Progress report on neutron scattering research. April 1, 2002 - March 31, 2003

International Nuclear Information System (INIS)

Koizumi, Satoshi; Matsuda, Masaaki; Kurihara, Kazuo

2004-03-01

This issue summarizes research progress in neutron scattering at Japan Atomic Energy Research Institute (JAERI) by utilizing the research reactor JRR-3 during the period between April 1, 2002 and March 31, 2003. (author)

Neutron-induced mutation experiments. Progress report, March 1, 1976--February 28, 1977

International Nuclear Information System (INIS)

Abrahamson, S.

1976-11-01

Results are from studies of experiments in Drosophila on the relative mutagenic effectiveness of neutrons of different energies employing X-linked recessive lethal and specific locus mutation tests. The energies and doses employed to data are .43 MeV (500, 1000, and 1500 R, in progress), .68 MeV (250, 500, 1000, and 1500 R), 2 and 6 MeV (250 and 500 R), and 15 MeV (250, 500, 1000, 1500 and 3000 R). .68 MeV neutrons appear to have an RBE between 3.3 to 4.5, 15 MeV neutrons an RBE between 1.9 to 2.2, and 2 and 6 MeV neutrons RBE's of intermediate values. The data for both .68 and 15 MeV neutrons do not yet differentiate between a linear and quadratic dose/frequency response curve for the doses studied. The specific locus mutation data also indicate the highest RBE for .68 MeV, followed by 2 and 6 MeV respectively

Progress report on neutron scattering research. April 1, 1999 - March 31, 2000

Energy Technology Data Exchange (ETDEWEB)

Fujiwara, Satoru; Aizawa, Kazuya; Katano, Susumu (eds.) [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2001-03-01

This issue summarizes research progress in neutron scattering at Japan Atomic Energy Research Institute (JAERI) by utilizing the research reactor (JRR-3M) during the period between April 1, 1999 and March 31, 2000. (author)

Progress report on neutron scattering research. April 1, 2000 - March 31, 2001

International Nuclear Information System (INIS)

Aizawa, Kazuya; Katano, Susumu; Koizumi, Satoshi

2002-03-01

This issue summarizes research progress in neutron scattering at Japan Atomic Energy Research Institute (JAERI) by utilizing the research reactor (JRR-3M) during the period between April 1, 2000 and March 31, 2001. (author)

Progress report on neutron scattering research. April 1, 2001 - March 31, 2002

Energy Technology Data Exchange (ETDEWEB)

Katano, Susumu; Koizumi, Satoshi; Matsuda, Masaaki (eds.) [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2002-11-01

This issue summarizes research progress in neutron scattering at Japan Atomic Energy Research Institute (JAERI) by utilizing the research reactor JRR-3M during the period between April 1, 2001 and March 31, 2002. (author)

Progress report on neutron scattering research (April 1, 1998 - March 31, 1999)

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Jun-ichi; Fujiwara, Satoru; Aizawa, Kazuya [eds.] [Advanced Science Research Center (Tokai Site), Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan)

2000-03-01

The present issue summarizes research progress in neutron scattering at Japan Atomic Energy Research Institute (JAERI) by utilizing the research reactor (JRR-3M) during the period between April 1, 1998 and March 31, 1999. (author)

Fast neutron dosimetry. Progress report, 30 August 1992--1 September 1993

Energy Technology Data Exchange (ETDEWEB)

DeLuca, P.M. Jr.; Pearson, D.W.

1993-12-01

Research concentrated on three major areas during the last twelve months: (1) investigations of energy fluence and absorbed dose measurements using crystalline and hot pressed TLD materials exposes to ultrasoft beams of photons, (2) fast neutron kerma factor measurements for several important elements as well as NE-213 scintillation material response function determinations at the intense ``white`` source available at the WNR facility at LAMPF, and (3) kerma factor ratio determinations for carbon and oxygen to A-150 tissue equivalent plastic at the clinical fast neutron radiation facility at Harper Hospital, Detroit, MI. Progress summary reports of these efforts are given in this report.

Progress in study of a medical reactor for boron neutron capture therapy

International Nuclear Information System (INIS)

Sasaki, Makoto; Hirota, Jitsuya; Tamao, Shigeo; Kanda, Keiji; Mishima, Yutaka.

1993-01-01

A design study of a medical reactor for Boron Neutron Capture Therapy has made progress. Main specifications of the reactor are as follows; thermal power of 2 MW, water cooling by natural convection, semitight core of hexagonal lattice, UO 2 fuel rod of 9.5 mm diameter and no refueling in the reactor-life. Three horizontal and one vertical neutron beam holes are to be provided for simultaneous treatments by thermal and epithermal neutrons and for further biomedical research. The design objectives for the beam holes are to deliver the therapeutic doses in a modest time (30 to 60 min) with minimal fast neutron and gamma contaminants. The n-γ coupling Sn transport calculations have been carried out using n-21 and γ-9 group cross sections on 2-dim. practical models. The calculated results indicate that the design objectives will be achievable even if the thermal power of the reactor is reduced to 1 MW. (author)

Progress report on neutron scattering research (April 1, 1997 - March 31, 1998)

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Jun-ichi; Fujiwara, Satoru; Aizawa, Kazuya [eds.

