Sample records for neutron dose reconstruction

  1. Neutron dose equivalent meter

    DOE Patents [OSTI]

    Olsher, Richard H. (Los Alamos, NM); Hsu, Hsiao-Hua (Los Alamos, NM); Casson, William H. (Los Alamos, NM); Vasilik, Dennis G. (Los Alamos, NM); Kleck, Jeffrey H. (Menlo Park, CA); Beverding, Anthony (Foster City, CA)

    1996-01-01T23:59:59.000Z

    A neutron dose equivalent detector for measuring neutron dose capable of accurately responding to neutron energies according to published fluence to dose curves. The neutron dose equivalent meter has an inner sphere of polyethylene, with a middle shell overlying the inner sphere, the middle shell comprising RTV.RTM. silicone (organosiloxane) loaded with boron. An outer shell overlies the middle shell and comprises polyethylene loaded with tungsten. The neutron dose equivalent meter defines a channel through the outer shell, the middle shell, and the inner sphere for accepting a neutron counter tube. The outer shell is loaded with tungsten to provide neutron generation, increasing the neutron dose equivalent meter's response sensitivity above 8 MeV.

  2. Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Finch, S.M.; McMakin, A.H. (comps.)

    1991-01-01T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): Source terms; environmental transport environmental monitoring data; demographics, agriculture, food habits; environmental pathways and dose estimates.

  3. Technical basis for dose reconstruction

    SciTech Connect (OSTI)

    Anspaugh, L.R.

    1996-01-31T23:59:59.000Z

    The purpose of this paper is to consider two general topics: technical considerations of why dose-reconstruction studies should or should not be performed and methods of dose reconstruction. The first topic is of general and growing interest as the number of dose-reconstruction studies increases, and one asks the question whether it is necessary to perform a dose reconstruction for virtually every site at which, for example, the Department of Energy (DOE) has operated a nuclear-related facility. And there is the broader question of how one might logically draw the line at performing or not performing dose-reconstruction (radiological and chemical) studies for virtually every industrial complex in the entire country. The second question is also of general interest. There is no single correct way to perform a dose-reconstruction study, and it is important not to follow blindly a single method to the point that cheaper, faster, more accurate, and more transparent methods might not be developed and applied.

  4. Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Finch, S.M.; McMakin, A.H. (comps.)

    1992-06-01T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is being managed and conducted by the Battelle Pacific Northwest Laboratories under contract with the Centers for Disease Control. The independent Technical Steering Panel (TSP) provides technical direction. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): source terms; environmental transport; environmental monitoring data; demography, food consumption, and agriculture; environmental pathways and dose estimates.

  5. Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    McMakin, A.H.; Cannon, S.D.; Finch, S.M. (comps.)

    1992-07-01T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The TSP consists of experts in environmental pathways, epidemiology, surface-water transport, ground-water transport, statistics, demography, agriculture, meteorology, nuclear engineering, radiation dosimetry, and cultural anthropology. Included are appointed technical members representing the states of Oregon, Washington, and Idaho, a representative of Native American tribes, and an individual representing the public. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impact on humans (dose estimates): Source terms, environmental transport, environmental monitoring data, demography, food consumption, and agriculture, and environmental pathways and dose estimates. Progress is discussed.

  6. Hanford Environmental Dose Reconstruction Project. Monthly report

    SciTech Connect (OSTI)

    Cannon, S.D.; Finch, S.M. [comps.

    1992-10-01T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The independent Technical Steering Panel (TSP) provides technical direction. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impact on humans (dose estimates):Source Terms, Environmental Transport, Environmental Monitoring Data, Demography, Food Consumption, and Agriculture, and Environmental Pathways and Dose Estimates.

  7. Hanford Environmental Dose Reconstruction Project Monthly Report

    SciTech Connect (OSTI)

    Finch, S.M.; McMakin, A.H. (comps.)

    1992-03-01T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): Source Terms, Environmental Transport, Environmental Monitoring Data, Demography, Food Consumption, and Agriculture, and Environmental Pathways and Dose Estimates.

  8. Hanford Environmental Dose Reconstruction Project. Monthly report

    SciTech Connect (OSTI)

    Finch, S.M.; McMakin, A.H. [comps.

    1992-04-01T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): Source terms, environmental transport, environmental monitoring data, demography, food consumption, and agriculture, and environmental pathways and dose estimates.

  9. Hanford Environmental Dose Reconstruction Project Monthly Report

    SciTech Connect (OSTI)

    Finch, S.M. (comp.)

    1990-05-01T23:59:59.000Z

    This monthly report summarizes the technical progress and project status for the Hanford Environmental Dose Reconstruction (HEDR) Project being conducted at Pacific Northwest Laboratory (PNL) under the direction of a Technical Steering Panel (TSP). The TSP is composed of experts in numerous technical fields related to this project and represents the interests of the public. The US Department of Energy (DOE) funds the project. The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These tasks address each of the primary steps in the path from radioactive releases to dose estimates source terms, environmental transport, environmental monitoring data, demographics, agriculture, and food habits, and environmental pathways and dose estimates.

  10. Hanford Environmental Dose Reconstruction Project Monthly Report

    SciTech Connect (OSTI)

    Finch, S.M. (comp.)

    1990-01-01T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that populations could have received from nuclear operations at Hanford since 1944. The project is being managed and conducted by the Pacific Northwest Laboratory (PNL) under the direction of an independent Technical Steering Panel (TSP). The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): source terms; environmental transport; environmental monitoring data; demographics; agriculture; food habits; and environmental pathways and dose estimates. 3 figs.

  11. Population estimates for Phase 1: Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Beck, D.M.; Erickson, A.R.; Harkreader, S.A.

    1992-03-01T23:59:59.000Z

    This report summarizes the population estimates of Phase I of the Hanford Environmental Dose Reconstruction (HEDR) Project. These estimates were used to develop preliminary dose estimates.

  12. Hanford Environmental Dose Reconstruction Project. Monthly report

    SciTech Connect (OSTI)

    McMakin, A.H.; Cannon, S.D.; Finch, S.M. [comps.

    1992-07-01T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The TSP consists of experts in environmental pathways, epidemiology, surface-water transport, ground-water transport, statistics, demography, agriculture, meteorology, nuclear engineering, radiation dosimetry, and cultural anthropology. Included are appointed technical members representing the states of Oregon, Washington, and Idaho, a representative of Native American tribes, and an individual representing the public. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impact on humans (dose estimates): Source terms, environmental transport, environmental monitoring data, demography, food consumption, and agriculture, and environmental pathways and dose estimates. Progress is discussed.

  13. Hanford Environmental Dose Reconstruction Project. Monthly report

    SciTech Connect (OSTI)

    Finch, S. M.; McMakin, A. H.

    1991-09-01T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation dose that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into five technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (i.e., dose estimates). The Source Terms Task develops estimates of radioactive emissions from Hanford facilities since 1944. The Environmental Transport Task reconstructs the movements of radioactive particles from the areas of release to populations. The Environmental Monitoring Data Task assemblies, evaluates and reports historical environmental monitoring data. The Demographics, Agriculture and Food Habits Task develops the data needed to identify the populations that could have been affected by the releases. The Environmental Pathways and Dose Estimates Task used the information derived from the other Tasks to estimate the radiation doses individuals could have received from Hanford radiation. This document lists the progress on this project as of September 1991. 3 figs., 2 tabs.

  14. Dose-equivalent neutron dosimeter

    DOE Patents [OSTI]

    Griffith, R.V.; Hankins, D.E.; Tomasino, L.; Gomaa, M.A.M.

    1981-01-07T23:59:59.000Z

    A neutron dosimeter is disclosed which provides a single measurement indicating the amount of potential biological damage resulting from the neutron exposure of the wearer, for a wide range of neutron energies. The dosimeter includes a detecting sheet of track etch detecting material such as a carbonate plastic, for detecting higher energy neutrons, and a radiator layer contaning conversion material such as /sup 6/Li and /sup 10/B lying adjacent to the detecting sheet for converting moderate energy neutrons to alpha particles that produce tracks in the adjacent detecting sheet.

  15. Hanford Environmental Dose Reconstruction Project monthly report, February 1993

    SciTech Connect (OSTI)

    Cannon, S.D.; Finch, S.M. (comps.)

    1993-01-01T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project Is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impact on humans (dose estimates): Source Terms; Environmental Transport; Environmental Monitoring Data; Demography, Food Consumption, and Agriculture; and Environmental Pathways and Dose Estimates.

  16. Hanford Environmental Dose Reconstruction Project monthly report, February 1993

    SciTech Connect (OSTI)

    Cannon, S.D.; Finch, S.M. [comps.

    1993-03-01T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project Is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impact on humans (dose estimates): Source Terms; Environmental Transport; Environmental Monitoring Data; Demography, Food Consumption, and Agriculture; and Environmental Pathways and Dose Estimates.

  17. Hanford Environmental Dose Reconstruction Project. Monthly report, November 1991

    SciTech Connect (OSTI)

    Finch, S.M.; McMakin, A.H. [comps.

    1991-12-31T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): Source terms; environmental transport environmental monitoring data; demographics, agriculture, food habits; environmental pathways and dose estimates.

  18. Hanford Environmental Dose Reconstruction Project monthly report, May 1992

    SciTech Connect (OSTI)

    Finch, S.M.; McMakin, A.H. [comps.

    1992-08-01T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These task correspond to the path radionuclides followed, from release to impact on humans (dose estimates): Source terms, environmental transport, environmental monitoring data, demography, food consumption, and agriculture, and environmental pathways and dose estimates.

  19. Hanford Environmental Dose Reconstruction Project monthly report, May 1992

    SciTech Connect (OSTI)

    Finch, S.M.; McMakin, A.H. (comps.)

    1992-01-01T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These task correspond to the path radionuclides followed, from release to impact on humans (dose estimates): Source terms, environmental transport, environmental monitoring data, demography, food consumption, and agriculture, and environmental pathways and dose estimates.

  20. Hanford Environmental Dose Reconstruction Project. Monthly report, June 1992

    SciTech Connect (OSTI)

    Finch, S.M.; McMakin, A.H. [comps.

    1992-06-01T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is being managed and conducted by the Battelle Pacific Northwest Laboratories under contract with the Centers for Disease Control. The independent Technical Steering Panel (TSP) provides technical direction. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): source terms; environmental transport; environmental monitoring data; demography, food consumption, and agriculture; environmental pathways and dose estimates.

  1. Phase 1 of the Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Not Available

    1991-08-01T23:59:59.000Z

    The work described in this report was prompted by the public's concern about potential effect from the radioactive materials released from the Hanford Site. The Hanford Environmental Dose Reconstruction (HEDR) Project was established to estimate radiation dose the public might have received from the Hanford Site since 1944, when facilities began operating. Phase 1 of the HEDR Project is a pilot'' or demonstration'' phase. The objectives of this initial phase were to determine whether enough historical information could be found or reconstructed to be used for dose estimation and develop and test conceptual and computational models for calculating credible dose estimates. Preliminary estimates of radiation doses were produced in Phase 1 because they are needed to achieve these objectives. The reader is cautioned that the dose estimates provided in this and other Phase 1 HEDR reports are preliminary. As the HEDR Project continues, the dose estimates will change for at least three reasons: more complete input information for models will be developed; the models themselves will be refined; and the size and shape of the geographic study area will change. This is one of three draft reports that summarize the first phase of the four-phased HEDR Project. This, the Summary Report, is directed to readers who want a general understanding of the Phase 1 work and preliminary dose estimates. The two other reports -- the Air Pathway Report and the Columbia River Pathway Report -- are for readers who understand the radiation dose assessment process and want to see more technical detail. Detailed descriptions of the dose reconstruction process are available in more than 20 supporting reports listed in Appendix A. 32 refs., 46 figs.

  2. Overview of the Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Shipler, D.B.; Napier, B.A.; Ikenberry, T.A.

    1992-04-01T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that specific and representative individuals and populations may have received as a result of releases of radioactive materials from historical operations at the Hanford Site. These dose estimates would account for the uncertainties of information regarding facilities operations, environmental monitoring, demography, food consumption and lifestyles, and the variability of natural phenomena. Other objectives of the HEDR Project include: supporting the Hanford Thyroid Disease Study (HTDS), declassifying Hanford-generated information and making it available to the public, performing high-quality, credible science, and conducting the project in an open, public forum. The project is briefly described.

  3. Phase 1 of the Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Not Available

    1990-07-20T23:59:59.000Z

    For more than 40 years, the US government made plutonium for nuclear weapons at the Hanford Site in southeastern Washington State. Radioactive materials were released to both the air and water from Hanford. People could have been exposed to these materials, called radionuclides. The Hanford Environmental Dose Reconstruction (HEDR) Project is a multi-year scientific study to estimate the radiation doses the public may have received as a results of these releases. The study began in 1988. During the first phase, scientists began to develop and test methods for reconstructing the radiation doses. To do this, scientists found or reconstructed information about the amount and type of radionuclides that were released from Hadford facilities, where they traveled in environment, and how they reached people. Information about the people who could have been exposed was also found or reconstructed. Scientists then developed a computer model that can estimate doses from radiation exposure received many years ago. All the information that had been gathered was fed into the computer model. Then scientists did a test run'' to see whether the model was working properly. As part of its test run,'' scientists asked the computer model to generate two types of preliminary results: amounts of radionuclides in the environment (air, soil, pasture grass, food, and milk) and preliminary doses people could have received from all the routes of radiation exposure, called exposure pathways. Preliminary dose estimates were made for categories of people who shared certain characteristics and for the Phase 1 population as a whole. 26 refs., 48 figs.

  4. Population exposure dose reconstruction for the Urals Region

    SciTech Connect (OSTI)

    Degteva, M.O.; Kozheurov, V.P.; Vorobiova, M.I.; Burmistrov, D.S. [Urals Research Center for Radiation Medicine, Chelyabinsk (Russian Federation); Khokhryakov, V.V. [Mayak Production Assn., Ozyorsk (Russian Federation); Suslova, K.G. [Moscow Biophysics Inst., Ozyorsk (Russian Federation); Anspaugh, L.R. [Lawrence Livermore National Lab., CA (United States); Napier, B.A. [Pacific Northwest Lab., Richland, WA (United States); Bouville, A. [National Cancer Inst., Bethesda, MD (United States)

    1996-06-01T23:59:59.000Z

    This presentation describes the first preliminary results of an ongoing joint Russian-US pilot feasibility study. Many people participated in workshops to determine what Russian and United States scientists could do together in the area of dose reconstruction in the Urals population. Most of the results presented here came from a joint work shop in St. Petersburg, Russia (11-13 July 1995). The Russians at the workshop represented the Urals Research Center for Radiation Medicine (URCRM), the Mayak Industrial Association, and Branch One of the Moscow Biophysics Institute. The US Collaborators were Dr. Anspaugh of LLNL, Dr. Nippier of PNL, and Dr. Bouville of the National Cancer Institute. The objective of the first year of collaboration was to look at the source term and levels of radiation contamination, the historical data available, and the results of previous work carried out by Russian scientists, and to determine a conceptual model for dose reconstruction.

  5. Estimation of food consumption. Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Callaway, J.M. Jr.

    1992-04-01T23:59:59.000Z

    The research reported in this document was conducted as a part of the Hanford Environmental Dose Reconstruction (HEDR) Project. The objective of the HEDR Project is to estimate the radiation doses that people could have received from operations at the Hanford Site. Information required to estimate these doses includes estimates of the amounts of potentially contaminated foods that individuals in the region consumed during the study period. In that general framework, the objective of the Food Consumption Task was to develop a capability to provide information about the parameters of the distribution(s) of daily food consumption for representative groups in the population for selected years during the study period. This report describes the methods and data used to estimate food consumption and presents the results developed for Phase I of the HEDR Project.

  6. Ground-water contribution to dose from past Hanford Operations. Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Freshley, M.D.; Thorne, P.D.

    1992-08-01T23:59:59.000Z

    The Hanford Environmental Dose Reconstruction (HEDR) Project is being conducted to estimate radiation doses that populations and individuals could have received from Hanford Site operations from 1944 to the present. Four possible pathways by which radionuclides migrating in ground water on the Hanford Site could have reached the public have been identified: (1) through contaminated ground water migrating to the Columbia River; (2) through wells on or adjacent to the Hanford Site; (3) through wells next to the Columbia River downstream of Hanford that draw some or all of their water from the river (riparian wells); and (4) through atmospheric deposition resulting in contamination of a small watershed that, in turn, results in contamination of a shallow well or spring by transport in the ground water. These four pathways make up the ``ground-water pathway,`` which is the subject of this study. Assessment of the ground-water pathway was performed by (1) reviewing the existing extensive literature on ground water and ground-water monitoring at Hanford and (2) performing calculations to estimate radionuclide concentrations where no monitoring data were collected. Radiation doses that would result from exposure to these radionuclides were calculated.

  7. Hanford Environmental Dose Reconstruction Project, Quarterly report, September--November 1993

    SciTech Connect (OSTI)

    Cannon, S.D.; Finch, S.M. [comps.

    1993-12-31T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impact on humans (dose estimates); Source Terms, Environmental Transport, Environmental Monitoring Data, Demography, Food Consumption, and Agriculture, and Environmental Pathways and Dose Estimates.

  8. Hanford Environmental Dose Reconstruction Project. Quarterly report, June--August 1993

    SciTech Connect (OSTI)

    Cannon, S.D.; Finch, S.M. [comps.

    1993-10-01T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impact on humans (dose estimates): Source Terms, Environmental Transport, Environmental Monitoring Data, Demography, Food Consumption, and Agriculture, and Environmental Pathways and Dose Estimates.

  9. Quantifying the Impact of Immediate Reconstruction in Postmastectomy Radiation: A Large, Dose-Volume Histogram-Based Analysis

    SciTech Connect (OSTI)

    Ohri, Nisha [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Cordeiro, Peter G. [Department of Plastic Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Plastic Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Keam, Jennifer [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Ballangrud, Ase [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Shi Weiji; Zhang Zhigang [Department of Biostatistics and Epidemiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Biostatistics and Epidemiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Nerbun, Claire T.; Woch, Katherine M.; Stein, Nicholas F.; Zhou Ying [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); McCormick, Beryl; Powell, Simon N. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Ho, Alice Y., E-mail: HoA1234@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

    2012-10-01T23:59:59.000Z

    Purpose: To assess the impact of immediate breast reconstruction on postmastectomy radiation (PMRT) using dose-volume histogram (DVH) data. Methods and Materials: Two hundred forty-seven women underwent PMRT at our center, 196 with implant reconstruction and 51 without reconstruction. Patients with reconstruction were treated with tangential photons, and patients without reconstruction were treated with en-face electron fields and customized bolus. Twenty percent of patients received internal mammary node (IMN) treatment. The DVH data were compared between groups. Ipsilateral lung parameters included V20 (% volume receiving 20 Gy), V40 (% volume receiving 40 Gy), mean dose, and maximum dose. Heart parameters included V25 (% volume receiving 25 Gy), mean dose, and maximum dose. IMN coverage was assessed when applicable. Chest wall coverage was assessed in patients with reconstruction. Propensity-matched analysis adjusted for potential confounders of laterality and IMN treatment. Results: Reconstruction was associated with lower lung V20, mean dose, and maximum dose compared with no reconstruction (all P<.0001). These associations persisted on propensity-matched analysis (all P<.0001). Heart doses were similar between groups (P=NS). Ninety percent of patients with reconstruction had excellent chest wall coverage (D95 >98%). IMN coverage was superior in patients with reconstruction (D95 >92.0 vs 75.7%, P<.001). IMN treatment significantly increased lung and heart parameters in patients with reconstruction (all P<.05) but minimally affected those without reconstruction (all P>.05). Among IMN-treated patients, only lower lung V20 in those without reconstruction persisted (P=.022), and mean and maximum heart doses were higher than in patients without reconstruction (P=.006, P=.015, respectively). Conclusions: Implant reconstruction does not compromise the technical quality of PMRT when the IMNs are untreated. Treatment technique, not reconstruction, is the primary determinant of target coverage and normal tissue doses.

  10. Neutron field reconstruction with consideration of the spatial correlation of the cross-section value error

    SciTech Connect (OSTI)

    Semyonov, A. A.; Druzhaev, A. A., E-mail: andreydruzhaev@gmail.com; Schukin, N. V. [National Research Nuclear University MEPhI (Russian Federation)

    2014-12-15T23:59:59.000Z

    A method for reconstructing the neutron field in a reactor with consideration of the spatial correlation of the cross-section value error was analyzed. It was shown that this method is more accurate than the classical approach to reconstruction. An efficient way of using this technique was proposed. The efficiency for the RBMK critical test facility was estimated.

  11. FY 1992 revised task plans for the Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Shipler, D.B.

    1992-04-01T23:59:59.000Z

    The purpose of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate radiation doses from Hanford Site operations since 1944 to populations and individuals. The primary objectives of work to be performed in FY 1992 is to determine the appropriate scope (space, time, and radionuclides, pathways and individuals/population groups) and accuracy (level of uncertainty in dose estimates) for the project. Another objective is to use a refined computer model to estimate Native American tribal doses and individual doses for the Hanford Thyroid Disease Study (HTDS). Project scope and accuracy requirements defined in FY 1992 can translated into model and data requirements that must be satisfied during FY 1993.

  12. FY 1992 revised task plans for the Hanford Environmental Dose Reconstruction Project. Revision 1

    SciTech Connect (OSTI)

    Shipler, D.B.

    1992-04-01T23:59:59.000Z

    The purpose of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate radiation doses from Hanford Site operations since 1944 to populations and individuals. The primary objectives of work to be performed in FY 1992 is to determine the appropriate scope (space, time, and radionuclides, pathways and individuals/population groups) and accuracy (level of uncertainty in dose estimates) for the project. Another objective is to use a refined computer model to estimate Native American tribal doses and individual doses for the Hanford Thyroid Disease Study (HTDS). Project scope and accuracy requirements defined in FY 1992 can translated into model and data requirements that must be satisfied during FY 1993.

  13. An external dose reconstruction involving a radiological dispersal device

    E-Print Network [OSTI]

    Hearnsberger, David Wayne

    2007-04-25T23:59:59.000Z

    phantom compared favorably to the derived organ absorbed doses measured by the Panasonic thermoluminescence dosimeters and with Monte Carlo �N� Particle modeled results. Additionally, a Victoreen 450P pressurized ion chamber measured...

  14. INTEGRATED CODES FOR ESTIMATING ENVIRONMENTAL ACCUMULATION ANd INDIVIDUAL DOSE FROM PAST HANFORD ATMOSPHERIC RELEASES Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Ikenberry, T. A.; Burnett, R. A.; Napier, B. A.; Reitz, N. A.; Shipler, D. B.

    1992-02-01T23:59:59.000Z

    Preliminary radiation doses were estimated and reported during Phase I of the Hanford Environmental Dose Reconstruction (HEDR) Project. As the project has progressed, additional information regarding the magnitude and timing of past radioactive releases has been developed, and the general scope of the required calculations has been enhanced. The overall HEDR computational model for computing doses attributable to atmospheric releases from Hanford Site operations is called HEDRIC (Hanford Environmental Dose Reconstruction Integrated Codes). It consists of four interrelated models: source term, atmospheric transport, environmental accumulation, and individual dose. The source term and atmospheric transport models are documented elsewhere. This report describes the initial implementation of the design specifications for the environmental accumulation model and computer code, called DESCARTES (Dynamic EStimates of Concentrations and Accumulated Radionuclides in Terrestrial Environments), and the individual dose model and computer code, called CIDER (Calculation of Individual Doses from Environmental Radionuclides). The computations required of these models and the design specifications for their codes were documented in Napier et al. (1992). Revisions to the original specifications and the basis for modeling decisions are explained. This report is not the final code documentation but gives the status of the model and code development to date. Final code documentation is scheduled to be completed in FY 1994 following additional code upgrades and refinements. The user's guide included in this report describes the operation of the environmental accumulation and individual dose codes and associated pre- and post-processor programs. A programmer's guide describes the logical structure of the programs and their input and output files.

  15. Uncertainty and Sensitivity Analyses Plan. Draft for Peer Review: Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Simpson, J.C.; Ramsdell, J.V. Jr.

    1993-04-01T23:59:59.000Z

    Hanford Environmental Dose Reconstruction (HEDR) Project staff are developing mathematical models to be used to estimate the radiation dose that individuals may have received as a result of emissions since 1944 from the US Department of Energy`s (DOE) Hanford Site near Richland, Washington. An uncertainty and sensitivity analyses plan is essential to understand and interpret the predictions from these mathematical models. This is especially true in the case of the HEDR models where the values of many parameters are unknown. This plan gives a thorough documentation of the uncertainty and hierarchical sensitivity analysis methods recommended for use on all HEDR mathematical models. The documentation includes both technical definitions and examples. In addition, an extensive demonstration of the uncertainty and sensitivity analysis process is provided using actual results from the Hanford Environmental Dose Reconstruction Integrated Codes (HEDRIC). This demonstration shows how the approaches used in the recommended plan can be adapted for all dose predictions in the HEDR Project.

  16. Environmental Radiation Dose Reconstruction for U.S. and Russian Weapons Production Facilities: Hanford and Mayak

    SciTech Connect (OSTI)

    Ansbaugh, Lynn R.; Degteva, M. O.; Kozheurov, V. P.; Napier, Bruce A.; Tolstykh, E. I.; Vorobiova, M. I.

    2003-05-01T23:59:59.000Z

    Another way to look at Cold War legacies is to examine the major environmental releases that resulted from past operation of Cold War-related facilities for the manufacture of nuclear weapons. Examining these historical releases and the resultant radiation dose to individuals living near these facilities is called environmental dose reconstruction. Dose reconstructions have been performed or are underway at most large Cold War installations in the United States, such as the Hanford facility; several are also underway in other countries, such as at the Mayak facility in Russia. The efforts in the United States are mostly based on historical operating records and current conditions, which are used to estimate environmental releases, transport, and human exposure. The Russian efforts are largely based on environmental measurements and measurements of human subjects; environmental transport modelling, when conducted, is used to organize and validate the measurements. Past operation of Cold War-related facilities for the manufacture of nuclear weapons has resulted in major releases of radionuclides into the environment. Reconstruction of the historical releases and the resultant radiation dose to individuals in the public living near these facilities is called environmental dose reconstruction. Dose reconstructions have been performed or are underway at most large Cold War installations in the United States; several are also underway in other countries. The types of activity performed, the operating histories, and the radionuclide releases vary widely across the different facilities. The U.S. Hanford Site and the Russian Mayak Production Association are used here to illustrate the nature of the assessed problems and the range of approaches developed to solve them.

  17. Columbia River pathway report: phase I of the Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Not Available

    1991-07-01T23:59:59.000Z

    This report summarizes the river-pathway portion of the first phase of the Hanford Environmental Dose Reconstruction (HEDR) Project. The HEDR Project is estimating radiation doses that could have been received by the public from the Department of Energy's Hanford Site, in southeastern Washington State. Phase 1 of the river-pathway dose reconstruction effort sought to determine whether dose estimates could be calculated for populations in the area from above the Hanford Site at Priest Rapids Dam to below the site at McNary Dam from January 1964 to December 1966. Of the potential sources of radionuclides from the river, fish consumption was the most important. Doses from drinking water were lower at Pasco than at Richland and lower at Kennewick than at Pasco. The median values of preliminary dose estimates calculated by HEDR are similar to independent, previously published estimates of average doses to Richland residents. Later phases of the HEDR Project will address dose estimates for periods other than 1964--1966 and for populations downstream of McNary Dam. 17 refs., 19 figs., 1 tab.

  18. United States-assisted studies on dose reconstruction in the former Soviet Union

    SciTech Connect (OSTI)

    Anspaugh, L.R. [Lawrence Livermore National Lab., CA (United States); Bouville, A. [National Cancer Institute, Rockville, MD (United States)

    1995-12-01T23:59:59.000Z

    Following the Chernobyl accident, the US and the USSR entered into an agreement to work on the safety of civilian nuclear reactors; one aspect of that work was to study the environmental transport and health effects of radionuclides released by the accident. After the break-up of the USSR separate agreements were established between the US and Ukraine, Belarus, and Russia to continue work on dose reconstruction and epidemiologic studies of health effects from exposure to external radiation and the incorporation of radionuclides. Studies in Belarus and Ukraine related to the Chernobyl accident now emphasize epidemiologic: studies of childhood-thyroid cancer and leukemia, and eye-lens-cataract formation in liquidators. Supporting studies on dose reconstruction emphasize a variety of ecological, physical, and biological techniques. Studies being conducted in Russia currently emphasize health effects in the workers and the population around the Mayak Industrial Association. As this production complex is an analogue of the US Hanford Works, advantage is being taken of the US experience in conducting a similar, recently completed dose-reconstruction study. In all cases the primary work on dose reconstruction is being performed by scientists from the former Soviet Union. US assistance is in the form of expert consultation and participation, exchange visits, provision of supplies and equipment, and other forms of local assistance.

  19. X-band EPR imaging as a tool for gradient dose reconstruction in irradiated bones

    SciTech Connect (OSTI)

    Leveque, Philippe; Godechal, Quentin; Bol, Anne; Trompier, Francois; Gallez, Bernard [Biomedical Magnetic Resonance Unit, Universite catholique de Louvain, B-1200 Brussels (Belgium); Molecular Imaging and Experimental Radiotherapy Unit, Universite catholique de Louvain, B-1200 Brussels (Belgium); Institut de Surete Nucleaire et de Radioprotection, F-92262 Fontenay-aux-Roses (France); Biomedical Magnetic Resonance Unit, Universite catholique de Louvain, B-1200 Brussels (Belgium)

    2009-09-15T23:59:59.000Z

    Purpose: Various tools are currently available for dose reconstruction in individuals after accidental exposure to ionizing radiation. Among the available biological analyses, Monte Carlo simulations, and biophysical methods, such as electron paramagnetic resonance (EPR), the latter has proved its usefulness for retrospective dosimetry. Although EPR spectroscopy is probably the most sensitive technique, it does not provide spatial dosimetric data. This information is, however, highly desirable when steep dose gradient irradiations are involved. The purpose of this work was to explore the possibilities of EPR imaging (EPRI) for spatial dose reconstruction in irradiated biological material. Methods: X-band EPRI was used to reconstruct ex vivo the relative dose distribution in human bone samples and hydroxyapatite phantoms after irradiation with brachytherapy seeds or x rays. Three situations were investigated: Homogeneous, stepwise gradient, and continuous gradient irradiation. Results: EPRI gave a faithful relative spin density distribution in bone samples and in hydroxyapatite phantoms. Measured dose ratios were in close agreement with the actual delivered dose ratios. EPRI was able to distinguish the dose gradients induced by two different sources ({sup 125}I and {sup 192}Ir). However, the measured spatial resolution of the system was 1.9 mm and this appeared to be a limiting factor. The method could be improved by using new signal postprocessing strategies. Conclusions: This study demonstrates that EPRI can be used to assess the regional relative dose distribution in irradiated bone samples. The method is currently applicable to ex vivo measurements of small size samples with low variation in tissue density but is likely to be adapted for in vivo application using L-band EPRI.

  20. Draft Air Pathway Report: Phase 1 of the Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Not Available

    1990-07-20T23:59:59.000Z

    This report summarizes the air pathway portion of the first phase of the Hanford Environmental Dose Reconstruction (HEDR) Project, conducted by Battelle staff at the Pacific Northwest Laboratory under the direction of an independent Technical Steering Panel. The HEDR Project is estimating historical radiation doses that could have been received by populations near the Department of Energy's Hanford Site, in southeastern Washington State. Phase 1 of the air-pathway dose reconstruction sought to determine whether dose estimates could be calculated for populations in the 10 counties nearest the Hanford Site from atmospheric releases of iodine-131 from the site from 1944--1947. Phase 1 demonstrated the following: HEDR-calculated source-term estimates of iodine-131 releases to the atmosphere were within 20% of previously published estimates; calculated vegetation concentrations of iodine-131 agree well with previously published measurements; the highest of the Phase 1 preliminary dose estimates to the thyroid are consistent with independent, previously published estimates of doses to maximally exposed individuals; and relatively crude, previously published measurements of thyroid burdens for Hanford workers are in the range of average burdens that the HEDR model estimated for similar reference individuals'' for the period 1944--1947. 4 refs., 10 figs., 9 tabs.

  1. Determination of radionuclides and pathways contributing to cumulative dose. Hanford Environmental Dose Reconstruction Project: Dose code recovery activities, Calculation 004

    SciTech Connect (OSTI)

    Napier, B.A.

    1992-12-01T23:59:59.000Z

    A series of scoping calculations has been undertaken to evaluate the absolute and relative contributions of different radionuclides and exposure pathways to doses that may have been received by individuals living in the vicinity of the Hanford Site. This scoping calculation (Calculation 004) examined the contributions of numerous radionuclides to cumulative dose via environmental exposures and accumulation in foods. Addressed in this calculation were the contributions to organ and effective dose of infants and adults from (1) air submersion and groundshine external dose, (2) inhalation, (3) ingestion of soil by humans, (4) ingestion of leafy vegetables, (5) ingestion of other vegetables and fruits, (6) ingestion of meat, (7) ingestion of eggs, and (8) ingestion of cows` milk from Feeding Regime 1, as described in calculation 002. This calculation specifically addresses cumulative radiation doses to infants and adults resulting from releases occurring over the period 1945 through 1972.

  2. Nominal effective radiation doses delivered during clinical trials of boron neutron capture therapy

    SciTech Connect (OSTI)

    Capala, J.; Diaz, A.Z.; Chanana, A.D.

    1997-12-31T23:59:59.000Z

    Boron neutron capture therapy (BNCT) is a binary system that, in theory, should selectively deliver lethal, high linear energy transfer (LET) radiation to tumor cells dispersed within normal tissues. It is based on the nuclear reaction 10-B(n, {alpha})7-Li, which occurs when the stable nucleus of boron-10 captures a thermal neutron. Due to the relatively high cross-section of the 10-B nucleus for thermal neutron capture and short ranges of the products of this reaction, tumor cells in the volume exposed to thermal neutrons and containing sufficiently high concentration of 10-B would receive a much higher radiation dose than the normal cells contained within the exposed volume. Nevertheless, radiation dose deposited in normal tissue by gamma and fast neutron contamination of the neutron beam, as well as neutron capture in nitrogen, 14-N(n,p)14-C, hydrogen, 1-H(n,{gamma})2-H, and in boron present in blood and normal cells, limits the dose that can be delivered to tumor cells. It is, therefore, imperative for the success of the BNCT the dosed delivered to normal tissues be accurately determined in order to optimize the irradiation geometry and to limit the volume of normal tissue exposed to thermal neutrons. These are the major objectives of BNCT treatment planning.

  3. Introduction of section II and overview of dose reconstruction: lessons learned from studies in the U.S.

    SciTech Connect (OSTI)

    Anspaugh, L. R, LLNL

    1997-01-01T23:59:59.000Z

    The purpose of this presentation is to provide an overview of dose reconstruction with an emphasis on the lessons learned from work in the United States. Several major dose reconstructions have been undertaken in the United States, particularly in reference to Department of Energy (DOE) facilities. Some of these activities have now been completed and these are indicated in the upper part of Table 2. The first major activity took place at the Nevada Test Site (NTS),where researchers have considered several different specific populations. The activities began with an analysis of hypothetical individuals, which was followed by an analysis of the collective dose to all exposed individuals within the surrounding region. Later, the University of Utah undertook some specific epidemiologic studies and calculated doses to specific individuals. The Hanford Environmental Dose Reconstruction Study has completed its results for hypothetical individuals. The Hanford researchers did not report collective dose. Long-Term Radiation Contamination in Chelyabinsk, Russia

  4. A Fast local Reconstruction algorithm by selective backprojection for Low-Dose in Dental Computed Tomography

    E-Print Network [OSTI]

    Bin, Yan; Yu, Han; Feng, Zhang; Chao, Wang Xian; Lei, Li

    2013-01-01T23:59:59.000Z

    High radiation dose in computed tomography (CT) scans increases the lifetime risk of cancer, which become a major clinical concern. The backprojection-filtration (BPF) algorithm could reduce radiation dose by reconstructing images from truncated data in a short scan. In dental CT, it could reduce radiation dose for the teeth by using the projection acquired in a short scan, and could avoid irradiation to other part by using truncated projection. However, the limit of integration for backprojection varies per PI-line, resulting in low calculation efficiency and poor parallel performance. Recently, a tent BPF (T-BPF) has been proposed to improve calculation efficiency by rearranging projection. However, the memory-consuming data rebinning process is included. Accordingly, the chose-BPF (C-BPF) algorithm is proposed in this paper. In this algorithm, the derivative of projection is backprojected to the points whose x coordinate is less than that of the source focal spot to obtain the differentiated backprojection...

  5. A work bibliography on native food consumption, demography and lifestyle. Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Murray, C.E.; Lee, W.J.

    1992-12-01T23:59:59.000Z

    The purpose of this report is to provide a bibliography for the Native American tribe participants in the Hanford Environmental Dose Reconstruction (HEDR) Project to use. The HEDR Project`s primary objective is to estimate the radiation dose that individuals could have received as a result of emissions since 1944 from the US Department of Energy`s Hanford Site near Richland, Washington. Eight Native American tribes are responsible for estimating daily and seasonal consumption of traditional foods, demography, and other lifestyle factors that could have affected the radiation dose received by tribal members. This report provides a bibliography of recorded accounts that tribal researchers may use to verify their estimates. The bibliographic citations include references to information on the specific tribes, Columbia River plateau ethnobotany, infant feeding practices and milk consumption, nutritional studies and radiation, tribal economic and demographic characteristics (1940--1970), research methods, primary sources from the National Archives, regional archives, libraries, and museums.

  6. A new online detector for estimation of peripheral neutron equivalent dose in organ

    SciTech Connect (OSTI)

    Irazola, L., E-mail: leticia@us.es; Sanchez-Doblado, F. [Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla 41009, Spain and Servicio de Radiofísica, Hospital Universitario Virgen Macarena, Sevilla 41007 (Spain); Lorenzoli, M.; Pola, A. [Departimento di Ingegneria Nuclear, Politecnico di Milano, Milano 20133 (Italy); Bedogni, R. [Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare (INFN), Frascati Roma 00044 (Italy); Terrón, J. A. [Servicio de Radiofísica, Hospital Universitario Virgen Macarena, Sevilla 41007 (Spain); Sanchez-Nieto, B. [Instituto de Física, Pontificia Universidad Católica de Chile, Santiago 4880 (Chile); Expósito, M. R. [Departamento de Física, Universitat Autònoma de Barcelona, Bellaterra 08193 (Spain); Lagares, J. I.; Sansaloni, F. [Centro de Investigaciones Energéticas y Medioambientales y Tecnológicas (CIEMAT), Madrid 28040 (Spain)

    2014-11-01T23:59:59.000Z

    Purpose: Peripheral dose in radiotherapy treatments represents a potential source of secondary neoplasic processes. As in the last few years, there has been a fast-growing concern on neutron collateral effects, this work focuses on this component. A previous established methodology to estimate peripheral neutron equivalent doses relied on passive (TLD, CR39) neutron detectors exposed in-phantom, in parallel to an active [static random access memory (SRAMnd)] thermal neutron detector exposed ex-phantom. A newly miniaturized, quick, and reliable active thermal neutron detector (TNRD, Thermal Neutron Rate Detector) was validated for both procedures. This first miniaturized active system eliminates the long postprocessing, required for passive detectors, giving thermal neutron fluences in real time. Methods: To validate TNRD for the established methodology, intrinsic characteristics, characterization of 4 facilities [to correlate monitor value (MU) with risk], and a cohort of 200 real patients (for second cancer risk estimates) were evaluated and compared with the well-established SRAMnd device. Finally, TNRD was compared to TLD pairs for 3 generic radiotherapy treatments through 16 strategic points inside an anthropomorphic phantom. Results: The performed tests indicate similar linear dependence with dose for both detectors, TNRD and SRAMnd, while a slightly better reproducibility has been obtained for TNRD (1.7% vs 2.2%). Risk estimates when delivering 1000 MU are in good agreement between both detectors (mean deviation of TNRD measurements with respect to the ones of SRAMnd is 0.07 cases per 1000, with differences always smaller than 0.08 cases per 1000). As far as the in-phantom measurements are concerned, a mean deviation smaller than 1.7% was obtained. Conclusions: The results obtained indicate that direct evaluation of equivalent dose estimation in organs, both in phantom and patients, is perfectly feasible with this new detector. This will open the door to an easy implementation of specific peripheral neutron dose models for any type of treatment and facility.

  7. Integrated Task Plans for the Hanford Environmental Dose Reconstruction Project, FY 1992 through May 1994

    SciTech Connect (OSTI)

    Shipler, D.B.

    1992-09-01T23:59:59.000Z

    The purpose of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate radiation doses from Hanford Site operations since 1944 to populations and individuals. The primary objective of work to be performed through May 1994 is to (1) determine the project's appropriate scope (space, time, radionuclides, pathways and individuals/population groups), (2) determine the project's appropriate level of accuracy (level of uncertainty in dose estimates) for the project, (3) complete model and data development, and (4) estimate doses for the Hanford Thyroid Disease Study (HTDS), representative individuals, and special populations as described herein. The plan for FY 1992 through May 1994 has been prepared based on activities and budgets approved by the Technical Steering Panel (TSP) at its meetings on August 19--20, 1991, and April 23--25, 1992. The activities can be divided into four broad categories: (1) model and data evaluation activities, (2)additional dose estimates, (3) model and data development activities, and (4)technical and communication support.

  8. Air pathway report: Phase I of the Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Not Available

    1991-07-01T23:59:59.000Z

    Phase 1 of the air-pathway portion of the Hanford Environmental Dose Reconstruction (HEDR) Project sought to determine whether dose estimates could be calculated for populations in the 10 counties nearest the Hanford Site from atmospheric releases of iodine-131 from the site from 1944--1947. Phase 1 demonstrated the following: HEDR-calculated source-term estimates of iodine-131 releases to the atmosphere were within 20% of previously published estimates; calculated vegetation concentrations of iodine-131 agree well with previously published measurements; the highest of the Phase 1 preliminary dose estimates to the thyroid are consistent with independent, previously published estimates of doses to maximally exposed individuals; and, relatively crude, previously published measurements of thyroid burdens for Hanford workers are in the range of average burdens that the HEDR model estimated for similar reference individuals'' for the period 1944--1947. Preliminary median dose estimates summed over the year 1945--1947 for the primary pathway, air-pasture-cow-milk-thyroid, ranged from low median values of 0.006 rad for upwind adults who obtained milk from backyard cows not on pasture to high median values of 68.0 rad for downwind infants who drank milk from pasture-fed cows. Extremes of the estimated range are a low of essentially zero to upwind adults and a high of almost 3000 rem to downwind infants. 37 refs., 37 figs., 2 tabs.

  9. Parameters used in the environmental pathways and radiological dose modules (DESCARTES, CIDER, and CRD codes) of the Hanford Environmental Dose Reconstruction Integrated Codes (HEDRIC)

    SciTech Connect (OSTI)

    Snyder, S.F.; Farris, W.T.; Napier, B.A.; Ikenberry, T.A.; Gilbert, R.O.

    1994-05-01T23:59:59.000Z

    This letter report is a description of work performed for the Hanford Environmental Dose Reconstruction (HEDR) Project. The HEDR Project was established to estimate the radiation doses to individuals resulting from releases of radionuclides from the Hanford Site during the period of 1944 to 1992. This work is being done by staff at Battelle, Pacific Northwest Laboratories under a contract with the Centers for Disease Control and Prevention with technical direction provided by an independent Technical Steering Panel (TSP).

  10. Neutron dose per fluence and weighting factors for use at high energy accelerators

    SciTech Connect (OSTI)

    Cossairt, J.Donald; Vaziri, Kamran; /Fermilab

    2008-07-01T23:59:59.000Z

    In June 2007, the United States Department of Energy incorporated revised values of neutron weighting factors into its occupational radiation protection Regulation 10 CFR Part 835 as part of updating its radiation dosimetry system. This has led to a reassessment of neutron radiation fields at high energy proton accelerators such as those at the Fermi National Accelerator Laboratory (Fermilab). Values of dose per fluence factors appropriate for accelerator radiation fields calculated elsewhere are collated and radiation weighting factors compared. The results of this revision to the dosimetric system are applied to americium-beryllium neutron energy spectra commonly used for instrument calibrations. A set of typical accelerator neutron energy spectra previously measured at Fermilab are reassessed in light of the new dosimetry system. The implications of this revision are found to be of moderate significance.

  11. Measurements of neutron dose equivalent for a proton therapy center using uniform scanning proton beams

    SciTech Connect (OSTI)

    Zheng Yuanshui; Liu Yaxi; Zeidan, Omar; Schreuder, Andries Niek; Keole, Sameer [ProCure Proton Therapy Center, 5901 West Memorial Road, Oklahoma City, Oklahoma 73142 (United States); INTEGRIS Cancer Insititute, 5911 West Memorial Road, Oklahoma City, Oklahoma 73142 (United States); ProCure Proton Therapy Center, 5901 West Memorial Road, Oklahoma City, Oklahoma 73142 (United States); ProCure Treatment Centers, 420 North Walnut Street, Bloomington, Indiana 47404 (United States); ProCure Proton Therapy Center, 5901 West Memorial Road, Oklahoma City, Oklahoma 73142 (United States)

    2012-06-15T23:59:59.000Z

    Purpose: Neutron exposure is of concern in proton therapy, and varies with beam delivery technique, nozzle design, and treatment conditions. Uniform scanning is an emerging treatment technique in proton therapy, but neutron exposure for this technique has not been fully studied. The purpose of this study is to investigate the neutron dose equivalent per therapeutic dose, H/D, under various treatment conditions for uniform scanning beams employed at our proton therapy center. Methods: Using a wide energy neutron dose equivalent detector (SWENDI-II, ThermoScientific, MA), the authors measured H/D at 50 cm lateral to the isocenter as a function of proton range, modulation width, beam scanning area, collimated field size, and snout position. They also studied the influence of other factors on neutron dose equivalent, such as aperture material, the presence of a compensator, and measurement locations. They measured H/D for various treatment sites using patient-specific treatment parameters. Finally, they compared H/D values for various beam delivery techniques at various facilities under similar conditions. Results: H/D increased rapidly with proton range and modulation width, varying from about 0.2 mSv/Gy for a 5 cm range and 2 cm modulation width beam to 2.7 mSv/Gy for a 30 cm range and 30 cm modulation width beam when 18 Multiplication-Sign 18 cm{sup 2} uniform scanning beams were used. H/D increased linearly with the beam scanning area, and decreased slowly with aperture size and snout retraction. The presence of a compensator reduced the H/D slightly compared with that without a compensator present. Aperture material and compensator material also have an influence on neutron dose equivalent, but the influence is relatively small. H/D varied from about 0.5 mSv/Gy for a brain tumor treatment to about 3.5 mSv/Gy for a pelvic case. Conclusions: This study presents H/D as a function of various treatment parameters for uniform scanning proton beams. For similar treatment conditions, the H/D value per uncollimated beam size for uniform scanning beams was slightly lower than that from a passive scattering beam and higher than that from a pencil beam scanning beam, within a factor of 2. Minimizing beam scanning area could effectively reduce neutron dose equivalent for uniform scanning beams, down to the level close to pencil beam scanning.

  12. Letter report: Media information review, 1991. Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Harvey, G.L.

    1992-04-01T23:59:59.000Z

    The media information review, requested by the Communications Subcommittee of the Technical Steering Panel (TSP), provides a general indication of the media`s areas of interests with regard to the Hanford Environmental Dose Reconstruction (HEDR) Project. This review briefly assesses 24 newspaper and magazine articles collected between September 1991 and January 1992 by Pacific Northwest Laboratory (PNL). Articles that mention the project, activities closely associated with it, or members of the Panel were included in the analysis. Attempts were made to identify general categories and issues found within the articles and display the results in an order of ranking. This review is unscientific and is not meant to display a technical analysis of the materials.

  13. Feasibility Study of Neutron Dose for Real Time Image Guided Proton Therapy: A Monte Carlo Study

    E-Print Network [OSTI]

    Kim, Jin Sung; Kim, Daehyun; Shin, EunHyuk; Chung, Kwangzoo; Cho, Sungkoo; Ahn, Sung Hwan; Ju, Sanggyu; Chung, Yoonsun; Jung, Sang Hoon; Han, Youngyih

    2015-01-01T23:59:59.000Z

    Two full rotating gantry with different nozzles (Multipurpose nozzle with MLC, Scanning Dedicated nozzle) with conventional cyclotron system is installed and under commissioning for various proton treatment options at Samsung Medical Center in Korea. The purpose of this study is to investigate neutron dose equivalent per therapeutic dose, H/D, to x-ray imaging equipment under various treatment conditions with monte carlo simulation. At first, we investigated H/D with the various modifications of the beam line devices (Scattering, Scanning, Multi-leaf collimator, Aperture, Compensator) at isocenter, 20, 40, 60 cm distance from isocenter and compared with other research groups. Next, we investigated the neutron dose at x-ray equipments used for real time imaging with various treatment conditions. Our investigation showed the 0.07 ~ 0.19 mSv/Gy at x-ray imaging equipments according to various treatment options and intestingly 50% neutron dose reduction effect of flat panel detector was observed due to multi- lea...

  14. Summary of the March 25--26, 1991 atmospheric model working meeting. Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Ramsdell, J.V.

    1992-07-01T23:59:59.000Z

    Atmospheric transport and diffusion calculations for the initial phase of the Hanford Environmental Dose Reconstruction (HEDR) Project were made using the MESOILT2 computer code (Ramsdell and Burk 1991). This code implemented a Lagrangian trajectory, puff dispersion model using components from other models designed primarily for regulatory applications. Uncertainty in the dispersion calculations was estimated following model calculations. The results of the atmospheric dispersion calculations were summarized in frequency distributions by location for use in preliminary dose calculations.

  15. Radionuclide releases to the Columbia River from Hanford Operations, 1944--1971. Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Heeb, C.M.; Bates, D.J.

    1994-01-01T23:59:59.000Z

    The purpose of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation dose that individuals could have received as a result of radionuclide emissions since 1944 from the Hanford Site. One source of radionuclide releases to the Columbia River was from production reactor operations. This report provides a quantitative estimate of the amount of radioactivity released each month (1944--1971) to the Columbia River from eleven radionuclides as well as from gross beta activity.

  16. Radionuclide releases to the Columbia River from Hanford Operations, 1944--1971. Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Heeb, C.M.; Bates, D.J.

    1994-05-01T23:59:59.000Z

    The purpose of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation dose that individuals could have received as a result of radionuclide emissions since 1944 from the Hanford Site. One source of radionuclide releases to the Columbia River was from production reactor operations. This report provides a quantitative estimate of the amount of radioactivity released each month (1944--1971) to the Columbia River from eleven radionuclides as well as from gross beta activity.

  17. Clinical implementation of a digital tomosynthesis-based seed reconstruction algorithm for intraoperative postimplant dose evaluation in low dose rate prostate brachytherapy

    SciTech Connect (OSTI)

    Brunet-Benkhoucha, Malik; Verhaegen, Frank; Lassalle, Stephanie; Beliveau-Nadeau, Dominic; Reniers, Brigitte; Donath, David; Taussky, Daniel; Carrier, Jean-Francois [Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4 (Canada) and Departement de Radio-Oncologie, Centre Hospitalier de l'Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada); Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4 (Canada) and Department of Radiation Oncology (MAASTRO), GROW Research Institute, University Medical Centre Maastricht, Maastricht (Netherlands); Departement de Radio-Oncologie, Centre Hospitalier de l'Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada); Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4 (Canada) and Department of Radiation Oncology (MAASTRO), GROW Research Institute, University Medical Centre Maastricht, Maastricht (Netherlands); Departement de Radio-Oncologie, Centre Hospitalier de l'Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada); Departement de Radio-Oncologie, Centre Hospitalier de l'Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada) and CRCHUM, Centre Hospitalier de l'Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada)

    2009-11-15T23:59:59.000Z

    Purpose: The low dose rate brachytherapy procedure would benefit from an intraoperative postimplant dosimetry verification technique to identify possible suboptimal dose coverage and suggest a potential reimplantation. The main objective of this project is to develop an efficient, operator-free, intraoperative seed detection technique using the imaging modalities available in a low dose rate brachytherapy treatment room. Methods: This intraoperative detection allows a complete dosimetry calculation that can be performed right after an I-125 prostate seed implantation, while the patient is still under anesthesia. To accomplish this, a digital tomosynthesis-based algorithm was developed. This automatic filtered reconstruction of the 3D volume requires seven projections acquired over a total angle of 60 deg. with an isocentric imaging system. Results: A phantom study was performed to validate the technique that was used in a retrospective clinical study involving 23 patients. In the patient study, the automatic tomosynthesis-based reconstruction yielded seed detection rates of 96.7% and 2.6% false positives. The seed localization error obtained with a phantom study is 0.4{+-}0.4 mm. The average time needed for reconstruction is below 1 min. The reconstruction algorithm also provides the seed orientation with an uncertainty of 10 deg. {+-}8 deg. The seed detection algorithm presented here is reliable and was efficiently used in the clinic. Conclusions: When combined with an appropriate coregistration technique to identify the organs in the seed coordinate system, this algorithm will offer new possibilities for a next generation of clinical brachytherapy systems.

  18. Atmospheric transport and dispersion modeling for the Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Ramsdell, J.V.

    1991-07-01T23:59:59.000Z

    Radiation doses that may have resulted from operations at the Hanford Site are being estimated in the Hanford Environmental Dose Reconstruction (HEDR) Project. One of the project subtasks, atmospheric transport, is responsible for estimating the transport, diffusion and deposition of radionuclides released to the atmosphere. This report discusses modeling transport and diffusion in the atmospheric pathway. It is divided into three major sections. The first section of the report presents the atmospheric modeling approach selected following discussion with the Technical Steering Panel that directs the HEDR Project. In addition, the section discusses the selection of the MESOI/MESORAD suite of atmospheric dispersion models that form the basis for initial calculations and future model development. The second section of the report describes alternative modeling approaches that were considered. Emphasis is placed on the family of plume and puff models that are based on Gaussian solution to the diffusion equations. The final portion of the section describes the performance of various models. The third section of the report discusses factors that bear on the selection of an atmospheric transport modeling approach for HEDR. These factors, which include the physical setting of the Hanford Site and the available meteorological data, serve as constraints on model selection. Five appendices are included in the report. 39 refs., 4 figs., 2 tabs.

  19. Historical Evaluation of Film Badge Dosimetry Y-12 Plant: Part 2–Neutron Radiation ORAUT-OTIB-0045

    SciTech Connect (OSTI)

    Kerr GD, Frome EL, Watkins JP, Tankersley WG

    2009-12-14T23:59:59.000Z

    A summary of the major neutron sources involved in radiation exposures to Y-12 workers is presented in this TIB. Graphical methods are used to evaluate available neutron dose data from quarterly exposures to Y-12 workers and to determine how the data could be used to derive neutron-to-gamma dose ratios for dose reconstruction purposes. This TIB provides estimates of neutron-to-gamma dose ratios for specific departments and a default value for the neutron-to-gamma dose ratio based on the pooled neutron dose data for all Y-12 departments.

