate irradiation (>50 Gy/s, “FLASH”) potentially mitigates this effect. However, research in this field has been strongly limited by the availability of FLASH irradiators suitable for small animal experiments. We present a simple methodologic approach for FLASH electron small animal irradiation with a clinically available linear accelerator (LINAC). Methods and Materials: We investigated the FLASH irradiation potential of a Varian Clinac 21EX in both clinical mode and after tuning of the LINAC. We performed detailed FLUKA Monte Carlo and experimental dosimetric characterization at multiple experimental locations within the LINAC head. Results: Average dose rates of ≤74 Gy/s were achieved in clinical mode, and the dose rate after tuning exceeded 900 Gy/s. We obtained 220 Gy/s at 1-cm depth for a >4-cm field size with 90% homogeneity throughout a 2-cm-thick volume. Conclusions: We present an approach for using a clinical LINAC for FLASH irradiation. We obtained dose rates exceeding 200 Gy/s after simple tuning of the LINAC, with excellent dosimetric properties for small animal experiments. This will allow for increased availability of FLASH irradiation to the general research community.

  6. New concept on an integrated interior magnetic resonance imaging and medical linear accelerator system for radiation therapy.

    Science.gov (United States)

    Jia, Xun; Tian, Zhen; Xi, Yan; Jiang, Steve B; Wang, Ge

    2017-01-01

    Image guidance plays a critical role in radiotherapy. Currently, cone-beam computed tomography (CBCT) is routinely used in clinics for this purpose. While this modality can provide an attenuation image for therapeutic planning, low soft-tissue contrast affects the delineation of anatomical and pathological features. Efforts have recently been devoted to several MRI linear accelerator (LINAC) projects that lead to the successful combination of a full diagnostic MRI scanner with a radiotherapy machine. We present a new concept for the development of the MRI-LINAC system. Instead of combining a full MRI scanner with the LINAC platform, we propose using an interior MRI (iMRI) approach to image a specific region of interest (RoI) containing the radiation treatment target. While the conventional CBCT component still delivers a global image of the patient's anatomy, the iMRI offers local imaging of high soft-tissue contrast for tumor delineation. We describe a top-level system design for the integration of an iMRI component into an existing LINAC platform. We performed numerical analyses of the magnetic field for the iMRI to show potentially acceptable field properties in a spherical RoI with a diameter of 15 cm. This field could be shielded to a sufficiently low level around the LINAC region to avoid electromagnetic interference. Furthermore, we investigate the dosimetric impacts of this integration on the radiotherapy beam.

  7. 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.

  8. Calibration of an Electron Linear Accelerator using an acrylic puppet; Calibracion de un Acelerador Lineal de Electrones usando maniqui de acrilico

    Energy Technology Data Exchange (ETDEWEB)

    Guzman C, C.S.; Picon C, C. [Instituto de Enfermedades Neoplasicas, Departamento de Radioterapia-Servicio de Fisica, Av. Angamos 2520, Lima 34 (Peru)

    1998-12-31

    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)

  9. Medium-Term Stability of the Photon Beam Energy of An Elekta CompactTM Linear Accelerator Based on Daily Measurements of Beam Quality Factor

    Directory of Open Access Journals (Sweden)

    Mohammad Amin Mosleh-Shirazi

    2016-04-01

    Full Text Available Introduction In this study, we aimed to assess the medium-term energy stability of a 6MV Elekta CompactTM linear accelerator. To the best of our knowledge, this is the first published article to evaluate this linear accelerator in terms of energy stability. As well as investigating the stability of the linear accelerator energy over a period of several weeks, the results will be useful for estimation of the required tolerance values for the beam quality factor (BQF of the PTW QUICKCHECK weblineTM (QCW daily checking device. Materials and Methods Over a 13 week period of routine clinical service, 52 daily readings of BQF were taken and then analyzed for a 10×10 cm2 field. Results No decreasing or increasing trend in BQF was observed over the study period. The mean BQF value was estimated at 5.4483 with a standard deviation (SD of 0.0459 (0.8%. The mean value was only 0.1% different from the baseline value. Conclusion The results of this medium-term stability study of the Elekta Compact linear accelerator energy showed that 96.2% of the observed BQF values were within ±1.3% of the baseline value. This can be considered to be within the recommended tolerance for linear accelerator photon beam energy. If an approach of applying ±3 SD is taken, the tolerance level for BQF may be suggested to be set at ±2.5%. However, further research is required to establish a relationship between BQF value and the actual changes in beam energy and penetrative quality.

  10. Treatment of Cerebral Arteriovenous Malformations with Radiosurgery or Hypofractionated Stereotactic Radiotherapy in a Consecutive Pooled Linear Accelerator Series.

    Science.gov (United States)

    Boström, Jan P; Bruckermann, Ruth; Pintea, Bogdan; Boström, Azize; Surber, Gunnar; Hamm, Klaus

    2016-10-01

    To review outcomes after linear accelerator stereotactic radiosurgery (SRS) and hypofractionated stereotactic radiotherapy (hfSRT) of arteriovenous malformations (AVMs) from a consecutive and pooled series of 2 Novalis centers and to analyze the influence of AVM size, Spetzler-Martin (SM) grade, pretreatment, and hemorrhagic versus nonhemorrhagic presentation. A subgroup analysis of A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA)-eligible patients also was performed. Prospectively collected treatment and outcome data were supplemented by retrospectively collected follow-up data for 93.8% of all patients. A total of 129 patients with AVM had SRS or hfSRT between 2000 and 2014 with the same linear accelerator system in 2 centers. Data analysis included initial presentation, SM grade, occlusion rates assessed by magnetic resonance and/or digital subtraction angiography, neurologic and therapeutic complications, and pretreatments. Statistical analysis was performed for patient demographic data and for factors potentially influencing outcome. Initial presentation was hemorrhage in 43.8% or seizures/neurologic deficits in 46.2%. The series included 6 SM grade I (5%), 26 SM II (21.5%), 55 SM III (45.5%), 28 SM IV (23%), and 6 SM V cases (5%). Pre-embolization was used in 36 patients (29.8%), 8 patients had previous surgery (6.6%), and 6 patients were irradiated before elsewhere (5%); 5 patients (4.2%) received multimodal pretreatment. Mean follow-up was 43 months. The occlusion rate for the total series was 71.1%, for SM I/II cases 80.6%, and 67.4% for the SM ≥ subgroup. The occlusion rate was 75.0% for the small volume (10 cc) subgroup. There was no statistical difference between the occlusion rate of patients with or without pretreatment if taken all modalities together (72.7% and 69.7%, respectively). There was only a trend of a belated occlusion of pre-embolized AVMs. The occlusion rate for hemorrhagic AVM was with 77.4% better than for

  11. Children of low socioeconomic status show accelerated linear growth in early childhood; results from the Generation R Study.

    Directory of Open Access Journals (Sweden)

    Lindsay M Silva

    Full Text Available OBJECTIVES: People of low socioeconomic status are shorter than those of high socioeconomic status. The first two years of life being critical for height development, we hypothesized that a low socioeconomic status is associated with a slower linear growth in early childhood. We studied maternal educational level (high, mid-high, mid-low, and low as a measure of socioeconomic status and its association with repeatedly measured height in children aged 0-2 years, and also examined to what extent known determinants of postnatal growth contribute to this association. METHODS: This study was based on data from 2972 mothers with a Dutch ethnicity, and their children participating in The Generation R Study, a population-based cohort study in Rotterdam, The Netherlands (participation rate 61%. All children were born between April 2002 and January 2006. Height was measured at 2 months (mid-90% range 1.0-3.9, 6 months (mid-90% range 5.6-11.4, 14 months (mid-90% range 13.7-17.9 and 25 months of age (mid-90% range 23.6-29.6. RESULTS: At 2 months, children in the lowest educational subgroup were shorter than those in the highest (difference: -0.87 cm; 95% CI: -1.16, -0.58. Between 1 and 18 months, they grew faster than their counterparts. By 14 months, children in the lowest educational subgroup were taller than those in the highest (difference at 14 months: 0.40 cm; 95% CI: 0.08,0.72. Adjustment for other determinants of postnatal growth did not explain the taller height. On the contrary, the differences became even larger (difference at 14 months: 0.61 cm; 95% CI: 0.26,0.95; and at 25 months: 1.00 cm; 95% CI: 0.57,1.43 CONCLUSIONS: Compared with children of high socioeconomic status, those of low socioeconomic status show an accelerated linear growth until the 18th month of life, leading to an overcompensation of their initial height deficit. The long-term consequences of these findings remain unclear and require further study.

  12. SU-E-T-354: Efficient and Enhanced QA Testing of Linear Accelerators Using a Real-Time Beam Monitor

    Energy Technology Data Exchange (ETDEWEB)

    Jung, J; Farrokhkish, M; Norrlinger, B; Wang, Y [Princess Margaret Cancer Centre, Toronto, Ontario (Canada); Heaton, R; Jaffray, D; Islam, M [Princess Margaret Cancer Centre, Toronto, Ontario (Canada); University of Toronto, Toronto, Ontario (Canada)

    2015-06-15

    Purpose: To investigate the feasibility of performing routine QA tests of linear accelerators (Linac) using the Integral Quality Monitoring (IQM) system. The system, consisting of a 1-D sensitivity gradient large area ion-chamber mounted at the collimator, allows automatic collection and analysis of beam data. Methods: The IQM was investigated to perform several QA constancy tests, similar to those recommended by AAPM TG142, of a Linac including: beam output, MLC calibration, beam symmetry, relative dose factor (RDF), dose linearity, output as a function of gantry angle and dose rate. All measurements by the IQM system accompanied a reference measurement using a conventional dosimetry system and were performed on an Elekta Infinity Linac with Agility MLC. The MLC calibration check is done using a Picket-Fence type 2×10cm{sup 2} field positioned at different off-axis locations along the chamber gradient. Beam symmetry constancy values are established by signals from an 4×4cm{sup 2} aperture located at various off-axis positions; the sensitivity of the test was determined by the changes in the signals in response to a tilt in the beam. The data for various square field sizes were used to develop a functional relationship with RDF. Results: The IQM tracked the beam output well within 1% of the reference ion-chamber readings. The Picket-Fence type field test detected a 1mm shift error of one MLC bank. The system was able to detect 2.5% or greater beam asymmetry. The IQM results for all other QA tests were found to agree with the reference values to within 0.5%. Conclusion: It was demonstrated that the IQM system can effectively monitor the Linac performance parameters for the purpose of routine QA constancy tests. With minimum user interactions a comprehensive set of tests can be performed efficiently, allowing frequent monitoring of the Linac. The presenting author’s salary is funded by the manufacturer of the QA device. All the other authors have financial

  13. 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.

  14. SU-F-T-467: A Cross-Checking Approach for Dosimetric Verification of Beam- Matched Elekta Linear Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Y; Yuan, J; Geis, P; Colussi, V; Machtay, M; Ellis, R; Wessels, B [University Hospitals Case Medical Center, Dept of Radiation Oncology, Cleveland, OH (United States)

    2016-06-15

    Purpose: To verify the similarity of the dosimetric characteristics between two Elekta linear accelerators (linacs) in order to treat patients interchangeably on these two machines without re-planning. Methods: To investigate the viability of matching the 6 MV flattened beam on an existing linac (Elekta Synergy with Agility head) with a recently installed new linca (Elekta Versa HD), percent depth doses (PDD), flatness and symmetry output factors were compared for both machines. To validate the beam matching among machines, we carried out two approaches to cross-check the dosimetrical equivalence: 1) the prior treatment plans were re-computed based on the newly built Versa HD treatment planning system (TPS) model without changing the beam control points; 2) The same plans were delivered on both machines and the radiation dose measurements on a MapCheck2 were compared with TPS calculations. Three VMAT plans (Head and neck, lung, and prostate) were used in the study. Results: The difference between the PDDs for 10×10 cm{sup 2} field at all depths was less than 0.8%. The difference of flatness and symmetry for 30×30 cm{sup 2} field was less than 0.8%, and the measured output factors varies by less than 1% for each field size ranging from 2×2 cm2 to 40×40 cm{sup 2}. For the same plans, the maximum difference of the two calculated dose distributions is 2% of prescription. For the QA measurements, the gamma index passing rates were above 99% for 3%/3mm criteria with 10% threshold for all three clinical plans. Conclusion: A beam modality matching between two Elekta linacs is demonstrated with a cross-checking approach.

  15. Linear accelerator-based stereotactic radiosurgery of intracranial meningiomas: results of the first 5 years of clinical practice.

    Science.gov (United States)

    Abdelaziz, Osama S; Kandil, Alaa; El-Assaal, Shaaban; Abdelaziz, Amro; Rostom, Yosry; Rashed, Yaser

    2011-01-01

    Meningiomas are mostly benign but some are atypical or malignant. Surgical resection is curative when complete removal of benign meningiomas is contemplated. Incompletely excised and recurrent tumors are frequently treated with fractionated radiation therapy or stereotactic radiosurgery. The purpose of this study is to evaluate the short-term radiological and functional outcomes of a single center using linear accelerator (Linac) stereotactic radiosurgery for the treatment of intracranial meningiomas. Twenty-nine patients (12 males and 17 females) with 30 meningiomas, in different brain locations (skull base and non-skull base meningiomas), were treated with Linac-based stereotactic radiosurgery. The mean tumor volume was 6.3 cm³, and the mean tumor marginal and maximum doses were 10.9 and 15 Gy, respectively. The median prescribed isodose line was 80%. The patients were followed-up for a minimum of 3 years. Regarding radiological outcome, nine (30%) meningiomas demonstrated evident volume reduction, 19 (63.3%) meningiomas remained unchanged, and two (6.7%) meningiomas increased in size after radiosurgery. The local tumor control rates for skull base meningiomas and non-skull base meningiomas after radiosurgery were 90.9% and 100%, respectively. Regarding functional outcomes, 64% of patients presenting with cranial neuropathies showed improvement of their cranial nerve functions and 29% of patients remained unchanged. One patient had temporary trigeminal neuropathy. Although radiosurgery for meningiomas is generally effective and quite safe in achieving high control rates with minimum morbidity over short- and intermediate-term periods of follow-up, tumor progression might occur in a delayed manner after initial apparent control for few years. We recommend continued follow-up for longer periods to better assess the long-term outcomes.

  16. Development and characterization of an interferometer for calorimeter-based absorbed dose to water measurements in a medical linear accelerator

    Science.gov (United States)

    Flores-Martinez, Everardo; Malin, Martha J.; DeWerd, Larry A.

    2016-11-01

    The quantity of relevance for external beam radiotherapy is absorbed dose to water (ADW). An interferometer was built, characterized, and tested to measure ADW within the dose range of interest for external beam radiotherapy using the temperature dependence of the refractive index of water. The interferometer was used to measure radiation-induced phase shifts of a laser beam passing through a (10 × 10 × 10) cm3 water-filled glass phantom, irradiated with a 6 MV photon beam from a medical linear accelerator. The field size was (7 × 7) cm2 and the dose was measured at a depth of 5 cm in the water phantom. The intensity of the interference pattern was measured with a photodiode and was used to calculate the time-dependent phase shift curve. The system was thermally insulated to achieve temperature drifts of less than 1.5 mK/min. Data were acquired 60 s before and after the irradiation. The radiation-induced phase shifts were calculated by taking the difference in the pre- and post-irradiation drifts extrapolated to the midpoint of the irradiation. For 200, 300, and 400 monitor units, the measured doses were 1.6 ± 0.3, 2.6 ± 0.3, and 3.1 ± 0.3 Gy, respectively. Measurements agreed within the uncertainty with dose calculations performed with a treatment planning system. The estimated type-A, k = 1 uncertainty in the measured doses was 0.3 Gy which is an order of magnitude lower than previously published interferometer-based ADW measurements.

  17. Rotational IMRT delivery using a digital linear accelerator in very high dose rate 'burst mode'

    Energy Technology Data Exchange (ETDEWEB)

    Salter, Bill J; Sarkar, Vikren; Wang, Brian; Szegedi, Martin; Rassiah-Szegedi, Prema [Department of Radiation Oncology, University of Utah, Salt Lake City, UT (United States); Shukla, Himanshu, E-mail: bill.salter@hci.utah.edu [Oncology Care Systems Group, Siemens Medical Solutions (USA), 4040 Nelson Avenue, Concord, CA (United States)

    2011-04-07

    Recently, there has been a resurgence of interest in arc-based IMRT, through the use of 'conventional' multileaf collimator (MLC) systems that can treat large tumor volumes in a single, or very few pass(es) of the gantry. Here we present a novel 'burst mode' modulated arc delivery approach, wherein 2000 monitor units per minute (MU min{sup -1}) high dose rate bursts of dose are facilitated by a flattening-filter-free treatment beam on a Siemens Artiste (Oncology Care Systems, Siemens Medical Solutions, Concord, CA, USA) digital linear accelerator in a non-clinical configuration. Burst mode delivery differs from continuous mode delivery, used by Elekta's VMAT (Elekta Ltd, Crawley, UK) and Varian's RapidArc (Varian Medical Systems, Palo Alto, CA, USA) implementations, in that dose is not delivered while MLC leaves are moving. Instead, dose is delivered in bursts over very short arc angles and only after an MLC segment shape has been completely formed and verified by the controller. The new system was confirmed to be capable of delivering a wide array of clinically relevant treatment plans, without machine fault or other delivery anomalies. Dosimetric accuracy of the modulated arc platform, as well as the Prowess (Prowess Inc., Concord, CA, USA) prototype treatment planning version utilized here, was quantified and confirmed, and delivery times were measured as significantly brief, even with large hypofractionated doses. The burst mode modulated arc approach evaluated here appears to represent a capable, accurate and efficient delivery approach.

  18. SU-E-T-194: Commissioning of Monaco Treatment Planning System On An Elekta VersaHD Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Narayanasamy, G; Bosse, C; Saenz, D; Cruz, W; Papanikolaou, N; Stathakis, S [University of Texas Health Science Center at San Antonio, TX (United States); Mavroidis, P [University of North Carolina, Chapel Hill, NC (United States)

    2015-06-15

    Purpose: The Monaco treatment planning system (TPS) uses a Monte-Carlo algorithm based dose computation engine to model the photon beams of a linear accelerator. The aim is to perform verification of Monaco TPS beam modeling of a Elekta VersaHD linac with 6MV, 6MV FFF, 10 MV, 10MV FFF, 18MV photon beams and 160 multileaf collimators (MLC) with a projected width of 5-mm at the isocenter. Methods: A series of dosimetric tests were performed to validate Monaco calculated beams including point dose measurement in water with and without heterogeneity and 2-dimensional dose distributions on a Delta4 bi-planar diode dosimeter array (Scandidos, Uppsala, Sweden). 3D conformal beams of different field sizes, source-to-surface distances, wedges, and gantry angles were delivered onto a phantom consisting of several plastic water and Styrofoam slabs. Point dose measurements were verified with a PTW 31013 Semiflex 0.3 cc ionization chamber (PTW, Freiburg, Germany). In addition, 8 step and shoot intensity modulated radiotherapy (IMRT) and volumetric modulated arc radiotherapy (VMAT) beams included in the Monaco TPS commissioning suite were verified against measurements on Delta4 to test and fine tune parameters in the beam model. IMRT verification was computed using gamma analysis with dose difference and distance-to-agreement criteria of 3%/3mm with a dose threshold of 10%. Results: Point dose measurements agreed within 2% in the homogeneous phantom and within 3% in the heterogeneous phantom for all photon energies. IMRT beams yielded a passing percentage of 99.1±1.1% in the gamma analysis which is well above the institutional passing threshold of 90%. Conclusion: Monaco TPS commissioning was successfully performed for all the photon energies on the Elekta VersaHD linac prior to clinical usage.

  19. Developmental maturation of ionotropic glutamate receptor subunits in rat vestibular nuclear neurons responsive to vertical linear acceleration.

    Science.gov (United States)

    Lai, Suk-King; Lai, Chun-Hong; Tse, Yiu-Chung; Yung, Ken K L; Shum, Daisy K Y; Chan, Ying-Shing

    2008-12-01

    We investigated the maturation profile of subunits of ionotropic glutamate receptors in vestibular nuclear neurons that were activated by sinusoidal linear acceleration along the vertical plane. The otolithic origin of Fos expression in these neurons was confirmed as a marker of functional activation when labyrinthectomized and/or stationary control rats contrasted by showing sporadically scattered Fos-labeled neurons in the vestibular nuclei. By double immunohistochemistry for Fos and one of the receptor subunits, otolith-related neurons that expressed either alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate or N-methyl-d-aspartate subunits were first identified in the medial vestibular nucleus, spinal vestibular nucleus and Group x by postnatal day (P)7, and in the lateral vestibular nucleus and Group y by P9. No double-labeled neurons were found in the superior vestibular nucleus. Within each vestibular subnucleus, these double-labeled neurons constituted approximately 90% of the total Fos-labeled neurons. The percentage of Fos-labeled neurons expressing the GluR1 or NR2A subunit showed developmental invariance in all subnuclei. For Fos-labeled neurons expressing the NR1 subunit, similar invariance was observed except that, in Group y, these neurons decreased from P14 onwards. For Fos-labeled neurons expressing the GluR2, GluR2/3, GluR4 or NR2B subunit, a significant decrease was found by the adult stage. In particular, those expressing the GluR4 subunit showed a two- to threefold decrease in the medial vestibular nucleus, spinal vestibular nucleus and Group y. Also, those expressing the NR2B subunit showed a twofold decrease in Group y. Taken together, the postsynaptic expression of ionotropic glutamate receptor subunits in different vestibular subnuclei suggests that glutamatergic transmission within subregions plays differential developmental roles in the coding of gravity-related vertical spatial information.

  20. 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

  1. 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.

    Science.gov (United States)

    Sarkar, B; Pradhan, A; Munshi, A

    2016-01-01

    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. 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. 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. The dosimetry of VMAT-based SRS/SRT treatment plan had minimal dependence on MLC and beam model variations. All tested MLC and beam model could fulfil the desired PTV coverage and organs at risk

  2. 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)

  3. Off-center yaw rotation: effect of naso-occipital linear acceleration on the nystagmus response of normal human subjects and patients after unilateral vestibular loss.

    Science.gov (United States)

    Curthoys, I S; Haslwanter, T; Black, R A; Burgess, A M; Halmagyi, G M; Topple, A N; Todd, M J

    1998-12-01

    Dual search coils were used to record horizontal, vertical and torsional eye movement components of one eye during nystagmus caused by off-center yaw rotation (yaw centrifugation). Both normal healthy human subjects (n=7) and patients with only one functioning labyrinth (n=12) were studied in order to clarify how the concomitant linear acceleration affected the nystagmus response. Each subject was seated with head erect on the arm of a fixed-chair human centrifuge, 1 m away from the center of the rotation, and positioned to be facing along a radius; either towards (facing-in) or away from (facing-out) the center of rotation. Both yaw right and yaw left angular accelerations of 10 degrees s(-2) from 0 to 200 degrees/s were studied. During rotation a centripetal linear acceleration (increasing from 0 to 1.24xg units) was directed along the subject's naso-occipital axis resulting in a shift of the resultant angle of the gravitoinertial acceleration (GIA) of 51 degrees in the subject's pitch plane and an increase in the total GIA magnitude from 1.0 to 1.59xg. In normal subjects during the angular acceleration off-center there were, in addition to the horizontal eye velocity components, torsional and vertical eye velocities present. The magnitude of these additional components, although small, was larger than observed during similar experiments with on-center angular acceleration (Haslwanter et al. 1996), and the change in these components is attributed to the additional effect of the linear acceleration stimulation. In the pitch plane the average size of the shift of the axis of eye velocity (AEV) during the acceleration was about 8 degrees for a 51 degrees shift of the GIA (around 16% of the GIA shift) so that the AEV-GIA alignment was inadequate. There was a very marked difference in the size of the AEV shift depending on whether the person was facing-in [AEV shift forward (i.e. non-compensatory) of about 4 degrees] or facing-out [AEV shift forward (i.e. compensatory

  4. Accelerating health equity: the key role of universal health coverage in the Sustainable Development Goals.

    Science.gov (United States)

    Tangcharoensathien, Viroj; Mills, Anne; Palu, Toomas

    2015-04-29

    The Sustainable Development Goals (SDGs), to be committed to by Heads of State at the upcoming 2015 United Nations General Assembly, have set much higher and more ambitious health-related goals and targets than did the Millennium Development Goals (MDGs). The main challenge among MDG off-track countries is the failure to provide and sustain financial access to quality services by communities, especially the poor. Universal health coverage (UHC), one of the SDG health targets indispensable to achieving an improved level and distribution of health, requires a significant increase in government investment in strengthening primary healthcare - the close-to-client service which can result in equitable access. Given the trend of increased fiscal capacity in most developing countries, aiming at long-term progress toward UHC is feasible, if there is political commitment and if focused, effective policies are in place. Trends in high income countries, including an aging population which increases demand for health workers, continue to trigger international migration of health personnel from low and middle income countries. The inspirational SDGs must be matched with redoubled government efforts to strengthen health delivery systems, produce and retain more and relevant health workers, and progressively realize UHC.

  5. Improvement in clinical step and shoot intensity modulated radiation therapy delivery accuracy on an integrated linear accelerator control system.

    Science.gov (United States)

    Agnew, C E; Irvine, D M; Hounsell, A R; McGarry, C K

    2014-01-01

    The dose delivery accuracy of 30 clinical step and shoot intensity modulated radiation therapy plans was investigated using the single integrated multileaf collimator controller of the Varian Truebeam linear accelerator (linac) (Varian Medical Systems, Palo Alto, CA) and compared with the dose delivery accuracy on a previous generation Varian 2100CD C-Series linac. Ten prostate, 10 prostate and pelvic node, and 10 head-and-neck cases were investigated in this study. Dose delivery accuracy on each linac was assessed using Farmer ionization chamber point dose measurements, 2-dimensional planar ionization chamber array measurements, and the corresponding Varian dynamic log files. Absolute point dose measurements, fluence delivery accuracy, leaf position accuracy, and the overshoot effect were assessed for each plan. Absolute point dose delivery accuracy increased by 1.5% on the Truebeam compared with the 2100CD linac. No improvement in fluence delivery accuracy between the linacs, at a gamma criterion of 3%/3 mm was measured using the 2-dimensional ionization chamber array, with median (interquartile range) gamma passing rates of 98.99% (97.70%-99.72%) and 99.28% (98.26%-99.75%) for the Truebeam and 2100CD linacs, respectively. Varian log files also showed no improvement in fluence delivery between the linacs at 3%/3 mm, with median gamma passing rates of 99.97% (99.93%-99.99%) and 99.98% (99.94%-100%) for the Truebeam and 2100CD linacs, respectively. However, log files revealed improved leaf position accuracy and fluence delivery at 1%/1 mm criterion on the Truebeam (99.87%; 99.78%-99.94%) compared with the 2100CD linac (97.87%; 91.93%-99.49%). The overshoot effect, characterized on the 2100CD linac, was not observed on the Truebeam. The integrated multileaf collimator controller on the Varian Truebeam improves clinical treatment delivery accuracy of step and shoot intensity modulated radiation therapy fields compared with delivery on a Varian C-series linac. Crown

  6. Analysis of physical parameters and determination of inflection point for Flattening Filter Free beams in medical linear accelerator.

    Science.gov (United States)

    Pichandi, A; Ganesh, Kadirampatti Mani; Jerin, Amalraj; Balaji, Karunakaran; Kilara, Gurunath

    2014-09-01

    Medical Linear accelerators manufactured without flattening filters are increasing popular in recent days. The removal of flattening filter results in increased dose rate, reduced mean energy, reduction in head leakage and lateral scattering, which have shown advantageous when used for special treatment procedures. This study aims to analyze physical parameters of FFF beams and to determine the inflection point for standardizing the beam flatness and penumbra. The beam profiles and depth dose patterns were measured using Radiation Field Analyzer (RFA) with 0.13 cc cylindrical ion chamber. The beam energy characteristics, head scatter factor (Sc) were obtained for 6FFF and 10FFF beams and compared with 6 MV and 10 MV photons, respectively. The symmetry and stability of unflattened regions were also analyzed. In addition, the study proposes a simple physical concept for obtaining inflection point for FFF beams and results were compared using the Akima spline interpolation method. The inflection point was used to determine the field size and penumbra of FFF beams. The Sc varied from 0.922 to 1.044 for 6FFF and from 0.913 to 1.044 for 10FFF with field sizes from 3 cm × 3 cm to 40 cm × 40 cm which is much less than FF beams. The obtained value of field size and penumbra for both simple physical concept and Akima spline interpolation methods is within the ±1.0 mm for the field size and ±2 mm penumbra. The results indicate that FFF beams reduce Sc compared with FF beams due to the absence of a flattening filter. The proposed simple method to find field size and penumbra using inflection point can be accepted as it is closely approximated to mathematical results. Stability of these parameters was ascertained by repeated measurements and the study indicates good stability for FFF beam similar to that of FF beams.