1999-02-01

The present issue summarizes research progress in neutron scattering at Japan Atomic Energy Research Institute (JAERI) by utilizing the research reactor (JRR-3M) during the period between April 1, 1997 and March 31, 1998. The 76 papers are indexed individually. (J.P.N.)

Neutron scattering studies in the actinide region. Progress report, August 1, 1991--July 31, 1994

International Nuclear Information System (INIS)

Kegel, G.H.R.; Egan, J.J.

1994-09-01

During the period August 1, 1991 to July 31, 1994 the authors report progress on the following: (a) prompt fission neutron energy spectra for 235 U and 239 Pu; (b) two-parameter measurement of nuclear lifetimes; (c) 'black' neutron detector; (d) data reduction techniques for neutron scattering experiments; (e) elastic and inelastic neutron scattering studies in 197 Au; (f) elastic and inelastic neutron scattering studies in 239 Pu; (g) neutron induced defects in silicon dioxide MOS structures; (h) response of a 235 U fission chamber near reaction thresholds; (i) efficiency calibration of a liquid scintillation detector using the WNR facility at LAMPF; (j) prompt fission neutron energy spectrum measurements below the incident neutron energy; (k) multi-parameter data acquisition system; (l) accelerator improvements; (m) non-DOE supported research. Eight Ph.D. dissertations and two M.S. theses were completed during the report period. Publications consisted of 6 journal articles, 10 conference proceedings, and 19 abstracts of presentations at scientific meetings. One invited talk was given

Progress report on neutron scattering research (April 1, 1996 - March 31, 1997)

Energy Technology Data Exchange (ETDEWEB)

Ishii, Yoshinobu; Suzuki, Jun-ichi; Fujiwara, Satoru [eds.

1997-10-01

This issue summarizes research progress in neutron scattering at Japan Atomic Energy Research Institute (JAERI) by utilizing the research reactor (JRR-3M) mainly during the period between April 1, 1996 and March 31, 1997. The 57 of the presented papers are indexed individually. (J.P.N.)

Computational methods for the nuclear and neutron matter problems. Progress report

International Nuclear Information System (INIS)

Kalos, M.H.

1979-01-01

A brief report is given of progress on the development of Monte Carlo methods for the treatment of both simplified and realistic models of extensive neutron and nuclear matter and, eventually, of finite nuclei. A wide class of algorithms that may allow the efficient sampling of the integrands required in calculating the energy expectations with useful trial wave functions was devised

Progress of JAERI neutron science project

International Nuclear Information System (INIS)

Oyama, Yukio

1999-01-01

Neutron Science Project was started at Japan Atomic Energy Research Institute since 1996 for promoting futuristic basic science and nuclear technology utilizing neutrons. For this purpose, research and developments of intense proton accelerator and spallation neutron target were initiated. The present paper describes the current status of such research and developments. (author)

Progress in the neutronic core conversion (HEU-LEU) analysis of Ghana research reactor-1.

Energy Technology Data Exchange (ETDEWEB)

Anim-Sampong, S.; Maakuu, B. T.; Akaho, E. H. K.; Andam, A.; Liaw, J. J. R.; Matos, J. E.; Nuclear Engineering Division; Ghana Atomic Energy Commission; Kwame Nkrumah Univ. of Science and Technology

2006-01-01

The Ghana Research Reactor-1 (GHARR-1) is a commercial version of the Miniature Neutron Source Reactor (MNSR) and has operated at different power levels since its commissioning in March 1995. As required for all nuclear reactors, neutronic and thermal hydraulic analysis are being performed for the HEU-LEU core conversion studies of the Ghana Research Reactor-1 (GHARR-1) facility, which is a commercial version of the Miniature Neutron Source Reactor (MNSR). Stochastic Monte Carlo particle transport methods and tools (MCNP4c/MCNP5) were used to fine-tune a previously developed 3-D MCNP model of the GHARR-1 facility and perform neutronic analysis of the 90.2% HEU reference and candidate LEU (UO{sub 2}, U{sub 3}Si{sub 2}, U-9Mo) fresh cores with varying enrichments from 12.6%-19.75%. In this paper, the results of the progress made in the Monte Carlo neutronic analysis of the HEU reference and candidate LEU fuels are presented. In particular, a comparative performance assessment of the LEU with respect to neutron flux variations in the fission chamber and experimental irradiation channels are highlighted.