  20. Measurement of neutron dose equivalent outside and inside of the treatment vault of GRID therapy

    SciTech Connect (OSTI)

    Wang, Xudong; Charlton, Michael A.; Esquivel, Carlos; Eng, Tony Y.; Li, Ying; Papanikolaou, Nikos [University of Texas Health Science Center, San Antonio, Texas 78229 (United States)] [University of Texas Health Science Center, San Antonio, Texas 78229 (United States)

    2013-09-15T23:59:59.000Z

    Purpose: To evaluate the neutron and photon dose equivalent rates at the treatment vault entrance (H{sub n,D} and H{sub G}), and to study the secondary radiation to the patient in GRID therapy. The radiation activation on the grid was studied.Methods: A Varian Clinac 23EX accelerator was working at 18 MV mode with a grid manufactured by .decimal, Inc. The H{sub n,D} and H{sub G} were measured using an Andersson–Braun neutron REM meter, and a Geiger Müller counter. The radiation activation on the grid was measured after the irradiation with an ion chamber ?-ray survey meter. The secondary radiation dose equivalent to patient was evaluated by etched track detectors and OSL detectors on a RANDO{sup ®} phantom.Results: Within the measurement uncertainty, there is no significant difference between the H{sub n,D} and H{sub G} with and without a grid. However, the neutron dose equivalent to the patient with the grid is, on average, 35.3% lower than that without the grid when using the same field size and the same amount of monitor unit. The photon dose equivalent to the patient with the grid is, on average, 44.9% lower. The measured average half-life of the radiation activation in the grid is 12.0 (±0.9) min. The activation can be categorized into a fast decay component and a slow decay component with half-lives of 3.4 (±1.6) min and 15.3 (±4.0) min, respectively. There was no detectable radioactive contamination found on the surface of the grid through a wipe test.Conclusions: This work indicates that there is no significant change of the H{sub n,D} and H{sub G} in GRID therapy, compared with a conventional external beam therapy. However, the neutron and scattered photon dose equivalent to the patient decrease dramatically with the grid and can be clinical irrelevant. Meanwhile, the users of a grid should be aware of the possible high dose to the radiation worker from the radiation activation on the surface of the grid. A delay in handling the grid after the beam delivery is suggested.

  1. Regional Atmospheric Transport Code for Hanford Emission Tracking (RATCHET). Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Ramsdell, J.V. Jr.; Simonen, C.A.; Burk, K.W.

    1994-02-01T23:59:59.000Z

    The purpose of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate radiation doses that individuals may have received from operations at the Hanford Site since 1944. This report deals specifically with the atmospheric transport model, Regional Atmospheric Transport Code for Hanford Emission Tracking (RATCHET). RATCHET is a major rework of the MESOILT2 model used in the first phase of the HEDR Project; only the bookkeeping framework escaped major changes. Changes to the code include (1) significant changes in the representation of atmospheric processes and (2) incorporation of Monte Carlo methods for representing uncertainty in input data, model parameters, and coefficients. To a large extent, the revisions to the model are based on recommendations of a peer working group that met in March 1991. Technical bases for other portions of the atmospheric transport model are addressed in two other documents. This report has three major sections: a description of the model, a user`s guide, and a programmer`s guide. These sections discuss RATCHET from three different perspectives. The first provides a technical description of the code with emphasis on details such as the representation of the model domain, the data required by the model, and the equations used to make the model calculations. The technical description is followed by a user`s guide to the model with emphasis on running the code. The user`s guide contains information about the model input and output. The third section is a programmer`s guide to the code. It discusses the hardware and software required to run the code. The programmer`s guide also discusses program structure and each of the program elements.

  2. Simulation of in-core neutron noise measurements for axial void profile reconstruction in boiling water reactors

    SciTech Connect (OSTI)

    Dykin, V.; Pazsit, I. [Chalmers Univ. of Technology, Div. of Nuclear Engineering, Dept. of Applied Physics, SE-412 96 Gothenburg (Sweden)

    2012-07-01T23:59:59.000Z

    A possibility to reconstruct the axial void profile from the simulated in-core neutron noise which is caused by density fluctuations in a Boiling Water Reactor (BWR) heated channel is considered. For this purpose, a self-contained model of the two-phase flow regime is constructed which has quantitatively and qualitatively similar properties to those observed in real BWRs. The model is subsequently used to simulate the signals of neutron detectors induced by the corresponding perturbations in the flow density. The bubbles are generated randomly in both space and time using Monte-Carlo techniques. The axial distribution of the bubble production is chosen such that the mean axial void fraction and void velocity follow the actual values of BWRs. The induced neutron noise signals are calculated and then processed by the standard signal analysis methods such as Auto-Power Spectral Density (APSD) and Cross-Power Spectral Density (CPSD). Two methods for axial void and velocity profiles reconstruction are discussed: the first one is based on the change of the break frequency of the neutron auto-power spectrum with axial core elevation, while the second refers to the estimation of transit times of propagating steam fluctuations between different axial detector positions. This paper summarizes the principles of the model and presents a numerical testing of the qualitative applicability to estimate the required parameters for the reconstruction of the void fraction profile from the neutron noise measurements. (authors)

  3. Evaluation of few-view reconstruction parameters for illicit substance detection using fast-neutron transmission spectroscopy

    SciTech Connect (OSTI)

    Fink, C.L.; Humm, P.G.; Martin, M.M.; Micklich, B.J. [Argonne National Lab., IL (United States)] [Argonne National Lab., IL (United States)

    1996-06-01T23:59:59.000Z

    The authors have evaluated the performance of an illicit substance detection system that performs image reconstruction using the Maximum Likelihood algebraic reconstruction algorithm, a fe number of projections, and relatively coarse projection and pixel resolution. This evaluation was done using receiver operator curves and simulated data from the fast-neutron transmission spectroscopy system operated in a mode to detect explosives in luggage. The results show that increasing the number of projection angles is more important than increasing the projection resolution, the reconstructed pixel resolution, of the number of iterations in the Maximum Likelihood algorithm. A 100% detection efficiency with essentially no false positives is possible for a square block of RDX explosive, a projection resolution of 2 cm, a reconstructed pixel size of 2x2 cm, and five projection angles. For rectangular shaped explosives more angles are required to obtain the same system performance.

  4. Statistical models and regularization strategies in statistical image reconstruction of low-dose X-ray computed tomography: a survey

    E-Print Network [OSTI]

    Zhang, Hao; Ma, Jianhua; Lu, Hongbing; Liang, Zhengrong

    2014-01-01T23:59:59.000Z

    Statistical image reconstruction (SIR) methods have shown potential to substantially improve the image quality of low-dose X-ray computed tomography (CT) as compared to the conventional filtered back-projection (FBP) method for various clinical tasks. According to the maximum a posterior (MAP) estimation, the SIR methods can be typically formulated by an objective function consisting of two terms: (1) data-fidelity (or equivalently, data-fitting or data-mismatch) term modeling the statistics of projection measurements, and (2) regularization (or equivalently, prior or penalty) term reflecting prior knowledge or expectation on the characteristics of the image to be reconstructed. Existing SIR methods for low-dose CT can be divided into two groups: (1) those that use calibrated transmitted photon counts (before log-transform) with penalized maximum likelihood (pML) criterion, and (2) those that use calibrated line-integrals (after log-transform) with penalized weighted least-squares (PWLS) criterion. Accurate s...

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

    SciTech Connect (OSTI)

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

    2013-08-15T23:59:59.000Z

    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 ?·E at the screen.

  6. Conversion and correction factors for historical measurements of Iodine-131 in Hanford-area vegetation, 1945--1947: Draft. Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Mart, E.I.; Denham, D.H.; Thiede, M.E.

    1993-05-01T23:59:59.000Z

    This report is a result of the Hanford Environmental Dose Reconstruction (HEDR) Project whose goal is to estimate the radiation dose that individuals could have received from emissions since 1944 at the US Department of Energy`s (DOE) Hanford Site near Richland, Washington. The report describes in detail the reconstructed conversion and correction factors for historical measurements of iodine-131 in Hanford-area vegetation which was collected from the beginning of October 1945 through the end of December 1947.

  7. Evaluation of few-view reconstruction parameters for illicit substance detection using fast-neutron transmission spectroscopy

    SciTech Connect (OSTI)

    Fink, C.L.; Humm, P.G.; Micklich, B.J.

    1995-12-31T23:59:59.000Z

    We have evaluated the performance of the Maximum Likelihood algebraic reconstruction algorithm for the case of a few projections and for relatively coarse projection and pixel resolution. Ibis evaluation was done using receiver operator curves obtained from the fast neutron transmission spectroscopy system operated in a mode to detect explosives in luggage. The results show that increasing the number of projection angles is more important than increasing the projection resolution, the reconstructed pixel resolution, or the number of iterations in the Maximum Likelihood algorithm. A 100% detection efficiency with essentially no false positives is possible for a square block of RDX explosive, a projection resolution of 2 cm, a reconstructed pixel size of 2 {times} 2 cm, and five projection angles. For rectangular shaped explosives more angles are required obtain the same system performance.

  8. Defect annealing and thermal desorption of deuterium in low dose HFIR neutron-irradiated tungsten

    SciTech Connect (OSTI)

    Masashi Shimada; M. Hara; T. Otsuka; Y. Oya; Y. Hatano

    2014-05-01T23:59:59.000Z

    Accurately estimating tritium retention in plasma facing components (PFCs) and minimizing its uncertainty are key safety issues for licensing future fusion power reactors. D-T fusion reactions produce 14.1 MeV neutrons that activate PFCs and create radiation defects throughout the bulk of the material of these components. Recent studies show that tritium migrates and is trapped in bulk (>> 10 µm) tungsten beyond the detection range of nuclear reaction analysis technique [1-2], and thermal desorption spectroscopy (TDS) technique becomes the only established diagnostic that can reveal hydrogen isotope behavior in in bulk (>> 10 µm) tungsten. Radiation damage and its recovery mechanisms in neutron-irradiated tungsten are still poorly understood, and neutron-irradiation data of tungsten is very limited. In this paper, systematic investigations with repeated plasma exposures and thermal desorption are performed to study defect annealing and thermal desorption of deuterium in low dose neutron-irradiated tungsten. Three tungsten samples (99.99 at. % purity from A.L.M.T. Co., Japan) irradiated at High Flux Isotope Reactor at Oak Ridge National Laboratory were exposed to high flux (ion flux of (0.5-1.0)x1022 m-2s-1 and ion fluence of 1x1026 m-2) deuterium plasma at three different temperatures (100, 200, and 500 °C) in Tritium Plasma Experiment at Idaho National Laboratory. Subsequently, thermal desorption spectroscopy (TDS) was performed with a ramp rate of 10 °C/min up to 900 °C, and the samples were annealed at 900 °C for 0.5 hour. These procedures were repeated three (for 100 and 200 °C samples) and four (for 500 °C sample) times to uncover damage recovery mechanisms and its effects on deuterium behavior. The results show that deuterium retention decreases approximately 90, 75, and 66 % for 100, 200, and 500 °C, respectively after each annealing. When subjected to the same TDS recipe, the desorption temperature shifts from 800 °C to 600 °C after 1st annealing for the sample exposed to TPE at 500 °C. Tritium Migration Analysis Program (TMAP) analysis reveals that the detrapping energy decreases from 1.8 eV to 1.4 eV, indicating the changes in trapping mechanisms. This paper also summarizes deuterium behavior studies in HFIR neutron-irradiated tungsten under US-Japan TITAN program.

  9. Determination of radionuclides and pathways contributing to dose in 1945. Hanford Environmental Dose Reconstruction Project: Dose code recovery activities, Calculation 003

    SciTech Connect (OSTI)

    Napier, B.A.

    1992-12-01T23:59:59.000Z

    A series of scoping calculations has been undertaken to evaluate the absolute and relative contributions of different radionuclides and exposure pathways to doses that may have been received by individuals living in the vicinity of the Hanford Site. This scoping calculation (Calculation 003) examined the contributions of numerous radionuclides to dose via environmental exposures and accumulation in foods. This study builds on the work initiated in the first scoping study of iodine in cow`s milk (calculation 001). Addressed in this calculation were the contributions to organ and effective dose of infants and adults from (1) air submersion and groundshine external dose, (2) inhalation, (3) ingestion of soil by humans, (4) ingestion of leafy vegetables, (5) ingestion of other vegetables and fruits, (6) ingestion of meat, (7) ingestion of eggs, and (8) ingestion of cows` milk from Feeding Regime 1, as described in Calculation 001.

  10. Characterization of the neutron irradiation system for use in the Low-Dose-Rate Irradiation Facility at Sandia National Laboratories.

    SciTech Connect (OSTI)

    Franco, Manuel,

    2014-08-01T23:59:59.000Z

    The objective of this work was to characterize the neutron irradiation system consisting of americium-241 beryllium (241AmBe) neutron sources placed in a polyethylene shielding for use at Sandia National Laboratories (SNL) Low Dose Rate Irradiation Facility (LDRIF). With a total activity of 0.3 TBq (9 Ci), the source consisted of three recycled 241AmBe sources of different activities that had been combined into a single source. The source in its polyethylene shielding will be used in neutron irradiation testing of components. The characterization of the source-shielding system was necessary to evaluate the radiation environment for future experiments. Characterization of the source was also necessary because the documentation for the three component sources and their relative alignment within the Special Form Capsule (SFC) was inadequate. The system consisting of the source and shielding was modeled using Monte Carlo N-Particle transport code (MCNP). The model was validated by benchmarking it against measurements using multiple techniques. To characterize the radiation fields over the full spatial geometry of the irradiation system, it was necessary to use a number of instruments of varying sensitivities. First, the computed photon radiography assisted in determining orientation of the component sources. With the capsule properly oriented inside the shielding, the neutron spectra were measured using a variety of techniques. A N-probe Microspec and a neutron Bubble Dosimeter Spectrometer (BDS) set were used to characterize the neutron spectra/field in several locations. In the third technique, neutron foil activation was used to ascertain the neutron spectra. A high purity germanium (HPGe) detector was used to characterize the photon spectrum. The experimentally measured spectra and the MCNP results compared well. Once the MCNP model was validated to an adequate level of confidence, parametric analyses was performed on the model to optimize for potential experimental configurations and neutron spectra for component irradiation. The final product of this work is a MCNP model validated by measurements, an overall understanding of neutron irradiation system including photon/neutron transport and effective dose rates throughout the system, and possible experimental configurations for future irradiation of components.

  11. Letter report: Population estimates by age, sex and race for 10-county study area. Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Pittenger, D.B.

    1992-02-01T23:59:59.000Z

    The Hanford Environmental Does Reconstruction (HEDR) Project was established to estimate radiation doses that people could have received from nuclear operations at the Hanford Site since 1944. To identify groups that may have received doses, population estimates containing age, race, and sex detail for ten counties in Washington and Oregon for the years 1940 to 1980 were prepared by the Demographics Laboratory under a subcontract with the Pacific Northwest Laboratory (PNL). A data base of population information was developed from census reports and published and unpublished collections from the Washington State Office of Financial Management and Center for Population Research. Three estimation methods were then explored: the cohort-component model, cohort interpolation, and age-group interpolation. The estimates generated through cohort and age-group interpolation are considered adequate for initial use in the HEDR Project. Results are presented in two forms: (1) county populations by sex and single year of age and (2) county populations by sex and race for age groupings. These results are made available to the HEDR Project for further refinement into population estimates by county census divisions.

  12. Literature and data review for the surface-water pathway: Columbia River and adjacent coastal areas. Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Walters, W.H.; Dirkes, R.L.; Napier, B.A.

    1992-04-01T23:59:59.000Z

    As part of the Hanford Environmental Dose Reconstruction Project, Pacific Northwest Laboratory reviewed literature and data on radionuclide concentrations and distribution in the water, sediment, and biota of the Columbia River and adjacent coastal areas. Over 600 documents were reviewed including Hanford reports, reports by offsite agencies, journal articles, and graduate theses. Certain radionuclide concentration data were used in preliminary estimates of individual dose for the 1964--1966 time period. This report summarizes the literature and database review and the results of the preliminary dose estimates.

  13. 3D inpatient dose reconstruction from the PET-CT imaging of {sup 90}Y microspheres for metastatic cancer to the liver: Feasibility study

    SciTech Connect (OSTI)

    Fourkal, E.; Veltchev, I.; Lin, M.; Meyer, J. [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 (United States)] [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 (United States); Koren, S. [Department of Radiation Oncology, Beth Israel Comprehensive Cancer Center, New York, New York 10011 (United States)] [Department of Radiation Oncology, Beth Israel Comprehensive Cancer Center, New York, New York 10011 (United States); Doss, M.; Yu, J. Q. [Department of Diagnostic Imaging, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 (United States)] [Department of Diagnostic Imaging, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 (United States)

    2013-08-15T23:59:59.000Z

    Purpose: The introduction of radioembolization with microspheres represents a significant step forward in the treatment of patients with metastatic disease to the liver. This technique uses semiempirical formulae based on body surface area or liver and target volumes to calculate the required total activity for a given patient. However, this treatment modality lacks extremely important information, which is the three-dimensional (3D) dose delivered by microspheres to different organs after their administration. The absence of this information dramatically limits the clinical efficacy of this modality, specifically the predictive power of the treatment. Therefore, the aim of this study is to develop a 3D dose calculation technique that is based on the PET imaging of the infused microspheres.Methods: The Fluka Monte Carlo code was used to calculate the voxel dose kernel for {sup 90}Y source with voxel size equal to that of the PET scan. The measured PET activity distribution was converted to total activity distribution for the subsequent convolution with the voxel dose kernel to obtain the 3D dose distribution. In addition, dose-volume histograms were generated to analyze the dose to the tumor and critical structures.Results: The 3D inpatient dose distribution can be reconstructed from the PET data of a patient scanned after the infusion of microspheres. A total of seven patients have been analyzed so far using the proposed reconstruction method. Four patients underwent treatment with SIR-Spheres for liver metastases from colorectal cancer and three patients were treated with Therasphere for hepatocellular cancer. A total of 14 target tumors were contoured on post-treatment PET-CT scans for dosimetric evaluation. Mean prescription activity was 1.7 GBq (range: 0.58–3.8 GBq). The resulting mean maximum measured dose to targets was 167 Gy (range: 71–311 Gy). Mean minimum dose to 70% of target (D70) was 68 Gy (range: 25–155 Gy). Mean minimum dose to 90% of target (D90) was 53 Gy (range: 13–125 Gy).Conclusions: A three-dimensional inpatient dose reconstruction method has been developed that is based on the PET/CT data of a patient treated with {sup 90}Y microspheres. It allows for a complete description of the absorbed dose by the tumor and critical structures. It represents the first step in building predictive models for treatment outcomes for patients receiving this therapeutic modality as well as it allows for better analysis of patients' dose response and will ultimately improve future treatment administration.

  14. Comparison of secondary neutron dose in proton therapy resulting from the use of a tungsten alloy MLC or a brass collimator system

    SciTech Connect (OSTI)

    Diffenderfer, Eric S.; Ainsley, Christopher G.; Kirk, Maura L.; McDonough, James E.; Maughan, Richard L. [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

    2011-11-15T23:59:59.000Z

    Purpose: To apply the dual ionization chamber method for mixed radiation fields to an accurate comparison of the secondary neutron dose arising from the use of a tungsten alloy multileaf collimator (MLC) as opposed to a brass collimator system for defining the shape of a therapeutic proton field. Methods: Hydrogenous and nonhydrogenous ionization chambers were constructed with large volumes to enable measurements of absorbed doses below 10{sup -4} Gy in mixed radiation fields using the dual ionization chamber method for mixed-field dosimetry. Neutron dose measurements were made with a nominal 230 MeV proton beam incident on a closed tungsten alloy MLC and a solid brass block. The chambers were cross-calibrated against a {sup 60}Co-calibrated Farmer chamber in water using a 6 MV x-ray beam and Monte Carlo simulations were performed to account for variations in ionization chamber response due to differences in secondary neutron energy spectra. Results: The neutron and combined proton plus {gamma}-ray absorbed doses are shown to be nearly equivalent downstream from either a closed tungsten alloy MLC or a solid brass block. At 10 cm downstream from the distal edge of the collimating material the neutron dose from the closed MLC was (5.3 {+-} 0.4) x 10{sup -5} Gy/Gy. The neutron dose with brass was (6.4 {+-} 0.7) x 10{sup -5} Gy/Gy. Further from the secondary neutron source, at 50 cm, the neutron doses remain close for both the MLC and brass block at (6.9 {+-} 0.6) x 10{sup -6} Gy/Gy and (6.3 {+-} 0.7) x 10{sup -6} Gy/Gy, respectively. Conclusions: The dual ionization chamber method is suitable for measuring secondary neutron doses resulting from proton irradiation. The results of measurements downstream from a closed tungsten alloy MLC and a brass block indicate that, even in an overly pessimistic worst-case scenario, secondary neutron production in a tungsten alloy MLC leads to absorbed doses that are nearly equivalent to those seen from brass collimators. Therefore, the choice of tungsten alloy in constructing the leaves of a proton MLC is appropriate, and does not lead to a substantial increase in the secondary neutron dose to the patient compared to that generated in a brass collimator.

  15. Calculation of extremity neutron fluence-to-dose equivalent conversion factors

    E-Print Network [OSTI]

    Wood-Zika, Annmarie Ruth

    1997-01-01T23:59:59.000Z

    surface fluence spectra 45 LIST OF TABLES TABLE Page Properties of commercially available TLDs . . PNNL dose equivalent averaged quality factors . 16 3 MCNP input deck geometries Phantoms modeled in MCNP input decks . . Comparison of calculated..., PNNL and DOELAP fluence-to-dose equivalent conversion factors for bare '"Cf . . . . 37 Comparison of calculated, PNNL and DOELAP fluence-to-dose equivalent conversion factors for D, O moderated '"Cf. 37 Fluence-to-dose equivalent conversion factors...

  16. Use of international data sets to evaluate and validate pathway assessment models applicable to exposure and dose reconstruction at DOE facilities. Progress report, August 1993--January 1994

    SciTech Connect (OSTI)

    Hendrickson, S.M. [ed.] [Lawrence Livermore National Lab., CA (United States)] [ed.; Lawrence Livermore National Lab., CA (United States); Hoffman, F.O. [Senes Oak Ridge, Inc., TN (United States). Center for Risk Analysis] [Senes Oak Ridge, Inc., TN (United States). Center for Risk Analysis

    1994-03-01T23:59:59.000Z

    This project, ``Use of International Data Sets to Evaluate and Validate Pathway Assessment Models Applicable to Exposure and Dose Reconstruction at DOE Facilities,`` grew out of several activities being conducted by the Principal Investigator Dr. F Owen Hoffman. One activity was originally part of the Chernobyl Studies Project and began as Task 7.1D, ``Internal Dose From Direct Contamination of Terrestrial Food Sources.`` The objective of Task 7.1D was to (1) establish a collaborative US USSR effort to improve and validate our methods of forecasting doses and dose commitments from the direct contamination of food sources, and (2) perform experiments and validation studies to improve our ability to predict rapidly and accurately the long-term internal dose from the contamination of agricultural soil. The latter was to include the consideration of remedial measures to block contamination of food grown on contaminated soil. The current objective of this project is to evaluate and validate pathway-assessment models applicable to exposure and dose reconstruction at DOE facilities through use of international data sets. This project incorporates the activity of Task 7.1D into a multinational effort to evaluate data used for the prediction of radionuclide transfer through agricultural and aquatic systems to humans. It also includes participation in two multinational studies, BIOMOVS (BIOspheric MOdel Validation Study) with the Swedish National Institute for Radiation Protection and VAMP (VAlidation of Model Predictions) with the International Atomic Energy Agency, that address testing the performance of models of radionuclide transport through foodchains.

  17. SU-E-I-82: Improving CT Image Quality for Radiation Therapy Using Iterative Reconstruction Algorithms and Slightly Increasing Imaging Doses

    SciTech Connect (OSTI)

    Noid, G; Chen, G; Tai, A; Li, X [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI (United States)

    2014-06-01T23:59:59.000Z

    Purpose: Iterative reconstruction (IR) algorithms are developed to improve CT image quality (IQ) by reducing noise without diminishing spatial resolution or contrast. For CT in radiation therapy (RT), slightly increasing imaging dose to improve IQ may be justified if it can substantially enhance structure delineation. The purpose of this study is to investigate and to quantify the IQ enhancement as a result of increasing imaging doses and using IR algorithms. Methods: CT images were acquired for phantoms, built to evaluate IQ metrics including spatial resolution, contrast and noise, with a variety of imaging protocols using a CT scanner (Definition AS Open, Siemens) installed inside a Linac room. Representative patients were scanned once the protocols were optimized. Both phantom and patient scans were reconstructed using the Sinogram Affirmed Iterative Reconstruction (SAFIRE) and the Filtered Back Projection (FBP) methods. IQ metrics of the obtained CTs were compared. Results: IR techniques are demonstrated to preserve spatial resolution as measured by the point spread function and reduce noise in comparison to traditional FBP. Driven by the reduction in noise, the contrast to noise ratio is doubled by adopting the highest SAFIRE strength. As expected, increasing imaging dose reduces noise for both SAFIRE and FBP reconstructions. The contrast to noise increases from 3 to 5 by increasing the dose by a factor of 4. Similar IQ improvement was observed on the CTs for selected patients with pancreas and prostrate cancers. Conclusion: The IR techniques produce a measurable enhancement to CT IQ by reducing the noise. Increasing imaging dose further reduces noise independent of the IR techniques. The improved CT enables more accurate delineation of tumors and/or organs at risk during RT planning and delivery guidance.

  18. A comparison of neutron dose measurement techniques at the K500 Superconducting Cyclotron facility

    E-Print Network [OSTI]

    Ford, Michael Scott

    1989-01-01T23:59:59.000Z

    - tivity in accelerator components, and thus contributing to personnel exposure, than are the cascade neutrons, since evaporation particles are considerably more numerous and their energy is more favorable for capture (Patterson and Thomas 1973... generated by the superconducting accelerator (K500). The existing dosimeter system utilized both the Kodak~ Neutron Track Analysis (NTA) film and GARDRAYIII' 8 mm beta, x, and gamma ray film. The proposed system incorporated a TLD albedo dosimeter and a...

  19. Verification and validation of the maximum entropy method for reconstructing neutron flux, with MCNP5, Attila-7.1.0 and the GODIVA experiment

    SciTech Connect (OSTI)

    Douglas S. Crawford; Tony Saad; Terry A. Ring

    2013-03-01T23:59:59.000Z

    Verification and validation of reconstructed neutron flux based on the maximum entropy method is presented in this paper. The verification is carried out by comparing the neutron flux spectrum from the maximum entropy method with Monte Carlo N Particle 5 version 1.40 (MCNP5) and Attila-7.1.0-beta (Attila). A spherical 100% 235U critical assembly is modeled as the test case to compare the three methods. The verification error range for the maximum entropy method is 15–21% where MCNP5 is taken to be the comparison standard. Attila relative error for the critical assembly is 20–35%. Validation is accomplished by comparing a neutron flux spectrum that is back calculated from foil activation measurements performed in the GODIVA experiment (GODIVA). The error range of the reconstructed flux compared to GODIVA is 0–10%. The error range of the neutron flux spectrum from MCNP5 compared to GODIVA is 0–20% and the Attila error range compared to the GODIVA is 0–35%. The maximum entropy method is shown to be a fast reliable method, compared to either Monte Carlo methods (MCNP5) or 30 multienergy group methods (Attila) and with respect to the GODIVA experiment.

  20. Task 3 Report - PCBs in the Environment Near the Oak Ridge Reservation - A Reconstruction of Historical Doses and Health Risks

    SciTech Connect (OSTI)

    Price, Paul S; Widner, Thomas; Bonnevie, Nancy; Schmidt, Charlie; McCrodden-Hamblen, Jane; Vantaggio, Joanne; Gwinn, Patrick

    1999-07-01T23:59:59.000Z

    This report presents the results of an in-depth assessment of historical releases of polychlorinated biphenyls (PCBs) from the Oak Ridge Reservation (ORR) and risks of adverse health effects in local populations. The study was conducted by ChemRisk, a service of McLaren/Hart, Inc., for the Tennessee Department of Health. The project team (1) investigated releases of PCBs from the government sites, (2) evaluated PCB levels in environmental media in the area, (3) described releases of PCBs from other sources in the area, and (4) evaluated potential human exposures and health impacts associated with the historical presence of these contaminants in the environment. Beginning in the 1940s, PCBs were used extensively on the ORR and throughout the U.S. as a fire retardant in electrical components. PCBs were also used as cutting fluids for lubrication and cooling during metal working operations. Using information specific to the ORR, the project team estimated health risks for five off-site populations: (1) farm families that raised beef, dairy cattle, and vegetables on the flood plain of East Fork Poplar Creek (EFPC); (2) individuals who may have purchased beef and milk from cattle raised in the EFPC flood plain; (3) commercial and recreational fish consumers; (4) individuals that may have consumed turtles; and (5) users of surface water for recreation. Noteworthy features of the study include a two-dimensional analysis of uncertainty and variability in the non-cancer risk estimates and an assessment of the uncertainty in PCB toxicology thresholds. Conservative estimates of cancer risks from the ORR releases of PCBs to consumers of fish from Watts Bar Reservoir and the Clinch River range from less than 1 in a 1,000,000 to 2 in 10,000. Three or less excess cases of cancer would be expected to occur among individuals who consumed fish from these local waters since the 1940's. Persons who consumed large amounts of fish from the Clinch R. and Watts Bar were also at risk from non -cancer effects of PCBs. However, for Watts Bar, these risks were mainly due to sources of PCBs other than the ORR; the releases from the ORR appear to have placed an additional one to two percent of the total number of fish consumers potentially at risk. This percentage corresponds to approximately 1,000-2,000 fish consumers over the last 50 years. This report is one in a set of eight technical reports on the Oak Ridge Offsite Dose Reconstruction.

  1. Defect Sink Characteristics of Specific Grain Boundary Types in 304 Stainless Steels Under High Dose Neutron Environments

    SciTech Connect (OSTI)

    Field, Kevin G [ORNL; Yang, Ying [ORNL; Busby, Jeremy T [ORNL

    2015-01-01T23:59:59.000Z

    Radiation induced segregation (RIS) is a well-studied phenomena which occurs in many structurally relevant nuclear materials including austenitic stainless steels. RIS occurs due to solute atoms preferentially coupling to mobile point defect fluxes that migrate and interact with defect sinks. Here, a 304 stainless steel was neutron irradiated up to 47.1 dpa at 320 C. Investigations into the RIS response at specific grain boundary types were utilized to determine the sink characteristics of different boundary types as a function of irradiation dose. A rate theory model built on the foundation of the modified inverse Kirkendall (MIK) model is proposed and benchmarked to the experimental results. This model, termed the GiMIK model, includes alterations in the boundary conditions based on grain boundary structure and includes expressions for interstitial binding. This investigation, through experiment and modeling, found specific grain boundary structures exhibit unique defect sink characteristics depending on their local structure. Such interactions were found to be consistent across all doses investigated and had larger global implications including precipitation of Ni-Si clusters near different grain boundary types.

  2. Irradiation effect on deuterium behaviour in low-dose HFIR neutron-irradiated tungsten

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Shimada, Masashi; Cao, G.; Otsuka, T.; Hara, M.; Kobayashi, M.; Oya, Y.; Hatano, Y.

    2015-01-01T23:59:59.000Z

    Tungsten samples were irradiated by neutrons in the High Flux Isotope Reactor (HFIR), Oak Ridge National Laboratory at reactor coolant temperatures of 50–70 ?C to low displacement damage of 0.025 and 0.3 dpa. After cooling down, the HFIR neutronirradiated tungsten samples were exposed to deuterium plasmas in the Tritium Plasma Experiment, Idaho National Laboratory at 100, 200 and 500 ?C twice at the ion fluence of 5×1025 m-2 to reach the total ion fluence of 1×1026 m-2 in order to investigate maximum near-surface (more »in 0.3 dpa samples. The large discrepancy between the total retention via thermal desorption spectroscopy and the nearsurface retention via nuclear reaction analysis indicated the deuterium was trapped in bulk (at least 50µm depth for 0.025 dpa and 35µm depth for 0.3 dpa) at 500 ?C cases even in the relatively low ion fluence of 1026 m-2.« less

  3. Irradiation effect on deuterium behaviour in low-dose HFIR neutron-irradiated tungsten

    SciTech Connect (OSTI)

    Shimada, Masashi [Idaho National Lab. (INL), Idaho Falls, ID (United States).Fusion Safety Program; Cao, G. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Engineering Physics; Otsuka, T. [Kyushu Univ., Fukuoka (Japan). Interdisciplinary Graduate School of Engineering Science; Hara, M. [Univ. of Toyama (Japan). Hydrogen Isotope Center; Kobayashi, M. [Shizuoka Univ. (Japan). Radioscience Research Lab.; Oya, Y. [Shizuoka Univ. (Japan). Radioscience Research Lab.; Hatano, Y. [Shizuoka Univ. (Japan). Radioscience Research Lab.

    2015-01-01T23:59:59.000Z

    Tungsten samples were irradiated by neutrons in the High Flux Isotope Reactor (HFIR), Oak Ridge National Laboratory at reactor coolant temperatures of 50–70 ?C to low displacement damage of 0.025 and 0.3 dpa. After cooling down, the HFIR neutronirradiated tungsten samples were exposed to deuterium plasmas in the Tritium Plasma Experiment, Idaho National Laboratory at 100, 200 and 500 ?C twice at the ion fluence of 5×1025 m-2 to reach the total ion fluence of 1×1026 m-2 in order to investigate maximum near-surface (<5µm depth) deuterium concentration increased from 0.5 at% D/W in 0.025 dpa samples to 0.8 at% D/W in 0.3 dpa samples. The large discrepancy between the total retention via thermal desorption spectroscopy and the nearsurface retention via nuclear reaction analysis indicated the deuterium was trapped in bulk (at least 50µm depth for 0.025 dpa and 35µm depth for 0.3 dpa) at 500 ?C cases even in the relatively low ion fluence of 1026 m-2.

  4. Prediction of human observer performance in a 2-alternative forced choice low-contrast detection task using channelized Hotelling observer: Impact of radiation dose and reconstruction algorithms

    SciTech Connect (OSTI)

    Yu Lifeng; Leng Shuai; Chen Lingyun; Kofler, James M.; McCollough, Cynthia H. [Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905 (United States); Carter, Rickey E. [Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota 55905 (United States)

    2013-04-15T23:59:59.000Z

    Purpose: Efficient optimization of CT protocols demands a quantitative approach to predicting human observer performance on specific tasks at various scan and reconstruction settings. The goal of this work was to investigate how well a channelized Hotelling observer (CHO) can predict human observer performance on 2-alternative forced choice (2AFC) lesion-detection tasks at various dose levels and two different reconstruction algorithms: a filtered-backprojection (FBP) and an iterative reconstruction (IR) method. Methods: A 35 Multiplication-Sign 26 cm{sup 2} torso-shaped phantom filled with water was used to simulate an average-sized patient. Three rods with different diameters (small: 3 mm; medium: 5 mm; large: 9 mm) were placed in the center region of the phantom to simulate small, medium, and large lesions. The contrast relative to background was -15 HU at 120 kV. The phantom was scanned 100 times using automatic exposure control each at 60, 120, 240, 360, and 480 quality reference mAs on a 128-slice scanner. After removing the three rods, the water phantom was again scanned 100 times to provide signal-absent background images at the exact same locations. By extracting regions of interest around the three rods and on the signal-absent images, the authors generated 21 2AFC studies. Each 2AFC study had 100 trials, with each trial consisting of a signal-present image and a signal-absent image side-by-side in randomized order. In total, 2100 trials were presented to both the model and human observers. Four medical physicists acted as human observers. For the model observer, the authors used a CHO with Gabor channels, which involves six channel passbands, five orientations, and two phases, leading to a total of 60 channels. The performance predicted by the CHO was compared with that obtained by four medical physicists at each 2AFC study. Results: The human and model observers were highly correlated at each dose level for each lesion size for both FBP and IR. The Pearson's product-moment correlation coefficients were 0.986 [95% confidence interval (CI): 0.958-0.996] for FBP and 0.985 (95% CI: 0.863-0.998) for IR. Bland-Altman plots showed excellent agreement for all dose levels and lesions sizes with a mean absolute difference of 1.0%{+-} 1.1% for FBP and 2.1%{+-} 3.3% for IR. Conclusions: Human observer performance on a 2AFC lesion detection task in CT with a uniform background can be accurately predicted by a CHO model observer at different radiation dose levels and for both FBP and IR methods.

  5. Iodine-131 releases from the Hanford Site, 1944--1947. Volume 1, Text: Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Heeb, C.M.

    1992-10-01T23:59:59.000Z

    Releases of fission product iodine-131 from separation plants at the Hanford reservation are calculated for the 1944 through 1947 period. Releases to the atmosphere were from the ventilation stacks of T and B separation plants. A reconstruction of daily separation plant operations forms the basis of the releases. The reconstruction traces the iodine-131 content of each fuel discharge from the B, D, and F Reactors to the dissolving step in the separation plants. Statistical computer modeling techniques are used to estimate hourly release histories based on sampling mathematical distribution functions that express the uncertainties in the source data and timing. The reported daily, monthly, and yearly estimates are averages and uncertainty ranges are based on 100 independent Monte Carlo ``realizations`` of the hourly release histories.

  6. Reconstructing the neutron-star equation of state with gravitational-wave detectors from a realistic population of inspiralling binary neutron stars

    E-Print Network [OSTI]

    Benjamin D. Lackey; Leslie Wade

    2014-10-31T23:59:59.000Z

    Gravitational-wave observations of inspiralling binary neutron star systems can be used to measure the neutron-star equation of state (EOS) through the tidally induced shift in the waveform phase that depends on the tidal deformability parameter $\\lambda$. Previous work has shown that $\\lambda$, a function of the neutron-star EOS and mass, is measurable by Advanced LIGO for a single event when including tidal information up to the merger frequency. In this work, we describe a method for stacking measurements of $\\lambda$ from multiple inspiral events to measure the EOS. We use Markov chain Monte Carlo simulations to estimate the parameters of a 4-parameter piecewise polytrope EOS that matches theoretical EOS models to a few percent. We find that, for "realistic" event rates ($\\sim 40$ binary neutron star inspiral events per year with signal-to-noise ratio $> 8$ in a single Advanced LIGO detector), combining a year of gravitational-wave data from a three-detector network with the constraints from causality and recent high mass neutron-star measurements, the EOS above nuclear density can be measured to better than a factor of two in pressure in most cases. We also find that in the mass range $1M_\\odot$--$2M_\\odot$, the neutron-star radius can be measured to better than $\\pm 1$ km and the tidal deformability can be measured to better than $\\pm 1 \\times 10^{36}$ g cm$^2$ s$^2$ (10%--50% depending on the EOS and mass). The overwhelming majority of this information comes from the loudest $\\sim 5$ events. Current uncertainties in the post-Newtonian waveform model, however, lead to systematic errors in the EOS measurement that are as large as the statistical errors, and more accurate waveform models are needed to minimize this error.

  7. Radioactive contamination of fish, shellfish, and waterfowl exposed to Hanford effluents: Annual summaries, 1945--1972. Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Hanf, R.W.; Dirkes, R.L.; Duncan, J.P.

    1992-07-01T23:59:59.000Z

    The objective of the Hanford Environmental Dose Reconstruction Project (HEDR) is to estimate the potential radiation doses received by people living within the sphere of influence of the Hanford Site. A potential critical pathway for human radiation exposure is through the consumption of waterfowl that frequent onsite waste-water ponds or through eating of fish, shellfish, and waterfowl that reside in/on the Columbia River and its tributaries downstream of the reactors. This document summarizes information on fish, shellfish, and waterfowl radiation contamination for samples collected by Hanford monitoring personnel and offsite agencies for the period 1945 to 1972. Specific information includes the types of organisms sampled, the kinds of tissues and organs analyzed, the sampling locations, and the radionuclides reported. Some tissue concentrations are also included. We anticipate that these yearly summaries will be helpful to individuals and organizations interested in evaluating aquatic pathway information for locations impacted by Hanford operations and will be useful for planning the direction of future HEDR studies.

  8. Dose reconstruction for the Urals population. Joint Coordinating Committee on Radiation Effects Research, Project 1.1 -- Final report

    SciTech Connect (OSTI)

    Degteva, M.O. [Urals Research Center for Radiation Medicine, Chelyabinsk (Russian Federation)] [Urals Research Center for Radiation Medicine, Chelyabinsk (Russian Federation); Drozhko, E. [Branch 1 of Moscow Biophysics Inst., Ozersk (Russian Federation)] [Branch 1 of Moscow Biophysics Inst., Ozersk (Russian Federation); Anspaugh, L.R. [Lawrence Livermore National Lab., CA (United States)] [Lawrence Livermore National Lab., CA (United States); Napier, B.A. [Pacific Northwest National Lab., Richland, WA (United States)] [Pacific Northwest National Lab., Richland, WA (United States); Bouville, A.C. [National Cancer Inst., Bethesda, MD (United States)] [National Cancer Inst., Bethesda, MD (United States); Miller, C.W. [Centers for Disease Control and Prevention, Atlanta, GA (United States)] [Centers for Disease Control and Prevention, Atlanta, GA (United States)

    1996-02-01T23:59:59.000Z

    This work is being carried out as a feasibility study to determine if a long-term course of work can be implemented to assess the long-term risks of radiation exposure delivered at low to moderate dose rates to the populations living in the vicinity of the Mayak Industrial Association (MIA). This work was authorized and conducted under the auspices of the US-Russian Joint Coordinating Committee on Radiation Effects Research (JCCRER) and its Executive Committee (EC). The MIA was the first Russian site for the production and separation of plutonium. This plant began operation in 1948, and during its early days there were technological failures that resulted in the release of large amounts of waste into the rather small Techa River. There were also gaseous releases of radioiodines and other radionuclides during the early days of operation. In addition, there was an accidental explosion in a waste storage tank in 1957 that resulted in a significant release. The Techa River Cohort has been studied for several years by scientists from the Urals Research Centre for Radiation Medicine and an increase in both leukemia and solid tumors has been noted.

  9. SU-E-J-100: Reconstruction of Prompt Gamma Ray Three Dimensional SPECT Image From Boron Neutron Capture Therapy(BNCT)

    SciTech Connect (OSTI)

    Yoon, D; Jung, J; Suh, T [The Catholic University of Korea, College of medicine, Department of biomedical engineering (Korea, Republic of)

    2014-06-01T23:59:59.000Z

    Purpose: Purpose of paper is to confirm the feasibility of acquisition of three dimensional single photon emission computed tomography (SPECT) image from boron neutron capture therapy (BNCT) using Monte Carlo simulation. Methods: In case of simulation, the pixelated SPECT detector, collimator and phantom were simulated using Monte Carlo n particle extended (MCNPX) simulation tool. A thermal neutron source (<1 eV) was used to react with the boron uptake region (BUR) in the phantom. Each geometry had a spherical pattern, and three different BURs (A, B and C region, density: 2.08 g/cm3) were located in the middle of the brain phantom. The data from 128 projections for each sorting process were used to achieve image reconstruction. The ordered subset expectation maximization (OSEM) reconstruction algorithm was used to obtain a tomographic image with eight subsets and five iterations. The receiver operating characteristic (ROC) curve analysis was used to evaluate the geometric accuracy of reconstructed image. Results: The OSEM image was compared with the original phantom pattern image. The area under the curve (AUC) was calculated as the gross area under each ROC curve. The three calculated AUC values were 0.738 (A region), 0.623 (B region), and 0.817 (C region). The differences between length of centers of two boron regions and distance of maximum count points were 0.3 cm, 1.6 cm and 1.4 cm. Conclusion: The possibility of extracting a 3D BNCT SPECT image was confirmed using the Monte Carlo simulation and OSEM algorithm. The prospects for obtaining an actual BNCT SPECT image were estimated from the quality of the simulated image and the simulation conditions. When multiple tumor region should be treated using the BNCT, a reasonable model to determine how many useful images can be obtained from the SPECT could be provided to the BNCT facilities. This research was supported by the Leading Foreign Research Institute Recruitment Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, Information and Communication Technologies (ICT) and Future Planning (MSIP)(Grant No.200900420) and the Radiation Technology Research and Development program (Grant No.2013043498), Republic of Korea.

  10. Use of international data sets to evaluate and validate pathway assessment models applicable to exposure and dose reconstruction at DOE facilities. Progress report, March--May 1994

    SciTech Connect (OSTI)

    Anspaugh, L.R.; Hendrickson, S.M. [eds.] [Lawrence Livermore National Lab., CA (United States); Hoffman, F.O. [Senes Oak Ridge, Inc., TN (United States). Center for Risk Analysis

    1994-06-01T23:59:59.000Z

    The project described in this report was the result of a Memorandum of Cooperation between the US and the former-USSR following the accident at the Chernobyl Nuclear Power Plant Unit 4. A joint program was established to improve the safety of nuclear power plants and to understand the implications of environmental releases. The task of Working Group 7 was ``to develop jointly methods to project rapidly the health effects of any future nuclear reactor accident.`` The current objective of this project is to evaluate and validate pathway-assessment models applicable to exposure and dose reconstruction at DOE facilities through use of international data sets. This project incorporates data used for the prediction of radionuclide transfer through agricultural and aquatic systems to humans. It also includes participation in two multinational studies, BIOMOVS (Biospheric Model Validation Study) with the Swedish National Institute for Radiation Protection and VAMP (Validation of Model Predictions) with the International Atomic Energy Agency, that address testing the performance of models of radionuclide transport through foodchains. In the future, this project will be considered separately from the Chernobyl Studies Project and the essential activities of former Task 7.1D will be folded within the broader umbrella of the BIOMOVS and VAMP projects. The Working Group Leader of Task 7.1D will continue to provide oversight for this project.

  11. Measurement of neutron spectra for determining dose equivalent rates at the Texas A&M University Nuclear Science Center

    E-Print Network [OSTI]

    Sanza, Bruce Jerome

    1986-01-01T23:59:59.000Z

    Helium-3 Proportional Counter LET Proportional Counter. METHOD. RESULTS AND DISCUSSION 14 . 15 17 21 25 Multispheres Helium-3 Proportional Counter LET Proportional Counter 25 . . . 30 32 VI CONCLUSIONS 39 REFERENCES. . 41 SUPPLEMENTAL... for performance of personnel neutron dosimeters is provided by the American National Standards Institute (ANSI76) and supplemented by the U. S. Nuclear Regulatory Commision (NRC77). These requirements are outlined in Table 1. The dosimeters available for use...

  12. High energy neutron dosimeter

    DOE Patents [OSTI]

    Sun, Rai Ko S.F. (Albany, CA)

    1994-01-01T23:59:59.000Z

    A device for measuring dose equivalents in neutron radiation fields. The device includes nested symmetrical hemispheres (forming spheres) of different neutron moderating materials that allow the measurement of dose equivalents from 0.025 eV to past 1 GeV. The layers of moderating material surround a spherical neutron counter. The neutron counter is connected by an electrical cable to an electrical sensing means which interprets the signal from the neutron counter in the center of the moderating spheres. The spherical shape of the device allows for accurate measurement of dose equivalents regardless of its positioning.

  13. High energy neutron dosimeter

    DOE Patents [OSTI]

    Rai, K.S.F.

    1994-01-11T23:59:59.000Z

    A device for measuring dose equivalents in neutron radiation fields is described. The device includes nested symmetrical hemispheres (forming spheres) of different neutron moderating materials that allow the measurement of dose equivalents from 0.025 eV to past 1 GeV. The layers of moderating material surround a spherical neutron counter. The neutron counter is connected by an electrical cable to an electrical sensing means which interprets the signal from the neutron counter in the center of the moderating spheres. The spherical shape of the device allows for accurate measurement of dose equivalents regardless of its positioning. 2 figures.

  14. Proton recoil scintillator neutron rem meter

    DOE Patents [OSTI]

    Olsher, Richard H. (Los Alamos, NM); Seagraves, David T. (Los Alamos, NM)

    2003-01-01T23:59:59.000Z

    A neutron rem meter utilizing proton recoil and thermal neutron scintillators to provide neutron detection and dose measurement. In using both fast scintillators and a thermal neutron scintillator the meter provides a wide range of sensitivity, uniform directional response, and uniform dose response. The scintillators output light to a photomultiplier tube that produces an electrical signal to an external neutron counter.

  15. Use of international data sets to evaluate and validate pathway assessment models applicable to exposure and dose reconstruction at DOE facilities. Monthly progress reports and final report, October--December 1994

    SciTech Connect (OSTI)

    Hoffman, F.O. [Senes Oak Ridge, Inc., TN (United States). Center for Risk Analysis

    1995-04-01T23:59:59.000Z

    The objective of Task 7.lD was to (1) establish a collaborative US-USSR effort to improve and validate our methods of forecasting doses and dose commitments from the direct contamination of food sources, and (2) perform experiments and validation studies to improve our ability to predict rapidly and accurately the long-term internal dose from the contamination of agricultural soil. At early times following an accident, the direct contamination of pasture and food stuffs, particularly leafy vegetation and grain, can be of great importance. This situation has been modeled extensively. However, models employed then to predict the deposition, retention and transport of radionuclides in terrestrial environments employed concepts and data bases that were more than a decade old. The extent to which these models have been tested with independent data sets was limited. The data gathered in the former-USSR (and elsewhere throughout the Northern Hemisphere) offered a unique opportunity to test model predictions of wet and dry deposition, agricultural foodchain bioaccumulation, and short- and long-term retention, redistribution, and resuspension of radionuclides from a variety of natural and artificial surfaces. The current objective of this project is to evaluate and validate pathway-assessment models applicable to exposure and dose reconstruction at DOE facilities through use of international data sets. This project incorporates the activity of Task 7.lD into a multinational effort to evaluate models and data used for the prediction of radionuclide transfer through agricultural and aquatic systems to humans. It also includes participation in two studies, BIOMOVS (BIOspheric MOdel Validation Study) with the Swedish National Institute for Radiation Protection and VAMP (VAlidation of Model Predictions) with the International Atomic Energy Agency, that address testing the performance of models of radionuclide transport through foodchains.

  16. Portable neutron spectrometer and dosimeter

    DOE Patents [OSTI]

    Waechter, David A. (Los Alamos, NM); Erkkila, Bruce H. (Los Alamos, NM); Vasilik, Dennis G. (Los Alamos, NM)

    1985-01-01T23:59:59.000Z

    The disclosure relates to a battery operated neutron spectrometer/dosimeter utilizing a microprocessor, a built-in tissue equivalent LET neutron detector, and a 128-channel pulse height analyzer with integral liquid crystal display. The apparatus calculates doses and dose rates from neutrons incident on the detector and displays a spectrum of rad or rem as a function of keV per micron of equivalent tissue and also calculates and displays accumulated dose in millirads and millirem as well as neutron dose rates in millirads per hour and millirem per hour.

  17. Prediction of proton and neutron absorbed-dose distributions in proton beam radiation therapy using Monte Carlo n-particle transport code (MCNPX)

    E-Print Network [OSTI]

    Massingill, Brian Edward

    2009-05-15T23:59:59.000Z

    The objective of this research was to develop a complex MCNPX model of the human head to predict absorbed dose distributions during proton therapy of ocular tumors. Absorbed dose distributions using the complex geometry were compared to a simple...

  18. Prediction of proton and neutron absorbed-dose distributions in proton beam radiation therapy using Monte Carlo n-particle transport code (MCNPX) 

    E-Print Network [OSTI]

    Massingill, Brian Edward

    2009-05-15T23:59:59.000Z

    The objective of this research was to develop a complex MCNPX model of the human head to predict absorbed dose distributions during proton therapy of ocular tumors. Absorbed dose distributions using the complex geometry were compared to a simple...

  19. Database of radionuclide measurements in Columbia River water, fish, waterfowl, gamebirds, and shellfish downstream of Hanford`s single-pass production reactors, 1960--1970. Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Thiede, M.E.; Duncan, J.P.

    1994-03-01T23:59:59.000Z

    This report is a result of the Hanford Environmental Dose Reconstruction (HEDR) Project. The goal of the HEDR Project is to estimate the radiation dose that individuals could have received from radionuclide emissions since 1944 at the Hanford Site near Richland, Washington. The HEDR Project is conducted by Battelle, Pacific Northwest Laboratories. The time periods of greatest interest to the HEDR study vary depending on the type of environmental media concerned. Concentrations of radionuclides in Columbia River media from 1960--1970 provide the best historical data for validation of the Columbia River pathway computer models. This report provides the historical radionuclide measurements in Columbia River water (1960--1970), fish (1960--1967), waterfowl (1960--1970), gamebirds (1967--1970), and shellfish (1960--1970). Because of the large size of the databases (845 pages), this report is being published on diskette. A diskette of this report is available from the Technical Steering Panel (c/o K. CharLee, Office of Nuclear Waste Management, Department of Ecology, Technical Support and Publication Information Section, P.O. Box 47651, Olympia, Washington 98504-7651).

  20. Experimental Component Characterization, Monte-Carlo-Based Image Generation and Source Reconstruction for the Neutron Imaging System of the National Ignition Facility

    SciTech Connect (OSTI)

    Barrera, C A; Moran, M J

    2007-08-21T23:59:59.000Z

    The Neutron Imaging System (NIS) is one of seven ignition target diagnostics under development for the National Ignition Facility. The NIS is required to record hot-spot (13-15 MeV) and downscattered (6-10 MeV) images with a resolution of 10 microns and a signal-to-noise ratio (SNR) of 10 at the 20% contour. The NIS is a valuable diagnostic since the downscattered neutrons reveal the spatial distribution of the cold fuel during an ignition attempt, providing important information in the case of a failed implosion. The present study explores the parameter space of several line-of-sight (LOS) configurations that could serve as the basis for the final design. Six commercially available organic scintillators were experimentally characterized for their light emission decay profile and neutron sensitivity. The samples showed a long lived decay component that makes direct recording of a downscattered image impossible. The two best candidates for the NIS detector material are: EJ232 (BC422) plastic fibers or capillaries filled with EJ399B. A Monte Carlo-based end-to-end model of the NIS was developed to study the imaging capabilities of several LOS configurations and verify that the recovered sources meet the design requirements. The model includes accurate neutron source distributions, aperture geometries (square pinhole, triangular wedge, mini-penumbral, annular and penumbral), their point spread functions, and a pixelated scintillator detector. The modeling results show that a useful downscattered image can be obtained by recording the primary peak and the downscattered images, and then subtracting a decayed version of the former from the latter. The difference images need to be deconvolved in order to obtain accurate source distributions. The images are processed using a frequency-space modified-regularization algorithm and low-pass filtering. The resolution and SNR of these sources are quantified by using two surrogate sources. The simulations show that all LOS configurations have a resolution of 7 microns or better. The 28 m LOS with a 7 x 7 array of 100-micron mini-penumbral apertures or 50-micron square pinholes meets the design requirements and is a very good design alternative.

  1. Secondary neutrons in clinical proton radiotherapy: A charged issue

    E-Print Network [OSTI]

    Brenner, David Jonathan

    -body neutron dose, due to interactions of the protons with the scattering and collimating beam elements radiotherapy; Secondary neutrons; Second cancers; Passive scattering The development of hospital-based proton on establishing the neutron doses involved [7­20], there is still no agree- ment about whether these scattered

  2. Neutronic reactor

    DOE Patents [OSTI]

    Wende, Charles W. J. (Augusta, GA); Babcock, Dale F. (Wilmington, DE); Menegus, Robert L. (Wilmington, DE)

    1983-01-01T23:59:59.000Z

    A nuclear reactor includes an active portion with fissionable fuel and neutron moderating material surrounded by neutron reflecting material. A control element in the active portion includes a group of movable rods constructed of neutron-absorbing material. Each rod is movable with respect to the other rods to vary the absorption of neutrons and effect control over neutron flux.

  3. Neutron tube design study for boron neutron capture therapy application

    SciTech Connect (OSTI)

    Verbeke, J.M.; Lee, Y.; Leung, K.N.; Vujic, J.; Williams, M.D.; Wu, L.K.; Zahir, N.