  7. Thermal limits on MV x-ray production by bremsstrahlung targets in the context of novel linear accelerators.

    Science.gov (United States)

    Wang, Jinghui; Trovati, Stefania; Borchard, Philipp M; Loo, Billy W; Maxim, Peter G; Fahrig, Rebecca

    2017-12-01

    To study the impact of target geometrical and linac operational parameters, such as target material and thickness, electron beam size, repetition rate, and mean current on the ability of the radiotherapy treatment head to deliver high-dose-rate x-ray irradiation in the context of novel linear accelerators capable of higher repetition rates/duty cycle than conventional clinical linacs. The depth dose in a water phantom without a flattening filter and heat deposition in an x-ray target by 10 MeV pulsed electron beams were calculated using the Monte-Carlo code MCNPX, and the transient temperature behavior of the target was simulated by ANSYS. Several parameters that affect both the dose distribution and temperature behavior were investigated. The target was tungsten with a thickness ranging from 0 to 3 mm and a copper heat remover layer. An electron beam with full width at half maximum (FWHM) between 0 and3 mm and mean current of 0.05-2 mA was used as the primary beam at repetition rates of 100, 200, 400, and 800 Hz. For a 10 MeV electron beam with FWHM of 1 mm, pulse length of 5 μs, by using a thin tungsten target with thickness of 0.2 mm instead of 1 mm, and by employing a high repetition rate of 800 Hz instead of 100 Hz, the maximum dose rate delivered can increase two times from 0.57 to 1.16 Gy/s. In this simple model, the limiting factor on dose rate is the copper heat remover's softening temperature, which was considered to be 500°C in our study. A high dose rate can be obtained by employing thin targets together with high repetition rate electron beams enabled by novel linac designs, whereas the benefit of thin targets is marginal at conventional repetition rates. Next generation linacs used to increase dose rate need different target designs compared to conventional linacs. © 2017 American Association of Physicists in Medicine.

  8. Targeting Accuracy of Image-Guided Radiosurgery for Intracranial Lesions: A Comparison Across Multiple Linear Accelerator Platforms.

    Science.gov (United States)

    Huang, Yimei; Zhao, Bo; Chetty, Indrin J; Brown, Stephen; Gordon, James; Wen, Ning

    2016-04-01

    To evaluate the overall positioning accuracy of image-guided intracranial radiosurgery across multiple linear accelerator platforms. A computed tomography scan with a slice thickness of 1.0 mm was acquired of an anthropomorphic head phantom in a BrainLAB U-frame mask. The phantom was embedded with three 5-mm diameter tungsten ball bearings, simulating a central, a left, and an anterior cranial lesion. The ball bearings were positioned to radiation isocenter under ExacTrac X-ray or cone-beam computed tomography image guidance on 3 Linacs: (1) ExacTrac X-ray localization on a Novalis Tx; (2) cone-beam computed tomography localization on the Novalis Tx; (3) cone-beam computed tomography localization on a TrueBeam; and (4) cone-beam computed tomography localization on an Edge. Each ball bearing was positioned 5 times to the radiation isocenter with different initial setup error following the 4 image guidance procedures on the 3 Linacs, and the mean (µ) and one standard deviation (σ) of the residual error were compared. Averaged overall 3 ball bearing locations, the vector length of the residual setup error in mm (µ ± σ) was 0.6 ± 0.2, 1.0 ± 0.5, 0.2 ± 0.1, and 0.3 ± 0.1 on ExacTrac X-ray localization on a Novalis Tx, cone-beam computed tomography localization on the Novalis Tx, cone-beam computed tomography localization on a TrueBeam, and cone-beam computed tomography localization on an Edge, with their range in mm being 0.4 to 1.1, 0.4 to 1.9, 0.1 to 0.5, and 0.2 to 0.6, respectively. The congruence between imaging and radiation isocenters in mm was 0.6 ± 0.1, 0.7 ± 0.1, 0.3 ± 0.1, and 0.2 ± 0.1, for the 4 systems, respectively. Targeting accuracy comparable to frame-based stereotactic radiosurgery can be achieved with image-guided intracranial stereotactic radiosurgery treatment. © The Author(s) 2015.

  9. 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

  10. 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)

  11. Poster - Thur Eve - 50: Planning and delivery accuracy of stereotactic radiosurgery with Tomotherapy as compared to linear-accelerator and robotic based radiosurgery.

    Science.gov (United States)

    Thakur, V; Soisson, E; Ruo, R; Doucet, R; Parker, W; Seuntjens, J

    2012-07-01

    This study includes planning and delivery comparison of three stereotactic radiosurgery techniques : Helical Tomotherapy (HT), circular collimator-based Linear-accelerator and robotic-radiosurgery. Plans were generated for two spherical targets of diameter 6 mm and 10 mm contoured at the center of a Lucite phantom, using similar planning constrains. Planning comparison showed that average conformality (0-1best) for Linear-accelerator, robotic-radiosurgery and HT was 1.43, 1.24, and 1.77 and gradient index (less is better) was 2.72, 4.50 and 13.56 respectively. For delivery comparison, plans were delivered to radiochromic film and measured dose was compared with the planned dose. For Linear-accelerator and robotic-radiosurgery more than 99% pixels-passing a gamma criteria of 3% dose difference and 1 mm distance to agreement where as for HT this value was as low as 40% for off-axis targets. Further investigation of the delivery accuracy as a function of the location of the target with in the bore was initiated using small volume A1SL (0.057 cm3 ) and MicroLion liquid ion chamber (0.0017 cm3 ). Point dose measurements for targets located at the center and 10 cm away from the center of the bore showed that delivered dose varied by more than 15% for targets placed away from the center of the bore as opposed to at the center. In conclusion, Linear-accelerator and the robotic-radiosurgery techniques showed preferable gradient and conformality. For HT, point dose measurements were significantly lower than predicted by the TPS when the target was positioned away from the isocenter, while they were found to be higher at isocenter. © 2012 American Association of Physicists in Medicine.

  12. Implementation of a linear mini accelerator for radiotherapy intraoperative; Puesta en marcha de un miniacelerador lineal para radioterapia intraoperatoria

    Energy Technology Data Exchange (ETDEWEB)

    Macias-Verde, D.; Yanez-Lopez, D.; Marti-Asenjo, J.; Sanchez-Carrascal, M.; Torres-Pozas, S.; Godoy-Cazorla, J. I.; Madan-Rodriguez, C.; Martin-Oliva, R.

    2013-07-01

    Has been defined the status initial reference of the lineal mini-accelerator Intrabeam PRS 500. The alternative worksheet in times of treatment provides an additional verification. The system is validated for clinical use. (Author)

  13. Validation of Monte Carlo simulation of 6 MV photon beam produced by Varian Clinac 2100 linear accelerator using BEAMnrc code and DOSXYZnrc code

    Science.gov (United States)

    Bencheikh, Mohamed; Maghnouj, Abdelmajid; Tajmouati, Jaouad; Didi, Abdessamad; Ezzati, Ahad Olah

    2017-09-01

    The Monte Carlo model for the photon-beam output from the Varian Clinac 2100 linear accelerator was validated to compare the calculated to measured PDD and beam dose profiles The Monte Carlo calculation method is considered to be the most accurate method for dose calculation in radiotherapy. The objective of this study is to build a Monte Carlo geometry of Varian Clinac 2100 linear accelerator as realistically as possible. The Monte Carlo codes used in this work were the BEAMnrc code to simulate the photons beam and the DOSXYZnrc code to examinate the absorbed dose in the water phantom. We have calculated percentage depth dose (PDD) and beam profiles of the 6 MV photon beam for the 6 × 6 cm2, 10 × 10 cm2 and 15 × 15 cm2 field sizes. We have used the gamma index technique for the quantitative evaluation to compare the measured and calculated distributions. Good agreement was found between calculated PDD and beam profile compared to measured data. The comparison was evaluated using the gamma index method and the criterions were 3% for dose difference and 3 mm for distance to agreement. The gamma index acceptance rate was more than 97% of both distribution comparisons PDDs and dose profiles and our results were more developed and accurate. The Varian Clinac 2100 linear accelerator was accurately modeled using Monte Carlo codes: BEAMnrc and DOSXYZnrc codes package.

  14. Accelerated Urban Expansion in Lhasa City and the Implications for Sustainable Development in a Plateau City

    Directory of Open Access Journals (Sweden)

    Wei Tang

    2017-08-01

    Full Text Available Urbanization challenges regional sustainable development, but a slight expansion mechanism was revealed in a plateau city. We have integrated the urban expansion process and analyzed its determinants in Lhasa (Tibet, and we provide insightful suggestions for urban management and planning for Lhasa. The full continuum of the urban expansion process has been captured using time-series of high-resolution remote sensing data (1990–2015. Four categories of potential determinants involved in economic, demographic, social, and government policy factors were selected, and redundancy analysis was employed to define the contribution rates of these determinants. The results illustrate that considerable urban expansion occurred from 1990 to 2015 in Lhasa, with the area of construction land and transportation land increasing at rates of 117.2% and 564.7%, respectively. The urban expansion in the center of Lhasa can be characterized as temperate sprawl from 1990 through 2008, primarily explained by governmental policies and investment, economic development, tourist growth, and increased governmental investment resulting in faster urban expansion from 2008 to 2015, mainly occurring in the east, south, and west of Lhasa. In contrast with other cities of China, central government investment and “pairing-up support” projects have played an important role in infrastructure construction in Lhasa. The miraculous development of the tourism industry had prominent effects on this economic development and urbanization after 2006, due to the running of the Tibetan Railway. An integrative and proactive policy framework, the “Lhasa development model”, having important theoretical, methodological, and management implications for urban planning and development, has been proposed.

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

    Science.gov (United States)

    Li, Ji; Wiersma, Rodney D; Stepaniak, Christopher J; Farrey, Karl J; Al-Hallaq, Hania A

    2012-05-01

    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. An SMLC sequence was created consisting of ten identical 10 × 10 cm(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(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 (Δ(i)) were compared using F-tests (α = 0.05). On the Trilogy, large Δ(i) was observed in small MU segments: at 1 MU/segment, the maximum Δ(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 (Δ(i) > 0), while the last segment consistently undershot (Δ(i) accuracy as a function of increasing dose rate on the Trilogy is no longer apparent on TrueBeam, even for dose rates as high as 2400 MU/min. Dose inaccuracy averaged over all ten segments in each beam delivery sequence was larger for Trilogy than TrueBeam, with the largest discrepancy (0.2% vs 3%) occurring for 1 MU

  16. Re-Shielding of Cobalt-60 Teletherapy Rooms for Tomotherapy and Conventional Linear Accelerators using Monte Carlo Simulations

    Science.gov (United States)

    Çeçen, Yiğit; Yazgan, Çağrı

    2017-09-01

    Purpose. Nearly all Cobalt-60 teletherapy machines were removed around the world during the last two decades. The remaining ones are being used for experimental purposes. However, the rooms of these teletherapy machines are valuable because of lack of space in radiotherapy clinics. In order to place a new technology treatment machine in one of these rooms, one should re-shield the room since it was designed only for 1.25 MeV gamma beams on average. Mostly, the vendor of the new machine constructs the new shielding of the room using their experience. However, every radiotherapy room has different surrounding work areas and it would be wise to shield the room considering these special conditions. Also, the shield design goal of the clinic may be much lower than the International Atomic Energy Agency (IAEA) or the local association accepts. The study shows re-shielding of a Cobalt-60 room, specific to the clinic, using Monte Carlo simulations. Materials & Methods: First, a 6 MV Tomotherapy machine, then a 10 MV conventional linear accelerator (LINAC) was placed inside the Cobalt-60 teletherapy room. The photon flux outside the room was simulated using Monte Carlo N-Particle (MCNP6.1) code before and after re-shielding. For the Tomotherapy simulation, flux distributions around the machine were obtained from the vendor and implemented as the source of the model. The LINAC model was more generic with the 10 MeV electron source, the tungsten target, first and secondary collimators. The aim of the model was to obtain the maximum (40x40 cm2) open field at the isocenter. Two different simulations were carried out for gantry angles 90o and 270o. The LINAC was placed in the room such that the primary walls were A' (Gantry 270o) and C' (Gantry 90o) (figure 1). The second part of the study was to model the re-shielding of the room for Tomotherapy and for the conventional LINAC, separately. The aim was to investigate the recommended shielding by the vendors. Left side of the room

  17. 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

  18. Propagation speed, linear stability, and ion acceleration in radially imploding Hall-driven electron-magnetohydrodynamic shocks

    Science.gov (United States)

    Richardson, A. S.; Swanekamp, S. B.; Jackson, S. L.; Mosher, D.; Ottinger, P. F.

    2018-01-01

    Plasma density gradients are known to drive magnetic shocks in electron-magnetohydrodynamics. Previous slab modeling has been extended to cylindrical modeling of radially imploding shocks. The main new effect of the cylindrical geometry is found to be a radial dependence in the speed of shock propagation. This is shown here analytically and in numerical simulations. Ion acceleration by the magnetic shock is shown to possibly become substantial, especially in the peaked structures that develop in the shock because of electron inertia.

  19. Cultural resource survey report for construction of office building, driveway, and parking lot at the Stanford Linear Accelerator Center. Part 1

    Energy Technology Data Exchange (ETDEWEB)

    Perry, M.E.

    1995-01-01

    An Environmental Assessment and associated documentation is reported for the construction of an office building and parking lot in support of environmental management personnel activities. As part of the documentation process, the DOE determined that the proposed project constituted an undertaking as defined in Section 106 of the National Historic Preservation Act. In accordance with the regulations implementing Section 106 of the National Historic Preservation Act, a records and literature search and historic resource identification effort were carried out on behalf of the Stanford Linear Accelerator Center (SLAC). This report summarizes cultural resource literature and record searches and a historic resource identification effort.

  20. Heavy-ion injector based on an electron cyclotron ion source for the superconducting linear accelerator of the Rare Isotope Science Project.

    Science.gov (United States)

    Hong, In-Seok; Kim, Yong-Hwan; Choi, Bong-Hyuk; Choi, Suk-Jin; Park, Bum-Sik; Jin, Hyun-Chang; Kim, Hye-Jin; Heo, Jeong-Il; Kim, Deok-Min; Jang, Ji-Ho

    2016-02-01

    The injector for the main driver linear accelerator of the Rare Isotope Science Project in Korea, has been developed to allow heavy ions up to uranium to be delivered to the inflight fragmentation system. The critical components of the injector are the superconducting electron cyclotron resonance (ECR) ion sources, the radio frequency quadrupole (RFQ), and matching systems for low and medium energy beams. We have built superconducting magnets for the ECR ion source, and a prototype with one segment of the RFQ structure, with the aim of developing a design that can satisfy our specifications, demonstrate stable operation, and prove results to compare the design simulation.

  1. High power operation of the polyphase resonant converter modulator system for the spallation neutron source linear accelerator

    CERN Document Server

    Reass, W A; Baca, D M; Doss, J D; Gonzáles, J M; Gribble, R F; Trujillo, P G

    2003-01-01

    The spallation neutron source (SNS) is a new 1.4 MW average power beam, 1 GeV accelerator being built at Oak Ridge national laboratory. The accelerator requires 15 "long-pulse" converter-modulator stations each providing a maximum of 11 MW pulses with a 1.1 MW average power. Two variants of the converter-modulator are utilized, an 80 kV and a 140 kV design, the voltage dependant on the type of klystron load. The converter-modulator can be described as a resonant zero-voltage- switching polyphase boost inverter. As noted in Figure 1, each converter modulator derives its buss voltage from a standard 13.8 kV to 2100 Y (1.5 MVA) substation cast-core transformer. The substation also contains harmonic traps and filters to accommodate IEEE 519 and 141 regulations. Each substation is followed by an SCR preregulator to accommodate system voltage changes from no load to full load, in addition to providing a soft-start function. Energy storage and filtering is provided by special low inductance self-clearing metallized ...

  2. Measurement of back-scattered radiation from micro multileaf collimator into the beam monitor chamber from a dual energy linear accelerator

    Directory of Open Access Journals (Sweden)

    Muralidhar K

    2007-01-01

    Full Text Available Measurements designed to find the collimator backscatter into the beam monitor chamber from Micro Multileaf collimator of 6 MV photon beams of the Siemens Primus linear accelerator were made with the help of dose rate feedback control. The photons and electrons backscattered from the upper and lower secondary collimator jaws give rise to a significant increase in the ion charge measured by monitor chamber. This increase varies between the different accelerators. The output measurements were carried out in air at the isocenter. The effect of collimator backscatter was investigated by measuring the pulse width, number of beam pulses per monitor unit, monitor unit rate and dose for different mMLC openings. These measurements were made with and without dose rate feedback control, i.e., with constant electron beam current in the accelerator. Monitor unit rate (MU/min was almost constant for all field sizes. The maximum variation between the open and the closed feedback control circuits was 2.5%. There was no difference in pulse width and negligible difference in pulse frequency. Maximum value of backscattered radiation from the micro Multileaf collimator into the beam monitor chamber was found to be 0.5%.

  3. Linear Accelerator Stereotactic Radiosurgery of Central Nervous System Arteriovenous Malformations: A 15-Year Analysis of Outcome-Related Factors in a Single Tertiary Center.

    Science.gov (United States)

    Thenier-Villa, José Luis; Galárraga-Campoverde, Raúl Alejandro; Martínez Rolán, Rosa María; De La Lama Zaragoza, Adolfo Ramón; Martínez Cueto, Pedro; Muñoz Garzón, Víctor; Salgado Fernández, Manuel; Conde Alonso, Cesáreo

    2017-07-01

    Linear accelerator stereotactic radiosurgery is one of the modalities available for the treatment of central nervous system arteriovenous malformations (AVMs). The aim of this study was to describe our 15-year experience with this technique in a single tertiary center and the analysis of outcome-related factors. From 1998 to 2013, 195 patients were treated with linear accelerator-based radiosurgery; we conducted a retrospective study collecting patient- and AVM-related variables. Treatment outcomes were obliteration, posttreatment hemorrhage, symptomatic radiation-induced changes, and 3-year neurologic status. We also analyzed prognostic factors of each outcome and predictability analysis of 5 scales: Spetzler-Martin grade, Lawton-Young supplementary and Lawton combined scores, radiosurgery-based AVM score, Virginia Radiosurgery AVM Scale, and Heidelberg score. Overall obliteration rate was 81%. Nidus diameter and venous drainage were predictive of obliteration (P radiosurgery is a useful, valid, effective, and safe modality for treatment of brain AVMs. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Design of an X-band electron linear accelerator dedicated to decentralized ^{99}Mo/^{99m}Tc supply: From beam energy selection to yield estimation

    Directory of Open Access Journals (Sweden)

    Jaewoong Jang

    2017-10-01

    Full Text Available The most frequently used radionuclide in diagnostic nuclear medicine, ^{99m}Tc, is generally obtained by the decay of its parent radionuclide, ^{99}Mo. Recently, concerns have been raised over shortages of ^{99}Mo/^{99m}Tc, owing to aging of the research reactors which have been supplying practically all of the global demand for ^{99}Mo in a centralized fashion. In an effort to prevent such ^{99}Mo/^{99m}Tc supply disruption and, furthermore, to ameliorate the underlying instability of the centralized ^{99}Mo/^{99m}Tc supply chain, we designed an X-band electron linear accelerator which can be distributed over multiple regions, whereby ^{99}Mo/^{99m}Tc can be supplied with improved accessibility. The electron beam energy was designed to be 35 MeV, at which an average beam power of 9.1 kW was calculated by the following beam dynamics analysis. Subsequent radioactivity modeling suggests that 11 of the designed electron linear accelerators can realize self-sufficiency of ^{99}Mo/^{99m}Tc in Japan.

  5. Design of an X -band electron linear accelerator dedicated to decentralized 99Mo/99mTc supply: From beam energy selection to yield estimation

    Science.gov (United States)

    Jang, Jaewoong; Yamamoto, Masashi; Uesaka, Mitsuru

    2017-10-01

    The most frequently used radionuclide in diagnostic nuclear medicine, 99mTc, is generally obtained by the decay of its parent radionuclide, 99Mo. Recently, concerns have been raised over shortages of 99Mo/99mTc, owing to aging of the research reactors which have been supplying practically all of the global demand for 99Mo in a centralized fashion. In an effort to prevent such 99Mo/99mTc supply disruption and, furthermore, to ameliorate the underlying instability of the centralized 99Mo/99mTc supply chain, we designed an X -band electron linear accelerator which can be distributed over multiple regions, whereby 99Mo/99mTc can be supplied with improved accessibility. The electron beam energy was designed to be 35 MeV, at which an average beam power of 9.1 kW was calculated by the following beam dynamics analysis. Subsequent radioactivity modeling suggests that 11 of the designed electron linear accelerators can realize self-sufficiency of 99Mo/99mTc in Japan.

  6. Scalability of the LEU-Modified Cintichem Process: 3-MeV Van de Graaff and 35-MeV Electron Linear Accelerator Studies

    Energy Technology Data Exchange (ETDEWEB)

    Rotsch, David A. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Brossard, Tom [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Roussin, Ethan [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Quigley, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Chemerisov, Sergey [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Gromov, Roman [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Jonah, Charles [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Hafenrichter, Lohman [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Tkac, Peter [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Krebs, John [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

    2016-10-31

    Molybdenum-99, the mother of Tc-99m, can be produced from fission of U-235 in nuclear reactors and purified from fission products by the Cintichem process, later modified for low-enriched uranium (LEU) targets. The key step in this process is the precipitation of Mo with α-benzoin oxime (ABO). The stability of this complex to radiation has been examined. Molybdenum-ABO was irradiated with 3 MeV electrons produced by a Van de Graaff generator and 35 MeV electrons produced by a 50 MeV/25 kW electron linear accelerator. Dose equivalents of 1.7–31.2 kCi of Mo-99 were administered to freshly prepared Mo-ABO. Irradiated samples of Mo-ABO were processed according to the LEU Modified-Cintichem process. The Van de Graaff data indicated good radiation stability of the Mo-ABO complex up to ~15 kCi dose equivalents of Mo-99 and nearly complete destruction at doses >24 kCi Mo-99. The linear accelerator data indicate that even at 6.2 kCi of Mo-99 equivalence of dose, the sample lost ~20% of Mo-99. The 20% loss of Mo-99 at this low dose may be attributed to thermal decomposition of the product from the heat deposited in the sample during irradiation.

  7. LIBO accelerates

    CERN Multimedia

    2002-01-01

    The prototype module of LIBO, a linear accelerator project designed for cancer therapy, has passed its first proton-beam acceleration test. In parallel a new version - LIBO-30 - is being developed, which promises to open up even more interesting avenues.

  8. PHITS simulations of absorbed dose out-of-field and neutron energy spectra for ELEKTA SL25 medical linear accelerator

    Science.gov (United States)

    Puchalska, Monika; Sihver, Lembit

    2015-06-01

    Monte Carlo (MC) based calculation methods for modeling photon and particle transport, have several potential applications in radiotherapy. An essential requirement for successful radiation therapy is that the discrepancies between dose distributions calculated at the treatment planning stage and those delivered to the patient are minimized. It is also essential to minimize the dose to radiosensitive and critical organs. With MC technique, the dose distributions from both the primary and scattered photons can be calculated. The out-of-field radiation doses are of particular concern when high energy photons are used, since then neutrons are produced both in the accelerator head and inside the patients. Using MC technique, the created photons and particles can be followed and the transport and energy deposition in all the tissues of the patient can be estimated. This is of great importance during pediatric treatments when minimizing the risk for normal healthy tissue, e.g. secondary cancer. The purpose of this work was to evaluate 3D general purpose PHITS MC code efficiency as an alternative approach for photon beam specification. In this study, we developed a model of an ELEKTA SL25 accelerator and used the transport code PHITS for calculating the total absorbed dose and the neutron energy spectra infield and outside the treatment field. This model was validated against measurements performed with bubble detector spectrometers and Boner sphere for 18 MV linacs, including both photons and neutrons. The average absolute difference between the calculated and measured absorbed dose for the out-of-field region was around 11%. Taking into account a simplification for simulated geometry, which does not include any potential scattering materials around, the obtained result is very satisfactorily. A good agreement between the simulated and measured neutron energy spectra was observed while comparing to data found in the literature.

  9. Finite element analysis and frequency shift studies for the bridge coupler of the coupled cavity linear accelerator of the spallation neutron source.

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z. (Zukun)

    2001-01-01

    The Spallation Neutron Source (SNS) is an accelerator-based neutron scattering research facility. The linear accelerator (linac) is the principal accelerating structure and divided into a room-temperature linac and a superconducting linac. The normal conducting linac system that consists of a Drift Tube Linac (DTL) and a Coupled Cavity Linac (CCL) is to be built by Los Alamos National Laboratory. The CCL structure is 55.36-meters long. It accelerates H- beam from 86.8 Mev to 185.6 Mev at operating frequency of 805 MHz. This side coupled cavity structure has 8 cells per segment, 12 segments and 11 bridge couplers per module, and 4 modules total. A 5-MW klystron powers each module. The number 3 and number 9 bridge coupler of each module are connected to the 5-MW RF power supply. The bridge coupler with length of 2.5 {beta}{gamma} is a three-cell structure and located between the segments and allows power flow through the module. The center cell of each bridge coupler is excited during normal operation. To obtain a uniform electromagnetic filed and meet the resonant frequency shift, the RF induced heat must be removed. Thus, the thermal deformation and frequency shift studies are performed via numerical simulations in order to have an appropriate cooling design and predict the frequency shift under operation. The center cell of the bridge coupler also contains a large 4-inch slug tuner and a tuning post that used to provide bulk frequency adjustment and field intensity adjustment, so that produce the proper total field distribution in the module assembly.

  10. Quality control of virtual wedge in a linear electron accelerator with a computerized radiography system (CR); Control de calidad de la cuna virtual en un acelerador lineal de electrones mediante un sistema de radiografia competerizada (CR)

    Energy Technology Data Exchange (ETDEWEB)

    Ordiales, J. M.; Alvarez, F. J.; Falero, B.

    2011-07-01

    For quality control of the virtual wedge there are several systems on the market as arrays of detectors or ionization chambers, linear or 2D configuration, radiochromic films or digital imaging systems incorporated in electron linear accelerators (ALE ). The present work aims at implementing a system of Computed Radiography (CR) for a routine check of the virtual wedge.

  11. FPGASW: Accelerating Large-Scale Smith-Waterman Sequence Alignment Application with Backtracking on FPGA Linear Systolic Array.

    Science.gov (United States)

    Fei, Xia; Dan, Zou; Lina, Lu; Xin, Man; Chunlei, Zhang

    2017-04-21

    The Smith-Waterman (SW) algorithm based on dynamic programming is a well-known classical method for high precision sequence matching and has become the gold standard to evaluate sequence alignment software. In this paper, we propose fine-grained parallelized SW algorithms using affine gap penalty and implement a parallel computing structures to accelerating the SW with backtracking on FPGA platform. We analysis the dynamic parallel computing features of anti-diagonal elements and storage expansion problem resulting from backtracking stage, and propose a series of optimization strategies to eliminate data dependency, reduce storage requirements, and overlap memory access latency. Our implementation is capable of supporting multi-type, large-scale biological sequence alignment applications. We obtain a speedup between 3.6 and 25.2 over the typical SW algorithm running on a general-purpose computer configured with an Intel Core i5 3.2 GHz CPU. Moreover, our work is superior to other FPGA implementations in both array size and clock frequency, and the experiment results show that it can get a performance closed to that of the latest GPU implementation, but the power consumption is only about 26% of that of the GPU platforms.

  12. Use of parallel-plate ionization chambers in reference dosimetry of NOVAC and LIAC(®) mobile electron linear accelerators for intraoperative radiotherapy: a multi-center survey.

    Science.gov (United States)

    Scalchi, Paolo; Ciccotelli, Alessia; Felici, Giuseppe; Petrucci, Assunta; Massafra, Raffaella; Piazzi, Valeria; D'Avenia, Paola; Cavagnetto, Francesca; Cattani, Federica; Romagnoli, Raffaella; Soriani, Antonella

    2017-01-01

    LIAC(®) and NOVAC are two mobile linear accelerators dedicated to intraoperative radiation therapy (IORT), generating electron beams in the energy range of 3-12 MeV. Due to high dose-per-pulse (up to 70 mGy per pulse), in 2003 the Italian National Institute of Health (ISS) stated that "for the measure of dose to water in reference conditions, ionization chambers cannot be employed and no published dosimetry protocol can be used". As a consequence, ferrous sulphate (or, alternatively alanine) dosimetry was recommended. Based on a retrospective multi-center survey, a comparison with ferrous sulphate dosimetry is now used to validate the parallel-plate ionization chambers for reference dosimetry of NOVAC and LIAC. The IAEA TRS-398 dosimetry protocol was applied except for the reference irradiation setup and the determination of the ion-recombination correction factor ks . Moreover the depth of maximum dose (R100 ) instead of zref as measurement depth was chosen by the majority of centers, thus implying a renormalization of the beam-quality correction factor kQ,Qo , based on water-air stopping power ratios. Regarding the ks determination, a previously published method, independent of ferrous sulphate dosimetry, was adopted. All the centers participating in this study had used both ferrous sulphate dosimeters and ionization chambers in water phantoms for dosimetry under reference conditions. The mean percentage difference between ionization chambers and ferrous sulphate dosimetry was -0.5% with a dispersion of 3.9% (2σ). Moreover, the uncertainty analysis allowed the agreement between ionization chambers and ferrous sulphate dosimetry to be verified. These results did not show any significant dependence on electron energy, thus indirectly confirming kQ,Qo renormalization. The results from the centers using zref as the measurement depth were similar to the other data, but further focused studies could aim at investigating possible dependences of the dose differences

  13. Prototype 1.75 MV X-band linear accelerator testing for medical CT and industrial nondestructive testing applications

    Science.gov (United States)

    Clayton, James; Shedlock, Daniel; Vanderet, Steven; Zentai, George; Star-Lack, Josh; LaFave, Richard; Virshup, Gary

    2015-03-01

    Flat panel imagers based on amorphous silicon technology (a-Si) for digital radiography are accepted by the medical and industrial community as having several advantages over radiographic film-based systems. Use of Mega-voltage x-rays with these flat panel systems is applicable to both portal imaging for radiotherapy and for nondestructive testing (NDT) and security applications. In the medical field, one potential application that has not been greatly explored is to radiotherapy treatment planning. Currently, such conventional computed tomographic (CT) data acquired at kV energies is used to help delineate tumor targets and normal structures that are to be spared during treatment. CT number accuracy is crucial for radiotherapy dose calculations. Conventional CT scanners operating at kV X-ray energies typically exhibit significant image reconstruction artifacts in the presence of metal implants in human body. Using the X-ray treatment beams, having energies typically >=6MV, to acquire the CT data may not be practical if it is desired to maintain contrast sensitivity at a sufficiently low dose. Nondestructive testing imaging systems can expand their application space with the development of the higher energy accelerator for use in pipeline, and casting inspection as well as certain cargo screening applications that require more penetration. A new prototype x-band BCL designed to operate up to 1.75 MV has been designed built and tested. The BCL was tested with a prototype portal imager and medical phantoms to determine artifact reductions and a PaxScan 2530HE industrial imager to demonstrate resolution is maintained and penetration is improved.