Intense Pulsed Neutron Source: Progress report 1991--1996. 15. Anniversary edition -- Volume 2

International Nuclear Information System (INIS)

1996-01-01

The 15th Anniversary Edition of the IPNS Progress Report is being published in recognition of the Intense Pulsed Neutron Source's first 15 years of successful operation as a user facility. To emphasize the importance of this milestone, the author shave made the design and organization of the report significantly different from previous IPNS Progress Reports. This report consists of two volumes. For Volume 1, authors were asked to prepare articles that highlighted recent scientific accomplishments at IPNS, from 1991 to present; to focus on and illustrate the scientific advances achieved through the unique capabilities of neutron studies performed by IPNS users; to report on specific activities or results from an instrument; or to focus on a body of work encompassing different neutron-scattering techniques. Articles were also included on the accelerator system, instrumentation, computing, target, and moderators. A list of published and ''in press' articles in journals, books, and conference proceedings, resulting from work done at IPNS since 1991, was compiled. This list is arranged alphabetically according to first author. Publication references in the articles are listed by last name of first author and year of publication. The IPNS experimental reports received since 1991 are compiled in Volume 2. Experimental reports referenced in the articles are listed by last name of first author, instrument designation, and experiment number

Intense Pulsed Neutron Source: Progress report 1991--1996. 15. Anniversary edition -- Volume 1

International Nuclear Information System (INIS)

Marzec, B.

1996-01-01

The 15th Anniversary Edition of the IPNS Progress Report is being published in recognition of the Intense Pulsed Neutron Source's first 15 years of successful operation as a user facility. To emphasize the importance of this milestone, the authors have made the design and organization of the report significantly different from previous IPNS Progress Reports. This report consists of two volumes. For Volume 1, authors were asked to prepare articles that highlighted recent scientific accomplishments at IPNS, from 1991 to present; to focus on and illustrate the scientific advances achieved through the unique capabilities of neutron studies performed by IPNS users; to report on specific activities or results from an instrument; or to focus on a body of work encompassing different neutron-scattering techniques. Articles were also included on the accelerator system, instrumentation, computing, target, and moderators. A list of published and ''in press' articles in journals, books, and conference proceedings, resulting from work done at IPNS since 1991, was compiled. This list is arranged alphabetically according to first author. Publication references in the articles are listed by last name of first author and year of publication. The IPNS experimental reports received since 1991 are compiled in Volume 2. Experimental reports referenced in the articles are listed by last name of first author, instrument designation, and experiment number

Intense Pulsed Neutron Source: Progress report 1991--1996. 15. Anniversary edition -- Volume 1

Energy Technology Data Exchange (ETDEWEB)

Marzec, B. [ed.

1996-05-01

The 15th Anniversary Edition of the IPNS Progress Report is being published in recognition of the Intense Pulsed Neutron Source`s first 15 years of successful operation as a user facility. To emphasize the importance of this milestone, the authors have made the design and organization of the report significantly different from previous IPNS Progress Reports. This report consists of two volumes. For Volume 1, authors were asked to prepare articles that highlighted recent scientific accomplishments at IPNS, from 1991 to present; to focus on and illustrate the scientific advances achieved through the unique capabilities of neutron studies performed by IPNS users; to report on specific activities or results from an instrument; or to focus on a body of work encompassing different neutron-scattering techniques. Articles were also included on the accelerator system, instrumentation, computing, target, and moderators. A list of published and ``in press` articles in journals, books, and conference proceedings, resulting from work done at IPNS since 1991, was compiled. This list is arranged alphabetically according to first author. Publication references in the articles are listed by last name of first author and year of publication. The IPNS experimental reports received since 1991 are compiled in Volume 2. Experimental reports referenced in the articles are listed by last name of first author, instrument designation, and experiment number.

Intense Pulsed Neutron Source: Progress report 1991--1996. 15. Anniversary edition -- Volume 2

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-05-01

The 15th Anniversary Edition of the IPNS Progress Report is being published in recognition of the Intense Pulsed Neutron Source`s first 15 years of successful operation as a user facility. To emphasize the importance of this milestone, the author shave made the design and organization of the report significantly different from previous IPNS Progress Reports. This report consists of two volumes. For Volume 1, authors were asked to prepare articles that highlighted recent scientific accomplishments at IPNS, from 1991 to present; to focus on and illustrate the scientific advances achieved through the unique capabilities of neutron studies performed by IPNS users; to report on specific activities or results from an instrument; or to focus on a body of work encompassing different neutron-scattering techniques. Articles were also included on the accelerator system, instrumentation, computing, target, and moderators. A list of published and ``in press` articles in journals, books, and conference proceedings, resulting from work done at IPNS since 1991, was compiled. This list is arranged alphabetically according to first author. Publication references in the articles are listed by last name of first author and year of publication. The IPNS experimental reports received since 1991 are compiled in Volume 2. Experimental reports referenced in the articles are listed by last name of first author, instrument designation, and experiment number.