    1999-05-06T23:59:59.000Z

    Radio-frequency (RF) driven ion sources are being developed in Lawrence Berkeley National Laboratory (LBNL) for sealed-accelerator-tube neutron generator application. By using a 5-cm-diameter RF-driven multicusp source H{sup +} yields over 95% have been achieved. These experimental findings will enable one to develop compact neutron generators based on the D-D or D-T fusion reactions. In this new neutron generator, the ion source, the accelerator and the target are all housed in a sealed metal container without external pumping. Recent moderator design simulation studies have shown that 14 MeV neutrons could be moderated to therapeutically useful energy ranges for boron neutron capture therapy (BNCT). The dose near the center of the brain with optimized moderators is about 65% higher than the dose obtained from a typical neutron spectrum produced by the Brookhaven Medical Research Reactor (BMRR), and is comparable to the dose obtained by other accelerator-based neutron sources. With a 120 keV and 1 A deuteron beam, a treatment time of {approx}35 minutes is estimated for BNCT.

  4. Hierarchical regularization for edge-preserving reconstruction of PET images

    E-Print Network [OSTI]

    Bardsley, John

    Hierarchical regularization for edge-preserving reconstruction of PET images Johnathan M. Bardsley.somersalo@case.edu Abstract. The data in PET emission and transmission tomography and in low dose X-ray tomography, consists that the algorithm gives good quality reconstructions for both emission and transmission PET problems in an efficient

  5. Personnel electronic neutron dosimeter

    DOE Patents [OSTI]

    Falk, Roger B. (Lafayette, CO); Tyree, William H. (Boulder, CO)

    1984-12-18T23:59:59.000Z

    A personnel electronic dosimeter includes a neutron-proton and neutron-alpha converter for providing an electrical signal having a magnitude proportional to the energy of a detected proton or alpha particle produced from the converter, a pulse generator circuit for generating a pulse having a duration controlled by the weighed effect of the amplitude of the electrical signal, an oscillator enabled by the pulse for generating a train of clock pulses for a time dependent upon the pulse length, a counter for counting the clock pulses, and an indicator for providing a direct reading and aural alarm when the count indicates that the wearer has been exposed to a selected level of neutron dose equivalent.

  6. Personnel electronic neutron dosimeter

    DOE Patents [OSTI]

    Falk, R.B.; Tyree, W.H.

    1982-03-03T23:59:59.000Z

    A personnel electronic dosimeter includes a neutron-proton and neutron-alpha converter for providing an electrical signal having a magnitude proportional to the energy of a detected proton or alpha particle produced from the converter, a pulse generator circuit for generating a pulse having a duration controlled by the weighed effect of the amplitude of the electrical signal, an oscillator enabled by the pulse for generating a train of clock pulses for a time dependent upon the pulse length, a counter for counting the clock pulses, and an indicator for providing a direct reading and aural alarm when the count indicates that the wearer has been exposed to a selected level of neutron dose equivalent.

  7. Computer simulation of neutron capture therapy.

    E-Print Network [OSTI]

    Olson, Arne Peter

    1967-01-01T23:59:59.000Z

    Analytical methods are developed to simulate on a large digital computer the production and use of reactor neutron beams f or boron capture therapy of brain tumors. The simulation accounts for radiation dose distributions ...

  8. Computer simulation of neutron capture therapy

    E-Print Network [OSTI]

    Olson, Arne Peter

    1967-01-01T23:59:59.000Z

    Analytical methods are developed to simulate on a large digital computer the production and use of reactor neutron beams f or boron capture therapy of brain tumors. The simulation accounts for radiation dose distributions ...

  9. Neutron skins and neutron stars

    SciTech Connect (OSTI)

    Piekarewicz, J. [Department of Physics, Florida State University, Tallahassee, FL 32306-4350 (United States)

    2013-11-07T23:59:59.000Z

    The neutron-skin thickness of heavy nuclei provides a fundamental link to the equation of state of neutron-rich matter, and hence to the properties of neutron stars. The Lead Radius Experiment ('PREX') at Jefferson Laboratory has recently provided the first model-independence evidence on the existence of a neutron-rich skin in {sup 208}Pb. In this contribution we examine how the increased accuracy in the determination of neutron skins expected from the commissioning of intense polarized electron beams may impact the physics of neutron stars.

  10. Neutron guide

    DOE Patents [OSTI]

    Greene, Geoffrey L. (Los Alamos, NM)

    1999-01-01T23:59:59.000Z

    A neutron guide in which lengths of cylindrical glass tubing have rectangular glass plates properly dimensioned to allow insertion into the cylindrical glass tubing so that a sealed geometrically precise polygonal cross-section is formed in the cylindrical glass tubing. The neutron guide provides easier alignment between adjacent sections than do the neutron guides of the prior art.

  11. Study on neutron radiation field of carbon ions therapy

    E-Print Network [OSTI]

    Xu, Jun-Kui; Li, Wu-Yuan; Yan, Wei-Wei; Chen, Xi-Meng; Mao, Wang; Pang, Cheng-Guo

    2015-01-01T23:59:59.000Z

    Carbon ions offer significant advantages for deep-seated local tumors therapy due to their physical and biological properties. Secondary particles, especially neutrons caused by heavy ion reactions should be carefully considered in treatment process and radiation protection. For radiation protection purposes, the FLUKA Code was used in order to evaluate the radiation field at deep tumor therapy room of HIRFL in this paper. The neutron energy spectra, neutron dose and energy deposition of carbon ion and neutron in tissue-like media was studied for bombardment of solid water target by 430MeV/u C ions. It is found that the calculated neutron dose have a good agreement with the experimental date, and the secondary neutron dose may not exceed one in a thousand of the carbon ions dose at Bragg peak area in tissue-like media.

  12. Neutron Scattering Tutorials | Neutron Science | ORNL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Neutron Scattering Tutorials SHARE Neutron Scattering Tutorials The following lectures were presented at the 2011 and 2010 National School on Neutron & X-Ray Scattering. This...

  13. Neutron detector

    DOE Patents [OSTI]

    Stephan, Andrew C. (Knoxville, TN); Jardret; Vincent D. (Powell, TN)

    2011-04-05T23:59:59.000Z

    A neutron detector has a volume of neutron moderating material and a plurality of individual neutron sensing elements dispersed at selected locations throughout the moderator, and particularly arranged so that some of the detecting elements are closer to the surface of the moderator assembly and others are more deeply embedded. The arrangement captures some thermalized neutrons that might otherwise be scattered away from a single, centrally located detector element. Different geometrical arrangements may be used while preserving its fundamental characteristics. Different types of neutron sensing elements may be used, which may operate on any of a number of physical principles to perform the function of sensing a neutron, either by a capture or a scattering reaction, and converting that reaction to a detectable signal. High detection efficiency, an ability to acquire spectral information, and directional sensitivity may be obtained.

  14. Lithium-6 filter for a fission converter-based Boron Neutron Capture Therapy irradiation facility beam

    E-Print Network [OSTI]

    Gao, Wei, Ph. D.

    2005-01-01T23:59:59.000Z

    (cont.) A storage system was designed to contain the lithium-6 filter safely when it is not in use. A mixed field dosimetry method was used to measure the photon, thermal neutron and fast neutron dose. The measured advantage ...

  15. Neutron tubes

    DOE Patents [OSTI]

    Leung, Ka-Ngo (Hercules, CA); Lou, Tak Pui (Berkeley, CA); Reijonen, Jani (Oakland, CA)

    2008-03-11T23:59:59.000Z

    A neutron tube or generator is based on a RF driven plasma ion source having a quartz or other chamber surrounded by an external RF antenna. A deuterium or mixed deuterium/tritium (or even just a tritium) plasma is generated in the chamber and D or D/T (or T) ions are extracted from the plasma. A neutron generating target is positioned so that the ion beam is incident thereon and loads the target. Incident ions cause D-D or D-T (or T-T) reactions which generate neutrons. Various embodiments differ primarily in size of the chamber and position and shape of the neutron generating target. Some neutron generators are small enough for implantation in the body. The target may be at the end of a catheter-like drift tube. The target may have a tapered or conical surface to increase target surface area.

  16. Oak Ridge Health Studies Phase 1 report, Volume 2: Part A, Dose Reconstruction Feasibility Study. Tasks 1 and 2, A summary of historical activities on the Oak Ridge Reservation with emphasis on information concerning off-site emissions of hazardous materials

    SciTech Connect (OSTI)

    Bruce, G.M.; Buddenbaum, J.E.; Lamb, J.K.; Widner, T.E.

    1993-09-01T23:59:59.000Z

    The Phase I feasibility study has focused on determining the availability of information for estimating exposures of the public to chemicals and radionuclides released as a result of historical operation of the facilities at the Oak Ridge Reservation (ORR). The estimation of such past exposures is frequently called dose reconstruction. The initial project tasks, Tasks 1 and 2 were designed to identify and collect information that documents the history of activities at the ORR that resulted in the release of contamination and to characterize the availability of data that could be used to estimate the magnitude of the contaminant releases or public exposures. A history of operations that are likely to have generated off-site releases has been documented as a result of Task 1 activities. The activities required to perform this task involved the extensive review of historical operation records and interviews with present and past employees as well as other knowledgeable individuals. The investigation process is documented in this report. The Task 1 investigations have led to the documentation of an overview of the activities that have taken place at each of the major complexes, including routine operations, waste management practices, special projects, and accidents and incidents. Historical activities that appear to warrant the highest priority in any further investigations were identified based on their likely association with off-site emissions of hazardous materials as indicated by the documentation reviewed or information obtained in interviews.

  17. Ptychographic ultrafast pulse reconstruction

    E-Print Network [OSTI]

    Spangenberg, D; Brügmann, M H; Feurer, T

    2014-01-01T23:59:59.000Z

    We demonstrate a new ultrafast pulse reconstruction modality which is somewhat reminiscent of frequency resolved optical gating but uses a modified setup and a conceptually different reconstruction algorithm that is derived from ptychography. Even though it is a second order correlation scheme it shows no time ambiguity. Moreover, the number of spectra to record is considerably smaller than in most other related schemes which, together with a robust algorithm, leads to extremely fast convergence of the reconstruction.

  18. Thermal neutron detection system

    DOE Patents [OSTI]

    Peurrung, Anthony J. (Richland, WA); Stromswold, David C. (West Richland, WA)

    2000-01-01T23:59:59.000Z

    According to the present invention, a system for measuring a thermal neutron emission from a neutron source, has a reflector/moderator proximate the neutron source that reflects and moderates neutrons from the neutron source. The reflector/moderator further directs thermal neutrons toward an unmoderated thermal neutron detector.

  19. Design of a boron neutron capture enhanced fast neutron therapy assembly

    SciTech Connect (OSTI)

    Wang, Zhonglu; /Georgia Tech

    2006-08-01T23:59:59.000Z

    The use of boron neutron capture to boost tumor dose in fast neutron therapy has been investigated at several fast neutron therapy centers worldwide. This treatment is termed boron neutron capture enhanced fast neutron therapy (BNCEFNT). It is a combination of boron neutron capture therapy (BNCT) and fast neutron therapy (FNT). It is believed that BNCEFNT may be useful in the treatment of some radioresistant brain tumors, such as glioblastoma multiform (GBM). A boron neutron capture enhanced fast neutron therapy assembly has been designed for the Fermilab Neutron Therapy Facility (NTF). This assembly uses a tungsten filter and collimator near the patient's head, with a graphite reflector surrounding the head to significantly increase the dose due to boron neutron capture reactions. The assembly was designed using Monte Carlo radiation transport code MCNP version 5 for a standard 20x20 cm{sup 2} treatment beam. The calculated boron dose enhancement at 5.7-cm depth in a water-filled head phantom in the assembly with a 5x5 cm{sup 2} collimation was 21.9% per 100-ppm {sup 10}B for a 5.0-cm tungsten filter and 29.8% for a 8.5-cm tungsten filter. The corresponding dose rate for the 5.0-cm and 8.5-cm thick filters were 0.221 and 0.127 Gy/min, respectively; about 48.5% and 27.9% of the dose rate of the standard 10x10 cm{sup 2} fast neutron treatment beam. To validate the design calculations, a simplified BNCEFNT assembly was built using four lead bricks to form a 5x5 cm{sup 2} collimator. Five 1.0-cm thick 20x20 cm{sup 2} tungsten plates were used to obtain different filter thicknesses and graphite bricks/blocks were used to form a reflector. Measurements of the dose enhancement of the simplified assembly in a water-filled head phantom were performed using a pair of tissue-equivalent ion chambers. One of the ion chambers is loaded with 1000-ppm natural boron (184-ppm {sup 10}B) to measure dose due to boron neutron capture. The measured dose enhancement at 5.0-cm depth in the head phantom for the 5.0-cm thick tungsten filter is (16.6 {+-} 1.8)%, which agrees well with the MCNP simulation of the simplified BNCEFNT assembly, (16.4 {+-} 0.5)%. The error in the calculated dose enhancement only considers the statistical uncertainties. The total dose rate measured at 5.0-cm depth using the non-borated ion chamber is (0.765 {+-} 0.076) Gy/MU, about 61% of the fast neutron standard dose rate (1.255Gy/MU) at 5.0-cm depth for the standard 10x10 cm{sup 2} treatment beam. The increased doses to other organs due to the use of the BNCEFNT assembly were calculated using MCNP5 and a MIRD phantom. The activities of the activation products produced in the BNCEFNT assembly after neutron beam delivery were computed. The photon ambient dose rate due to the radioactive activation products was also estimated.

  20. Internal dose following a major nuclear war

    SciTech Connect (OSTI)

    Peterson, K.R.; Shapiro, C.S. (Lawrence Livermore National Laboratory, Livermore, CA (Unites States))

    1992-01-01T23:59:59.000Z

    The PATHWAY model results were used, in conjunction with a hypothetical major nuclear attack on the U.S., to arrive at the ratio of internal to external dose for humans from early (48 h) fallout. Considered were the four nuclides (137Cs, 89Sr, 90Sr, 131I) that account for most of the reconstructed whole-body committed equivalent dose from internal radiation in people who lived downwind of the Nevada Test Site during atmospheric tests. Effects of climate perturbations (the 'nuclear winter' effect) on food crops were considered. These could increase internal dose estimates, depending on the severity of the climate perturbations. Internal and external doses to humans for 10 locations within the U.S. have been calculated, with varying local conditions and varying assumption about their shelters. The estimated 50-y internal dose commitment ranged from 0.0-0.17 Sv, the 48-h external dose from 0.15-4.6 Sv. The resultant ratios of internal to external committed dose received in the first months (until food transport was restored) varied from less than 0.01 to about 0.2. In all cases examined, the total dose from early fallout was found to be dominated by the external dose.

  1. Neutron range spectrometer

    DOE Patents [OSTI]

    Manglos, S.H.

    1988-03-10T23:59:59.000Z

    A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are colliminated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. 1 fig.

  2. Radiation damage by neutrons to plastic scintillators

    SciTech Connect (OSTI)

    Buss, G.; Dannemann, A.; Holm, U.; Wick, K. [Univ. Hamburg (Germany). Inst. fuer Experimentalphysik] [Univ. Hamburg (Germany). Inst. fuer Experimentalphysik

    1995-08-01T23:59:59.000Z

    Polystyrene based scintillator SCSN38, wavelength shifter Y7 with polymethylmethacrylate matrix and pure PM-MA light guide GS218 have been irradiated in the mixed radiation field of a pool reactor. About 77% of the dose released in SCSN38 was caused by the {gamma}-field, 23% by fast neutrons. The total dose ranged from 2 to 105 kGy. The dose measurements were made using alanine dosimeters. Transmission and fluorescence of the samples have been measured before and several times after irradiation. The radiation damage results shown o differences to irradiations in pure {gamma}-fields with corresponding released doses.

  3. Jet Reconstruction at RHIC

    E-Print Network [OSTI]

    Sevil Salur; for the STAR Collaboration

    2010-05-14T23:59:59.000Z

    Full jet reconstruction in heavy-ion collisions is expected to provide more sensitive measurements of jet quenching in hot QCD matter at RHIC. In this paper we review recent studies of jets utilizing modern jet reconstruction algorithms and their corresponding background subtraction techniques.

  4. Technical Reports Ultra-low Dose Lung CT Perfusion Regularized by

    E-Print Network [OSTI]

    Virginia Tech

    Technical Reports Ultra-low Dose Lung CT Perfusion Regularized by a Previous Scan1 Hengyong Yu, Ph­regularized reconstruction (PSRR) method was proposed to reduce radiation dose and applied to lung perfusion studies. Normal and ultra-low-dose lung computed tomographic perfusion studies were compared in terms of the estimation

  5. CAT reconstruction and potting comparison of a LMFBR fuel bundle

    SciTech Connect (OSTI)

    Betten, P.R.; Tow, D.M.

    1984-04-01T23:59:59.000Z

    A standard Liquid Metal Fast Breeder Reactor (LMFBR) subassembly used in the Experimental Breeder Reactor II (EBR-II) was investigated, by remote techniques, for fuel bundle distortion by both nondestructive and destructive methods, and the results from both methods were compared. The non-destructive method employed neutron tomography to reconstruct the locations of fuel elements through the use of a maximum entropy reconstruction algorithm known as MENT. The destructive method consisted of ''potting'' (a technique that embeds and permanently fixes the fuel elements in a solid matrix) the subassembly, and then cutting and polishing the individual sections. The comparison indicated that the tomography reconstruction provided good results in describing the bundle geometry and spacer-wire locations, with the overall resolution being on the order of a spacer-wire diameter. A dimensional consistency check indicated that the element and spacer-wire dimensions were accurately reproduced in the reconstruction.

  6. Improving neutron dosimetry using bubble detector technology

    SciTech Connect (OSTI)

    Buckner, M.A.

    1993-02-01T23:59:59.000Z

    Providing accurate neutron dosimetry for a variety of neutron energy spectra is a formidable task for any dosimetry system. Unless something is known about the neutron spectrum prior to processing the dosimeter, the calculated dose may vary greatly from that actually encountered; that is until now. The entrance of bubble detector technology into the field of neutron dosimetry has eliminated the necessity of having an a priori knowledge of the neutron energy spectra. Recently, a new approach in measuring personnel neutron dose equivalent was developed at Oak Ridge National Laboratory. By using bubble detectors in combination with current thermoluminescent dosimeters (TLDs) as a Combination Personnel Neutron Dosimeter (CPND), not only is it possible to provide accurate dose equivalent results, but a simple four-interval neutron energy spectrum is obtained as well. The components of the CPND are a Harshaw albedo TLD and two bubble detectors with theoretical energy thresholds of 100 key and 1500 keV. Presented are (1) a synoptic history surrounding emergence of bubble detector technology, (2) a brief overview of the current theory on mechanisms of interaction, (3) the data and analysis process involved in refining the response functions, (4) performance evaluation of the original CPND and a reevaluation of the same data under the modified method, (5) the procedure used to determine the reference values of component fluence and dose equivalent for field assessment, (6) analysis of the after-modification results, (7) a critique of some currently held assumptions, offering some alternative explanations, and (8) thoughts concerning potential applications and directions for future research.

  7. Computational aspects of treatment planning for neutron capture therapy

    E-Print Network [OSTI]

    Albritton, James Raymond, 1977-

    2010-01-01T23:59:59.000Z

    Boron Neutron Capture Therapy (BNCT) is a biochemically targeted form of binary radiation therapy that has the potential to deliver radiation to cancers with cellular dose selectivity. Accurate and efficient treatment ...

  8. Neutron Repulsion

    E-Print Network [OSTI]

    Oliver K. Manuel

    2011-02-08T23:59:59.000Z

    Earth is connected gravitationally, magnetically and electrically to its heat source - a neutron star that is obscured from view by waste products in the photosphere. Neutron repulsion is like the hot filament in an incandescent light bulb. Excited neutrons are emitted from the solar core and decay into hydrogen that glows in the photosphere like a frosted light bulb. Neutron repulsion was recognized in nuclear rest mass data in 2000 as the overlooked source of energy, the keystone of an arch that locked together these puzzling space-age observations: 1.) Excess 136Xe accompanied primordial helium in the stellar debris that formed the solar system (Fig. 1); 2.) The Sun formed on the supernova core (Fig. 2); 3.) Waste products from the core pass through an iron-rich mantle, selectively carrying lighter elements and lighter isotopes of each element into the photosphere (Figs. 3-4); and 4.) Neutron repulsion powers the Sun and sustains life (Figs. 5-7). Together these findings offer a framework for understanding how: a.) The Sun generates and releases neutrinos, energy and solar-wind hydrogen and helium; b.) An inhabitable planet formed and life evolved around an ordinary-looking star; c.) Continuous climate change - induced by cyclic changes in gravitational interactions of the Sun's energetic core with planets - has favored survival by adaptation.

  9. Neutron Repulsion

    E-Print Network [OSTI]

    Manuel, Oliver K

    2011-01-01T23:59:59.000Z

    Earth is connected gravitationally, magnetically and electrically to its heat source - a neutron star that is obscured from view by waste products in the photosphere. Neutron repulsion is like the hot filament in an incandescent light bulb. Excited neutrons are emitted from the solar core and decay into hydrogen that glows in the photosphere like a frosted light bulb. Neutron repulsion was recognized in nuclear rest mass data in 2000 as the overlooked source of energy, the keystone of an arch that locked together these puzzling space-age observations: 1.) Excess 136Xe accompanied primordial helium in the stellar debris that formed the solar system (Fig. 1); 2.) The Sun formed on the supernova core (Fig. 2); 3.) Waste products from the core pass through an iron-rich mantle, selectively carrying lighter elements and lighter isotopes of each element into the photosphere (Figs. 3-4); and 4.) Neutron repulsion powers the Sun and sustains life (Figs. 5-7). Together these findings offer a framework for understanding...

  10. Overview of Image Reconstruction

    SciTech Connect (OSTI)

    Marr, R.B.

    1980-04-01T23:59:59.000Z

    Image reconstruction (or computerized tomography, etc.) is any process whereby a function, f, on Rn is estimated from empirical data pertaining to its integrals, ∫f(x) dx, for some collection of hyperplanes of dimension k < n. The paper begins with background information on how image reconstruction problems have arisen in practice, and describes some of the application areas of past or current interest; these include radioastronomy, optics, radiology and nuclear medicine, electron microscopy, acoustical imaging, geophysical tomography, nondestructive testing, and NMR zeugmatography. Then the various reconstruction algorithms are discussed in five classes: summation, or simple back-projection; convolution, or filtered back-projection; Fourier and other functional transforms; orthogonal function series expansion; and iterative methods. Certain more technical mathematical aspects of image reconstruction are considered from the standpoint of uniqueness, consistency, and stability of solution. The paper concludes by presenting certain open problems. 73 references. (RWR)

  11. Reconstruction algorithms for MRI

    E-Print Network [OSTI]

    Bilgic?, Berkin

    2013-01-01T23:59:59.000Z

    This dissertation presents image reconstruction algorithms for Magnetic Resonance Imaging (MRI) that aims to increase the imaging efficiency. Algorithms that reduce imaging time without sacrificing the image quality and ...

  12. Reconstructing Cortical Dynamics with Magnetoencephalography

    E-Print Network [OSTI]

    Dalal, Sarang S.

    2007-01-01T23:59:59.000Z

    of adequately validated meth- ods for reconstructing suchdevelopment of statistical meth- ods used in this chapter,

  13. Fast neutron transmission spectroscopy for illicit substance detection

    SciTech Connect (OSTI)

    Yule, T.J.; Micklich, B.J.; Fink, C.L.; Sagalovsky, L.

    1996-05-01T23:59:59.000Z

    Fast Neutron Transmission Spectroscopy (FNTS) is being investigated for detecting explosives in luggage and other small containers. It uses an accelerator to generate nanosecond-pulsed neutron beams that strike a target, producing a white source of neutrons. Elemental distributions along projections through the interrogated object are obtained by analyzing neutron transmission data. Tomographic reconstruction is used to determine the spatial variations of individual elemental densities. Elemental densities are combined in a detection algorithm that indicates presence or absence of explosives. The elemental unfolding and tomographic reconstruction algorithms have been validated by application to experimental data. System studies have been performed to study the operational characteristics and limitations of a FNTS system, and to determine the system`s sensitivity to several important parameters such as flight path length and position of the interrogated object.

  14. Methods for absorbing neutrons

    DOE Patents [OSTI]

    Guillen, Donna P. (Idaho Falls, ID); Longhurst, Glen R. (Idaho Falls, ID); Porter, Douglas L. (Idaho Falls, ID); Parry, James R. (Idaho Falls, ID)

    2012-07-24T23:59:59.000Z

    A conduction cooled neutron absorber may include a metal matrix composite that comprises a metal having a thermal neutron cross-section of at least about 50 barns and a metal having a thermal conductivity of at least about 1 W/cmK. Apparatus for providing a neutron flux having a high fast-to-thermal neutron ratio may include a source of neutrons that produces fast neutrons and thermal neutrons. A neutron absorber positioned adjacent the neutron source absorbs at least some of the thermal neutrons so that a region adjacent the neutron absorber has a fast-to-thermal neutron ratio of at least about 15. A coolant in thermal contact with the neutron absorber removes heat from the neutron absorber.

  15. Neutron reflecting supermirror structure

    DOE Patents [OSTI]

    Wood, James L. (Drayton Plains, MI)

    1992-01-01T23:59:59.000Z

    An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources.

  16. Neutron reflecting supermirror structure

    DOE Patents [OSTI]

    Wood, J.L.

    1992-12-01T23:59:59.000Z

    An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. 2 figs.

  17. Characterization of a neutron calibration range 

    E-Print Network [OSTI]

    Menchaca, Daniel Isidoro

    1995-01-01T23:59:59.000Z

    182 N/A N/A N/A 33 CONCLUSIONS The computation of theoretical dose equivalent rate as a function of distance from the neutron source is substantially lower than the measured result from either the Andersson-Braun or the Rossi chamber...

  18. Deuterium density profile determination at JET using a neutron camera and a neutron spectrometer

    SciTech Connect (OSTI)

    Eriksson, J., E-mail: jacob.eriksson@physics.uu.se; Castegnetti, G.; Conroy, S.; Ericsson, G.; Hellesen, C. [EURATOM-VR, Department of Physics and Astronomy, Uppsala University (Sweden); Giacomelli, L. [Department of Physics, Università degli Studi di Milano-Bicocca, Milano (Italy); EURATOM-CCFE Fusion Association, Culham Science Centre, Abingdon (United Kingdom)

    2014-11-15T23:59:59.000Z

    In this work we estimate the fuel ion density profile in deuterium plasmas at JET, using the JET neutron camera, the neutron time-of-flight spectrometer TOFOR, and fusion reactivities modeled by the transport code TRANSP. The framework has been tested using synthetic data, which showed that the density profile could be reconstructed with an average accuracy of the order of 10 %. The method has also been applied to neutron measurements from a neutral beam heated JET discharge, which gave n{sub d}/n{sub e} ? 0.6 ± 0.3 in the plasma core and n{sub d}/n{sub e} ? 0.4 ± 0.3 towards the edge. Correction factors for detector efficiencies, neutron attenuation, and back-scattering are not yet included in the analysis; future work will aim at refining the estimated density.

  19. Fast neutron environments.

    SciTech Connect (OSTI)

    Buchheit, Thomas Edward; Kotula, Paul Gabriel; Lu, Ping; Brewer, Luke N. (Naval Postgraduate School, Monterey, CA); Goods, Steven Howard (Sandia National Laboratories, Livermore, CA); Foiles, Stephen Martin; Puskar, Joseph David; Hattar, Khalid Mikhiel; Doyle, Barney Lee; Boyce, Brad Lee; Clark, Blythe G.

    2011-10-01T23:59:59.000Z

    The goal of this LDRD project is to develop a rapid first-order experimental procedure for the testing of advanced cladding materials that may be considered for generation IV nuclear reactors. In order to investigate this, a technique was developed to expose the coupons of potential materials to high displacement damage at elevated temperatures to simulate the neutron environment expected in Generation IV reactors. This was completed through a high temperature high-energy heavy-ion implantation. The mechanical properties of the ion irradiated region were tested by either micropillar compression or nanoindentation to determine the local properties, as a function of the implantation dose and exposure temperature. In order to directly compare the microstructural evolution and property degradation from the accelerated testing and classical neutron testing, 316L, 409, and 420 stainless steels were tested. In addition, two sets of diffusion couples from 316L and HT9 stainless steels with various refractory metals. This study has shown that if the ion irradiation size scale is taken into consideration when developing and analyzing the mechanical property data, significant insight into the structural properties of the potential cladding materials can be gained in about a week.

  20. Technical Review of SRS Dose Reconstrruction Methods Used By CDC

    SciTech Connect (OSTI)

    Simpkins, Ali, A

    2005-07-20T23:59:59.000Z

    At the request of the Centers for Disease Control and Prevention (CDC), a subcontractor Advanced Technologies and Laboratories International, Inc.(ATL) issued a draft report estimating offsite dose as a result of Savannah River Site operations for the period 1954-1992 in support of Phase III of the SRS Dose Reconstruction Project. The doses reported by ATL differed than those previously estimated by Savannah River Site SRS dose modelers for a variety of reasons, but primarily because (1) ATL used different source terms, (2) ATL considered trespasser/poacher scenarios and (3) ATL did not consistently use site-specific parameters or correct usage parameters. The receptors with the highest dose from atmospheric and liquid pathways were within about a factor of four greater than dose values previously reported by SRS. A complete set of technical comments have also been included.

  1. An evaluation of stray neutron interference with routine thermoluminescent dosimetry

    E-Print Network [OSTI]

    Bliss, John Lawrence

    1981-01-01T23:59:59.000Z

    -counter in the field of an unshielded Cf source (Pi76) Texas A&M University Nuclear Science Center Neutron Radiography Facility . . . . . . . . . . . . . . . . . . 13 5 Neutron spectra of scattered neutrons within the NRF (Da81... NEUTRONS E Ir 0. 1 IJJ GAMMA RAYS 0, 01 0. 001 0. 5 2 3 4 5 DISTANCE F ROM T HE SOURCE (M) FIG. 3. The dose reading of TLD 700 and a ResI-counter in the field of an unshielded Cf source (F176). 232 12 Radiography Facility (NRF) at the Texas ASM...

  2. Dosimetry in Thermal Neutron Irradiation Facility at BMRR

    SciTech Connect (OSTI)

    Hu, J. P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Holden, N. E. [Brookhaven National Lab. (BNL), Upton, NY (United States); Reciniello, R. N.

    2014-05-23T23:59:59.000Z

    Radiation dosimetry for Neutron Capture Therapy (NCT) has been performed since 1959 at Thermal Neutron Irradiation Facility (TNIF) of the three-megawatt light-water cooled Brookhaven Medical Research Reactor (BMRR). In the early 1990s when more effective drug carriers were developed for NCT, in which the eye melanoma and brain tumors in rats were irradiated in situ, extensive clinical trials of small animals began using a focused thermal neutron beam. To improve the dosimetry at irradiation facility, a series of innovative designs and major modifications made to enhance the beam intensity and to ease the experimental sampling at BMRR were performed; including (1) in-core fuel addition to increase source strength and balance flux of neutrons towards two ports, (2) out of core moderator remodeling, done by replacing thicker D2O tanks at graphite-shutter interfacial areas, to expedite neutron thermalization, (3) beam shutter upgrade to reduce strayed neutrons and gamma dose, (4) beam collimator redesign to optimize the beam flux versus dose for animal treatment, (5) beam port shielding installation around the shutter opening area (lithium-6 enriched polyester-resin in boxes, attached with polyethylene plates) to reduce prompt gamma and fast neutron doses, (6) sample holder repositioning to optimize angle versus distance for a single organ or whole body irradiation, and (7) holder wall buildup with neutron reflector materials to increase dose and dose rate from scattered thermal neutrons. During the facility upgrade, reactor dosimetry was conducted using thermoluminescent dosimeters TLD for gamma dose estimate, using ion chambers to confirm fast neutron and gamma dose rate, and by the activation of gold-foils with and without cadmium-covers, for fast and thermal neutron flux determination. Based on the combined effect from the size and depth of tumor cells and the location and geometry of dosimeters, the measured flux from cadmium-difference method was 4 - 7 % lower than the statistical mean derived from the Monte-Carlo modeling (5% uncertainty). The dose rate measured by ion chambers was 6 - 10 % lower than the output tallies (7% uncertainty). The detailed dosimetry that was performed at the TNIF for the NCT will be described.

  3. A neutron source imaging detector for nuclear arms treaty verification

    SciTech Connect (OSTI)

    Sailor, W.C.; Byrd, R.C.; Gavron, A.; Hammock, R. (Los Alamos National Lab., Los Alamos, NM (US)); Yariv, Y. (Sorequ Nuclear Research Center, Yavne 70600 (IL))

    1991-11-01T23:59:59.000Z

    In this paper a detector design that is capable of finding the image of neutron sources within a nuclear missile is discussed. The method involves the double scatter of a neutron in an array of organic scintillator elements and the partial reconstruction of the incident neutron direction vector from the information the array provides. The Monte Carlo simulation results for a basic design and several modifications are presented. The results of an experimental demonstration of the technique using a crude prototype detector are given. Problems expected in a real application are discussed.

  4. SHARP Neutronics Expanded

    Broader source: Energy.gov [DOE]

    The SHARP neutronics module, PROTEUS, includes neutron and gamma transport solvers and cross-section processing tools as well as the capability for depletion and fuel cycle analysis.

  5. Differential cross section for neutron-proton bremsstrahlung

    E-Print Network [OSTI]

    Y. Safkan; T. Akdogan; W. A. Franklin; J. L. Matthews; W. M. Schmitt; V. V. Zelevinsky; P. A. M. Gram; T. N. Taddeucci; S. A. Wender; S. F. Pate

    2007-03-21T23:59:59.000Z

    The neutron-proton bremsstrahlung process $(np \\to np\\gamma)$ is known to be sensitive to meson exchange currents in the nucleon-nucleon interaction. The triply differential cross section for this reaction has been measured for the first time at the Los Alamos Neutron Science Center, using an intense, pulsed beam of up to 700 MeV neutrons to bombard a liquid hydrogen target. Scattered neutrons were observed at six angles between 12$^\\circ$ and 32$^\\circ$, and the recoil protons were observed in coincidence at 12$^\\circ$, 20$^\\circ$, and 28$^\\circ$ on the opposite side of the beam. Measurement of the neutron and proton energies at known angles allows full kinematic reconstruction of each event. The data are compared with predictions of two theoretical calculations, based on relativistic soft-photon and non-relativistic potential models.

  6. SCIENTIFIC CORRESPONDENCE Radiation doses

    E-Print Network [OSTI]

    Shlyakhter, Ilya

    -- ation doses and cancer rates to the workers m the first Soviet atom-bomb facility, near 2 Chelyabinsk

  7. Advanced neutron irradiation system using Texas A&M University Nuclear Science Center Reactor 

    E-Print Network [OSTI]

    Jang, Si Young

    2005-11-01T23:59:59.000Z

    plastic (A-150) and propane gas for total dose monitoring, and another with graphite and argon for photon dose monitoring. Using the pair of detectors, the neutron to gamma ratio can be inferred. With the 20 cm-thick FNIS, the absorbed dose rates...

  8. Data fusion in neutron and X-ray computed tomography

    SciTech Connect (OSTI)

    Schrapp, Michael J. [Siemens AG, Corporate Technology, Otto-Hahn-Ring 6, 81739 Munich (Germany); Physik Department E21, Technische Universität München, James-Franck-Strasse 1, 85747 Garching (Germany); Goldammer, Matthias [Siemens AG, Corporate Technology, Otto-Hahn-Ring 6, 81739 Munich (Germany); Schulz, Michael [Physik Department E21, Technische Universität München, James-Franck-Strasse 1, 85747 Garching (Germany); Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstrasse 1, 85747 Garching (Germany); Issani, Siraj; Bhamidipati, Suryanarayana [Siemens AG, Corporate Technology, Bangalore (India); Böni, Peter [Physik Department E21, Technische Universität München, James-Franck-Strasse 1, 85747 Garching (Germany)

    2014-10-28T23:59:59.000Z

    We present a fusion methodology between neutron and X-ray computed tomography (CT). On the one hand, the inspection by X-ray CT of a wide class of multimaterials in non-destructive testing applications suffers from limited information of object features. On the other hand, neutron imaging can provide complementary data in such a way that the combination of both data sets fully characterizes the object. In this contribution, a novel data fusion procedure, called Fusion Regularized Simultaneous Algebraic Reconstruction Technique, is developed where the X-ray reconstruction is modified to fulfill the available data from the imaging with neutrons. The experiments, which were obtained from an aluminum profile containing a steel screw, and attached carbon fiber plates demonstrate that the image quality in CT can be significantly improved when the proposed fusion method is used.

  9. Neutrostriction in Neutron stars

    E-Print Network [OSTI]

    V. K. Ignatovich

    2006-06-29T23:59:59.000Z

    It is demonstrated that not only gravity, but also neutrostriction forces due to optical potential created by coherent elastic neutron-neutron scattering can hold a neutron star together. The latter forces can be stronger than gravitational ones. The effect of these forces on mass, radius and structure of the neutron star is estimated.

  10. Reconstruction in Fourier space

    E-Print Network [OSTI]

    Burden, Angela; Howlett, Cullan

    2015-01-01T23:59:59.000Z

    We present a fast iterative FFT-based reconstruction algorithm that allows for non- parallel redshift-space distortions (RSD). We test our algorithm on both N-body dark matter simulations and mock distributions of galaxies designed to replicate galaxy survey conditions. We compare solenoidal and irrotational components of the redshift distortion and show that an approximation of this distortion leads to a better estimate of the real-space potential (and therefore faster convergence) than ignoring the RSD when estimating the displacement field. Our iterative reconstruction scheme converges in two iterations for the mock samples corresponding to BOSS CMASS DR11 when we start with an approximation of the RSD. The scheme takes six iterations when the initial estimate, measured from the redshift-space overdensity, has no RSD correction. Slower convergence would be expected for surveys covering a larger angle on the sky. We show that this FFT based method provides a better estimate of the real space displacement fi...

  11. Neutron reflecting supermirror structure

    DOE Patents [OSTI]

    Wood, James L. (Drayton Plains, MI)

    1992-01-01T23:59:59.000Z

    An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. One layer of each set of bilayers consist of titanium, and the second layer of each set of bilayers consist of an alloy of nickel with carbon interstitially present in the nickel alloy.

  12. Imaging with Scattered Neutrons

    E-Print Network [OSTI]

    H. Ballhausen; H. Abele; R. Gaehler; M. Trapp; A. Van Overberghe

    2006-10-30T23:59:59.000Z

    We describe a novel experimental technique for neutron imaging with scattered neutrons. These scattered neutrons are of interest for condensed matter physics, because they permit to reveal the local distribution of incoherent and coherent scattering within a sample. In contrast to standard attenuation based imaging, scattered neutron imaging distinguishes between the scattering cross section and the total attenuation cross section including absorption. First successful low-noise millimeter-resolution images by scattered neutron radiography and tomography are presented.

  13. Volumetric quantification of lung nodules in CT with iterative reconstruction (ASiR and MBIR)

    SciTech Connect (OSTI)

    Chen, Baiyu [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, North Carolina 27705 (United States)] [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, North Carolina 27705 (United States); Barnhart, Huiman [Department of Biostatistics and Bioinformatics, Duke University, Durham, North Carolina 27705 (United States)] [Department of Biostatistics and Bioinformatics, Duke University, Durham, North Carolina 27705 (United States); Richard, Samuel [Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, North Carolina 27705 and Department of Radiology, Duke University, Durham, North Carolina 27705 (United States)] [Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, North Carolina 27705 and Department of Radiology, Duke University, Durham, North Carolina 27705 (United States); Robins, Marthony [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States)] [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Colsher, James [Department of Radiology, Duke University, Durham, North Carolina 27705 (United States)] [Department of Radiology, Duke University, Durham, North Carolina 27705 (United States); Samei, Ehsan [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States) [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University, Durham, North Carolina 27705 (United States); Department of Physics, Department of Biomedical Engineering, and Department of Electronic and Computer Engineering, Duke University, Durham, North Carolina 27705 (United States)

    2013-11-15T23:59:59.000Z

    Purpose: Volume quantifications of lung nodules with multidetector computed tomography (CT) images provide useful information for monitoring nodule developments. The accuracy and precision of the volume quantification, however, can be impacted by imaging and reconstruction parameters. This study aimed to investigate the impact of iterative reconstruction algorithms on the accuracy and precision of volume quantification with dose and slice thickness as additional variables.Methods: Repeated CT images were acquired from an anthropomorphic chest phantom with synthetic nodules (9.5 and 4.8 mm) at six dose levels, and reconstructed with three reconstruction algorithms [filtered backprojection (FBP), adaptive statistical iterative reconstruction (ASiR), and model based iterative reconstruction (MBIR)] into three slice thicknesses. The nodule volumes were measured with two clinical software (A: Lung VCAR, B: iNtuition), and analyzed for accuracy and precision.Results: Precision was found to be generally comparable between FBP and iterative reconstruction with no statistically significant difference noted for different dose levels, slice thickness, and segmentation software. Accuracy was found to be more variable. For large nodules, the accuracy was significantly different between ASiR and FBP for all slice thicknesses with both software, and significantly different between MBIR and FBP for 0.625 mm slice thickness with Software A and for all slice thicknesses with Software B. For small nodules, the accuracy was more similar between FBP and iterative reconstruction, with the exception of ASIR vs FBP at 1.25 mm with Software A and MBIR vs FBP at 0.625 mm with Software A.Conclusions: The systematic difference between the accuracy of FBP and iterative reconstructions highlights the importance of extending current segmentation software to accommodate the image characteristics of iterative reconstructions. In addition, a calibration process may help reduce the dependency of accuracy on reconstruction algorithms, such that volumes quantified from scans of different reconstruction algorithms can be compared. The little difference found between the precision of FBP and iterative reconstructions could be a result of both iterative reconstruction's diminished noise reduction at the edge of the nodules as well as the loss of resolution at high noise levels with iterative reconstruction. The findings do not rule out potential advantage of IR that might be evident in a study that uses a larger number of nodules or repeated scans.

  14. Ground water and snow sensor based on directional detection of cosmogenic neutrons.

    SciTech Connect (OSTI)

    Cooper, Robert Lee; Marleau, Peter; Griffin, Patrick J.

    2011-06-01T23:59:59.000Z

    A fast neutron detector is being developed to measure the cosmic ray neutron flux in order to measure soil moisture. Soil that is saturated with water has an enhanced ability to moderate fast neutrons, removing them from the backscatter spectrum. The detector is a two-element, liquid scintillator detector. The choice of liquid scintillator allows rejection of gamma background contamination from the desired neutron signal. This enhances the ability to reconstruct the energy and direction of a coincident neutron event. The ability to image on an event-by-event basis allows the detector to selectively scan the neutron flux as a function of distance from the detector. Calibrations, simulations, and optimization have been completed to understand the detector response to neutron sources at variable distances and directions. This has been applied to laboratory background measurements in preparation for outdoor field tests.

  15. Shared Dosimetry Error in Epidemiological Dose-Response Analyses

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Stram, Daniel O.; Preston, Dale L.; Sokolnikov, Mikhail; Napier, Bruce; Kopecky, Kenneth J.; Boice, John; Beck, Harold; Till, John; Bouville, Andre; Zeeb, Hajo

    2015-03-23T23:59:59.000Z

    Radiation dose reconstruction systems for large-scale epidemiological studies are sophisticated both in providing estimates of dose and in representing dosimetry uncertainty. For example, a computer program was used by the Hanford Thyroid Disease Study to provide 100 realizations of possible dose to study participants. The variation in realizations reflected the range of possible dose for each cohort member consistent with the data on dose determinates in the cohort. Another example is the Mayak Worker Dosimetry System 2013 which estimates both external and internal exposures and provides multiple realizations of "possible" dose history to workers given dose determinants. This paper takesmore »up the problem of dealing with complex dosimetry systems that provide multiple realizations of dose in an epidemiologic analysis. In this paper we derive expected scores and the information matrix for a model used widely in radiation epidemiology, namely the linear excess relative risk (ERR) model that allows for a linear dose response (risk in relation to radiation) and distinguishes between modifiers of background rates and of the excess risk due to exposure. We show that treating the mean dose for each individual (calculated by averaging over the realizations) as if it was true dose (ignoring both shared and unshared dosimetry errors) gives asymptotically unbiased estimates (i.e. the score has expectation zero) and valid tests of the null hypothesis that the ERR slope ? is zero. Although the score is unbiased the information matrix (and hence the standard errors of the estimate of ?) is biased for ?6¼0 when ignoring errors in dose estimates, and we show how to adjust the information matrix to remove this bias, using the multiple realizations of dose. The use of these methods in the context of several studies including, the MayakWorker Cohort, and the U.S. Atomic Veterans Study, is discussed.« less

  16. Hiring Reconstruction Reports

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh School football High SchoolBundles toHiring Reconstruction Reports

  17. Neutron streak camera

    DOE Patents [OSTI]

    Wang, C.L.

    1981-05-14T23:59:59.000Z

    Apparatus for improved sensitivity and time resolution of a neutron measurement. The detector is provided with an electrode assembly having a neutron sensitive cathode which emits relatively low energy secondary electrons. The neutron sensitive cathode has a large surface area which provides increased sensitivity by intercepting a greater number of neutrons. The cathode is also curved to compensate for differences in transit time of the neutrons emanating from the point source. The slower speeds of the secondary electrons emitted from a certain portion of the cathode are matched to the transit times of the neutrons impinging thereupon.

  18. Layered semiconductor neutron detectors

    DOE Patents [OSTI]

    Mao, Samuel S; Perry, Dale L

    2013-12-10T23:59:59.000Z

    Room temperature operating solid state hand held neutron detectors integrate one or more relatively thin layers of a high neutron interaction cross-section element or materials with semiconductor detectors. The high neutron interaction cross-section element (e.g., Gd, B or Li) or materials comprising at least one high neutron interaction cross-section element can be in the form of unstructured layers or micro- or nano-structured arrays. Such architecture provides high efficiency neutron detector devices by capturing substantially more carriers produced from high energy .alpha.-particles or .gamma.-photons generated by neutron interaction.

  19. Neutron streak camera

    DOE Patents [OSTI]

    Wang, C.L.

    1983-09-13T23:59:59.000Z

    Disclosed is an apparatus for improved sensitivity and time resolution of a neutron measurement. The detector is provided with an electrode assembly having a neutron sensitive cathode which emits relatively low energy secondary electrons. The neutron sensitive cathode has a large surface area which provides increased sensitivity by intercepting a greater number of neutrons. The cathode is also curved to compensate for differences in transit time of the neutrons emanating from the point source. The slower speeds of the secondary electrons emitted from a certain portion of the cathode are matched to the transit times of the neutrons impinging thereupon. 4 figs.

  20. Spallation Neutron Source Radiation Shielding Issues

    SciTech Connect (OSTI)

    Azmy, Y.Y.; Barnes, J.M.; Drischler, J.D.; Johnston, J.O.; Lillie, R.A.; McNeilly, G.S.; Santoro, R.T.

    1999-11-14T23:59:59.000Z

    This paper summarizes results of Spallation Neutron Source calculations to estimate radiation hazards and shielding requirements for activated Mercury, target components, target cooling water, and {sup 7}Be plateout. Dose rates in the accelerator tunnel from activation of magnets and concrete were investigated. The impact of gaps and other streaming paths on the radiation environment inside the test cell during operation and after shutdown were also assessed.

  1. Microsoft Word - Y12NeutronDoseFinalDraft.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHighandSWPA / SPRA / USACE625Data Show Filtration8,2 14A: Distributions

  2. Ultrafast neutron detector

    DOE Patents [OSTI]

    Wang, C.L.

    1985-06-19T23:59:59.000Z

    A neutron detector of very high temporal resolution is described. It may be used to measure distributions of neutrons produced by fusion reactions that persist for times as short as about 50 picoseconds.

  3. Pulsed-neutron monochromator

    DOE Patents [OSTI]

    Mook, Jr., Herbert A. (Oak Ridge, TN)

    1985-01-01T23:59:59.000Z

    In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The wave are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

  4. Pulsed-neutron monochromator

    DOE Patents [OSTI]

    Mook, H.A. Jr.

    1984-01-01T23:59:59.000Z

    In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The waves are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

  5. Simulation of a D-T Neutron Source for Neutron Scattering Experiments

    E-Print Network [OSTI]

    Lou, T.P.; Ludewigt, B.A.; Vujic, J.L.; Leung, K.-N.

    2003-01-01T23:59:59.000Z

    T Neutron Source for Neutron Scattering Experiments T.P. Louor cold neutrons for neutron scattering experiments. Thisto simulate a neutron scattering setup and to estimate

  6. Bouncing Neutrons and the Neutron Centrifuge

    E-Print Network [OSTI]

    P. J. S. Watson

    2003-02-26T23:59:59.000Z

    The recent observation of the quantum state of the neutron bouncing freely under gravity allows some novel experiments. A method of purifying the ground state is given, and possible applications to the measurement of the electric dipole moment of the neutron and the short distance behaviour of gravity are discussed.

  7. Advanced neutron absorber materials

    DOE Patents [OSTI]

    Branagan, Daniel J. (Idaho Falls, ID); Smolik, Galen R. (Idaho Falls, ID)

    2000-01-01T23:59:59.000Z

    A neutron absorbing material and method utilizing rare earth elements such as gadolinium, europium and samarium to form metallic glasses and/or noble base nano/microcrystalline materials, the neutron absorbing material having a combination of superior neutron capture cross sections coupled with enhanced resistance to corrosion, oxidation and leaching.

  8. Arsenic activation neutron detector

    DOE Patents [OSTI]

    Jacobs, E.L.

    1980-01-28T23:59:59.000Z

    A detector of bursts of neutrons from a deuterium-deuteron reaction includes a quantity of arsenic adjacent a gamma detector such as a scintillator and photomultiplier tube. The arsenic is activated by the 2.5-MeV neutrons to release gamma radiation which is detected to give a quantitative representation of detected neutrons.

  9. Spacecraft Habitation Systems, Water Recovery and Waste Active Charged Particle and Neutron Radiation Measurement

    E-Print Network [OSTI]

    SBIR SBIR 62 63 I Spacecraft Habitation Systems, Water Recovery and Waste Management Active Charged indicate that secondary neutrons, with energies ranging between 0.5 to >150 MeV, make a significant discriminate between the fraction of dose, which results from secondary neutrons, and that which results from

  10. Metrological digital audio reconstruction

    DOE Patents [OSTI]

    Fadeyev; Vitaliy (Berkeley, CA), Haber; Carl (Berkeley, CA)

    2004-02-19T23:59:59.000Z

    Audio information stored in the undulations of grooves in a medium such as a phonograph record may be reconstructed, with little or no contact, by measuring the groove shape using precision metrology methods coupled with digital image processing and numerical analysis. The effects of damage, wear, and contamination may be compensated, in many cases, through image processing and analysis methods. The speed and data handling capacity of available computing hardware make this approach practical. Two examples used a general purpose optical metrology system to study a 50 year old 78 r.p.m. phonograph record and a commercial confocal scanning probe to study a 1920's celluloid Edison cylinder. Comparisons are presented with stylus playback of the samples and with a digitally re-mastered version of an original magnetic recording. There is also a more extensive implementation of this approach, with dedicated hardware and software.

  11. Reconstructing quantum theory

    E-Print Network [OSTI]

    Lucien Hardy

    2013-03-06T23:59:59.000Z

    We discuss how to reconstruct quantum theory from operational postulates. In particular, the following postulates are consistent only with for classical probability theory and quantum theory. Logical Sharpness: There is a one-to-one map between pure states and maximal effects such that we get unit probability. This maximal effect does not give probability equal to one for any other pure state. Information Locality: A maximal measurement is effected on a composite system if we perform maximal measurements on each of the components. Tomographic Locality: The state of a composite system can be determined from the statistics collected by making measurements on the components. Permutability: There exists a reversible transformation on any system effecting any given permutation of any given maximal set of distinguishable states for that system. Sturdiness: Filters are non-flattening. To single out quantum theory we need only add any requirement that is inconsistent with classical probability theory and consistent with quantum theory.

  12. Neutron scatter camera

    DOE Patents [OSTI]

    Mascarenhas, Nicholas; Marleau, Peter; Brennan, James S.; Krenz, Kevin D.

    2010-06-22T23:59:59.000Z

    An instrument that will directly image the fast fission neutrons from a special nuclear material source has been described. This instrument can improve the signal to background compared to non imaging neutron detection techniques by a factor given by ratio of the angular resolution window to 4.pi.. In addition to being a neutron imager, this instrument will also be an excellent neutron spectrometer, and will be able to differentiate between different types of neutron sources (e.g. fission, alpha-n, cosmic ray, and D-D or D-T fusion). Moreover, the instrument is able to pinpoint the source location.

  13. Semiconductor neutron detector

    DOE Patents [OSTI]

    Ianakiev, Kiril D. (Los Alamos, NM); Littlewood, Peter B. (Cambridge, GB); Blagoev, Krastan B. (Arlington, VA); Swinhoe, Martyn T. (Los Alamos, NM); Smith, James L. (Los Alamos, NM); Sullivan, Clair J. (Los Alamos, NM); Alexandrov, Boian S. (Los Alamos, NM); Lashley, Jason Charles (Santa Fe, NM)

    2011-03-08T23:59:59.000Z

    A neutron detector has a compound of lithium in a single crystal form as a neutron sensor element. The lithium compound, containing improved charge transport properties, is either lithium niobate or lithium tantalate. The sensor element is in direct contact with a monitor that detects an electric current. A signal proportional to the electric current is produced and is calibrated to indicate the neutrons sensed. The neutron detector is particularly useful for detecting neutrons in a radiation environment. Such radiation environment may, e.g. include gamma radiation and noise.

  14. Diamond detector for high rate monitors of fast neutrons beams

    SciTech Connect (OSTI)

    Giacomelli, L.; Rebai, M.; Cippo, E. Perelli; Tardocchi, M.; Fazzi, A.; Andreani, C.; Pietropaolo, A.; Frost, C. D.; Rhodes, N.; Schooneveld, E.; Gorini, G. [Dipartimento di Fisica, Universita degli Studi di Milano-Bicocca, and Istituto di Fisica del Plasma, Associazione EURATOM-ENEA-CNR, Milano (Italy); Energy Department, Politecnico di Milano, Milano (Italy); Dipartimento di Fisica, Centro NAST, Universita degli Studi di Roma Tor Vergata, Roma (Italy); STFC, ISIS facility, Rutherford Appleton Laboratory, Chilton Didcot Oxfordshire (United Kingdom); Dipartimento di Fisica, Universita degli Studi di Milano-Bicocca, and Istituto di Fisica del Plasma, Associazione EURATOM-ENEA-CNR, Milano (Italy)

    2012-06-19T23:59:59.000Z

    A fast neutron detection system suitable for high rate measurements is presented. The detector is based on a commercial high purity single crystal diamond (SDD) coupled to a fast digital data acquisition system. The detector was tested at the ISIS pulsed spallation neutron source. The SDD event signal was digitized at 1 GHz to reconstruct the deposited energy (pulse amplitude) and neutron arrival time; the event time of flight (ToF) was obtained relative to the recorded proton beam signal t{sub 0}. Fast acquisition is needed since the peak count rate is very high ({approx}800 kHz) due to the pulsed structure of the neutron beam. Measurements at ISIS indicate that three characteristics regions exist in the biparametric spectrum: i) background gamma events of low pulse amplitudes; ii) low pulse amplitude neutron events in the energy range E{sub dep}= 1.5-7 MeV ascribed to neutron elastic scattering on {sup 12}C; iii) large pulse amplitude neutron events with E{sub n} < 7 MeV ascribed to {sup 12}C(n,{alpha}){sup 9}Be and 12C(n,n')3{alpha}.

