Download or read book Dose Measurements of Bremsstrahlung Produced Neutrons at the Advanced Photon Source written by and published by . This book was released on 1998 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bremsstrahlung is generated in the storage rings of the synchrotron radiation facilities by the radiative interaction of the circulating particle beam with both the residual gas molecules and storage ring components. These bremsstrahlung photons, having an energy range of zero to the maximum energy of the particle beam, interact with beamline components like beam stops and collimators generating photoneutrons of varying energies. There are three main processes by which photoneutrons may be produced by the high energy bremsstrahlung photons: giant nuclear dipole resonance and decay (10 MeV E{sub {gamma}} 30 MeV), quasi-deuteron production and decay (50 MeV

Download or read book Dose Measurements of Bremsstrahlung produced Neutrons from Thick Targets at the Advanced Photon Source written by and published by . This book was released on 1998 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bremsstrahlung is produced in the Advanced Photon Source storage ring when the positron beam interacts with the storage-ring components or with the residual gas molecules in the storage-ring vacuum. This bremsstrahlung has an energy range of zero to 7.0 GeV, which is the maximum energy of the positron beam. Bremsstrahlung photons of sufficient high energy can interact with beamline components such as beam stops and collimators, generating neutrons of varying energies. This paper presents the results of simultaneous measurements, conducted at the Advanced Photon Source, of bremsstrahlung and the corresponding photoneutron production from thick targets of iron, copper, tungsten and lead, which allow one to correlate photoneutron dose rates from these metals as a function of bremsstrahlung power. The average photoneutron dose equivalent rates, normalized to the bremsstrahlung power, are measured as 2.7 " 0.5 rem/h/W for iron, 3.2 " 0.5 rem/h/W for copper, 3.9 " 0.5 rem/h/W for tungsten, and 4.6 " 0.8 rem/h/W for lead targets. These are measured at 80 cm lateral from the center of the targets, perpendicular to the photon beam direction.

Download or read book The Photoneutron Yield Predictions by PICA and Comparison with the Measurements written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The photoneutron yields at higher photon energies have become very important since the advent of high energy electron accelerators. Bremsstrahlung is produced when the particle beam interacts with the storage-ring components or residual-gas molecules in the storage-ring vacuum. Bremsstrahlung thus produced interacts with the high-Z materials in the beamline like the beam dumps and collimators to produce photoneutrons. There are three modes of neutron production by bremsstrahlung. At low energies ([>=]525 MeV), photons are absorbed by the dipole interaction and the compound nucleus thus formed decays emitting protons and neutrons and other heavier particles. At higher energies ([>=]25 MeV), photon interacts with the nucleus through absorption on a quasi-deuteron, which subsequently decays producing a neutron and proton pair which can interact with the rest of the nucleus. At still higher energies the photopion production becomes possible and competes with the quasi-deuteron process. In this paper we have calculated the photoneutron yield from a thick copper target using the photonuclear interaction code PICA. Using this as the neutron source, we have calculated the dose rates through heavy concrete and compared it with the measurements made at the Advanced Photon Source at Argonne National Lab.