2010 Neutron Review: ORNL Neutron Sciences Progress Report

International Nuclear Information System (INIS)

Bardoel, Agatha A.; Counce, Deborah Melinda; Ekkebus, Allen E.; Horak, Charlie M.; Nagler, Stephen E.; Kszos, Lynn A.

2011-01-01

During 2010, the Neutron Sciences Directorate focused on producing world-class science, while supporting the needs of the scientific community. As the instrument, sample environment, and data analysis tools at High Flux Isotope Reactor (HFIR ) and Spallation Neutron Source (SNS) have grown over the last year, so has promising neutron scattering research. This was an exciting year in science, technology, and operations. Some topics discussed are: (1) HFIR and SNS Experiments Take Gordon Battelle Awards for Scientific Discovery - Battelle Memorial Institute presented the inaugural Gordon Battelle Prizes for scientific discovery and technology impact in 2010. Battelle awards the prizes to recognize the most significant advancements at national laboratories that it manages or co-manages. (2) Discovery of Element 117 - As part of an international team of scientists from Russia and the United States, HFIR staff played a pivotal role in the discovery by generating the berkelium used to produce the new element. A total of six atoms of ''ununseptium'' were detected in a two-year campaign employing HFIR and the Radiochemical Engineering Development Center at Oak Ridge National Laboratory (ORNL) and the heavy-ion accelerator capabilities at the Joint Institute for Nuclear Research in Dubna, Russia. The discovery of the new element expands the understanding of the properties of nuclei at extreme numbers of protons and neutrons. The production of a new element and observation of 11 new heaviest isotopes demonstrate the increased stability of super-heavy elements with increasing neutron numbers and provide the strongest evidence to date for the existence of an island of enhanced stability for super-heavy elements. (3) Studies of Iron-Based High-Temperature Superconductors - ORNL applied its distinctive capabilities in neutron scattering, chemistry, physics, and computation to detailed studies of the magnetic excitations of iron-based superconductors (iron pnictides and

2010 Neutron Review: ORNL Neutron Sciences Progress Report

Energy Technology Data Exchange (ETDEWEB)

Bardoel, Agatha A [ORNL; Counce, Deborah M [ORNL; Ekkebus, Allen E [ORNL; Horak, Charlie M [ORNL; Nagler, Stephen E [ORNL; Kszos, Lynn A [ORNL

2011-06-01

During 2010, the Neutron Sciences Directorate focused on producing world-class science, while supporting the needs of the scientific community. As the instrument, sample environment, and data analysis tools at High Flux Isotope Reactor (HFIR ) and Spallation Neutron Source (SNS) have grown over the last year, so has promising neutron scattering research. This was an exciting year in science, technology, and operations. Some topics discussed are: (1) HFIR and SNS Experiments Take Gordon Battelle Awards for Scientific Discovery - Battelle Memorial Institute presented the inaugural Gordon Battelle Prizes for scientific discovery and technology impact in 2010. Battelle awards the prizes to recognize the most significant advancements at national laboratories that it manages or co-manages. (2) Discovery of Element 117 - As part of an international team of scientists from Russia and the United States, HFIR staff played a pivotal role in the discovery by generating the berkelium used to produce the new element. A total of six atoms of ''ununseptium'' were detected in a two-year campaign employing HFIR and the Radiochemical Engineering Development Center at Oak Ridge National Laboratory (ORNL) and the heavy-ion accelerator capabilities at the Joint Institute for Nuclear Research in Dubna, Russia. The discovery of the new element expands the understanding of the properties of nuclei at extreme numbers of protons and neutrons. The production of a new element and observation of 11 new heaviest isotopes demonstrate the increased stability of super-heavy elements with increasing neutron numbers and provide the strongest evidence to date for the existence of an island of enhanced stability for super-heavy elements. (3) Studies of Iron-Based High-Temperature Superconductors - ORNL applied its distinctive capabilities in neutron scattering, chemistry, physics, and computation to detailed studies of the magnetic excitations of iron-based superconductors (iron

Neutron-induced mutation experiments. Progress report, March 1, 1977--February 28, 1978

International Nuclear Information System (INIS)

Abrahamson, S.