  15. The Neutron Lifetime

    E-Print Network [OSTI]

    F. E. Wietfeldt

    2014-11-13T23:59:59.000Z

    The decay of the free neutron into a proton, electron, and antineutrino is the prototype semileptonic weak decay and the simplest example of nuclear beta decay. The nucleon vector and axial vector weak coupling constants G_V and G_A determine the neutron lifetime as well as the strengths of weak interaction processes involving free neutrons and protons that are important in astrophysics, cosmology, solar physics and neutrino detection. In combination with a neutron decay angular correlation measurement, the neutron lifetime can be used to determine the first element of the CKM matrix Vud. Unfortunately the two main experimental methods for measuring the neutron lifetime currently disagree by almost 4 sigma. I will present a brief review of the status of the neutron lifetime and prospects for the future.

  16. Neutron tomography of axially symmetric objects using 14 MeV neutrons from a portable neutron generator

    SciTech Connect (OSTI)

    Andersson, P., E-mail: peter.andersson@physics.uu.se; Andersson-Sunden, E.; Sjöstrand, H.; Jacobsson-Svärd, S. [Department of Physics and Astronomy, Division of Applied Nuclear Physics, Uppsala University, Lägerhyddsgatan 1, 751 20 Uppsala (Sweden)

    2014-08-01T23:59:59.000Z

    In nuclear boiling water reactor cores, the distribution of water and steam (void) is essential for both safety and efficiency reasons. In order to enhance predictive capabilities, void distribution assessment is performed in two-phase test-loops under reactor-relevant conditions. This article proposes the novel technique of fast-neutron tomography using a portable deuterium-tritium neutron generator to determine the time-averaged void distribution in these loops. Fast neutrons have the advantage of high transmission through the metallic structures and pipes typically concealing a thermal-hydraulic test loop, while still being fairly sensitive to the water/void content. However, commercially available fast-neutron generators also have the disadvantage of a relatively low yield and fast-neutron detection also suffers from relatively low detection efficiency. Fortunately, some loops are axially symmetric, a property which can be exploited to reduce the amount of data needed for tomographic measurement, thus limiting the interrogation time needed. In this article, three axially symmetric test objects depicting a thermal-hydraulic test loop have been examined; steel pipes with outer diameter 24 mm, thickness 1.5 mm, and with three different distributions of the plastic material POM inside the pipes. Data recorded with the FANTOM fast-neutron tomography instrument have been used to perform tomographic reconstructions to assess their radial material distribution. Here, a dedicated tomographic algorithm that exploits the symmetry of these objects has been applied, which is described in the paper. Results are demonstrated in 20 rixel (radial pixel) reconstructions of the interior constitution and 2D visualization of the pipe interior is demonstrated. The local POM attenuation coefficients in the rixels were measured with errors (RMS) of 0.025, 0.020, and 0.022 cm{sup ?1}, solid POM attenuation coefficient. The accuracy and precision is high enough to provide a useful indication on the flow mode, and a visualization of the radial material distribution can be obtained. A benefit of this system is its potential to be mounted at any axial height of a two-phase test section without requirements for pre-fabricated entrances or windows. This could mean a significant increase in flexibility of the void distribution assessment capability at many existing two-phase test loops.

  17. Experimentally studied dynamic dose interplay does not meaningfully affect target dose in VMAT SBRT lung treatments

    SciTech Connect (OSTI)

    Stambaugh, Cassandra [Department of Physics, University of South Florida, Tampa, Florida 33612 (United States)] [Department of Physics, University of South Florida, Tampa, Florida 33612 (United States); Nelms, Benjamin E. [Canis Lupus LLC, Merrimac, Wisconsin 53561 (United States)] [Canis Lupus LLC, Merrimac, Wisconsin 53561 (United States); Dilling, Thomas; Stevens, Craig; Latifi, Kujtim; Zhang, Geoffrey; Moros, Eduardo; Feygelman, Vladimir [Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida 33612 (United States)] [Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida 33612 (United States)

    2013-09-15T23:59:59.000Z

    Purpose: The effects of respiratory motion on the tumor dose can be divided into the gradient and interplay effects. While the interplay effect is likely to average out over a large number of fractions, it may play a role in hypofractionated [stereotactic body radiation therapy (SBRT)] treatments. This subject has been extensively studied for intensity modulated radiation therapy but less so for volumetric modulated arc therapy (VMAT), particularly in application to hypofractionated regimens. Also, no experimental study has provided full four-dimensional (4D) dose reconstruction in this scenario. The authors demonstrate how a recently described motion perturbation method, with full 4D dose reconstruction, is applied to describe the gradient and interplay effects during VMAT lung SBRT treatments.Methods: VMAT dose delivered to a moving target in a patient can be reconstructed by applying perturbations to the treatment planning system-calculated static 3D dose. Ten SBRT patients treated with 6 MV VMAT beams in five fractions were selected. The target motion (motion kernel) was approximated by 3D rigid body translation, with the tumor centroids defined on the ten phases of the 4DCT. The motion was assumed to be periodic, with the period T being an average from the empirical 4DCT respiratory trace. The real observed tumor motion (total displacement ?8 mm) was evaluated first. Then, the motion range was artificially increased to 2 or 3 cm. Finally, T was increased to 60 s. While not realistic, making T comparable to the delivery time elucidates if the interplay effect can be observed. For a single fraction, the authors quantified the interplay effect as the maximum difference in the target dosimetric indices, most importantly the near-minimum dose (D{sub 99%}), between all possible starting phases. For the three- and five-fractions, statistical simulations were performed when substantial interplay was found.Results: For the motion amplitudes and periods obtained from the 4DCT, the interplay effect is negligible (<0.2%). It is also small (0.9% average, 2.2% maximum) when the target excursion increased to 2–3 cm. Only with large motion and increased period (60 s) was a significant interplay effect observed, with D{sub 99%} ranging from 16% low to 17% high. The interplay effect was statistically significantly lower for the three- and five-fraction statistical simulations. Overall, the gradient effect dominates the clinical situation.Conclusions: A novel method was used to reconstruct the volumetric dose to a moving tumor during lung SBRT VMAT deliveries. With the studied planning and treatment technique for realistic motion periods, regardless of the amplitude, the interplay has nearly no impact on the near-minimum dose. The interplay effect was observed, for study purposes only, with the period comparable to the VMAT delivery time.

  18. Estimation of Internal Radiation Dose from both Immediate Releases and Continued Exposures to Contaminated Materials

    SciTech Connect (OSTI)

    Napier, Bruce A.

    2012-03-26T23:59:59.000Z

    A brief description is provided of the basic concepts related to 'internal dose' and how it differs from doses that result from radioactive materials and direct radiation outside of the body. The principles of radiation dose reconstruction, as applied to both internal and external doses, is discussed based upon a recent publication prepared by the US National Council on Radiation Protection and Measurements. Finally, ideas are introduced related to residual radioactive contamination in the environment that has resulted from the releases from the damaged reactors and also to the management of wastes that may be generated in both regional cleanup and NPP decommissioning.

  19. Method to determine the position-dependant metal correction factor for dose-rate equivalent laser testing of semiconductor devices

    DOE Patents [OSTI]

    Horn, Kevin M.

    2013-07-09T23:59:59.000Z

    A method reconstructs the charge collection from regions beneath opaque metallization of a semiconductor device, as determined from focused laser charge collection response images, and thereby derives a dose-rate dependent correction factor for subsequent broad-area, dose-rate equivalent, laser measurements. The position- and dose-rate dependencies of the charge-collection magnitude of the device are determined empirically and can be combined with a digital reconstruction methodology to derive an accurate metal-correction factor that permits subsequent absolute dose-rate response measurements to be derived from laser measurements alone. Broad-area laser dose-rate testing can thereby be used to accurately determine the peak transient current, dose-rate response of semiconductor devices to penetrating electron, gamma- and x-ray irradiation.

  20. Dose factor entry and display tool for BNCT radiotherapy

    DOE Patents [OSTI]

    Wessol, Daniel E. (Bozeman, MT); Wheeler, Floyd J. (Idaho Falls, ID); Cook, Jeremy L. (Greeley, CO)

    1999-01-01T23:59:59.000Z

    A system for use in Boron Neutron Capture Therapy (BNCT) radiotherapy planning where a biological distribution is calculated using a combination of conversion factors and a previously calculated physical distribution. Conversion factors are presented in a graphical spreadsheet so that a planner can easily view and modify the conversion factors. For radiotherapy in multi-component modalities, such as Fast-Neutron and BNCT, it is necessary to combine each conversion factor component to form an effective dose which is used in radiotherapy planning and evaluation. The Dose Factor Entry and Display System is designed to facilitate planner entry of appropriate conversion factors in a straightforward manner for each component. The effective isodose is then immediately computed and displayed over the appropriate background (e.g. digitized image).

  1. PERTURBATION-BASED ERROR ANALYSIS OF ITERATIVE IMAGE RECONSTRUCTION ALGORITHM FOR X-RAY COMPUTED TOMOGRAPHY

    E-Print Network [OSTI]

    Fessler, Jeffrey A.

    -ray computed tomography. The effects of the quantization error in forward-projection, back computed tomography (CT) have been proposed to improve image quality and reduce dose [1]. These methodsPERTURBATION-BASED ERROR ANALYSIS OF ITERATIVE IMAGE RECONSTRUCTION ALGORITHM FOR X-RAY COMPUTED

  2. Reconstruction for proton computed tomography by tracing proton trajectories: A Monte Carlo study

    E-Print Network [OSTI]

    Reconstruction for proton computed tomography by tracing proton trajectories: A Monte Carlo study 11 January 2006; published 22 February 2006 Proton computed tomography pCT has been explored computed tomography pCT has several potential ad- vantages in medical applications. Its favorable dose

  3. NAC-1 cask dose rate calculations for LWR spent fuel

    SciTech Connect (OSTI)

    CARLSON, A.B.

    1999-02-24T23:59:59.000Z

    A Nuclear Assurance Corporation nuclear fuel transport cask, NAC-1, is being considered as a transport and storage option for spent nuclear fuel located in the B-Cell of the 324 Building. The loaded casks will be shipped to the 200 East Area Interim Storage Area for dry interim storage. Several calculations were performed to assess the photon and neutron dose rates. This report describes the analytical methods, models, and results of this investigation.

  4. Dose Reduction Techniques

    SciTech Connect (OSTI)

    WAGGONER, L.O.

    2000-05-16T23:59:59.000Z

    As radiation safety specialists, one of the things we are required to do is evaluate tools, equipment, materials and work practices and decide whether the use of these products or work practices will reduce radiation dose or risk to the environment. There is a tendency for many workers that work with radioactive material to accomplish radiological work the same way they have always done it rather than look for new technology or change their work practices. New technology is being developed all the time that can make radiological work easier and result in less radiation dose to the worker or reduce the possibility that contamination will be spread to the environment. As we discuss the various tools and techniques that reduce radiation dose, keep in mind that the radiological controls should be reasonable. We can not always get the dose to zero, so we must try to accomplish the work efficiently and cost-effectively. There are times we may have to accept there is only so much you can do. The goal is to do the smart things that protect the worker but do not hinder him while the task is being accomplished. In addition, we should not demand that large amounts of money be spent for equipment that has marginal value in order to save a few millirem. We have broken the handout into sections that should simplify the presentation. Time, distance, shielding, and source reduction are methods used to reduce dose and are covered in Part I on work execution. We then look at operational considerations, radiological design parameters, and discuss the characteristics of personnel who deal with ALARA. This handout should give you an overview of what it takes to have an effective dose reduction program.

  5. Neutron sources and applications

    SciTech Connect (OSTI)

    Price, D.L. [ed.] [Argonne National Lab., IL (United States); Rush, J.J. [ed.] [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

    1994-01-01T23:59:59.000Z

    Review of Neutron Sources and Applications was held at Oak Brook, Illinois, during September 8--10, 1992. This review involved some 70 national and international experts in different areas of neutron research, sources, and applications. Separate working groups were asked to (1) review the current status of advanced research reactors and spallation sources; and (2) provide an update on scientific, technological, and medical applications, including neutron scattering research in a number of disciplines, isotope production, materials irradiation, and other important uses of neutron sources such as materials analysis and fundamental neutron physics. This report summarizes the findings and conclusions of the different working groups involved in the review, and contains some of the best current expertise on neutron sources and applications.

  6. Spallation-neutron sources

    SciTech Connect (OSTI)

    Michaudon, A.

    1997-09-01T23:59:59.000Z

    Of particular interest for neutron-physics studies are spallation-neutron sources (SNSs) using intense proton beams with energies in the GeV range. Some SNSs already provide average fluxes of thermal and cold neutrons comparable with those of high-flux reactors. Most SNSs are pulsed with high peak fluxes that can be used with the powerful time-of-flight (TOF) method. Also, SNSs could be developed to much higher performance.

  7. Savannah River Site radioiodine atmospheric releases and offsite maximum doses

    SciTech Connect (OSTI)

    Marter, W.L.

    1990-11-01T23:59:59.000Z

    Radioisotopes of iodine have been released to the atmosphere from the Savannah River Site since 1955. The releases, mostly from the 200-F and 200-H Chemical Separations areas, consist of the isotopes, I-129 and 1-131. Small amounts of 1-131 and 1-133 have also been released from reactor facilities and the Savannah River Laboratory. This reference memorandum was issued to summarize our current knowledge of releases of radioiodines and resultant maximum offsite doses. This memorandum supplements the reference memorandum by providing more detailed supporting technical information. Doses reported in this memorandum from consumption of the milk containing the highest I-131 concentration following the 1961 1-131 release incident are about 1% higher than reported in the reference memorandum. This is the result of using unrounded 1-131 concentrations of I-131 in milk in this memo. It is emphasized here that this technical report does not constitute a dose reconstruction in the same sense as the dose reconstruction effort currently underway at Hanford. This report uses existing published data for radioiodine releases and existing transport and dosimetry models.

  8. Neutron Science Forum | ORNL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    environment for discussion, innovation, and dissemination of information within the neutron scattering community as well as engaging closely related disciplines through...

  9. Lujan Neutron Scattering Center

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the inadvertent spread of Technetium 99 by employees and contractors at the Lujan Neutron Scattering Center August 27, 2012-The Laboratory is investigating the inadvertent...

  10. HFIR History - ORNL Neutron Sciences

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    has grown to include materials irradiation, neutron activation, and, most recently, neutron scattering. In 2007, HFIR completed the most dramatic transformation in its...

  11. SU-D-BRE-07: Neutron Shielding Assessment for a Compact Proton Therapy Vault

    SciTech Connect (OSTI)

    Prusator, M; Ahmad, S; Chen, Y [University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States)

    2014-06-01T23:59:59.000Z

    Purpose: To perform a neutron shielding assessment of a commercially available compact proton therapy system. Methods: TOPAS (TOol for PArticle Simulation) beta release was used to model beam line components for Mevion S250 proton treatment system the design of which is that the cyclotron is present in the treatment room. Three neutron production sources were taken into account in the simulation. These are the cyclotron, the treatment nozzle and the patient itself, respectively. The cyclotron was modeled as a cylindrical iron target (r =5 cm, length = 8 cm). A water phantom (10 cm ×10 cm ×60 cm) was used to model the patient and various structures (scattering foils, range modulator wheel, applicator and compensator) defaulted in TOPAS were used to model the passive scattering treatment nozzle. Neutron fluences and energy spectra were counted in a spherical scoring geometry per incident proton in 18 angular bins (10 degree each). Fluence to dose conversion factors from ICRU publication 74 were used to acquire neutron ambient dose equivalent H*(10). A point source line of sight model was then used to calculate neutron dose at eight locations beyond shielding barriers. Results: The neutron ambient dose equivalent was calculated at the 8 points of interest around the proton treatment vault. The highest dose was found to be less than 0.781 mSv/year outside south barrier wall. However, the dose is less than 0.05 mSv/year at the control room area of the proton vault. Conclusion: All Points of interest were well under annual dose limits. This suggests that the shielding design of this compact proton therapy system is sufficient for radiation protection purpose. However, it is important to note that the workload and the occupancy factors are direct multipliers for dose calculations beyond the barrier and must be accurately estimated for validation of our results.

  12. Compact neutron generator

    DOE Patents [OSTI]

    Leung, Ka-Ngo; Lou, Tak Pui

    2005-03-22T23:59:59.000Z

    A compact neutron generator has at its outer circumference a toroidal shaped plasma chamber in which a tritium (or other) plasma is generated. A RF antenna is wrapped around the plasma chamber. A plurality of tritium ion beamlets are extracted through spaced extraction apertures of a plasma electrode on the inner surface of the toroidal plasma chamber and directed inwardly toward the center of neutron generator. The beamlets pass through spaced acceleration and focusing electrodes to a neutron generating target at the center of neutron generator. The target is typically made of titanium tubing. Water is flowed through the tubing for cooling. The beam can be pulsed rapidly to achieve ultrashort neutron bursts. The target may be moved rapidly up and down so that the average power deposited on the surface of the target may be kept at a reasonable level. The neutron generator can produce fast neutrons from a T-T reaction which can be used for luggage and cargo interrogation applications. A luggage or cargo inspection system has a pulsed T-T neutron generator or source at the center, surrounded by associated gamma detectors and other components for identifying explosives or other contraband.

  13. Neutron capture therapies

    DOE Patents [OSTI]

    Yanch, Jacquelyn C. (Cambridge, MA); Shefer, Ruth E. (Newton, MA); Klinkowstein, Robert E. (Winchester, MA)

    1999-01-01T23:59:59.000Z

    In one embodiment there is provided an application of the .sup.10 B(n,.alpha.).sup.7 Li nuclear reaction or other neutron capture reactions for the treatment of rheumatoid arthritis. This application, called Boron Neutron Capture Synovectomy (BNCS), requires substantially altered demands on neutron beam design than for instance treatment of deep seated tumors. Considerations for neutron beam design for the treatment of arthritic joints via BNCS are provided for, and comparisons with the design requirements for Boron Neutron Capture Therapy (BNCT) of tumors are made. In addition, exemplary moderator/reflector assemblies are provided which produce intense, high-quality neutron beams based on (p,n) accelerator-based reactions. In another embodiment there is provided the use of deuteron-based charged particle reactions to be used as sources for epithermal or thermal neutron beams for neutron capture therapies. Many d,n reactions (e.g. using deuterium, tritium or beryllium targets) are very prolific at relatively low deuteron energies.

  14. Calculation of radiation therapy dose using all particle Monte Carlo transport

    DOE Patents [OSTI]

    Chandler, William P. (Tracy, CA); Hartmann-Siantar, Christine L. (San Ramon, CA); Rathkopf, James A. (Livermore, CA)

    1999-01-01T23:59:59.000Z

    The actual radiation dose absorbed in the body is calculated using three-dimensional Monte Carlo transport. Neutrons, protons, deuterons, tritons, helium-3, alpha particles, photons, electrons, and positrons are transported in a completely coupled manner, using this Monte Carlo All-Particle Method (MCAPM). The major elements of the invention include: computer hardware, user description of the patient, description of the radiation source, physical databases, Monte Carlo transport, and output of dose distributions. This facilitated the estimation of dose distributions on a Cartesian grid for neutrons, photons, electrons, positrons, and heavy charged-particles incident on any biological target, with resolutions ranging from microns to centimeters. Calculations can be extended to estimate dose distributions on general-geometry (non-Cartesian) grids for biological and/or non-biological media.

  15. Calculation of radiation therapy dose using all particle Monte Carlo transport

    DOE Patents [OSTI]

    Chandler, W.P.; Hartmann-Siantar, C.L.; Rathkopf, J.A.

    1999-02-09T23:59:59.000Z

    The actual radiation dose absorbed in the body is calculated using three-dimensional Monte Carlo transport. Neutrons, protons, deuterons, tritons, helium-3, alpha particles, photons, electrons, and positrons are transported in a completely coupled manner, using this Monte Carlo All-Particle Method (MCAPM). The major elements of the invention include: computer hardware, user description of the patient, description of the radiation source, physical databases, Monte Carlo transport, and output of dose distributions. This facilitated the estimation of dose distributions on a Cartesian grid for neutrons, photons, electrons, positrons, and heavy charged-particles incident on any biological target, with resolutions ranging from microns to centimeters. Calculations can be extended to estimate dose distributions on general-geometry (non-Cartesian) grids for biological and/or non-biological media. 57 figs.

  16. Pocked surface neutron detector

    DOE Patents [OSTI]

    McGregor, Douglas (Whitmore Lake, MI); Klann, Raymond (Bolingbrook, IL)

    2003-04-08T23:59:59.000Z

    The detection efficiency, or sensitivity, of a neutron detector material such as of Si, SiC, amorphous Si, GaAs, or diamond is substantially increased by forming one or more cavities, or holes, in its surface. A neutron reactive material such as of elemental, or any compound of, .sup.10 B, .sup.6 Li, .sup.6 LiF, U, or Gd is deposited on the surface of the detector material so as to be disposed within the cavities therein. The portions of the neutron reactive material extending into the detector material substantially increase the probability of an energetic neutron reaction product in the form of a charged particle being directed into and detected by the neutron detector material.

  17. Pulsed neutron detector

    DOE Patents [OSTI]

    Robertson, deceased, J. Craig (late of Albuquerque, NM); Rowland, Mark S. (Livermore, CA)

    1989-03-21T23:59:59.000Z

    A pulsed neutron detector and system for detecting low intensity fast neutron pulses has a body of beryllium adjacent a body of hydrogenous material the latter of which acts as a beta particle detector, scintillator, and moderator. The fast neutrons (defined as having En>1.5 MeV) react in the beryllium and the hydrogenous material to produce larger numbers of slow neutrons than would be generated in the beryllium itself and which in the beryllium generate hellium-6 which decays and yields beta particles. The beta particles reach the hydrogenous material which scintillates to yield light of intensity related to the number of fast neutrons. A photomultiplier adjacent the hydrogenous material (scintillator) senses the light emission from the scintillator. Utilization means, such as a summing device, sums the pulses from the photo-multiplier for monitoring or other purposes.

  18. SINGLE CRYSTAL NEUTRON DIFFRACTION.

    SciTech Connect (OSTI)

    KOETZLE,T.F.

    2001-03-13T23:59:59.000Z

    Single-crystal neutron diffraction measures the elastic Bragg reflection intensities from crystals of a material, the structure of which is the subject of investigation. A single crystal is placed in a beam of neutrons produced at a nuclear reactor or at a proton accelerator-based spallation source. Single-crystal diffraction measurements are commonly made at thermal neutron beam energies, which correspond to neutron wavelengths in the neighborhood of 1 Angstrom. For high-resolution studies requiring shorter wavelengths (ca. 0.3-0.8 Angstroms), a pulsed spallation source or a high-temperature moderator (a ''hot source'') at a reactor may be used. When complex structures with large unit-cell repeats are under investigation, as is the case in structural biology, a cryogenic-temperature moderator (a ''cold source'') may be employed to obtain longer neutron wavelengths (ca. 4-10 Angstroms). A single-crystal neutron diffraction analysis will determine the crystal structure of the material, typically including its unit cell and space group, the positions of the atomic nuclei and their mean-square displacements, and relevant site occupancies. Because the neutron possesses a magnetic moment, the magnetic structure of the material can be determined as well, from the magnetic contribution to the Bragg intensities. This latter aspect falls beyond the scope of the present unit; for information on magnetic scattering of neutrons see Unit 14.3. Instruments for single-crystal diffraction (single-crystal diffractometers or SCDs) are generally available at the major neutron scattering center facilities. Beam time on many of these instruments is available through a proposal mechanism. A listing of neutron SCD instruments and their corresponding facility contacts is included in an appendix accompanying this unit.

  19. Investigation of statistical iterative reconstruction for dedicated breast CT

    SciTech Connect (OSTI)

    Makeev, Andrey; Glick, Stephen J. [UMass Medical School, 55 Lake Avenue North, Worcester, Massachusetts 01655 (United States)] [UMass Medical School, 55 Lake Avenue North, Worcester, Massachusetts 01655 (United States)

    2013-08-15T23:59:59.000Z

    Purpose: Dedicated breast CT has great potential for improving the detection and diagnosis of breast cancer. Statistical iterative reconstruction (SIR) in dedicated breast CT is a promising alternative to traditional filtered backprojection (FBP). One of the difficulties in using SIR is the presence of free parameters in the algorithm that control the appearance of the resulting image. These parameters require tuning in order to achieve high quality reconstructions. In this study, the authors investigated the penalized maximum likelihood (PML) method with two commonly used types of roughness penalty functions: hyperbolic potential and anisotropic total variation (TV) norm. Reconstructed images were compared with images obtained using standard FBP. Optimal parameters for PML with the hyperbolic prior are reported for the task of detecting microcalcifications embedded in breast tissue.Methods: Computer simulations were used to acquire projections in a half-cone beam geometry. The modeled setup describes a realistic breast CT benchtop system, with an x-ray spectra produced by a point source and an a-Si, CsI:Tl flat-panel detector. A voxelized anthropomorphic breast phantom with 280 ?m microcalcification spheres embedded in it was used to model attenuation properties of the uncompressed woman's breast in a pendant position. The reconstruction of 3D images was performed using the separable paraboloidal surrogates algorithm with ordered subsets. Task performance was assessed with the ideal observer detectability index to determine optimal PML parameters.Results: The authors' findings suggest that there is a preferred range of values of the roughness penalty weight and the edge preservation threshold in the penalized objective function with the hyperbolic potential, which resulted in low noise images with high contrast microcalcifications preserved. In terms of numerical observer detectability index, the PML method with optimal parameters yielded substantially improved performance (by a factor of greater than 10) compared to FBP. The hyperbolic prior was also observed to be superior to the TV norm. A few of the best-performing parameter pairs for the PML method also demonstrated superior performance for various radiation doses. In fact, using PML with certain parameter values results in better images, acquired using 2 mGy dose, than FBP-reconstructed images acquired using 6 mGy dose.Conclusions: A range of optimal free parameters for the PML algorithm with hyperbolic and TV norm-based potentials is presented for the microcalcification detection task, in dedicated breast CT. The reported values can be used as starting values of the free parameters, when SIR techniques are used for image reconstruction. Significant improvement in image quality can be achieved by using PML with optimal combination of parameters, as compared to FBP. Importantly, these results suggest improved detection of microcalcifications can be obtained by using PML with lower radiation dose to the patient, than using FBP with higher dose.

  20. Shape reconstruction from gradient data

    SciTech Connect (OSTI)

    Ettl, Svenja; Kaminski, Juergen; Knauer, Markus C.; Haeusler, Gerd

    2008-04-20T23:59:59.000Z

    We present a generalized method for reconstructing the shape of an object from measured gradient data. A certain class of optical sensors does not measure the shape of an object but rather its local slope. These sensors display several advantages, including high information efficiency, sensitivity, and robustness. For many applications, however, it is necessary to acquire the shape, which must be calculated from the slopes by numerical integration. Existing integration techniques show drawbacks that render them unusable in many cases. Our method is based on an approximation employing radial basis functions. It can be applied to irregularly sampled, noisy, and incomplete data, and it reconstructs surfaces both locally and globally with high accuracy.

  1. Semiconductor High-Level Dosimeters Used in the SLAC Mixed Gamma and Neutron Fields

    SciTech Connect (OSTI)

    Mao, Stan

    2003-09-03T23:59:59.000Z

    As part of an exploration of Semiconductor High-Level Dosimetry (SHLD) in the accelerator radiation fields, the response of SHLD system, composed of dual MOSFETs, wide-base PIN diode, and a microprocessor-controlled reader, was calibrated in photon (Co-60) and neutron (Bare-reactor) fields. The response curves for the MOSFET and the PIN diode were determined. The neutron sensitivity of the PIN diode is about a factor of 2200 times higher than its photon sensitivity. Therefore, the PIN diode can be used to measure the neutron dose and virtually ignore the photon dose contribution. The MOSFET can be used to estimate the photon dose after subtracting the ionizing effect of the neutrons. The SHLD was used in the SLAC mixed field to measure the photon and neutron doses around a copper beam dump. The photon measurements near the copper dump agreed reasonably with the FLUKA Monte Carlo calculations. The neutron measurements agreed with FLUKA calculations to within a factor of two.

  2. LMFBR fuel bundle distortion characterization using neutron tomography and potting

    SciTech Connect (OSTI)

    Betten, P.R.; Tow, D.M.

    1984-05-01T23:59:59.000Z

    A standard liquid metal fast breeder reactor (LMFBR) subassembly used in the Experimental Breeder Reactor II (EBRII) was investigated for fuel bundle distortion by both nondestructive and destructive methods, and the results from both methods were compared. The nondestructive method employed neutron tomography to reconstruct the locations of fuel elements through the use of a maximum entropy reconstruction algorithm known as MENT. The destructive method consisted of ''potting'' (a technique that embeds and permanently fixes the fuel elements in a solid matrix) the subassembly and then cutting and polishing the individual sections. The comparison indicated that the tomography reconstruction provided good results in describing the bundle geometry and spacer-wire locations, with the overall resolution being on the order of a spacer-wire diameter. A dimensional consistency check indicated that the element and spacer-wire dimensions were accurately reproduced in the reconstruction. It was found that in situ fuel elements deform axially in a helical spiral and that the reconstruction was able to identify this helical distortion to within approximately half of a spacerwire diameter.

  3. SU-E-T-75: Commissioning Optically Stimulated Luminescence Dosimeters for Fast Neutron Therapy

    SciTech Connect (OSTI)

    Young, L [UniversityWashington, Seattle, WA (United States); Yang, F; Sandison, G [University of Washington, Seattle, WA (United States); Woodworth, D [University of California, Santa Barbara, Santa Barbara, CA (United States); McCormick, Z [University of Nevada - Reno, Reno, Nevada (United States)

    2014-06-01T23:59:59.000Z

    Purpose: Fast neutrons therapy used at the University of Washington is clinically proven to be more effective than photon therapy in treating salivary gland and other cancers. A nanodot optically stimulated luminescence (OSL) system was chosen to be commissioned for patient in vivo dosimetry for neutron therapy. The OSL-based radiation detectors are not susceptible to radiation damage caused by neutrons compared to diodes or MOSFET systems. Methods: An In-Light microStar OSL system was commissioned for in vivo use by radiating Landauer nanodots with neutrons generated from 50.0 MeV protons accelerated onto a beryllium target. The OSLs were calibrated the depth of maximum dose in solid water localized to 150 cm SAD isocenter in a 10.3 cm square field. Linearity was tested over a typical clinical dose fractionation range i.e. 0 to 150 neutron-cGy. Correction factors for transient signal fading, trap depletion, gantry angle, field size, and wedge factor dependencies were also evaluated. The OSLs were photo-bleached between radiations using a tungsten-halogen lamp. Results: Landauer sensitivity factors published for each nanodot are valid for measuring photon and electron doses but do not apply for neutron irradiation. Individually calculated nanodot calibration factors exhibited a 2–5% improvement over calibration factors computed by the microStar InLight software. Transient fading effects had a significant impact on neutron dose reading accuracy compared to photon and electron in vivo dosimetry. Greater accuracy can be achieved by calibrating and reading each dosimeter within 1–2 hours after irradiation. No additional OSL correction factors were needed for field size, gantry angle, or wedge factors in solid water phantom measurements. Conclusion: OSL detectors are a useful for neutron beam in vivo dosimetry verification. Dosimetric accuracy comparable to conventional diode systems can be achieved. Accounting for transient fading effects during the neutron beam calibration is a critical component for achieving comparable accuracy.

  4. Muon Reconstruction and Identification in CMS

    SciTech Connect (OSTI)

    Everett, A. [Purdue University, West Lafayette, IN, 47906 (United States)

    2010-02-10T23:59:59.000Z

    We present the design strategies and status of the CMS muon reconstruction and identification identification software. Muon reconstruction and identification is accomplished through a variety of complementary algorithms. The CMS muon reconstruction software is based on a Kalman filter technique and reconstructs muons in the standalone muon system, using information from all three types of muon detectors, and links the resulting muon tracks with tracks reconstructed in the silicon tracker. In addition, a muon identification algorithm has been developed which tries to identify muons with high efficiency while maintaining a low probability of misidentification. The muon identification algorithm is complementary by design to the muon reconstruction algorithm that starts track reconstruction in the muon detectors. The identification algorithm accepts reconstructed tracks from the inner tracker and attempts to quantify the muon compatibility for each track using associated calorimeter and muon detector hit information. The performance status is based on detailed detector simulations as well as initial studies using cosmic muon data.

  5. Hypernuclear Physics for Neutron Stars

    E-Print Network [OSTI]

    Jurgen Schaffner-Bielich

    2008-01-24T23:59:59.000Z

    The role of hypernuclear physics for the physics of neutron stars is delineated. Hypernuclear potentials in dense matter control the hyperon composition of dense neutron star matter. The three-body interactions of nucleons and hyperons determine the stiffness of the neutron star equation of state and thereby the maximum neutron star mass. Two-body hyperon-nucleon and hyperon-hyperon interactions give rise to hyperon pairing which exponentially suppresses cooling of neutron stars via the direct hyperon URCA processes. Non-mesonic weak reactions with hyperons in dense neutron star matter govern the gravitational wave emissions due to the r-mode instability of rotating neutron stars.

  6. Switchable radioactive neutron source device

    DOE Patents [OSTI]

    Stanford, G.S.; Rhodes, E.A.; Devolpi, A.; Boyar, R.E.

    1987-11-06T23:59:59.000Z

    This invention is a switchable neutron generating apparatus comprised of a pair of plates, the first plate having an alpha emitter section on it and the second plate having a target material portion on it which generates neutrons when its nuclei absorb an alpha particle. In operation, the alpha portion of the first plate is aligned with the neutron portion of the second plate to produce neutrons and brought out of alignment to cease production of neutrons. 3 figs.

  7. Switchable radioactive neutron source device

    DOE Patents [OSTI]

    Boyar, Robert E. (La Grange, IL); DeVolpi, Alexander (Bolingbrook, IL); Stanford, George S. (Downers Grove, IL); Rhodes, Edgar A. (Woodridge, IL)

    1989-01-01T23:59:59.000Z

    This invention is a switchable neutron generating apparatus comprised of a pair of plates, the first plate having an alpha emitter section on it and the second plate having a target material portion on it which generates neutrons when its nuclei absorb an alpha particle. In operation, the alpha portion of the first plate is aligned with the neutron portion of the second plate to produce neutrons and brought out of alignment to cease production of neutrons.

  8. Iterative methods for dose reduction and image enhancement in tomography

    DOE Patents [OSTI]

    Miao, Jianwei; Fahimian, Benjamin Pooya

    2012-09-18T23:59:59.000Z

    A system and method for creating a three dimensional cross sectional image of an object by the reconstruction of its projections that have been iteratively refined through modification in object space and Fourier space is disclosed. The invention provides systems and methods for use with any tomographic imaging system that reconstructs an object from its projections. In one embodiment, the invention presents a method to eliminate interpolations present in conventional tomography. The method has been experimentally shown to provide higher resolution and improved image quality parameters over existing approaches. A primary benefit of the method is radiation dose reduction since the invention can produce an image of a desired quality with a fewer number projections than seen with conventional methods.

  9. Linear Signal Reconstruction from Jittered Sampling

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Linear Signal Reconstruction from Jittered Sampling Alessandro Nordio (1) , Carla jitter, which is based on the analysis of the mean square error (MSE) between the reconstructed sig- nal of digital signal reconstruction as a function of the clock jitter, number of quantization bits, signal

  10. Quantitative Monte Carlo-based holmium-166 SPECT reconstruction

    SciTech Connect (OSTI)

    Elschot, Mattijs; Smits, Maarten L. J.; Nijsen, Johannes F. W.; Lam, Marnix G. E. H.; Zonnenberg, Bernard A.; Bosch, Maurice A. A. J. van den; Jong, Hugo W. A. M. de [Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands); Viergever, Max A. [Image Sciences Institute, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands)] [Image Sciences Institute, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands)

    2013-11-15T23:59:59.000Z

    Purpose: Quantitative imaging of the radionuclide distribution is of increasing interest for microsphere radioembolization (RE) of liver malignancies, to aid treatment planning and dosimetry. For this purpose, holmium-166 ({sup 166}Ho) microspheres have been developed, which can be visualized with a gamma camera. The objective of this work is to develop and evaluate a new reconstruction method for quantitative {sup 166}Ho SPECT, including Monte Carlo-based modeling of photon contributions from the full energy spectrum.Methods: A fast Monte Carlo (MC) simulator was developed for simulation of {sup 166}Ho projection images and incorporated in a statistical reconstruction algorithm (SPECT-fMC). Photon scatter and attenuation for all photons sampled from the full {sup 166}Ho energy spectrum were modeled during reconstruction by Monte Carlo simulations. The energy- and distance-dependent collimator-detector response was modeled using precalculated convolution kernels. Phantom experiments were performed to quantitatively evaluate image contrast, image noise, count errors, and activity recovery coefficients (ARCs) of SPECT-fMC in comparison with those of an energy window-based method for correction of down-scattered high-energy photons (SPECT-DSW) and a previously presented hybrid method that combines MC simulation of photopeak scatter with energy window-based estimation of down-scattered high-energy contributions (SPECT-ppMC+DSW). Additionally, the impact of SPECT-fMC on whole-body recovered activities (A{sup est}) and estimated radiation absorbed doses was evaluated using clinical SPECT data of six {sup 166}Ho RE patients.Results: At the same noise level, SPECT-fMC images showed substantially higher contrast than SPECT-DSW and SPECT-ppMC+DSW in spheres ?17 mm in diameter. The count error was reduced from 29% (SPECT-DSW) and 25% (SPECT-ppMC+DSW) to 12% (SPECT-fMC). ARCs in five spherical volumes of 1.96–106.21 ml were improved from 32%–63% (SPECT-DSW) and 50%–80% (SPECT-ppMC+DSW) to 76%–103% (SPECT-fMC). Furthermore, SPECT-fMC recovered whole-body activities were most accurate (A{sup est}= 1.06 × A ? 5.90 MBq, R{sup 2}= 0.97) and SPECT-fMC tumor absorbed doses were significantly higher than with SPECT-DSW (p = 0.031) and SPECT-ppMC+DSW (p = 0.031).Conclusions: The quantitative accuracy of {sup 166}Ho SPECT is improved by Monte Carlo-based modeling of the image degrading factors. Consequently, the proposed reconstruction method enables accurate estimation of the radiation absorbed dose in clinical practice.

  11. Cylindrical neutron generator

    DOE Patents [OSTI]

    Leung, Ka-Ngo (Hercules, CA)

    2008-04-22T23:59:59.000Z

    A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.

  12. Cylindrical neutron generator

    DOE Patents [OSTI]

    Leung, Ka-Ngo (Hercules, CA)

    2009-12-29T23:59:59.000Z

    A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.

  13. Strangeness in Neutron Stars

    E-Print Network [OSTI]

    Fridolin Weber; Alexander Ho; Rodrigo P. Negreiros; Philip Rosenfield

    2006-04-20T23:59:59.000Z

    It is generally agreed on that the tremendous densities reached in the centers of neutron stars provide a high-pressure environment in which several intriguing particles processes may compete with each other. These range from the generation of hyperons to quark deconfinement to the formation of kaon condensates and H-matter. There are theoretical suggestions of even more exotic processes inside neutron stars, such as the formation of absolutely stable strange quark matter. In the latter event, neutron stars would be largely composed of strange quark matter possibly enveloped in a thin nuclear crust. This paper gives a brief overview of these striking physical possibilities with an emphasis on the role played by strangeness in neutron star matter, which constitutes compressed baryonic matter at ultra-high baryon number density but low temperature which is no accessible to relativistic heavy ion collision experiments.

  14. Shifting scintillator neutron detector

    DOE Patents [OSTI]

    Clonts, Lloyd G; Cooper, Ronald G; Crow, Jr., Morris Lowell; Hannah, Bruce W; Hodges, Jason P; Richards, John D; Riedel, Richard A

    2014-03-04T23:59:59.000Z

    Provided are sensors and methods for detecting thermal neutrons. Provided is an apparatus having a scintillator for absorbing a neutron, the scintillator having a back side for discharging a scintillation light of a first wavelength in response to the absorbed neutron, an array of wavelength-shifting fibers proximate to the back side of the scintillator for shifting the scintillation light of the first wavelength to light of a second wavelength, the wavelength-shifting fibers being disposed in a two-dimensional pattern and defining a plurality of scattering plane pixels where the wavelength-shifting fibers overlap, a plurality of photomultiplier tubes, in coded optical communication with the wavelength-shifting fibers, for converting the light of the second wavelength to an electronic signal, and a processor for processing the electronic signal to identify one of the plurality of scattering plane pixels as indicative of a position within the scintillator where the neutron was absorbed.

  15. Cylindrical neutron generator

    DOE Patents [OSTI]

    Leung, Ka-Ngo

    2005-06-14T23:59:59.000Z

    A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.

  16. Neutrons from multifragmentation reactions

    E-Print Network [OSTI]

    W. Trautmann; A. S. Botvina; J. Brzychczyk; N. Buyukcizmeci; I. N. Mishustin; P. Pawlowski; ALADIN2000 Collaboration

    2011-08-29T23:59:59.000Z

    The neutron emission in the fragmentation of stable and radioactive Sn and La projectiles of 600 MeV per nucleon has been studied with the Large Neutron Detector LAND coupled to the ALADIN forward spectrometer at SIS. A cluster-recognition algorithm is used to identify individual particles within the hit distributions registered with LAND. The obtained momentum distributions are extrapolated over the full phase space occupied by the neutrons from the projectile-spectator source. The mean multiplicities of spectator neutrons reach values of up to 12 and depend strongly on the isotopic composition of the projectile. An effective source temperature of T approx. 3 - 4 MeV is deduced from the transverse momentum distributions. For the interpretation of the data, calculations with the Statistical Multifragmentation Model for a properly chosen ensemble of excited sources were performed. The possible modification of the liquid-drop parameters of the fragment description in the hot environment is studied, and a significant reduction of the symmetry-term coefficient is found necessary to simultaneously reproduce the neutron multiplicities and the mean neutron-to-proton ratios /Z of Z <= 10 fragments. Because of the similarity of the freeze-out conditions with those encountered in supernova scenarios, this is of astrophysical interest.

  17. Effect of electronic reconstruction on cuprate-manganite spin switches.

    SciTech Connect (OSTI)

    Liu, Y.; Visani, C.; Nemes, N. M.; Fitzsimmons, M. R.; Zhu, L. Y.; Tornos, J.; Zhernenkov, M.; Hoffmann, A.; Leon, C.; Santamaria, J.; te Velthuis, S. G. E. (Materials Science Division); (Universidad Complutense de Madrid); (LANL)

    2012-01-01T23:59:59.000Z

    We examine the anomalous inverse spin switch behavior in La{sub 0.7}Ca{sub 0.3}MnO{sub 3}(LCMO)/YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO)/LCMO trilayers by combined transport studies and polarized neutron reflectometry. Measuring magnetization profiles and magnetoresistance in an in-plane rotating magnetic field, we prove that, contrary to many accepted theoretical scenarios, the relative orientation between the two LCMO's magnetizations is not sufficient to determine the magnetoresistance. Rather the field dependence of magnetoresistance is explained by the interplay between the applied magnetic field and the (exponential tail of the) induced exchange field in YBCO, the latter originating from the electronic reconstruction at the LCMO/YBCO interfaces.

  18. GROUND-WATER CONTRIBUTION TO DOSE FROM PAST HANFORD OPERATIONS

    SciTech Connect (OSTI)

    Freshley, M. D.; Thorne, P. D.

    1992-01-01T23:59:59.000Z

    The Hanford Environmental Dose Reconstruction (HEOR) Project is being conducted to estimate radiation doses that populations and individuals could have received from Hanford Site operations from 1944 to the present. Four possible pathways by which radionuclides originating in ground water on the Hanford Site could have reached the public have been identified: 1) through contaminated ground water migrating to the Columbia River; 2) through wells on or adjacent to the Hanford Site; 3) through wells that draw some or all of their water from the Columbia River (riparian wells); and 4) through atmospheric deposition resulting in the contamination of a small watershed that, in turn, results in contamination of a shallow well or spring. These four pathways make up the "ground-water pathway ," which is the subject of this study. The objective of the study was to assess the extent to which the groundwater pathway contributed to radiation doses that populations or individuals may have received from past operations at Hanford. The assessment presented in this report was performed by 1) reviewing the extensive ?literature on ground water and ground-water monitoring at Hanford and 2) performing simple calculations to estimate radionuclide concentrations in ground water and the Columbia River resulting from ground-water discharge. Radiation doses that would result from exposure to this ground water and surface water were calculated. The study conclusion is that the ground-water pathways did not contribute significantly to dose. Compared with background radiation in the TriCities {300 mrem/yr), estimated doses are small: 0.02 mrem/yr effective dose equivalent from discharge of contaminated ground water to the Columbia River; 1 mrem/yr effective dose equivalent from Hanford Site wells; 11 mrem/yr effective dose equivalent from riparian wells; and 1 mrem/yr effective dose equivalent from the watershed. Because the estimated doses are so small, the recommendation is that further work on the ground-water pathway be limited to tracking ongoing ground-water studies at the Hanford Site.

  19. Standardized radiological dose evaluations

    SciTech Connect (OSTI)

    Peterson, V.L.; Stahlnecker, E.

    1996-05-01T23:59:59.000Z

    Following the end of the Cold War, the mission of Rocky Flats Environmental Technology Site changed from production of nuclear weapons to cleanup. Authorization baseis documents for the facilities, primarily the Final Safety Analysis Reports, are being replaced with new ones in which accident scenarios are sorted into coarse bins of consequence and frequency, similar to the approach of DOE-STD-3011-94. Because this binning does not require high precision, a standardized approach for radiological dose evaluations is taken for all the facilities at the site. This is done through a standard calculation ``template`` for use by all safety analysts preparing the new documents. This report describes this template and its use.

  20. Neutron-deuteron breakup reaction as a tool for studying neutron-neutron interactions

    SciTech Connect (OSTI)

    Konobeevski, E. S., E-mail: konobeev@inr.ru; Zuyev, S. V.; Mordovskoy, M. V.; Potashev, S. I.; Sharapov, I. M. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)] [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)

    2013-11-15T23:59:59.000Z

    An analysis of the most recent data on the reaction nd {yields} pnn revealed a serious discrepancy between theoretical predictions and cross sections measured for this reaction in various configurations where the role of neutron-neutron interactions is important. In view of this, it seems necessary both to develop theoretical approaches and to obtain new experimental data. For this purpose, a setup for studying the neutron-deuteron breakup reaction was created at the Institute for Nuclear Research on the basis of the neutron beam in the RADEX channel and deuterium targets. This facility makes it possible to perform experiments over a broad region of primary-neutron energies (10-60 MeV) and in various (final-state interaction, quasifree scattering, and spatial-star) configurations. Preliminary results of the respective experiment were obtained for configurations of final-state neutron-neutron interaction and quasifree neutron-neutron scattering.

  1. ORISE: Dose modeling and assessments

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    or state regulatory compliance requirements are being met during the decontamination and decommissioning of nuclear facilities. Dose modeling is an important step in the...

  2. Strangeness in Neutron Stars

    E-Print Network [OSTI]

    Fridolin Weber

    2000-08-23T23:59:59.000Z

    It is generally agreed on that the tremendous densities reached in the centers of neutron stars provide a high-pressure environment in which numerous novel particles processes are likely to compete with each other. These processes range from the generation of hyperons to quark deconfinement to the formation of kaon condensates and H-matter. There are theoretical suggestions of even more exotic processes inside neutron stars, such as the formation of absolutely stable strange quark matter, a configuration of matter even more stable than the most stable atomic nucleus, iron. In the latter event, neutron stars would be largely composed of pure quark matter, eventually enveloped in a thin nuclear crust. No matter which physical processes are actually realized inside neutron stars, each one leads to fingerprints, some more pronounced than others though, in the observable stellar quantities. This feature combined with the unprecedented progress in observational astronomy, which allows us to see vistas with remarkable clarity that previously were only imagined, renders neutron stars to nearly ideal probes for a wide range of physical studies, including the role of strangeness in dense matter.

  3. Portable Neutron Sensors for Emergency Response Operations

    SciTech Connect (OSTI)

    Mukhopadhyay, S., Maurer, R., Detweiler, R.

    2012-06-22T23:59:59.000Z

    This slide-show presents neutron measurement work, including design, use and performance of different neutron detection systems.

  4. Neutron beam characterization at the Neutron Radiography Reactor (NRAD)

    SciTech Connect (OSTI)

    Imel, G.R.; Urbatsch, T.; Pruett, D.P.; Ross, J.R.

    1990-01-01T23:59:59.000Z

    The Neutron Radiography Reactor (NRAD) is a 250-kW TRIGA Reactor operated by Argonne National Laboratory and is located near Idaho Falls, Idaho. The reactor and its facilities regarding radiography are detailed in another paper at this conference; this paper summarizes neutron flux measurements and calculations that have been performed to better understand and potentially improve the neutronics characteristics of the reactor.

  5. Spherical neutron generator

    DOE Patents [OSTI]

    Leung, Ka-Ngo

    2006-11-21T23:59:59.000Z

    A spherical neutron generator is formed with a small spherical target and a spherical shell RF-driven plasma ion source surrounding the target. A deuterium (or deuterium and tritium) ion plasma is produced by RF excitation in the plasma ion source using an RF antenna. The plasma generation region is a spherical shell between an outer chamber and an inner extraction electrode. A spherical neutron generating target is at the center of the chamber and is biased negatively with respect to the extraction electrode which contains many holes. Ions passing through the holes in the extraction electrode are focused onto the target which produces neutrons by D-D or D-T reactions.

  6. Ultrafast neutron detector

    DOE Patents [OSTI]

    Wang, Ching L. (Livermore, CA)

    1987-01-01T23:59:59.000Z

    The invention comprises a neutron detector (50) of very high temporal resolution that is particularly well suited for measuring the fusion reaction neutrons produced by laser-driven inertial confinement fusion targets. The detector comprises a biased two-conductor traveling-wave transmission line (54, 56, 58, 68) having a uranium cathode (60) and a phosphor anode (62) as respective parts of the two conductors. A charge line and Auston switch assembly (70, 72, 74) launch an electric field pulse along the transmission line. Neutrons striking the uranium cathode at a location where the field pulse is passing, are enabled to strike the phosphor anode and produce light that is recorded on photographic film (64). The transmission line may be variously configured to achieve specific experimental goals.

  7. Neutron Scattering Tutorials | Neutron Science | ORNL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy:Nanowire Solar541,9337, 2011 at3,Neutron Scattering Tutorials SHARE

  8. Corrosion resistant neutron absorbing coatings

    DOE Patents [OSTI]

    Choi, Jor-Shan; Farmer, Joseph C; Lee, Chuck K; Walker, Jeffrey; Russell, Paige; Kirkwood, Jon; Yang, Nancy; Champagne, Victor

    2013-11-12T23:59:59.000Z

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  9. Corrosion resistant neutron absorbing coatings

    DOE Patents [OSTI]

    Choi, Jor-Shan (El Cerrito, CA); Farmer, Joseph C. (Tracy, CA); Lee, Chuck K. (Hayward, CA); Walker, Jeffrey (Gaithersburg, MD); Russell, Paige (Las Vegas, NV); Kirkwood, Jon (Saint Leonard, MD); Yang, Nancy (Lafayette, CA); Champagne, Victor (Oxford, PA)

    2012-05-29T23:59:59.000Z

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  10. Neutron Science and Technology

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy:Nanowire Solar541,9337, 2011 at3,Neutron Scattering3 Neutron Science

  11. Neutron dosimetry in organs of an adult human phantom using linacs with multileaf collimator in radiotherapy treatments

    SciTech Connect (OSTI)

    Martinez-Ovalle, S. A.; Barquero, R.; Gomez-Ros, J. M.; Lallena, A. M. [Grupo de Fisica Nuclear Aplicada y Simulacion, Universidad Pedagogica y Tecnologica de Colombia, Tunja 15001000 (Colombia); Servicio de Proteccion Radiologica, Hospital Clinico Universitario, E-47012 Valladolid (Spain) and Departamento de Radiologia, Universidad de Valladolid, Valladolid E-47071 (Spain); CIEMAT, Avda. Complutense 40, Madrid, E-28040 (Spain); Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, Granada E-18071 (Spain)

    2012-05-15T23:59:59.000Z

    Purpose: To calculate absorbed doses due to neutrons in 87 organs/tissues for anthropomorphic phantoms, irradiated in position supine (head first into the gantry) with orientations anteroposterior (AP) and right-left (RLAT) with a 18 MV accelerator. Conversion factors from monitor units to {mu}Gy per neutron in organs, equivalent doses in organs/tissues, and effective doses, which permit to quantify stochastic risks, are estimated. Methods: MAX06 and FAX06 phantoms were modeled with MCNPX and irradiated with a 18 MV Varian Clinac 2100C/D accelerator whose geometry included a multileaf collimator. Two actual fields of a pelvic treatment were simulated using electron-photon-neutron coupled transport. Absorbed doses due to neutrons were estimated from kerma. Equivalent doses were estimated using the radiation weighting factor corresponding to an average incident neutron energy 0.47 MeV. Statistical uncertainties associated to absorbed doses, as calculated by MCNPX, were also obtained. Results: Largest doses were absorbed in shallowest (with respect to the neutron pathway) organs. In {mu}GyMU{sup -1}, values of 2.66 (for penis) and 2.33 (for testes) were found in MAX06, and 1.68 (for breasts), 1.05 (for lenses of eyes), and 0.94 (for sublingual salivary glands) in FAX06, in AP orientation. In RLAT, the largest doses were found for bone tissues (leg) just at the entrance of the beam in the body (right side in our case). Values, in {mu}GyMU{sup -1}, of 1.09 in upper leg bone right spongiosa, for MAX06, and 0.63 in mandible spongiosa, for FAX06, were found. Except for gonads, liver, and stomach wall, equivalent doses found for FAX06 were, in both orientations, higher than for MAX06. Equivalent doses in AP are higher than in RLAT for all organs/tissues other than brain and liver. Effective doses of 12.6 and 4.1 {mu}SvMU{sup -1} were found for AP and RLAT, respectively. The organs/tissues with larger relative contributions to the effective dose were testes and breasts, in AP, and breasts and red marrow, in RLAT. Equivalent and effective doses obtained for MAX06/FAX06 were smaller (between 2 and 20 times) than those quoted for the mathematical phantoms ADAM/EVA in ICRP-74. Conclusions: The new calculations of conversion coefficients for neutron irradiation in AP and RLAT irradiation geometries show a reduction in the values of effective dose by factors 7 (AP) and 6 (RLAT) with respect to the old data obtained with mathematical phantoms. The existence of tissues or anatomical regions with maximum absorbed doses, such as penis, lens of eyes, fascia (part of connective tissue), etc., organs/tissues that classic mathematical phantoms did not include because they were not considered for the study of stochastic effects, has been revealed. Absorbed doses due to photons, obtained following the same simulation methodology, are larger than those due to neutrons, reaching values 100 times larger as the primary beam is approached. However, for organs far from the treated volume, absorbed photon doses can be up to three times smaller than neutron ones. Calculations using voxel phantoms permitted to know the organ dose conversion coefficients per MU due to secondary neutrons in the complete anatomy of a patient.