  14. Commissioning and quality assurance of the X-ray volume Imaging system of an image-guided radiotherapy capable linear accelerator

    Directory of Open Access Journals (Sweden)

    Muralidhar K

    2008-01-01

    Full Text Available An Image-Guided Radiotherapy-capable linear accelerator (Elekta Synergy was installed at our hospital, which is equipped with a kV x-ray volume imaging (XVI system and electronic portal imaging device (iViewGT. The objective of this presentation is to describe the results of commissioning measurements carried out on the XVI facility to verify the manufacturer′s specifications and also to evolve a QA schedule which can be used to test its performance routinely. The QA program consists of a series of tests (safety features, geometric accuracy, and image quality. These tests were found to be useful to assess the performance of the XVI system and also proved that XVI system is very suitable for image-guided high-precision radiation therapy.

  15. Measurement of photoneutron doses in and out of high-energy X-ray beam of a SATURNE-20 medical linear accelerator by ECE polycarbonate detectors

    CERN Document Server

    Sohrabi, M

    1999-01-01

    Photoneutron contaminations in and out of high energy X-ray beams of the medical linear accelerator SATURNE 20 (CGR) of the Radiotherapy Department of Omeed Hospital in Isfahan, Iran, have been determined using 250 mu m polycarbonate (PC) dosimeters, in strips or in sheets, processed by electrochemical etching (ECE) using specially designed ECE chambers to etch larger sheets. A two dimensional or topographical distribution of neutron contamination was also determined in a full size beam. The neutron dose equivalents (Hn) in the beam of 18 MV X-rays at 80 cm FSD were determined to be linear functions of X-ray dose equivalents (Hx) up to 1400 cSv. The distribution of the Hn at different X-ray doses showed bell-shape profiles with maxima at the isocenter. The ratios of dose equivalents of neutrons to those of X-rays increased as the field size increased having values of 0.22%, 0.28%, 0.31% and 0.37% for field sizes of 10x10, 20x20, 30x30, and 40x40 cm sup 2 respectively. Although such neutron dose equivalents ca...

  16. Measurements of photon and neutron leakage from medical linear accelerators and Monte Carlo simulation of tenth value layers of concrete used for intensity modulated radiation therapy treatment

    Science.gov (United States)

    Jaradat, Adnan Khalaf

    The x ray leakage from the housing of a therapy x ray source is regulated to be measured from linacs operating at 4, 6, 10, 15, and 18 MV using a 100 cm3 ionization chamber and track-etch detectors. The leakage was measured at nine different positions over the rear wall using a 3 x 3 matrix with a 1 m separation between adjacent positions. In general, the leakage was less than the canonical value, but the exact value depends on energy, gantry angle, and measurement position. Leakage at 10 MV for some positions exceeded 0.1%. Electrons with energy greater than about 9 MeV have the ability to produce neutrons. Neutron leakage has been measured around the head of electron accelerators at a distance 1 m from the target at 0°, 46°, 90°, 135°, and 180° azimuthal angles; for electron energies of 9, 12, 15, 16, 18, and 20 MeV and 10, 15, and 18 MV x ray photon beam, using a neutron bubble detector of type BD-PND and using Track-Etch detectors. The highest neutron dose equivalent per unit electron dose was at 0° for all electron energies. The neutron leakage from photon beams was the highest between all the machines. Intensity modulated radiation therapy (IMRT) delivery consists of a summation of small beamlets having different weights that make up each field. A linear accelerator room designed exclusively for IMRT use would require different, probably lower, tenth value layers (TVL) for determining the required wall thicknesses for the primary barriers. The first, second, and third TVL of 60Co gamma rays and photons from 4, 6, 10, 15, and 18 MV x ray beams by concrete have been determined and modeled using a Monte Carlo technique (MCNP version 4C2) for cone beams of half-opening angles of 0°, 3°, 6°, 9°, 12°, and 14°.

  17. Study on the measurement of photo-neutron for15 MV photon beam from medical linear accelerator under different irradiation geometries using passive detectors.

    Science.gov (United States)

    Thekkedath, Siji Cyriac; Raman, R Ganapathi; Musthafa, M M; Bakshi, A K; Pal, Rupali; Dawn, Sandipan; Kummali, Abdul Haneefa; Huilgol, Nagraj G; Selvam, T Palani; Datta, D

    2016-01-01

    The photo-neutron dose equivalents of 15 MV Elekta precise accelerators were measured for different depths in phantom, for various field sizes, at different distances from the isocenter in the patient plane and for various wedged fields. Fast and thermal neutrons are measured using passive detectors such as Columbia Resin-39 and pair of thermoluminescent dosimetry (TLD) 600 and TLD 700 detector from Elekta medical linear accelerator. It is found that fast photo-neutron dose rate decreases as the depth increases, with a maximum of 0.57 ± 0.08 mSv/Gy photon dose at surface and minimum of 0.09 ± 0.02 mSv/Gy photon dose at 15 cm depth of water equivalent phantom with 10 cm backscatter. Photo neutrons decreases from 1.28 ± 0.03 mSv/Gy to 0.063 ± 0.032 when measured at isocenter and at 100 cm far from the field edge along the longitudinal direction in the patient plane. Fast and thermal neutron doses increases from 0.65 ± 0.05 mSv/Gy to 1.08 ± 0.07 mSv/Gy as the field size increases; from 5 cm × 5 cm to 30 cm × 30 cm for fast neutrons. With increase in wedge field angle from 0° to 60°, it is observed that the fast neutron dose increases from 0.42 ± 0.03 mSv/Gy to 0.95 ± 0.05 mSv/Gy.s Measurements indicate the photo-neutrons at few field sizes are slightly higher than the International Electrotechnical Commission standard specifications. Photo-neutrons from Omni wedged fields are studied in details. These studies of the photo-neutron energy response will enlighten the neutron dose to radiation therapy patients and are expected to further improve radiation protection guidelines.

  18. Intraoperative Radiation Therapy in Early Breast Cancer Using a Linear Accelerator Outside of the Operative Suite: An “Image-Guided” Approach

    Energy Technology Data Exchange (ETDEWEB)

    Hanna, Samir Abdallah, E-mail: samir.hanna@hsl.org.br [Department of Radiation Oncology, Hospital Sirio-Libanes, Sao Paulo (Brazil); Simões Dornellas de Barros, Alfredo Carlos; Martins de Andrade, Felipe Eduardo; Barbosa Bevilacqua, Jose Luiz [Department of Mastology, Hospital Sirio-Libanes, Sao Paulo (Brazil); Morales Piato, José Roberto [Department of Mastology, Hospital Sirio-Libanes, Sao Paulo (Brazil); Department of Gynecology, Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, Sao Paulo (Brazil); Lopes Pelosi, Edilson [Department of Radiation Oncology, Hospital Sirio-Libanes, Sao Paulo (Brazil); Martella, Eduardo [Department of Radiation Oncology, Hospital Perola Byington, Sao Paulo (Brazil); Fernandes da Silva, João Luis [Department of Radiation Oncology, Hospital Sirio-Libanes, Sao Paulo (Brazil); Andrade Carvalho, Heloisa de [Department of Radiation Oncology, Hospital Sirio-Libanes, Sao Paulo (Brazil); Department of Radiology and Oncology, Faculdade de Medicina da Universidade de Sao Paulo, Sao Paulo (Brazil)

    2014-08-01

    Purpose: To present local control, complications, and cosmetic outcomes of intraoperative radiation therapy (IORT) for early breast cancer, as well as technical aspects related to the use of a nondedicated linear accelerator. Methods and Materials: This prospective trial began in May of 2004. Eligibility criteria were biopsy-proven breast-infiltrating ductal carcinoma, age >40 years, tumor <3 cm, and cN0. Exclusion criteria were in situ or lobular types, multicentricity, skin invasion, any contraindication for surgery and/or radiation therapy, sentinel lymph node involvement, metastasis, or another malignancy. Patients underwent classic quadrantectomy with intraoperative sentinel lymph node and margins evaluation. If both free, the patient was transferred from operative suite to linear accelerator room, and IORT was delivered (21 Gy). Primary endpoint: local recurrence (LR); secondary endpoints: toxicities and aesthetics. Quality assurance involved using a customized shield for chest wall protection, applying procedures to minimize infection caused by patient transportation, and using portal films to check collimator-shield alignment. Results: A total of 152 patients were included, with at least 1 year follow-up. Median age (range) was 58.3 (40-85.4) years, and median follow-up time was 50.7 (12-110.5) months. The likelihood of 5-year local recurrence was 3.7%. There were 3 deaths, 2 of which were cancer related. The Kaplan-Meier 5-year actuarial estimates of overall, disease-free, and local recurrence-free survivals were 97.8%, 92.5%, and 96.3%, respectively. The overall incidences of acute and late toxicities were 12.5% and 29.6%, respectively. Excellent, good, fair, and bad cosmetic results were observed in 76.9%, 15.8%, 4.3%, and 2.8% of patients, respectively. Most treatments were performed with a 5-cm collimator, and in 39.8% of the patients the electron-beam energy used was ≥12 MeV. All patients underwent portal film evaluation, and the shielding was

  19. SU-F-T-631: Linear Accelerator-Based Frameless Extracranial Radiosurgery for Treatment of Occipital Neuralgia for Non-Surgical Candidates

    Energy Technology Data Exchange (ETDEWEB)

    Denton, T; Howe, J [Associates In Medical Physics, Louisville, KY (United States); Spalding, A [The Norton Cancer Institute Radiation Center, Louisville, KY (United States)

    2016-06-15

    Purpose: Occipital neuralgia is a condition wherein pain is transmitted by the occipital nerves. Non-invasive therapies generally alleviate symptoms; however, persistent or recurring pain may require invasive procedures. Repeated invasive procedures upon failure are considered higher risk and are often contraindicated due to compounding inherent risk. SRS has not been explored as a treatment option largely due to the extracranial nature of the target (as opposed to the similar, more established trigeminal neuralgia), but advances in linear-accelerator frameless-based SRS now present an opportunity to evaluate the novel potential of this modality for this application. Methods: Patient presented with severe occipital pain following decompression and fusion of the cervical vertebrae with prior intervention attempted via radiofrequency ablation yielding temporary pain cessation. A 0.6 mm slice spacing CT was obtained for treatment planning, and a cervical spine oriented 1.0 mm slice spacing CT myelogram was obtained for the purpose of defining the targeted C2 occipital dorsal root ganglion (to receive 80 Gy to the isocenter) and spinal cord. Results: The spinal cord was most proximally 12.0 mm from the isocenter receiving a maximum dose of 3.36 Gy, and doses to 0.35 and 1.2 cc of 1.84 Gy and 0.79 Gy, respectively. The brain maximum dose was 2.29 Gy. The treatment was successfully performed with a NovalisTX (Varian) equipped with ExacTrac stereoscopic x-ray image guidance (BrainLAB). Treatment time was 59 minutes for 18,323 MUs. Imaging was performed prior to each arc delivery resulting in twenty-one imaging sessions (twelve requiring positional corrections with the remaining verified within tolerance). The average deviation magnitude requiring a positional or rotational correction was 0.96±0.25 mm, 0.8±0.41° while the average deviation magnitude deemed within tolerance was 0.41±0.12 mm, 0.57±0.28°. Conclusion: Linear accelerator-based frameless radiosurgery

  20. Reconstruction of X-rays spectra of clinical linear accelerators using the generalized simulated annealing method; Reconstrucao de espectros de raios-X de aceleradores lineares clinicos usando o metodo de recozimento simulado generalizado

    Energy Technology Data Exchange (ETDEWEB)

    Manrique, John Peter O.; Costa, Alessandro M., E-mail: johnp067@usp.br, E-mail: amcosta@usp.br [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil)

    2016-07-01

    The spectral distribution of megavoltage X-rays used in radiotherapy departments is a fundamental quantity from which, in principle, all relevant information required for radiotherapy treatments can be determined. To calculate the dose delivered to the patient who make radiation therapy, are used treatment planning systems (TPS), which make use of convolution and superposition algorithms and which requires prior knowledge of the photon fluence spectrum to perform the calculation of three-dimensional doses and thus ensure better accuracy in the tumor control probabilities preserving the normal tissue complication probabilities low. In this work we have obtained the photon fluence spectrum of X-ray of the SIEMENS ONCOR linear accelerator of 6 MV, using an character-inverse method to the reconstruction of the spectra of photons from transmission curves measured for different thicknesses of aluminum; the method used for reconstruction of the spectra is a stochastic technique known as generalized simulated annealing (GSA), based on the work of quasi-equilibrium statistic of Tsallis. For the validation of the reconstructed spectra we calculated the curve of percentage depth dose (PDD) for energy of 6 MV, using Monte Carlo simulation with Penelope code, and from the PDD then calculate the beam quality index TPR{sub 20/10}. (author)

  1. Induction accelerators

    CERN Document Server

    Takayama, Ken

    2011-01-01

    A broad class of accelerators rests on the induction principle whereby the accelerating electrical fields are generated by time-varying magnetic fluxes. Particularly suitable for the transport of bright and high-intensity beams of electrons, protons or heavy ions in any geometry (linear or circular) the research and development of induction accelerators is a thriving subfield of accelerator physics. This text is the first comprehensive account of both the fundamentals and the state of the art about the modern conceptual design and implementation of such devices. Accordingly, the first part of the book is devoted to the essential features of and key technologies used for induction accelerators at a level suitable for postgraduate students and newcomers to the field. Subsequent chapters deal with more specialized and advanced topics.

  2. Promoting Success of Ethnic Minority and Male Students in an Accelerated, Entry-Level Master of Nursing Program: The SUSTAIN Program.

    Science.gov (United States)

    Cowan, Patricia A; Weeks, Y'Esha; Wicks, Mona Newsome

    2015-09-01

    Diverse health care workers are essential to meet the needs of a diverse U.S. Ethnic minorities and men are frequently underrepresented in the nursing profession and within schools of nursing. Although many nursing schools have implemented programs to improve retention and academic success of these students, the lack of success is, in part, a reflection of program ineffectiveness. A nursing college developed the multifaceted SUSTAIN (Scholarships for Underrepresented Students in an Accelerated Initial Nursing) program to promote ethnic minority and male students' success in an accelerated entry-level master of nursing program. Students engaged in mentoring, academic support, and service-learning activities. Participants (N = 51) achieved 100% retention and graduation rates and a 92% first-time NCLEX-RN(®) examination pass rate. Program students participated in professional organizations and held leadership roles within the college. Implementation of a program focused on student retention and success is recommended for diverse students enrolled in accelerated entry-level master of nursing programs. Copyright 2015, SLACK Incorporated.

  3. Effect of Die Head Temperature at Compounding Stage on the Degradation of Linear Low Density Polyethylene/Plastic Film Waste Blends after Accelerated Weathering

    Directory of Open Access Journals (Sweden)

    S. M. Al-Salem

    2016-01-01

    Full Text Available Accelerated weathering test was performed on blends of linear low density polyethylene (LLDPE and plastic film waste constituting the following percentages of polyolefin polymers (wt.%: LLDPE (46%, low density polyethylene (LDPE, 51%, high density polyethylene (HDPE, 1%, and polypropylene (PP, 2%. Compounded blends were evaluated for their mechanical and physical (optical properties. The impact of photodegradation on the formulated blends was studied, and loss of mechanical integrity was apparent with respect to both the exposure duration to weathering and waste content. The effect of processing conditions, namely, the die head temperature (DHT of the blown-film assembly used, was investigated in this work. It was witnessed that surpassing the melting point of the blends constituting polymers did not always result in a synergistic behaviour between polymers. This was suspected to be due to the loss of amorphous region that polyolefin polymers get subjected to with UV exposure under weathering conditions and the effect of the plastic waste constituents. The total change in colour (ΔE did not change with respect to DHT or waste content due to rapid change degradation on the material’s surface. Haze (% and light transmission (% decreased with the increase in waste content which was attributed to lack of miscibility between constituting polymers.

  4. Calculation of 10 MV x-ray spectra emitted by a medical linear accelerator using the BFGS quasi-Newton method

    Science.gov (United States)

    Shimozato, T.; Tabushi, K.; Kitoh, S.; Shiota, Y.; Hirayama, C.; Suzuki, S.

    2007-01-01

    To calculate photon spectra for a 10 MV x-ray beam emitted by a medical linear accelerator, we performed numerical analysis using the aluminium transmission data obtained along the central axis of the beam under the narrow beam condition corresponding to a 3 × 3 cm2 field at a 100 cm distance from the source. We used the BFGS quasi-Newton method based on a general nonlinear optimization technique for the numerical analysis. The attenuation coefficients, aluminium thicknesses and measured transmission data are necessary inputs for the numerical analysis. The calculated x-ray spectrum shape was smooth in the lower to higher energy regions without any angular components. The x-ray spectrum acquired by the employed method was evaluated by comparing the measurements along the central axis percentage depth dose in a water phantom and by a Monte Carlo simulation code, the electron gamma shower code. The values of the calculated percentage depth doses for a 10 × 10 cm2 field at a 100 cm source-to-surface distance in a water phantom were obtained using the same geometry settings as those of the water phantom measurement. The differences in the measured and calculated values were less than ±1.0% for a broad region from the shallow part near the surface to deep parts of up to 25 cm in the water phantom.

  5. Effect of the electron transport through thin slabs on the simulation of linear electron accelerators of use in therapy: A comparative study of various Monte Carlo codes

    Energy Technology Data Exchange (ETDEWEB)

    Vilches, M. [Servicio de Fisica y Proteccion Radiologica, Hospital Regional Universitario ' Virgen de las Nieves' , Avda. de las Fuerzas Armadas, 2, E-18014 Granada (Spain)], E-mail: mvilches@ugr.es; Garcia-Pareja, S. [Servicio de Radiofisica Hospitalaria, Hospital Regional Universitario ' Carlos Haya' , Avda. Carlos Haya, s/n, E-29010 Malaga (Spain); Guerrero, R. [Servicio de Radiofisica, Hospital Universitario ' San Cecilio' , Avda. Dr. Oloriz, 16, E-18012 Granada (Spain); Anguiano, M.; Lallena, A.M. [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, E-18071 Granada (Spain)

    2007-09-21

    When a therapeutic electron linear accelerator is simulated using a Monte Carlo (MC) code, the tuning of the initial spectra and the renormalization of dose (e.g., to maximum axial dose) constitute a common practice. As a result, very similar depth dose curves are obtained for different MC codes. However, if renormalization is turned off, the results obtained with the various codes disagree noticeably. The aim of this work is to investigate in detail the reasons of this disagreement. We have found that the observed differences are due to non-negligible differences in the angular scattering of the electron beam in very thin slabs of dense material (primary foil) and thick slabs of very low density material (air). To gain insight, the effects of the angular scattering models considered in various MC codes on the dose distribution in a water phantom are discussed using very simple geometrical configurations for the LINAC. The MC codes PENELOPE 2003, PENELOPE 2005, GEANT4, GEANT3, EGSnrc and MCNPX have been used.

  6. 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)

  7. CPU time optimization and precise adjustment of the Geant4 physics parameters for a VARIAN 2100 C/D gamma radiotherapy linear accelerator simulation using GAMOS.

    Science.gov (United States)

    Arce, Pedro; Lagares, Juan Ignacio

    2017-12-19

    We have verified the GAMOS/Geant4 simulation model of a 6 MV VARIAN 2100 linear accelerator by the procedure of adjusting the initial beam parameters to fit the Percentage Depth Dose and Cross Profile Dose experimental data at different depths in a water phantom. Thanks to the use of a wide range of field sizes, from 2x2 cm2 to 40x40 cm2, a small phantom voxel size and high statistics, a fine precision in the determination of the beam parameters have been achieved. This precision has allowed us to make a thorough study of the different physics models and parameters that Geant4 offers. The three Geant4 electromagnetic physics sets of models, i.e. standard, Livermore and Penelope, have been compared to the experiment, testing the four different models of angular bremsstrahlung distributions as well as the three available multiple scattering models, and optimizing the most relevant Geant4 electromagnetic physics parameters. Before the fitting a thorough CPU time optimization has been done, using several of the Geant4 efficiency improvement techniques plus a few more developed in GAMOS. © 2017 Institute of Physics and Engineering in Medicine.

  8. CPU time optimization and precise adjustment of the Geant4 physics parameters for a VARIAN 2100 C/D gamma radiotherapy linear accelerator simulation using GAMOS

    Science.gov (United States)

    Arce, Pedro; Lagares, Juan Ignacio

    2018-02-01

    We have verified the GAMOS/Geant4 simulation model of a 6 MV VARIAN Clinac 2100 C/D linear accelerator by the procedure of adjusting the initial beam parameters to fit the percentage depth dose and cross-profile dose experimental data at different depths in a water phantom. Thanks to the use of a wide range of field sizes, from 2  ×  2 cm2 to 40  ×  40 cm2, a small phantom voxel size and high statistics, fine precision in the determination of the beam parameters has been achieved. This precision has allowed us to make a thorough study of the different physics models and parameters that Geant4 offers. The three Geant4 electromagnetic physics sets of models, i.e. Standard, Livermore and Penelope, have been compared to the experiment, testing the four different models of angular bremsstrahlung distributions as well as the three available multiple-scattering models, and optimizing the most relevant Geant4 electromagnetic physics parameters. Before the fitting, a comprehensive CPU time optimization has been done, using several of the Geant4 efficiency improvement techniques plus a few more developed in GAMOS.

  9. Expanding the spectrum of phenotypes associated with germline PIGA mutations: a child with developmental delay, accelerated linear growth, facial dysmorphisms, elevated alkaline phosphatase, and progressive CNS abnormalities.

    Science.gov (United States)

    van der Crabben, Saskia N; Harakalova, Magdalena; Brilstra, Eva H; van Berkestijn, Frédérique M C; Hofstede, Floris C; van Vught, Adrianus J; Cuppen, Edwin; Kloosterman, Wigard; Ploos van Amstel, Hans Kristian; van Haaften, Gijs; van Haelst, Mieke M

    2014-01-01

    Phosphatidyl inositol glycan (PIG) enzyme subclasses are involved in distinct steps of glycosyl phosphatidyl inositol anchor protein biosynthesis. Glycolsyl phosphatidyl inositol-anchored proteins have heterogeneous functions; they can function as enzymes, adhesion molecules, complement regulators and co-receptors in signal transduction pathways. Germline mutations in genes encoding different members of the PIG family result in diverse conditions with (severe) developmental delay, (neonatal) seizures, hypotonia, CNS abnormalities, growth abnormalities, and congenital abnormalities as hallmark features. The variability of clinical features resembles the typical diversity of other glycosylation pathway deficiencies such as the congenital disorders of glycosylation. Here, we report the first germline missense mutation in the PIGA gene associated with accelerated linear growth, obesity, central hypotonia, severe refractory epilepsy, cardiac anomalies, mild facial dysmorphic features, mildly elevated alkaline phosphatase levels, and CNS anomalies consisting of progressive cerebral atrophy, insufficient myelinization, and cortical MRI signal abnormalities. X-exome sequencing in the proband identified a c.278C>T (p.Pro93Leu) mutation in the PIGA gene. The mother and maternal grandmother were unaffected carriers and the mother showed 100% skewing of the X-chromosome harboring the mutation. These results together with the clinical similarity of the patient reported here and the previously reported patients with a germline nonsense mutation in PIGA support the determination that this mutation caused the phenotype in this family. © 2013 Wiley Periodicals, Inc.

  10. Biological responses of human solid tumor cells to X-ray irradiation within a 1.5-Tesla magnetic field generated by a magnetic resonance imaging–linear accelerator

    NARCIS (Netherlands)

    Wang, Li; Hoogcarspel, Stan Jelle; Wen, Zhifei; van Vulpen, Marco; Molkentine, David P.; Kok, Jan; Lin, Steven H.; Broekhuizen, Roel; Ang, Kie Kian; Bovenschen, Niels; Raaymakers, Bas W.; Frank, Steven J.

    2016-01-01

    Devices that combine magnetic resonance imaging with linear accelerators (MRL) represent a novel tool for MR-guided radiotherapy. However, whether magnetic fields (MFs) generated by these devices affect the radiosensitivity of tumors is unknown. We investigated the influence of a 1.5-T MF on cell

  11. Verificação do fator de calibração e indicador da qualidade do feixe de aceleradores lineares Verification of dose output and beam quality indicator in linear accelerators

    Directory of Open Access Journals (Sweden)

    Maria da Penha Silva

    2001-10-01

    Full Text Available Um programa de garantia da qualidade é um pré-requisito obrigatório para a exatidão necessária em radioterapia. Este trabalho relata parte dos testes de rotina mensal do controle da qualidade dos aceleradores lineares do Instituto Nacional do Câncer, relativos à calibração dos feixes de fótons e elétrons, no período de dois anos. Os resultados foram comparados com as recomendações do protocolo AAPM TG-40. Na análise do fator de calibração para o feixe de fótons foi encontrado um desvio máximo de 12%; para o feixe de elétrons o maior desvio encontrado foi 10%. A flutuação observada no indicador da qualidade do feixe para os feixes de elétrons foi maior que para os feixes de fótons. Os resultados confirmam a importância de um programa de garantia da qualidade em um serviço de radioterapia, permitindo correções rápidas da dose administrada ao paciente.A quality assurance program is a mandatory prerequisite for obtaining the high level of accuracy required for radiotherapy. This paper reports the results of part of the routine quality control tests for linear accelerators at the National Cancer Institute, Brazil, performed monthly over a period of two years. These tests included dose output and beam quality indicator. The results were compared with the guidelines of the AAPM TG-40 protocol. The results for the photon beams have shown dose output variations of up to 12%; for electron beams, the largest deviation found was 10%. The fluctuations observed in the beam quality indicator for the electron beams were greater than for the photon beams. These results strongly emphasize the importance of a quality assurance program in radiotherapy services in order to allow prompt corrections of the dose delivered to the patient.

  12. SU-E-T-268: Evaluation of Photoneutron Contamination in Elekta Synergy-S High-Energy Linear Accelerator and Indigenous Novel Solution: The AIIMS Experience.

    Science.gov (United States)

    Subramani, V; Singh, M; Sharma, S; Bisht, R; Gopishankar, N; Rath, G

    2012-06-01

    The photoneutron contamination problem was encountered due to laminated barrier wall and short maze. The purpose of this study was to report our experience in evaluating the photoneutron contamination during radiation safety survey and solution. The photoneutron contamination measurement was carried out in Elekta Synergy-S high-energylinear accelerator for 15MV beam. A NE Neutron survey meter and for photon, Victoreen and RADOS survey meters were used. The laminated barrier wall composed of 37cm steel with 30cm concrete both side and short maze length of 5 meter. During safety survey, higher photoneutron levels for 15MV X-rays at treatment room door found. The effect of photoneutron contamination as function of neutron shielding materials of wood, polyethylene and boron and thickness, distance, locations and directions to the control console at distance upto 7 meter were investigated for 4 gantry angles at locations of treatment room entry doors namely door1(A), door2(B), console(C), conduit (D) and above-ceiling(G) for 15MV. The initial safety survey showed that neutron level of 47mR/h and photon leakage of 3.2mR/hr at the treatment entry room door1. The neutron values could bring down to the level of acceptance at the treatment entry door2, but the photon values are not acceptable. Therefore, 30cm concrete wall block was made at the location of door2 and another bend was taken. Finally, treatment entrance room door was made using 3cm polyethylene neutron shielding materials in order to achieve the both neutron contamination and photon leakage within the acceptable levels. The neutron sliding-door is operated manually in finger-push by technologist for day-to-day usage. This simple solution is cost effective and increases the patient throughput. This study underlines that one needs to take appropriate safety measures prior to facility design whenever the space constraints situations arises for high energy linear accelerator. © 2012 American Association of

  13. On-line estimations of delivered radiation doses in three-dimensional conformal radiotherapy treatments of carcinoma uterine cervix patients in linear accelerator

    Directory of Open Access Journals (Sweden)

    Suman Kumar Putha

    2016-01-01

    Full Text Available Transmission of radiation fluence through patient′s body has a correlation to the planned target dose. A method to estimate the delivered dose to target volumes was standardized using a beam level 0.6 cc ionization chamber (IC positioned at electronic portal imaging device (EPID plane from the measured transit signal (S t in patients with cancer of uterine cervix treated with three-dimensional conformal radiotherapy (3DCRT. The IC with buildup cap was mounted on linear accelerator EPID frame with fixed source to chamber distance of 146.3 cm, using a locally fabricated mount. S t s were obtained for different water phantom thicknesses and radiation field sizes which were then used to generate a calibration table against calculated midplane doses at isocenter (D iso,TPS , derived from the treatment planning system. A code was developed using MATLAB software which was used to estimate the in vivo dose at isocenter (D iso,Transit from the measured S t s. A locally fabricated pelvic phantom validated the estimations of D iso,Transit before implementing this method on actual patients. On-line dose estimations were made (3 times during treatment for each patient in 24 patients. The D iso,Transit agreement with D iso,TPS in phantom was within 1.7% and the mean percentage deviation with standard deviation is −1.37% ±2.03% (n = 72 observed in patients. Estimated in vivo dose at isocenter with this method provides a good agreement with planned ones which can be implemented as part of quality assurance in pelvic sites treated with simple techniques, for example, 3DCRT where there is a need for documentation of planned dose delivery.