1977-11-01

Experiments have been carried out to study the relative mutagenic effectiveness for Drosophila female germ cells of neutrons of different energies employing X-linked recessive lethal and specific locus mutation tests. The energies and doses employed to date to study X-linked lethals are 0.43 MeV (500, 1000, 1500, 1900 R (in progress)), 0.68 MeV (250, 500, 1000, 1500 R), 2 MeV (250, 500, 1000, 1500, 2000 R), 6 MeV (250, 500, 1500, 3000 R) and 15 MeV (250, 500, 1000, 1500, 3000 R). 0.43-MeV neutrons appear to have an RBE in the range 1.9 to 4.7, 0.68 MeV 2.8 to 4.3, 2 MeV (incomplete data), 6 MeV 1.7 to 3.2, and 15 MeV 1.7 to 2.2. The data for 0.43-MeV and 0.68-MeV neutrons do not yet differentiate between a linear and a quadratic dose/frequency response curve for the doses studied, but suggest a quadratic relationship. The data for 2, 6 and 15 MeV are inconclusive. The specific locus mutation data indicate the highest RBE for 0.68-MeV neutrons, followed by 2 and 6 MeV, respectively

Design progress of cryogenic hydrogen system for China Spallation Neutron Source

Energy Technology Data Exchange (ETDEWEB)

Wang, G. P.; Zhang, Y.; Xiao, J.; He, C. C.; Ding, M. Y.; Wang, Y. Q.; Li, N.; He, K. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P.R. (China)

2014-01-29

China Spallation Neutron Source (CSNS) is a large proton accelerator research facility with 100 kW beam power. Construction started in October 2011 and is expected to last 6.5 years. The cryogenic hydrogen circulation is cooled by a helium refrigerator with cooling capacity of 2200 W at 20 K and provides supercritical hydrogen to neutron moderating system. Important progresses of CSNS cryogenic system were concluded as follows. Firstly, process design of cryogenic system has been completed including helium refrigerator, hydrogen loop, gas distribution, and safety interlock. Secondly, an accumulator prototype was designed to mitigate pressure fluctuation caused by dynamic heat load from neutron moderation. Performance test of the accumulator has been carried out at room and liquid nitrogen temperature. Results show the accumulator with welding bellows regulates hydrogen pressure well. Parameters of key equipment have been identified. The contract for the helium refrigerator has been signed. Mechanical design of the hydrogen cold box has been completed, and the hydrogen pump, ortho-para hydrogen convertor, helium-hydrogen heat exchanger, hydrogen heater, and cryogenic valves are in procurement. Finally, Hydrogen safety interlock has been finished as well, including the logic of gas distribution, vacuum, hydrogen leakage and ventilation. Generally, design and construction of CSNS cryogenic system is conducted as expected.

Progress report on neutron scattering at JAERI

Energy Technology Data Exchange (ETDEWEB)

Morii, Yukio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1998-10-01

In the first half of fiscal year 1997, JRR-3M was operated for 97 days followed by a long term shut down for its annual maintenance. Three days were lost out of 100 scheduled operation days, due to a trouble in irradiation facility. Neutron scattering research activities at the JRR-3M have been extended from that of fiscal year 1996. In the Research Group for Quantum Condensed Matter System, experimental study under high pressures, low temperatures and high fields as well as coupling of these conditions were planned to find new quantum condensed matter systems. And, obtained experimental results were immediately provided to theorists for their investigations. In cooperation with new group, Research Group for Neutron Scattering of Strongly Correlated Electron Systems and Research Group for Neutron Scattering at Ultralow Temperatures were carrying neutron scattering experiments at JRR-3M. Research Group for Neutron Crystallography in Biology had opened a way for investigating biomatter neutron diffraction research with high experimental accuracy by growing a millimeter-class large single crystal. In fiscal year 1997, 39 research projects were conducted by these four groups and other staffs in JAERI, 27 projects collaborated with university researchers and 3 projects collaborated with private enterprises were also conducted as complementary researches. 2117 days of machine times were requested to use 8 neutron scattering instruments this year, which corresponded to 1.51 times larger than those planned at its beginning. (G.K.)

Neutronics of pulsed spallation neutron sources

CERN Document Server

Watanabe, N

2003-01-01

Various topics and issues on the neutronics of pulsed spallation neutron sources, mainly for neutron scattering experiments, are reviewed to give a wide circle of readers a better understanding of these sources in order to achieve a high neutronic performance. Starting from what neutrons are needed, what the spallation reaction is and how to produce slow-neutrons more efficiently, the outline of the target and moderator neutronics are explained. Various efforts with some new concepts or ideas have already been devoted to obtaining the highest possible slow-neutron intensity with desired pulse characteristics. This paper also reviews the recent progress of such efforts, mainly focused on moderator neutronics, since moderators are the final devices of a neutron source, which determine the source performance. Various governing parameters for neutron-pulse characteristics such as material issues, geometrical parameters (shape and dimensions), the target-moderator coupling scheme, the ortho-para-hydrogen ratio, po...