  12. Method for position emission mammography image reconstruction

    DOE Patents [OSTI]

    Smith, Mark Frederick

    2004-10-12T23:59:59.000Z

    An image reconstruction method comprising accepting coincidence datat from either a data file or in real time from a pair of detector heads, culling event data that is outside a desired energy range, optionally saving the desired data for each detector position or for each pair of detector pixels on the two detector heads, and then reconstructing the image either by backprojection image reconstruction or by iterative image reconstruction. In the backprojection image reconstruction mode, rays are traced between centers of lines of response (LOR's), counts are then either allocated by nearest pixel interpolation or allocated by an overlap method and then corrected for geometric effects and attenuation and the data file updated. If the iterative image reconstruction option is selected, one implementation is to compute a grid Siddon retracing, and to perform maximum likelihood expectation maiximization (MLEM) computed by either: a) tracing parallel rays between subpixels on opposite detector heads; or b) tracing rays between randomized endpoint locations on opposite detector heads.

  13. NEUTRON AND NON-NEUTRON NUCLEAR DATA FOR RADIATION DOSIMETRY

    SciTech Connect (OSTI)

    HOLDEN,N.E.

    1999-09-10T23:59:59.000Z

    NEUTRON NUCLEAR DATA THAT IS USED IN REACTOR DOSIMETRY INCLUDE THERMAL NEUTRON CROSS SECTIONS AND NEUTRON RESONANCE INTEGRALS, FISSION SPECTRUM AVERAGED CROSS SECTIONS FOR REACTIONS ON A TARGET NUCLEUS. NON-NEUTRON NUCLEAR DATA USED IN REACTOR DOSIMETRY INCLUDE ISOTOPIC COMPOSITIONS OF TARGET NUCLIDES AND RADIOACTIVE HALF-LIVES, GAMMA-RAY ENERGIES AND INTENSITIES OF REACTION PRODUCT NUCLIDES. ALL OF THESE DATA ARE PERIODICALLY EVALUATED AND RECOMMENDED VALUES ARE PROVIDED IN THE HANDBOOK OF CHEMISTRY AND PHYSICS. THE LATEST RECOMMENDED VALUES ARE DISCUSSED AND THEY ARE CONTRASTED WITH SOME EARLIER NUCLEAR DATA, WHICH WAS PROVIDED WITH NEUTRON DETECTOR FOILS.

  14. Statistical model based iterative reconstruction (MBIR) in clinical CT systems: Experimental assessment of noise performance

    SciTech Connect (OSTI)

    Li, Ke; Tang, Jie [Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705 (United States)] [Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705 (United States); Chen, Guang-Hong, E-mail: gchen7@wisc.edu [Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705 and Department of Radiology, University of Wisconsin-Madison, 600 Highland Avenue, Madison, Wisconsin 53792 (United States)] [Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705 and Department of Radiology, University of Wisconsin-Madison, 600 Highland Avenue, Madison, Wisconsin 53792 (United States)

    2014-04-15T23:59:59.000Z

    Purpose: To reduce radiation dose in CT imaging, the statistical model based iterative reconstruction (MBIR) method has been introduced for clinical use. Based on the principle of MBIR and its nonlinear nature, the noise performance of MBIR is expected to be different from that of the well-understood filtered backprojection (FBP) reconstruction method. The purpose of this work is to experimentally assess the unique noise characteristics of MBIR using a state-of-the-art clinical CT system. Methods: Three physical phantoms, including a water cylinder and two pediatric head phantoms, were scanned in axial scanning mode using a 64-slice CT scanner (Discovery CT750 HD, GE Healthcare, Waukesha, WI) at seven different mAs levels (5, 12.5, 25, 50, 100, 200, 300). At each mAs level, each phantom was repeatedly scanned 50 times to generate an image ensemble for noise analysis. Both the FBP method with a standard kernel and the MBIR method (Veo{sup ®}, GE Healthcare, Waukesha, WI) were used for CT image reconstruction. Three-dimensional (3D) noise power spectrum (NPS), two-dimensional (2D) NPS, and zero-dimensional NPS (noise variance) were assessed both globally and locally. Noise magnitude, noise spatial correlation, noise spatial uniformity and their dose dependence were examined for the two reconstruction methods. Results: (1) At each dose level and at each frequency, the magnitude of the NPS of MBIR was smaller than that of FBP. (2) While the shape of the NPS of FBP was dose-independent, the shape of the NPS of MBIR was strongly dose-dependent; lower dose lead to a “redder” NPS with a lower mean frequency value. (3) The noise standard deviation (?) of MBIR and dose were found to be related through a power law of ????(dose){sup ??} with the component ? ? 0.25, which violated the classical ????(dose){sup ?0.5} power law in FBP. (4) With MBIR, noise reduction was most prominent for thin image slices. (5) MBIR lead to better noise spatial uniformity when compared with FBP. (6) A composite image generated from two MBIR images acquired at two different dose levels (D1 and D2) demonstrated lower noise than that of an image acquired at a dose level of D1+D2. Conclusions: The noise characteristics of the MBIR method are significantly different from those of the FBP method. The well known tradeoff relationship between CT image noise and radiation dose has been modified by MBIR to establish a more gradual dependence of noise on dose. Additionally, some other CT noise properties that had been well understood based on the linear system theory have also been altered by MBIR. Clinical CT scan protocols that had been optimized based on the classical CT noise properties need to be carefully re-evaluated for systems equipped with MBIR in order to maximize the method's potential clinical benefits in dose reduction and/or in CT image quality improvement.

  15. CT reconstruction techniques for improved accuracy of lung CT airway measurement

    SciTech Connect (OSTI)

    Rodriguez, A. [Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705 (United States); Ranallo, F. N. [Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705 and Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792 (United States); Judy, P. F. [Brigham and Women’s Hospital, Boston, Massachusetts 02115 (United States); Gierada, D. S. [Department of Radiology, Washington University, St. Louis, Missouri 63110 (United States); Fain, S. B., E-mail: sfain@wisc.edu [Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705 (United States); Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792 (United States); Department of Biomedical Engineering,University of Wisconsin School of Engineering, Madison, Wisconsin 53706 (United States)

    2014-11-01T23:59:59.000Z

    Purpose: To determine the impact of constrained reconstruction techniques on quantitative CT (qCT) of the lung parenchyma and airways for low x-ray radiation dose. Methods: Measurement of small airways with qCT remains a challenge, especially for low x-ray dose protocols. Images of the COPDGene quality assurance phantom (CTP698, The Phantom Laboratory, Salem, NY) were obtained using a GE discovery CT750 HD scanner for helical scans at x-ray radiation dose-equivalents ranging from 1 to 4.12 mSv (12–100 mA s current–time product). Other parameters were 40 mm collimation, 0.984 pitch, 0.5 s rotation, and 0.625 mm thickness. The phantom was sandwiched between 7.5 cm thick water attenuating phantoms for a total length of 20 cm to better simulate the scatter conditions of patient scans. Image data sets were reconstructed using STANDARD (STD), DETAIL, BONE, and EDGE algorithms for filtered back projection (FBP), 100% adaptive statistical iterative reconstruction (ASIR), and Veo reconstructions. Reduced (half) display field of view (DFOV) was used to increase sampling across airway phantom structures. Inner diameter (ID), wall area percent (WA%), and wall thickness (WT) measurements of eight airway mimicking tubes in the phantom, including a 2.5 mm ID (42.6 WA%, 0.4 mm WT), 3 mm ID (49.0 WA%, 0.6 mm WT), and 6 mm ID (49.0 WA%, 1.2 mm WT) were performed with Airway Inspector (Surgical Planning Laboratory, Brigham and Women’s Hospital, Boston, MA) using the phase congruency edge detection method. The average of individual measures at five central slices of the phantom was taken to reduce measurement error. Results: WA% measures were greatly overestimated while IDs were underestimated for the smaller airways, especially for reconstructions at full DFOV (36 cm) using the STD kernel, due to poor sampling and spatial resolution (0.7 mm pixel size). Despite low radiation dose, the ID of the 6 mm ID airway was consistently measured accurately for all methods other than STD FBP. Veo reconstructions showed slight improvement over STD FBP reconstructions (4%–9% increase in accuracy). The most improved ID and WA% measures were for the smaller airways, especially for low dose scans reconstructed at half DFOV (18 cm) with the EDGE algorithm in combination with 100% ASIR to mitigate noise. Using the BONE + ASIR at half BONE technique, measures improved by a factor of 2 over STD FBP even at a quarter of the x-ray dose. Conclusions: The flexibility of ASIR in combination with higher frequency algorithms, such as BONE, provided the greatest accuracy for conventional and low x-ray dose relative to FBP. Veo provided more modest improvement in qCT measures, likely due to its compatibility only with the smoother STD kernel.

  16. The tokamak as a neutron source

    SciTech Connect (OSTI)

    Hendel, H.W.; Jassby, D.L.

    1989-11-01T23:59:59.000Z

    This paper describes the tokamak in its role as a neutron source, with emphasis on experimental results for D-D neutron production. The sections summarize tokamak operation, sources of fusion and non-fusion neutrons, principal neutron detection methods and their calibration, neutron energy spectra and fluxes outside the tokamak plasma chamber, history of neutron production in tokamaks, neutron emission and fusion power gain from JET and TFTR (the largest present-day tokamaks), and D-T neutron production from burnup of D-D tritons. This paper also discusses the prospects for future tokamak neutron production and potential applications of tokamak neutron sources. 100 refs., 16 figs., 4 tabs.

  17. Improved proton computed tomography by dual modality image reconstruction

    SciTech Connect (OSTI)

    Hansen, David C., E-mail: dch@ki.au.dk; Bassler, Niels [Experimental Clinical Oncology, Aarhus University, 8000 Aarhus C (Denmark)] [Experimental Clinical Oncology, Aarhus University, 8000 Aarhus C (Denmark); Petersen, Jørgen Breede Baltzer [Medical Physics, Aarhus University Hospital, 8000 Aarhus C (Denmark)] [Medical Physics, Aarhus University Hospital, 8000 Aarhus C (Denmark); Sørensen, Thomas Sangild [Computer Science, Aarhus University, 8000 Aarhus C, Denmark and Clinical Medicine, Aarhus University, 8200 Aarhus N (Denmark)] [Computer Science, Aarhus University, 8000 Aarhus C, Denmark and Clinical Medicine, Aarhus University, 8200 Aarhus N (Denmark)

    2014-03-15T23:59:59.000Z

    Purpose: Proton computed tomography (CT) is a promising image modality for improving the stopping power estimates and dose calculations for particle therapy. However, the finite range of about 33 cm of water of most commercial proton therapy systems limits the sites that can be scanned from a full 360° rotation. In this paper the authors propose a method to overcome the problem using a dual modality reconstruction (DMR) combining the proton data with a cone-beam x-ray prior. Methods: A Catphan 600 phantom was scanned using a cone beam x-ray CT scanner. A digital replica of the phantom was created in the Monte Carlo code Geant4 and a 360° proton CT scan was simulated, storing the entrance and exit position and momentum vector of every proton. Proton CT images were reconstructed using a varying number of angles from the scan. The proton CT images were reconstructed using a constrained nonlinear conjugate gradient algorithm, minimizing total variation and the x-ray CT prior while remaining consistent with the proton projection data. The proton histories were reconstructed along curved cubic-spline paths. Results: The spatial resolution of the cone beam CT prior was retained for the fully sampled case and the 90° interval case, with the MTF = 0.5 (modulation transfer function) ranging from 5.22 to 5.65?linepairs/cm. In the 45° interval case, the MTF = 0.5 dropped to 3.91?linepairs/cm For the fully sampled DMR, the maximal root mean square (RMS) error was 0.006 in units of relative stopping power. For the limited angle cases the maximal RMS error was 0.18, an almost five-fold improvement over the cone beam CT estimate. Conclusions: Dual modality reconstruction yields the high spatial resolution of cone beam x-ray CT while maintaining the improved stopping power estimation of proton CT. In the case of limited angles, the use of prior image proton CT greatly improves the resolution and stopping power estimate, but does not fully achieve the quality of a 360° proton CT scan.

  18. Dose dependence of mechanical properties in tantalum and tantalum alloys after low temperature irradiation

    SciTech Connect (OSTI)

    Byun, Thak Sang [ORNL

    2008-01-01T23:59:59.000Z

    The dose dependence of mechanical properties was investigated for tantalum and tantalum alloys after low temperature irradiation. Miniature tensile specimens of three pure tantalum metals, ISIS Ta, Aesar Ta1, Aesar Ta2, and one tantalum alloy, Ta-1W, were irradiated by neutrons in the High Flux Isotope Reactor (HFIR) at ORNL to doses ranging from 0.00004 to 0.14 displacements per atom (dpa) in the temperature range 60 C 100 oC. Also, two tantalum-tungsten alloys, Ta-1W and Ta-10W, were irradiated by protons and spallation neutrons in the LANSCE facility at LANL to doses ranging from 0.7 to 7.5 dpa and from 0.7 to 25.2 dpa, respectively, in the temperature range 50 C 160 oC. Tensile tests were performed at room temperature and at 250oC at nominal strain rates of about 10-3 s-1. All neutron-irradiated materials underwent progressive irradiation hardening and loss of ductility with increasing dose. The ISIS Ta experienced embrittlement at 0.14 dpa, while the other metals retained significant necking ductility. Such a premature embrittlement in ISIS Ta is believed to be because of high initial oxygen concentrations picked up during a pre-irradiation anneal. The Ta-1W and Ta-10W specimens irradiated in spallation condition experienced prompt necking at yield since irradiation doses for those specimens were high ( 0.7 dpa). At the highest dose, 25.2 dpa, the Ta-10W alloy specimen broke with little necking strain. Among the test materials, the Ta-1W alloy displayed the best combination of strength and ductility. The plastic instability stress and true fracture stress were nearly independent of dose. Increasing test temperature decreased strength and delayed the onset of necking at yield.

  19. Neutron Absorbing Alloys

    DOE Patents [OSTI]

    Mizia, Ronald E. (Idaho Falls, ID); Shaber, Eric L. (Idaho Falls, ID); DuPont, John N. (Whitehall, PA); Robino, Charles V. (Albuquerque, NM); Williams, David B. (Bethlehem, PA)

    2004-05-04T23:59:59.000Z

    The present invention is drawn to new classes of advanced neutron absorbing structural materials for use in spent nuclear fuel applications requiring structural strength, weldability, and long term corrosion resistance. Particularly, an austenitic stainless steel alloy containing gadolinium and less than 5% of a ferrite content is disclosed. Additionally, a nickel-based alloy containing gadolinium and greater than 50% nickel is also disclosed.

  20. Solid state neutron detector array

    DOE Patents [OSTI]

    Seidel, J.G.; Ruddy, F.H.; Brandt, C.D.; Dulloo, A.R.; Lott, R.G.; Sirianni, E.; Wilson, R.O.

    1999-08-17T23:59:59.000Z

    A neutron detector array is capable of measuring a wide range of neutron fluxes. The array includes multiple semiconductor neutron detectors. Each detector has a semiconductor active region that is resistant to radiation damage. In one embodiment, the array preferably has a relatively small size, making it possible to place the array in confined locations. The ability of the array to detect a wide range of neutron fluxes is highly advantageous for many applications such as detecting neutron flux during start up, ramp up and full power of nuclear reactors. 7 figs.

  1. Solid state neutron detector array

    DOE Patents [OSTI]

    Seidel, John G. (Pittsburgh, PA); Ruddy, Frank H. (Monroeville, PA); Brandt, Charles D. (Mount Lebanon, PA); Dulloo, Abdul R. (Pittsburgh, PA); Lott, Randy G. (Pittsburgh, PA); Sirianni, Ernest (Monroeville, PA); Wilson, Randall O. (Greensburg, PA)

    1999-01-01T23:59:59.000Z

    A neutron detector array is capable of measuring a wide range of neutron fluxes. The array includes multiple semiconductor neutron detectors. Each detector has a semiconductor active region that is resistant to radiation damage. In one embodiment, the array preferably has a relatively small size, making it possible to place the array in confined locations. The ability of the array to detect a wide range of neutron fluxes is highly advantageous for many applications such as detecting neutron flux during start up, ramp up and full power of nuclear reactors.

  2. Reconstruction for proton computed tomography by tracing proton trajectories: A Monte Carlo study

    SciTech Connect (OSTI)

    Li Tianfang; Liang Zhengrong; Singanallur, Jayalakshmi V.; Satogata, Todd J.; Williams, David C.; Schulte, Reinhard W. [Departments of Radiology, Computer Science, and Physics and Astronomy, State University of New York at Stony Brook, Stony Brook, New York 11794 (United States); Department of Physics, Brookhaven National Laboratory, Upton, New York 11973 (United States); Santa Cruz Institute for Particle Physics, University of California at Santa Cruz, Santa Cruz, California 95064 (United States); Department of Radiation Medicine, Loma Linda University Medical Center, Loma Linda, California 92354 (United States)

    2006-03-15T23:59:59.000Z

    Proton computed tomography (pCT) has been explored in the past decades because of its unique imaging characteristics, low radiation dose, and its possible use for treatment planning and on-line target localization in proton therapy. However, reconstruction of pCT images is challenging because the proton path within the object to be imaged is statistically affected by multiple Coulomb scattering. In this paper, we employ GEANT4-based Monte Carlo simulations of the two-dimensional pCT reconstruction of an elliptical phantom to investigate the possible use of the algebraic reconstruction technique (ART) with three different path-estimation methods for pCT reconstruction. The first method assumes a straight-line path (SLP) connecting the proton entry and exit positions, the second method adapts the most-likely path (MLP) theoretically determined for a uniform medium, and the third method employs a cubic spline path (CSP). The ART reconstructions showed progressive improvement of spatial resolution when going from the SLP [2 line pairs (lp) cm{sup -1}] to the curved CSP and MLP path estimates (5 lp cm{sup -1}). The MLP-based ART algorithm had the fastest convergence and smallest residual error of all three estimates. This work demonstrates the advantage of tracking curved proton paths in conjunction with the ART algorithm and curved path estimates.

  3. Reformulating and Reconstructing Quantum Theory

    E-Print Network [OSTI]

    Lucien Hardy

    2011-08-25T23:59:59.000Z

    We provide a reformulation of finite dimensional quantum theory in the circuit framework in terms of mathematical axioms, and a reconstruction of quantum theory from operational postulates. The mathematical axioms for quantum theory are the following: [Axiom 1] Operations correspond to operators. [Axiom 2] Every complete set of physical operators corresponds to a complete set of operations. The following operational postulates are shown to be equivalent to these mathematical axioms: [P1] Sharpness. Associated with any given pure state is a unique maximal effect giving probability equal to one. This maximal effect does not give probability equal to one for any other pure state. [P2] Information locality. A maximal measurement on a composite system is effected if we perform maximal measurements on each of the components. [P3] Tomographic locality. The state of a composite system can be determined from the statistics collected by making measurements on the components. [P4] Compound permutability. There exists a compound reversible transformation on any system effecting any given permutation of any given maximal set of distinguishable states for that system. [P5] Sturdiness. Filters are non-flattening. Hence, from these postulates we can reconstruct all the usual features of quantum theory: States are represented by positive operators, transformations by completely positive trace non-increasing maps, and effects by positive operators. The Born rule (i.e. the trace rule) for calculating probabilitieso follows. A more detailed abstract is provided in the paper.

  4. Coated Fiber Neutron Detector Test

    SciTech Connect (OSTI)

    Lintereur, Azaree T.; Ely, James H.; Kouzes, Richard T.; Stromswold, David C.

    2009-10-23T23:59:59.000Z

    Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. The currently deployed radiation portal monitors (RPMs) from Ludlum and Science Applications International Corporation (SAIC) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large neutron detector. There is a declining supply of 3He in the world, and thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Reported here are the results of tests of the 6Li/ZnS(Ag)-coated non-scintillating plastic fibers option. This testing measured the required performance for neutron detection efficiency and gamma ray rejection capabilities of a system manufactured by Innovative American Technology (IAT).

  5. HDRMC, an accelerated Monte Carlo dose calculator for high dose rate brachytherapy with CT-compatible applicators

    SciTech Connect (OSTI)

    Chibani, Omar, E-mail: omar.chibani@fccc.edu; C-M Ma, Charlie [Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 (United States)] [Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 (United States)

    2014-05-15T23:59:59.000Z

    Purpose: To present a new accelerated Monte Carlo code for CT-based dose calculations in high dose rate (HDR) brachytherapy. The new code (HDRMC) accounts for both tissue and nontissue heterogeneities (applicator and contrast medium). Methods: HDRMC uses a fast ray-tracing technique and detailed physics algorithms to transport photons through a 3D mesh of voxels representing the patient anatomy with applicator and contrast medium included. A precalculated phase space file for the{sup 192}Ir source is used as source term. HDRM is calibrated to calculated absolute dose for real plans. A postprocessing technique is used to include the exact density and composition of nontissue heterogeneities in the 3D phantom. Dwell positions and angular orientations of the source are reconstructed using data from the treatment planning system (TPS). Structure contours are also imported from the TPS to recalculate dose-volume histograms. Results: HDRMC was first benchmarked against the MCNP5 code for a single source in homogenous water and for a loaded gynecologic applicator in water. The accuracy of the voxel-based applicator model used in HDRMC was also verified by comparing 3D dose distributions and dose-volume parameters obtained using 1-mm{sup 3} versus 2-mm{sup 3} phantom resolutions. HDRMC can calculate the 3D dose distribution for a typical HDR cervix case with 2-mm resolution in 5 min on a single CPU. Examples of heterogeneity effects for two clinical cases (cervix and esophagus) were demonstrated using HDRMC. The neglect of tissue heterogeneity for the esophageal case leads to the overestimate of CTV D90, CTV D100, and spinal cord maximum dose by 3.2%, 3.9%, and 3.6%, respectively. Conclusions: A fast Monte Carlo code for CT-based dose calculations which does not require a prebuilt applicator model is developed for those HDR brachytherapy treatments that use CT-compatible applicators. Tissue and nontissue heterogeneities should be taken into account in modern HDR brachytherapy planning.

  6. Dose measurements behind reduced shielding at the Texas A&M University variable energy cyclotron

    E-Print Network [OSTI]

    Kay, Douglas Carey

    1982-01-01T23:59:59.000Z

    the reduced shielding by measuring neutron and gamma ray dose rates. A listing of currently available beams that are included in the study is given in Table 1. The purpose of this study is to provide information that can be used to limit radiation... conducted into accelerator shielding. It is known that a shield which is adequate to attenuate the high energy neutron component of the incident radiation will be more than enough to contain the charged particle and gamma ray com- ponents (NCRP77...

  7. Parity Violating Measurements of Neutron Densities: Implications for Neutron Stars

    E-Print Network [OSTI]

    C. J. Horowitz; J. Piekarewicz

    2002-01-08T23:59:59.000Z

    Parity violating electron scattering can measure the neutron density of a heavy nucleus accurately and model independently. This is because the weak charge of the neutron is much larger then that of the proton. The Parity Radius Experiment (PREX) at Jefferson Laboratory aims to measure the root mean square neutron radius of $^{208}$Pb with an absolute accuracy of 1% ($\\pm 0.05$ Fm). This is more accurate then past measurements with hadronic probes, which all suffer from controversial strong interaction uncertainties. PREX should clearly resolve the neutron-rich skin. Furthermore, this benchmark value for $^{208}$Pb will provide a calibration for hadronic probes, such as proton scattering, which can then be used to measure neutron densities of many exotic nuclei. The PREX result will also have many implications for neutron stars. The neutron radius of Pb depends on the pressure of neutron-rich matter: the greater the pressure, the larger the radius as neutrons are pushed out against surface tension. The same pressure supports a neutron star against gravity. The Pb radius is sensitive to the equation of state at normal densities while the radius of a 1.4 solar mass neutron star also depends on the equation of state at higher densities. Measurements of the radii of a number of isolated neutron stars such as Geminga and RX J185635-3754 should soon improve significantly. By comparing the equation of state information from the radii of both Pb and neutron stars one can search for a softening of the high density equation of state from a phase transition to an exotic state. Possibilities include kaon condensates, strange quark matter or color superconductors.

  8. Reconstruction and Restoration of PET Images.

    E-Print Network [OSTI]

    Mosegaard, Klaus

    Reconstruction and Restoration of PET Images. Ph.D. Thesis Peter Alshede Philipsen LYNGBY 1998 IMM with reconstruction and restoration of Positron Emission Tomography (PET) images carried out at the Section of Digital contains a short introduction to PET imaging. The second part, chapters 2 to 4, describe the PET scanner

  9. Spectrum Sensing and Reconstruction for Cognitive Radio

    E-Print Network [OSTI]

    Qiu, Robert Caiming

    Spectrum Sensing and Reconstruction for Cognitive Radio Amanpreet S Saini, Zhen Hu, Robert Qiu with spectrum sensing and spectrum reconstruction under the umbrella of cognitive radio which is the smart radio to explore and exploit the free spectrum. Spectrum analyzer is used to emulate cognitive radio to do spectrum

  10. Template-based Reconstruction of Complex Refactorings

    E-Print Network [OSTI]

    Kim, Miryung

    Template-based Reconstruction of Complex Refactorings Kyle Prete, Napol Rachatasumrit, Nikita Sudan occurred be- tween two program versions can help programmers better understand code changes. Our survey using a template- based refactoring reconstruction approach--REF-FINDER ex- presses each refactoring

  11. Advanced Neutron Source radiological design criteria

    SciTech Connect (OSTI)

    Westbrook, J.L.

    1995-08-01T23:59:59.000Z

    The operation of the proposed Advanced Neutron Source (ANS) facility will present a variety of radiological protection problems. Because it is desired to design and operate the ANS according to the applicable licensing standards of the Nuclear Regulatory Commission (NRC), it must be demonstrated that the ANS radiological design basis is consistent not only with state and Department of Energy (DOE) and other usual federal regulations, but also, so far as is practicable, with NRC regulations and with recommendations of such organizations as the Institute of Nuclear Power Operations (INPO) and the Electric Power Research Institute (EPRI). Also, the ANS radiological design basis is in general to be consistent with the recommendations of authoritative professional and scientific organizations, specifically the National Council on Radiation Protection and Measurements (NCRP) and the International Commission on Radiological Protection (ICRP). As regards radiological protection, the principal goals of DOE regulations and guidance are to keep occupational doses ALARA [as low as (is) reasonably achievable], given the current state of technology, costs, and operations requirements; to control and monitor contained and released radioactivity during normal operation to keep public doses and releases to the environment ALARA; and to limit doses to workers and the public during accident conditions. Meeting these general design objectives requires that principles of dose reduction and of radioactivity control by employed in the design, operation, modification, and decommissioning of the ANS. The purpose of this document is to provide basic radiological criteria for incorporating these principles into the design of the ANS. Operations, modification, and decommissioning will be covered only as they are affected by design.

  12. Reconstruction of nonlinear wave propagation

    DOE Patents [OSTI]

    Fleischer, Jason W; Barsi, Christopher; Wan, Wenjie

    2013-04-23T23:59:59.000Z

    Disclosed are systems and methods for characterizing a nonlinear propagation environment by numerically propagating a measured output waveform resulting from a known input waveform. The numerical propagation reconstructs the input waveform, and in the process, the nonlinear environment is characterized. In certain embodiments, knowledge of the characterized nonlinear environment facilitates determination of an unknown input based on a measured output. Similarly, knowledge of the characterized nonlinear environment also facilitates formation of a desired output based on a configurable input. In both situations, the input thus characterized and the output thus obtained include features that would normally be lost in linear propagations. Such features can include evanescent waves and peripheral waves, such that an image thus obtained are inherently wide-angle, farfield form of microscopy.

  13. Weldon Spring historical dose estimate

    SciTech Connect (OSTI)

    Meshkov, N.; Benioff, P.; Wang, J.; Yuan, Y.

    1986-07-01T23:59:59.000Z

    This study was conducted to determine the estimated radiation doses that individuals in five nearby population groups and the general population in the surrounding area may have received as a consequence of activities at a uranium processing plant in Weldon Spring, Missouri. The study is retrospective and encompasses plant operations (1957-1966), cleanup (1967-1969), and maintenance (1969-1982). The dose estimates for members of the nearby population groups are as follows. Of the three periods considered, the largest doses to the general population in the surrounding area would have occurred during the plant operations period (1957-1966). Dose estimates for the cleanup (1967-1969) and maintenance (1969-1982) periods are negligible in comparison. Based on the monitoring data, if there was a person residing continually in a dwelling 1.2 km (0.75 mi) north of the plant, this person is estimated to have received an average of about 96 mrem/yr (ranging from 50 to 160 mrem/yr) above background during plant operations, whereas the dose to a nearby resident during later years is estimated to have been about 0.4 mrem/yr during cleanup and about 0.2 mrem/yr during the maintenance period. These values may be compared with the background dose in Missouri of 120 mrem/yr.

  14. Analysis Approach and Data Package for Mayak Public Doses

    SciTech Connect (OSTI)

    Eslinger, Paul W.; Napier, Bruce A.

    2013-09-18T23:59:59.000Z

    Historical activities at facilities producing nuclear materials for weapons released radioactivity into the air and water. Past studies in the United States have evaluated the release, atmospheric transport and environmental accumulation of 131I from the nuclear facilities at Hanford in Washington State and the resulting dose to members of the public (Farris et al. 1994). A multi-year dose reconstruction effort (Mokrov et al. 2004) is also being conducted to produce representative dose estimates for members of the public living near Mayak, Russia, from atmospheric releases of 131I at the facilities of the Mayak Production Association. The approach to calculating individual doses to members of the public from historical releases of airborne 131I has the following general steps: • Construct estimates of releases 131I to the air from production facilities. • Model the transport of 131I in the air and subsequent deposition on the ground and vegetation. • Model the accumulation of 131I in soil, water and food products (environmental media). • Calculate the dose for an individual by matching the appropriate lifestyle and consumption data for the individual to the concentrations of 131I in environmental media at their residence location. A number of computer codes were developed to facilitate the study of airborne 131I emissions at Hanford. Of particular interest is DESCARTES code that modeled accumulation of 131I in environmental media (Miley et al. 1994). In addition, the CIDER computer code estimated annual doses to individuals (Eslinger et al. 1994) using the equations and parameters specific to Hanford (Snyder et al. 1994). Several of the computer codes developed to model 131I releases from Hanford are general enough to be used for other facilities. Additional codes have been developed, including the new individual dose code CiderF (Eslinger and Napier 2013), and applied to historical releases of 131I from Mayak. This document provides a data package that identifies computer code runs and associated input and output files prepared for the purpose of calculating doses to members of the public from atmospheric releases of 131I at the Mayak Production Association for the time period 1948 through 1972.

  15. Dose algorithm determination for the Los Alamos National Laboratory personnel dosimetry system

    SciTech Connect (OSTI)

    Patterson, J.M.

    1995-12-31T23:59:59.000Z

    One of the most important aspects of a TLD dosimetry system is the dose algorithm used to convert the signals from the badge reader to an estimate of a worker`s dose. It is now more important then ever to have an accurate algorithm to estimate dose well below regulatory limits. Dosimetry systems for DOE laboratories must meet minimum performance standards based on DOELAP criteria. The purpose of this paper is to describe the development of a dose algorithm for a new TLD dosimeter that has been developed at Los Alamos National Laboratories. It is expected that DOELAP testing will start in 1995. Initial results indicate that the system will be able to exceed the minimum performance criteria by a large margin. The enhanced ability of the dosimeter to determine beta, gamma, and neutron energies makes it very useful in the various radiation fields encountered at the laboratory.

  16. Porous material neutron detector

    DOE Patents [OSTI]

    Diawara, Yacouba (Oak Ridge, TN); Kocsis, Menyhert (Venon, FR)

    2012-04-10T23:59:59.000Z

    A neutron detector employs a porous material layer including pores between nanoparticles. The composition of the nanoparticles is selected to cause emission of electrons upon detection of a neutron. The nanoparticles have a maximum dimension that is in the range from 0.1 micron to 1 millimeter, and can be sintered with pores thereamongst. A passing radiation generates electrons at one or more nanoparticles, some of which are scattered into a pore and directed toward a direction opposite to the applied electrical field. These electrons travel through the pore and collide with additional nanoparticles, which generate more electrons. The electrons are amplified in a cascade reaction that occurs along the pores behind the initial detection point. An electron amplification device may be placed behind the porous material layer to further amplify the electrons exiting the porous material layer.

  17. Neutron Scattering Stiudies

    SciTech Connect (OSTI)

    Kegel, Gunter H.R.; Egan, James J

    2007-04-18T23:59:59.000Z

    This project covers four principal areas of research: Elastic and inelastic neutron scattering studies in odd-A terbium, thulium and other highly deformed nuclei near A=160 with special regard to interband transitions and to the investigation of the direct-interaction versus the compound-nucleus excitation process in these nuclei. Examination of new, fast photomultiplier tubes suitable for use in a miniaturized neutron-time-of-flight spectrometer. Measurement of certain inelastic cross sections of 238U. Determination of the multiplicity of prompt fission gamma rays in even-A fissile actinides. Energies and mean lives of fission isomers produced by fast fission of even-Z, even-A actinides. Study of the mean life of 7Be in different host matrices and its possible astro-physical significance.

  18. Fast neutron imaging device and method

    DOE Patents [OSTI]

    Popov, Vladimir; Degtiarenko, Pavel; Musatov, Igor V.

    2014-02-11T23:59:59.000Z

    A fast neutron imaging apparatus and method of constructing fast neutron radiography images, the apparatus including a neutron source and a detector that provides event-by-event acquisition of position and energy deposition, and optionally timing and pulse shape for each individual neutron event detected by the detector. The method for constructing fast neutron radiography images utilizes the apparatus of the invention.

  19. Novel Hybrid Monte Carlo/Deterministic Technique for Shutdown Dose Rate Analyses of Fusion Energy Systems

    SciTech Connect (OSTI)

    Ibrahim, Ahmad M [ORNL] [ORNL; Peplow, Douglas E. [ORNL] [ORNL; Peterson, Joshua L [ORNL] [ORNL; Grove, Robert E [ORNL] [ORNL

    2013-01-01T23:59:59.000Z

    The rigorous 2-step (R2S) method uses three-dimensional Monte Carlo transport simulations to calculate the shutdown dose rate (SDDR) in fusion reactors. Accurate full-scale R2S calculations are impractical in fusion reactors because they require calculating space- and energy-dependent neutron fluxes everywhere inside the reactor. The use of global Monte Carlo variance reduction techniques was suggested for accelerating the neutron transport calculation of the R2S method. The prohibitive computational costs of these approaches, which increase with the problem size and amount of shielding materials, inhibit their use in the accurate full-scale neutronics analyses of fusion reactors. This paper describes a novel hybrid Monte Carlo/deterministic technique that uses the Consistent Adjoint Driven Importance Sampling (CADIS) methodology but focuses on multi-step shielding calculations. The Multi-Step CADIS (MS-CADIS) method speeds up the Monte Carlo neutron calculation of the R2S method using an importance function that represents the importance of the neutrons to the final SDDR. Using a simplified example, preliminarily results showed that the use of MS-CADIS enhanced the efficiency of the neutron Monte Carlo simulation of an SDDR calculation by a factor of 550 compared to standard global variance reduction techniques, and that the increase over analog Monte Carlo is higher than 10,000.

  20. Role of Point Defects on the Reactivity of Reconstructed Anatase...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Point Defects on the Reactivity of Reconstructed Anatase Titanium Dioxide (001) Surface. Role of Point Defects on the Reactivity of Reconstructed Anatase Titanium Dioxide (001)...

  1. advanced surface reconstruction: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    adaptation of Neural Gas (NG) for reconstructing 3D- surfaces from point clouds. NG Zachmann, Gabriel 78 An Algebraic Approach to Surface Reconstruction from Gradient Fields Amit...

  2. ancestral state reconstruction: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    state is close to the true global state. We call the entropy of our reconstructed maximum entropy state the "reconstruction entropy", and we discuss its relation to...

  3. Neutron Science Center

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy:Nanowire Solar541,9337, 2011 at3,Neutron Scattering

  4. A gamma/neutron-discriminating, Cooled, Optically Stimulated Luminescence (COSL) dosemeter

    SciTech Connect (OSTI)

    Eschbach, P.A.; Miller, S.D.

    1992-07-01T23:59:59.000Z

    The Cooled Optically Stimulated Luminescence (COSL) of CaF{sub 2}:Mn (grain sizes from 0.1 to 100 microns) powder embedded in a hydrogenous matrix is reported as a function of fast-neutron dose. When all the CaF{sub 2}:Mn grains are interrogated at once, the COSL plastic dosemeters have a minimum detectable limit of 1 cSv fast neutrons; the gamma component from the bare {sup 252}cf exposure was determined with a separate dosemeter. We report here on a proton-recoil-based dosemeter that generates pulse height spectra, much like the scintillator of Hornyak, (2) to provide information on both the neutron and gamma dose.

  5. Why Use Neutrons For Research? | Neutron Science | ORNL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    better understand how biomass can be efficiently converted into fuel. Neutrons have many properties that make them ideal for certain types of research. Because of their unique...

  6. REVIEW OF NON-NEUTRON AND NEUTRON NUCLEAR DATA, 2004.

    SciTech Connect (OSTI)

    HOLDEN, N.E.

    2004-09-26T23:59:59.000Z

    Review articles are in preparation for the 2004 edition of the CRC Handbook of Chemistry and Physics dealing with the evaluation of both non-neutron and neutron nuclear data. Data on the discovery of element 110, Darmstadtium, and element 111 have been officially accepted, while data on element 11 8 have been withdrawn. Data to be presented include revised values for very short-lived nuclides, long-lived nuclides and beta-beta decay measurements. There has been a reassessment of the spontaneous fission (sf) half-lives, which distinguishes between sf decay half-lives and cluster decay half-lives and with cluster-fission decay. New measurements of isotopic abundance values for many elements will be discussed with an emphasis on the minor isotopes of interest for use in neutron activation analysis measurements. Neutron resonance integrals will be discussed emphasizing the differences between the calculated values obtained from the analytical integration over neutron resonances and the measured values in a neutron reactor-spectrum, which does not quite conform to the assumed 1/E neutron energy spectrum. The method used to determine the neutron resonance integral from measurement, using neutron activation analysis, will be discussed.

  7. Review of Non-Neutron and Neutron Nuclear Data, 2004

    SciTech Connect (OSTI)

    Holden, Norman E. [National Nuclear Data Center, Brookhaven National Laboratory, Upton, NY 11973-5000 (United States)

    2005-05-24T23:59:59.000Z

    Review articles are in preparation for the 2004 edition of the CRC Handbook of Chemistry and Physics dealing with the evaluation of both non-neutron and neutron nuclear data. Data on the discovery of element 110, Darmstadtium, and element 111 have been officially accepted, while data on element 118 have been withdrawn. Data to be presented include revised values for very short-lived nuclides, long-lived nuclides, and beta-beta decay measurements. There has been a reassessment of the spontaneous fission (sf) half-lives, which distinguishes between sf decay half-lives and cluster decay half-lives, and with cluster-fission decay. New measurements of isotopic abundance values for many elements will be discussed with an emphasis on the minor isotopes of interest for use in neutron activation analysis measurements. Neutron resonance integrals will be discussed emphasizing the differences between the calculated values obtained from the analytical integration over neutron resonances and the measured values in a neutron reactor-spectrum, which does not quite conform to the assumed 1/E neutron energy spectrum. The method used to determine the neutron resonance integral from measurement, using neutron activation analysis, will be discussed.

  8. Neutron cameras for ITER

    SciTech Connect (OSTI)

    Johnson, L.C.; Barnes, C.W.; Batistoni, P. [ITER San Diego Joint Work Site, La Jolla, CA (United States)] [and others

    1998-12-31T23:59:59.000Z

    Neutron cameras with horizontal and vertical views have been designed for ITER, based on systems used on JET and TFTR. The cameras consist of fan-shaped arrays of collimated flight tubes, with suitably chosen detectors situated outside the biological shield. The sight lines view the ITER plasma through slots in the shield blanket and penetrate the vacuum vessel, cryostat, and biological shield through stainless steel windows. This paper analyzes the expected performance of several neutron camera arrangements for ITER. In addition to the reference designs, the authors examine proposed compact cameras, in which neutron fluxes are inferred from {sup 16}N decay gammas in dedicated flowing water loops, and conventional cameras with fewer sight lines and more limited fields of view than in the reference designs. It is shown that the spatial sampling provided by the reference designs is sufficient to satisfy target measurement requirements and that some reduction in field of view may be permissible. The accuracy of measurements with {sup 16}N-based compact cameras is not yet established, and they fail to satisfy requirements for parameter range and time resolution by large margins.

  9. Dose Reconstruction Using Computational Modeling of Handling a Particular Arsenic-73/Arsenic-74 Source

    E-Print Network [OSTI]

    Stallard, Alisha M.

    2011-08-08T23:59:59.000Z

    ). The 0.511 MeV annihilation photons from positrons were included in the 74As photon source term. 22 0.0E+00 1.0E-02 2.0E-02 3.0E-02 4.0E-02 5.0E-02 6.0E-02 7.0E-02 8.0E-02 0.0E+00 2.0E-01 4.0E-01 6.0E-01 8.0E-01 1.0E+00 1.2E+00 1.4E...V (15.4%) 1204.3 keV (2.8%) 23 The source terms used for 73As photons, 74As photons, and 74As betas are shown in Figs. 26, 27 and 28, respectively. c As-73 2.3125E+10 Bq (625 mCi) photons c Disk source 1.905 cm diam / radius...

  10. Biological doses with template distribution patterns

    SciTech Connect (OSTI)

    Harrop, R. (Simon Fraer Univ., Burnaby, British Columbia); Haymond, H.R.; Nisar, A.; Syed, A.N.M.; Feder, B.H.; Neblett, D.L.

    1981-02-01T23:59:59.000Z

    Consideration of radiation dose rate effects emphasizes advantages of the template method for lateral distribution of multiple sources in treatment of laterally infiltrating gynecologic cancer, when compared to a conventional technique with colpostats. Biological doses in time dose fractionation (TDF), ret and reu units are calculated for the two treatment methods. With the template method the lateral dose (point B) is raised without significantly increasing the doses to the rectum and bladder, that is, relatively, the calculated biological doses at point A and B are more nearly equivalent and the doses to the rectum and bladder are significantly lower than the dose to point B.

  11. Ground-water contribution to dose from past Hanford Operations

    SciTech Connect (OSTI)

    Freshley, M.D.; Thorne, P.D.

    1992-08-01T23:59:59.000Z

    The Hanford Environmental Dose Reconstruction (HEDR) Project is being conducted to estimate radiation doses that populations and individuals could have received from Hanford Site operations from 1944 to the present. Four possible pathways by which radionuclides migrating in ground water on the Hanford Site could have reached the public have been identified: (1) through contaminated ground water migrating to the Columbia River; (2) through wells on or adjacent to the Hanford Site; (3) through wells next to the Columbia River downstream of Hanford that draw some or all of their water from the river (riparian wells); and (4) through atmospheric deposition resulting in contamination of a small watershed that, in turn, results in contamination of a shallow well or spring by transport in the ground water. These four pathways make up the ground-water pathway,'' which is the subject of this study. Assessment of the ground-water pathway was performed by (1) reviewing the existing extensive literature on ground water and ground-water monitoring at Hanford and (2) performing calculations to estimate radionuclide concentrations where no monitoring data were collected. Radiation doses that would result from exposure to these radionuclides were calculated.

  12. Measurement of neutron spectra generated from bombardment of 4 to 24 MeV protons on a thick {sup 9}Be target and estimation of neutron yields

    SciTech Connect (OSTI)

    Paul, Sabyasachi; Sahoo, G. S.; Tripathy, S. P., E-mail: sam.tripathy@gmail.com, E-mail: tripathy@barc.gov.in; Sunil, C.; Bandyopadhyay, T. [Health Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Sharma, S. C.; Ramjilal,; Ninawe, N. G.; Gupta, A. K. [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2014-06-15T23:59:59.000Z

    A systematic study on the measurement of neutron spectra emitted from the interaction of protons of various energies with a thick beryllium target has been carried out. The measurements were carried out in the forward direction (at 0° with respect to the direction of protons) using CR-39 detectors. The doses were estimated using the in-house image analyzing program autoTRAK-n, which works on the principle of luminosity variation in and around the track boundaries. A total of six different proton energies starting from 4 MeV to 24 MeV with an energy gap of 4 MeV were chosen for the study of the neutron yields and the estimation of doses. Nearly, 92% of the recoil tracks developed after chemical etching were circular in nature, but the size distributions of the recoil tracks were not found to be linearly dependent on the projectile energy. The neutron yield and dose values were found to be increasing linearly with increasing projectile energies. The response of CR-39 detector was also investigated at different beam currents at two different proton energies. A linear increase of neutron yield with beam current was observed.

  13. Demonstration of Emitted-Neutron Computed Tomography to Count Fuel Pins

    SciTech Connect (OSTI)

    Hausladen, Paul [ORNL] [ORNL; Blackston, Matthew A [ORNL] [ORNL; Brubaker, E. [Sandia National Laboratories (SNL)] [Sandia National Laboratories (SNL); Chichester, David [Idaho National Laboratory (INL)] [Idaho National Laboratory (INL); Marleau, P. [Sandia National Laboratories (SNL)] [Sandia National Laboratories (SNL); Newby, Robert Jason [ORNL] [ORNL

    2012-01-01T23:59:59.000Z

    In this paper, we report demonstration of emitted-neutron computed tomography using fast fission neutrons to infer the geometry of sources of special nuclear material (SNM) such as fuel pins. In a proof-of-concept measurement at the Idaho National Laboratory s (INL s) Zero Power Physics Reactor (ZPPR) facility, an array of unirradiated Pu MOX fuel rodlets in a soup can were imaged, and a bias defect consisting of a single rodlet containing Pu replaced by one containing depleted uranium (DU) was detected. The imaging system employed in the demonstration is based on a newly constructed array of pixelated neutron detectors that are suitable for arrangement in a close-packed imaging array and whose active volume consists of liquid scintillator EJ-309 which allows neutron-gamma discrimination via pulse shape to enable pure fast-neutron imaging. The imaging array was used along with a radial collimator aperture in order to perform high quality fast-neutron imaging where tomographic reconstruction of slices through an object resolve neutron sources similar in dimension to a fuel pellet, or about 1 cm. Measurements were performed at Oak Ridge National Laboratory (ORNL) with neutron sources in addition to those performed at the INL s ZPPR facility with Pu MOX fuel rodlets. An analogous capability to detect single-pin defects in spent fuel assemblies would be desirable, such as for safeguards verification measurements of spent fuel assemblies just prior to transferring them from the spent fuel cooling pool to long term dry cask storage. This paper describes the design and construction of the present imager, characterization measurements with neutron sources at ORNL, measurements with SNM at INL s ZPPR facility, and feasibility of building an analogous imager for spent fuel measurements.

  14. Demonstration of Emitted-Neutron Computed Tomography to Count Fuel Pins

    SciTech Connect (OSTI)

    P. A. Hausladen; M. A. Blackston; E. Brubaker; D. L. Chichester; P. Marleau; R. J. Newby

    2012-07-01T23:59:59.000Z

    In this paper, we report demonstration of emitted-neutron computed tomography using fast fission neutrons to infer the geometry of sources of special nuclear material (SNM) such as fuel pins. In a proof-of-concept measurement at the Idaho National Laboratory’s (INL’s) Zero Power Physics Reactor (ZPPR) facility, an array of unirradiated Pu MOX fuel rodlets in a soup can were imaged, and a bias defect consisting of a single rodlet containing Pu replaced by one containing depleted uranium (DU) was detected. The imaging system employed in the demonstration is based on a newly constructed array of pixelated neutron detectors that are suitable for arrangement in a close-packed imaging array and whose active volume consists of liquid scintillator EJ-309 which allows neutron-gamma discrimination via pulse shape to enable pure fast-neutron imaging. The imaging array was used along with a radial collimator aperture in order to perform high quality fast-neutron imaging where tomographic reconstruction of slices through an object resolve neutron sources similar in dimension to a fuel pellet, or about 1 cm. Measurements were performed at Oak Ridge National Laboratory (ORNL) with neutron sources in addition to those performed at the INL’s ZPPR facility with Pu MOX fuel rodlets. An analogous capability to detect single-pin defects in spent fuel assemblies would be desirable, such as for safeguards verification measurements of spent fuel assemblies just prior to transferring them from the spent fuel cooling pool to long term dry cask storage. This paper describes the design and construction of the present imager, characterization measurements with neutron sources at ORNL, measurements with SNM at INL’s ZPPR facility, and feasibility of building an analogous imager for spent fuel measurements.

  15. Neutron Detector Gamma Insensitivity Criteria

    SciTech Connect (OSTI)

    Kouzes, Richard T.; Ely, James H.; Lintereur, Azaree T.; Stephens, Daniel L.

    2009-10-21T23:59:59.000Z

    The shortage of 3He has triggered the search for an effective alternative neutron detection technology for radiation portal monitor applications. Any new detection technology must satisfy two basic criteria: 1) it must meet the neutron detection efficiency requirement, and 2) it must be insensitive to gamma ray interference at a prescribed level, while still meeting the neutron detection requirement. It is the purpose of this document to define this latter criterion.

  16. Characterization of the CR-39 neutron track etch dosimeter and evaluation of a combination CR-39/thermoluminescent dosimeter badge

    E-Print Network [OSTI]

    Hoover, Paul Steven

    1989-01-01T23:59:59.000Z

    . . . . . . . Objectives . THEORY 2 5 9 12 14 Charged Particle Interactions and Damage Track Formation Neutron Converters The Etching Process Background Effects The Quality Factor MATERIALS AND METHODS 14 16 18 21 22 31 CR-39 Supply . CR-39... effectiveness and used for calculating the dose equivalent (H) of exposed personnel, do not offer the same margin of safety for all radiations, including neutrons. The result is a proposed increase in applied Q values to assure comparable safety in all...

  17. Monte Carlo simulation of a Bonner sphere spectrometer for application to the determination of neutron field in the Experimental Advanced Superconducting Tokamak experimental hall

    SciTech Connect (OSTI)

    Hu, Z. M.; Xie, X. F.; Chen, Z. J.; Peng, X. Y.; Du, T. F.; Cui, Z. Q.; Ge, L. J.; Li, T.; Yuan, X.; Zhang, X.; Li, X. Q.; Zhang, G. H.; Chen, J. X.; Fan, T. S., E-mail: tsfan@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Hu, L. Q.; Zhong, G. Q.; Lin, S. Y.; Wan, B. N. [Institute of Plasma Physics, CAS, Hefei 230031 (China); Gorini, G. [Dipartimento di Fisica, Università di Milano-Bicocca, Milano 20126 (Italy); Istituto di Fisica del Plasma “P. Caldirola,” Milano 20126 (Italy)

    2014-11-15T23:59:59.000Z

    To assess the neutron energy spectra and the neutron dose for different positions around the Experimental Advanced Superconducting Tokamak (EAST) device, a Bonner Sphere Spectrometer (BSS) was developed at Peking University, with totally nine polyethylene spheres and a SP9 {sup 3}He counter. The response functions of the BSS were calculated by the Monte Carlo codes MCNP and GEANT4 with dedicated models, and good agreement was found between these two codes. A feasibility study was carried out with a simulated neutron energy spectrum around EAST, and the simulated “experimental” result of each sphere was obtained by calculating the response with MCNP, which used the simulated neutron energy spectrum as the input spectrum. With the deconvolution of the “experimental” measurement, the neutron energy spectrum was retrieved and compared with the preset one. Good consistence was found which offers confidence for the application of the BSS system for dose and spectrum measurements around a fusion device.

  18. CHRPR Neutron Board Replacement Manual

    SciTech Connect (OSTI)

    Erikson, Rebecca L.; Myjak, Mitchell J.

    2013-03-31T23:59:59.000Z

    This document will walk through the steps to exchange the neutron channel boards with gamma channel boards in the CHRPR box.

  19. Centrifugal quantum states of neutrons

    E-Print Network [OSTI]

    V. V. Nesvizhevsky; A. K. Petukhov; K. V. Protasov; A. Yu. Voronin

    2008-06-24T23:59:59.000Z

    We propose a method for observation of the quasi-stationary states of neutrons, localized near the curved mirror surface. The bounding effective well is formed by the centrifugal potential and the mirror Fermi-potential. This phenomenon is an example of an exactly solvable "quantum bouncer" problem that could be studied experimentally. It could provide a promising tool for studying fundamental neutron-matter interactions, as well as quantum neutron optics and surface physics effects. We develop formalism, which describes quantitatively the neutron motion near the mirror surface. The effects of mirror roughness are taken into account.

  20. Analytical applications for delayed neutrons

    SciTech Connect (OSTI)

    Eccleston, G.W.

    1983-01-01T23:59:59.000Z

    Analytical formulations that describe the time dependence of neutron populations in nuclear materials contain delayed-neutron dependent terms. These terms are important because the delayed neutrons, even though their yields in fission are small, permit control of the fission chain reaction process. Analytical applications that use delayed neutrons range from simple problems that can be solved with the point reactor kinetics equations to complex problems that can only be solved with large codes that couple fluid calculations with the neutron dynamics. Reactor safety codes, such as SIMMER, model transients of the entire reactor core using coupled space-time neutronics and comprehensive thermal-fluid dynamics. Nondestructive delayed-neutron assay instruments are designed and modeled using a three-dimensional continuous-energy Monte Carlo code. Calculations on high-burnup spent fuels and other materials that contain a mix of uranium and plutonium isotopes require accurate and complete information on the delayed-neutron periods, yields, and energy spectra. A continuing need exists for delayed-neutron parameters for all the fissioning isotopes.

  1. SU-E-T-304: Study of Secondary Neutrons From Uniform Scanning Proton Beams

    SciTech Connect (OSTI)

    Islam, M [Lawrence Cancer Center, KS (United States); Zheng, Y [Procure Proton Therapy Center, Oklahoma City, OK (United States); Benton, E [Oklahoma State University, Stillwater, OK (United States)

    2014-06-01T23:59:59.000Z

    Purpose: Secondary neutrons are unwanted byproducts from proton therapy and exposure from secondary radiation during treatment could increase risk of developing a secondary cancer later in a patient's lifetime. The purpose of this study is to investigate secondary neutrons from uniform scanning proton beams under various beam conditions using both measurements and Monte Carlo simulations. Methods: CR-39 Plastic Track Nuclear Detectors (PNTD) were used for the measurement. CR-39 PNTD has tissue like sensitivity to the secondary neutrons but insensitive to the therapeutic protons. In this study, we devised two experimental conditions: a) hollow-phantom; phantom is bored with a hollow cylinder along the direction of the beam so that the primary proton passes through the phantom without interacting with the phantom material, b) cylindrical-phantom; a solid cylinder of diameter close to the beam diameter is placed along the beam path. CR-39 PNTDs were placed laterally inside a 60X20X35 cm3 phantom (hollow-phantom) and in air (cylindrical-phantom) at various angles with respect to the primary beam axis. We studied for three different proton energies (78 MeV, 162 MeV and 226 MeV), using a 4 cm modulation width and 5cm diameter brass aperture for the entire experiment and simulation. A comparison of the experiment was performed using the Monte Carlo code FLUKA. Results: The measured secondary neutron dose equivalent per therapeutic primary proton dose (H/D) ranges from 2.1 ± 0.2 to 25.42 ± 2.3 mSv/Gy for the hollow phantom study, and 2.7 ± 0.3 to 46.4 ± 3.4 mSv/Gy for the cylindrical phantom study. Monte Carlo simulations predicated neutron dose equivalent from measurements within a factor of 5. Conclusion: The study suggests that the production of external neutrons is significantly higher than the production of internal neutrons.