  14. SU-D-201-01: A Multi-Institutional Study Quantifying the Impact of Simulated Linear Accelerator VMAT Errors for Nasopharynx

    Energy Technology Data Exchange (ETDEWEB)

    Pogson, E [Institute of Medical Physics, The University of Sydney, Sydney, NSW (Australia); Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW (Australia); Ingham Institute for Applied Medical Research, Sydney, NSW (Australia); Hansen, C [Laboratory of Radiation Physics, Odense University Hospital, Odense (Denmark); Institute of Clinical Research, University of Southern Denmark, Odense (Denmark); Blake, S; Thwaites, D [Institute of Medical Physics, The University of Sydney, Sydney, NSW (Australia); Arumugam, S; Juresic, J; Ochoa, C; Yakobi, J; Haman, A; Trtovac, A [Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW (Australia); Holloway, L [Institute of Medical Physics, The University of Sydney, Sydney, NSW (Australia); Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW (Australia); Ingham Institute for Applied Medical Research, Sydney, NSW (Australia); South Western Sydney Clinical School, University of New South Wales, Sydney, NSW (Australia); University of Wollongong, Wollongong, NSW (Australia)

    2016-06-15

    Purpose: To quantify the impact of differing magnitudes of simulated linear accelerator errors on the dose to the target volume and organs at risk for nasopharynx VMAT. Methods: Ten nasopharynx cancer patients were retrospectively replanned twice with one full arc VMAT by two institutions. Treatment uncertainties (gantry angle and collimator in degrees, MLC field size and MLC shifts in mm) were introduced into these plans at increments of 5,2,1,−1,−2 and −5. This was completed using an in-house Python script within Pinnacle3 and analysed using 3DVH and MatLab. The mean and maximum dose were calculated for the Planning Target Volume (PTV1), parotids, brainstem, and spinal cord and then compared to the original baseline plan. The D1cc was also calculated for the spinal cord and brainstem. Patient average results were compared across institutions. Results: Introduced gantry angle errors had the smallest effect of dose, no tolerances were exceeded for one institution, and the second institutions VMAT plans were only exceeded for gantry angle of ±5° affecting different sided parotids by 14–18%. PTV1, brainstem and spinal cord tolerances were exceeded for collimator angles of ±5 degrees, MLC shifts and MLC field sizes of ±1 and beyond, at the first institution. At the second institution, sensitivity to errors was marginally higher for some errors including the collimator error producing doses exceeding tolerances above ±2 degrees, and marginally lower with tolerances exceeded above MLC shifts of ±2. The largest differences occur with MLC field sizes, with both institutions reporting exceeded tolerances, for all introduced errors (±1 and beyond). Conclusion: The plan robustness for VMAT nasopharynx plans has been demonstrated. Gantry errors have the least impact on patient doses, however MLC field sizes exceed tolerances even with relatively low introduced errors and also produce the largest errors. This was consistent across both departments. The authors

  15. Evaluation of linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) for cerebral cavernous malformations: a 15-year single-center experience.

    Science.gov (United States)

    Sager, Omer; Beyzadeoglu, Murat; Dincoglan, Ferrat; Uysal, Bora; Gamsiz, Hakan; Demiral, Selcuk; Oysul, Kaan; Dirican, Bahar; Sirin, Sait

    2014-01-01

    Surgery is the principal treatment for safely accessible hemorrhagic and symptomatic cavernous malformations. Nevertheless, the role of linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) in the management of high-risk, symptomatic cavernoma lesions warrants further refinement. In this study, we evaluate the use of LINAC-based SRS for cerebral cavernous malformations (CMs) and report our 15-year single-center experience. A retrospective study from the Department of Radiation Oncology and the Department of Neurosurgery at Gulhane Military Medical Academy and Medical Faculty, Ankara from April 1998 to June 2013. Fifty-two patients (22 females and 30 males) with cerebral CM referred to our department underwent high-precision single-dose SRS using a LINAC with 6-MV photons. All patients had at least 1 bleeding episode prior to radiosurgery along with related symptoms. Median dose prescribed to the 85% to 95% isodose line encompassing the target volume was 15 Gy (range, 10-20). Out of the total 52 patients, follow-up data were available for 47 patients (90.4%). Median age was 35 years (range, 19-63). Median follow-up time was 5.17 years (range, 0.08-9.5) after SRS. Three hemorrhages were identified in the post-SRS period. Statistically significant decrease was observed in the annual hemorrhage rate after radiosurgical treatment (pre-SRS 39% vs post-SRS 1.21, P cerebral CM of selected patients with prior bleeding from lesions located at surgically inaccessible or eloquent brain areas.

  16. 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.

  17. Development of an ultrasmall C-band linear accelerator guide for a four-dimensional image-guided radiotherapy system with a gimbaled x-ray head.

    Science.gov (United States)

    Kamino, Yuichiro; Miura, Sadao; Kokubo, Masaki; Yamashita, Ichiro; Hirai, Etsuro; Hiraoka, Masahiro; Ishikawa, Junzo

    2007-05-01

    We are developing a four-dimensional image-guided radiotherapy system with a gimbaled x-ray head. It is capable of pursuing irradiation and delivering irradiation precisely with the help of an agile moving x-ray head on the gimbals. Requirements for the accelerator guide were established, system design was developed, and detailed design was conducted. An accelerator guide was manufactured and basic beam performance and leakage radiation from the accelerator guide were evaluated at a low pulse repetition rate. The accelerator guide including the electron gun is 38 cm long and weighs about 10 kg. The length of the accelerating structure is 24.4 cm. The accelerating structure is a standing wave type and is composed of the axial-coupled injector section and the side-coupled acceleration cavity section. The injector section is composed of one prebuncher cavity, one buncher cavity, one side-coupled half cavity, and two axial coupling cavities. The acceleration cavity section is composed of eight side-coupled nose reentrant cavities and eight coupling cavities. The electron gun is a diode-type gun with a cerium hexaboride (CeB6) direct heating cathode. The accelerator guide can be operated without any magnetic focusing device. Output beam current was 75 mA with a transmission efficiency of 58%, and the average energy was 5.24 MeV. Beam energy was distributed from 4.95 to 5.6 MeV. The beam profile, measured 88 mm from the beam output hole on the axis of the accelerator guide, was 0.7 mm X 0.9 mm full width at half maximum (FWHM) width. The beam loading line was 5.925 (MeV)-Ib (mA) X 0.00808 (MeV/mA), where Ib is output beam current. The maximum radiation leakage of the accelerator guide at 100 cm from the axis of the accelerator guide was calculated as 0.33 cGy/min at the rated x-ray output of 500 cGy/min from the measured value. This leakage requires no radiation shielding for the accelerator guide itself per IEC 60601-2-1.

  18. Generation and verification of QFix kVue Calypso-compatible couch top model for a dedicated stereotactic linear accelerator with FFF beams.

    Science.gov (United States)

    Gardner, Stephen J; Gulam, Misbah; Song, Kwang; Li, Haisen; Huang, Yimei; Zhao, Bo; Qin, Yujiao; Snyder, Karen; Kim, Jinkoo; Gordon, James; Chetty, Indrin J; Wen, Ning

    2015-07-08

    This study details the generation, verification, and implementation of a treatment planning system (TPS) couch top model for patient support system used in conjunction with a dedicated stereotactic linear accelerator. Couch top model was created within the TPS using CT simulation images of the kVue Calpyso-compatible couchtop (with rails). Verification measurements were compared to TPS dose prediction for different energies (6 MV FFF and 10 MV FFF) and rail configurations (rails in and rails out) using: 1) central axis point-dose measurements with pinpoint chamber in water-equivalent phantom at 42 gantry angles for various field sizes (2 × 2 cm², 4 × 4 cm², 10 × 10 cm²); and 2) Gafchromic EBT3 film parallel to beam in acrylic slab to assess changes in surface and percent depth doses in PA geometry. To assess sensitivity of delivered dose to variations in patient lateral position, measurements at central axis using the pinpoint chamber geometry were taken at lateral couch displacements of 2, 5, and 10 mm for 6 MV FFF. The maximum percent difference for point-dose measurements was 3.24% (6 MV FFF) and 2.30% (10 MV FFF). The average percent difference for point-dose measurements was less than 1.10% for all beam energies and rail geometries. The maximum percent difference between calculated and measured dose can be as large as 13.0% if no couch model is used for dose calculation. The presence of the couch structures also impacts surface dose and PDD, which was evaluated with Gafchromic film measurements. The upstream shift in the depth of dose maximum (dmax) was found to be 10.5 mm for 6 MV FFF and 5.5 mm for 10 MV FFF for 'Rails In' configuration. Transmission of the treatment beam through the couch results in an increase in surface dose (absolute percentage) of approximately 50% for both photon energies (6 MV FFF and 10MV FFF). The largest sensitivity to lateral shifts occurred at the lateral boundary of the rail structures. The mean magnitude (standard

  19. Peripheral dose measurements with diode and thermoluminescence dosimeters for intensity modulated radiotherapy delivered with conventional and un-conventional linear accelerator.

    Science.gov (United States)

    Kinhikar, Rajesh; Gamre, Poonam; Tambe, Chandrashekhar; Kadam, Sudarshan; Biju, George; Suryaprakash; Magai, C S; Dhote, Dipak; Shrivastava, Shyam; Deshpande, Deepak

    2013-01-01

    The objective of this paper was to measure the peripheral dose (PD) with diode and thermoluminescence dosimeter (TLD) for intensity modulated radiotherapy (IMRT) with linear accelerator (conventional LINAC), and tomotherapy (novel LINAC). Ten patients each were selected from Trilogy dual-energy and from Hi-Art II tomotherapy. Two diodes were kept at 20 and 25 cm from treatment field edge. TLDs (LiF:MgTi) were also kept at same distance. TLDs were also kept at 5, 10, and 15 cm from field edge. The TLDs were read with REXON reader. The readings at the respective distance were recorded for both diode and TLD. The PD was estimated by taking the ratio of measured dose at the particular distance to the prescription dose. PD was then compared with diode and TLD for LINAC and tomotherapy. Mean PD for LINAC with TLD and diode was 2.52 cGy (SD 0.69), 2.07 cGy (SD 0.88) at 20 cm, respectively, while at 25 cm, it was 1.94 cGy (SD 0.58) and 1.5 cGy (SD 0.75), respectively. Mean PD for tomotherapy with TLD and diode was 1.681 cGy SD 0.53) and 1.58 (SD 0.44) at 20 cm, respectively. The PD was 1.24 cGy (SD 0.42) and 1.088 cGy (SD 0.35) at 25 cm, respectively, for tomotherapy. Overall, PD from tomotherapy was found lower than LINAC by the factor of 1.2-1.5. PD measurement is essential to find out the potential of secondary cancer. PD for both (conventional LINAC) and novel LINACs (tomotherapy) were measured and compared with each other. The comparison of the values for PD presented in this work and those published in the literature is difficult because of the different experimental conditions. The diode and TLD readings were reproducible and both the detector readings were comparable.

  20. SU-F-T-367: Using PRIMO, a PENELOPE-Based Software, to Improve the Small Field Dosimetry of Linear Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Benmakhlouf, H; Andreo, P [Department of Medical Physics, Karolinska University Hospital (Sweden); Brualla, L [NCTeam, Strahlenklinik, Universitatsklinikum Essen (Germany); Sempau, J [Institut de Tecniques Energetiques, Universitat Politecnica de Catalunya (Spain)

    2016-06-15

    Purpose: To calculate output correction factors for Varian Clinac 2100iX beams for seven small field detectors and use the values to determine the small field output factors for the linacs at Karolinska university hospital. Methods: Phase space files (psf) for square fields between 0.25cm and 10cm were calculated using the PENELOPE-based PRIMO software. The linac MC-model was tuned by comparing PRIMO-estimated and experimentally determined depth doses and lateral dose-profiles for 40cmx40cm fields. The calculated psf were used as radiation sources to calculate the correction factors of IBA and PTW detectors with the code penEasy/PENELOPE. Results: The optimal tuning parameters of the MClinac model in PRIMO were 5.4 MeV incident electron energy and zero energy spread, focal spot size and beam divergence. Correction factors obtained for the liquid ion chamber (PTW-T31018) are within 1% down to 0.5 cm fields. For unshielded diodes (IBA-EFD, IBA-SFD, PTW-T60017 and PTW-T60018) the corrections are up to 2% at intermediate fields (>1cm side), becoming down to −11% for fields smaller than 1cm. The shielded diode (IBA-PFD and PTW-T60016) corrections vary with field size from 0 to −4%. Volume averaging effects are found for most detectors in the presence of 0.25cm fields. Conclusion: Good agreement was found between correction factors based on PRIMO-generated psf and those from other publications. The calculated factors will be implemented in output factor measurements (using several detectors) in the clinic. PRIMO is a userfriendly general code capable of generating small field psf and can be used without having to code own linac geometries. It can therefore be used to improve the clinical dosimetry, especially in the commissioning of linear accelerators. Important dosimetry data, such as dose-profiles and output factors can be determined more accurately for a specific machine, geometry and setup by using PRIMO and having a MC-model of the detector used.

  1. A Monte Carlo investigation of low-Z target image quality generated in a linear accelerator using Varian's VirtuaLinac

    Energy Technology Data Exchange (ETDEWEB)

    Parsons, David, E-mail: david.parsons@dal.ca [Department of Physics and Atmospheric Science, Dalhousie University, 5820 University Avenue, Halifax, Nova Scotia B3H 1V7 (Canada); Robar, James L., E-mail: james.robar@cdha.nshealth.ca [Department of Radiation Oncology and Department of Physics and Atmospheric Science, Dalhousie University, 5820 University Avenue, Halifax, Nova Scotia B3H 1V7 (Canada); Sawkey, Daren, E-mail: daren.sawkey@varian.com [Varian Medical Systems, Inc., 3120 Hansen Way, Palo Alto, California 94304 (United States)

    2014-02-15

    Purpose: The focus of this work was the demonstration and validation of VirtuaLinac with clinical photon beams and to investigate the implementation of low-Z targets in a TrueBeam linear accelerator (Linac) using Monte Carlo modeling. Methods: VirtuaLinac, a cloud based web application utilizing Geant4 Monte Carlo code, was used to model the Linac treatment head components. Particles were propagated through the lower portion of the treatment head using BEAMnrc. Dose distributions and spectral distributions were calculated using DOSXYZnrc and BEAMdp, respectively. For validation, 6 MV flattened and flattening filter free (FFF) photon beams were generated and compared to measurement for square fields, 10 and 40 cm wide and at d{sub max} for diagonal profiles. Two low-Z targets were investigated: a 2.35 MeV carbon target and the proposed 2.50 MeV commercial imaging target for the TrueBeam platform. A 2.35 MeV carbon target was also simulated in a 2100EX Clinac using BEAMnrc. Contrast simulations were made by scoring the dose in the phosphor layer of an IDU20 aSi detector after propagating through a 4 or 20 cm thick phantom composed of water and ICRP bone. Results: Measured and modeled depth dose curves for 6 MV flattened and FFF beams agree within 1% for 98.3% of points at depths greater than 0.85 cm. Ninety three percent or greater of points analyzed for the diagonal profiles had a gamma value less than one for the criteria of 1.5 mm and 1.5%. The two low-Z target photon spectra produced in TrueBeam are harder than that from the carbon target in the Clinac. Percent dose at depth 10 cm is greater by 3.6% and 8.9%; the fraction of photons in the diagnostic energy range (25–150 keV) is lower by 10% and 28%; and contrasts are lower by factors of 1.1 and 1.4 (4 cm thick phantom) and 1.03 and 1.4 (20 cm thick phantom), for the TrueBeam 2.35 MV/carbon and commercial imaging beams, respectively. Conclusions: VirtuaLinac is a promising new tool for Monte Carlo modeling of

  2. Neutron activation processes in the medical linear accelerator Elekta Precise; Procesos de activacion neutronica en el acelerador lineal medico Elekta Precise

    Energy Technology Data Exchange (ETDEWEB)

    Juste, B.; Miro, R.; Verdu, G.; Diez, S.; Campayo, J. M.

    2014-07-01

    In radiotherapy beams of high energy photons produced lower doses in the skin and a lower dose dispersed into surrounding healthy tissue. However, when operating above 10 MV, Linacs have some drawbacks such as the generation of photo-neutrons and activation of some components of the accelerator. The launch and capture of neutrons produce radioactive nuclei that can radiate even when the accelerator is not working. These reactions occur mainly in the heavier materials of the head accelerator. This work has studied the activation generated isotopes resulting, concluding that these derived doses are not negligible. (Author)

  3. Dielectric-wall linear accelerator with a high voltage fast rise time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators

    Science.gov (United States)

    Caporaso, George J.; Sampayan, Stephen E.; Kirbie, Hugh C.

    1998-01-01

    A dielectric-wall linear accelerator is improved by a high-voltage, fast rise-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface.

  4. Biokinetic characterization of the acceleration phase in autotrophic ammonia oxidation.

    Science.gov (United States)

    Chandran, Kartik; Smets, Barth F

    2008-08-01

    Batch autotrophic ammonia oxidation tracked through oxygen uptake measurements displays a preliminary acceleration phase. Failure to recognize the acceleration phase and fitting batch ammonia oxidation profiles with standard Monod-type mathematical models can result in meaningless kinetic parameter estimates. The objectives of this study were to examine the factors controlling the acceleration phase and to derive and test empirical and metabolic models for its description. Because of possible sustained reducing power limitation during batch ammonia oxidation, the extent of the acceleration phase (1) increased with increasing initial ammonia concentration, (2) did not systematically vary with initial biomass concentrations, and (3) increased in response to starvation. Concurrent hydroxylamine oxidation significantly reduced the acceleration phase potentially by relieving reducing power limitation. A nonlinear empirical model described the acceleration phase more accurately than a linear empirical model. The metabolic model also captured experimental trends exceedingly well, but required determination of additional parameters and variables.

  5. Determination of the neutron spectra in the treatment room of a linear accelerator for radiotherapy; Determinacion de los espectros de neutrones en la sala de tratamiento de un acelerador lineal para radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H.R. [Universidad Autonoma de Zacatecas, Cuerpo Academico de Radiobiologia, A.P. 336, 98000 Zacatecas (Mexico); Barquero, R. [Hospital Universitario Rio Hortega, Valladolid (Spain); Mendez, R.; Iniguez, M.P. [Depto. de Fisica Teorica, Atomica, Molecular y Nuclear, Universidad de Valladolid, 47011 Valladolid (Spain)

    2003-07-01

    By means of a series of measures and Monte Carlo calculations the dosimetric characteristics of the photoneutrons have been determined that take place in volume to a linear accelerator of radiotherapy of 18 MV, LINAC, mark Siemens Mevatron model. The measures were carried out with thermoluminescent dosemeters TLD 600 and TLD 700 that were naked exposed and confined with cover of Cd and Sn, inside a sphere of paraffin and inside spheres Bonner. (Author)

  6. 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.

  7. Dosimetry of the stereotactic radiosurgery with linear accelerators equipped with micro multi-blades collimators; Dosimetria dos sistemas de radiocirurgia estereotaxica com aceleradores lineares equipados com colimadores micro multi-laminas

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Andre Mozart de Miranda

    2008-07-01

    In this work, absorbed dose to water produced by the radiation beam of a clinical linear accelerator - CLINAC 600C{sup TM} (Varian), with a photon beam of 6 MV, were evaluated both theoretically and experimentally. This determination includes square and circular field configurations, the last one obtained with a micro multi leaf collimator - mMLC m3{sup TM} (Brain Lab). Theoretical evaluation was performed throughout Monte Carlo method. Experimental measurements of Percentage Depth Dose - PDD and derived Tissue Maximum Ratio - TMR curves from CLINAC 600C were validated by comparison with reference values as well as with measurements using different detectors. The results indicate local differences smaller than 5% and average differences smaller than 1,5% for each evaluated field, if they are compared to the previous commissioning values (made in 1999) and to the values of literature. Comparisons of ionization chamber and diode result in an average local difference of -0,6% for PDD measurements, and within 1% for lateral dose profiles, at depth, in the flat region. Diode provides measurements with better spatial resolution. Current output factors of open fields agree with reference values within 1,03% of discrepancy level. Current absorbed dose distributions in water are, now, considered reference values and allow characterization of this CLINAC for patient dose calculation. The photon spectra resulting from simulations with PENELOPE and MCNP codes agree approximately in 80% of the sampled points, in what average energies of (1,6 {+-} 0,3)MeV, with MCNP, and of (1,72 {+-} 0,08)MeV, with PENELOPE, are coincident. The created simple source model of the CLINAC 600C, using the PENELOPE code, allows one to calculate dose distributions in water, for open fields, with discrepancies of the order of {+-} 1,0% in dose and of {+-} 0,1 cm in position, if they are compared to experimental measurements. These values met the initial proposed criteria to validate the simulation

  8. Plasma-based accelerator structures

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Carl B. [Univ. of California, Berkeley, CA (United States)

    1999-12-01

    Plasma-based accelerators have the ability to sustain extremely large accelerating gradients, with possible high-energy physics applications. This dissertation further develops the theory of plasma-based accelerators by addressing three topics: the performance of a hollow plasma channel as an accelerating structure, the generation of ultrashort electron bunches, and the propagation of laser pulses is underdense plasmas.

  9. 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

  10. An intuitionistic fuzzy multi-objective non-linear programming model for sustainable irrigation water allocation under the combination of dry and wet conditions

    Science.gov (United States)

    Li, Mo; Fu, Qiang; Singh, Vijay P.; Ma, Mingwei; Liu, Xiao

    2017-12-01

    Water scarcity causes conflicts among natural resources, society and economy and reinforces the need for optimal allocation of irrigation water resources in a sustainable way. Uncertainties caused by natural conditions and human activities make optimal allocation more complex. An intuitionistic fuzzy multi-objective non-linear programming (IFMONLP) model for irrigation water allocation under the combination of dry and wet conditions is developed to help decision makers mitigate water scarcity. The model is capable of quantitatively solving multiple problems including crop yield increase, blue water saving, and water supply cost reduction to obtain a balanced water allocation scheme using a multi-objective non-linear programming technique. Moreover, it can deal with uncertainty as well as hesitation based on the introduction of intuitionistic fuzzy numbers. Consideration of the combination of dry and wet conditions for water availability and precipitation makes it possible to gain insights into the various irrigation water allocations, and joint probabilities based on copula functions provide decision makers an average standard for irrigation. A case study on optimally allocating both surface water and groundwater to different growth periods of rice in different subareas in Heping irrigation area, Qing'an County, northeast China shows the potential and applicability of the developed model. Results show that the crop yield increase target especially in tillering and elongation stages is a prevailing concern when more water is available, and trading schemes can mitigate water supply cost and save water with an increased grain output. Results also reveal that the water allocation schemes are sensitive to the variation of water availability and precipitation with uncertain characteristics. The IFMONLP model is applicable for most irrigation areas with limited water supplies to determine irrigation water strategies under a fuzzy environment.

  11. 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)

  12. A study of the effect of in-line and perpendicular magnetic fields on beam characteristics of electron guns in medical linear accelerators.

    Science.gov (United States)

    Constantin, Dragoş E; Fahrig, Rebecca; Keall, Paul J

    2011-07-01

    Using magnetic resonance imaging (MRI) for real-time guidance during radiotherapy is an active area of research and development. One aspect of the problem is the influence of the MRI scanner, modeled here as an external magnetic field, on the medical linear accelerator (linac) components. The present work characterizes the behavior of two medical linac electron guns with external magnetic fields for in-line and perpendicular orientations of the linac with respect to the MRI scanner. Two electron guns, Litton L-2087 and Varian VTC6364, are considered as representative models for this study. Emphasis was placed on the in-line design approach in which case the MRI scanner and the linac axes of symmetry coincide and assumes no magnetic shielding of the linac. For the in-line case, the magnetic field from a 0.5 T open MRI (GE Signa SP) magnet with a 60 cm gap between its poles was computed and used in full three dimensional (3D) space charge simulations, whereas for the perpendicular case the magnetic field was constant. For the in-line configuration, it is shown that the electron beam is not deflected from the axis of symmetry of the gun and the primary beam current does not vanish even at very high values of the magnetic field, e.g., 0.16 T. As the field strength increases, the primary beam current has an initial plateau of constant value after which its value decreases to a minimum corresponding to a field strength of approximately 0.06 T. After the minimum is reached, the current starts to increase slowly. For the case when the beam current computation is performed at the beam waist position the initial plateau ends at 0.016 T for Litton L-2087 and at 0.012 T for Varian VTC6364. The minimum value of the primary beam current is 27.5% of the initial value for Litton L-2087 and 22.9% of the initial value for Varian VTC6364. The minimum current is reached at 0.06 and 0.062 T for Litton L-2087 and Varian VTC6364, respectively. At 0.16 T the beam current increases to 40

  13. VERIFIKASI PERCENTAGE DEPTH DOSE (PDD) DAN PROFILE DOSE PESAWAT LINEAR ACCELERATOR (LINAC) BERKAS ELEKTRON 6 MeV, 9 MeV, 12 MeV DAN 15 MeV MENGGUNAKAN WATER PHANTOM

    OpenAIRE

    Marten Padang, Jumedi

    2015-01-01

    Abstrak Telah dilakukan penelitian tentang Verifikasi Percentage Depth Dose (PDD) dan Profile Dose Pesawat Linear Accelerator (LINAC) Berkas Elektron 6 MeV, 9 MeV, 12 MeV dan 15 MeV Menggunakan Water Phantom. Penelitian ini bertujuan untuk menganalisis Percentage Depth Dose (PDD) dan Profile Dose pesawat linac jenis HCX 5640 berkas elektron 6 MeV, 9 MeV, 12 MeV dan 15 MeV untuk luas lapangan 10 x 10 cm2. Penelitian ini membandingkan data acuan yang telah ada sebelumnya dan data yang dipero...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  15. High Energy Particle Accelerators

    CERN Multimedia

    Audio Productions, Inc, New York

    1960-01-01

    Film about the different particle accelerators in the US. Nuclear research in the US has developed into a broad and well-balanced program.Tour of accelerator installations, accelerator development work now in progress and a number of typical experiments with high energy particles. Brookhaven, Cosmotron. Univ. Calif. Berkeley, Bevatron. Anti-proton experiment. Negative k meson experiment. Bubble chambers. A section on an electron accelerator. Projection of new accelerators. Princeton/Penn. build proton synchrotron. Argonne National Lab. Brookhaven, PS construction. Cambridge Electron Accelerator; Harvard/MIT. SLAC studying a linear accelerator. Other research at Madison, Wisconsin, Fixed Field Alternate Gradient Focusing. (FFAG) Oakridge, Tenn., cyclotron. Two-beam machine. Comments : Interesting overview of high energy particle accelerators installations in the US in these early years. .

  16. Optimal Cropping Pattern Based on Multiple Economic, Regional, and Agricultural Sustainability Criteria in Sari, Iran: Application of a Consolidated Model of AHP and Linear Programming

    Directory of Open Access Journals (Sweden)

    E. Fallahi

    2016-10-01

    Full Text Available Introduction: Determining a suitable cropping pattern is an important task for planners and requires an exact and realistic decision-making process based on several goals and criteria corresponding to secure the interest of agricultural beneficiaries in long-term. Accordingly, this study reviews the current pattern operated by farmers in Sari, Iran, and intends to provide a cropping pattern that considers the multifold regional and agricultural sustainability criteria along with economic considerations. Materials and Methods: In order to achieve the study goals, a consolidated model of AHP and Linear Programming was applied. For this purpose, we constructed a three-level AHP, including a goal (determining the weight of each crop, seven criteria, and seven alternatives. Profitability, compatibility with regional and geographical conditions, water consumption, environmental effects of cropping, job creation opportunities, skill and proficiency required for producing a crop, and risk taken to cultivate a crop were considered as the criteria in the model. Seven alternative crops including rice, wheat, rapeseed, barley, soybean, clover, and vegetables were considered too. The next step is determining the weight of each criterion with regard to the goal and the weight of each alternative with regard to each criteria. By multiplying these weights, final weights for various crops were obtained from the model. Derived weights for each crop were then applied as objective function coefficients in the Linear Programming model and the model was solved subject to the constraints. Results and Discussion: Optimal cropping pattern determined based on the consolidated model of AHP and Linear Programming and the results compared to a scenario that only looks forward to maximizing the economic interests. Due to the low profitability of rapeseed and barley, these crops eliminated from the pattern in the profit-maximizing scenario. According to the results, the

  17. Neutron activation processes in the medical linear accelerator Elekta Precise; Procesos de activacion neutronica en el acelerador lineal medico Elekta Precise

    Energy Technology Data Exchange (ETDEWEB)

    Juste, B.; Miro, R.; Verdu, G.; Diez, S.; Campayo, J. M.