Neutron matter, symmetry energy and neutron stars

Energy Technology Data Exchange (ETDEWEB)

Stefano, Gandolfi [Los Alamos National Laboratory (LANL); Steiner, Andrew W [ORNL

2016-01-01

Recent progress in quantum Monte Carlo with modern nucleon-nucleon interactions have enabled the successful description of properties of light nuclei and neutron-rich matter. Of particular interest is the nuclear symmetry energy, the energy cost of creating an isospin asymmetry, and its connection to the structure of neutron stars. Combining these advances with recent observations of neutron star masses and radii gives insight into the equation of state of neutron-rich matter near and above the saturation density. In particular, neutron star radius measurements constrain the derivative of the symmetry energy.

Neutronics of pulsed spallation neutron sources

International Nuclear Information System (INIS)

Watanabe, Noboru

2003-01-01

Various topics and issues on the neutronics of pulsed spallation neutron sources, mainly for neutron scattering experiments, are reviewed to give a wide circle of readers a better understanding of these sources in order to achieve a high neutronic performance. Starting from what neutrons are needed, what the spallation reaction is and how to produce slow-neutrons more efficiently, the outline of the target and moderator neutronics are explained. Various efforts with some new concepts or ideas have already been devoted to obtaining the highest possible slow-neutron intensity with desired pulse characteristics. This paper also reviews the recent progress of such efforts, mainly focused on moderator neutronics, since moderators are the final devices of a neutron source, which determine the source performance. Various governing parameters for neutron-pulse characteristics such as material issues, geometrical parameters (shape and dimensions), the target-moderator coupling scheme, the ortho-para-hydrogen ratio, poisoning, etc are discussed, aiming at a high performance pulsed spallation source

Neutron Decay with PERC: a Progress Report

International Nuclear Information System (INIS)

Konrad, G; Abele, H; Erhart, J; Fillunger, H; Gösselsberger, C; Horvath, M; Jericha, E; Klauser, C; Maix, R K; Nowak, S; Sauerzopf, C; Beck, M; Heil, W; Drescher, C; Dubbers, D; Märkisch, B; Mest, H; Rebrova, N; Roick, C; Klenke, J

2012-01-01

The PERC collaboration will perform high-precision measurements of angular correlations in neutron beta decay at the beam facility MEPHISTO of the Forschungs-Neutronenquelle Heinz Maier-Leibnitz in Munich, Germany. The new beam station PERC, a clean, bright, and versatile source of neutron decay products, is designed to improve the sensitivity of neutron decay studies by one order of magnitude. The charged decay products are collected by a strong longitudinal magnetic field directly from inside a neutron guide. This combination provides the highest phase space density of decay products. A magnetic mirror serves to perform precise cuts in phase space, reducing related systematic errors. The new instrument PERC is under development by an international collaboration. The physics motivation, sensitivity, and applications of PERC as well as the status of the design and preliminary results on uncertainties in proton spectroscopy are presented in this paper.

Progress report: determinations of the neutron-neutron scattering length ann from kinematically incomplete neutron-deuteron breakup data revisited

International Nuclear Information System (INIS)

Tornow, W.; Braun, R.T.; Witala, H.

1996-01-01

We review published analyses of the final-state-interaction enhancement observed in proton energy distributions obtained from kinematically incomplete neutron-deuteron breakup experiments. We compare the results derived from these analyses for the neutron-neutron scattering length, a nn with our results based on a rigorous treatment of the three-nucleon Faddeev equations in conjunction with the use of realistic nucleon-nucleon potentials. Our values for a nn deviate outside the quoted uncertainties from the ones obtained in the previous analyses where simplified nucleon-nucleon interaction models were employed. In contrast to the previous determinations, the present results for a nn are in clear disagreement with the values for a nn based on π - -deuteron capture experiments. Unless inconsistencies in the experimental neutron-deuteron breakup data at low energies can be resolved and the influence of possible three-nucleon-force effects can be reliably determined, we recommend that one not resort to the kinematically incomplete neutron-deuteron breakup reaction as a tool for determining a quantity as important for nuclear and particle physics as is the neutron-neutron scattering length a nn . (author)

Kinetic theory of neutron gases. Progress report, October 1, 1974--June 30, 1975

International Nuclear Information System (INIS)

Goldstein, H.; Cacuci, D.; Ku, L.P.; Ostrow, S.; Peng, W.