  2. AGING FACILITY WORKER DOSE ASSESSMENT

    SciTech Connect (OSTI)

    R.L. Thacker

    2005-03-24T23:59:59.000Z

    The purpose of this calculation is to estimate radiation doses received by personnel working in the Aging Facility performing operations to transfer aging casks to the aging pads for thermal and logistical management, stage empty aging casks, and retrieve aging casks from the aging pads for further processing in other site facilities. Doses received by workers due to aging cask surveillance and maintenance operations are also included. The specific scope of work contained in this calculation covers both collective doses and individual worker group doses on an annual basis, and includes the contributions due to external and internal radiation from normal operation. There are no Category 1 event sequences associated with the Aging Facility (BSC 2004 [DIRS 167268], Section 7.2.1). The results of this calculation will be used to support the design of the Aging Facility and to provide occupational dose estimates for the License Application. The calculations contained in this document were developed by Environmental and Nuclear Engineering of the Design and Engineering Organization and are intended solely for the use of the Design and Engineering Organization in its work regarding facility operation. Yucca Mountain Project personnel from the Environmental and Nuclear Engineering should be consulted before use of the calculations for purposes other than those stated herein or use by individuals other than authorized personnel in Environmental and Nuclear Engineering.

  3. Full Jet Reconstruction in Heavy Ion Collisions

    E-Print Network [OSTI]

    Sevil Salur

    2009-09-16T23:59:59.000Z

    Full jet reconstruction has traditionally been thought to be difficult in heavy ion events due to large multiplicity backgrounds. The search for new physics in high luminosity p+p collisions at the LHC similarly requires the precise measurement of jets over large backgrounds caused by pile up; this has motivated the development of a new generation of jet reconstruction algorithms which are also applicable in the heavy ion environment. We review the latest results on jet-medium interactions as seen in A+A collisions at RHIC, focusing on the new techniques for full jet reconstruction.

  4. Neutron-deuteron breakup and quasielastic scattering

    E-Print Network [OSTI]

    Ohlson, Alice Elisabeth

    2009-01-01T23:59:59.000Z

    Quasielastic scattering and deuteron breakup in the 200 MeV region is studied by impinging a pulsed neutron beam on a deuterium target at the Weapons Neutron Research facility at the Los Alamos Neutron Science Center. The ...

  5. Requirements, possible alternatives & international NEUTRON SCATTERING

    E-Print Network [OSTI]

    Dimeo, Robert M.

    Requirements, possible alternatives & international NEUTRON SCATTERING DETECTORS for Rob Dimeo NIST neutron scattering instruments are the most demanding require background low #12;#12;The Helium-3 Supply Crisis ­ Alternative Techniques to Helium-3 based Detectors for Neutron Scattering Applications

  6. New neutron physics using spallation sources

    SciTech Connect (OSTI)

    Bowman, C.D.

    1988-01-01T23:59:59.000Z

    The extraordinary neutron intensities available from the new spallation pulsed neutron sources open up exciting opportunities for basic and applied research in neutron nuclear physics. The energy range of neutron research which is being explored with these sources extends from thermal energies to almost 800 MeV. The emphasis here is on prospective experiments below 100 keV neutron energy using the intense neutron bursts produced by the Proton Storage Ring (PSR) at Los Alamos. 30 refs., 10 figs.

  7. Measuring the Neutron's Mean Square Charge Radius Using Neutron Interferometry

    E-Print Network [OSTI]

    F. E. Wietfeldt; M. Huber; T. C. Black; H. Kaiser; M. Arif; D. L. Jacobson; S. A. Werner

    2005-09-14T23:59:59.000Z

    The neutron is electrically neutral, but its substructure consists of charged quarks so it may have an internal charge distribution. In fact it is known to have a negative mean square charge radius (MSCR), the second moment of the radial charge density. In other words the neutron has a positive core and negative skin. In the first Born approximation the neutron MSCR can be simply related to the neutron-electron scattering length b_ne. In the past this important quantity has been extracted from the energy dependence of the total transmission cross-section of neutrons on high-Z targets, a very difficult and complicated process. A few years ago S.A. Werner proposed a novel approach to measuring b_ne from the neutron's dynamical phase shift in a perfect crystal close to the Bragg condition. We are conducting an experiment based on this method at the NIST neutron interferometer which may lead to a five-fold improvement in precision of b_ne and hence the neutron MSCR.

  8. Direct observation of quark-hadron duality in the free neutron F_2 structure function

    E-Print Network [OSTI]

    Niculescu, I; Melnitchouk, W; Arrington, J; Christy, M E; Ent, R; Griffioen, K A; Kalantarians, N; Keppel, C E; Kuhn, S; Tkachenko, S; Zhang, J

    2015-01-01T23:59:59.000Z

    Using data from the recent BONuS experiment at Jefferson Lab, which utilized a novel spectator tagging technique to extract the inclusive electron-free neutron scattering cross section, we obtain the first direct observation of quark-hadron duality in the neutron F_2 structure function. The data are used to reconstruct the lowest few (N=2, 4 and 6) moments of F_2 in the three prominent nucleon resonance regions, as well as the moments integrated over the entire resonance region. Comparison with moments computed from global parametrizations of parton distribution functions suggest that quark--hadron duality holds locally for the neutron in the second and third resonance regions down to Q^2 ~ 1 GeV^2, with violations possibly up to 20% observed in the first resonance region.

  9. Direct observation of quark-hadron duality in the free neutron F_2 structure function

    E-Print Network [OSTI]

    I. Niculescu; G. Niculescu; W. Melnitchouk; J. Arrington; M. E. Christy; R. Ent; K. A. Griffioen; N. Kalantarians; C. E. Keppel; S. Kuhn; S. Tkachenko; J. Zhang

    2015-01-09T23:59:59.000Z

    Using data from the recent BONuS experiment at Jefferson Lab, which utilized a novel spectator tagging technique to extract the inclusive electron-free neutron scattering cross section, we obtain the first direct observation of quark-hadron duality in the neutron F_2 structure function. The data are used to reconstruct the lowest few (N=2, 4 and 6) moments of F_2 in the three prominent nucleon resonance regions, as well as the moments integrated over the entire resonance region. Comparison with moments computed from global parametrizations of parton distribution functions suggest that quark--hadron duality holds locally for the neutron in the second and third resonance regions down to Q^2 ~ 1 GeV^2, with violations possibly up to 20% observed in the first resonance region.

  10. Neutron Multiplicity Measurements With 3He Alternative: Straw Neutron Detectors

    SciTech Connect (OSTI)

    Mukhopadhyay, Sanjoy

    2015-01-01T23:59:59.000Z

    Counting neutrons emitted by special nuclear material (SNM) and differentiating them from the background neutrons of various origins is the most effective passive means of detecting SNM. Unfortunately, neutron detection, counting, and partitioning in a maritime environment are complex due to the presence of high-multiplicity spallation neutrons (commonly known as ‘‘ship effect ’’) and to the complicated nature of the neutron scattering in that environment. A prototype neutron detector was built using 10B as the converter in a special form factor called ‘‘straws’’ that would address the above problems by looking into the details of multiplicity distributions of neutrons originating from a fissioning source. This paper describes the straw neutron multiplicity counter (NMC) and assesses the performance with those of a commercially available fission meter. The prototype straw neutron detector provides a large-area, efficient, lightweight, more granular (than fission meter) neutron-responsive detection surface (to facilitate imaging) to enhance the ease of application of fission meters. Presented here are the results of preliminary investigations, modeling, and engineering considerations leading to the construction of this prototype. This design is capable of multiplicity and Feynman variance measurements. This prototype may lead to a near-term solution to the crisis that has arisen from the global scarcity of 3He by offering a viable alternative to fission meters. This paper describes the work performed during a 2-year site-directed research and development (SDRD) project that incorporated straw detectors for neutron multiplicity counting. The NMC is a two-panel detector system. We used 10B (in the form of enriched boron carbide: 10B4C) for neutron detection instead of 3He. In the first year, the project worked with a panel of straw neutron detectors, investigated its characteristics, and developed a data acquisition (DAQ) system to collect neutron multiplicity information from spontaneous fission sources using a single panel consisting of 60 straws equally distributed over three rows in high-density polyethylenemoderator. In the following year, we developed the field-programmable gate array and associated DAQ software. This SDRD effort successfully produced a prototype NMC with*33% detection efficiency compared to a commercial fission meter.

  11. Time-resolved neutron imaging at ANTARES cold neutron beamline

    E-Print Network [OSTI]

    Tremsin, A S; Tittelmeier, K; Schillinger, B; Schulz, M; Lerche, M; Feller, W B

    2015-01-01T23:59:59.000Z

    In non-destructive evaluation with X-rays light elements embedded in dense, heavy (or high-Z) matrices show little contrast and their structural details can hardly be revealed. Neutron radiography, on the other hand, provides a solution for those cases, in particular for hydrogenous materials, owing to the large neutron scattering cross section of hydrogen and uncorrelated dependency of neutron cross section on the atomic number. The majority of neutron imaging experiments at the present time is conducted with static objects mainly due to the limited flux intensity of neutron beamline facilities and sometimes due to the limitations of the detectors. However, some applications require the studies of dynamic phenomena and can now be conducted at several high intensity beamlines such as the recently rebuilt ANTARES beam line at the FRM-II reactor. In this paper we demonstrate the capabilities of time resolved imaging for repetitive processes, where different phases of the process can be imaged simultaneously and...

  12. HFIR Experiment Facilities | ORNL Neutron Sciences

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Scattering Neutron Scattering Facilities at HFIR The fully instrumented HFIR will eventually include 15 state-of-the-art neutron scattering instruments, seven of which will be...

  13. Search for: "neutron scattering" | DOE PAGES

    Office of Scientific and Technical Information (OSTI)

    neutron scattering" Find + Advanced Search Advanced Search All Fields: "neutron scattering" Title: Full Text: Bibliographic Data: Creator Author: Name Name ORCID Search...

  14. 11th LANSCE School on Neutron Scattering

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    11th LANSCE School on Neutron Scattering LANSCE 11th LANSCE School on Neutron Scattering Home Abstract Lecturers Lecturer Abstracts Hands-On Experiments Free Day About the...

  15. LANSCE | International Collaboration on Advanced Neutron Sources...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    LINAC Outreach Affiliations Visiting LANSCE Facilities Isotope Production Facility Lujan Neutron Scattering Center Materials Test Station Proton Radiography Ultra-Cold Neutrons...

  16. Quasifree photoproduction of $?$ mesons off protons and neutrons

    E-Print Network [OSTI]

    A2 Collaboration; D. Werthmüller; L. Witthauer; I. Keshelashvili; P. Aguar-Bartolomé; J. Ahrens; J. R. M. Annand; H. J. Arends; K. Bantawa; R. Beck; V. Bekrenev; A. Braghieri; D. Branford; W. J. Briscoe; J. Brudvik; S. Cherepnya; S. Costanza; B. Demissie; M. Dieterle; E. J. Downie; P. Drexler; L. V. Fil'kov; A. Fix; D. I. Glazier; D. Hamilton; E. Heid; D. Hornidge; D. Howdle; G. M. Huber; I. Jaegle; O. Jahn; T. C. Jude; A. Käser; V. L. Kashevarov; R. Kondratiev; M. Korolija; S. P. Kruglov; B. Krusche; A. Kulbardis; V. Lisin; K. Livingston; I. J. D. MacGregor; Y. Maghrbi; J. Mancell; D. M. Manley; Z. Marinides; M. Martinez; J. C. McGeorge; E. F. McNicoll; V. Metag; D. G. Middleton; A. Mushkarenkov; B. M. K. Nefkens; A. Nikolaev; R. Novotny; M. Oberle; M. Ostrick; P. B. Otte; B. Oussena; P. Pedroni; F. Pheron; A. Polonski; S. N. Prakhov; J. Robinson; G. Rosner; T. Rostomyan; S. Schumann; M. H. Sikora; D. Sober; A. Starostin; I. Supek; M. Thiel; A. Thomas; M. Unverzagt; D. P. Watts

    2014-07-25T23:59:59.000Z

    Differential and total cross sections for the quasifree reactions $\\gamma p\\rightarrow\\eta p$ and $\\gamma n\\rightarrow\\eta n$ have been determined at the MAMI-C electron accelerator using a liquid deuterium target. Photons were produced via bremsstrahlung from the 1.5 GeV incident electron beam and energy-tagged with the Glasgow photon tagger. Decay photons of the neutral decay modes $\\eta\\rightarrow 2\\gamma$ and $\\eta\\rightarrow 3\\pi^0 \\rightarrow 6\\gamma$ and coincident recoil nucleons were detected in a combined setup of the Crystal Ball and the TAPS calorimeters. The $\\eta$-production cross sections were measured in coincidence with recoil protons, recoil neutrons, and in an inclusive mode without a condition on recoil nucleons, which allowed a check of the internal consistency of the data. The effects from nuclear Fermi motion were removed by a kinematic reconstruction of the final-state invariant mass and possible nuclear effects on the quasifree cross section were investigated by a comparison of free and quasifree proton data. The results, which represent a significant improvement in statistical quality compared to previous measurements, agree with the known neutron-to-proton cross-section ratio in the peak of the $S_{11}(1535)$ resonance and confirm a peak in the neutron cross section, which is absent for the proton, at a center-of-mass energy $W = (1670\\pm 5)$ MeV with an intrinsic width of $\\Gamma\\approx 30$ MeV.

  17. Computing - Reconstructing neurons ... | ornl.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    how scientists digitally reconstruct and analyze individual neurons in the human brain. Led by the Allen Institute for Brain Science, the BigNeuron project aims to create a...

  18. Sparse Signal Reconstruction via Iterative Support Detection

    E-Print Network [OSTI]

    2010-07-04T23:59:59.000Z

    Sep 29, 2009 ... and a reduced requirement on the number of measurements .... (Throughout this paper, ¯x is used to denote the true signal to reconstruct.) ...... which include sparse Gaussian signals and certain power–law decaying signals.

  19. Precision Muon Reconstruction in Double Chooz

    E-Print Network [OSTI]

    Double Chooz collaboration; Y. Abe; J. C. dos Anjos; J. C. Barriere; E. Baussan; I. Bekman; M. Bergevin; T. J. C. Bezerra; L. Bezrukov; E. Blucher; C. Buck; J. Busenitz; A. Cabrera; E. Caden; L. Camilleri; R. Carr; M. Cerrada; P. -J. Chang; E. Chauveau; P. Chimenti; A. P. Collin; E. Conover; J. M. Conrad; J. I. Crespo-Anadón; K. Crum; A. Cucoanes; E. Damon; J. V. Dawson; D. Dietrich; Z. Djurcic; M. Dracos; M. Elnimr; A. Etenko; M. Fallot; F. von Feilitzsch; J. Felde; S. M. Fernandes; V. Fischer; D. Franco; M. Franke; H. Furuta; I. Gil-Botella; L. Giot; M. Göger-Neff; L. F. G. Gonzalez; L. Goodenough; M. C. Goodman; C. Grant; N. Haag; T. Hara; J. Haser; M. Hofmann; G. A. Horton-Smith; A. Hourlier; M. Ishitsuka; J. Jochum; C. Jollet; F. Kaether; L. N. Kalousis; Y. Kamyshkov; D. M. Kaplan; T. Kawasaki; E. Kemp; H. de Kerret; D. Kryn; M. Kuze; T. Lachenmaier; C. E. Lane; T. Lasserre; A. Letourneau; D. Lhuillier; H. P. Lima Jr; M. Lindner; J. M. López-Casta no; J. M. LoSecco; B. Lubsandorzhiev; S. Lucht; J. Maeda; C. Mariani; J. Maricic; J. Martino; T. Matsubara; G. Mention; A. Meregaglia; T. Miletic; R. Milincic; A. Minotti; Y. Nagasaka; Y. Nikitenko; P. Novella; M. Obolensky; L. Oberauer; A. Onillon; A. Osborn; C. Palomares; I. M. Pepe; S. Perasso; P. Pfahler; A. Porta; G. Pronost; J. Reichenbacher; B. Reinhold; M. Röhling; R. Roncin; S. Roth; B. Rybolt; Y. Sakamoto; R. Santorelli; A. C. Schilithz; S. Schönert; S. Schoppmann; M. H. Shaevitz; R. Sharankova; S. Shimojima; V. Sibille; V. Sinev; M. Skorokhvatov; E. Smith; J. Spitz; A. Stahl; I. Stancu; L. F. F. Stokes; M. Strait; A. Stüken; F. Suekane; S. Sukhotin; T. Sumiyoshi; Y. Sun; R. Svoboda; K. Terao; A. Tonazzo; H. H. Trinh Thi; G. Valdiviesso; N. Vassilopoulos; C. Veyssiere; M. Vivier; S. Wagner; H. Watanabe; C. Wiebusch; L. Winslow; M. Wurm; G. Yang; F. Yermia; V. Zimmer

    2014-08-15T23:59:59.000Z

    We describe a muon track reconstruction algorithm for the reactor anti-neutrino experiment Double Chooz. The Double Chooz detector consists of two optically isolated volumes of liquid scintillator viewed by PMTs, and an Outer Veto above these made of crossed scintillator strips. Muons are reconstructed by their Outer Veto hit positions along with timing information from the other two detector volumes. All muons are fit under the hypothesis that they are through-going and ultrarelativistic. If the energy depositions suggest that the muon may have stopped, the reconstruction fits also for this hypothesis and chooses between the two via the relative goodness-of-fit. In the ideal case of a through-going muon intersecting the center of the detector, the resolution is ~40 mm in each transverse dimension. High quality muon reconstruction is an important tool for reducing the impact of the cosmogenic isotope background in Double Chooz.

  20. EQUILIBRIUM RECONSTRUCTION ITERATION FLOW-CHART

    E-Print Network [OSTI]

    EQUILIBRIUM RECONSTRUCTION ITERATION FLOW-CHART SUME AND 0 n GET 1 AND C0 j GET J1 AND 1 n GET 2 the total stored (kinetic + magnetic) energy density #12;TYPICAL FIELD CONFIGURATIONS acuum Field Low Beta

  1. SIMD studies in the LHCb reconstruction software

    E-Print Network [OSTI]

    Campora Perez, D H

    2015-01-01T23:59:59.000Z

    During the data taking process in the LHC at CERN, millions of collisions are recorded every second by the LHCb Detector. The LHCb Online computing farm, counting around 15000 cores, is dedicated to the reconstruction of the events in real-time, in order to filter those with interesting Physics. The ones kept are later analysed $Offline$ in a more precise fashion on the Grid. This imposes very stringent requirements on the reconstruction software, which has to be as efficient as possible. Modern CPUs support so-called vector-extensions, which extend their Instruction Sets, allowing for concurrent execution across functional units. Several libraries expose the Single Instruction Multiple Data programming paradigm to issue these instructions. The use of vectorisation in our codebase can provide performance boosts, leading ultimately to Physics reconstruction enhancements. In this paper, we present vectorisation studies of significant reconstruction algorithms. A variety of vectorisation libraries are analysed a...

  2. Use of root in vehicular accident reconstruction

    E-Print Network [OSTI]

    Scurlock, Bob

    2011-01-01T23:59:59.000Z

    The purpose of this article is to introduce the reader to the ROOT data analysis software package, and demonstrate how it may be used to complement one's accident reconstruction analyses.

  3. Tissue responses to low protracted doses of high let radiations or photons: Early and late damage relevant to radio-protective countermeasures

    SciTech Connect (OSTI)

    Ainsworth, E.J.; Afzal, S.M.J.; Crouse, D.A.; Hanson, W.R.; Fry, R.J.M.

    1988-01-01T23:59:59.000Z

    Early and late murine tissue responses to single or fractionated low doses of heavy charged particles, fission-spectrum neutrons or gamma rays are considered. Damage to the hematopoietic system is emphasized, but results on acute lethality, host response to challenge with transplanted leukemia cells and life-shortening are presented. Low dose rates per fraction were used in some neutron experiments. Split-dose lethality studies (LD 50/30) with fission neutrons indicated greater accumulation of injury during a 9 fraction course (over 17 days) than was the case for ..gamma..-radiation. When total doses of 96 or 247 cGy of neutrons or ..gamma.. rays were given as a single dose or in 9 fractions, a significant sparing effect on femur CFU-S depression was observed for both radiation qualities during the first 11 days, but there was not an earlier return to normal with dose fractionation. During the 9 fraction sequence, a significant sparing effect of low dose rate on CFU-S depression was observed in both neutron and ..gamma..-irradiated mice. CFU-S content at the end of the fractionation sequence did not correlate with measured LD 50/30. Sustained depression of femur and spleen CFU-S and a significant thrombocytopenia were observed when a total neutron dose of 240 cGy was given in 72 fractions over 24 weeks at low dose rates. The temporal aspects of CFU-S repopulation were different after a single versus fractionated neutron doses. The sustained reduction in the size of the CFU-S population was accompanied by an increase in the fraction in DNA synthesis. The proliferation characteristics and effects of age were different for radial CFU-S population closely associated with bone, compared with the axial population that can be readily aspirated from the femur. In aged irradiated animals, the CFU-S proliferation/redistribution response to typhoid vaccine showed both an age and radiation effect. 63 refs., 6 figs., 7 tabs.

  4. Physics of Neutron Star Crusts

    E-Print Network [OSTI]

    N. Chamel; P. Haensel

    2008-12-20T23:59:59.000Z

    The physics of neutron star crusts is vast, involving many different research fields, from nuclear and condensed matter physics to general relativity. This review summarizes the progress, which has been achieved over the last few years, in modeling neutron star crusts, both at the microscopic and macroscopic levels. The confrontation of these theoretical models with observations is also briefly discussed.

  5. PSF reconstruction for NAOS-CONICA

    E-Print Network [OSTI]

    Yann Clénet; Markus Kasper; Eric Gendron; Thierry Fusco; Gérard Rousset; Damien Gratadour; Christopher Lidman; Olivier Marco; Nancy Ageorges; Sebastian Egner

    2006-07-12T23:59:59.000Z

    Adaptive optics (AO) allows one to derive the point spread function (PSF) simultaneously to the science image, which is a major advantage in post-processing tasks such as astrometry/photometry or deconvolution. Based on the algorithm of \\citet{veran97}, PSF reconstruction has been developed for four different AO systems so far: PUEO, ALFA, Lick-AO and Altair. A similar effort is undertaken for NAOS/VLT in a collaboration between the group PHASE (Onera and Observatoire de Paris/LESIA) and ESO. In this paper, we first introduce two new algorithms that prevent the use of the so-called "$U\\_{ij}$ functions" to: (1) avoid the storage of a large amount of data (for both new algorithms), (2) shorten the PSF reconstruction computation time (for one of the two) and (3) provide an estimation of the PSF variability (for the other one). We then identify and explain issues in the exploitation of real-time Shack-Hartmann (SH) data for PSF reconstruction, emphasising the large impact of thresholding in the accuracy of the phase residual estimation. Finally, we present the data provided by the NAOS real-time computer (RTC) to reconstruct PSF ({\\em (1)} the data presently available, {\\em (2)} two NAOS software modifications that would provide new data to increase the accuracy of the PSF reconstruction and {\\em (3)} the tests of these modifications) and the PSF reconstruction algorithms we are developing for NAOS on that basis.

  6. Noise suppression in reconstruction of low-Z target megavoltage cone-beam CT images

    SciTech Connect (OSTI)

    Wang Jing; Robar, James; Guan Huaiqun [Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, Texas 75235 (United States); Departments of Radiation Oncology and Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, B3H1V7 (Canada); Department of Radiation Oncology, Saint Vincent Hospital, Worcester, Massachusetts 01608 (United States)

    2012-08-15T23:59:59.000Z

    Purpose: To improve the image contrast-to-noise (CNR) ratio for low-Z target megavoltage cone-beam CT (MV CBCT) using a statistical projection noise suppression algorithm based on the penalized weighted least-squares (PWLS) criterion. Methods: Projection images of a contrast phantom, a CatPhan{sup Registered-Sign} 600 phantom and a head phantom were acquired by a Varian 2100EX LINAC with a low-Z (Al) target and low energy x-ray beam (2.5 MeV) at a low-dose level and at a high-dose level. The projections were then processed by minimizing the PWLS objective function. The weighted least square (WLS) term models the noise of measured projection and the penalty term enforces the smoothing constraints of the projection image. The variance of projection data was chosen as the weight for the PWLS objective function and it determined the contribution of each measurement. An anisotropic quadratic form penalty that incorporates the gradient information of projection image was used to preserve edges during noise reduction. Low-Z target MV CBCT images were reconstructed by the FDK algorithm after each projection was processed by the PWLS smoothing. Results: Noise in low-Z target MV CBCT images were greatly suppressed after the PWLS projection smoothing, without noticeable sacrifice of the spatial resolution. Depending on the choice of smoothing parameter, the CNR of selected regions of interest in the PWLS processed low-dose low-Z target MV CBCT image can be higher than the corresponding high-dose image.Conclusion: The CNR of low-Z target MV CBCT images was substantially improved by using PWLS projection smoothing. The PWLS projection smoothing algorithm allows the reconstruction of high contrast low-Z target MV CBCT image with a total dose of as low as 2.3 cGy.

  7. Reconstructing top quark-antiquark events with one lost jet

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Demina, Regina [Univ. of Rochester, Rochester, NY (United States); Harel, Amnon [Univ. of Rochester, Rochester, NY (United States); Orbaker, Douglas [Univ. of Rochester, Rochester, NY (United States)

    2015-07-01T23:59:59.000Z

    We present a technique for reconstructing the kinematics of pair-produced top quarks that decay to a charged lepton, a neutrino and four final state quarks in the subset of events where only three jets are reconstructed. We present a figure of merit that allows for a fair comparison of reconstruction algorithms without requiring their calibration. The new reconstruction of events with only three jets is fully competitive with the full reconstruction typically used for four-jet events.

  8. Threshold irradiation dose for amorphization of silicon carbide

    SciTech Connect (OSTI)

    Snead, L.L.; Zinkle, S.J.

    1997-03-01T23:59:59.000Z

    The amorphization of silicon carbide due to ion and electron irradiation is reviewed with emphasis on the temperature-dependent critical dose for amorphization. The effect of ion mass and energy on the threshold dose for amorphization is summarized, showing only a weak dependence near room temperature. Results are presented for 0.56 MeV silicon ions implanted into single crystal 6H-SiC as a function of temperature and ion dose. From this, the critical dose for amorphization is found as a function of temperature at depths well separated from the implanted ion region. Results are compared with published data generated using electrons and xenon ions as the irradiating species. High resolution TEM analysis is presented for the Si ion series showing the evolution of elongated amorphous islands oriented such that their major axis is parallel to the free surface. This suggests that surface or strain effects may be influencing the apparent amorphization threshold. Finally, a model for the temperature threshold for amorphization is described using the Si ion irradiation flux and the fitted interstitial migration energy which was found to be {approximately}0.56eV. This model successfully explains the difference in the temperature dependent amorphization behavior of SiC irradiated with 0.56 MeV Si{sup +} at 1 x 10{sup -3} dpa/s and with fission neutrons irradiated at 1 x 10{sup -6} dpa/s irradiated to 15 dpa in the temperature range of {approximately}340{+-}10K.

  9. Bilateral implant reconstruction does not affect the quality of postmastectomy radiation therapy

    SciTech Connect (OSTI)

    Ho, Alice Y., E-mail: hoa1234@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Patel, Nisha [Drexel University College of Medicine, Philadelphia, PA (United States); Ohri, Nisha [Department of Radiation Oncology, Mount Sinai School of Medicine, New York, NY (United States); Morrow, Monica [Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Mehrara, Babak J.; Disa, Joseph J.; Cordeiro, Peter G. [Department of Plastic Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Shi, Weiji; Zhang, Zhigang [Department of Biostatistics and Epidemiology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Gelblum, Daphna [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Nerbun, Claire T.; Woch, Katherine M.; Ballangrud, Ase [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); McCormick, Beryl; Powell, Simon N. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

    2014-04-01T23:59:59.000Z

    To determine if the presence of bilateral implants, in addition to other anatomic and treatment-related variables, affects coverage of the target volume and dose to the heart and lung in patients receiving postmastectomy radiation therapy (PMRT). A total of 197 consecutive women with breast cancer underwent mastectomy and immediate tissue expander (TE) placement, with or without exchange for a permanent implant (PI) before radiation therapy at our center. PMRT was delivered with 2 tangential beams + supraclavicular lymph node field (50 Gy). Patients were grouped by implant number: 51% unilateral (100) and 49% bilateral (97). The planning target volume (PTV) (defined as implant + chest wall + nodes), heart, and ipsilateral lung were contoured and the following parameters were abstracted from dose-volume histogram (DVH) data: PTV D{sub 95%} > 98%, Lung V{sub 20}Gy > 30%, and Heart V{sub 25}Gy > 5%. Univariate (UVA) and multivariate analyses (MVA) were performed to determine the association of variables with these parameters. The 2 groups were well balanced for implant type and volume, internal mammary node (IMN) treatment, and laterality. In the entire cohort, 90% had PTV D{sub 95%} > 98%, indicating excellent coverage of the chest wall. Of the patients, 27% had high lung doses (V{sub 20}Gy > 30%) and 16% had high heart doses (V{sub 25}Gy > 5%). No significant factors were associated with suboptimal PTV coverage. On MVA, IMN treatment was found to be highly associated with high lung and heart doses (both p < 0.0001), but implant number was not (p = 0.54). In patients with bilateral implants, IMN treatment was the only predictor of dose to the contralateral implant (p = 0.001). In conclusion, bilateral implants do not compromise coverage of the target volume or increase lung and heart dose in patients receiving PMRT. The most important predictor of high lung and heart doses in patients with implant-based reconstruction, whether unilateral or bilateral, is treatment of the IMNs. Refinement of radiation techniques in reconstructed patients who require comprehensive nodal irradiation is warranted.

  10. Neutron capture therapy with deep tissue penetration using capillary neutron focusing

    DOE Patents [OSTI]

    Peurrung, Anthony J. (Richland, WA)

    1997-01-01T23:59:59.000Z

    An improved method for delivering thermal neutrons to a subsurface cancer or tumor which has been first doped with a dopant having a high cross section for neutron capture. The improvement is the use of a guide tube in cooperation with a capillary neutron focusing apparatus, or neutron focusing lens, for directing neutrons to the tumor, and thereby avoiding damage to surrounding tissue.

  11. Bubble masks for time-encoded imaging of fast neutrons.

    SciTech Connect (OSTI)

    Brubaker, Erik; Brennan, James S.; Marleau, Peter; Nowack, Aaron B.; Steele, John; Sweany, Melinda; Throckmorton, Daniel J.

    2013-09-01T23:59:59.000Z

    Time-encoded imaging is an approach to directional radiation detection that is being developed at SNL with a focus on fast neutron directional detection. In this technique, a time modulation of a detected neutron signal is induced-typically, a moving mask that attenuates neutrons with a time structure that depends on the source position. An important challenge in time-encoded imaging is to develop high-resolution two-dimensional imaging capabilities; building a mechanically moving high-resolution mask presents challenges both theoretical and technical. We have investigated an alternative to mechanical masks that replaces the solid mask with a liquid such as mineral oil. Instead of fixed blocks of solid material that move in pre-defined patterns, the oil is contained in tubing structures, and carefully introduced air gaps-bubbles-propagate through the tubing, generating moving patterns of oil mask elements and air apertures. Compared to current moving-mask techniques, the bubble mask is simple, since mechanical motion is replaced by gravity-driven bubble propagation; it is flexible, since arbitrary bubble patterns can be generated by a software-controlled valve actuator; and it is potentially high performance, since the tubing and bubble size can be tuned for high-resolution imaging requirements. We have built and tested various single-tube mask elements, and will present results on bubble introduction and propagation as a function of tubing size and cross-sectional shape; real-time bubble position tracking; neutron source imaging tests; and reconstruction techniques demonstrated on simple test data as well as a simulated full detector system.

  12. Neutron Beta-Decay Jeff Martin

    E-Print Network [OSTI]

    Martin, Jeff

    : ­ superthermal sources for UCN, SNS's for CN #12;Example Experiment: The most precise measurements of neutron

  13. Boron nitride solid state neutron detector

    DOE Patents [OSTI]

    Doty, F. Patrick

    2004-04-27T23:59:59.000Z

    The present invention describes an apparatus useful for detecting neutrons, and particularly for detecting thermal neutrons, while remaining insensitive to gamma radiation. Neutrons are detected by direct measurement of current pulses produced by an interaction of the neutrons with hexagonal pyrolytic boron nitride.

  14. Nuclear Physics meets Medicine and Biology: Boron Neutron Capture Therapy

    E-Print Network [OSTI]

    F. Ballarini, F; S. Bortolussi, S; P. Bruschi, P; A.M. Clerici, A M; A. De Bari, A; P. Dionigi, P; C. Ferrari, C; M.A. Gadan, M A; N. Protti, N; S. Stella, S; C. Zonta, C; A. Zonta, A; S. Altieri, S

    2010-01-01T23:59:59.000Z

    BNCT is a tumour treatment based on thermal-neutron irradiation of tissues enriched with 10B, which according to the 10B(n, )7Li reaction produces particles with high Linear Energy Transfer and short range. Since this treatment can deliver a therapeutic tumour dose sparing normal tissues, BNCT represents an alternative for diffuse tumours and metastases, which show poor response to surgery and photontherapy. In 2001 and 2003, in Pavia BNCT was applied to an isolated liver, which was infused with boron, explanted, irradiated and re-implanted. A new project was then initiated for lung tumours, developing a protocol for Boron concentration measurements and performing organ-dose Monte Carlo calculations; in parallel, radiobiology studies are ongoing to characterize the BNCT effects down to cellular level. After a brief introduction, herein we will present the main activities ongoing in Pavia including the radiobiological ones, which are under investigation not only experimentally but also theoretically, basing on...

  15. Fast Neutron Damage Studies on NdFeB Materials

    E-Print Network [OSTI]

    Spencer, James; Baldwin, A; Boussoufi, Moe; Pellet, David; Volk, James T; Wolf, Zachary

    2005-01-01T23:59:59.000Z

    Many materials and electronics need to be tested for the radiation environment expected at linear colliders (LC) where the accelerator and detectors will be subjected to large fluences of hadrons, leptons and gammas over the life of the facility. Although the linacs will be superconducting, there are still many potential uses for NdFeB in the damping rings, injection and extraction lines and final focus. Our understanding of the radiation damage situation for rare earth permanent magnet materials was presented at PAC2003 and our first measurements of fast neutron, stepped doses at the UC Davis McClellan Nuclear Reactor Center (UCD MNRC) were presented at EPAC2004 where the damage appeared proportional to the distances between the effective operating points and Hc. Here we have extended those doses and included more commercial samples together with the induced radioactivities associated with their respective dopants. Hall probe data for the external induction distributions are compared with vector magnetizatio...

  16. Experimental results of neutron fluence outside an iron shield in the forward direction

    SciTech Connect (OSTI)

    Torres, M.M.C. [Argonne National Lab., IL (United States); Elwyn, A.J. [Fermi National Accelerator Lab., Batavia, IL (United States); Fein, D.; James, E.; Johns, K. [Arizona Univ., Tucson, AZ (United States); Davis, W. [Ball State Univ., Muncie, IN (United States); Ciampa, D.P. [Minnesota Univ., Minneapolis, MN (United States); Mierkiewicz, E. [Northern Illinois Univ., De Kalb, IL (United States)

    1996-09-01T23:59:59.000Z

    Analyses of both lateral shielding measurements and Monte Carlo calculations for beam stop geometry for incident hadrons at energies between 10 GeV and 10 TeV suggests that the dose equivalent can be represented by the expression H = H{sub 0}(E)e{sup -r/{lambda}}/r{sup 2} where H, is the source term, r is the radial distance to the point of interest in the shield, and {lambda} is the effective interaction length, or absorption mean free path. However, unlike the lateral shielding case, there is no similarly simple analytical expression that can be used to describe the on-axis longitudinal cascade development. In this study the results from the measurement in the forward direction of neutron fluence spectra (and the derived quantity dose equivalent) for 25 to 150 GeV pions incident on an iron beam stop as a function of thickness of iron are presented. The observed dependence of both fluence and dose equivalent on shield thickness and hadron energy was then quantified in terms of an expression in which a build up factor as well as an attenuation term was included. On the basis of this analysis the conversion factor from fluence to dose equivalent was also determined for these forward going neutrons. This work represents the first systematic study at an high energy accelerator of the depth dependence of neutron fluence in longitudinal shielding.

  17. Performance of a Clad Tungsten Rod Spallation Neutron Source Target

    SciTech Connect (OSTI)

    Sommer, Walter F. [Los Alamos National Laboratory (United States); Maloy, Stuart A. [Los Alamos National Laboratory (United States); Louthan, McIntyre R. [Savannah River National Laboratory (United States); Willcutt, Gordon J. [Los Alamos National Laboratory (United States); Ferguson, Phillip D. [Oak Ridge National Laboratory (United States); James, Michael R. [Los Alamos National Laboratory (United States)

    2005-09-15T23:59:59.000Z

    Tungsten rods, slip-clad with Type 304L stainless steel, performed successfully as a spallation neutron source target operating to a peak fluence of {approx}4 x 10{sup 21} p/cm{sup 2}. The target was used as a neutron source during the Accelerator Production of Tritium (APT) materials irradiation program at the Los Alamos Neutron Science Center. Tungsten rods of 2.642-mm diameter were slip-fit in Type 304L stainless steel tubes that had an inner diameter of 2.667 mm. The radial gap was filled with helium at atmospheric pressure and room temperature. Los Alamos High Energy Transport (LAHET) calculations suggest a time-averaged peak power deposition in the W of 2.25 kW/cm{sup 3}. Thermal-hydraulic calculations indicate that the peak centerline W temperature reached 271 deg. C. The LAHET calculations were also used to predict neutron and proton fluxes and spectra for the complex geometry used in the irradiation program. Activation foil sets distributed throughout the experiment were used to determine target neutronics performance as a comparison to the LAHET calculations. Examination of the irradiated target assemblies revealed no significant surface degradation or corrosion on either the Type 304L or the W surfaces. However, it was clear that the irradiation changed material properties because post-proton-irradiation measurements on Type 304L test samples from the APT program demonstrated increases in the yield strength and decreases in the ductility and fracture toughness with increasing dose, and the wrought W rod samples became brittle. Fortunately, the slip-clad target design subjects the materials to very low stress.

  18. The Magnetism of Neutron States

    E-Print Network [OSTI]

    B. G. Sidharth

    2003-10-01T23:59:59.000Z

    The recent measurement by Bignami and co-workers of the magnetic field of a neutron star for the first time gives a value that differs by about two orders of magnitude from the expected value. The speculation has been that the nuclear matter in the neutron stars exhibits some exotic behaviour. In this note we argue that this exotic behaviour is an anomalous statistics obeyed by the neutrons, and moreover these considerations lead to a value of the magnetic field that agrees with the observation. The same considerations also correctly give the magnetic fields of the earth and Jupiter.

  19. Scattered neutron tomography based on a neutron transport problem 

    E-Print Network [OSTI]

    Scipolo, Vittorio

    2005-11-01T23:59:59.000Z

    scattering objects because it does not adequately account for the scattering component of the neutron beam intensity exiting the sample. We proposed a new method of computed tomography which employs an inverse problem analysis of both the transmitted...

  20. Scattered neutron tomography based on a neutron transport problem

    E-Print Network [OSTI]

    Scipolo, Vittorio

    2005-11-01T23:59:59.000Z

    scattering objects because it does not adequately account for the scattering component of the neutron beam intensity exiting the sample. We proposed a new method of computed tomography which employs an inverse problem analysis of both the transmitted...

  1. Modulating the Neutron Flux from a Mirror Neutron Source

    SciTech Connect (OSTI)

    Ryutov, D D

    2011-09-01T23:59:59.000Z

    A 14-MeV neutron source based on a Gas-Dynamic Trap will provide a high flux of 14 MeV neutrons for fusion materials and sub-component testing. In addition to its main goal, the source has potential applications in condensed matter physics and biophysics. In this report, the author considers adding one more capability to the GDT-based neutron source, the modulation of the neutron flux with a desired frequency. The modulation may be an enabling tool for the assessment of the role of non-steady-state effects in fusion devices as well as for high-precision, low-signal basic science experiments favoring the use of the synchronous detection technique. A conclusion is drawn that modulation frequency of up to 1 kHz and modulation amplitude of a few percent is achievable. Limitations on the amplitude of modulations at higher frequencies are discussed.

  2. Jet Reconstruction in Heavy Ion Collisions

    E-Print Network [OSTI]

    Sevil Salur

    2009-05-12T23:59:59.000Z

    Measurements of strong suppression of inclusive hadron distributions and di-hadron correlations at high $p_{T}$, while providing evidence for partonic energy loss, also suffer from geometric biases due to the competition of energy loss and fragmentation. The measurements of fully reconstructed jets is expected to lack these biases as the energy flow is measured independently of the fragmentation details. In this article, we review the recent results from the heavy ion collisions collected by the STAR experiment at RHIC on direct jet reconstruction utilizing the modern sequential recombination and cone jet reconstruction algorithms together with their background subtraction techniques. In order to assess the jet reconstruction biases a comparison with the jet cross section measurement in $\\sqrt{s}=200$ GeV p+p collisions scaled by the number of binary nucleon-nucleon collisions to account for nuclear geometric effects is performed. Comparison of the inclusive jet cross section obtained in central Au+Au events with that in $p+p$ collisions, published previously by STAR, suggests that unbiased jet reconstruction in the complex heavy ion environment indeed may be possible.

  3. Tolerance doses for treatment planning

    SciTech Connect (OSTI)

    Lyman, J.T.

    1985-10-01T23:59:59.000Z

    Data for the tolerance of normal tissues or organs to (low-LET) radiation has been compiled from a number of sources which are referenced at the end of this document. This tolerance dose data are ostensibly for uniform irradiation of all or part of an organ, and are for either 5% (TD/sub 5/) or 50% (TD/sub 50/) complication probability. The ''size'' of the irradiated organ is variously stated in terms of the absolute volume or the fraction of the organ volume irradiated, or the area or the length of the treatment field. The accuracy of these data is questionable. Much of the data represents doses that one or several experienced therapists have estimated could be safely given rather than quantitative analyses of clinical observations. Because these data have been obtained from multiple sources with possible different criteria for the definition of a complication, there are sometimes different values for what is apparently the same endpoint. The data from some sources shows a tendancy to be quantized in 5 Gy increments. This reflects the size of possible round off errors. It is believed that all these data have been accumulated without the benefit of 3-D dose distributions and therefore the estimates of the size of the volume and/or the uniformity of the irradiation may be less accurate than is now possible. 19 refs., 4 figs.

  4. Isoscaling of fragments with Z=1-17 from reconstructed quasiprojectiles

    SciTech Connect (OSTI)

    Wuenschel, S.; Kohley, Z.; May, L. W.; Soisson, S. N.; Stein, B. C.; Yennello, S. J. [Chemistry Department, Texas A and M University, College Station, Texas 77843 (United States); Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States); Dienhoffer, R. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States); Department of Physics, State University of New York at Oswego, New York 13126 (United States); Souliotis, G. A.; Galanopoulos, S.; Hagel, K.; Shetty, D. V.; Huseman, K. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States); Caraley, A. L. [Department of Physics, State University of New York at Oswego, New York 13126 (United States)

    2009-06-15T23:59:59.000Z

    In heavy-ion collisions, isoscaling provides a method for studying the evolution of nuclear symmetry energy as a function of excitation energy. One challenge in using isoscaling is to accurately determine the neutron-to-proton ratio (N/Z) of the fragmenting source. Isoscaling results are presented for the reactions of {sup 86,78}Kr+{sup 64,58}Ni at 35 MeV/nucleon taken on the NIMROD-ISiS array at Texas A and M University. The N/Z of the source was calculated from the isotopically identified fragments and experimentally measured neutrons emitted from reconstructed quasiprojectiles. These data exhibit isoscaling for elements with Z=1-17 over a broad range of isotopes. The isoscaling parameter {alpha} is shown to increase with increasing difference in the neutron composition ({delta}) of the compared sources. For a selected {delta}, the ratio {alpha}/{delta} is also shown to decrease with increasing excitation energy. This may reflect a corresponding decrease in the nuclear symmetry energy.

  5. A METHODOLOGY FOR DETERMINING THE DOSE RATE FOR BOUNDING MASS LIMITS IN A 9977 PACKAGING

    SciTech Connect (OSTI)

    Abramczyk, G.; Bellamy, S.; Nathan, S.; Loftin, B.

    2012-05-24T23:59:59.000Z

    The Small Gram Quantity (SGQ) concept is based on the understanding that the hazards associated with the shipment of a radioactive material are directly proportional to its mass. This study describes a methodology that estimates the acceptable masses for several neutron and gamma emitting isotopes that can be shipped in a 9977 Package compliant with the Title 10 of the Code of Federal Regulations, Part 71 (10CFR71) external radiation level limits. 10CFR71.33 states that a shipping application identifies the radioactive and fissile materials at their maximum quantity and provides an evaluation demonstrating compliance with the external radiation standards. Since rather small amounts of some isotopes emit sufficiently strong radiation to produce a large external dose rate, quantifying of the dose rate for a proposed content is a challenging issue for the SGQ approach. It is essential to quantify external radiation levels from several common gamma and neutron sources that can be safely placed in a specific packaging, to ensure compliance with federal regulations. A methodology was established for determining the dose rate for bounding mass limits for a set of isotopes in the Model 9977 Shipping Package. Calculations were performed to estimate external radiation levels using the MCNP radiation transport code to develop a set of response multipliers (Green's functions) for 'dose per source particle' for each neutron and photon spectral group. The source spectrum from one gram of each isotope was folded with the response multipliers to generate the dose rate per gram of each isotope in the 9977 shipping package and its associated shielded containers. The maximum amount of a single isotope that could be shipped within the regulatory limits for dose rate at the surface was determined. For a package containing a mixture of isotopes, the acceptability for shipment can be determined by a sum of fractions approach. Furthermore, the results of this analysis can be easily extended to additional radioisotopes by simply evaluating the neutron and/or photon spectra of those isotopes and folding the spectral data with the Green's functions provided.

  6. The effects of gantry tilt on breast dose and image noise in cardiac CT

    SciTech Connect (OSTI)

    Hoppe, Michael E.; Gandhi, Diksha; Schmidt, Taly Gilat [Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin 53233 (United States)] [Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin 53233 (United States); Stevens, Grant M. [GE Healthcare, Waukesha, Wisconsin 53188 (United States)] [GE Healthcare, Waukesha, Wisconsin 53188 (United States); Foley, W. Dennis [Department of Radiology, Medical College of Wisconsin, Froedtert Memorial Lutheran Hospital, Milwaukee, Wisconsin 53226 (United States)] [Department of Radiology, Medical College of Wisconsin, Froedtert Memorial Lutheran Hospital, Milwaukee, Wisconsin 53226 (United States)

    2013-12-15T23:59:59.000Z

    Purpose: This study investigated the effects of tilted-gantry acquisition on image noise and glandular breast dose in females during cardiac computed tomography (CT) scans. Reducing the dose to glandular breast tissue is important due to its high radiosensitivity and limited diagnostic significance in cardiac CT scans.Methods: Tilted-gantry acquisition was investigated through computer simulations and experimental measurements. Upon IRB approval, eight voxelized phantoms were constructed from previously acquired cardiac CT datasets. Monte Carlo simulations quantified the dose deposited in glandular breast tissue over a range of tilt angles. The effects of tilted-gantry acquisition on breast dose were measured on a clinical CT scanner (CT750HD, GE Healthcare) using an anthropomorphic phantom with MOSFET dosimeters in the breast regions. In both simulations and experiments, scans were performed at gantry tilt angles of 0°–30°, in 5° increments. The percent change in breast dose was calculated relative to the nontilted scan for all tilt angles. The percent change in noise standard deviation due to gantry tilt was calculated in all reconstructed simulated and experimental images.Results: Tilting the gantry reduced the breast dose in all simulated and experimental phantoms, with generally greater dose reduction at increased gantry tilts. For example, at 30° gantry tilt, the dosimeters located in the superior, middle, and inferior breast regions measured dose reductions of 74%, 61%, and 9%, respectively. The simulations estimated 0%–30% total breast dose reduction across the eight phantoms and range of tilt angles. However, tilted-gantry acquisition also increased the noise standard deviation in the simulated phantoms by 2%–50% due to increased pathlength through the iodine-filled heart. The experimental phantom, which did not contain iodine in the blood, demonstrated decreased breast dose and decreased noise at all gantry tilt angles.Conclusions: Tilting the gantry reduced the dose to the breast, while also increasing noise standard deviation. Overall, the noise increase outweighed the dose reduction for the eight voxelized phantoms, suggesting that tilted gantry acquisition may not be beneficial for reducing breast dose while maintaining image quality.

  7. The nuclear physics of neutron stars

    SciTech Connect (OSTI)

    Piekarewicz, J. [Department of Physics, Florida State University, Tallahassee, FL 32306-4350 (United States)

    2014-05-09T23:59:59.000Z

    We explore the unique and fascinating structure of neutron stars. Although neutron stars are of interest in many areas of Physics, our aim is to provide an intellectual bridge between Nuclear Physics and Astrophysics. We argue against the naive perception of a neutron star as a uniform assembly of neutrons packed to enormous densities. Rather, by focusing on the many exotic phases that are speculated to exist in a neutron star, we show how the reality is different and far more interesting.

  8. Robust statistical reconstruction for charged particle tomography

    DOE Patents [OSTI]

    2013-10-08T23:59:59.000Z

    Systems and methods for charged particle detection including statistical reconstruction of object volume scattering density profiles from charged particle tomographic data to determine the probability distribution of charged particle scattering using a statistical multiple scattering model and determine a substantially maximum likelihood estimate of object volume scattering density using expectation maximization (ML/EM) algorithm to reconstruct the object volume scattering density. The presence of and/or type of object occupying the volume of interest can be identified from the reconstructed volume scattering density profile. The charged particle tomographic data can be cosmic ray muon tomographic data from a muon tracker for scanning packages, containers, vehicles or cargo. The method can be implemented using a computer program which is executable on a computer.

  9. Los Alamos Neutron Science Center The Los Alamos Neutron Science Center (LANSCE) is a

    E-Print Network [OSTI]

    a target of tungsten metal, neutrons are produced. These neutrons and protons are used to investigate, high explosives used to initiate weapons detonations, and radioisotope production for medical the Isotope Production Facility, Lujan Center, Proton Radiography Facility, Ultracold Neutrons Facility

  10. Distribution of neutron resonance widths

    E-Print Network [OSTI]

    Hans A. Weidenmueller

    2011-10-28T23:59:59.000Z

    Recent data on neutron resonance widths indicate disagreement with the Porter-Thomas distribution (PTD). I discuss the theoretical arguments for the PTD, possible theoretical modifications, and I summarize the experimantal evidence.

  11. Coherent control of neutron interferometry

    E-Print Network [OSTI]

    Pushin, Dmitry A

    2007-01-01T23:59:59.000Z

    In this thesis, several novel techniques are proposed and demonstrated for measuring the coherent properties of materials and testing aspects of quantum information processing using a single crystal neutron interferometer. ...

  12. Materials for spallation neutron sources

    SciTech Connect (OSTI)

    Sommer, W.F.; Daemen, L.L. [comps.

    1996-03-01T23:59:59.000Z

    The Workshop on Materials for Spallation Neutron Sources at the Los Alamos Neutron Science Center, February 6 to 10, 1995, gathered scientists from Department of Energy national laboratories, other federal institutions, universities, and industry to discuss areas in which work is needed, successful designs and use of materials, and opportunities for further studies. During the first day of the workshop, speakers presented overviews of current spallation neutron sources. During the next 3 days, seven panels allowed speakers to present information on a variety of topics ranging from experimental and theoretical considerations on radiation damage to materials safety issues. An attempt was made to identify specific problems that require attention within the context of spallation neutron sources. This proceedings is a collection of summaries from the overview sessions and the panel presentations.

  13. Ion chamber based neutron detectors

    DOE Patents [OSTI]

    Derzon, Mark S; Galambos, Paul C; Renzi, Ronald F

    2014-12-16T23:59:59.000Z

    A neutron detector with monolithically integrated readout circuitry, including: a bonded semiconductor die; an ion chamber formed in the bonded semiconductor die; a first electrode and a second electrode formed in the ion chamber; a neutron absorbing material filling the ion chamber; and the readout circuitry which is electrically coupled to the first and second electrodes. The bonded semiconductor die includes an etched semiconductor substrate bonded to an active semiconductor substrate. The readout circuitry is formed in a portion of the active semiconductor substrate. The ion chamber has a substantially planar first surface on which the first electrode is formed and a substantially planar second surface, parallel to the first surface, on which the second electrode is formed. The distance between the first electrode and the second electrode may be equal to or less than the 50% attenuation length for neutrons in the neutron absorbing material filling the ion chamber.

  14. Formulation and solution of the delayed gamma dose rate problem using the concept of effective delayed gamma production cross section

    SciTech Connect (OSTI)

    Liew, S.L.; Ku, L.P.

    1989-06-01T23:59:59.000Z

    With appropriate approximations, the delayed gamma dose rate problem can be formulated in terms of the effective delayed gamma production cross section. The coupled neutron-delayed-gamma transport equations then take the same form as the coupled neutron-prompt-gamma transport equations and they can, therefore, be solved directly in the same manner. This eliminates the need for the tedious and error prone flux coupling step in conventional calculations. Mathematical formulation and solution algorithms are derived. The advantages of this method are illustrated by an example of its application in the solution of a practical design problem. 62 refs., 10 figs., 1 tab.

  15. acp safeguards neutron: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    29 Supercool Neutrons (Ultracold Neutrons) Physics Websites Summary: . Korobkina, NCSU Neutron scattering is a valuable tool to study the structure of materials. Because Helium...

  16. Neutron Scattering: Condensed Matter and Magnetic Science, MPA...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Neutron Scattering Neutron Scattering Capability description: Neutron scattering is a powerful probe of structure and collective modes of condensed matter. We are focused on direct...

  17. Application of neutron computed tomography in the geosciences

    E-Print Network [OSTI]

    Wilding, M.; Shields, K.; Lesher, C. E.

    2005-01-01T23:59:59.000Z

    of neutron computed tomography in the geosciences Martinthat applies neutron computed tomography (CT) to geologicalthe use of neutron computed tomography (CT) in the analy-

  18. 11th LANSCE School on Neutron Scattering | About the School

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    students calculate results About the LANSCE School on Neutron Scattering The annual Los Alamos Neutron Science Center (LANSCE) School on Neutron Scattering is 9- to 10-day school...

  19. Multiple anatomy optimization of accumulated dose

    SciTech Connect (OSTI)

    Watkins, W. Tyler, E-mail: watkinswt@virginia.edu; Siebers, Jeffrey V. [Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia 22908 and Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States); Moore, Joseph A. [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland 21231 and Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States); Gordon, James [Henry Ford Health System, Detroit, Michigan 48202 and Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States); Hugo, Geoffrey D. [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States)

    2014-11-01T23:59:59.000Z

    Purpose: To investigate the potential advantages of multiple anatomy optimization (MAO) for lung cancer radiation therapy compared to the internal target volume (ITV) approach. Methods: MAO aims to optimize a single fluence to be delivered under free-breathing conditions such that the accumulated dose meets the plan objectives, where accumulated dose is defined as the sum of deformably mapped doses computed on each phase of a single four dimensional computed tomography (4DCT) dataset. Phantom and patient simulation studies were carried out to investigate potential advantages of MAO compared to ITV planning. Through simulated delivery of the ITV- and MAO-plans, target dose variations were also investigated. Results: By optimizing the accumulated dose, MAO shows the potential to ensure dose to the moving target meets plan objectives while simultaneously reducing dose to organs at risk (OARs) compared with ITV planning. While consistently superior to the ITV approach, MAO resulted in equivalent OAR dosimetry at planning objective dose levels to within 2% volume in 14/30 plans and to within 3% volume in 19/30 plans for each lung V20, esophagus V25, and heart V30. Despite large variations in per-fraction respiratory phase weights in simulated deliveries at high dose rates (e.g., treating 4/10 phases during single fraction beams) the cumulative clinical target volume (CTV) dose after 30 fractions and per-fraction dose were constant independent of planning technique. In one case considered, however, per-phase CTV dose varied from 74% to 117% of prescription implying the level of ITV-dose heterogeneity may not be appropriate with conventional, free-breathing delivery. Conclusions: MAO incorporates 4DCT information in an optimized dose distribution and can achieve a superior plan in terms of accumulated dose to the moving target and OAR sparing compared to ITV-plans. An appropriate level of dose heterogeneity in MAO plans must be further investigated.