    2015-07-01

    Monte Carlo estimation of the giant-dipole-resonance (GRN) photoneutrons insider the Elekta Precise Linac head (emitting a 15 MV photon beam) were performed using the MCNP6 code. Each component of Linac head geometry and materials were modelled in detail using the given manufacturer information. Primary photons generate photoneutrons and its transport across the treatment head was simulated, including the (n, γ) reactions which undergo activation products. The MCNP6 was used to develop a method for quantifying the activation of accelerator components. The approach described in this paper is useful in quantifying the origin and the amount of nuclear activation. (Author)

  18. Preliminary experience in treatment of papillary and macular retinoblastoma: evaluation of local control and local complications after treatment with linear accelerator-based stereotactic radiotherapy with micromultileaf collimator as second-line or salvage treatment after chemotherapy.

    Science.gov (United States)

    Pica, Alessia; Moeckli, Raphael; Balmer, Aubin; Beck-Popovic, Maja; Chollet-Rivier, Madeleine; Do, Huu-Phuoc; Weber, Damien C; Munier, Francis L

    2011-12-01

    To determine the local control and complication rates for children with papillary and/or macular retinoblastoma progressing after chemotherapy and undergoing stereotactic radiotherapy (SRT) with a micromultileaf collimator. Between 2004 and 2008, 11 children (15 eyes) with macular and/or papillary retinoblastoma were treated with SRT. The mean age was 19 months (range, 2-111). Of the 15 eyes, 7, 6, and 2 were classified as International Classification of Intraocular Retinoblastoma Group B, C, and E, respectively. The delivered dose of SRT was 50.4 Gy in 28 fractions using a dedicated micromultileaf collimator linear accelerator. The median follow-up was 20 months (range, 13-39). Local control was achieved in 13 eyes (87%). The actuarial 1- and 2-year local control rates were both 82%. SRT was well tolerated. Late adverse events were reported in 4 patients. Of the 4 patients, 2 had developed focal microangiopathy 20 months after SRT; 1 had developed a transient recurrence of retinal detachment; and 1 had developed bilateral cataracts. No optic neuropathy was observed. Linear accelerator-based SRT for papillary and/or macular retinoblastoma in children resulted in excellent tumor control rates with acceptable toxicity. Additional research regarding SRT and its intrinsic organ-at-risk sparing capability is justified in the framework of prospective trials. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Preliminary Experience in Treatment of Papillary and Macular Retinoblastoma: Evaluation of Local Control and Local Complications After Treatment With Linear Accelerator-Based Stereotactic Radiotherapy With Micromultileaf Collimator as Second-Line or Salvage Treatment After Chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Pica, Alessia, E-mail: Alessia.Pica@chuv.ch [Department of Radiation Oncology, Centre Hospitalier Universitaire Vaudois, Lausanne (Switzerland); Moeckli, Raphael [University Institute for Radiation Physics, Centre Hospitalier Universitaire Vaudois, Lausanne (Switzerland); Balmer, Aubin [Department of Radiation Oncology, Jules Gonin Eye Hospital, Lausanne (Switzerland); Beck-Popovic, Maja [Unit of Pediatric Oncology, University of Lausanne, Lausanne (Switzerland); Chollet-Rivier, Madeleine [Department of Anesthesiology, University of Lausanne, Lausanne (Switzerland); Do, Huu-Phuoc [University Institute for Radiation Physics, Centre Hospitalier Universitaire Vaudois, Lausanne (Switzerland); Weber, Damien C. [Department of Radiation Oncology, Geneva University Hospital, University of Geneva, Geneva (Switzerland); Munier, Francis L. [Department of Radiation Oncology, Jules Gonin Eye Hospital, Lausanne (Switzerland)

    2011-12-01

    Purpose: To determine the local control and complication rates for children with papillary and/or macular retinoblastoma progressing after chemotherapy and undergoing stereotactic radiotherapy (SRT) with a micromultileaf collimator. Methods and Materials: Between 2004 and 2008, 11 children (15 eyes) with macular and/or papillary retinoblastoma were treated with SRT. The mean age was 19 months (range, 2-111). Of the 15 eyes, 7, 6, and 2 were classified as International Classification of Intraocular Retinoblastoma Group B, C, and E, respectively. The delivered dose of SRT was 50.4 Gy in 28 fractions using a dedicated micromultileaf collimator linear accelerator. Results: The median follow-up was 20 months (range, 13-39). Local control was achieved in 13 eyes (87%). The actuarial 1- and 2-year local control rates were both 82%. SRT was well tolerated. Late adverse events were reported in 4 patients. Of the 4 patients, 2 had developed focal microangiopathy 20 months after SRT; 1 had developed a transient recurrence of retinal detachment; and 1 had developed bilateral cataracts. No optic neuropathy was observed. Conclusions: Linear accelerator-based SRT for papillary and/or macular retinoblastoma in children resulted in excellent tumor control rates with acceptable toxicity. Additional research regarding SRT and its intrinsic organ-at-risk sparing capability is justified in the framework of prospective trials.

  20. Diagnostics for advanced laser acceleration experiments

    Energy Technology Data Exchange (ETDEWEB)

    Misuri, Alessio [Univ. of Pisa (Italy)

    2002-01-01

    The first proposal for plasma based accelerators was suggested by 1979 by Tajima and Dawson. Since then there has been a tremendous progress both theoretically and experimentally. The theoretical progress is particularly due to the growing interest in the subject and to the development of more accurate numerical codes for the plasma simulations (especially particle-in-cell codes). The experimental progress follows from the development of multi-terawatt laser systems based on the chirped-pulse amplification technique. These efforts have produced results in several experiments world-wide, with the detection of accelerated electrons of tens of MeV. The peculiarity of these advanced accelerators is their ability to sustain extremely large acceleration gradients. In the conventional radio frequency linear accelerators (RF linacs) the acceleration gradients are limited roughly to 100 MV/m; this is partially due to breakdown which occurs on the walls of the structure. The electrical breakdown is originated by the emission of the electrons from the walls of the cavity. The electrons cause an avalanche breakdown when they reach other metal parts of the RF linacs structure.

  1. Beam Diagnostics for Accelerators

    CERN Document Server

    Koziol, Heribert

    2005-01-01

    This introductory course aims at a reasonably complete coverage of beam diagnostic devices used in linear and circular accelerators and in primary beam lines. The weight is on the concepts and the indication of variants, while for technical details the reader is referred to the literature. The present updated version replaces those from previous General Accelerator Physics Courses.

  2. TU-F-CAMPUS-T-04: An Evaluation of Out-Of-Field Doses for Electron Beams From Modern Varian and Elekta Linear Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Cardenas, C; Nitsch, P; Kudchadker, R; Howell, R; Kry, S [UT MD Anderson Cancer Center, Houston, TX (United States)

    2015-06-15

    Purpose: Accurately determining out-of-field doses when using electron beam radiotherapy is of importance when treating pregnant patients or patients with implanted electronic devices. Scattered doses outside of the applicator field in electron beams have not been broadly investigated, especially since manufacturers have taken different approaches in applicator designs. Methods: In this study, doses outside of the applicator field were measured for electron beams produced by a 10×10 applicator on two Varian 21iXs operating at 6, 9, 12, 16, and 20 MeV, a Varian TrueBeam operating at 6, 9, 12, 16, and 20 MeV, and an Elekta Versa HD operating at 6, 9, 12 and 15 MeV. Peripheral dose profiles and percent depth doses were measured in a Wellhofer water phantom at 100 cm SSD with a Farmer ion chamber. Doses were compared to peripheral photon doses from AAPM’s Task Group #36 report. Results: Doses were highest for the highest electron energies. Doses typically decreased with increasing distance from the field edge but showed substantial increases over some distance ranges. Substantial dose differences were observed between different accelerators; the Elekta accelerator had much higher doses than any Varian unit examined. Surprisingly, doses were often similar to, and could be much higher than, doses from photon therapy. 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. Conclusion: The results of this study indicate that proper shielding may be very important when utilizing electron beams, particularly on a Versa HD, while treating pregnant patients or those with implanted electronic devices. Applying a water equivalent bolus of Emax(MeV)/4 thickness (cm) on the patient would reduce fetal dose drastically for all clinical energies and is a practical solution to manage the potentially high peripheral doses seen from modern electron beams. Funding from NIH Grant number: #CA180803.

  3. Highly Accelerated, Intravascular T1, T2, and Proton Density Mapping with Linear Algebraic Modeling and Sensitivity Profile Correction at 3T.

    Science.gov (United States)

    Wang, Guan; Zhang, Yi; Hegde, Shashank Sathyanarayana; Bottomley, Paul A

    2016-05-01

    Vessel wall MRI with intravascular (IV) detectors can produce superior local signal-to-noise ratios (SNR) and generate high-resolution T1, T2, and proton density (PD) maps that could be used to automatically classify atherosclerotic lesion stage. However, long acquisition times potentially limit multi-parametric mapping. Here, for the first time, spectroscopy with linear algebraic modeling (SLAM) is applied to yield accurate compartment-average T1, T2 and PD measures at least 10 times faster compared to a standard full k-space reconstructed MIX-TSE sequence at 3T. Simple phase and magnitude sensitivity corrections are incorporated into the SLAM reconstruction to compensate for IV detector non-uniformity.

  4. Multidimensional Plasma Wake Excitation in the Non-linear Blowout Regime

    CERN Document Server

    Vieira, J.; Silva, L.O.

    2016-01-01

    Plasma accelerators can sustain very high acceleration gradients. They are promising candidates for future generations of particle accelerators for sev- eral scientific, medical and technological applications. Current plasma based acceleration experiments operate in the relativistic regime, where the plasma response is strongly non-linear. We outline some of the key properties of wake- field excitation in these regimes. We outline a multidimensional theory for the excitation of plasma wakefields in connection with current experiments. We then use these results and provide design guidelines for the choice of laser and plasma parameters ensuring a stable laser wakefield accelerator that maximizes the quality of the accelerated electrons. We also mention some of the future challenges associated with this technology.

  5. Laser Wakefield Accelerators

    OpenAIRE

    Najmudin, Z.

    2017-01-01

    The one-dimensional wakefield generation equations are solved for increasing levels of non-linearity, to demonstrate how they contribute to the overall behaviour of a non-linear wakefield in a plasma. The effect of laser guiding is also studied as a way to increase the interaction length of a laser wakefield accelerator.

  6. Comparative study of the parameters associated with quality control and absorbed dose in linear accelerators with (FF) and without (FFF) flattening filter; Estudo comparativo dos parametros associados a dose absorvida e controle de qualidade em aceleradores lineares com filtro aplainador (FF) e sem filtro aplainador (FFF)

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Anderson Sorgatti de

    2017-11-01

    Teletherapy, radiation therapy with linear accelerators, for cancer treatment has being used for years with good clinical results.Since the 90's the removal of the flattening filter, item placed at the gantry of the machine, has shown better results for the treatment of some cancers thus being extensively studied. Treatments with Intensity Modulated Radiotherapy (IMRT) and Stereotaxic Radiotherapy (SRT) were more efficient without the flattening filter. Varian Oncology released the TrueBeam in 2012, a accelerator capable of operating with or without the flattening filter. The aim of this work is to access homogeneity of the percentage depth dose (PDP) and beam quality index (TPR20/10), two important parameters used in patient dose calculations. The data used for analysis were obtained with the Israelita Albert Einstein Hospital (HIAE), Real Portugues Hospital (RHP) and 3 more institutions located in the United States. The statistical data analysis allowed to observe the parameters behaviors. In general, they were very homogeneous, with errors smaller than 1% confirming the conformance of the TrueBeam accelerators. (author)

  7. A virtual photon source model of an Elekta linear accelerator with integrated mini MLC for Monte Carlo based IMRT dose calculation.

    Science.gov (United States)

    Sikora, M; Dohm, O; Alber, M

    2007-08-07

    A dedicated, efficient Monte Carlo (MC) accelerator head model for intensity modulated stereotactic radiosurgery treatment planning is needed to afford a highly accurate simulation of tiny IMRT fields. A virtual source model (VSM) of a mini multi-leaf collimator (MLC) (the Elekta Beam Modulator (EBM)) is presented, allowing efficient generation of particles even for small fields. The VSM of the EBM is based on a previously published virtual photon energy fluence model (VEF) (Fippel et al 2003 Med. Phys. 30 301) commissioned with large field measurements in air and in water. The original commissioning procedure of the VEF, based on large field measurements only, leads to inaccuracies for small fields. In order to improve the VSM, it was necessary to change the VEF model by developing (1) a method to determine the primary photon source diameter, relevant for output factor calculations, (2) a model of the influence of the flattening filter on the secondary photon spectrum and (3) a more realistic primary photon spectrum. The VSM model is used to generate the source phase space data above the mini-MLC. Later the particles are transmitted through the mini-MLC by a passive filter function which significantly speeds up the time of generation of the phase space data after the mini-MLC, used for calculation of the dose distribution in the patient. The improved VSM model was commissioned for 6 and 15 MV beams. The results of MC simulation are in very good agreement with measurements. Less than 2% of local difference between the MC simulation and the diamond detector measurement of the output factors in water was achieved. The X, Y and Z profiles measured in water with an ion chamber (V = 0.125 cm(3)) and a diamond detector were used to validate the models. An overall agreement of 2%/2 mm for high dose regions and 3%/2 mm in low dose regions between measurement and MC simulation for field sizes from 0.8 x 0.8 cm(2) to 16 x 21 cm(2) was achieved. An IMRT plan film verification

  8. Monte Carlo modeling of HD120 multileaf collimator on Varian TrueBeam linear accelerator for verification of 6X and 6X FFF VMAT SABR treatment plans.

    Science.gov (United States)

    Bergman, Alanah M; Gete, Ermias; Duzenli, Cheryl; Teke, Tony

    2014-05-08

    A Monte Carlo (MC) validation of the vendor-supplied Varian TrueBeam 6 MV flattened (6X) phase-space file and the first implementation of the Siebers-Keall MC MLC model as applied to the HD120 MLC (for 6X flat and 6X flattening filter-free (6X FFF) beams) are described. The MC model is validated in the context of VMAT patient-specific quality assurance. The Monte Carlo commissioning process involves: 1) validating the calculated open-field percentage depth doses (PDDs), profiles, and output factors (OF), 2) adapting the Siebers-Keall MLC model to match the new HD120-MLC geometry and material composition, 3) determining the absolute dose conversion factor for the MC calculation, and 4) validating this entire linac/MLC in the context of dose calculation verification for clinical VMAT plans. MC PDDs for the 6X beams agree with the measured data to within 2.0% for field sizes ranging from 2 × 2 to 40 × 40 cm2. Measured and MC profiles show agreement in the 50% field width and the 80%-20% penumbra region to within 1.3 mm for all square field sizes. MC OFs for the 2 to 40 cm2 square fields agree with measurement to within 1.6%. Verification of VMAT SABR lung, liver, and vertebra plans demonstrate that measured and MC ion chamber doses agree within 0.6% for the 6X beam and within 2.0% for the 6X FFF beam. A 3D gamma factor analysis demonstrates that for the 6X beam, > 99% of voxels meet the pass criteria (3%/3 mm). For the 6X FFF beam, > 94% of voxels meet this criteria. The TrueBeam accelerator delivering 6X and 6X FFF beams with the HD120 MLC can be modeled in Monte Carlo to provide an independent 3D dose calculation for clinical VMAT plans. This quality assurance tool has been used clinically to verify over 140 6X and 16 6X FFF TrueBeam treatment plans.

  9. Definition of a reference metrology network for the positioning of a large linear accelerator; Definition d'un reseau de reference metrologique pour le positionnement d'un grand accelerateur lineaire

    Energy Technology Data Exchange (ETDEWEB)

    Becker, F

    2003-12-15

    This thesis is a study of the Compact Linear Collider (CLIC) alignment system, a project of linear accelerator of about 30 km long of the European Organization for Nuclear Research (CERN). The pre-alignment tolerance on the transverse positions of the components of the CLIC linacs is typically ten microns over distances of 200 m. This research is a consequence of 10 years work, where several sets of special sensors dedicated to metrology have been adapted for the CLIC project. Most of these sensors deliver measurements linked to geometric references sensitive to gravity fluctuation. An important part of this work is therefore dedicated to study the gravity disruptions as a high level of accuracy is required. The parameters to take into account in the use of the hydrostatic leveling have thus been highlighted. A proposal of configuration of the system alignment based on a selection of sensors has also been given in this research. Computer models of different possible configurations have been presented. As the existing computing software was inappropriate, a new object oriented software package has been developed, to ensure future upgrades. An optimized configuration of the network has been defined from a set of simulations. Finally, due to problems in the use of hydrostatic leveling systems, a solution based on the use of a long laser beam as an alternative solution is discussed. (author)

  10. High Gradient Accelerator Research

    Energy Technology Data Exchange (ETDEWEB)

    Temkin, Richard [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Physics. Plasma Science and Fusion Center

    2016-07-12

    The goal of the MIT program of research on high gradient acceleration is the development of advanced acceleration concepts that lead to a practical and affordable next generation linear collider at the TeV energy level. Other applications, which are more near-term, include accelerators for materials processing; medicine; defense; mining; security; and inspection. The specific goals of the MIT program are: • Pioneering theoretical research on advanced structures for high gradient acceleration, including photonic structures and metamaterial structures; evaluation of the wakefields in these advanced structures • Experimental research to demonstrate the properties of advanced structures both in low-power microwave cold test and high-power, high-gradient test at megawatt power levels • Experimental research on microwave breakdown at high gradient including studies of breakdown phenomena induced by RF electric fields and RF magnetic fields; development of new diagnostics of the breakdown process • Theoretical research on the physics and engineering features of RF vacuum breakdown • Maintaining and improving the Haimson / MIT 17 GHz accelerator, the highest frequency operational accelerator in the world, a unique facility for accelerator research • Providing the Haimson / MIT 17 GHz accelerator facility as a facility for outside users • Active participation in the US DOE program of High Gradient Collaboration, including joint work with SLAC and with Los Alamos National Laboratory; participation of MIT students in research at the national laboratories • Training the next generation of Ph. D. students in the field of accelerator physics.

  11. TECHNIQUE OF ESTIMATION OF ERROR IN THE REFERENCE VALUE OF THE DOSE DURING THE LINEAR ACCELERATOR RADIATION OUTPUT CALIBRATION PROCEDURE. Part 2. Dependence on the characteristics of collimator, optical sourse-distance indicator, treatment field, lasers and treatment couch

    Directory of Open Access Journals (Sweden)

    Y. V. Tsitovich

    2016-01-01

    Full Text Available To ensure the safety of radiation oncology patients needed to provide consistent functional characteristics of the medical linear accelerators, which affect the accuracy of dose delivery. To this end, their quality control procedures, which include the calibration of radiation output of the linac, the error in determining the dose reference value during which must not exceed 2 %, is provided. The aim is to develop a methodology for determining the error (difference between a measured value of quantity and its true value in determining this value, depending on the characteristics of the collimator, the source to surface distance pointer, lasers, radiation field and treatment table. To achieve the objectives have been carried out dosimetric measurements of Trilogy S/N 3567 linac dose distributions, on the basis of which dose errors depending on the accuracy setting the zero position of the collimator, the deviation of the collimator rotation isocenter, the sourcesurface distance pointer accuracy, field size accuracy, the accuracy of lasers and treatment table positioning were obtained. It was found that the greatest impact on the value of the error has the error in the optical SSD indication and the error in the lasers position in the plane perpendicular to the plane of incidence of the radiation beam (up to 3.64 % for the energy of 6 MV. Dose errors caused by error in the field size were different for two photon energies, and reached 2.54 % for 6 MeV and 1.33% for 18 MeV. Errors caused by the rest of the characteristic do not exceed 1 %. Thus, it is possible to express the results of periodic quality control of these devices integrated in linac in terms of dose and use them to conduct a comprehensive assessment of the possibility of clinical use of a linear accelerator for oncology patients irradiation on the basis of the calibration of radiation output in case of development of techniques that allow to analyze the influence dosimetric

  12. Small fields output factors measurements and correction factors determination for several detectors for a CyberKnife® and linear accelerators equipped with microMLC and circular cones.

    Science.gov (United States)

    Bassinet, C; Huet, C; Derreumaux, S; Brunet, G; Chéa, M; Baumann, M; Lacornerie, T; Gaudaire-Josset, S; Trompier, F; Roch, P; Boisserie, G; Clairand, I

    2013-07-01

    The use of small photon fields is now an established practice in stereotactic radiosurgery and radiotherapy. However, due to a lack of lateral electron equilibrium and high dose gradients, it is difficult to accurately measure the dosimetric quantities required for the commissioning of such systems. Moreover, there is still no metrological dosimetric reference for this kind of beam today. In this context, the first objective of this work was to determine and to compare small fields output factors (OF) measured with different types of active detectors and passive dosimeters for three types of facilities: a CyberKnife(®) system, a dedicated medical linear accelerator (Novalis) equipped with m3 microMLC and circular cones, and an adaptive medical linear accelerator (Clinac 2100) equipped with an additional m3 microMLC. The second one was to determine the kQclin,Qmsr (fclin,fmsr) correction factors introduced in a recently proposed small field dosimetry formalism for different active detectors. Small field sizes were defined either by microMLC down to 6 × 6 mm(2) or by circular cones down to 4 mm in diameter. OF measurements were performed with several commercially available active detectors dedicated to measurements in small fields (high resolution diodes: IBA SFD, Sun Nuclear EDGE, PTW 60016, PTW 60017; ionizing chambers: PTW 31014 PinPoint chamber, PTW 31018 microLion liquid chamber, and PTW 60003 natural diamond). Two types of passive dosimeters were used: LiF microcubes and EBT2 radiochromic films. Significant differences between the results obtained by several dosimetric systems were observed, particularly for the smallest field size for which the difference in the measured OF reaches more than 20%. For passive dosimeters, an excellent agreement was observed (better than 2%) between EBT2 and LiF microcubes for all OF measurements. Moreover, it has been shown that these passive dosimeters do not require correction factors and can then be used as reference

  13. Small fields output factors measurements and correction factors determination for several detectors for a CyberKnife{sup Registered-Sign} and linear accelerators equipped with microMLC and circular cones

    Energy Technology Data Exchange (ETDEWEB)

    Bassinet, C.; Huet, C.; Derreumaux, S.; Baumann, M.; Trompier, F.; Roch, P.; Clairand, I. [Institut de Radioprotection et de Surete Nucleaire (IRSN), BP17, 92262 Fontenay-aux-Roses Cedex (France); Brunet, G.; Gaudaire-Josset, S. [Institut de Cancerologie de l' Ouest Rene Gauducheau, bd Jacques Monod, 44805 Saint Herblain Cedex (France); Chea, M.; Boisserie, G. [Groupe Hospitalier Pitie-Salpetriere, 47/83 bd de l' Hopital, 75651 Paris Cedex 13 (France); Lacornerie, T. [Centre Oscar Lambret, 3, rue Frederic Combemale, BP 307, 59020 Lille Cedex (France)

    2013-07-15

    Purpose: The use of small photon fields is now an established practice in stereotactic radiosurgery and radiotherapy. However, due to a lack of lateral electron equilibrium and high dose gradients, it is difficult to accurately measure the dosimetric quantities required for the commissioning of such systems. Moreover, there is still no metrological dosimetric reference for this kind of beam today. In this context, the first objective of this work was to determine and to compare small fields output factors (OF) measured with different types of active detectors and passive dosimeters for three types of facilities: a CyberKnife{sup Registered-Sign} system, a dedicated medical linear accelerator (Novalis) equipped with m3 microMLC and circular cones, and an adaptive medical linear accelerator (Clinac 2100) equipped with an additional m3 microMLC. The second one was to determine the k{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}} correction factors introduced in a recently proposed small field dosimetry formalism for different active detectors.Methods: Small field sizes were defined either by microMLC down to 6 Multiplication-Sign 6 mm{sup 2} or by circular cones down to 4 mm in diameter. OF measurements were performed with several commercially available active detectors dedicated to measurements in small fields (high resolution diodes: IBA SFD, Sun Nuclear EDGE, PTW 60016, PTW 60017; ionizing chambers: PTW 31014 PinPoint chamber, PTW 31018 microLion liquid chamber, and PTW 60003 natural diamond). Two types of passive dosimeters were used: LiF microcubes and EBT2 radiochromic films.Results: Significant differences between the results obtained by several dosimetric systems were observed, particularly for the smallest field size for which the difference in the measured OF reaches more than 20%. For passive dosimeters, an excellent agreement was observed (better than 2%) between EBT2 and LiF microcubes

  14. Throw caution to the winds. Recommendation on acceleration of the transition to a sustainable energy economy in the Netherlands; Remmen los. Advies over versnelling van de transitie naar een duurzame energiehuishouding in Nederland

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-10-15

    With regard to the title subject several councils in the Netherlands formulated recommendations for five roads to follow to remove constraints of the present system and accelerate the transition to a sustainable energy economy: (1) Set up a mandatory and consistent goal for a sustainable energy system in 2050, preferably in a European context, but otherwise national; (2) Set up a charter between government, business and civil society with a long term strategy for making sustainable the energy-intensive industry and the fossil energy sector in the Netherlands; (3) use a wider framework for the debate on the usefulness and the need for energy transition in the Netherlands; (4) Stimulate markets for energy conservation and renewable energy; (5) Take away legal and institutional barriers to energy transition. [Dutch] De raden geven aanbevelingen voor vijf noodzakelijk te bewandelen wegen die belemmeringen van het bestaande systeem wegnemen en de transitie naar een duurzame energiehuishouding versnellen: (1) Stel een bindend en consistent doel vast voor een duurzame energiehuishouding in 2050, bij voorkeur in Europees verband maar anders nationaal; (2) Stel een charter op tussen overheid, bedrijven en maatschappelijke organisaties met een langetermijnstrategie voor de verduurzaming dan wel afbouw van energie-intensieve bedrijvigheid en de fossiele energiesector in Nederland; (3) Hanteer een breder frame voor het debat over nut en noodzaak van de energietransitie in Nederland; (4) Stimuleer markten voor energiebesparing en hernieuwbare energie; (5) Neem juridische en institutionele barrieres voor energietransitie weg.

  15. Combined troponin I Ser-150 and Ser-23/24 phosphorylation sustains thin filament Ca(2+) sensitivity and accelerates deactivation in an acidic environment.

    Science.gov (United States)

    Nixon, Benjamin R; Walton, Shane D; Zhang, Bo; Brundage, Elizabeth A; Little, Sean C; Ziolo, Mark T; Davis, Jonathan P; Biesiadecki, Brandon J

    2014-07-01

    The binding of Ca(2+) to troponin C (TnC) in the troponin complex is a critical step regulating the thin filament, the actin-myosin interaction and cardiac contraction. Phosphorylation of the troponin complex is a key regulatory mechanism to match cardiac contraction to demand. Here we demonstrate that phosphorylation of the troponin I (TnI) subunit is simultaneously increased at Ser-150 and Ser-23/24 during in vivo myocardial ischemia. Myocardial ischemia decreases intracellular pH resulting in depressed binding of Ca(2+) to TnC and impaired contraction. To determine the pathological relevance of these simultaneous TnI phosphorylations we measured individual TnI Ser-150 (S150D), Ser-23/24 (S23/24D) and combined (S23/24/150D) pseudo-phosphorylation effects on thin filament regulation at acidic pH similar to that in myocardial ischemia. Results demonstrate that while acidic pH decreased thin filament Ca(2+) binding to TnC regardless of TnI composition, TnI S150D attenuated this decrease rendering it similar to non-phosphorylated TnI at normal pH. The dissociation of Ca(2+) from TnC was unaltered by pH such that TnI S150D remained slow, S23/24D remained accelerated and the combined S23/24/150D remained accelerated. This effect of the combined TnI Ser-150 and Ser-23/24 pseudo-phosphorylations to maintain Ca(2+) binding while accelerating Ca(2+) dissociation represents the first post-translational modification of troponin by phosphorylation to both accelerate thin filament deactivation and maintain Ca(2+) sensitive activation. These data suggest that TnI Ser-150 phosphorylation induced attenuation of the pH-dependent decrease in Ca(2+) sensitivity and its combination with Ser-23/24 phosphorylation to maintain accelerated thin filament deactivation may impart an adaptive role to preserve contraction during acidic ischemia pH without slowing relaxation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Combined Troponin I Ser-150 and Ser-23/24 Phosphorylation Sustains Thin Filament Ca2+ Sensitivity and Accelerates Deactivation in an Acidic Environment*

    Science.gov (United States)

    Nixon, Benjamin R.; Walton, Shane D.; Zhang, Bo; Brundage, Elizabeth A.; Little, Sean C.; Ziolo, Mark T.; Davis, Jonathan P.; Biesiadecki, Brandon J.

    2014-01-01

    The binding of Ca2+ to troponin C (TnC) in the troponin complex is a critical step regulating the thin filament, the actin-myosin interaction and cardiac contraction. Phosphorylation of the troponin complex is a key regulatory mechanism to match cardiac contraction to demand. Here we demonstrate phosphorylation of the troponin I (TnI) subunit is simultaneously increased at Ser-150 and Ser-23/24 during in vivo myocardial ischemia. Myocardial ischemia decreases intracellular pH resulting in depressed binding of Ca2+ to TnC and impaired contraction. To determine the pathological relevance of simultaneous TnI phosphorylation we measured individual TnI Ser-150 (S150D), Ser-23/24 (S23/24D) and combined (S23/24/150D) pseudo-phosphorylation effects on thin filament regulation at acidic pH similar to that in myocardial ischemia. Results demonstrate that while acidic pH decreased thin filament Ca2+ binding to TnC regardless of TnI composition, TnI S150D attenuated this decrease rendering it similar to non-phosphorylated TnI at normal pH. The dissociation of Ca2+ from TnC was unaltered by pH such that TnI S150D remained slow, S23/24D remained accelerated and the combined S23/24/150D remained accelerated. This effect of the combined TnI Ser-150 and Ser-23/24 pseudo-phosphorylation to maintain Ca2+ binding while accelerating Ca2+ dissociation represents the first post-translational modification of troponin by phosphorylation to both accelerate thin filament deactivation and maintain Ca2+ sensitive activation. These data suggest TnI Ser-150 phosphorylation attenuation of the pH-dependent decrease in Ca2+ sensitivity and its combination with Ser-23/24 phosphorylation to maintain accelerated thin filament deactivation may impart an adaptive role to preserve contraction during acidic ischemia pH without slowing relaxation. PMID:24657721

  17. Linear collider: a preview

    Energy Technology Data Exchange (ETDEWEB)

    Wiedemann, H.