1975-01-01

Interim progress reports are presented on four investigations involving the transport of fast neutrons. The common theme tying together the four research projects is the manner in which details of microscopic cross sections affect the macroscopic transport behavior of neutron gases in material media. In the first, the classic problem of transport and slowing down in a non-hydrogenous medium with constant cross section is being reexamined, using Case's method of singular eigenfunctions. Both the asymptotic limit derived by Wick and the age-theory extreme have been recovered, and higher order corrections to these are being derived. Semi-numerical techniques have been developed which should permit calculation of the flux over wide ranges of distance and lethargy. The second investigation is the study of the effects of square-well minima in otherwise constant cross sections. A specialized moments-method code has been developed for the purpose, which gives the flux as far out as 80 to 100 mfp from the source. A simple but highly accurate model has been developed to include the effects of the minima, and it is now feasible to predict under what conditions a given minimum will significantly affect the penetration. In the third study Monte Carlo has been used to obtain the characteristics of neutron histories penetrating to various distances and energies in iron. The role of such cross section phenomena as inelastic scattering and cross section minima is being elucidated. In the last investigation, the discrete energy S/sub N/ method is being applied to various transport problems difficult of access by other methods. For example, an examination is under way of the dependence of fast-neutron albedo on the form of representation of the scattered neutron distribution and on the fine structure of the cross section. (U.S.)

Intense Pulsed Neutron Source progress report for 1991

International Nuclear Information System (INIS)

1991-01-01

The IPNS Progress Report 10th Anniversary Edition is being published in recognition of the first ten years of successful IPNS operation. To emphasize the significance of this milestone, we wanted this report to stand apart from the previous IPNS Progress Reports, and the best way to do this, we thought, was to make the design and organization of the report significantly different. In their articles, authors were asked to emphasize not only advances made since IPNS began operating but also the groundwork that was laid at its predecessor facilities - Argonne's ZING-P and ZING-P' prototype pulsed neutron sources and CP-5 reactor. Each article stands as a separate chapter in the report, since each represents a particular instrument or class of instruments, system, technique, or area of research. In some cases, contributions were similar to review articles in scientific journals, complete with extensive lists of references. Ten-year cumulative lists of members of IPNS committees and of scientists who have visited or done experiments at IPNS were assembled. A list of published and ''in press'' articles in journals, books, and conference proceedings, resulting from work done at IPNS during the past ten years, was compiled. And archival photographs of people and activities during the ten-year history of IPNS were located and were used liberally throughout the report. The titles of the chapters in this report are: accelerator; computer; radiation effects; powder; stress; single crystal; superconductivity; amorphous; small angle; reflection; quasielastic; inelastic; inelastic magnetic; deep inelastic; user program; the future; and publications

Intense Pulsed Neutron Source progress report for 1991

Energy Technology Data Exchange (ETDEWEB)

1991-12-31

The IPNS Progress Report 10th Anniversary Edition is being published in recognition of the first ten years of successful IPNS operation. To emphasize the significance of this milestone, we wanted this report to stand apart from the previous IPNS Progress Reports, and the best way to do this, we thought, was to make the design and organization of the report significantly different. In their articles, authors were asked to emphasize not only advances made since IPNS began operating but also the groundwork that was laid at its predecessor facilities - Argonne`s ZING-P and ZING-P` prototype pulsed neutron sources and CP-5 reactor. Each article stands as a separate chapter in the report, since each represents a particular instrument or class of instruments, system, technique, or area of research. In some cases, contributions were similar to review articles in scientific journals, complete with extensive lists of references. Ten-year cumulative lists of members of IPNS committees and of scientists who have visited or done experiments at IPNS were assembled. A list of published and ``in press`` articles in journals, books, and conference proceedings, resulting from work done at IPNS during the past ten years, was compiled. And archival photographs of people and activities during the ten-year history of IPNS were located and were used liberally throughout the report. The titles of the chapters in this report are: accelerator; computer; radiation effects; powder; stress; single crystal; superconductivity; amorphous; small angle; reflection; quasielastic; inelastic; inelastic magnetic; deep inelastic; user program; the future; and publications.

Advanced Neutron Source (ANS) Project progress report

International Nuclear Information System (INIS)

McBee, M.R.; Chance, C.M.

1990-04-01

This report discusses the following topics on the advanced neutron source: quality assurance (QA) program; reactor core development; fuel element specification; corrosion loop tests and analyses; thermal-hydraulic loop tests; reactor control concepts; critical and subcritical experiments; material data, structural tests, and analysis; cold source development; beam tube, guide, and instrument development; hot source development; neutron transport and shielding; I ampersand C research and development; facility concepts; design; and safety

Next generation neutron scattering at Neutron Science Center project in JAERI

International Nuclear Information System (INIS)

Yamada, Yasusada; Watanabe, Noboru; Niimura, Nobuo; Morii, Yukio; Katano, Susumu; Aizawa, Kazuya; Suzuki, Jun-ichi; Koizumi, Satoshi; Osakabe, Toyotaka.

1997-01-01

Japan Atomic Energy Research Institute (JAERI) has promoted neutron scattering researches by means of research reactors in Tokai Research Establishment, and proposes 'Neutron Science Research Center' to develop the future prospect of the Tokai Research Establishment. The scientific fields which will be expected to progress by the neutron scattering experiments carried out at the proposed facility in the Center are surveyed. (author)

Fast neutron dosimetry: Progress summary

International Nuclear Information System (INIS)

DeLuca, P.M. Jr.