  20. Neutron detectors comprising boron powder

    DOE Patents [OSTI]

    Wang, Zhehui; Morris, Christopher; Bacon, Jeffrey Darnell; Makela, Mark F; Spaulding, Randy Jay

    2013-05-21T23:59:59.000Z

    High-efficiency neutron detector substrate assemblies comprising a first conductive substrate, wherein a first side of the substrate is in direct contact with a first layer of a powder material comprising .sup.10boron, .sup.10boron carbide or combinations thereof, and wherein a conductive material is in proximity to the first layer of powder material; and processes of making said neutron detector substrate assemblies.

  1. Alternative Neutron Detection Testing Summary

    SciTech Connect (OSTI)

    Kouzes, Richard T.; Ely, James H.; Erikson, Luke E.; Kernan, Warnick J.; Lintereur, Azaree T.; Siciliano, Edward R.; Stromswold, David C.; Woodring, Mitchell L.

    2010-04-08T23:59:59.000Z

    Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. Most currently deployed radiation portal monitors (RPMs) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large area neutron detector. This type of neutron detector is used in the TSA and other RPMs installed in international locations and in the Ludlum and Science Applications International Corporation RPMs deployed primarily for domestic applications. There is a declining supply of 3He in the world and, thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Four technologies have been identified as being currently commercially available, potential alternative neutron detectors to replace the use of 3He in RPMs. These technologies are: 1) Boron trifluoride-filled proportional counters, 2) Boron-lined proportional counters, 3) Lithium-loaded glass fibers, and 4) Coated wavelength-shifting plastic fibers. Reported here is a summary of the testing carried out at Pacific Northwest National Laboratory on these technologies to date, as well as measurements on 3He tubes at various pressures. Details on these measurements are available in the referenced reports. Sponsors of these tests include the Department of Energy (DOE), Department of Homeland Security (DHS), and the Department of Defense (DoD), as well as internal Pacific Northwest National Laboratory funds.

  2. Lagrangian reconstruction of cosmic velocity fields

    E-Print Network [OSTI]

    G. Lavaux

    2008-01-28T23:59:59.000Z

    We discuss a Lagrangian reconstruction method of the velocity field from galaxy redshift catalog that takes its root in the Euler equation. This results in a ``functional'' of the velocity field which must be minimized. This is helped by an algorithm solving the minimization of cost-flow problems. The results obtained by applying this method to cosmological problems are shown and boundary effects happening in real observational cases are then discussed. Finally, a statistical model of the errors made by the reconstruction method is proposed.

  3. A method to estimate the effect of deformable image registration uncertainties on daily dose mapping

    SciTech Connect (OSTI)

    Murphy, Martin J.; Salguero, Francisco J.; Siebers, Jeffrey V.; Staub, David; Vaman, Constantin [Department of Radiation Oncology, Virginia Commonwealth University, Richmond Virginia 23298 (United States)

    2012-02-15T23:59:59.000Z

    Purpose: To develop a statistical sampling procedure for spatially-correlated uncertainties in deformable image registration and then use it to demonstrate their effect on daily dose mapping. Methods: Sequential daily CT studies are acquired to map anatomical variations prior to fractionated external beam radiotherapy. The CTs are deformably registered to the planning CT to obtain displacement vector fields (DVFs). The DVFs are used to accumulate the dose delivered each day onto the planning CT. Each DVF has spatially-correlated uncertainties associated with it. Principal components analysis (PCA) is applied to measured DVF error maps to produce decorrelated principal component modes of the errors. The modes are sampled independently and reconstructed to produce synthetic registration error maps. The synthetic error maps are convolved with dose mapped via deformable registration to model the resulting uncertainty in the dose mapping. The results are compared to the dose mapping uncertainty that would result from uncorrelated DVF errors that vary randomly from voxel to voxel. Results: The error sampling method is shown to produce synthetic DVF error maps that are statistically indistinguishable from the observed error maps. Spatially-correlated DVF uncertainties modeled by our procedure produce patterns of dose mapping error that are different from that due to randomly distributed uncertainties. Conclusions: Deformable image registration uncertainties have complex spatial distributions. The authors have developed and tested a method to decorrelate the spatial uncertainties and make statistical samples of highly correlated error maps. The sample error maps can be used to investigate the effect of DVF uncertainties on daily dose mapping via deformable image registration. An initial demonstration of this methodology shows that dose mapping uncertainties can be sensitive to spatial patterns in the DVF uncertainties.

  4. Displacement damage effects on CMOS APS image sensors induced by neutron irradiation from a nuclear reactor

    SciTech Connect (OSTI)

    Wang, Zujun, E-mail: wangzujun@nint.ac.cn; Huang, Shaoyan; Liu, Minbo; Xiao, Zhigang; He, Baoping; Yao, Zhibin; Sheng, Jiangkun [State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi'an, Shaanxi 710024 China (China)

    2014-07-15T23:59:59.000Z

    The experiments of displacement damage effects on CMOS APS image sensors induced by neutron irradiation from a nuclear reactor are presented. The CMOS APS image sensors are manufactured in the standard 0.35 ?m CMOS technology. The flux of neutron beams was about 1.33 × 10{sup 8} n/cm{sup 2}s. The three samples were exposed by 1 MeV neutron equivalent-fluence of 1 × 10{sup 11}, 5 × 10{sup 11}, and 1 × 10{sup 12} n/cm{sup 2}, respectively. The mean dark signal (K{sub D}), dark signal spike, dark signal non-uniformity (DSNU), noise (V{sub N}), saturation output signal voltage (V{sub S}), and dynamic range (DR) versus neutron fluence are investigated. The degradation mechanisms of CMOS APS image sensors are analyzed. The mean dark signal increase due to neutron displacement damage appears to be proportional to displacement damage dose. The dark images from CMOS APS image sensors irradiated by neutrons are presented to investigate the generation of dark signal spike.

  5. ORISE: Dose modeling and assessments

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated CodesTransparencyDOE ProjectCrisis and Risk CommunicationOakDose modeling

  6. High-dose MVCT image guidance for stereotactic body radiation therapy

    SciTech Connect (OSTI)

    Westerly, David C.; Schefter, Tracey E.; Kavanagh, Brian D.; Chao, Edward; Lucas, Dan; Flynn, Ryan T.; Miften, Moyed [Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado 80045 (United States); Accuray Inc., Madison, Wisconsin 53717 (United States); Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, Iowa 52242 (United States); Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado 80045 (United States)

    2012-08-15T23:59:59.000Z

    Purpose: Stereotactic body radiation therapy (SBRT) is a potent treatment for early stage primary and limited metastatic disease. Accurate tumor localization is essential to administer SBRT safely and effectively. Tomotherapy combines helical IMRT with onboard megavoltage CT (MVCT) imaging and is well suited for SBRT; however, MVCT results in reduced soft tissue contrast and increased image noise compared with kilovoltage CT. The goal of this work was to investigate the use of increased imaging doses on a clinical tomotherapy machine to improve image quality for SBRT image guidance. Methods: Two nonstandard, high-dose imaging modes were created on a tomotherapy machine by increasing the linear accelerator (LINAC) pulse rate from the nominal setting of 80 Hz, to 160 Hz and 300 Hz, respectively. Weighted CT dose indexes (wCTDIs) were measured for the standard, medium, and high-dose modes in a 30 cm solid water phantom using a calibrated A1SL ion chamber. Image quality was assessed from scans of a customized image quality phantom. Metrics evaluated include: contrast-to-noise ratios (CNRs), high-contrast spatial resolution, image uniformity, and percent image noise. In addition, two patients receiving SBRT were localized using high-dose MVCT scans. Raw detector data collected after each scan were used to reconstruct standard-dose images for comparison. Results: MVCT scans acquired using a pitch of 1.0 resulted in wCTDI values of 2.2, 4.7, and 8.5 cGy for the standard, medium, and high-dose modes respectively. CNR values for both low and high-contrast materials were found to increase with the square root of dose. Axial high-contrast spatial resolution was comparable for all imaging modes at 0.5 lp/mm. Image uniformity was improved and percent noise decreased as the imaging dose increased. Similar improvements in image quality were observed in patient images, with decreases in image noise being the most notable. Conclusions: High-dose imaging modes are made possible on a clinical tomotherapy machine by increasing the LINAC pulse rate. Increasing the imaging dose results in increased CNRs; making it easier to distinguish the boundaries of low contrast objects. The imaging dose levels observed in this work are considered acceptable at our institution for SBRT treatments delivered in 3-5 fractions.

  7. Statistical Image Reconstruction Algorithms Using Paraboloidal Surrogates for PET Transmission

    E-Print Network [OSTI]

    Fessler, Jeffrey A.

    Statistical Image Reconstruction Algorithms Using Paraboloidal Surrogates for PET Transmission Reconstruction Algorithms Using Paraboloidal Surrogates for PET Transmission Scans by Hakan Erdogan Chair: Jeffrey A. Fessler Positron Emission Tomography (PET) is a diagnostic imaging tool that provides images

  8. Monte Carlo event reconstruction implemented with artificial neural networks

    E-Print Network [OSTI]

    Tolley, Emma Elizabeth

    2011-01-01T23:59:59.000Z

    I implemented event reconstruction of a Monte Carlo simulation using neural networks. The OLYMPUS Collaboration is using a Monte Carlo simulation of the OLYMPUS particle detector to evaluate systematics and reconstruct ...

  9. On reconstruction and time reversal in thermoacoustic tomography in acoustically

    E-Print Network [OSTI]

    Kuchment, Peter

    On reconstruction and time reversal in thermoacoustic tomography in acoustically homogeneous of recent approaches to the reconstruction in thermoacoustic/photoacoustic tomography: backprojection of the problem of sound speed recovery is also provided. Keywords: Tomography, thermoacoustic, wave equation. AMS

  10. The Virtual (Re)Construction of History: Some Epistemological Questions

    E-Print Network [OSTI]

    El Antably, Ahmed

    2010-01-01T23:59:59.000Z

    Antably: The Virtual (Re)Construction of History 14. DoreenMay 1, 2010 THE VIRTUAL (RE)CONSTRUCTION OF HISTORY: SOMEthe use of perspectival constructions that emulate everyday

  11. Computational confocal tomography for simultaneous reconstruction of objects, occlusions,

    E-Print Network [OSTI]

    Fainman, Yeshaiahu

    Computational confocal tomography for simultaneous reconstruction of objects, occlusions computationally intense and novel reconstruction methods that we called "compu- tational confocal tomography." The key to computed tomography is the collection of projections of the data over a range of angles

  12. Money Reconstructed: Argentina and Brazil after Hyperinflation

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Money Reconstructed: Argentina and Brazil after Hyperinflation Jérôme Sgard (Sciences Po / CERI and transferred on alternate supports--either a foreign currency (as in Argentina) or domestic indices (as empirical material and an extended analytical discussion. Keywords: Argentina, Brazil, hyperinflation

  13. A reconstruction of the tables of Thompson's

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    A reconstruction of the tables of Thompson's Logarithmetica Britannica (1952) Denis Roegel 20-21Dec2011 #12;hal-00654453,version1-21Dec2011 #12;1 Alexander John Thompson (1885­19??) Alexander John Thompson was born in 1885 in Plaistow, Essex, England. In 1920, he joined the statistical staff

  14. Reconstruction in tomography with diffracting sources

    E-Print Network [OSTI]

    Xu, Yuan

    2005-02-17T23:59:59.000Z

    Homogeneous Model . . . . . . . . . . . . . . . . . . . 22 III LIMITED-VIEW THERMOACOUSTIC TOMOGRAPHY1 . . . 24 A. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . 24 1. Analysis of Singularities in Circular Radon Trans- form and Limited-view TAT... . . . . . . . . . . . . . . 26 a. Circular Radon Transform . . . . . . . . . . . . . 26 b. TAT . . . . . . . . . . . . . . . . . . . . . . . . . 27 c. Reconstruction Methods . . . . . . . . . . . . . . 30 2. Numerical Implementation . . . . . . . . . . . . . . . 35 viii CHAPTER...

  15. Estimates of Columbia River radionuclide concentrations: Data for Phase 1 dose calculations

    SciTech Connect (OSTI)

    Richmond, M.C.; Walters, W.H.

    1991-05-01T23:59:59.000Z

    Pacific Northwest Laboratory is conducting the Hanford Environmental Dose Reconstruction Project to estimate the radiation doses people may have received from historical Hanford Site operations. Under the direction of an independent Technical Steering Panel, the project is being conducted in phases. The objective of the first phase is to assess the feasibility of the project-wide technical approach for acquiring data and developing models needed to calculate potential radiation doses. This report summarizes data that were generated for the Phase 1 dose calculations. These included monthly average concentrations of specific radionuclides in Columbia River water and sediments between Priest Rapids Dam and McNary Dam for the years 1964 to 1966. Nine key radionuclides were selected for analysis based on estimation of their contribution to dose. Concentrations of these radionuclides in the river were estimated using existing measurements and hydraulic calculations based on the simplifying assumption that dilution and decay were the primary processes controlling the fate of radionuclides released to the river. Five sub-reaches between Priest Rapids Dam and McNary Dam, corresponding to population centers and tributary confluences, were identified and monthly average radionuclide concentrations were calculated for each sub-reach. The hydraulic calculations were performed to provide radionuclide concentration estimates for time periods and geographic locations where measured data were not available. The validity of the calculation method will be evaluated in Phase 2. 12 refs., 13 figs., 49 tabs.

  16. IMPROVED MULTIPLEXED IMAGE RECONSTRUCTION PERFORMANCE THROUGH OPTICAL SYSTEM DIVERSITY DESIGN

    E-Print Network [OSTI]

    Rajan, Dinesh

    , Dallas, Texas, 75275 rajand@engr.smu.edu, mpc@engr.smu.edu ABSTRACT Multiplexed image reconstruction

  17. A. Cormack's last inversion formula and a FBP reconstruction

    E-Print Network [OSTI]

    Victor Palamodov

    2014-07-31T23:59:59.000Z

    A reconstruction of a function from integrals over the family of confocal paraboloids is given by a FBP formula.

  18. anthropometrically derived dosing: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Jonathan 102 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  19. additional dose assessment: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Jonathan 139 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  20. absorbed gamma dose: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Index 1 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  1. atoll dose assessment: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Jonathan 89 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  2. absorbed dose profiles: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Index 1 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  3. administer therapeutic dose: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Jonathan 133 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  4. astronaut absorbed dose: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Index 1 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  5. absorbed dose kerma: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Index 1 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  6. assess lung dose: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Morgan 68 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  7. avaliacao da dose: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Jonathan 31 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  8. absorbed dose estimates: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    NTS tests 3 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  9. absorbed doses: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Index 1 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  10. absorbed doses received: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Index 1 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  11. absorbed radiation dose: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    10 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  12. average absorbed doses: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Index 1 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  13. assessing organ doses: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Jonathan 140 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  14. absorbed dose optimization: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Index 1 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  15. afterloading high dose: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    71 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  16. absorbed dose estimation: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    NTS tests 3 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  17. absorbed glandular dose: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Index 1 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  18. absorbed dose metrology: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Index 1 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  19. absorbed dose onboard: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Index 1 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  20. affecting dose distributions: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Index 141 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  1. absorbed doses profiles: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Index 1 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  2. absorbed dose appears: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Index 1 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  3. absorbed dose computations: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Index 1 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  4. absorbed dose 3d: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Index 1 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  5. acenocoumarol dose based: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Jonathan 48 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  6. absorbed doses onboard: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Index 1 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  7. absorbed dose evaluation: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Index 1 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  8. System and apparatus for neutron radiography

    SciTech Connect (OSTI)

    Whittemore, W.L.

    1991-07-02T23:59:59.000Z

    This patent describes a neutron radiography apparatus. It comprises an imaging plane; a neutron moderator having a cavity defining a convergent collimator, the cavity having a base and converging walls of neutron moderating material terminating at an aperture; a divergent collimator coaxially joined to the cavity at the aperture, the divergent collimator having diverging walls of radiation- absorbing material extending from the aperture to an expanded distal opening for irradiating the imaging plane; sources of neutrons disposed symmetrically about the base of the cavity; a neutron moderating material disposed for maximum neutron thermalization between the sources and the base of the cavity; and means for substantially shielding the plane from electromagnetic energy.

  9. Chemico-Biological Interactions 166 (2007) 264276 Chemical process-based reconstruction of exposures for an

    E-Print Network [OSTI]

    Illinois at Chicago, University of

    2007-01-01T23:59:59.000Z

    . Keywords: Chloroprene; Vinyl chloride; Plastics; Synthetic rubber; Exposure reconstruction; Occupational

  10. atomic bomb neutrons: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the neutron density. Finally, in the case of neutron stars, where again the neutron-neutron scattering length is negative and fixed, we determine the condensate fraction as a...

  11. TURKEY'S CIVILIAN CAPACITY IN POST-CONFLICT RECONSTRUCTION

    E-Print Network [OSTI]

    Yanikoglu, Berrin

    TURKEY'S CIVILIAN CAPACITY IN POST-CONFLICT RECONSTRUCTION 1 TURKEY'S CIVILIAN CAPACITY IN POST-CONFLICT RECONSTRUCTION by Teri Murphy & Onur Sazak #12;Turkey's Civilian Capacity in post-Conflict Reconstruction By Teri-checking was indispensable for the realization of this project. #12;TURKEY'S CIVILIAN CAPACITY IN POST

  12. Statistical methods for tomographic image reconstruction Jeffrey A. Fessler

    E-Print Network [OSTI]

    Fessler, Jeffrey A.

    ) · Pittsburgh PET/CT "side information" scans reconstructed using ASPIRE 3 #12;PET Data Collection i Ray Radial 7, 2000 #12;Outline · Group/Lab · PET Imaging · Statistical image reconstruction Choices / tradeoffs Positions AngularPositions Sinogram i = 1 i = nd nd (ncrystals)2 4 #12;PET Reconstruction Problem

  13. 2013 Review of Neutron and Non-Neutron Nuclear Data

    SciTech Connect (OSTI)

    Holden, N. E. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2014-05-23T23:59:59.000Z

    The results of a review and evaluation of neutron and non-neutron nuclear data published in the scientific literature over the past three years since the ISRD-14 Symposium has been performed and the highlights are presented. Included in the data review are the status of new chemical elements, new measurements of the isotopic composition for many chemical elements and the resulting change in the atomic weight values. New half-life measurements for both short-lived and longlived nuclides, some alpha decay and double beta decay measurements for quasistable nuclides are discussed. The latest evaluation of atomic masses has been published. Data from new measurements on the very heavy (trans-meitnerium) elements are discussed and tabulated. Data on various recent neutron cross section and resonance integral measurements are discussed and tabulated.

  14. - and -delayed neutron- decay of neutron-rich copper isotopes

    SciTech Connect (OSTI)

    Korgul, A. [University of Warsaw; Rykaczewski, Krzysztof Piotr [ORNL; Winger, J. A. [Oak Ridge Associated Universities (ORAU); Ilyushkin, S. [Mississippi State University (MSU); Gross, Carl J [ORNL; Batchelder, J. C. [Oak Ridge Associated Universities (ORAU); Bingham, C. R. [University of Tennessee, Knoxville (UTK); Borzov, Ivan N [ORNL; Goodin, C. [Vanderbilt University; Grzywacz, Robert Kazimierz [ORNL; Hamilton, Joseph H [ORNL; Krolas, W. [Joint Institute for Heavy Ion Research, Oak Ridge; Liddick, S. N. [Oak Ridge Associated Universities (ORAU); Mazzocchi, C. [University of Warsaw; Nelson, C. [Vanderbilt University; Nowacki, F. [Institut Pluridisciplinaire Hubert Curien, Strasbourg, France; Padgett, Stephen [University of Tennessee, Knoxville (UTK); Piechaczek, A. [Louisiana State University; Rajabali, M. M. [University of Tennessee, Knoxville (UTK); Shapira, Dan [ORNL; Sieja, K. [Technische Universitat Darmstadt, Germany; Zganjar, E. F. [Louisiana State University

    2012-01-01T23:59:59.000Z

    The {beta}-decay properties of neutron-rich Cu isotopes produced in proton-induced fission of {sup 238}U were studied at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The data were collected using high-resolution online mass separation, reacceleration, and digital {beta}-{gamma} spectroscopy methods. An improved decay scheme of N = 49 {sup 78}Cu and the first observation of N = 50 {sup 79}Cu {beta}-delayed neutron decay followed by a gamma transition are reported. Spin and parity (5{sup -}) are deduced for {sup 78gs}Cu. The {beta}-delayed neutron branching ratios (P{sub {beta}n}) for the {sup 77}Cu and {sup 79}Cu precursors are analyzed with the help of nuclear structure models.

  15. The image quality of ion computed tomography at clinical imaging dose levels

    SciTech Connect (OSTI)

    Hansen, David C., E-mail: dch@oncology.au.dk [Department of Experimental Clinical Oncology, Aarhus University Hospital, 8000 Aarhus (Denmark); Bassler, Niels [Department of Physics and Astronomy, Aarhus University, 8000 Aarhus (Denmark); Sørensen, Thomas Sangild [Department of Computer Science, Aarhus University, 8000 Aarhus, Denmark and Department of Clinical Medicine, Aarhus University, 8000 Aarhus (Denmark); Seco, Joao [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School,Boston, Massachusetts 02114 (United States)

    2014-11-01T23:59:59.000Z

    Purpose: Accurately predicting the range of radiotherapy ions in vivo is important for the precise delivery of dose in particle therapy. Range uncertainty is currently the single largest contribution to the dose margins used in planning and leads to a higher dose to normal tissue. The use of ion CT has been proposed as a method to improve the range uncertainty and thereby reduce dose to normal tissue of the patient. A wide variety of ions have been proposed and studied for this purpose, but no studies evaluate the image quality obtained with different ions in a consistent manner. However, imaging doses ion CT is a concern which may limit the obtainable image quality. In addition, the imaging doses reported have not been directly comparable with x-ray CT doses due to the different biological impacts of ion radiation. The purpose of this work is to develop a robust methodology for comparing the image quality of ion CT with respect to particle therapy, taking into account different reconstruction methods and ion species. Methods: A comparison of different ions and energies was made. Ion CT projections were simulated for five different scenarios: Protons at 230 and 330 MeV, helium ions at 230 MeV/u, and carbon ions at 430 MeV/u. Maps of the water equivalent stopping power were reconstructed using a weighted least squares method. The dose was evaluated via a quality factor weighted CT dose index called the CT dose equivalent index (CTDEI). Spatial resolution was measured by the modulation transfer function. This was done by a noise-robust fit to the edge spread function. Second, the image quality as a function of the number of scanning angles was evaluated for protons at 230 MeV. In the resolution study, the CTDEI was fixed to 10 mSv, similar to a typical x-ray CT scan. Finally, scans at a range of CTDEI’s were done, to evaluate dose influence on reconstruction error. Results: All ions yielded accurate stopping power estimates, none of which were statistically different from the ground truth image. Resolution (as defined by the modulation transfer function = 10% point) was the best for the helium ions (18.21 line pairs/cm) and worst for the lower energy protons (9.37 line pairs/cm). The weighted quality factor for the different ions ranged from 1.23 for helium to 2.35 for carbon ions. For the angle study, a sharp increase in absolute error was observed below 45 distinct angles, giving the impression of a threshold, rather than smooth, limit to the number of angles. Conclusions: The method presented for comparing various ion CT modalities is feasible for practical use. While all studied ions would improve upon x-ray CT for particle range estimation, helium appears to give the best results and deserves further study for imaging.

  16. Old and new neutron stars

    SciTech Connect (OSTI)

    Ruderman, M.

    1984-09-01T23:59:59.000Z

    The youngest known radiopulsar in the rapidly spinning magnetized neutron star which powers the Crab Nebula, the remnant of the historical supernova explosion of 1054 AD. Similar neutron stars are probably born at least every few hundred years, but are less frequent than Galactic supernova explosions. They are initially sources of extreme relativistic electron and/or positron winds (approx.10/sup 38/s/sup -1/ of 10/sup 12/ eV leptons) which greatly decrease as the neutron stars spin down to become mature pulsars. After several million years these neutron stars are no longer observed as radiopulsars, perhaps because of large magnetic field decay. However, a substantial fraction of the 10/sup 8/ old dead pulsars in the Galaxy are the most probable source for the isotropically distributed ..gamma..-ray burst detected several times per week at the earth. Some old neutron stars are spun-up by accretion from companions to be resurrected as rapidly spinning low magnetic field radiopulsars. 52 references, 6 figures, 3 tables.

  17. BF3 Neutron Detector Tests

    SciTech Connect (OSTI)

    Kouzes, Richard T.; Ely, James H.; Lintereur, Azaree T.; Siciliano, Edward R.; Woodring, Mitchell L.

    2009-12-09T23:59:59.000Z

    Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. The currently deployed radiation portal monitors (RPMs) from Ludlum and Science Applications International Corporation (SAIC) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large neutron detector. There is a declining supply of 3He in the world; thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and detection capabilities are being investigated. Reported here are the results of tests of the efficiency of BF3 tubes at a pressure of 800 torr. These measurements were made partially to validate models of the RPM system that have been modified to simulate the performance of BF3-filled tubes. While BF3 could be a potential replacement for 3He, there are limitations to its use in deployed systems.

  18. Neutronic fuel element fabrication

    DOE Patents [OSTI]

    Korton, George (Cincinnati, OH)

    2004-02-24T23:59:59.000Z

    This disclosure describes a method for metallurgically bonding a complete leak-tight enclosure to a matrix-type fuel element penetrated longitudinally by a multiplicity of coolant channels. Coolant tubes containing solid filler pins are disposed in the coolant channels. A leak-tight metal enclosure is then formed about the entire assembly of fuel matrix, coolant tubes and pins. The completely enclosed and sealed assembly is exposed to a high temperature and pressure gas environment to effect a metallurgical bond between all contacting surfaces therein. The ends of the assembly are then machined away to expose the pin ends which are chemically leached from the coolant tubes to leave the coolant tubes with internal coolant passageways. The invention described herein was made in the course of, or under, a contract with the U.S. Atomic Energy Commission. It relates generally to fuel elements for neutronic reactors and more particularly to a method for providing a leak-tight metal enclosure for a high-performance matrix-type fuel element penetrated longitudinally by a multiplicity of coolant tubes. The planned utilization of nuclear energy in high-performance, compact-propulsion and mobile power-generation systems has necessitated the development of fuel elements capable of operating at high power densities. High power densities in turn require fuel elements having high thermal conductivities and good fuel retention capabilities at high temperatures. A metal clad fuel element containing a ceramic phase of fuel intimately mixed with and bonded to a continuous refractory metal matrix has been found to satisfy the above requirements. Metal coolant tubes penetrate the matrix to afford internal cooling to the fuel element while providing positive fuel retention and containment of fission products generated within the fuel matrix. Metal header plates are bonded to the coolant tubes at each end of the fuel element and a metal cladding or can completes the fuel-matrix enclosure by encompassing the sides of the fuel element between the header plates.

  19. Multicriteria optimization of the spatial dose distribution

    SciTech Connect (OSTI)

    Schlaefer, Alexander [Medical Robotics Group, Universität zu Lübeck, Lübeck 23562, Germany and Institute of Medical Technology, Hamburg University of Technology, Hamburg 21073 (Germany)] [Medical Robotics Group, Universität zu Lübeck, Lübeck 23562, Germany and Institute of Medical Technology, Hamburg University of Technology, Hamburg 21073 (Germany); Viulet, Tiberiu [Medical Robotics Group, Universität zu Lübeck, Lübeck 23562 (Germany)] [Medical Robotics Group, Universität zu Lübeck, Lübeck 23562 (Germany); Muacevic, Alexander; Fürweger, Christoph [European CyberKnife Center Munich, Munich 81377 (Germany)] [European CyberKnife Center Munich, Munich 81377 (Germany)

    2013-12-15T23:59:59.000Z

    Purpose: Treatment planning for radiation therapy involves trade-offs with respect to different clinical goals. Typically, the dose distribution is evaluated based on few statistics and dose–volume histograms. Particularly for stereotactic treatments, the spatial dose distribution represents further criteria, e.g., when considering the gradient between subregions of volumes of interest. The authors have studied how to consider the spatial dose distribution using a multicriteria optimization approach.Methods: The authors have extended a stepwise multicriteria optimization approach to include criteria with respect to the local dose distribution. Based on a three-dimensional visualization of the dose the authors use a software tool allowing interaction with the dose distribution to map objectives with respect to its shape to a constrained optimization problem. Similarly, conflicting criteria are highlighted and the planner decides if and where to relax the shape of the dose distribution.Results: To demonstrate the potential of spatial multicriteria optimization, the tool was applied to a prostate and meningioma case. For the prostate case, local sparing of the rectal wall and shaping of a boost volume are achieved through local relaxations and while maintaining the remaining dose distribution. For the meningioma, target coverage is improved by compromising low dose conformality toward noncritical structures. A comparison of dose–volume histograms illustrates the importance of spatial information for achieving the trade-offs.Conclusions: The results show that it is possible to consider the location of conflicting criteria during treatment planning. Particularly, it is possible to conserve already achieved goals with respect to the dose distribution, to visualize potential trade-offs, and to relax constraints locally. Hence, the proposed approach facilitates a systematic exploration of the optimal shape of the dose distribution.

  20. Neutron Imaging of Diesel Particulate Filters

    Broader source: Energy.gov (indexed) [DOE]

    August 3 2009 Non-invasive, non-destructive technique based on attenuation of the neutron beam. Neutrons interact with nuclei and their scattering power does not vary in...

  1. 10th LANSCE School on Neutron Scattering

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    10th LANSCE School on Neutron Scattering LANSCE 10th LANSCE School on Neutron Scattering Home Abstract Lecturers Hands-On Experiments Free Day About the School Sponsors FAQ's...

  2. SEARCH FOR NEUTRON ANTI-NEUTRON OSCILLATION AT THE SUDBURY NEUTRINO OBSERVATORY

    E-Print Network [OSTI]

    Waltham, Chris

    SEARCH FOR NEUTRON ANTI-NEUTRON OSCILLATION AT THE SUDBURY NEUTRINO OBSERVATORY A Thesis Presented to explain the baryon asymmetry of the universe. In this thesis, a limit on the neutron anti-neutron (nnbar is sampled from the three phases of the SNO experiment to construct a three-phase blind analysis. The profile

  3. Neutron scattering and models: Titanium

    SciTech Connect (OSTI)

    Smith, A.B.

    1997-07-01T23:59:59.000Z

    Differential neutron elastic-scattering cross sections of elemental titanium were measured from 4.5 {r_arrow} 10.0 MeV in incident energy increments of {approx} 0.5 MeV. At each energy the measurements were made at forty or more scattering angles distributed between {approx} 17 and 160{degree}. Concurrently, differential neutron inelastic-scattering cross sections were measured for observed excitations of 0.975 {+-} 0.034, 1.497 {+-} 0.033, 2.322 {+-} 0.058, 3.252 {+-} 0.043, 3.700 {+-} 0.093, 4.317 {+-} 0.075 and 4.795 {+-} 0.100 MeV. All of the observed inelastically-scattered neutron groups were composites of contributions from several isotopes and/or levels. The experimental results were used to develop energy-average optical, statistical and coupled-channels models.

  4. PACKAGING CERTIFICATION PROGRAM METHODOLOGY FOR DETERMINING DOSE RATES FOR SMALL GRAM QUANTITIES IN SHIPPING PACKAGINGS

    SciTech Connect (OSTI)

    Nathan, S.; Loftin, B.; Abramczyk, G.; Bellamy, S.

    2012-05-09T23:59:59.000Z

    The Small Gram Quantity (SGQ) concept is based on the understanding that small amounts of hazardous materials, in this case radioactive materials (RAM), are significantly less hazardous than large amounts of the same materials. This paper describes a methodology designed to estimate an SGQ for several neutron and gamma emitting isotopes that can be shipped in a package compliant with 10 CFR Part 71 external radiation level limits regulations. These regulations require packaging for the shipment of radioactive materials, under both normal and accident conditions, to perform the essential functions of material containment, subcriticality, and maintain external radiation levels within the specified limits. By placing the contents in a helium leak-tight containment vessel, and limiting the mass to ensure subcriticality, the first two essential functions are readily met. Some isotopes emit sufficiently strong photon radiation that small amounts of material can yield a large dose rate outside the package. Quantifying the dose rate for a proposed content is a challenging issue for the SGQ approach. It is essential to quantify external radiation levels from several common gamma and neutron sources that can be safely placed in a specific packaging, to ensure compliance with federal regulations. The Packaging Certification Program (PCP) Methodology for Determining Dose Rate for Small Gram Quantities in Shipping Packagings provides bounding shielding calculations that define mass limits compliant with 10 CFR 71.47 for a set of proposed SGQ isotopes. The approach is based on energy superposition with dose response calculated for a set of spectral groups for a baseline physical packaging configuration. The methodology includes using the MCNP radiation transport code to evaluate a family of neutron and photon spectral groups using the 9977 shipping package and its associated shielded containers as the base case. This results in a set of multipliers for 'dose per particle' for each spectral group. For a given isotope, the source spectrum is folded with the response for each group. The summed contribution from all isotopes determines the total dose from the RAM in the container.

  5. Dynamically accumulated dose and 4D accumulated dose for moving tumors

    SciTech Connect (OSTI)

    Li Heng; Li Yupeng; Zhang Xiaodong; Li Xiaoqiang; Liu Wei; Gillin, Michael T.; Zhu, X. Ronald [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)

    2012-12-15T23:59:59.000Z

    Purpose: The purpose of this work was to investigate the relationship between dynamically accumulated dose (dynamic dose) and 4D accumulated dose (4D dose) for irradiation of moving tumors, and to quantify the dose uncertainty induced by tumor motion. Methods: The authors established that regardless of treatment modality and delivery properties, the dynamic dose will converge to the 4D dose, instead of the 3D static dose, after multiple deliveries. The bounds of dynamic dose, or the maximum estimation error using 4D or static dose, were established for the 4D and static doses, respectively. Numerical simulations were performed (1) to prove the principle that for each phase, after multiple deliveries, the average number of deliveries for any given time converges to the total number of fractions (K) over the number of phases (N); (2) to investigate the dose difference between the 4D and dynamic doses as a function of the number of deliveries for deliveries of a 'pulsed beam'; and (3) to investigate the dose difference between 4D dose and dynamic doses as a function of delivery time for deliveries of a 'continuous beam.' A Poisson model was developed to estimate the mean dose error as a function of number of deliveries or delivered time for both pulsed beam and continuous beam. Results: The numerical simulations confirmed that the number of deliveries for each phase converges to K/N, assuming a random starting phase. Simulations for the pulsed beam and continuous beam also suggested that the dose error is a strong function of the number of deliveries and/or total deliver time and could be a function of the breathing cycle, depending on the mode of delivery. The Poisson model agrees well with the simulation. Conclusions: Dynamically accumulated dose will converge to the 4D accumulated dose after multiple deliveries, regardless of treatment modality. Bounds of the dynamic dose could be determined using quantities derived from 4D doses, and the mean dose difference between the dynamic dose and 4D dose as a function of number of deliveries and/or total deliver time was also established.

  6. LAT and Solar Neutrons: Preliminary estimates

    SciTech Connect (OSTI)

    Longo, Francesco [Department of Physics, University of Trieste, Trieste, via Valerio 2, 34127 Trieste (Italy)]|[INFN, Trieste, via Valerio 2, 34127 Trieste (Italy)

    2007-07-12T23:59:59.000Z

    GLAST LAT will detect several solar flares in gamma rays. Motivated by the CGRO results on neutrons emitted during a solar flare, we try to estimate the possibility of the LAT to detect solar neutrons. Besides gamma rays, neutrons could indeed interact in the LAT instrument and mimic a gamma-ray signal. An estimate of the contamination of gamma-ray detection in solar flares by the neutron component is given.

  7. Nuclear Physics of Neutron Stars

    E-Print Network [OSTI]

    J. Piekarewicz

    2009-01-28T23:59:59.000Z

    Understanding the equation of state (EOS) of cold nuclear matter, namely, the relation between the pressure and energy density, is a central goal of nuclear physics that cuts across a variety of disciplines. Indeed, the limits of nuclear existence, the collision of heavy ions, the structure of neutron stars, and the dynamics of core-collapse supernova, all depend critically on the equation of state of hadronic matter. In this contribution I will concentrate on the special role that nuclear physics plays in constraining the EOS of cold baryonic matter and its impact on the properties of neutron stars.

  8. CHINA SPALLATION NEUTRON SOURCE DESIGN.

    SciTech Connect (OSTI)

    WEI,J.

    2007-01-29T23:59:59.000Z

    The China Spallation Neutron Source (CSNS) is an accelerator-based high-power project currently in preparation under the direction of the Chinese Academy of Sciences (CAS). The complex is based on an H- linear accelerator, a rapid cycling proton synchrotron accelerating the beam to 1.6 GeV, a solid tungsten target station, and five initial instruments for spallation neutron applications. The facility will operate at 25 Hz repetition rate with a phase-I beam power of about 120 kW. The major challenge is to build a robust and reliable user's facility with upgrade potential at a fractional of ''world standard'' cost.

  9. High-pressure neutron diffraction

    SciTech Connect (OSTI)

    Xu, Hongwu [Los Alamos National Laboratory

    2011-01-10T23:59:59.000Z

    This lecture will cover progress and prospect of applications of high-pressure neutron diffraction techniques to Earth and materials sciences. I will first introduce general high-pressure research topics and available in-situ high-pressure techniques. Then I'll talk about high-pressure neutron diffraction techniques using two types of pressure cells: fluid-driven and anvil-type cells. Lastly, I will give several case studies using these techniques, particularly, those on hydrogen-bearing materials and magnetic transitions.

  10. Neutron Transversity at Jefferson Lab

    SciTech Connect (OSTI)

    Jian-Ping Chen; Xiaodong Jiang; Jen-chieh Peng; Lingyan Zhu

    2005-09-07T23:59:59.000Z

    Nucleon transversity and single transverse spin asymmetries have been the recent focus of large efforts by both theorists and experimentalists. On-going and planned experiments from HERMES, COMPASS and RHIC are mostly on the proton or the deuteron. Presented here is a planned measurement of the neutron transversity and single target spin asymmetries at Jefferson Lab in Hall A using a transversely polarized {sup 3}He target. Also presented are the results and plans of other neutron transverse spin experiments at Jefferson Lab. Finally, the factorization for semi-inclusive DIS studies at Jefferson Lab is discussed.

  11. Neutron Science | More Science | ORNL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy:Nanowire Solar541,9337, 2011 at3,Neutron Scattering3 Neutron

  12. Space and camera path reconstruction for omni-directional vision

    E-Print Network [OSTI]

    Knill, Oliver

    2007-01-01T23:59:59.000Z

    In this paper, we address the inverse problem of reconstructing a scene as well as the camera motion from the image sequence taken by an omni-directional camera. Our structure from motion results give sharp conditions under which the reconstruction is unique. For example, if there are three points in general position and three omni-directional cameras in general position, a unique reconstruction is possible up to a similarity. We then look at the reconstruction problem with m cameras and n points, where n and m can be large and the over-determined system is solved by least square methods. The reconstruction is robust and generalizes to the case of a dynamic environment where landmarks can move during the movie capture. Possible applications of the result are computer assisted scene reconstruction, 3D scanning, autonomous robot navigation, medical tomography and city reconstructions.

  13. SU-E-T-43: Analytical Model for Photon Peripheral Dose in Radiotherapy Treatments

    SciTech Connect (OSTI)

    Nieto, B Sanchez; El far, R [Instituto de Fisica, Pontificia Universidad Catolica de Chile, Santiago, Santiago De Chile (Chile); Romero-Exposito, M [Universitat Autonoma de Barcelona, Barcelona (Spain); Lagares, J [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, Madrid (Spain); Mateo, JC [Hospital Duques del Infantado, Sevilla (Spain); Terron, JA [Servicio de Radiofisica, Hospital Universitario Virgen Macarena, Sevilla (Spain); Irazola, L; Sanchez-Doblado, F [Servicio de Radiofisica, Hospital Universitario Virgen Macarena, Sevilla (Spain); Departamento de Fisiologia Medica y Biofisica, Universidad de Sevilla, Sevilla (Spain)

    2014-06-01T23:59:59.000Z

    Purpose: The higher survival rate of radiotherapy patients entails a growing concern on second cancers associated to peripheral doses. Currently, dosimetry of out-of field doses is still under development. Our group has developed a methodology to estimate neutron equivalent dose in organs (1,2). We aimed to propose a model to estimate out-of-field photon doses in isocentric treatments from basic clinical data. Methods: The proposed function models the dose as the sum of leakage and scatter terms. The latter is modeled as a virtual source at the collimator, which suffers from attenuation in air and tissue, corrected by the inverse-square-law. The model was parameterized using experimental measurements with TLD700 chips placed inside an anthropomorphic phantom (6–18MV) irradiated with conformal and modulated techniques in Elekta, Siemens and Varian linacs. This model provides photon dose at a point as a function of clinical parameters as prescription dose/UM, PTV volume, distance to the field edge, height of the MLC leaves and distance from the the MLC to the isocenter. Model was tested against independent measurements (TLD100) for a VMAT treatment on a Elekta. Dose to organs is modeled from dose to points along the head-to-feet axis of the organ of a “standard man” escalated by patient height. Results: Our semi-empirical model depends on 3 given parameters (leakage parameter can be individualized). A novelty of our model, over other models (e.g., PERIDOSE), arises from its applicability to any technique (independently of the number of MU needed to deliver a dose). Differences between predictions and measurements were < 0.005mSv/UM. Conclusion: We have proposed a unique model which successfully account for photon peripheral organ dose. This model can be applied in the day-to-day clinic as it only needs a few basic parameters which are readily accessible.1. Radiother. Oncol. 107:234–243, 2013. 2. Phys. Med. Biol. 57:6167–6191, 2012.

  14. A neutron transmission study of environmental Gd

    E-Print Network [OSTI]

    Cristiana Oprea; Ioan Alexandru Oprea; Alexandru Mihul

    2014-06-02T23:59:59.000Z

    A new method for the determination of environmental Gd by neutron transmission (NT) experiments is proposed. The NT method is based on the measurements of neutron spectra passing through a target. From the attenuation neutron spectra new data as concentration, width, resonance energies and cross section have been obtained.

  15. Neutron Scattering Studies of Correlated Electron Systems

    E-Print Network [OSTI]

    Boothroyd, Andrew

    Neutron Scattering Studies of Correlated Electron Systems Lucy Helme Thesis submitted submitted for the Degree of Doctor of Philosophy, Trinity Term 2006 This thesis presents neutron scatteringO2, through inelastic neutron scattering studies of the crystal field transitions above and below

  16. RisR1125(EN) Neutron Scattering

    E-Print Network [OSTI]

    Risø­R­1125(EN) Neutron Scattering Studies of Modulated Magnetic Structures Steen Aagaard Sørensen investigations of the magnetic systems DyFe4Al8 and MnSi by neutron scattering and in the former case also by X and the correlations between the scattering entities of the sample. The theoretical framework of neutron scattering

  17. Measurements of the Thermal Neutron Scattering Kernel

    E-Print Network [OSTI]

    Danon, Yaron

    Measurements of the Thermal Neutron Scattering Kernel Li (Emily) Liu, Yaron Danon, Bjorn Becker and discussions Problems and Future study Questions #12;3 M. Mattes and J. Keinert, Thermal Neutron Scattering experimental data used was from 1973-1974! M. Mattes and J. Keinert, Thermal Neutron Scattering Data

  18. Neutron production enhancements for the Intense Pulsed Neutron Source.

    SciTech Connect (OSTI)

    Iverson, E. B.

    1999-01-04T23:59:59.000Z

    The Intense Pulsed Neutron Source (IPNS) was the first high energy spallation neutron source in the US dedicated to materials research. It has operated for sixteen years, and in that time has had a very prolific record concerning the development of new target and moderator systems for pulsed spallation sources. IPNS supports a very productive user program on its thirteen instruments, which are oversubscribed by more than two times, meanwhile having an excellent overall reliability of 95%. Although the proton beam power is relatively low at 7 kW, the target and moderator systems are very efficient. The typical beam power which gives an equivalent flux for long-wavelength neutrons is about 60 kW, due to the use of a uranium target and liquid and solid methane moderators, precluded at some sources due to a higher accelerator power. The development of new target and moderator systems is by no means stagnant at IPNS. They are presently considering numerous enhancements to the target and moderators that offer prospects for increasing the useful neutron production by substantial factors. Many of these enhancements could be combined, although their combined benefit has not yet been well established. Meanwhile, IPNS is embarking on a coherent program of study concerning these improvements and their possible combination and implementation. Moreover, any improvements accomplished at IPNS would immediately increase the performance of IPNS instruments.

  19. 2002 REVIEW OF NEUTRON AND NON NEUTRON NUCLEAR DATA.

    SciTech Connect (OSTI)

    HOLDEN,N.E.

    2002-08-18T23:59:59.000Z

    Review articles are in preparation for the 2003 edition of the CRC's Handbook of Chemistry and Physics dealing with both non-neutron and neutron nuclear data. Highlights include: withdrawal of the claim for discovery of element 118; new measurements of isotopic abundances have led to changes for many elements; a new set of recommended standards for calibration of {gamma}-ray energies have been published for many nuclides; new half-life measurements reported for very short lived isotopes, many long-lived nuclides and {beta}{beta} decay measurements for quasi-stable nuclides; a new reassessment of spontaneous fission (sf) half-lives for ground state nuclides, distinguishing half-lives from sf decay and cluster decay half-lives and the new cluster-fission decay; charged particle cross sections, (n,p) and (n,{alpha}) measurements for thermal neutrons incident on light nuclides; new thermal (n,{gamma}) cross sections and neutron resonance integrals measured. Details are presented.

  20. Scattered Neutron Tomography Based on A Neutron Transport Inverse Problem

    SciTech Connect (OSTI)

    William Charlton

    2007-07-01T23:59:59.000Z

    Neutron radiography and computed tomography are commonly used techniques to non-destructively examine materials. Tomography refers to the cross-sectional imaging of an object from either transmission or reflection data collected by illuminating the object from many different directions.

  1. Neutron producing target for accelerator based neutron source for

    E-Print Network [OSTI]

    Taskaev, Sergey Yur'evich

    therapy [1, 2]. Lithium targets for two modes of neutron beam production are developed. The first one. Target will be created as a 2 ­ 3 µm thick lithium layer on the surface of tungsten disk cooled by liquidW cm­2 . ii) Production of target with lithium layer thickness of 2 ­ 3 µm. #12;248 iii) Evaporation

  2. Light-flavor squark reconstruction at CLIC

    E-Print Network [OSTI]

    Simon, Frank

    2015-01-01T23:59:59.000Z

    We present a simulation study of the prospects for the mass measurement of TeV-scale light-flavored right-handed squark at a 3 TeV e+e- collider based on CLIC technology. The analysis is based on full GEANT4 simulations of the CLIC_ILD detector concept, including Standard Model physics backgrounds and beam-induced hadronic backgrounds from two-photon processes. The analysis serves as a generic benchmark for the reconstruction of highly energetic jets in events with substantial missing energy. Several jet finding algorithms were evaluated, with the longitudinally invariant kt algorithm showing a high degree of robustness towards beam-induced background while preserving the features typically found in algorithms developed for e+e- collisions. The presented study of the reconstruction of light-flavored squarks shows that for TeV-scale squark masses, sub-percent accuracy on the mass measurement can be achieved at CLIC.

  3. Light-flavor squark reconstruction at CLIC

    E-Print Network [OSTI]

    Simon, Frank Richard

    2015-01-01T23:59:59.000Z

    We present a simulation study of the prospects for the mass measurement of TeV-scale light- flavored right-handed squark at a 3 TeV e+e collider based on CLIC technology. The analysis is based on full GEANT4 simulations of the CLIC_ILD detector concept, including Standard Model physics backgrounds and beam-induced hadronic backgrounds from two- photon processes. The analysis serves as a generic benchmark for the reconstruction of highly energetic jets in events with substantial missing energy. Several jet finding algorithms were evaluated, with the longitudinally invariant kt algorithm showing a high degree of robustness towards beam-induced background while preserving the features typically found in algorithms developed for e+e- collisions. The presented study of the reconstruction of light-flavored squarks shows that for TeV-scale squark masses, sub-percent accuracy on the mass measurement can be achieved at CLIC.

  4. Reconstructing Spatial Distributions from Anonymized Locations

    SciTech Connect (OSTI)

    Horey, James L [ORNL] [ORNL; Forrest, Stephanie [University of New Mexico, Albuquerque] [University of New Mexico, Albuquerque; Groat, Michael [University of New Mexico, Albuquerque] [University of New Mexico, Albuquerque

    2012-01-01T23:59:59.000Z

    Devices such as mobile phones, tablets, and sensors are often equipped with GPS that accurately report a person's location. Combined with wireless communication, these devices enable a wide range of new social tools and applications. These same qualities, however, leave location-aware applications vulnerable to privacy violations. This paper introduces the Negative Quad Tree, a privacy protection method for location aware applications. The method is broadly applicable to applications that use spatial density information, such as social applications that measure the popularity of social venues. The method employs a simple anonymization algorithm running on mobile devices, and a more complex reconstruction algorithm on a central server. This strategy is well suited to low-powered mobile devices. The paper analyzes the accuracy of the reconstruction method in a variety of simulated and real-world settings and demonstrates that the method is accurate enough to be used in many real-world scenarios.

  5. Smoothing spline primordial power spectrum reconstruction

    E-Print Network [OSTI]

    Carolyn Sealfon; Licia Verde; Raul Jimenez

    2005-11-01T23:59:59.000Z

    We reconstruct the shape of the primordial power spectrum (PPS) using a smoothing spline. Our adapted smoothing spline technique provides a complementary method to existing efforts to search for smooth features in the PPS, such as a running spectral index. With this technique we find no significant indication with WMAP first-year data that the PPS deviates from Harrison-Zeldovich and no evidence for loss of power on large scales. We also examine the effect on the cosmological parameters of the additional PPS freedom. Smooth variations in the PPS are not significantly degenerate with other cosmological parameters, but the spline reconstruction greatly increases the errors on the optical depth and baryon fraction.

  6. Neutron capture therapy with deep tissue penetration using capillary neutron focusing

    DOE Patents [OSTI]

    Peurrung, A.J.

    1997-08-19T23:59:59.000Z

    An improved method is disclosed for delivering thermal neutrons to a subsurface cancer or tumor which has been first doped with a dopant having a high cross section for neutron capture. The improvement is the use of a guide tube in cooperation with a capillary neutron focusing apparatus, or neutron focusing lens, for directing neutrons to the tumor, and thereby avoiding damage to surrounding tissue. 1 fig.

  7. Moment of Fluid Interface Reconstruction with Filaments

    SciTech Connect (OSTI)

    Jemison, Matthew B. [Los Alamos National Laboratory

    2012-08-15T23:59:59.000Z

    A moving system made up of multiple fluids (e.g. air and water) may be defined by an evolving interface with a changing topology. MOF uses a piecewise linear interface reconstruction to numerically model deforming boundaries. Given a volume fraction V and reference centroid x for a material in cell {Omega}, we seek to find an interface {Gamma} that exactly captures V and minimizes error in x. This differs from Volume of Fluid methods.

  8. Cheminformatics for genome-scale metabolic reconstructions

    E-Print Network [OSTI]

    May, John W.

    2015-01-06T23:59:59.000Z

    of a cell can be organised and studied as a cellular wiring diagram, a genetic circuit. Different realisations of genetic circuits have been created and applied to multiple cellular processes, including but not limited to: regulation, signalling... -SEED web application is an automated pipeline for high-throughput cre- ation of draft reconstructions [59]. Although described as draft, steps listed in the re- finement and validation stages are included. The auto-complete optimisation proce- dure resolves...

  9. Santo Antonio de Tanna? story and reconstruction 

    E-Print Network [OSTI]

    Fraga, Tiago Miguel

    2008-10-10T23:59:59.000Z

    of the requirements for the degree of MASTER OF ARTS Approved by: Chair of Committee, Luis Filipe Vieira de Castro Committee Members, Kevin J. Crisman James M. Rosenheim Head of Department, Donny L. Hamilton December 2007 Major Subject: Anthropology... iii ABSTRACT Santo Antonio de Tanná: Story and Reconstruction. (December 2007) Tiago Miguel Fraga, Lic., Lusiada University Chair of Advisory Committee: Dr. Luis Filipe Vieira de Castro Buy a puzzle, assemble it, and destroy its original box...

  10. Santo Antonio de Tanna story and reconstruction 

    E-Print Network [OSTI]

    Fraga, Tiago Miguel

    2009-05-15T23:59:59.000Z

    of the requirements for the degree of MASTER OF ARTS Approved by: Chair of Committee, Luis Filipe Vieira de Castro Committee Members, Kevin J. Crisman James M. Rosenheim Head of Department, Donny L. Hamilton December 2007 Major Subject: Anthropology... iii ABSTRACT Santo Antonio de Tann?: Story and Reconstruction. (December 2007) Tiago Miguel Fraga, Lic., Lusiada University Chair of Advisory Committee: Dr. Luis Filipe Vieira de Castro Buy a puzzle, assemble it, and destroy its original box...

  11. Scalable Reconstruction of Unitary Processes and Hamiltonians

    E-Print Network [OSTI]

    M. Holzäpfel; T. Baumgratz; M. Cramer; M. B. Plenio

    2014-11-24T23:59:59.000Z

    Based on recently introduced efficient quantum state tomography schemes, we propose a scalable method for the tomography of unitary processes and the reconstruction of Hamiltonians. As opposed to the exponential scaling with the number of subsystems of standard quantum process tomography, the method relies only on measurements of linearly many local observables and either (a) the ability to prepare eigenstates of locally informationally complete operators or (b) access to an ancilla of the same size as the to-be-characterized system and the ability to prepare a maximally entangled state on the combined system. As such, the method requires at most linearly many states to be prepared and linearly many observables to be measured. The quality of the reconstruction can be quantified with the same experimental resources that are required to obtain the reconstruction in the first place. Our numerical simulations of several quantum circuits and local Hamiltonians suggest a polynomial scaling of the total number of measurements and post-processing resources.

  12. A GREEN'S FUNCTION APPROACH FOR DETERMINING DOSE RATES FOR SMALL GRAM QUANTITIES IN SHIPPING PACKAGINGS

    SciTech Connect (OSTI)

    Nathan, S.