    1981-11-01

    Since no linear colliders have been built yet it is difficult to know at what energy the linear cost scaling of linear colliders drops below the quadratic scaling of storage rings. There is, however, no doubt that a linear collider facility for a center of mass energy above say 500 GeV is significantly cheaper than an equivalent storage ring. In order to make the linear collider principle feasible at very high energies a number of problems have to be solved. There are two kinds of problems: one which is related to the feasibility of the principle and the other kind of problems is associated with minimizing the cost of constructing and operating such a facility. This lecture series describes the problems and possible solutions. Since the real test of a principle requires the construction of a prototype I will in the last chapter describe the SLC project at the Stanford Linear Accelerator Center.

  18. Linear accelerator stereotactic radiosurgery for trigeminal neuralgia

    National Research Council Canada - National Science Library

    Varela-Lema, Leonor; Lopez-Garcia, Marisa; Maceira-Rozas, Maria; Munoz-Garzon, Victor

    2015-01-01

    Stereotactic radiosurgery is accepted as an alternative for patients with refractory trigeminal neuralgia, but existing evidence is fundamentally based on the Gamma Knife, which is a specific device...

  19. Wake fields and instabilities in linear accelerators

    CERN Document Server

    Ferrario, M; Palumbo, L

    2006-01-01

    A charged particle beam travelling across perfectly conducting structures whose boundaries do not have constant cross section, such as an RF cavity or bellows, generates longitudinal and transverse wake fields. We discuss in this lecture the general features of wake fields, and show a few simple examples in cylindrical geometry: perfectly conducting pipe and the resonant modes of an RF cavity. We then study the effect of wake fields on the dynamics of a beam in a linac, such as beam break-up instabilities and how to cure them.

  20. ORELA performance. [Oak Ridge Electron Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, T.A.

    1976-04-01

    The most recent information concerning the performance of ORELA that would be of interest to experimenters is presented. Included are characteristics of the beam in terms of both time and intensity and descriptions of systems routinely used to monitor these beam characteristics. For example, with klystron power and maximum electron gun output current at nominal values and for pulse repetition rates in the range above 800 pps, output beam energies per pulse vary from 5 J for 2.5 nsec-wide pulses to approximately 32 J for 10 nsec pulses and 65 J for 40 nsec pulses.

  1. Linear accelerator development at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Batchelor, K

    1976-01-01

    A description is given of operating experience on the 200 MeV Proton Injector Linace of the A.G.S. emphasizing developments in field phase and amplitude control and beam diagnostics. Developments in auxilliary use of the machine are also described.

  2. CLIC: developing a linear collider

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    Compact Linear Collider (CLIC) is a CERN project to provide high-energy electron-positron collisions. Instead of conventional radio-frequency klystrons, CLIC will use a low-energy, high-intensity primary beam to produce acceleration.

  3. Sensitivity analysis the influence of the average energy and FWHM of the initial fluence electrons in the determination of a spectrum of photons Bremsstrahlung of a linear accelerator; Analisis de sensibilidad de la influencia de la energia media y FWHM de la fluencia inicial de electrones en la determinacion de un espectro de fotones Bremsstrahlung de accelerador lineal

    Energy Technology Data Exchange (ETDEWEB)

    Justo, B.; Miro, R.; Verdu, G.; Diez, S.; Campayo, J. M.

    2011-07-01

    The main objective of this work is to study the effects of the initial beam characteristics of electrons in the absorbed dose distribution calculated by Monte Carlo for a photons beam of 6 MeV emitted by a medical linear accelerator.

  4. Future accelerators (?)

    Energy Technology Data Exchange (ETDEWEB)

    John Womersley

    2003-08-21

    I describe the future accelerator facilities that are currently foreseen for electroweak scale physics, neutrino physics, and nuclear structure. I will explore the physics justification for these machines, and suggest how the case for future accelerators can be made.

  5. On the existence of low-energy photons (<150 keV) in the unflattened x-ray beam from an ordinary radiotherapeutic target in a medical linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Tsechanski, A [Department of Nuclear Engineering, Ben-Gurion University of the Negev, POB 653, Beer Sheva 84105 (Israel); Clalit-Biomedical Engineering Ltd, POB 730, Or-Yehuda 60200 (Israel); Krutman, Y [Medical Physics Unit, Rabin Medical Center, Petach-Tikvah 49100 (Israel); Faermann, S [Department of Oncology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, POB 151, Beer-Sheva 84105 (Israel)

    2005-12-07

    Low-energy photons (<150 keV) are essential for obtaining high quality x-ray radiographs. These photons are usually produced in the accelerator target, but are effectively absorbed by the flattening filter and, at least partially, by the target itself. Experimental proof is presented for the existence of low-energy photons in the unflattened x-ray beam produced by a 6 MeV electron beam normally incident on the thinner of the two existing ports of the all-Cu radiotherapeutic target of a Clinac 18 (Varian Associates) linear accelerator. A number of one-shot absorption measurements were carried out with 12 foils of Pb absorbers with thicknesses varying from 0.25 to 3 mm in steps of 0.25 mm arranged symmetrically around the central axis on a 7.2 cm radius circumference. A Kodak ECL film-screen-cassette combination was used as a detector in the absorption measurements, in which optical density was measured as a function of the thickness of the Pb absorbers. Two sets of absorption measurements were carried out: the first one with the Clinac 18 6 MV unflattened beam and the second one with the Clinac 600C 6 MV therapeutic counterpart beam. There is a striking difference between the two sets: the optical density versus Pb-absorber thickness curve shows a sharp increase in optical density at small absorber thicknesses in the case of the unflattened 6 MV x-ray beam as compared with a gently sloping dependence in the case of the 6 MV therapeutic beam. A semi-quantitative assessment of the low-energy photon contribution to the whole optical density/contrast is presented. A 0.85 mm thick Pb absorber intercepting the 6 MV unflattened x-ray beam eliminates almost totally the sharp peak in the optical density curve at small Pb-absorber thicknesses. This constitutes additional evidence for the existence of low-energy photons (<150 keV) in the unflattened 6 MV beam from the Cu therapeutic target.

  6. Collective accelerator for electron colliders

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, R.J.

    1985-05-13

    A recent concept for collective acceleration and focusing of a high energy electron bunch is discussed, in the context of its possible applicability to large linear colliders in the TeV range. The scheme can be considered to be a member of the general class of two-beam accelerators, where a high current, low voltage beam produces the acceleration fields for a trailing high energy bunch.

  7. NIIEFA accelerators for applied purposes

    Science.gov (United States)

    Vorogushin, M. F.; Strokach, A. P.; Filatov, O. G.

    2016-12-01

    Since the foundation of the institute, we have designed and delivered more than three hundred different accelerators to Russia and abroad: cyclotrons, linear accelerators, and neutron generators. The technical characteristics of our equipment makes it competitive on the international market. Here we present the application, main parameters, and status of accelerators manufactured by NIIEFA, as well as prospects for the development of electrophysical systems for applied purposes.

  8. Nanocapsules based on linear and Y-shaped 3-miktoarm star-block PEO-PCL copolymers as sustained delivery system for hydrophilic molecules.

    Science.gov (United States)

    Maglio, Giovanni; Nicodemi, Fabio; Conte, Claudia; Palumbo, Rosario; Tirino, Pasquale; Panza, Elisabetta; Ianaro, Angela; Ungaro, Francesca; Quaglia, Fabiana

    2011-12-12

    Well-defined amphiphilic Y-shaped miktoarm star-block copolymers of PEO and PCL were synthesized by ring-opening polymerization of ε-caprolactone initiated by a PEO-bound lysine macroinitiator. The copolymers were characterized by (1)H NMR, SEC, DSC, and WAXD techniques. Separate PCL and PEO crystalline phases occur in melt-crystallized copolymers when their segmental lengths were comparable and the PCL content was ≤80 wt %. Self-assembling of these copolymers in aqueous medium led to nanoaggregates with low critical aggregation concentration values (0.35 to 1.6 mg·L(-1)) and size depending on composition. Despite the fact that copolymers were not prone to self-organize in vesicles, once processed by a novel w/o emulsion-melting-sonication technique, they gave nanocapsules with a water core and a hydrophilic surface. A macromolecular fluorescent dye was effectively loaded and released at sustained rate by optimizing nanocapsule formulation. The results demonstrate that amphiphilic block copolymers can be assembled in different kinds of nanomorphologies independently of their hydrophilic/hydrophobic balance and architecture through specifically designed preparation techniques.

  9. Comparative study between output factors obtained in a linear accelerator used for radiosurgery treatments; Estudio comparativo entre factores de campo obtenidos en un acelerador lineal usado para tratamientos con radiocirugía

    Energy Technology Data Exchange (ETDEWEB)

    Velázquez Trejo, J.J.; Olive, K.I.; Gutiérrez Castillo, J.G.; Hardy Pérez, A.E.

    2017-11-01

    Purpose: To compare the output factors obtained in a linear accelerator with conical collimators using five models of detectors, through tree different methods: the ratio of detector readings, the “daisy chain” technique (for diodes) and applying the k fclin, fmsr Qclin, Qmsr factors based in the formalism proposed by the IAEA (this one was applied only to tree detectors). Methods: A linear accelerator Varian-iX was employed with BrainLab conical collimators (30 mm to 7.5 mm), the detectors used were: PTW-PinPoint 31016 (×2), PTW-tipo E 60017 (×2), PTW-microLion 31018 (×2), EDGE (Sun-Nuclear), y PTW-Semiflex 31010. For the first three models were analyzed two detectors with different series. The measurements were carried out in water at depth of 1.5 cm and source to surface distance of 98.5 cm. Results: With the readings ratio method, all detectors showed differences from 3.5% to more than 15% in the smallest field sizes, for the diodes the “daisy chain” method did not provide significant corrections. Applying the k fclin, fmsr Qclin, Qmsr Small the detectors PTW60017, PTW31018 and EDGE showed differences of less than 3%. Conclusions: In small fields the readings ratio method could introduce significant errors in the output factor determination. Applying the k fclin, fmsr Qclin, Qmsr proved to be a viable option. [Spanish] Objetivo: Comparar los factores de campo obtenidos en un acelerador lineal con colimadores cónicos utilizando cinco modelos de detectores, mediante tres métodos distintos: a través del cociente entre lecturas de los detectores, con la técnica “daisy chain” (para diodos) y aplicando los factores k fclin, fmsr Qclin, Qmsr basados en el formalismo propuesto por la IAEA (sólo a tres detectores). Métodos: Se empleó un acelerador lineal Varian-iX con colimadores cónicos BrainLab (30mm a 7.5mm), los detectores utilizados fueron: PTW-PinPoint 31016 (×2), PTW-tipo E 60017 (×2), PTW-microLion 31018 (×2), EDGE (Sun-Nuclear), y PTW

  10. SU-F-J-150: Development of An End-To-End Chain Test for the First-In-Man MR-Guided Treatments with the MRI Linear Accelerator by Using the Alderson Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Hoogcarspel, S; Kerkmeijer, L; Lagendijk, J; Van Vulpen, M; Raaymakers, B [University Medical Center Utrecht, Utrecht, Utrecht (Netherlands)

    2016-06-15

    The Alderson phantom is a human shaped quality assurance tool that has been used for over 30 years in radiotherapy. The phantom can provide integrated tests of the entire chain of treatment planning and delivery. The purpose of this research was to investigate if this phantom can be used to chain test a treatment on the MRI linear accelerator (MRL) which is currently being developed at the UMC Utrecht, in collaboration with Elekta and Philips. The latter was demonstrated by chain testing the future First-in-Man treatments with this system.An Alderson phantom was used to chain test an entire treatment with the MRL. First, a CT was acquired of the phantom with additional markers that are both visible on MR and CT. A treatment plan for treating bone metastases in the sacrum was made. The phantom was consecutively placed in the MRL. For MRI imaging, an 3D volume was acquired. The initially developed treatment plan was then simulated on the new MRI dataset. For simulation, both the MR and CT data was used by registering them together. Before treatment delivery a MV image was acquired and compared with a DRR that was calculated form the MR/CT registration data. Finally, the treatment was delivered. Figure 1 shows both the T1 weighted MR-image of the phantom and the CT that was registered to the MR image. Figure 2 shows both the calculated and measured MV image that was acquired by the MV panel. Figure 3 shows the dose distribution that was simulated. The total elapsed time for the entire procedure excluding irradiation was 13:35 minutes.The Alderson Phantom yields sufficient MR contrast and can be used for full MR guided radiotherapy treatment chain testing. As a result, we are able to perform an end-to-end chain test of the future First-in-Man treatments.

  11. Evaluation of a combined respiratory-gating system comprising the TrueBeam linear accelerator and a new real-time tumor-tracking radiotherapy system: a preliminary study.

    Science.gov (United States)

    Shiinoki, Takehiro; Kawamura, Shinji; Uehara, Takuya; Yuasa, Yuki; Fujimoto, Koya; Koike, Masahiro; Sera, Tatsuhiro; Emoto, Yuki; Hanazawa, Hideki; Shibuya, Keiko

    2016-07-08

    A combined system comprising the TrueBeam linear accelerator and a new real-time, tumor-tracking radiotherapy system, SyncTraX, was installed in our institution. The goals of this study were to assess the capability of SyncTraX in measuring the position of a fiducial marker using color fluoroscopic images, and to evaluate the dosimetric and geometric accuracy of respiratory-gated radiotherapy using this combined system for the simple geometry. For the fundamental evaluation of respiratory-gated radiotherapy using SyncTraX, the following were performed:1) determination of dosimetric and positional characteristics of sinusoidal patterns using a motor-driven base for several gating windows; 2) measurement of time delay using an oscilloscope; 3) positional verification of sinusoidal patterns and the pattern in the case of a lung cancer patient; 4) measurement of the half-value layer (HVL in mm AL), effective kVp, and air kerma, using a solid-state detector for each fluoroscopic condition, to determine the patient dose. The dose profile in a moving phantom with gated radiotherapy having a gating window ≤ 4 mm was in good agreement with that under static conditions for each photon beam. The total time delay between TrueBeam and SyncTraX was system comprising TrueBeam and SyncTraX could track the motion of the fiducial marker and control radiation delivery with reasonable accuracy; therefore, this system provides significant dosimetric improvement. However, patient exposure dose from fluoroscopy was not clinically negligible. © 2016 The Authors.

  12. Exploring an Ecologically Sustainable Scheme for Landscape Restoration of Abandoned Mine Land: Scenario-Based Simulation Integrated Linear Programming and CLUE-S Model.

    Science.gov (United States)

    Zhang, Liping; Zhang, Shiwen; Huang, Yajie; Cao, Meng; Huang, Yuanfang; Zhang, Hongyan

    2016-03-24

    Understanding abandoned mine land (AML) changes during land reclamation is crucial for reusing damaged land resources and formulating sound ecological restoration policies. This study combines the linear programming (LP) model and the CLUE-S model to simulate land-use dynamics in the Mentougou District (Beijing, China) from 2007 to 2020 under three reclamation scenarios, that is, the planning scenario based on the general land-use plan in study area (scenario 1), maximal comprehensive benefits (scenario 2), and maximal ecosystem service value (scenario 3). Nine landscape-scale graph metrics were then selected to describe the landscape characteristics. The results show that the coupled model presented can simulate the dynamics of AML effectively and the spatially explicit transformations of AML were different. New cultivated land dominates in scenario 1, while construction land and forest land account for major percentages in scenarios 2 and 3, respectively. Scenario 3 has an advantage in most of the selected indices as the patches combined most closely. To conclude, reclaiming AML by transformation into more forest can reduce the variability and maintain the stability of the landscape ecological system in study area. These findings contribute to better mapping AML dynamics and providing policy support for the management of AML.

  13. Ambient dose equivalent and personal points due to photoneutrons outside a facility that houses a linear accelerator of 18 MV varian; Equivalente de dosis ambiental y personal debida a fotoneutrones en puntos externos a una instalacion que alberga un acelerador lineal varian de 18 MV

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, S. A.; Barquero, R.; Gomez-Ros, J. M.; Lallena, A. M.; Ponzano, P. E.

    2011-07-01

    The use of linear accelerators (linacs) with energies above 10 MV radiotherapy treatments RT and IMRT, can improve the distribution of the absorbed dose in the treated area, increasing the effectiveness of radiation treatments. However and as shown in the scientific literature, the production of photoneutrons for energies above 10 MeV can contribute to exposure of both patient and occupationally exposed workers and the public in the vicinity of the installation. It is therefore necessary to determine the value of ambient dose equivalent and staff both inside and outside the facilities that house these accelerators, especially for energies of 15 and 18 MV.

  14. Electrostatic accelerators

    OpenAIRE

    Hinterberger, F.

    2006-01-01

    The principle of electrostatic accelerators is presented. We consider Cockcroft– Walton, Van de Graaff and Tandem Van de Graaff accelerators. We resume high voltage generators such as cascade generators, Van de Graaff band generators, Pelletron generators, Laddertron generators and Dynamitron generators. The speci c features of accelerating tubes, ion optics and methods of voltage stabilization are described. We discuss the characteristic beam properties and the variety of possible beams. We ...

  15. Electrostatic accelerators

    CERN Document Server

    Hinterberger, F

    2006-01-01

    The principle of electrostatic accelerators is presented. We consider Cockcroft– Walton, Van de Graaff and Tandem Van de Graaff accelerators. We resume high voltage generators such as cascade generators, Van de Graaff band generators, Pelletron generators, Laddertron generators and Dynamitron generators. The speci c features of accelerating tubes, ion optics and methods of voltage stabilization are described. We discuss the characteristic beam properties and the variety of possible beams. We sketch possible applications and the progress in the development of electrostatic accelerators.

  16. Three-dimensional dielectric photonic crystal structures for laser-driven acceleration

    Directory of Open Access Journals (Sweden)

    Benjamin M. Cowan

    2008-01-01

    Full Text Available We present the design and simulation of a three-dimensional photonic crystal waveguide for linear laser-driven acceleration in vacuum. The structure confines a synchronous speed-of-light accelerating mode in both transverse dimensions. We report the properties of this mode, including sustainable gradient and optical-to-beam efficiency. We present a novel method for confining a particle beam using optical fields as focusing elements. This technique, combined with careful structure design, is shown to have a large dynamic aperture and minimal emittance growth, even over millions of optical wavelengths.

  17. Compact accelerator for medical therapy

    Energy Technology Data Exchange (ETDEWEB)

    Caporaso, George J.; Chen, Yu-Jiuan; Hawkins, Steven A.; Sampayan, Stephen E.; Paul, Arthur C.

    2010-05-04

    A compact accelerator system having an integrated particle generator-linear accelerator with a compact, small-scale construction capable of producing an energetic (.about.70-250 MeV) proton beam or other nuclei and transporting the beam direction to a medical therapy patient without the need for bending magnets or other hardware often required for remote beam transport. The integrated particle generator-accelerator is actuable as a unitary body on a support structure to enable scanning of a particle beam by direction actuation of the particle generator-accelerator.

  18. Accelerating Value Creation with Accelerators

    DEFF Research Database (Denmark)

    Jonsson, Eythor Ivar

    2015-01-01

    accelerator programs. Microsoft runs accelerators in seven different countries. Accelerators have grown out of the infancy stage and are now an accepted approach to develop new ventures based on cutting-edge technology like the internet of things, mobile technology, big data and virtual reality. It is also...... an approach to facilitate implementation and realization of business ideas and is a lucrative approach to transform research into ventures and to revitalize regions and industries in transition. Investors have noticed that the accelerator approach is a way to increase the possibility of success by funnelling...... with the traditional audit and legal universes and industries are examples of emerging potentials both from a research and business point of view to exploit and explore further. The accelerator approach may therefore be an Idea Watch to consider, no matter which industry you are in, because in essence accelerators...

  19. Measurement of the dosimetric parameters for low monitor units in step-and-shoot IMRT delivered by Siemens Artiste linear accelerators; Medida de los parametros dosimetricos para bajo numero de unidades monitor en IMRT segmentada estatica administrada por aceleradores lineales Siemens Artiste

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Rodriguez, C.; Lopez Fernandez, A.; Saez Beltran, M.; Martin Martin, G.; Alonso Iracheta, L.

    2012-07-01

    Absorbed dose linearity and beam stability, both for low monitor units, are important factors for ensuring planned dose delivery in step-and-shoot IMRT. For Siemens Artiste linear accelerators, under IMRT stable irradiation conditions and for a single segment of 20 cm x 20 cm field size, the linearity of the absorbed dose with the monitor units, field flatness and symmetry have been measured for the range between 1 and 10 monitor units. We have found that absorbed dose linearity with monitor units is within 2% down to 2 monitor units and it is about 9% for 1 monitor unit. Flatness and symmetry values show variations within 1% down to 2 monitor units and increase by 9% for lower values. Using our monitor unit distribution per segment in IMRT we estimate that the uncertainty in absorbed dose for a whole treatment due to these factors is less than 1% (k= 3). (Author) 13 refs.

  20. Accelerating Inspire

    CERN Document Server

    AUTHOR|(CDS)2266999

    2017-01-01

    CERN has been involved in the dissemination of scientific results since its early days and has continuously updated the distribution channels. Currently, Inspire hosts catalogues of articles, authors, institutions, conferences, jobs, experiments, journals and more. Successful orientation among this amount of data requires comprehensive linking between the content. Inspire has lacked a system for linking experiments and articles together based on which accelerator they were conducted at. The purpose of this project has been to create such a system. Records for 156 accelerators were created and all 2913 experiments on Inspire were given corresponding MARC tags. Records of 18404 accelerator physics related bibliographic entries were also tagged with corresponding accelerator tags. Finally, as a part of the endeavour to broaden CERN's presence on Wikipedia, existing Wikipedia articles of accelerators were updated with short descriptions and links to Inspire. In total, 86 Wikipedia articles were updated. This repo...

  1. Superconducting Linac and associated accelerator development at ...

    Indian Academy of Sciences (India)

    Abstract. There has been significant progress in the programme to develop a superconducting linear accelerator as a booster for the Pelletron accelerator at the Nuclear Science Centre. This paper presents the current status of the development in all the major components of the accelerator.

  2. Introduction to Accelerator Dynamics

    Science.gov (United States)

    Peggs, Stephen; Satogata, Todd

    2017-08-01

    Preface; 1. Introduction; 2. Linear motion; 3. Strong focusing transverse optics; 4. Longitudinal and off-momentum motion; 5. Action and emittance - one particle or many?; 6. Magnets; 7. RF cavities; 8. Linear errors and their correction; 9. Sextupoles, chromaticity and the Hénon map; 10. Octupoles, detuning and slow extraction; 11. Synchrotron radiation - classical damping; 12. Synchrotron radiation - quantum excitation; 13. Linacs - protons and ions; 14. Linacs - electrons; 15. The beam-beam interaction and 1-D resonances; 16. Routes to chaos; Appendix: selected formulae for accelerator design; References; Index.

  3. Cosmic Acceleration

    Science.gov (United States)

    Bean, Rachel

    2011-03-01

    In this series of lectures we review observational evidence for, and theoretical investigations into, cosmic acceleration and dark energy. The notes are in four sections. First I review the basic cosmological formalism to describe the expansion history of the universe and how distance measures are defined. The second section covers the evidence for cosmic acceleration from cosmic distance measurements. Section 3 discusses the theoretical avenues being considered to explain the cosmological observations. Section 4 discusses how the growth of inhomogeneities and large scale structure observations might help us pin down the theoretical origin of cosmic acceleration.

  4. International Workshop on Linear Colliders 2010

    CERN Multimedia

    CERN. Geneva

    2010-01-01

    IWLC2010 International Workshop on Linear Colliders 2010ECFA-CLIC-ILC joint meeting: Monday 18 October - Friday 22 October 2010Venue: CERN and CICG (International Conference Centre Geneva, Switzerland) This year, the International Workshop on Linear Colliders organized by the European Committee for Future Accelerators (ECFA) will study the physics, detectors and accelerator complex of a linear collider covering both CLIC and ILC options.Contact Workshop Secretariat  IWLC2010 is hosted by CERN

  5. Accelerating regular polygon beams.

    Science.gov (United States)

    Barwick, Shane

    2010-12-15

    Beams that possess high-intensity peaks that follow curved paths of propagation under linear diffraction have recently been shown to have a multitude of interesting uses. In this Letter, a family of phase-only masks is derived, and each mask gives rise to multiple accelerating intensity maxima. The curved paths of the peaks can be described by the vertices of a regular polygon that is centered on the optic axis and expands with propagation.

  6. Horizontal Accelerator

    Data.gov (United States)

    Federal Laboratory Consortium — The Horizontal Accelerator (HA) Facility is a versatile research tool available for use on projects requiring simulation of the crash environment. The HA Facility is...

  7. Accelerated construction

    Science.gov (United States)

    2004-01-01

    Accelerated Construction Technology Transfer (ACTT) is a strategic process that uses various innovative techniques, strategies, and technologies to minimize actual construction time, while enhancing quality and safety on today's large, complex multip...

  8. Linear algebra

    CERN Document Server

    Said-Houari, Belkacem

    2017-01-01

    This self-contained, clearly written textbook on linear algebra is easily accessible for students. It begins with the simple linear equation and generalizes several notions from this equation for the system of linear equations and introduces the main ideas using matrices. It then offers a detailed chapter on determinants and introduces the main ideas with detailed proofs. The third chapter introduces the Euclidean spaces using very simple geometric ideas and discusses various major inequalities and identities. These ideas offer a solid basis for understanding general Hilbert spaces in functional analysis. The following two chapters address general vector spaces, including some rigorous proofs to all the main results, and linear transformation: areas that are ignored or are poorly explained in many textbooks. Chapter 6 introduces the idea of matrices using linear transformation, which is easier to understand than the usual theory of matrices approach. The final two chapters are more advanced, introducing t...

  9. Precise accelerator models using measurements with beam

    OpenAIRE

    Zimmermann, Frank

    2000-01-01

    Precision accelerator models are increasingly important for achieving the design performance of colliders and light sources. An overview is given of procedures and techniques for measuring various parameters of the accelerator model, including the beta function, betatron phase, mismatch, nonlinear detuning, resonance-driving terms, impedance, linear coupling, dispersion, linear and non-linear chromaticity, momentum compaction and rf voltage. The complementary model-independent analysis is als...

  10. Precise accelerator models using measurements with beam

    CERN Document Server

    Zimmermann, Frank

    2000-01-01

    Precision accelerator models are increasingly important for achieving the design performance of colliders and light sources. An overview is given of procedures and techniques for measuring various parameters of the accelerator model, including the beta function, betatron phase, mismatch, nonlinear detuning, resonance-driving terms, impedance, linear coupling, dispersion, linear and non-linear chromaticity, momentum compaction and rf voltage. The complementary model-independent analysis is also discussed. More details and further information may be found in ref [1].

  11. Linear algebra

    CERN Document Server

    Stoll, R R

    1968-01-01

    Linear Algebra is intended to be used as a text for a one-semester course in linear algebra at the undergraduate level. The treatment of the subject will be both useful to students of mathematics and those interested primarily in applications of the theory. The major prerequisite for mastering the material is the readiness of the student to reason abstractly. Specifically, this calls for an understanding of the fact that axioms are assumptions and that theorems are logical consequences of one or more axioms. Familiarity with calculus and linear differential equations is required for understand

  12. Linear Algebra and Linear Models

    Indian Academy of Sciences (India)

    This monograph provides an introduction to the basic aspects of the theory oflinear estima- tion and that of testing linear hypotheses. The primary objective is to provide a basic knowledge of analysis of linear models to advanced undergraduate or first year Master's students. The second edition virtually covers the same ...

  13. Linear algebra

    CERN Document Server

    Liesen, Jörg

    2015-01-01

    This self-contained textbook takes a matrix-oriented approach to linear algebra and presents a complete theory, including all details and proofs, culminating in the Jordan canonical form and its proof. Throughout the development, the applicability of the results is highlighted. Additionally, the book presents special topics from applied linear algebra including matrix functions, the singular value decomposition, the Kronecker product and linear matrix equations. The matrix-oriented approach to linear algebra leads to a better intuition and a deeper understanding of the abstract concepts, and therefore simplifies their use in real world applications. Some of these applications are presented in detailed examples. In several ‘MATLAB-Minutes’ students can comprehend the concepts and results using computational experiments. Necessary basics for the use of MATLAB are presented in a short introduction. Students can also actively work with the material and practice their mathematical skills in more than 300 exerc...

  14. Linear Models

    CERN Document Server

    Searle, Shayle R

    2012-01-01

    This 1971 classic on linear models is once again available--as a Wiley Classics Library Edition. It features material that can be understood by any statistician who understands matrix algebra and basic statistical methods.

  15. Linear programming

    CERN Document Server

    Solow, Daniel

    2014-01-01

    This text covers the basic theory and computation for a first course in linear programming, including substantial material on mathematical proof techniques and sophisticated computation methods. Includes Appendix on using Excel. 1984 edition.