Download or read book Dose Calculations Using MARS for Bremsstrahlung Beam Stops and Collimators in APS Beamline Stations written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Monte Carlo radiation transport code MARS is used to model the generation of gas bremsstrahlung (GB) radiation from 7-GeV electrons which scatter from residual gas atoms in undulator straight sections within the Advanced Photon Source (APS) storage ring. Additionally, MARS is employed to model the interactions of the GB radiation with components along the x-ray beamlines and then determine the expected radiation dose-rates that result. In this manner, MARS can be used to assess the adequacy of existing shielding or the specifications for new shielding when required. The GB radiation generated in the 'thin-target' of an ID straight section will consist only of photons in a 1/E-distribution up to the full energy of the stored electron beam. Using this analytical model, the predicted GB power for a typical APS 15.38-m insertion device (ID) straight section is 4.59 x 10−7 W/nTorr/mA, assuming a background gas composed of air (Z{sub eff} = 7.31) at room temperature (293K). The total GB power provides a useful benchmark for comparisons between analytical and numerical approaches. We find good agreement between MARS and analytical estimates for total GB power. The extended straight section 'target' creates a radial profile of GB, which is highly peaked centered on the electron beam. The GB distribution reflects the size of the electron beam that creates the radiation. Optimizing the performance of MARS in terms of CPU time per incident trajectory requires the use of a relatively short, high-density gas target (air); in this report, the target density is [rho]L = 2.89 x 10−2 g/cm2 over a length of 24 cm. MARS results are compared with the contact dose levels reported in TB-20, which used EGS4 for radiation transport simulations. Maximum dose-rates in 1 cc of tissue phantom form the initial basis for comparison. MARS and EGS4 results are approximately the same for maximum 1-cc dose-rates and attenuation in the photon-dominated regions; for thicker targets, however, the dose-rate no longer depends only on photon attenuation, as photoneutrons (PNs) begin to dominate. The GB radiation-induced photoneutron measurements from four different metals (Fe, Cu, W, and Pb) are compared with MARS predictions. The simulated dose-rates for beamline 6-ID are approximately 3-5 times larger than the measured values, whereas those for beamline 11-ID are much closer. Given the uncertainty in local values of pressure and Z, the degree of agreement between MARS and the PN measurements is good. MARS simulations of GB-induced radiation in and around the FOE show the importance of using actual pressure and gas composition (Z{sub eff}) to obtain accurate PN dose. For a beam current of 300 mA, extrapolating pressure data measured in previously published studies predicts an average background gas pressure of 27 nTorr. An average atomic number of Z{sub eff} = 4.0 is obtained from the same studies. In addition, models of copper masks presently in use at the APS are included. Simulations show that inclusion of exit masks make significant differences in both the radiation spatial distribution within the FOE, as well as the peak intensity. Two studies have been conducted with MARS to assess shielding requirements. First, dose levels in contact with the outside wall of the FOE are examined when GB radiation strikes Pb or W beam stops of varying transverse size within the FOE. Four separate phantom regions are utilized to measure the dose, two at beam elevation and two at the horizontal beam position. The first two phantoms are used for scoring FOE dose along the outside and back walls, horizontally; the second two collect dose on the roof and vertically on the back wall. In all cases, the beam stop depth is maintained at 30 cm. Inclusion of front end (FE) exit masks typically cause a 1-2 order-of-magnitude increase in the dose-rates relative to the case with no masks. Masks place secondary bremsstrahlung sources inside the FOE, and therefore they must be shielded appropriately. The MARS model does not fully account for all shielding present in the hutches; localized shielding is employed in individual hutches. Typically, a collimator, placed downstream of the FE exit masks, mitigates the possible increase in dose. Regarding beam stop transverse size, a modest reduction in dose on the back wall is noted as the stop dimension (square cross section) is increased from 12 cm to 24 cm. In the second study, the thickness of Pb required to shield against the GB extremal ray is determined. In this study, we are interested in finding the thickness of material necessary to add at the edge of a stop to adequately block GB radiation; therefore, we look at the case of no masks in order to have a well-defined GB beam edge. Simulations show the separation between the extremal ray and the edge of the shielding should be 2R{sub m}, where R{sub m} is the Moliere radius.

Download or read book Neutron proton Bremsstrahlung Inclusive Photon Measurements from 100 to 280 MeV written by Douglas Ray Mayo and published by . This book was released on 1997 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings of the Specialists Meeting on Shielding Aspects of Accelerators Targets and Irradiation Facilities written by and published by . This book was released on 1999 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dosimetry Measurements of X ray and Neutron Radiation Levels Near the Shuttle and End Beam Dump at the Advanced Test Accelerator written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Electron beams as a source of directed energy are under study at the Lawrence Livermore National Laboratory (LLNL). An intense 10-kA, 50-MeV, 50-ns full-width half-maximum, pulsed electron beam is generated by the prototype Advanced Test Accelerator (ATA) at the Laboratory's Site 300. Whenever the electron beam is stopped in materials, intense radiation is generated. Estimates based on available data in the literature show that for materials such as lead, photon radiation (x ray, gamma, bremsstrahlung) levels can be as large as 104 roentgens per pulse at 1 m in the zero-degree direction (i.e., the electron-beam direction). Neutrons, which are emitted isotropically, are produced at a level of 1013 n/m2 per pulse. Depending upon the number of pulses and the shielding geometry, the accumulated dose is potentially lethal to personnel and potentially damaging to instrumentation that may be used for diagnostics. To provide shielding for minimizing the risk of exposure to personnel and radiation damage to instrumentation, it is important to determine the x-ray and neutron radiation environment near beamline components such as the beam shuttle dump and beam stop. Photon and neutron dosimetry measurements were performed around the beam shuttle dump on January 9, 1985, and near the carbon beam stop at the end of the beamline before the entrance to the diagnostic tunnel on April 12 and December 23, 1985. These measurements together with simple rule-of-thumb estimates and Monte Carlo electron-photon shower calculations of the absorbed dose are presented in this report. 17 refs., 14 figs., 13 tabs.