    2012-06-14T23:59:59.000Z

    The Small Gram Quantity (SGQ) concept is based on the understanding that small amounts of hazardous materials, in this case radioactive materials (RAM), are significantly less hazardous than large amounts of the same materials. This paper describes a methodology designed to estimate an SGQ for several neutron and gamma emitting isotopes that can be shipped in a package in compliance with 10 CFR Part 71 external radiation level limits regulations. The neutron and photon sources were calculated using both ORIGEN-S and RASTA. The response from a unit source in each neutron and photon group was calculated using MCNP5 with each unshielded and shielded container configuration. Effects of self-shielding on both neutron and photon response were evaluated by including either plutonium oxide or iron in the source region for the case with no shielded container. For the cases of actinides mixed with light elements, beryllium is the bounding light element. The added beryllium (10 to 90 percent of the actinide mass) in the cases studied represents between 9 and 47 percent concentration of the total mixture mass. For beryllium concentrations larger than 50 percent, the increase in the neutron source term and dose rate tend to increase at a much lower rate than at concentrations lower than 50%. The intimately mixed actinide-beryllium form used in these models is very conservative and thus the limits presented in this report are practical bounds on the mass that can be safely shipped. The calculated dose rate from one gram of each isotope was then used to determin the maximum amount of a single isotope that could be shipped in the Model 9977 Package (or packagings having the same or larger external dimensions as well as similar structural materials) and have the external radiation level within the regulatory dose limits at the surface of the package. The estimates of the mass limits presented would also serve as conservative limits for both the Models 9975 and 9978 packages. If a package contains a mixture of isotopes, the acceptability for shipment can be determined by a sum of fractions approach. It should be noted that the SGQ masses presented in this report represent limits that would comply with the external radiation limits under 10CFR Part 71. They do not necessarily bound lower limits that may be required to comply with other factors such as heat load of the package.

  13. Characterization of statistical prior image constrained compressed sensing (PICCS): II. Application to dose reduction

    SciTech Connect (OSTI)

    Lauzier, Pascal Theriault; Chen Guanghong [Medical Physics Department, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States)

    2013-02-15T23:59:59.000Z

    Purpose: The ionizing radiation imparted to patients during computed tomography exams is raising concerns. This paper studies the performance of a scheme called dose reduction using prior image constrained compressed sensing (DR-PICCS). The purpose of this study is to characterize the effects of a statistical model of x-ray detection in the DR-PICCS framework and its impact on spatial resolution. Methods: Both numerical simulations with known ground truth and in vivo animal dataset were used in this study. In numerical simulations, a phantom was simulated with Poisson noise and with varying levels of eccentricity. Both the conventional filtered backprojection (FBP) and the PICCS algorithms were used to reconstruct images. In PICCS reconstructions, the prior image was generated using two different denoising methods: a simple Gaussian blur and a more advanced diffusion filter. Due to the lack of shift-invariance in nonlinear image reconstruction such as the one studied in this paper, the concept of local spatial resolution was used to study the sharpness of a reconstructed image. Specifically, a directional metric of image sharpness, the so-called pseudopoint spread function (pseudo-PSF), was employed to investigate local spatial resolution. Results: In the numerical studies, the pseudo-PSF was reduced from twice the voxel width in the prior image down to less than 1.1 times the voxel width in DR-PICCS reconstructions when the statistical model was not included. At the same noise level, when statistical weighting was used, the pseudo-PSF width in DR-PICCS reconstructed images varied between 1.5 and 0.75 times the voxel width depending on the direction along which it was measured. However, this anisotropy was largely eliminated when the prior image was generated using diffusion filtering; the pseudo-PSF width was reduced to below one voxel width in that case. In the in vivo study, a fourfold improvement in CNR was achieved while qualitatively maintaining sharpness; images also had a qualitatively more uniform noise spatial distribution when including a statistical model. Conclusions: DR-PICCS enables to reconstruct CT images with lower noise than FBP and the loss of spatial resolution can be mitigated to a large extent. The introduction of statistical modeling in DR-PICCS may improve some noise characteristics, but it also leads to anisotropic spatial resolution properties. A denoising method, such as the directional diffusion filtering, has been demonstrated to reduce anisotropy in spatial resolution effectively when it was combined with DR-PICCS with statistical modeling.

  14. Measurement of routinely encountered neutron field doses using portable survey instruments and a Bonner multisphere system

    E-Print Network [OSTI]

    Davis, Donald Reed

    1981-01-01T23:59:59.000Z

    Ludlum Model 15 NSC-A NSC-8 NSC-C NSC-D NSC-E NSC-F NSC-G NSC-H NSC-I NSC-J NSC-K NSC-L NSC-M 30. 19 mRem/hr 4. 38 2. 70 1. 54 4. 08 4. 31 5. 42 10. 91 4. 19 0. 48 0. 46 3. 64 0. 50 1000 mRem/hr 90 58 36 140 125 90 32 25... 20 17 70 10 950 mRem/hr 120 40 32 160 135 80 45 28 16 11 86 8 2 CYC-A CYC-8 CYC-C CYC-D CYC-E CYC-F 31 . 11 25. 23 3. 19 1. 95 1. 02 1. 96 1000 190 75 32 14 20 1550 176 72 23 15 24 denotes measurement made...

  15. Maximally incompressible neutron star matter

    E-Print Network [OSTI]

    Timothy S. Olson

    2000-12-07T23:59:59.000Z

    Relativistic kinetic theory, based on the Grad method of moments as developed by Israel and Stewart, is used to model viscous and thermal dissipation in neutron star matter and determine an upper limit on the maximum mass of neutron stars. In the context of kinetic theory, the equation of state must satisfy a set of constraints in order for the equilibrium states of the fluid to be thermodynamically stable and for perturbations from equilibrium to propagate causally via hyperbolic equations. Application of these constraints to neutron star matter restricts the stiffness of the most incompressible equation of state compatible with causality to be softer than the maximally incompressible equation of state that results from requiring the adiabatic sound speed to not exceed the speed of light. Using three equations of state based on experimental nucleon-nucleon scattering data and properties of light nuclei up to twice normal nuclear energy density, and the kinetic theory maximally incompressible equation of state at higher density, an upper limit on the maximum mass of neutron stars averaging 2.64 solar masses is derived.

  16. Neutron Detection via Bubble Chambers

    SciTech Connect (OSTI)

    Jordan, David V.; Ely, James H.; Peurrung, Anthony J.; Bond, Leonard J.; Collar, J. I.; Flake, Matthew; Knopf, Michael A.; Pitts, W. K.; Shaver, Mark W.; Sonnenschein, Andrew; Smart, John E.; Todd, Lindsay C.

    2005-10-06T23:59:59.000Z

    The results of a Pacific Northwest National Laboratory (PNNL) exploratory research project investigating the feasibility of fast neutron detection using a suitably prepared and operated, pressure-cycled bubble chamber are described. The research was conducted along two parallel paths. Experiments with a slow pressure-release Halon chamber at the Enrico Fermi Institute at the University of Chicago showed clear bubble nucleation sensitivity to an AmBe neutron source and insensitivity to the 662 keV gammas from a 137Cs source. Bubble formation was documented via high-speed (1000 frames/sec) photography, and the acoustic signature of bubble formation was detected using a piezo-electric transducer element mounted on the base of the chamber. The chamber’s neutron sensitivity as a function of working fluid temperature was mapped out. The second research path consisted of the design, fabrication, and testing of a fast pressure-release Freon-134a chamber at PNNL. The project concluded with successful demonstrations of the PNNL chamber’s AmBe neutron source sensitivity and 137Cs gamma insensitivity. The source response tests of the PNNL chamber were documented with high-speed photography.

  17. Experiment Design and Analysis Guide - Neutronics & Physics

    SciTech Connect (OSTI)

    Misti A Lillo

    2014-06-01T23:59:59.000Z

    The purpose of this guide is to provide a consistent, standardized approach to performing neutronics/physics analysis for experiments inserted into the Advanced Test Reactor (ATR). This document provides neutronics/physics analysis guidance to support experiment design and analysis needs for experiments irradiated in the ATR. This guide addresses neutronics/physics analysis in support of experiment design, experiment safety, and experiment program objectives and goals. The intent of this guide is to provide a standardized approach for performing typical neutronics/physics analyses. Deviation from this guide is allowed provided that neutronics/physics analysis details are properly documented in an analysis report.

  18. Neutron sources: Present practice and future potential

    SciTech Connect (OSTI)

    Cierjacks, S.; Smith, A.B.

    1988-01-01T23:59:59.000Z

    The present capability and future potential of accelerator-based monoenergetic and white neutron sources are outlined in the context of fundamental and applied neutron-nuclear research. The neutron energy range extends from thermal to 500 MeV, and the time domain from steady-state to pico-second pulsed sources. Accelerator technology is summarized, including the production of intense light-ion, heavy-ion and electron beams. Target capabilities are discussed with attention to neutron-producing efficiency and power-handling capabilities. The status of underlying neutron-producing reactions is summarized. The present and future use of neutron sources in: fundamental neutron-nuclear research, nuclear data acquisition, materials damage studies, engineering tests, and biomedical applications are discussed. Emphasis is given to current status, near-term advances well within current technology, and to long-range projections. 90 refs., 4 figs.

  19. Neutron spectrometer for improved SNM search.

    SciTech Connect (OSTI)

    Vance, Andrew L.; Aigeldinger, Georg

    2007-03-01T23:59:59.000Z

    With the exception of large laboratory devices with very low sensitivities, a neutron spectrometer have not been built for fission neutrons such as those emitted by special nuclear materials (SNM). The goal of this work was to use a technique known as Capture Gated Neutron Spectrometry to develop a solid-state device with this functionality. This required modifications to trans-stilbene, a known solid-state scintillator. To provide a neutron capture signal we added lithium to this material. This unique triggering signal allowed identification of neutrons that lose all of their energy in the detector, eliminating uncertainties that arise due to partial energy depositions. We successfully implemented a capture gated neutron spectrometer and were able to distinguish an SNM like fission spectrum from a spectrum stemming from a benign neutron source.

  20. Radiation Dose to the Esophagus From Breast Cancer Radiation Therapy, 1943-1996: An International Population-Based Study of 414 Patients

    SciTech Connect (OSTI)

    Lamart, Stephanie, E-mail: stephanie.lamart@nih.gov [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States)] [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Stovall, Marilyn [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Simon, Steven L. [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States)] [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Smith, Susan A.; Weathers, Rita E.; Howell, Rebecca M. [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Curtis, Rochelle E. [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States)] [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Aleman, Berthe M.P. [Department of Radiotherapy, The Netherlands Cancer Institute, Amsterdam (Netherlands)] [Department of Radiotherapy, The Netherlands Cancer Institute, Amsterdam (Netherlands); Travis, Lois [Rubin Center for Cancer Survivorship and Department of Radiation Oncology, University of Rochester Medical Center, Rochester, New York (United States)] [Rubin Center for Cancer Survivorship and Department of Radiation Oncology, University of Rochester Medical Center, Rochester, New York (United States); Kwon, Deukwoo [Sylvester Comprehensive Cancer Center, University of Miami, Miami, Florida (United States)] [Sylvester Comprehensive Cancer Center, University of Miami, Miami, Florida (United States); Morton, Lindsay M. [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States)] [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States)

    2013-07-15T23:59:59.000Z

    Purpose: To provide dosimetric data for an epidemiologic study on the risk of second primary esophageal cancer among breast cancer survivors, by reconstructing the radiation dose incidentally delivered to the esophagus of 414 women treated with radiation therapy for breast cancer during 1943-1996 in North America and Europe. Methods and Materials: We abstracted the radiation therapy treatment parameters from each patient’s radiation therapy record. Treatment fields included direct chest wall (37% of patients), medial and lateral tangentials (45%), supraclavicular (SCV, 64%), internal mammary (IM, 44%), SCV and IM together (16%), axillary (52%), and breast/chest wall boosts (7%). The beam types used were {sup 60}Co (45% of fields), orthovoltage (33%), megavoltage photons (11%), and electrons (10%). The population median prescribed dose to the target volume ranged from 21 Gy to 40 Gy. We reconstructed the doses over the length of the esophagus using abstracted patient data, water phantom measurements, and a computational model of the human body. Results: Fields that treated the SCV and/or IM lymph nodes were used for 85% of the patients and delivered the highest doses within 3 regions of the esophagus: cervical (population median 38 Gy), upper thoracic (32 Gy), and middle thoracic (25 Gy). Other fields (direct chest wall, tangential, and axillary) contributed substantially lower doses (approximately 2 Gy). The cervical to middle thoracic esophagus received the highest dose because of its close proximity to the SCV and IM fields and less overlying tissue in that part of the chest. The location of the SCV field border relative to the midline was one of the most important determinants of the dose to the esophagus. Conclusions: Breast cancer patients in this study received relatively high incidental radiation therapy doses to the esophagus when the SCV and/or IM lymph nodes were treated, whereas direct chest wall, tangentials, and axillary fields contributed lower doses.

  1. An updated dose assessment for Rongelap Island

    SciTech Connect (OSTI)

    Robison, W.L.; Conrado, C.L.; Bogen, K.T.

    1994-07-01T23:59:59.000Z

    We have updated the radiological dose assessment for Rongelap Island at Rongelap Atoll using data generated from field trips to the atoll during 1986 through 1993. The data base used for this dose assessment is ten fold greater than that available for the 1982 assessment. Details of each data base are presented along with details about the methods used to calculate the dose from each exposure pathway. The doses are calculated for a resettlement date of January 1, 1995. The maximum annual effective dose is 0.26 mSv y{sup {minus}1} (26 mrem y{sup {minus}1}). The estimated 30-, 50-, and 70-y integral effective doses are 0.0059 Sv (0.59 rem), 0.0082 Sv (0.82 rem), and 0.0097 Sv (0.97 rem), respectively. More than 95% of these estimated doses are due to 137-Cesium ({sup 137}Cs). About 1.5% of the estimated dose is contributed by 90-Strontium ({sup 90}Sr), and about the same amount each by 239+240-Plutonium ({sup 239+240}PU), and 241-Americium ({sup 241}Am).

  2. EXTRAPOLATING RADIATION-INDUCED CANCER RISKS FROM LOW DOSES TO VERY LOW DOSES

    E-Print Network [OSTI]

    Brenner, David Jonathan

    risk; National Council on Radiation Protection and Measurements INTRODUCTION THERE IS considerablePaper EXTRAPOLATING RADIATION-INDUCED CANCER RISKS FROM LOW DOSES TO VERY LOW DOSES David J. Brenner* Abstract--There is strong evidence that ionizing radiation increases cancer risks at high doses

  3. Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny

    E-Print Network [OSTI]

    Yu, K.N.

    Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny in the human Abstract To calculate the absorbed dose in the human lung due to inhaled radon progeny, ICRP focussed and secretory cells). The absorbed energy for alpha particles emitted by radon progeny in the human respiratory

  4. Respiratory triggered 4D cone-beam computed tomography: A novel method to reduce imaging dose

    SciTech Connect (OSTI)

    Cooper, Benjamin J. [Radiation Physics Laboratory, Sydney Medical School, University of Sydney, NSW 2006, Australia and Department of Medical Physics and Radiation Engineering, Canberra Hospital, Canberra, ACT 2605 (Australia); O'Brien, Ricky T.; Keall, Paul J. [Radiation Physics Laboratory, Sydney Medical School, University of Sydney, NSW 2006 (Australia); Balik, Salim; Hugo, Geoffrey D. [Radiation Oncology, Virginia Commonwealth University, 401 College Street, P.O.Box 980058, Richmond, Virginia 23298-0058 (United States)

    2013-04-15T23:59:59.000Z

    Purpose: A novel method called respiratory triggered 4D cone-beam computed tomography (RT 4D CBCT) is described whereby imaging dose can be reduced without degrading image quality. RT 4D CBCT utilizes a respiratory signal to trigger projections such that only a single projection is assigned to a given respiratory bin for each breathing cycle. In contrast, commercial 4D CBCT does not actively use the respiratory signal to minimize image dose. Methods: To compare RT 4D CBCT with conventional 4D CBCT, 3600 CBCT projections of a thorax phantom were gathered and reconstructed to generate a ground truth CBCT dataset. Simulation pairs of conventional 4D CBCT acquisitions and RT 4D CBCT acquisitions were developed assuming a sinusoidal respiratory signal which governs the selection of projections from the pool of 3600 original projections. The RT 4D CBCT acquisition triggers a single projection when the respiratory signal enters a desired acquisition bin; the conventional acquisition does not use a respiratory trigger and projections are acquired at a constant frequency. Acquisition parameters studied were breathing period, acquisition time, and imager frequency. The performance of RT 4D CBCT using phase based and displacement based sorting was also studied. Image quality was quantified by calculating difference images of the test dataset from the ground truth dataset. Imaging dose was calculated by counting projections. Results: Using phase based sorting RT 4D CBCT results in 47% less imaging dose on average compared to conventional 4D CBCT. Image quality differences were less than 4% at worst. Using displacement based sorting RT 4D CBCT results in 57% less imaging dose on average, than conventional 4D CBCT methods; however, image quality was 26% worse with RT 4D CBCT. Conclusions: Simulation studies have shown that RT 4D CBCT reduces imaging dose while maintaining comparable image quality for phase based 4D CBCT; image quality is degraded for displacement based RT 4D CBCT in its current implementation.

  5. Dose reduction at nuclear power plants

    SciTech Connect (OSTI)

    Baum, J.W.; Dionne, B.J.

    1983-01-01T23:59:59.000Z

    The collective dose equivalent at nuclear power plants increased from 1250 rem in 1969 to nearly 54,000 rem in 1980. This rise is attributable primarily to an increase in nuclear generated power from 1289 MW-y to 29,155 MW-y; and secondly, to increased average plant age. However, considerable variation in exposure occurs from plant to plant depending on plant type, refueling, maintenance, etc. In order to understand the factors influencing these differences, an investigation was initiated to study dose-reduction techniques and effectiveness of as low as reasonably achievable (ALARA) planning at light water plants. Objectives are to: identify high-dose maintenance tasks and related dose-reduction techniques; investigate utilization of high-reliability, low-maintenance equipment; recommend improved radioactive waste handling equipment and procedures; examine incentives for dose reduction; and compile an ALARA handbook.

  6. Dose calculations for severe LWR accident scenarios

    SciTech Connect (OSTI)

    Margulies, T.S.; Martin, J.A. Jr.

    1984-05-01T23:59:59.000Z

    This report presents a set of precalculated doses based on a set of postulated accident releases and intended for use in emergency planning and emergency response. Doses were calculated for the PWR (Pressurized Water Reactor) accident categories of the Reactor Safety Study (WASH-1400) using the CRAC (Calculations of Reactor Accident Consequences) code. Whole body and thyroid doses are presented for a selected set of weather cases. For each weather case these calculations were performed for various times and distances including three different dose pathways - cloud (plume) shine, ground shine and inhalation. During an emergency this information can be useful since it is immediately available for projecting offsite radiological doses based on reactor accident sequence information in the absence of plant measurements of emission rates (source terms). It can be used for emergency drill scenario development as well.

  7. Delayed neutron yield from fast neutron induced fission of sup 2 sup 3 sup 8 U

    E-Print Network [OSTI]

    Piksaikin, V M; Isaev, S G; Kazakov, L E; Roshchenko, V A; Tertytchnyi, R G

    2001-01-01T23:59:59.000Z

    The measurements of the total delayed neutron yield from fast neutron induced fission of sup 2 sup 3 sup 8 U were made. The experimental method based on the periodic irradiation of the fissionable sample by neutrons from a suitable nuclear reaction had been employed. The preliminary results on the energy dependence of the total delayed neutron yield from fission of sup 2 sup 3 sup 8 U are obtained. According to the comparison of experimental data with our prediction based on correlation properties of delayed neutron characteristics, it is concluded that the value of the total delayed neutron yield near the threshold of (n,f) reaction is not a constant.

  8. Neutron occupancy of the 0d5/2 orbital and the N=16 shell closure in 24O

    E-Print Network [OSTI]

    K. Tshoo; Y. Satou; C. A. Bertulani; H. Bhang; S. Choi; T. Nakamura; Y. Kondo; S. Deguchi; Y. Kawada; Y. Nakayama; K. N. Tanaka; N. Tanaka; Y. Togano; N. Kobayashi; N. Aoi; M. Ishihara; T. Motobayashi; H. Otsu; H. Sakurai; S. Takeuchi; K. Yoneda; F. Delaunay; J. Gibelin; F. M. Marqués; N. A. Orr; T. Honda; T. Kobayashi; T. Sumikama; Y. Miyashita; K. Yoshinaga; M. Matsushita; S. Shimoura; D. Sohler; J. W. Hwang; T. Zheng; Z. H. Li; Z. X. Cao

    2014-10-27T23:59:59.000Z

    One-neutron knockout from 24O leading to the first excited state in 23O has been measured for a proton target at a beam energy of 62 MeV/nucleon. The decay energy spectrum of the neutron unbound state of 23O was reconstructed from the measured four momenta of the 22O fragment and emitted neutron. A sharp peak was found at Edecay=50$\\pm$3 keV, corresponding to an excited state in 23O at 2.78$\\pm$0.11 MeV, as observed in previous measurements. The longitudinal momentum distribution for this state was consistent with d -wave neutron knockout, providing support for a J{\\pi} assignment of 5/2+. The associated spectroscopic factor was deduced to be C2S(0d5/2)=4.1$\\pm$0.4 by comparing the measured cross section (View the MathML source) with a distorted wave impulse approximation calculation. Such a large occupancy for the neutron 0d5/2 orbital is in line with the N=16 shell closure in 24O.

  9. Preparing ATLAS reconstruction software for LHC's Run 2

    E-Print Network [OSTI]

    ATLAS Collaboration; The ATLAS collaboration

    2015-01-01T23:59:59.000Z

    In order to maximize the physics potential of the ATLAS detector during LHC's Run 2, the reconstruction software has been updated. Flat computing budgets required a factor of three improved run time, while the new xAOD data format forced changes in the reconstruction algorithms. Physics performance improvements have been made in the reconstruction of various objects, using improved techniques like multivariate discriminants, etc. This paper will present an overview of the improvements that have been made.

  10. War damages and reconstruction of Peruca dam

    SciTech Connect (OSTI)

    Nonveiller, E. [Univ. of Zagreb (Croatia). Faculty of Civil Engineering] [Univ. of Zagreb (Croatia). Faculty of Civil Engineering; Rupcic, J. [Univ. of Zagreb (Croatia). Faculty of Civil Engineering] [Univ. of Zagreb (Croatia). Faculty of Civil Engineering; [Elektroprojekt Consulting Engineering, Zagreb (Croatia); Sever, Z. [Elektroprojekt Consulting Engineering, Zagreb (Croatia)] [Elektroprojekt Consulting Engineering, Zagreb (Croatia)

    1999-04-01T23:59:59.000Z

    The paper describes the heavy damages caused by blasting in the Peruca rockfill dam in Croatia in January 1993. Complete collapse of the dam by overtopping was prevented through quick action of the dam owner by dumping clayey gravel on the lowest sections of the dam crest and opening the bottom outlet of the reservoir, thus efficiently lowering the water level. After the damages were sufficiently established and alternatives for restoration of the dam were evaluated, it was decided to construct a diaphragm wall through the damaged core in the central dam part as the impermeable dam element and to rebuild the central clay core at the dam abutments. Reconstruction works are described.

  11. Disparity coding: a technique for stereo reconstruction

    E-Print Network [OSTI]

    Bell, William Bryan

    1988-01-01T23:59:59.000Z

    . Lee for his added help. TABLE OF COiUTENTS CHAPTER I INTRODI, CTION II FUSIOU AIODEL . Page A. Noise Introduction B. Edge Detection C. Fusion D. Disparity Calculation III CHANNEL CODING . 6 . 8 13 18 21 IV IXIAGE RECONSTRUCTION V... Values for ON Type Edges Noiseless Right Stereo Image Edges Right Stereo Image Edges with a SNR of 3 dB AWGN Separation Candidate and Target Edges Noiseless, ON Type Fusion Field Image Gray ? level Values of ON Type Fusion Field Noiseless Disparity...

  12. Reconstructing Quintom from Ricci Dark Energy

    E-Print Network [OSTI]

    Chao-Jun Feng

    2009-02-11T23:59:59.000Z

    The holographic dark energy with Ricci scalar as IR cutoff called Ricci dark energy(RDE) probes the nature of dark energy with respect to the holographic principle of quantum gravity theory. The scalar field dark energy models like quintom are often viewed as effective description of the underlying field theory of dark energy. In this letter, we assume RDE model as the underlying field theory to find how the generalized ghost condensate model(GGC) that can easily realize quintom behavior can be used to effectively describe it and reconstruct the function $h(\\phi)$ of the generalized ghost condensate model.

  13. Spurious Lyapunov Exponents in Attractor Reconstruction

    SciTech Connect (OSTI)

    Sauer, T.D. [Department of Mathematical Sciences, George Mason University, Fairfax, Virginia 22030 (United States)] [Department of Mathematical Sciences, George Mason University, Fairfax, Virginia 22030 (United States); Tempkin, J.A.; Yorke, J.A. [Department of Mathematics, University of Maryland, College Park, Maryland 20742 (United States)] [Department of Mathematics, University of Maryland, College Park, Maryland 20742 (United States); Sauer, T.D.; Yorke, J.A. [Institute of Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States)] [Institute of Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States)

    1998-11-01T23:59:59.000Z

    Lyapunov exponents, perhaps the most informative invariants of a complicated dynamical process, are also among the most difficult to determine from experimental data. In particular, when using embedding theory to build chaotic attractors in a reconstruction space, extra {open_quotes}spurious{close_quotes} Lyapunov exponents arise that are not Lyapunov exponents of the original system. The origin of these spurious exponents is discussed, and formulas for their determination in the low noise limit are given. {copyright} {ital 1998} {ital The American Physical Society}

  14. Cyclotron-based neutron source for BNCT

    SciTech Connect (OSTI)

    Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K. [Sumitomo Heavy Industries, Ltd (Japan); Tanaka, H.; Sakurai, Y.; Maruhashi, A. [Kyoto University Research Reactor Institute (Japan)

    2013-04-19T23:59:59.000Z

    Kyoto University Research Reactor Institute (KURRI) and Sumitomo Heavy Industries, Ltd. (SHI) have developed a cyclotron-based neutron source for Boron Neutron Capture Therapy (BNCT). It was installed at KURRI in Osaka prefecture. The neutron source consists of a proton cyclotron named HM-30, a beam transport system and an irradiation and treatment system. In the cyclotron, H- ions are accelerated and extracted as 30 MeV proton beams of 1 mA. The proton beams is transported to the neutron production target made by a beryllium plate. Emitted neutrons are moderated by lead, iron, aluminum and calcium fluoride. The aperture diameter of neutron collimator is in the range from 100 mm to 250 mm. The peak neutron flux in the water phantom is 1.8 Multiplication-Sign 109 neutrons/cm{sup 2}/sec at 20 mm from the surface at 1 mA proton beam. The neutron source have been stably operated for 3 years with 30 kW proton beam. Various pre-clinical tests including animal tests have been done by using the cyclotron-based neutron source with {sup 10}B-p-Borono-phenylalanine. Clinical trials of malignant brain tumors will be started in this year.

  15. accurate image reconstruction: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and computer vision Hamprecht, Fred A. 5 Accurate Dynamic FIM Estimation from List-Mode PET Data for Uniform Resolution Reconstructions1 Biology and Medicine Websites Summary:...

  16. Genome-scale reconstruction and analysis of eukaryotic metabolic networks

    E-Print Network [OSTI]

    Hurlen, Natalie Christine

    2006-01-01T23:59:59.000Z

    Reconstruction of Helicobacter pylori (iIT341 GSM/GPR): Anmetabolic model of Helicobacter pylori 26695. Journal ofinfluenzae , and Helicobacter pylori , have led to useful

  17. Optimisation of the ATLAS Track Reconstruction Software for Run-2

    E-Print Network [OSTI]

    Salzburger, Andreas; The ATLAS collaboration

    2015-01-01T23:59:59.000Z

    Track reconstruction is one of the most complex element of the reconstruction of events recorded by ATLAS from collisions delivered by the LHC. It is the most time consuming reconstruction component in high luminosity environments. The flat budget projections for computing resources for Run-2 of the LHC together with the demands of reconstructing higher pile-up collision data at rates more than double those in Run-1 (an increase from 400 Hz to 1 kHz in trigger output) have put stringent requirements on the track reconstruction software. The ATLAS experiment has performed a two year long software campaign which aimed to reduce the reconstruction rate by a factor of three to meet the resource limitations for Run-2: the majority of the changes to achieve this were improvements to the track reconstruction software. The CPU processing time of ATLAS track reconstruction was reduced by more than a factor of three during this campaign without any loss of output information of the track reconstruction. We present the ...

  18. A Fast Algorithm for Total Variation Image Reconstruction from ...

    E-Print Network [OSTI]

    2010-01-12T23:59:59.000Z

    small number of linear projections and then reconstructs it from the limited ... [29] regularization in recovering high quality image is not without a price.

  19. Review of structure representation and reconstruction on mesoscale and microscale

    SciTech Connect (OSTI)

    Li, Dongsheng

    2014-05-01T23:59:59.000Z

    Structure representation and reconstruction on mesoscale and microscale is critical in material design, advanced manufacturing and multiscale modeling. Microstructure reconstruction has been applied in different areas of materials science and technology, structural materials, energy materials, geology, hydrology, etc. This review summarizes the microstructure descriptors and formulations used to represent and algorithms to reconstruct structures at microscale and mesoscale. In the stochastic methods using correlation function, different optimization approaches have been adapted for objective function minimization. A variety of reconstruction approaches are compared in efficiency and accuracy.

  20. aspects reconstruction complications: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    better information Yanikoglu, Berrin 5 Reconstructing Images from Projections Using the Maximum-Entropy Method. Numerical Simulations of Low-Aspect Astrotomography Astrophysics...

  1. Overview of the US-Japan collaborative investigation on hydrogen isotope retention in neutron-irradiated and ion-damaged tungsten

    SciTech Connect (OSTI)

    Masashi Shimada; Y. Hatano; Y. Oya; T. Oda; M. Hara; G. Cao; M. Kobayashi; M. Sokolov; H. Watanabe; B. Tyburska; Y. Ueda; P. Calderoni

    2011-09-01T23:59:59.000Z

    Plasma-facing components (PFCs) will be exposed to 14 MeV neutrons from deuterium-tritium (D-T) fusion reactions, and tungsten, a candidate PFC for the divertor in ITER, is expected to receive a neutron dose of 0.7 displacement per atom (dpa) by the end of operation in ITER. The effect of neutron-irradiation damage has been mainly simulated using high-energy ion bombardment. While this prior database of results is quite valuable for understanding the behavior of hydrogen isotopes in PFCs, it does not encompass the full range of effects that must be considered in a practical fusion environment due to short penetration depth, damage gradient, high damage rate, and high PKA energy spectrum of the ion bombardment. In addition, neutrons change the elemental composition via transmutations, and create a high radiation environment inside PFCs, which influence the behavior of hydrogen isotope in PFCs, suggesting the utilization of fission reactors is necessary for neutron irradiation. Therefore, the effort to correlate among high-energy ions, fission neutrons, and fusion neutrons is crucial for accurately estimating tritium retention under a neutron-irradiation environment. Under the framework of the US-Japan TITAN program, tungsten samples (99.99 at. % purity from A.L.M.T. Co.) were irradiated by neutron in the High Flux Isotope Reactor (HFIR), ORNL, at 50 and 300C to 0.025, 0.3, and 1.2 dpa, and the investigation of deuterium retention in neutron-irradiation was performed in the INL Tritium Plasma Experiment (TPE), the unique high-flux linear plasma facility that can handle tritium, beryllium and activated materials. This paper reports the recent results from the comparison of ion-damaged tungsten via various ion species (2.8 MeV Fe2+, 20 MeV W2+, and 700 keV H-) with that from neutron-irradiated tungsten to identify the similarities and differences among them.

  2. Synthesize Neutron-Drip-Line-Nuclides with Free-Neutron Bose-Einstein Condensates Experimentally

    E-Print Network [OSTI]

    Bao-Guo Dong

    2014-09-22T23:59:59.000Z

    We first show a possible way to create a new type of matter, free-neutron Bose-Einstein condensate by the ultracold free-neutron-pair Bose-Einstein condensation and then determine the neutron drip line experimentally. The Bose-Einstein condensation of bosonic and fermionic atoms in atomic gases was performed experimentally and predicted theoretically early. Neutrons are similar to fermionic atoms. We found free neutrons could be cooled to ultracold neutrons with very low energy by other colder neutral atoms which are cooled by the laser. These neutrons form neutron pairs with spin zero, and then ultracold neutron-pairs form Bose-Einstein condensate. Our results demonstrate how these condensates can react with accelerated ion beams at different energy to synthesize very neutron-rich nuclides near, on or/and beyond the neutron drip line, to determine the neutron drip line and whether there are long-life nuclide or isomer islands beyond the neutron drip line experimentally. Otherwise, these experimental results will confirm our prediction that is in the whole interacting region or distance of nuclear force in all energy region from zero to infinite, Only repulsive nuclear force exists among identical nucleons and only among different nucleons exists attractive nuclear force.

  3. Electron microscopy and small angle neutron scattering study of precipitation in low alloy steel submerged-arc welds

    SciTech Connect (OSTI)

    Williams, T.J. [Rolls-Royce and Associates Ltd., Raynesway (United Kingdom); Phythian, W.J. [AEA Reactors Services, Didcot (United Kingdom)

    1996-12-31T23:59:59.000Z

    In previous studies, submerged-arc welds with a range of compositions were irradiated in test reactors over a range of dose and dose-rates. The effect of irradiation was measured by Charpy V-notch and hardness tests, and an irradiation response model was developed. In this paper the authors report the results of a combined electron microscopy and small angle neutron scattering (SANS) study on material from some of the Charpy specimens. The results have been interpreted in terms of the Russell and Brown modulus hardening model. In general they have confirmed the predictions of the irradiation response model, and shown that the copper precipitation contribution to the observed macroscopic to the observed macroscopic hardening is strongly dependent on nickel, dose and dose-rate.

  4. Workshop on neutron capture therapy

    SciTech Connect (OSTI)

    Fairchild, R.G.; Bond, V.P. (eds.)

    1986-01-01T23:59:59.000Z

    Potentially optimal conditions for Neutron Capture Therapy (NCT) may soon be in hand due to the anticipated development of band-pass filtered beams relatively free of fast neutron contaminations, and of broadly applicable biomolecules for boron transport such as porphyrins and monoclonal antibodies. Consequently, a number of groups in the US are now devoting their efforts to exploring NCT for clinical application. The purpose of this Workshop was to bring these groups together to exchange views on significant problems of mutual interest, and to assure a unified and effective approach to the solutions. Several areas of preclinical investigation were deemed to be necessary before it would be possible to initiate clinical studies. As neither the monomer nor the dimer of sulfhydryl boron hydride is unequivocally preferable at this time, studies on both compounds should be continued until one is proven superior.

  5. Monte Carlo calculation of delayed gamma dose rate in complex geometry using the concept of effective delayed gamma production cross section

    SciTech Connect (OSTI)

    Liew, S.L.; Ku, L.P. (Princeton Univ., NJ (United States). Plasma Physics Lab.)

    1991-02-01T23:59:59.000Z

    This paper reports on the delayed gamma dose rate problem formulated in terms of the effective delayed gamma production cross section. The coupled neutron-delayed gamma transport equations take the same form as the coupled neutron-prompt gamma transport equations and they can, therefore, be solved directly in the same manner. This eliminates the flux coupling step required in conventional calculations and makes it easier to handle complex, multidimensional problems, especially those that call for Monte Carlo calculations. Mathematical formulation and solution algorithms are derived. The advantages of this method in complex geometry are illustrated by its application in the Monte Carlo solution of a practical design problem.

  6. General Electric PETtrace cyclotron as a neutron source for boron neutron capture therapy 

    E-Print Network [OSTI]

    Bosko, Andrey

    2005-11-01T23:59:59.000Z

    This research investigates the use of a PETtrace cyclotron produced by General Electric (GE) as a neutron source for boron neutron capture therapy (BNCT). The GE PETtrace was chosen for this investigation because this type of cyclotron is popular...

  7. Measurement of delayed-neutron yield from {sup 237}Np fission induced by thermal neutrons

    SciTech Connect (OSTI)

    Gundorin, N. A.; Zhdanova, K. V.; Zhuchko, V. E.; Pikelner, L. B., E-mail: plb@nf.jinr.ru; Rebrova, N. V.; Salamatin, I. M.; Smirnov, V. I.; Furman, V. I. [Joint Institute for Nuclear Research (Russian Federation)

    2007-06-15T23:59:59.000Z

    The delayed-neutron yield from thermal-neutron-induced fission of the {sup 237}Np nucleus was measured using a sample periodically exposed to a pulsed neutron beam with subsequent detection of neutrons during the time intervals between pulses. The experiment was realized on an Isomer-M setup mounted in the IBR-2 pulsed reactor channel equipped with a mirror neutron guide. The setup and the experimental procedure are described, the background sources are thoroughly analyzed, and the experimental data are presented. The total delayed-neutron yield from {sup 237}Np fission induced by thermal neutrons is {nu}{sub d} = 0.0110 {+-} 0.0009. This study was performed at the Frank Laboratory of Neutron Physics (JINR, Dubna)

  8. Ion sources for sealed neutron tubes

    SciTech Connect (OSTI)

    Burns, E.J.T. [Sandia National Labs., Albuquerque, NM (United States). Neutron Tube Dept.; Bischoff, G.C. [Lockheed Martin Specialty Components, Largo, FL (United States)

    1996-11-01T23:59:59.000Z

    Fast and thermal neutron activation analysis with sealed neutron generators has been used to detect oil (oil logging), hazardous waste, fissile material, explosives, and contraband (drugs). Sealed neutron generators, used in the above applications, must be small and portable, have good electrical efficiency and long life. The ion sources used in the sealed neutron tubes require high gas utilization efficiencies or low pressure operation with high ionization efficiencies. In this paper, the authors compare a number of gas ion sources that can be used in sealed neutron tubes. The characteristics of the most popular ion source, the axial Penning discharge will be discussed as part of the zetatron neutron generator. Other sources to be discussed include the SAMIS source and RF ion source.

  9. Simultaneous reduction of radiation dose and scatter for CBCT by using collimators

    SciTech Connect (OSTI)

    Li, Tianfang; Li, Xiang; Yang, Yong; Zhang, Yongqian; Heron, Dwight E.; Huq, M. Saiful [Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15232 (United States)] [Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15232 (United States)

    2013-12-15T23:59:59.000Z

    Purpose: On-board cone-beam CT (CBCT) imaging has been widely available in radiotherapy clinic for target localization. However, the extra radiation dose from CBCT is always a concern for its frequent use. Additionally, the relatively large scatter in CBCT often degrades the image quality. By using collimators, some of the X-rays can be stopped from reaching the patient and the detectors, hence both the scatter and the patient doses are simultaneously reduced. The authors show in this work that the collimated CBCT data can be reconstructed without any noticeable artifacts for certain collimator blocking ratios and blocking patterns, and the focus of this work is to study the relationship between the image quality and these two collimator factors.Methods: A CBCT system with collimators was simulated following the typical geometry used in clinic. Different collimator designs were tested by varying the size and the number of the collimator slits, and at the same time, the ratio of transmitted beams to total beams was varied from 100% to 10%, resulting in hundreds of different simulation scenarios. Lung and pelvis phantoms created from patients CT images were used in the simulations, and an iterative reconstruction algorithm using the compressed sensing technique was adopted. The image quality was examined by root mean square errors (RMSEs) and compared with the conventional CBCT images.Results: The CBCT image quality increases as the amount of beams passing through the collimators increases, and decreases as the size of the collimator slits increases. With ultra-high resolution collimators, the RMSEs were comparable to the conventional CBCT image quality until the beam transmission rate is reduced below 25%.Conclusions: Collimators can reduce the scatters and radiation dose, however, the collimated CBCT image quality is strongly dependent on both the collimator blocking ratio and the blocking pattern. To achieve image quality comparable to the conventional CBCT, the amount of information and data format must be adequate.

  10. Aerial Neutron Detection: Neutron Signatures for Nonproliferation and Emergency Response Applications

    SciTech Connect (OSTI)

    Maurer, Richard J.; Stampahar, Thomas G.; Smith, Ethan X.; Mukhopadhyay, Sanjoy; Wolff, Ronald S.; Rourke, Timothy J.; LeDonne, Jeffrey P.; Avaro, Emanuele; Butler, D. Andre; Borders, Kevin L.; Stampahar, Jezabel; Schuck, William H.; Selfridge, Thomas L.; McKissack, Thomas M.; Duncan, William W.; Hendricks, Thane J.

    2012-10-17T23:59:59.000Z

    From 2007 to the present, the Remote Sensing Laboratory has been conducting a series of studies designed to expand our fundamental understanding of aerial neutron detection with the goal of designing an enhanced sensitivity detection system for long range neutron detection. Over 35 hours of aerial measurements in a helicopter were conducted for a variety of neutron emitters such as neutron point sources, a commercial nuclear power reactor, nuclear reactor spent fuel in dry cask storage, depleted uranium hexafluoride and depleted uranium metal. The goals of the project were to increase the detection sensitivity of our instruments such that a 5.4 × 104 neutron/second source could be detected at 100 feet above ground level at a speed of 70 knots and to enhance the long-range detection sensitivity for larger neutron sources, i.e., detection ranges above 1000 feet. In order to increase the sensitivity of aerial neutron detection instruments, it is important to understand the dynamics of the neutron background as a function of altitude. For aerial neutron detection, studies have shown that the neutron background primarily originates from above the aircraft, being produced in the upper atmosphere by galactic cosmic-ray interactions with air molecules. These interactions produce energetic neutrons and charged particles that cascade to the earth’s surface, producing additional neutrons in secondary collisions. Hence, the neutron background increases as a function of altitude which is an impediment to long-range neutron detection. In order to increase the sensitivity for long range detection, it is necessary to maintain a low neutron background as a function of altitude. Initial investigations show the variation in the neutron background can be decreased with the application of a cosmic-ray shield. The results of the studies along with a representative data set are presented.

  11. Ferromagnetism in neutron matter and its implication for the neutron star equation of state

    SciTech Connect (OSTI)

    Diener, J. P. W. [Institute of Theoretical Physics, Stellenbosch University, P.O. Box X1, Matieland, 7602 (South Africa); Scholtz, F. G. [Institute of Theoretical Physics, Stellenbosch University, P.O. Box X1, Matieland, 7602 (South Africa); National Institute for Theoretical Physics, P.O. Box X1, Matieland, 7602 (South Africa)

    2011-09-21T23:59:59.000Z

    We investigate the possible contribution of the ferromagnetic phase of neutron matter in the neutron star interior to the star's magnetic field. We introduce a relativistic, self-consistent calculation of the ferromagnetic phase in neutron matter within the context of the relativistic mean-field approximation. The presence of the ferromagnetic phase stiffens the star's equation of state which implies a larger neutron star radius compared to the non-ferromagnetic case.

  12. Neutron Generators for Spent Fuel Assay

    SciTech Connect (OSTI)

    Ludewigt, Bernhard A

    2010-12-30T23:59:59.000Z

    The Next Generation Safeguards Initiative (NGSI) of the U.S. DOE has initiated a multi-lab/university collaboration to quantify the plutonium (Pu) mass in, and detect the diversion of pins from, spent nuclear fuel (SNF) assemblies with non-destructive assay (NDA). The 14 NDA techniques being studied include several that require an external neutron source: Delayed Neutrons (DN), Differential Die-Away (DDA), Delayed Gammas (DG), and Lead Slowing-Down Spectroscopy (LSDS). This report provides a survey of currently available neutron sources and their underlying technology that may be suitable for NDA of SNF assemblies. The neutron sources considered here fall into two broad categories. The term 'neutron generator' is commonly used for sealed devices that operate at relatively low acceleration voltages of less than 150 kV. Systems that employ an acceleration structure to produce ion beam energies from hundreds of keV to several MeV, and that are pumped down to vacuum during operation, rather than being sealed units, are usually referred to as 'accelerator-driven neutron sources.' Currently available neutron sources and future options are evaluated within the parameter space of the neutron generator/source requirements as currently understood and summarized in section 2. Applicable neutron source technologies are described in section 3. Commercially available neutron generators and other source options that could be made available in the near future with some further development and customization are discussed in sections 4 and 5, respectively. The pros and cons of the various options and possible ways forward are discussed in section 6. Selection of the best approach must take a number of parameters into account including cost, size, lifetime, and power consumption, as well as neutron flux, neutron energy spectrum, and pulse structure that satisfy the requirements of the NDA instrument to be built.

  13. Information from leading neutrons at HERA

    E-Print Network [OSTI]

    V. A. Khoze; A. D. Martin; M. G. Ryskin

    2006-06-20T23:59:59.000Z

    In principle, leading neutrons produced in photoproduction and deep-inelastic scattering at HERA have the potential to determine the pion structure function, the neutron absorptive cross section and the form of the pion flux. To explore this potential we compare theoretical predictions for the x_L and p_t spectra of leading neutrons, and the Q^2 dependence of the cross section, with the existing ZEUS data.

  14. The modelling of irradiation-enhanced phosphorus segregation in neutron irradiated reactor pressure vessel submerged-arc welds

    SciTech Connect (OSTI)

    Druce, S.G.; English, C.A.; Foreman, A.J.E.; McElroy, R.J.; Vatter, I.A. [AEA Technology, Didcot (United Kingdom). Harwell Lab.; Bolton, C.J.; Buswell, J.T.; Jones, R.B. [Nuclear Electric, Berkeley (United Kingdom). Berkeley Technology Centre

    1996-12-31T23:59:59.000Z

    Recent results on neutron-irradiated RPV submerged-arc welds have revealed grain boundary segregation of phosphorus during irradiation, which may lead to intergranular fracture. However, the experimental database is insufficient to define the dependence of the process on variables such ad dose, dose-rate and temperature. This paper describes work in which two existing models of phosphorus segregation, under thermal or irradiation conditions, have been developed to obtain predictions of these dependencies. The critical parameters in the models have been adjusted to give consistency with the available reference data, and predictions have been made of the dependence of segregation on a number of variables.

  15. Neutrons used to study model vascular systems

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the endothelial cells and the supporting substrate. In what may be the first use of neutron scattering to study complex bio-medical systems under dynamic conditions, Los...

  16. Spallation Neutron Source reaches megawatt power

    ScienceCinema (OSTI)

    Dr. William F. Brinkman

    2010-01-08T23:59:59.000Z

    The Department of Energy's Spallation Neutron Source (SNS), already the world's most powerful facility for pulsed neutron scattering science, is now the first pulsed spallation neutron source to break the one-megawatt barrier. "Advances in the materials sciences are fundamental to the development of clean and sustainable energy technologies. In reaching this milestone of operating power, the Spallation Neutron Source is providing scientists with an unmatched resource for unlocking the secrets of materials at the molecular level," said Dr. William F. Brinkman, Director of DOE's Office of Science.

  17. Neutron Imaging of Advanced Engine Technologies

    Broader source: Energy.gov (indexed) [DOE]

    Science Division Hassina Z. Bilheux & Sophie Voisin Oak Ridge National Laboratory Neutron Scattering Science Division Jens Gregor University of Tennessee - Knoxville Dept....

  18. The Neutron Imaging Diagnostic at NIF

    SciTech Connect (OSTI)

    Merrill, F E; Buckles, R; Clark, D; Danly, C R; Drury, O B; Dzenitis, J M; Fatherly, V E; Fittinghoff, D N; Gallegos, R; Grim, G P; Guler, N; Loomis, E N; Lutz, S; Malone, R M; Martinson, D D; Mares, D; Morley, D J; Morgan, G L; Oertel, J A; Tregillis, I L; Volegov, P L; Weiss, P B; Wilde, C H

    2012-10-01T23:59:59.000Z

    A neutron imaging diagnostic has recently been commissioned at the National Ignition Facility (NIF). This new system is an important diagnostic tool for inertial fusion studies at the NIF for measuring the size and shape of the burning DT plasma during the ignition stage of ICF implosions. The imaging technique utilizes a pinhole neutron aperture, placed between the neutron source and a neutron detector. The detection system measures the two dimensional distribution of neutrons passing through the pinhole. This diagnostic has been designed to collect two images at two times. The long flight path for this diagnostic, 28 m, results in a chromatic separation of the neutrons, allowing the independently timed images to measure the source distribution for two neutron energies. Typically the first image measures the distribution of the 14 MeV neutrons and the second image of the 6-12 MeV neutrons. The combination of these two images has provided data on the size and shape of the burning plasma within the compressed capsule, as well as a measure of the quantity and spatial distribution of the cold fuel surrounding this core.

  19. Neutronic Characterization of the Megapie Target

    E-Print Network [OSTI]

    Stefano Panebianco; Olivier Bringer; Pavel Bokov; Sebastien Chabod; Frederic Chartier; Emmeric Dupont; Diane Dore; Xavier Ledoux; Alain Letourneau; Ludovic Oriol; Aurelien Prevost; Danas Ridikas; Jean-Christian Toussaint

    2007-10-31T23:59:59.000Z

    The MEGAPIE project is one of the key experiments towards the feasibility of Accelerator Driven Systems. On-line operation and post-irradiation analysis will provide the scientific community with unique data on the behavior of a liquid spallation target under realistic irradiation conditions. A good neutronics performance of such a target is of primary importance towards an intense neutron source, where an extended liquid metal loop requires some dedicated verifications related to the delayed neutron activity of the irradiated PbBi. In this paper we report on the experimental characterization of the MEGAPIE neutronics in terms of the prompt neutron (PN) flux inside the target and the delayed neutron (DN) flux on the top of it. For the PN measurements, a complex detector, made of 8 microscopic fission chambers, has been built and installed in the central part of the target to measure the absolute neutron flux and its spatial distribution. Moreover, integral information on the neutron energy distribution as a function of the position along the beam axis could be extracted, providing integral constraints on the neutron production models implemented in transport codes such as MCNPX. For the DN measurement, we used a standard 3He counter and we acquired data during the start-up phase of the target irradiation in order to take sufficient statistics at variable beam power. Experimental results obtained on the PN flux characteristics and their comparison with MCNPX simulations are presented, together with a preliminary analysis of the DN decay time spectrum.

  20. Compound Refractive Lenses for Thermal Neutron Applications

    SciTech Connect (OSTI)

    Gary, Charles K.

    2013-11-12T23:59:59.000Z

    This project designed and built compound refractive lenses (CRLs) that are able to focus, collimate and image using thermal neutrons. Neutrons are difficult to manipulate compared to visible light or even x rays; however, CRLs can provide a powerful tool for focusing, collimating and imaging neutrons. Previous neutron CRLs were limited to long focal lengths, small fields of view and poor resolution due to the materials available and manufacturing techniques. By demonstrating a fabrication method that can produce accurate, small features, we have already dramatically improved the focal length of thermal neutron CRLs, and the manufacture of Fresnel lens CRLs that greatly increases the collection area, and thus efficiency, of neutron CRLs. Unlike a single lens, a compound lens is a row of N lenslets that combine to produce an N-fold increase in the refraction of neutrons. While CRLs can be made from a variety of materials, we have chosen to mold Teflon lenses. Teflon has excellent neutron refraction, yet can be molded into nearly arbitrary shapes. We designed, fabricated and tested Teflon CRLs for neutrons. We demonstrated imaging at wavelengths as short as 1.26 ? with large fields of view and achieved resolution finer than 250 ?m which is better than has been previously shown. We have also determined designs for Fresnel CRLs that will greatly improve performance.

  1. LANSCE | Lujan Center | Highlights | Neutron Reflectometry (NR...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of the crystallinity of the sample (single crystal, polycrystalline, or amorphous). Neutron scattering is a unique tool to study such nanolayered composites because the...

  2. Data Analysis & Visualization | Neutron Science | ORNL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Data Analysis and Visualization As the data sets generated by the increasingly powerful neutron scattering instruments at HFIR and SNS grow ever more massive, the facilities'...

  3. Chemical and Engineering Materials | Neutron Science | ORNL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and novel engineering materials. The user community takes advantage of capabilities of neutron scattering for measurements over wide ranges of experimental and operating...

  4. Plutonium Detection with Straw Neutron Detectors

    SciTech Connect (OSTI)

    Mukhopadhyay, Sanjoy; Maurer, Richard; Guss, Paul

    2014-03-27T23:59:59.000Z

    A kilogram of weapons grade plutonium gives off about 56,000 neutrons per second of which 55,000 neutrons come from spontaneous fission of 240Pu (~6% by weight of the total plutonium). Actually, all even numbered isotopes (238Pu, 240Pu, and 242Pu) produce copious spontaneous fission neutrons. These neutrons induce fission in the surrounding fissile 239Pu with an approximate multiplication of a factor of ~1.9. This multiplication depends on the shape of the fissile materials and the surrounding material. These neutrons (typically of energy 2 MeV and air scattering mean free path >100 meters) can be detected 100 meters away from the source by vehicle-portable neutron detectors. [1] In our current studies on neutron detection techniques, without using 3He gas proportional counters, we designed and developed a portable high-efficiency neutron multiplicity counter using 10B-coated thin tubes called straws. The detector was designed to perform like commercially available fission meters (manufactured by Ortec Corp.) except instead of using 3He gas as a neutron conversion material, we used a thin coating of 10B.

  5. Neutron Data Analysis & Visualization | More Science | ORNL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Data Analysis and Visualization As the data sets generated by the increasingly powerful neutron scattering instruments at HFIR and SNS grow ever more massive, the facilities'...

  6. Ultracold Neutrons at Los Alamos National Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    with the decay electrons. UCNb UCNb measures the potential distortion of the neutron beta-decay energy spectrum due to physics beyond the Standard Model. Nab The Nab...

  7. Radiation Leukemogenesis at Low Dose Rates

    SciTech Connect (OSTI)

    Weil, Michael; Ullrich, Robert

    2013-09-25T23:59:59.000Z

    The major goals of this program were to study the efficacy of low dose rate radiation exposures for the induction of acute myeloid leukemia (AML) and to characterize the leukemias that are caused by radiation exposures at low dose rate. An irradiator facility was designed and constructed that allows large numbers of mice to be irradiated at low dose rates for protracted periods (up to their life span). To the best of our knowledge this facility is unique in the US and it was subsequently used to study radioprotectors being developed for radiological defense (PLoS One. 7(3), e33044, 2012) and is currently being used to study the role of genetic background in susceptibility to radiation-induced lung cancer. One result of the irradiation was expected; low dose rate exposures are ineffective in inducing AML. However, another result was completely unexpected; the irradiated mice had a very high incidence of hepatocellular carcinoma (HCC), approximately 50%. It was unexpected because acute exposures are ineffective in increasing HCC incidence above background. This is a potential important finding for setting exposure limits because it supports the concept of an 'inverse dose rate effect' for some tumor types. That is, for the development of some tumor types low dose rate exposures carry greater risks than acute exposures.

  8. absorbed dose calculation: Topics by E-print Network

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    2010-01-01 4 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  9. absorbed dose measurements: Topics by E-print Network

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    2013-01-01 3 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  10. air dose absorbed: Topics by E-print Network

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    2009-01-01 3 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  11. absorbed dose distribution: Topics by E-print Network

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    2010-01-01 3 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  12. absorbed dose measurement: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2013-01-01 3 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  13. absorbed dose determination: Topics by E-print Network

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    2012-06-07 5 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  14. absorbed dose effective: Topics by E-print Network

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    2010-01-01 2 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  15. absorbed dose standard: Topics by E-print Network

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    2010-01-01 4 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  16. absorbed doses distribution: Topics by E-print Network

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    2010-01-01 3 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  17. absorbed dose distributions: Topics by E-print Network

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    2010-01-01 3 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  18. absorbed dose rate: Topics by E-print Network

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    2010-01-01 3 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  19. absorbed dose determinations: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2012-06-07 5 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...

  20. absorbed dose calculations: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2010-01-01 4 Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny Biology and Medicine Websites Summary: Absorbed dose in target cell nuclei and...