  16. Linear algebra

    CERN Document Server

    Berberian, Sterling K

    2014-01-01

    Introductory treatment covers basic theory of vector spaces and linear maps - dimension, determinants, eigenvalues, and eigenvectors - plus more advanced topics such as the study of canonical forms for matrices. 1992 edition.

  17. Energy efficiency of laser driven, structure based accelerators

    Directory of Open Access Journals (Sweden)

    R. H. Siemann

    2004-06-01

    Full Text Available The acceleration efficiency of a laser driven linear accelerator is analyzed. The laser power, loss factor, and impedances determine the maximum charge that can be accelerated and the efficiency of that acceleration. The accelerator structure can be incorporated into a laser cavity. The equation for the resultant laser pulse is derived and analyzed. A specific example is presented, and the steady-state laser pulse shapes, acceleration efficiency, and average unloaded gradient are calculated.

  18. Signature energetic analysis of accelerate electron beam after first acceleration station by accelerating stand of Joint Institute for Nuclear Research

    Science.gov (United States)

    Sledneva, A. S.; Kobets, V. V.

    2017-06-01

    The linear electron accelerator based on the LINAC - 800 accelerator imported from the Netherland is created at Joint Institute for Nuclear Research in the framework of the project on creation of the Testbed with an electron beam of a linear accelerator with an energy up to 250 MV. Currently two accelerator stations with a 60 MV energy of a beam are put in operation and the work is to put the beam through accelerating section of the third accelerator station. The electron beam with an energy of 23 MeV is used for testing the crystals (BaF2, CsI (native), and LYSO) in order to explore the opportunity to use them in particle detectors in experiments: Muon g-2, Mu2e, Comet, whose preparation requires a detailed study of the detectors properties such as their irradiation by the accelerator beams.

  19. Accelerator applications in energy and security

    CERN Document Server

    Chou, Weiren

    2015-01-01

    As accelerator science and technology progressed over the past several decades, the accelerators themselves have undergone major improvements in multiple performance factors: beam energy, beam power, and beam brightness. As a consequence, accelerators have found applications in a wide range of fields in our life and in our society. The current volume is dedicated to applications in energy and security, two of the most important and urgent topics in today's world. This volume makes an effort to provide a review as complete and up to date as possible of this broad and challenging subject. It contains overviews on each of the two topics and a series of articles for in-depth discussions including heavy ion accelerator driven inertial fusion, linear accelerator-based ADS systems, circular accelerator-based ADS systems, accelerator-reactor interface, accelerators for fusion material testing, cargo inspection, proton radiography, compact neutron generators and detectors. It also has a review article on accelerator ...

  20. Accelerating sustainability in large-scale facilities

    CERN Multimedia

    Marina Giampietro

    2011-01-01

    Scientific research centres and large-scale facilities are intrinsically energy intensive, but how can big science improve its energy management and eventually contribute to the environmental cause with new cleantech? CERN’s commitment to providing tangible answers to these questions was sealed in the first workshop on energy management for large scale scientific infrastructures held in Lund, Sweden, on the 13-14 October.   Participants at the energy management for large scale scientific infrastructures workshop. The workshop, co-organised with the European Spallation Source (ESS) and  the European Association of National Research Facilities (ERF), tackled a recognised need for addressing energy issues in relation with science and technology policies. It brought together more than 150 representatives of Research Infrastrutures (RIs) and energy experts from Europe and North America. “Without compromising our scientific projects, we can ...

  1. Sustained and Transient Vestibular Systems: A Physiological Basis for Interpreting Vestibular Function

    OpenAIRE

    Curthoys, Ian S.; MacDougall, Hamish G; Vidal, Pierre-Paul; de Waele, Catherine

    2017-01-01

    Otolithic afferents with regular resting discharge respond to gravity or low-frequency linear accelerations, and we term these the static or sustained otolithic system. However, in the otolithic sense organs, there is anatomical differentiation across the maculae and corresponding physiological differentiation. A specialized band of receptors called the striola consists of mainly type I receptors whose hair bundles are weakly tethered to the overlying otolithic membrane. The afferent neurons,...

  2. Diffraction Accelerator Of Charged Particles

    CERN Document Server

    Alekseev, Yu K; Kosarev, A A; Poseryaev, A V; Shvedunov, V I; Vetrov, A A; Zayarniy, D A

    2004-01-01

    We present the results of theoretical and numerical analysis of the physical processes for laser linear accelerator based on two symmetric resonance diffraction gratings with double-sided accelerating field excitation. Structures parameters optimization provides π-mode field amplitude distribution in neighboring diffraction zone. The maximum energy gradient restricted by ablation processes in grating materials is estimated as 1-3 GeV/m. The numerical analyses and analytical approximation of electric and magnetic field structures are done, longitudinal and transverse electron beam dynamics in accelerating systems are considered, wake fields and focusing properties of diffraction gratings are estimated.

  3. Linear regression

    CERN Document Server

    Olive, David J

    2017-01-01

    This text covers both multiple linear regression and some experimental design models. The text uses the response plot to visualize the model and to detect outliers, does not assume that the error distribution has a known parametric distribution, develops prediction intervals that work when the error distribution is unknown, suggests bootstrap hypothesis tests that may be useful for inference after variable selection, and develops prediction regions and large sample theory for the multivariate linear regression model that has m response variables. A relationship between multivariate prediction regions and confidence regions provides a simple way to bootstrap confidence regions. These confidence regions often provide a practical method for testing hypotheses. There is also a chapter on generalized linear models and generalized additive models. There are many R functions to produce response and residual plots, to simulate prediction intervals and hypothesis tests, to detect outliers, and to choose response trans...

  4. Linear algebra

    CERN Document Server

    Sahai, Vivek

    2013-01-01

    Beginning with the basic concepts of vector spaces such as linear independence, basis and dimension, quotient space, linear transformation and duality with an exposition of the theory of linear operators on a finite dimensional vector space, this book includes the concept of eigenvalues and eigenvectors, diagonalization, triangulation and Jordan and rational canonical forms. Inner product spaces which cover finite dimensional spectral theory and an elementary theory of bilinear forms are also discussed. This new edition of the book incorporates the rich feedback of its readers. We have added new subject matter in the text to make the book more comprehensive. Many new examples have been discussed to illustrate the text. More exercises have been included. We have taken care to arrange the exercises in increasing order of difficulty. There is now a new section of hints for almost all exercises, except those which are straightforward, to enhance their importance for individual study and for classroom use.

  5. Linear algebra

    CERN Document Server

    Edwards, Harold M

    1995-01-01

    In his new undergraduate textbook, Harold M Edwards proposes a radically new and thoroughly algorithmic approach to linear algebra Originally inspired by the constructive philosophy of mathematics championed in the 19th century by Leopold Kronecker, the approach is well suited to students in the computer-dominated late 20th century Each proof is an algorithm described in English that can be translated into the computer language the class is using and put to work solving problems and generating new examples, making the study of linear algebra a truly interactive experience Designed for a one-semester course, this text adopts an algorithmic approach to linear algebra giving the student many examples to work through and copious exercises to test their skills and extend their knowledge of the subject Students at all levels will find much interactive instruction in this text while teachers will find stimulating examples and methods of approach to the subject

  6. Sensitivity analysis of the influence of the medium energy and initial fluence FWHM of electron determining a Bremsstrahlung photon spectrum of a linear accelerator; Analisis de sensibilidad de la influencia de la energia media FWHM de la influencia inicial de electrones en la determinacion de un espectro de fotones Bremsstrahlung de un acelerador lineal

    Energy Technology Data Exchange (ETDEWEB)

    Juste, B.; Miro, R.; Verdu, G.; Diez, S.; Campayo, J. M.

    2012-11-01

    A correct dose calculation in patient under radiotherapy treatments requires and accurate description of the radiation source. The main goal of the present work is to study the effects of initial electron beam characteristics on Monte Carlo calculated absorbed dose distribution for a 6 MeV linac photon beam. To that, we propose a methodology to determine the initial electron fluence before hitting the accelerator target for an Elektra Precis a medical linear accelerator. The method used for the electron radiation source description is based on a Software for Uncertainty and Sensitivity Analysis (SUSA) and Monte Carlo simulations using the MCNP5 transport code. This electron spectrum has been validated by means of comparison of its resulting depth dose curve in a water cube with experimental data being the mean difference below the 1%. (Author)

  7. Linear algebra

    CERN Document Server

    Allenby, Reg

    1995-01-01

    As the basis of equations (and therefore problem-solving), linear algebra is the most widely taught sub-division of pure mathematics. Dr Allenby has used his experience of teaching linear algebra to write a lively book on the subject that includes historical information about the founders of the subject as well as giving a basic introduction to the mathematics undergraduate. The whole text has been written in a connected way with ideas introduced as they occur naturally. As with the other books in the series, there are many worked examples.Solutions to the exercises are available onlin

  8. Study of technical and economic feasibility of using a portal dosimetry system for quality control of linear accelerators; Estudio de viabilidad tecnica y economica del uso de un sistema de dosimetria portal para el control de calidad de aceleradores lineales

    Energy Technology Data Exchange (ETDEWEB)

    Fax, X.; Piro, N.; Sanchez, N.; Toribio, I.; Hermida, M.; Seioane, A.; Saez, J.; Beltran, M.

    2011-07-01

    We have studied the feasibility of Varian portal vision system AS500-II, dosimetry calibration mode, as a substitute for radiochromic plates in quality control tests that required the use of such film. Over a period of two months have been analyzed both the dosimetric characteristics of the system and the mechanical positioning. In addition there has been a financial estimate of annual savings that would result from replacing the radiochromic film by the portal system in a multi-energy accelerator.

  9. Operational Experience of Cooling Water Systems for Accelerator Components at PLS

    CERN Document Server

    Kim, Kyungryul; Kim, Young-Chan; Lee, Bongho; Sik Han, Hong; Soo Ko In; Wha Chung, Chin

    2005-01-01

    The cooling water system has been utilized for absorbing heat generated by a multitude of electromagnetic power delivering networks at PLS. The separate cooling water distribution systems for the storage ring, beam transport line and linear accelerator have been operated with a different operating temperature of supplying water. All water used for heat removal from the accelerator components are deionised and filtered to provide with over 2 MO-cm specific resistance. The operating pressures and flows of input water are also controlled with flow balancing scheme at a specified range. The operating temperature of components in the accelerator is sustained as tight as below ±0.1 deg C to minimize the influence of temperature fluctuation on the beam energy and stability. Although the PLS cooling systems were initially installed with a high degree of flexibility to allow for easy maintenance, a number of system improvements have been employed to enhance operational reliability and to incorporate the newly...

  10. The Spallation Neutron Source accelerator system design

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, S., E-mail: stuarth@fnal.gov [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Abraham, W. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Aleksandrov, A. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Allen, C. [Techsource, Inc., 1475 Central Avenue, Suite 250, Los Alamos, NM 87544-3291 (United States); Alonso, J. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Anderson, D. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Arenius, D. [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Avenue, Newport News, VA 23606 (United States); Arthur, T. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Assadi, S. [Techsource, Inc., 1475 Central Avenue, Suite 250, Los Alamos, NM 87544-3291 (United States); Ayers, J.; Bach, P. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Badea, V. [Brookhaven National Laboratory, P.O. Box 5000, Upton, NY 11973-5000 (United States); Battle, R. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Beebe-Wang, J. [Brookhaven National Laboratory, P.O. Box 5000, Upton, NY 11973-5000 (United States); Bergmann, B.; Bernardin, J.; Bhatia, T.; Billen, J.; Birke, T.; Bjorklund, E. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); and others

    2014-11-01

    The Spallation Neutron Source (SNS) was designed and constructed by a collaboration of six U.S. Department of Energy national laboratories. The SNS accelerator system consists of a 1 GeV linear accelerator and an accumulator ring providing 1.4 MW of proton beam power in microsecond-long beam pulses to a liquid mercury target for neutron production. The accelerator complex consists of a front-end negative hydrogen-ion injector system, an 87 MeV drift tube linear accelerator, a 186 MeV side-coupled linear accelerator, a 1 GeV superconducting linear accelerator, a 248-m circumference accumulator ring and associated beam transport lines. The accelerator complex is supported by ∼100 high-power RF power systems, a 2 K cryogenic plant, ∼400 DC and pulsed power supply systems, ∼400 beam diagnostic devices and a distributed control system handling ∼100,000 I/O signals. The beam dynamics design of the SNS accelerator is presented, as is the engineering design of the major accelerator subsystems.

  11. The Spallation Neutron Source accelerator system design

    Science.gov (United States)

    Henderson, S.; Abraham, W.; Aleksandrov, A.; Allen, C.; Alonso, J.; Anderson, D.; Arenius, D.; Arthur, T.; Assadi, S.; Ayers, J.; Bach, P.; Badea, V.; Battle, R.; Beebe-Wang, J.; Bergmann, B.; Bernardin, J.; Bhatia, T.; Billen, J.; Birke, T.; Bjorklund, E.; Blaskiewicz, M.; Blind, B.; Blokland, W.; Bookwalter, V.; Borovina, D.; Bowling, S.; Bradley, J.; Brantley, C.; Brennan, J.; Brodowski, J.; Brown, S.; Brown, R.; Bruce, D.; Bultman, N.; Cameron, P.; Campisi, I.; Casagrande, F.; Catalan-Lasheras, N.; Champion, M.; Champion, M.; Chen, Z.; Cheng, D.; Cho, Y.; Christensen, K.; Chu, C.; Cleaves, J.; Connolly, R.; Cote, T.; Cousineau, S.; Crandall, K.; Creel, J.; Crofford, M.; Cull, P.; Cutler, R.; Dabney, R.; Dalesio, L.; Daly, E.; Damm, R.; Danilov, V.; Davino, D.; Davis, K.; Dawson, C.; Day, L.; Deibele, C.; Delayen, J.; DeLong, J.; Demello, A.; DeVan, W.; Digennaro, R.; Dixon, K.; Dodson, G.; Doleans, M.; Doolittle, L.; Doss, J.; Drury, M.; Elliot, T.; Ellis, S.; Error, J.; Fazekas, J.; Fedotov, A.; Feng, P.; Fischer, J.; Fox, W.; Fuja, R.; Funk, W.; Galambos, J.; Ganni, V.; Garnett, R.; Geng, X.; Gentzlinger, R.; Giannella, M.; Gibson, P.; Gillis, R.; Gioia, J.; Gordon, J.; Gough, R.; Greer, J.; Gregory, W.; Gribble, R.; Grice, W.; Gurd, D.; Gurd, P.; Guthrie, A.; Hahn, H.; Hardek, T.; Hardekopf, R.; Harrison, J.; Hatfield, D.; He, P.; Hechler, M.; Heistermann, F.; Helus, S.; Hiatt, T.; Hicks, S.; Hill, J.; Hill, J.; Hoff, L.; Hoff, M.; Hogan, J.; Holding, M.; Holik, P.; Holmes, J.; Holtkamp, N.; Hovater, C.; Howell, M.; Hseuh, H.; Huhn, A.; Hunter, T.; Ilg, T.; Jackson, J.; Jain, A.; Jason, A.; Jeon, D.; Johnson, G.; Jones, A.; Joseph, S.; Justice, A.; Kang, Y.; Kasemir, K.; Keller, R.; Kersevan, R.; Kerstiens, D.; Kesselman, M.; Kim, S.; Kneisel, P.; Kravchuk, L.; Kuneli, T.; Kurennoy, S.; Kustom, R.; Kwon, S.; Ladd, P.; Lambiase, R.; Lee, Y. Y.; Leitner, M.; Leung, K.-N.; Lewis, S.; Liaw, C.; Lionberger, C.; Lo, C. C.; Long, C.; Ludewig, H.; Ludvig, J.; Luft, P.; Lynch, M.; Ma, H.; MacGill, R.; Macha, K.; Madre, B.; Mahler, G.; Mahoney, K.; Maines, J.; Mammosser, J.; Mann, T.; Marneris, I.; Marroquin, P.; Martineau, R.; Matsumoto, K.; McCarthy, M.; McChesney, C.; McGahern, W.; McGehee, P.; Meng, W.; Merz, B.; Meyer, R.; Meyer, R.; Miller, B.; Mitchell, R.; Mize, J.; Monroy, M.; Munro, J.; Murdoch, G.; Musson, J.; Nath, S.; Nelson, R.; Nelson, R.; O`Hara, J.; Olsen, D.; Oren, W.; Oshatz, D.; Owens, T.; Pai, C.; Papaphilippou, I.; Patterson, N.; Patterson, J.; Pearson, C.; Pelaia, T.; Pieck, M.; Piller, C.; Plawski, T.; Plum, M.; Pogge, J.; Power, J.; Powers, T.; Preble, J.; Prokop, M.; Pruyn, J.; Purcell, D.; Rank, J.; Raparia, D.; Ratti, A.; Reass, W.; Reece, K.; Rees, D.; Regan, A.; Regis, M.; Reijonen, J.; Rej, D.; Richards, D.; Richied, D.; Rode, C.; Rodriguez, W.; Rodriguez, M.; Rohlev, A.; Rose, C.; Roseberry, T.; Rowton, L.; Roybal, W.; Rust, K.; Salazer, G.; Sandberg, J.; Saunders, J.; Schenkel, T.; Schneider, W.; Schrage, D.; Schubert, J.; Severino, F.; Shafer, R.; Shea, T.; Shishlo, A.; Shoaee, H.; Sibley, C.; Sims, J.; Smee, S.; Smith, J.; Smith, K.; Spitz, R.; Staples, J.; Stein, P.; Stettler, M.; Stirbet, M.; Stockli, M.; Stone, W.; Stout, D.; Stovall, J.; Strelo, W.; Strong, H.; Sundelin, R.; Syversrud, D.; Szajbler, M.; Takeda, H.; Tallerico, P.; Tang, J.; Tanke, E.; Tepikian, S.; Thomae, R.; Thompson, D.; Thomson, D.; Thuot, M.; Treml, C.; Tsoupas, N.; Tuozzolo, J.; Tuzel, W.; Vassioutchenko, A.; Virostek, S.; Wallig, J.; Wanderer, P.; Wang, Y.; Wang, J. G.; Wangler, T.; Warren, D.; Wei, J.; Weiss, D.; Welton, R.; Weng, J.; Weng, W.-T.; Wezensky, M.; White, M.; Whitlatch, T.; Williams, D.; Williams, E.; Wilson, K.; Wiseman, M.; Wood, R.; Wright, P.; Wu, A.; Ybarrolaza, N.; Young, K.; Young, L.; Yourd, R.; Zachoszcz, A.; Zaltsman, A.; Zhang, S.; Zhang, W.; Zhang, Y.; Zhukov, A.

    2014-11-01

    The Spallation Neutron Source (SNS) was designed and constructed by a collaboration of six U.S. Department of Energy national laboratories. The SNS accelerator system consists of a 1 GeV linear accelerator and an accumulator ring providing 1.4 MW of proton beam power in microsecond-long beam pulses to a liquid mercury target for neutron production. The accelerator complex consists of a front-end negative hydrogen-ion injector system, an 87 MeV drift tube linear accelerator, a 186 MeV side-coupled linear accelerator, a 1 GeV superconducting linear accelerator, a 248-m circumference accumulator ring and associated beam transport lines. The accelerator complex is supported by ~100 high-power RF power systems, a 2 K cryogenic plant, ~400 DC and pulsed power supply systems, ~400 beam diagnostic devices and a distributed control system handling ~100,000 I/O signals. The beam dynamics design of the SNS accelerator is presented, as is the engineering design of the major accelerator subsystems.

  12. Accelerator research studies

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    The Accelerator Research Studies program at the University of Maryland, sponsored by the Department of Energy under grant number DE-FG05-91ER40642, is currently in the first year of a three-year funding cycle. The program consists of the following three tasks: TASK A, Study of Transport and Longitudinal Compression of Intense, High-Brightness Beams, TASK B, Study of Collective Ion Acceleration by Intense Electron Beams and Pseudospark Produced High Brightness Electron Beams; TASK C, Study of a Gyroklystron High-power Microwave Source for Linear Colliders. In this report we document the progress that has been made during the past year for each of the three tasks.

  13. Laser acceleration

    Science.gov (United States)

    Tajima, T.; Nakajima, K.; Mourou, G.

    2017-02-01

    The fundamental idea of Laser Wakefield Acceleration (LWFA) is reviewed. An ultrafast intense laser pulse drives coherent wakefield with a relativistic amplitude robustly supported by the plasma. While the large amplitude of wakefields involves collective resonant oscillations of the eigenmode of the entire plasma electrons, the wake phase velocity ˜ c and ultrafastness of the laser pulse introduce the wake stability and rigidity. A large number of worldwide experiments show a rapid progress of this concept realization toward both the high-energy accelerator prospect and broad applications. The strong interest in this has been spurring and stimulating novel laser technologies, including the Chirped Pulse Amplification, the Thin Film Compression, the Coherent Amplification Network, and the Relativistic Mirror Compression. These in turn have created a conglomerate of novel science and technology with LWFA to form a new genre of high field science with many parameters of merit in this field increasing exponentially lately. This science has triggered a number of worldwide research centers and initiatives. Associated physics of ion acceleration, X-ray generation, and astrophysical processes of ultrahigh energy cosmic rays are reviewed. Applications such as X-ray free electron laser, cancer therapy, and radioisotope production etc. are considered. A new avenue of LWFA using nanomaterials is also emerging.

  14. Linear programming

    CERN Document Server

    Karloff, Howard

    1991-01-01

    To this reviewer’s knowledge, this is the first book accessible to the upper division undergraduate or beginning graduate student that surveys linear programming from the Simplex Method…via the Ellipsoid algorithm to Karmarkar’s algorithm. Moreover, its point of view is algorithmic and thus it provides both a history and a case history of work in complexity theory. The presentation is admirable; Karloff's style is informal (even humorous at times) without sacrificing anything necessary for understanding. Diagrams (including horizontal brackets that group terms) aid in providing clarity. The end-of-chapter notes are helpful...Recommended highly for acquisition, since it is not only a textbook, but can also be used for independent reading and study. —Choice Reviews The reader will be well served by reading the monograph from cover to cover. The author succeeds in providing a concise, readable, understandable introduction to modern linear programming. —Mathematics of Computing This is a textbook intend...

  15. Accelerating abelian gauge dynamics

    CERN Document Server

    Adler, Stephen Louis

    1991-01-01

    In this paper, we suggest a new acceleration method for Abelian gauge theories based on linear transformations to variables which weight all length scales equally. We measure the autocorrelation time for the Polyakov loop and the plaquette at β=1.0 in the U(1) gauge theory in four dimensions, for the new method and for standard Metropolis updates. We find a dramatic improvement for the new method over the Metropolis method. Computing the critical exponent z for the new method remains an important open issue.

  16. Scientists at Brookhaven contribute to the development of a better electron accelerator

    CERN Multimedia

    2004-01-01

    Scientists working at Brookhaven have developed a compact linear accelerator called STELLA (Staged Electron Laser Acceleration). Highly efficient, it may help electron accelerators become practical tools for applications in industry and medicine, such as radiation therapy (1 page)

  17. Accelerators and the Accelerator Community

    Energy Technology Data Exchange (ETDEWEB)

    Malamud, Ernest; Sessler, Andrew

    2008-06-01

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.

  18. CAS CERN Accelerator School 5th General Accelerator Physics Course

    Science.gov (United States)

    Turner, S.

    1994-01-01

    The fifth CERN Accelerator School (CAS) basic course on General Accelerator Physics was given at the University of Jyvaeskylae, Finland, from 7 to 18 September 1992. Its syllabus was based on the previous similar courses held at Gif-sur-Yvette in 1984, Aarhus 1986, Salamanca 1988 and Juelich 1990, and whose proceedings were published as CERN Reports 85-19, 87-10, 89-05 and 91-04, respectively. However, certain topics were treated in a different way, improved or extended, while new subjects were introduced. As far as the proceedings of this school are concerned the opportunity was taken not only to include the lectures presented but also to select and revise the most appropriate chapters from the previous similar schools. In this way the present volumes constitute a rather complete introduction to all aspects of the design and construction of particle accelerators, including optics, emittance, luminosity, longitudinal and transverse beam dynamics, insertions, chromaticity, transfer lines, resonances, accelerating structures, tune shifts, coasting beams, lifetime, synchrotron radiation, radiation damping, beam-beam effects, diagnostics, cooling, ion and positron sources, RF and vacuum systems, injection and extraction, conventional, permanent and superconducting magnets, cyclotrons, RF linear accelerators, microtrons, as well as applications of particle accelerators (including therapy) and the history of accelerators. See hints under the relevant topics.

  19. CUDA Accelerated LTL Model Checking -­ Revisited

    OpenAIRE

    Bauch, Petr; Ceska, Milan

    2011-01-01

    Recently, the massively parallel architecture has been used to significantly accelerate many computation demanding tasks. For example, in [Baier, Kateon, The MIT Press, 2009; Barnat, Brim, Ceska, ICPADS 2009] we have shown how CUDA technology can be employed to accelerate the process of Linear Temporal Logic (LTL) Model Checking. In this paper we redesign the One-Way-Catch-Them-Young (OWCTY) algorithm [Cerna, Pelanek, SPIN'03] in order to devise a new CUDA accelerated OWCTY algorithm that wil...

  20. The CSU Accelerator and FEL Facility

    NARCIS (Netherlands)

    Milton, S.V.; Biedron, S.G.; Burleson, T.; Carrico, C.; Edelenbos, J.; Hall, C.; Horovitz, K.; Morin, A.; Rand, L.; Sipahi, N.; Sipahi, T.; van der Slot, P.; Yehudah, H.; Dong, A.; Tanaka, T.; Schaa, V.R.W.

    2013-01-01

    The Colorado State University (CSU) Accelerator Facility will include a 6-MeV L-Band electron linear accelerator (linac) with a free-electron laser (FEL) system capable of producing Terahertz (THz) radiation, a laser laboratory, a microwave test stand, and a magnetic test stand. The photocathode

  1. accelerating cavity

    CERN Multimedia

    On the inside of the cavity there is a layer of niobium. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment.

  2. Linear systems

    CERN Document Server

    Bourlès, Henri

    2013-01-01

    Linear systems have all the necessary elements (modeling, identification, analysis and control), from an educational point of view, to help us understand the discipline of automation and apply it efficiently. This book is progressive and organized in such a way that different levels of readership are possible. It is addressed both to beginners and those with a good understanding of automation wishing to enhance their knowledge on the subject. The theory is rigorously developed and illustrated by numerous examples which can be reproduced with the help of appropriate computation software. 60 exe

  3. RF power generation for future linear colliders

    Energy Technology Data Exchange (ETDEWEB)

    Fowkes, W.R.; Allen, M.A.; Callin, R.S.; Caryotakis, G.; Eppley, K.R.; Fant, K.S.; Farkas, Z.D.; Feinstein, J.; Ko, K.; Koontz, R.F.; Kroll, N.; Lavine, T.L.; Lee, T.G.; Miller, R.H.; Pearson, C.; Spalek, G.; Vlieks, A.E.; Wilson, P.B.

    1990-06-01

    The next linear collider will require 200 MW of rf power per meter of linac structure at relatively high frequency to produce an accelerating gradient of about 100 MV/m. The higher frequencies result in a higher breakdown threshold in the accelerating structure hence permit higher accelerating gradients per meter of linac. The lower frequencies have the advantage that high peak power rf sources can be realized. 11.42 GHz appears to be a good compromise and the effort at the Stanford Linear Accelerator Center (SLAC) is being concentrated on rf sources operating at this frequency. The filling time of the accelerating structure for each rf feed is expected to be about 80 ns. Under serious consideration at SLAC is a conventional klystron followed by a multistage rf pulse compression system, and the Crossed-Field Amplifier. These are discussed in this paper.

  4. Sustainable Food & Sustainable Economics

    OpenAIRE

    Alvarez, Mavis Dora

    2012-01-01

    Cuba today is immersed in a very intense process of perfecting its agricultural production structures with the goal of making them more efficient and sustainable in their economic administration and in their social and environmental management. Agricultural cooperatives in Cuba have the responsibility of producing on 73% of the country's farmland. Their contributions are decisive to developing agricultural production and to ensuring more and better food for the population, in addition to redu...

  5. The application of appropriate technologies and systems for sustainable sanitation

    CSIR Research Space (South Africa)

    Duncker, Louiza C

    2014-11-01

    Full Text Available Sustainable development, which encompasses sustainable sanitation, is defined as development that is appropriate, has the specific objectives of accelerated growth, targeted interventions and community mobilisation to eradicate poverty and focuses...

  6. Switch on to sustainability

    CERN Multimedia

    Antonella Del Rosso

    2012-01-01

    Following a series of measures taken to foster a green policy for the Laboratory, CERN Management has recently appointed an Energy Issues Coordinator. While it's hard to imagine magic solutions that would substantially decrease the energy consumption of the research accelerators, it is certainly within our reach to re-use thermal “waste” energy and to optimise infrastructure to become more sustainable and eco-friendly. Real eco-projects are in the making.   CERN's electricity consumption is considerable, equivalent to a third of Geneva's. Over 95% is used by the accelerators and other research facilities. CERN also consumes gas for heating, fuel and gas for cars, and water for sanitary use and accelerator cooling. “It's our responsibility to keep our energy consumption and hence our impact on the environment as low as possible,” says Helfried Burckhart, recently appointed as CERN’s Energy Issues Coordinator. &am...