Download or read book Active Interrogation in Nuclear Security written by Igor Jovanovic and published by Springer. This book was released on 2018-06-07 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume constitutes the state-of-the-art in active interrogation, widely recognized as indispensable methods for addressing current and future nuclear security needs. Written by a leading group of science and technology experts, this comprehensive reference presents technologies and systems in the context of the fundamental physics challenges and practical requirements. It compares the features, limitations, technologies, and impact of passive and active measurement techniques; describes radiation sources for active interrogation including electron and ion accelerators, intense lasers, and radioisotope-based sources; and it describes radiation detectors used for active interrogation. Entire chapters are devoted to data acquisition and processing systems, modeling and simulation, data interpretation and algorithms, and a survey of working active measurement systems. Active Interrogation in Nuclear Security is structured to appeal to a range of audiences, including graduate students, active researchers in the field, and policy analysts. The first book devoted entirely to active interrogation Presents a focused review of the relevant physics Surveys available technology Analyzes scientific and technology trends Provides historical and policy context Igor Jovanovic is a Professor of Nuclear Engineering and Radiological Sciences at the University of Michigan and has previously also taught at Penn State University and Purdue University. He received his Ph.D. from University of California, Berkeley and worked as physicist at Lawrence Livermore National Laboratory. Dr. Jovanovic has made numerous contributions to the science and technology of radiation detection, as well as the radiation sources for use in active interrogation in nuclear security. He has taught numerous undergraduate and graduate courses in areas that include radiation detection, nuclear physics, and nuclear security. At University of Michigan Dr. Jovanovic is the director of Neutron Science Laboratory and is also associated with the Center for Ultrafast Optical Science. Anna Erickson is an Assistant Professor in the Nuclear and Radiological Engineering Program of the G.W. Woodruff School of Mechanical Engineering at Georgia Institute of Technology. Previously, she was a postdoctoral researcher in the Advanced Detectors Group at Lawrence Livermore National Laboratory. Dr. Erickson received her PhD from Massachusetts Institute of Technology with a focus on radiation detection for active interrogation applications. Her research interests focus on nuclear non-proliferation including antineutrino analysis and non-traditional detector design and characterization. She teaches courses in advanced experimental detection for reactor and nuclear nonproliferation applications, radiation dosimetry and fast reactor analysis.

Download or read book Proton Therapy Physics written by Harald Paganetti and published by CRC Press. This book was released on 2016-04-19 with total page 691 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proton Therapy Physics goes beyond current books on proton therapy to provide an in-depth overview of the physics aspects of this radiation therapy modality, eliminating the need to dig through information scattered in the medical physics literature. After tracing the history of proton therapy, the book summarizes the atomic and nuclear physics background necessary for understanding proton interactions with tissue. It describes the physics of proton accelerators, the parameters of clinical proton beams, and the mechanisms to generate a conformal dose distribution in a patient. The text then covers detector systems and measuring techniques for reference dosimetry, outlines basic quality assurance and commissioning guidelines, and gives examples of Monte Carlo simulations in proton therapy. The book moves on to discussions of treatment planning for single- and multiple-field uniform doses, dose calculation concepts and algorithms, and precision and uncertainties for nonmoving and moving targets. It also examines computerized treatment plan optimization, methods for in vivo dose or beam range verification, the safety of patients and operating personnel, and the biological implications of using protons from a physics perspective. The final chapter illustrates the use of risk models for common tissue complications in treatment optimization. Along with exploring quality assurance issues and biological considerations, this practical guide collects the latest clinical studies on the use of protons in treatment planning and radiation monitoring. Suitable for both newcomers in medical physics and more seasoned specialists in radiation oncology, the book helps readers understand the uncertainties and limitations of precisely shaped dose distribution.

Download or read book Accelerator Radiation Protection written by G. R. Stevenson and published by . This book was released on 2001 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Accelerator Radiation Physics for Personnel and Environmental Protection written by J. Donald Cossairt and published by CRC Press. This book was released on 2019-05-06 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: Choice Recommended Title, January 2020 Providing a vital resource in tune with the massive advancements in accelerator technologies that have taken place over the past 50 years, Accelerator Radiation Physics for Personnel and Environmental Protection is a comprehensive reference for accelerator designers, operators, managers, health and safety staff, and governmental regulators. Up-to-date with the latest developments in the field, it allows readers to effectively work together to ensure radiation safety for workers, to protect the environment, and adhere to all applicable standards and regulations. This book will also be of interest to graduate and advanced undergraduate students in physics and engineering who are studying accelerator physics. Features: Explores accelerator radiation physics and the latest results and research in a comprehensive single volume, fulfilling a need in the market for an up-to-date book on this topic Contains problems designed to enhance learning Addresses undergraduates with a background in math and/or science

Download or read book Proceedings of the Second Specialists Meeting on Shielding Aspects of Accelerators Targets and Irradiation Facilities written by OECD Nuclear Energy Agency and published by OECD. This book was released on 1996 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1992 with total page 1572 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA Scientific and Technical Reports written by United States. National Aeronautics and Space Administration Scientific and Technical Information Division and published by . This book was released on 1967 with total page 2300 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Photon Electron Proton and Neutron Interaction Data for Body Tissues written by and published by International Commission on Radiation. This book was released on 1992-01-01 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings written by and published by . This book was released on 1995 with total page 788 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synchrotron Radiation Instrumentation written by Ernest Fontes and published by A I P Press. This book was released on 1997 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Tenth United States National Conference on Synchrotron Radiation Instrumentation was held June 17-20, 1997 at Cornell University in Ithaca, NY. The SRI National meeting is held every two years, and this year was hosted by CHESS, the Cornell High Energy Synchrotron Source. As a national meeting, it serves as a venue for all light sources in the United States to discuss the latest, most advanced capabilities in the fields of X-ray and VUV synchrotron radiation. Topics for this year's meeting included: Facilities: history, status, and upgrades Sources: insertion devices, laser, excited and other High-tech: beam stabilization, beamline hardware, and control Optics: novel design, fabrication, testing and use Small stuff: making and imaging micro structures Real-time: in-situ measurements and materials characterization Detectors: large, small, fast, and energy-resolving