  7. Advances of Accelerator Physics and Technologies

    CERN Document Server

    1993-01-01

    This volume, consisting of articles written by experts with international repute and long experience, reviews the state of the art of accelerator physics and technologies and the use of accelerators in research, industry and medicine. It covers a wide range of topics, from basic problems concerning the performance of circular and linear accelerators to technical issues and related fields. Also discussed are recent achievements that are of particular interest (such as RF quadrupole acceleration, ion sources and storage rings) and new technologies (such as superconductivity for magnets and RF ca

  8. New accelerators in high-energy physics

    Energy Technology Data Exchange (ETDEWEB)

    Blewett, J.P.

    1982-01-01

    First, I should like to mention a few new ideas that have appeared during the last few years in the accelerator field. A couple are of importance in the design of injectors, usually linear accelerators, for high-energy machines. Then I shall review some of the somewhat sensational accelerator projects, now in operation, under construction or just being proposed. Finally, I propose to mention a few applications of high-energy accelerators in fields other than high-energy physics. I realize that this is a digression from my title but I hope that you will find it interesting.

  9. Implantação de um programa de controle de qualidade de um acelerador linear de 6 MeV de fótons Implementation of a quality control program for a 6 MeV linear photon accelerator

    Directory of Open Access Journals (Sweden)

    Mafalda F. Berdaky

    2001-10-01

    Full Text Available Este trabalho apresenta a parte operacional do processo final envolvido na implantação de um programa de controle de qualidade por meio de testes rotineiros mecânicos e de radiação. O programa de controle de qualidade, durante 35 meses, mostrou a estabilidade excelente deste acelerador.This paper describes the operational characteristics of the final process of implementation of a quality control program using routine mechanical and radiation tests. The quality control program was performed during 35 months and demonstrated the excellent stability of this accelerator.

  10. Progress toward NLC / GLC prototype accelerator structures

    CERN Document Server

    Wang, J W; Arkan, T; Baboi, N; Boffo, C; Bowden, G B; Burke, D L; Carter, H; Chan, J; Cornuelle, J; Döbert, Steffen; Dolgashev, Valery A; Finley, D; Gonin, I; Higashi, Y; Higo, T; Jones, R M; Khabiboulline, T; Kume, T; Lewandowski, J; Li, Z; Miller, R H; Mishra, S; Morozumi, Y; Nantista, C; Pearson, C; Romanov, G; Ruth, Ronald D; Solyak, N; Tantawi, S; Toge, N; Ueno, K; Wilson, P B; Xiao, L

    2004-01-01

    The accelerator structure groups for NLC (Next Linear Collider) and GLC (Global Linear Colliders) have successfully collaborated on the research and development of a major series of advanced accelerator structures based on room-temperature technology at X-band frequency. The progress in design, simulation, microwave measurement and high gradient tests are summarized in this paper. The recent effort in design and fabrication of the accelerator structure prototype for the main linac is presented in detail including HOM (High Order Mode) suppression and couplers, fundamental mode couplers, optimized accelerator cavities as well as plans for future structures. We emphasize techniques to reduce the field on the surface of the copper structures (in order to achieve high accelerating gradients), limit the dipole wakefields (to relax alignment tolerance and prevent a beam break up instability) and improve shunt impedance (to reduce the RF power required).

  11. The financial impact of the incorporation of IMRT and RapidArc™ techniques on shielding calculation of a linear accelerator; O impacto financeiro da incorporacao das tecnicas de IMRT e RapidArc™ no calculo de blindagem de um acelerador linear

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Maira R.; Silveira, Thiago B.; Garcia, Paulo L.; Trindade, Cassia; Martins, Lais P.; Batista, Delano V.S., E-mail: mairafisica@gmail.com [Instituto Nacional do Cancer (INCA), Rio de Janeiro, RJ (Brazil)

    2013-08-15

    Given the new methodology introduced in the shielding calculation due to recent modulated techniques in radiotherapy treatment, it became necessary to evaluate the impact of changes in the accelerator routine using such techniques. Based on a group of 30 patients from the National Cancer Institute (INCA) the workload multiplier factors for intensity modulated radiotherapy (IMRT factor) and for RapidArc™ (RA factor) were established. Four different routines in a 6 MV generic accelerator were proposed to estimate the impact of these modified workloads in the building cost of the secondary barriers. The results indicate that if 50% of patients are treating with IMRT, the secondary barrier becomes 14,1% more expensive than the barrier calculated for conformal treatments exclusive. While RA, in the same proportion, leads to a barrier only 3,7% more expensive. Showing that RA can, while reducing treatment time, increase the proportion of patients treated with modulation technique, without increasing the cost of the barrier, when compared with IMRT. (author)

  12. Gender Differences in Head Impacts Sustained by Collegiate Ice Hockey Players

    Science.gov (United States)

    Brainard, Lindley L.; Beckwith, Jonathan G.; Chu, Jeffrey J.; Crisco, Joseph J.; McAllister, Thomas W.; Duhaime, Ann-Christine; Maerlender, Arthur C.; Greenwald, Richard M.

    2013-01-01

    Purpose This study aims to quantify the frequency, magnitude, and location of head impacts sustained by male and female collegiate ice hockey players over two seasons of play. Methods Over two seasons, 88 collegiate athletes (51 female, 37 male) on two female and male NCAA varsity ice hockey teams wore instrumented helmets. Each helmet was equipped with 6 single-axis accelerometers and a miniature data acquisition system to capture and record head impacts sustained during play. Data collected from the helmets were post-processed to compute linear and rotational acceleration of the head as well as impact location. The head impact exposure data (frequency, location, and magnitude) were then compared across gender. Results Female hockey players experienced a significantly lower (p 0.278) for all locations except the right side of the head, where males received fewer impacts than females (p = 0.031). Female hockey players were 1.1 times more likely than males to sustain an impact less than 50 g while males were 1.3 times more likely to sustain an impact greater than 100 g. Similarly, males were 1.9 times more likely to sustain an impact with peak rotational acceleration greater than 5,000 rad/s2 and 3.5 times more likely to sustain an impact greater than 10,000 rad/s2. Conclusions Although the incidence of concussion has typically been higher for female hockey players than male hockey players, female players sustain fewer impacts and impacts resulting in lower head acceleration than males. Further study is required to better understand the intrinsic and extrinsic risk factors that lead to higher rates of concussion for females that have been previously reported. PMID:21716150

  13. Sustainable Enterprise Excellence and the Continuously Relevant and Responsible Organization

    DEFF Research Database (Denmark)

    Edgeman, Rick; Bøllingtoft, Anne; Eskildsen, Jacob Kjær

    2013-01-01

    issues surrounding enterprise innovation and sustainability efforts and capabilities. Innovation and sustainability of the necessary trajectory, scale, and velocity are strategically integrated to deliver what we refer to as innovating sustainability. This provides an accelerated means path toward...... sustainable enterprise excellence, and hence toward the asymptotic aspiration of being a continuously relevant and responsible organization. Introduced are the concepts of innovating sustainability, sustainable enterprise excellence (SEE), and continuously relevant and responsible organizations (CRRO)....

  14. Scientific computing with multicore and accelerators

    CERN Document Server

    Kurzak, Jakub; Dongarra, Jack

    2010-01-01

    Dense Linear Algebra Implementing Matrix Multiplication on the Cell B.E, Wesley Alvaro, Jakub Kurzak, and Jack DongarraImplementing Matrix Factorizations on the Cell BE, Jakub Kurzak and Jack DongarraDense Linear Algebra for Hybrid GPU-Based Systems, Stanimire Tomov and Jack DongarraBLAS for GPUs, Rajib Nath, Stanimire Tomov, and Jack DongarraSparse Linear Algebra Sparse Matrix-Vector Multiplication on Multicore and Accelerators, Samuel Williams, Nathan B

  15. Determination of the exposure speed of radiation emitted by the linear accelerator, using the code MCNP5 to evaluate the radiotherapy room shields of ABC Hospital; Determinacion de la rapidez de exposicion de la radiacion emitida por el acelerador lineal, utilizando el codigo MCNP5, para evaluar los blindajes de la sala de radioterapia del Hospital ABC

    Energy Technology Data Exchange (ETDEWEB)

    Corral B, J. R.

    2015-07-01

    Humans should avoid exposure to radiation, because the consequences are harmful to health. Although there are different emission sources of radiation, generated by medical devices they are usually of great interest, since people who attend hospitals are exposed in one way or another to ionizing radiation. Therefore, is important to conduct studies on radioactive levels that are generated in hospitals, as a result of the use of medical equipment. To determine levels of exposure speed of a radioactive facility there are different methods, including the radiation detector and computational method. This thesis uses the computational method. With the program MCNP5 was determined the speed of the radiation exposure in the radiotherapy room of Cancer Center of ABC Hospital in Mexico City. In the application of computational method, first the thicknesses of the shields were calculated, using variables as: 1) distance from the shield to the source; 2) desired weekly equivalent dose; 3) weekly total dose equivalent emitted by the equipment; 4) occupation and use factors. Once obtained thicknesses, we proceeded to model the bunker using the mentioned program. The program uses the Monte Carlo code to probabilistic ally determine the phenomena of interaction of radiation with the shield, which will be held during the X-ray emission from the linear accelerator. The results of computational analysis were compared with those obtained experimentally with the detection method, for which was required the use of a Geiger-Muller counter and the linear accelerator was programmed with an energy of 19 MV with 500 units monitor positioning the detector in the corresponding boundary. (Author)

  16. Social Sciences and Sustainability

    Directory of Open Access Journals (Sweden)

    Shu-Kun Lin

    2011-09-01

    Full Text Available At the time when the journal Sustainability [1] was launched, as a chemist and a scientist, I started to believe that social sciences may be more important to make humans sustainable. The broad journal title Social Sciences presents the opportunity for all social science scholars to have integrated consideration regarding the sustainability of humanity, because I am sure that science and technology alone cannot help. Science and technology may have in fact been contributing to accelerate the depletion of nonrenewable natural resources and putting human sustainability at risk since the industrial revolution about 150 years ago. I hope all intellectuals studying anthropology, archaeology, administration, communication, criminology, economics, education, government, linguistics, international relations, politics, sociology and, in some contexts, geography, history, law, and psychology publish with us to seek a solution to sustain humanity. Sustainability itself will also be a main topic of the journal Social Sciences. In addition to this integrated forum for social sciences, more topic specific journals, such as the already publishing Societies [2], will be launched. [...

  17. Biofuels and sustainability.

    Science.gov (United States)

    Solomon, Barry D

    2010-01-01

    Interest in liquid biofuels production and use has increased worldwide as part of government policies to address the growing scarcity and riskiness of petroleum use, and, at least in theory, to help mitigate adverse global climate change. The existing biofuels markets are dominated by U.S. ethanol production based on cornstarch, Brazilian ethanol production based on sugarcane, and European biodiesel production based on rapeseed oil. Other promising efforts have included programs to shift toward the production and use of biofuels based on residues and waste materials from the agricultural and forestry sectors, and perennial grasses, such as switchgrass and miscanthus--so-called cellulosic ethanol. This article reviews these efforts and the recent literature in the context of ecological economics and sustainability science. Several common dimensions for sustainable biofuels are discussed: scale (resource assessment, land availability, and land use practices); efficiency (economic and energy); equity (geographic distribution of resources and the "food versus fuel" debate); socio-economic issues; and environmental effects and emissions. Recent proposals have been made for the development of sustainable biofuels criteria, culminating in standards released in Sweden in 2008 and a draft report from the international Roundtable on Sustainable Biofuels. These criteria hold promise for accelerating a shift away from unsustainable biofuels based on grain, such as corn, and toward possible sustainable feedstock and production practices that may be able to meet a variety of social, economic, and environmental sustainability criteria.

  18. Human Capital and Sustainability

    Directory of Open Access Journals (Sweden)

    Garry Jacobs

    2011-01-01

    Full Text Available A study of sustainability needs to consider the role of all forms of capital—natural, biological, social, technological, financial, cultural—and the complex ways in which they interact. All forms of capital derive their value, utility and application from human mental awareness, creativity and social innovation. This makes human capital, including social capital, the central determinant of resource productivity and sustainability. Humanity has entered the Anthropocene Epoch in which human changes have become the predominant factor in evolution. Humanity is itself evolving from animal physicality to social vitality to mental individuality. This transition has profound bearing on human productive capabilities, adaptability, creativity and values, the organization of economy, public policy, social awareness and life styles that determine sustainability. This article examines the linkages between population, economic development, employment, education, health, social equity, cultural values, energy intensity and sustainability in the context of evolving human consciousness. It concludes that development of human capital is the critical determinant of long-term sustainability and that efforts to accelerate the evolution of human consciousness and emergence of mentally self-conscious individuals will be the most effective approach for ensuring a sustainable future. Education is the primary lever. Human choice matters.

  19. Electron Acceleration in Supernovae and Millimeter Perspectives

    Directory of Open Access Journals (Sweden)

    Keiichi Maeda

    2014-12-01

    Full Text Available Supernovae launch a strong shock wave by the interaction of the expanding ejecta and surrounding circumstellar matter (CSM. At the shock, electrons are accelerated to relativistic speed, creating observed synchrotron emissions in radio wavelengths. In this paper, I suggest that SNe (i.e., < 1 year since the explosion provide a unique site to study the electron acceleration mechanism. I argue that the eciency of the acceleration at the young SN shock is much lower than conventionally assumed, and that the electrons emitting in the cm wavelengths are not fully in the Diffusive Shock Acceleration (DSA regime. Thus radio emissions from young SNe record information on the yet-unresolved 'injection' mechanism. I also present perspectives of millimeter (mm observations of SNe - this will provide opportunities to uniquely determine the shock physics and the acceleration efficiency, to test the non-linear DSA mechanism and provide a characteristic electron energy scale with which the DSA start dominating the electron acceleration.

  20. EDITORIAL: Laser and plasma accelerators Laser and plasma accelerators

    Science.gov (United States)

    Bingham, Robert

    2009-02-01

    This special issue on laser and plasma accelerators illustrates the rapid advancement and diverse applications of laser and plasma accelerators. Plasma is an attractive medium for particle acceleration because of the high electric field it can sustain, with studies of acceleration processes remaining one of the most important areas of research in both laboratory and astrophysical plasmas. The rapid advance in laser and accelerator technology has led to the development of terawatt and petawatt laser systems with ultra-high intensities and short sub-picosecond pulses, which are used to generate wakefields in plasma. Recent successes include the demonstration by several groups in 2004 of quasi-monoenergetic electron beams by wakefields in the bubble regime with the GeV energy barrier being reached in 2006, and the energy doubling of the SLAC high-energy electron beam from 42 to 85 GeV. The electron beams generated by the laser plasma driven wakefields have good spatial quality with energies ranging from MeV to GeV. A unique feature is that they are ultra-short bunches with simulations showing that they can be as short as a few femtoseconds with low-energy spread, making these beams ideal for a variety of applications ranging from novel high-brightness radiation sources for medicine, material science and ultrafast time-resolved radiobiology or chemistry. Laser driven ion acceleration experiments have also made significant advances over the last few years with applications in laser fusion, nuclear physics and medicine. Attention is focused on the possibility of producing quasi-mono-energetic ions with energies ranging from hundreds of MeV to GeV per nucleon. New acceleration mechanisms are being studied, including ion acceleration from ultra-thin foils and direct laser acceleration. The application of wakefields or beat waves in other areas of science such as astrophysics and particle physics is beginning to take off, such as the study of cosmic accelerators considered

  1. Sustainable agriculture

    National Research Council Canada - National Science Library

    Lichtfouse, Eric

    2009-01-01

    ... : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 9 Part I CLIMATE CHANGE Soils and Sustainable Agriculture: A Review : : : : : : : : : : : : : : : : : : : : : : : : : : Rattan Lal 15 Soils and Food Sufficiency...

  2. APT accelerator. Topical report

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, G.; Rusthoi, D. [comp.] [ed.

    1995-03-01

    The Accelerator Production of Tritium (APT) project, sponsored by Department of Energy Defense Programs (DOE/DP), involves the preconceptual design of an accelerator system to produce tritium for the nation`s stockpile of nuclear weapons. Tritium is an isotope of hydrogen used in nuclear weapons, and must be replenished because of radioactive decay (its half-life is approximately 12 years). Because the annual production requirements for tritium has greatly decreased since the end of the Cold War, an alternative approach to reactors for tritium production, based on a linear accelerator, is now being seriously considered. The annual tritium requirement at the time this study was undertaken (1992-1993) was 3/8 that of the 1988 goal, usually stated as 3/8-Goal. Continued reduction in the number of weapons in the stockpile has led to a revised (lower) production requirement today (March, 1995). The production requirement needed to maintain the reduced stockpile, as stated in the recent Nuclear Posture Review (summer 1994) is approximately 3/16-Goal, half the previous level. The Nuclear Posture Review also requires that the production plant be designed to accomodate a production increase (surge) to 3/8-Goal capability within five years, to allow recovery from a possible extended outage of the tritium plant. A multi-laboratory team, collaborating with several industrial partners, has developed a preconceptual APT design for the 3/8-Goal, operating at 75% capacity. The team has presented APT as a promising alternative to the reactor concepts proposed for Complex-21. Given the requirements of a reduced weapons stockpile, APT offers both significant safety, environmental, and production-fexibility advantages in comparison with reactor systems, and the prospect of successful development in time to meet the US defense requirements of the 21st Century.

  3. Sustainable Marketing

    NARCIS (Netherlands)

    Dam, van Y.K.

    2017-01-01

    In this article, three different conceptions of sustainable marketing are discussed and compared. These different conceptions are referred to as social, green, and critical sustainable marketing. Social sustainable marketing follows the logic of demand-driven marketing management and places the

  4. Experiments on Gradient Limits for Normal Conducting Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Dolgashev, Valery A.

    2003-08-11

    The accelerating gradient is one of the crucial parameters affecting the design, construction and cost of next-generation linear accelerators. For a specified final energy, the gradient sets the accelerator length, and for a given accelerating structure and pulse repetition rate, it determines power consumption. In this paper experimental results and problems related to breakdown damage, pulsed heating, application of new materials, as well as difference between standing wave (SW) and traveling wave (TW) structures will be discussed.

  5. Comparative study and selection criteria of linear motors

    OpenAIRE

    Chevailler, Samuel; Jufer, Marcel

    2007-01-01

    Initially, linear motors have been particularly dedicated to transportation systems. Nowadays, linear motors are meant to replace a system using a rotating motor and a transmission to realize a linear movement. With linear motors the performances increase considerably since the mechanical limitations are removed. This leads to a better precision, a higher acceleration and a higher speed of the moving part. Therefore, direct drives with linear motors are increasingly used in industrial applica...

  6. Towards sustainable food production

    DEFF Research Database (Denmark)

    Aramyan, Lusine H; Hoste, Robert; van den Broek, Willie

    2011-01-01

    allocation of pork supply chain activities in Europe. Supply chain production and distribution activities are optimized in various scenarios based on economic and sustainability performance indicators. A mixed integer linear programming (MILP) model, which includes piglet production, fattening, slaughtering......, as minimizing costs will not always lead to an optimal reduction in CO2 equivalent emissions, a differentiated strategy is needed for the European pork sector to move towards more sustainable production......European pork supply chains, like other agri-food supply chains, currently face numerous challenges such as globalization, emerging markets, changing consumer requirements, and new governmental regulations related to issues such as environmental pollution and food safety. These challenges require...

  7. Accelerator and electrodynamics capability review

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Kevin W [Los Alamos National Laboratory

    2010-01-01

    Los Alamos National Laboratory (LANL) uses capability reviews to assess the science, technology and engineering (STE) quality and institutional integration and to advise Laboratory Management on the current and future health of the STE. Capability reviews address the STE integration that LANL uses to meet mission requirements. The Capability Review Committees serve a dual role of providing assessment of the Laboratory's technical contributions and integration towards its missions and providing advice to Laboratory Management. The assessments and advice are documented in reports prepared by the Capability Review Committees that are delivered to the Director and to the Principal Associate Director for Science, Technology and Engineering (PADSTE). Laboratory Management will use this report for STE assessment and planning. LANL has defined fifteen STE capabilities. Electrodynamics and Accelerators is one of the seven STE capabilities that LANL Management (Director, PADSTE, technical Associate Directors) has identified for review in Fiscal Year (FY) 2010. Accelerators and electrodynamics at LANL comprise a blend of large-scale facilities and innovative small-scale research with a growing focus on national security applications. This review is organized into five topical areas: (1) Free Electron Lasers; (2) Linear Accelerator Science and Technology; (3) Advanced Electromagnetics; (4) Next Generation Accelerator Concepts; and (5) National Security Accelerator Applications. The focus is on innovative technology with an emphasis on applications relevant to Laboratory mission. The role of Laboratory Directed Research and Development (LDRD) in support of accelerators/electrodynamics will be discussed. The review provides an opportunity for interaction with early career staff. Program sponsors and customers will provide their input on the value of the accelerator and electrodynamics capability to the Laboratory mission.

  8. Linear Algebra and Smarandache Linear Algebra

    OpenAIRE

    Vasantha, Kandasamy

    2003-01-01

    The present book, on Smarandache linear algebra, not only studies the Smarandache analogues of linear algebra and its applications, it also aims to bridge the need for new research topics pertaining to linear algebra, purely in the algebraic sense. We have introduced Smarandache semilinear algebra, Smarandache bilinear algebra and Smarandache anti-linear algebra and their fuzzy equivalents. Moreover, in this book, we have brought out the study of linear algebra and ve...

  9. Accelerating Research Innovation by Adopting the Lean Startup Paradigm

    National Research Council Canada - National Science Library

    Kaisa Still

    2017-01-01

    .... In this article, we explore how the lean startup paradigm, which validates the market for a product with a business model that can sustain subsequent scaling, has led to a new process model to accelerate innovation...

  10. Radiation Protection in the NLC Test Accelerator at SLAC

    Science.gov (United States)

    Lavine, Theodore L.; Vylet, Vaclav

    1997-05-01

    This paper describes the elements of the design of the NLC Test Accelerator pertaining to ionizing radiation protection and safety. The NLC Test Accelerator is an accelerator physics research facility at SLAC designed to validate 2.6-cm microwave linear accelerator technology for a future high-energy linear collider (the "Next Linear Collider"). The NLC Test Accelerator is designed for average beam power levels up to 1.5 kW, at energies up to 1 GeV (roughly equivalent to 1/500 of an NLC linac). The design for radiation protection incorporates shielding, configuration controls, safety interlock systems for personnel protection and beam containment, and operations procedures. The design was guided by the DOE Accelerator Safety Order, internal Laboratory policy, and the general principle of keeping radiation doses as low as reasonably achievable.

  11. Sustainable Disruptions

    DEFF Research Database (Denmark)

    Friis, Silje Alberthe Kamille; Kjær, Lykke Bloch

    2016-01-01

    Since 2012 the Sustainable Disruptions (SD) project at the Laboratory for Sustainability at Design School Kolding (DK) has developed and tested a set of design thinking tools, specifically targeting the barriers to economically, socially, and environmentally sustainable business development....... The tools have been applied in practice in collaboration with 11 small and medium sized companies (SMEs). The study investigates these approaches to further understand how design thinking can contribute to sustainable transition in a business context. The study and the findings are relevant to organizations...... invested in the issue of sustainable business development, in particular the leaders and employees of SMEs, but also to design education seeking new ways to consciously handle and teach the complexity inherent in sustainable transformation. Findings indicate that the SD design thinking approach contributes...

  12. Piezoelectric particle accelerator

    Science.gov (United States)

    Kemp, Mark A.; Jongewaard, Erik N.; Haase, Andrew A.; Franzi, Matthew

    2017-08-29

    A particle accelerator is provided that includes a piezoelectric accelerator element, where the piezoelectric accelerator element includes a hollow cylindrical shape, and an input transducer, where the input transducer is disposed to provide an input signal to the piezoelectric accelerator element, where the input signal induces a mechanical excitation of the piezoelectric accelerator element, where the mechanical excitation is capable of generating a piezoelectric electric field proximal to an axis of the cylindrical shape, where the piezoelectric accelerator is configured to accelerate a charged particle longitudinally along the axis of the cylindrical shape according to the piezoelectric electric field.

  13. Computational sustainability

    CERN Document Server

    Kersting, Kristian; Morik, Katharina

    2016-01-01

    The book at hand gives an overview of the state of the art research in Computational Sustainability as well as case studies of different application scenarios. This covers topics such as renewable energy supply, energy storage and e-mobility, efficiency in data centers and networks, sustainable food and water supply, sustainable health, industrial production and quality, etc. The book describes computational methods and possible application scenarios.

  14. Sustainable transformation

    DEFF Research Database (Denmark)

    Andersen, Nicolai Bo

    This paper is about sustainable transformation with a particular focus on listed buildings. It is based on the notion that sustainability is not just a question of energy conditions, but also about the building being robust. Robust architecture means that the building can be maintained and rebuilt...... theoretical lenses. It is proposed that three parameters concerning the ꞌtransformabilityꞌ of the building can contribute to a more nuanced understanding of sustainable transformation: technical aspects, programmatic requirements and narrative value. It is proposed that the concept of ꞌsustainable...

  15. Applications of the Strategic Defense Initiative's compact accelerators

    Science.gov (United States)

    Montanarelli, Nick; Lynch, Ted

    1991-01-01

    The Strategic Defense Initiative's (SDI) investment in particle accelerator technology for its directed energy weapons program has produced breakthroughs in the size and power of new accelerators. These accelerators, in turn, have produced spinoffs in several areas: the radio frequency quadrupole linear accelerator (RFQ linac) was recently incorporated into the design of a cancer therapy unit at the Loma Linda University Medical Center, an SDI-sponsored compact induction linear accelerator may replace Cobalt-60 radiation and hazardous ethylene-oxide as a method for sterilizing medical products, and other SDIO-funded accelerators may be used to produce the radioactive isotopes oxygen-15, nitrogen-13, carbon-11, and fluorine-18 for positron emission tomography (PET). Other applications of these accelerators include bomb detection, non-destructive inspection, decomposing toxic substances in contaminated ground water, and eliminating nuclear waste.

  16. Calculation of the structural shielding of the radiotherapy treatment room equipped with a linear accelerator type Tomo therapy Hi-Art in the Oncology Center of Chihuahua, Mexico; Calculo del blindaje estructural de la sala de tratamiento de radioterapia equipada con un acelerador lineal del tipo Tomotherapy Hi-Art en el Centro Oncologico de Chihuahua, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Caballero G, C. A. [Southwest Oncology Centers, North Civic Center Plaza No. 2926, Scottsdale, Arizona (United States); Plascencia, J. C. [Centro Oncologico Louis and Lucille Grado, Republica del Peru No. 102-5, Col. Americas, Aguascalientes (Mexico); Vargas V, M. X.; Toledo J, P., E-mail: cabshm@msn.co [Centro Oncologico de Chihuahua, Hacienda de la Esperanza No. 6304, Fracc. Cima Comercial, Chihuahua (Mexico)

    2010-09-15

    The helicoid tomo therapy is an external radiotherapy system of modulated intensity, guided by image, in which the radiation is imparted to the patient using a narrow radiation beam in helicoid form, in a similar way to the scanning process with a computerized tomography. The tomo therapy equipment (Tomo Therapy Hi-Art) consists in an electrons linear accelerator with acceleration voltages of 6 MV for treatment and 3.5 MV for image, coupled to a ring that turn around the patient as this is transferred through this ring in perpendicular sense to the radiation beam. The radiation beam is narrow because has the maximum size of 5 x 40 cm{sup 2} in the isocenter. The intensity modulation of the beam is carried out with a binary dynamic collimator of 64 crisscross sheets, and the guide by image though a system of megavoltage computerized tomography. Opposed to the radiation beam, also coupled to the rotational ring, a group of lead plates exists with a total thickness of 13 cm that acts as barrier of the primary radiation beam. The special configuration of the tomography equipment makes to have the following characteristics: 1) the presence of the lead barrier of the equipment reduces the intensity of the primary beam that reaches the bunker walls in considerable way, 2) the disperse and leakage radiations are increased with regard to a conventional accelerator due to the increase in the necessary irradiation time to produce modulated intensity fields by means of the narrow radiation beam. These special characteristics of the tomo therapy equipment make that particularities exist in the application of the formulations for structural shielding calculations that appears in the NCRP reports 49, NCRP 151 and IAEA-SRS-47. For this reason, several researches have development analytic models based on geometric considerations of continuous rotation of the equipment ring to determine the shielding requirements for the primary beam, the dispersed and leakage radiation in tomo

  17. CLIC accelerator modules under construction at CERN

    CERN Multimedia

    Anna Pantelia

    2012-01-01

    The Compact LInear Collider (CLIC) study is dedicated to the design of an electron-positron (e- e+) linear accelerator, colliding particle beams at the energy of 3 TeV. The CLIC required luminosity can be reached with powerful particle beams (14 MW each) colliding with extremely small dimensions and high beam stability at the interaction point. The accelerated particle beams must have dimensions of 45 nm in the horizontal plane and 1 nm in the vertical plane. CLIC relies upon a novel two-beam acceleration concept in which the Radio Frequency (RF) power is extracted from a low energy but high-intensity particle beam, called Drive Beam (DB), and transferred to a parallel high energy accelerating particle beam, called Main Beam (MB). The extraction and transfer of the RF power is achieved by the Power Extraction and Transfer Structures (PETS) and the particle beam acceleration is achieved with high precision RF-Accelerating Structures (AS), operating at 11.9942 GHz with an accelerating gradient of 100 MV/m, whi...

  18. Tunnel radio communications system at Stanford Linear Accelerator Center

    Energy Technology Data Exchange (ETDEWEB)

    Struven, W.C.

    1980-07-01

    A unique single frequency, dual daisy chain tunnel radio communication system has been developed for use in our new Po