1988-01-01

The purpose was to investigate the radiological physics and biology of very low energy photons derived from a 1-GeV electron synchrotron storage ring. An extensive beam line and irradiation apparatus was designed, developed, and constructed. Dosimetry measurements required invention and testing of a miniature absolute calorimeter and a cell irradiation fixture suitable for scanning exposures under computer control. Measurements of the kerma factors of oxygen, aluminum and silicon for 14-20 MeV neutrons. Custom designed miniature proportional counters of cylindrical symmetry were employed in these determinations. The oxygen kerma factor was found significantly lower than values calculated from microscopic cross sections. We also tested Mg and Fe walled conventional spherical counters. The direct neutron-counting gas interaction is significant enough for these counters that a correction is needed. We also investigated the application of Nuclear Magnetic Resonance spectroscopy to radiation dosimetry. Our purpose was to take advantage of recent development of very high-field magnets, complex RF-pulse techniques for solvent suppression, and improved spectral analysis techniques

Refractive neutron lens

International Nuclear Information System (INIS)

Petrov, P.V.; Kolchevsky, N.N.

2013-01-01

Model of the refractive neutron lens is proposed. System of N lenses acts as one thin lens with a complex refraction index n*. The maximum number N max of individual lenses for 'thick' neutron lens is calculated. Refractive neutron lens properties (resolution, focal depth) as function of resolution factor F 0 =ρbc/μ and depth of field factor dF 0 =λF 0 =λρbc/μ are calculated. It is shown that micro resolution of the refractive neutron optics is far from the wavelength in size and its open possibilities for progress in refractive neutron optics. (authors)

Latest developments of neutron scattering instrumentation at the Juelich Centre for Neutron Science

International Nuclear Information System (INIS)

Ioffe, Alexander

2013-01-01

Jülich Centre for Neutron Science (JCNS) is operating a number of world-class neutron scattering instruments situated at the most powerful and advanced neutron sources (FRM II, ILL and SNS) and is continuously undertaking significant efforts in the development and upgrades to keep this instrumentation in line with the continuously changing scientific request. These developments are mostly based upon the latest progress in neutron optics and polarized neutron techniques. For example, the low-Q limit of the suite of small angle-scattering instruments has been extended to 4·10 -5 Å -1 by the successful use of focusing optics. A new generation of correction elements for the neutron spin-echo spectrometer has allowed for the use of the full field integral available, thus pushing further the instrument resolution. A significant progress has been achieved in the developments of 3 He neutron spin filters for purposes of the wide-angle polarization analysis for off-specular reflectometry and (grazing incidence) small-angle neutron scattering, e.g. the on-beam polarization of 3 He in large cells is allowing to achieve a high neutron beam polarization without any degradation in time. The wide Q-range polarization analysis using 3 He neutron spin filters has been implemented for small-angle neutron scattering that lead to the reduction up to 100 times of the intrinsic incoherent background from non-deuterated biological molecules. Also the work on wide-angle XYZ magnetic cavities (Magic PASTIS) will be presented. (author)

[Fast neutron cross section measurements]: Progress report

International Nuclear Information System (INIS)

1988-01-01

As projected in our previous proposal, the past year on the cross section project at the University of Michigan has been one primarily of construction and assembly of our 14 MeV pulsed Neutron Facility. All the components of the system have now been either purchased or fabricated in our shop facilities and have been assembled in their final configuration. We are now in the process of testing the rf components that have been designed to deliver voltage to both the pulser and buncher stages. We expect that the system will be operational by the end of the current contract year. We have also accomplished the design and construction of several other major pieces of equipment that are needed to begin fast neutron time-of-flight measurements. These include the primary proton recoil detector, and a californium fission chamber needed in the efficiency calibration of the primary detector. We have also added considerable concrete shielding designed to lower the neutron background in the experimental area. 10 figs., 5 tabs

UCN gravity spectrometry using neutron interference filters for fundamental investigations in neutron optics

CERN Document Server

Bondarenko, I V; Cimmino, A; Geltenbort, P; Frank, A I; Hoghoj, P; Klein, A G; Masalovich, S V; Nosov, V G

2000-01-01

A Gravity Spectrometer for ultra-cold neutrons (UCN) using neutron interference filters has been designed and tested. An energy resolution of the order of 6.5 neV was obtained which is good enough for performing a number of neutron-optical experiments proposed in an earlier paper. Experimental tests of the UCN dispersion law are currently in progress.

UCN gravity spectrometry using neutron interference filters for fundamental investigations in neutron optics

International Nuclear Information System (INIS)

Bondarenko, I.V.; Balashov, S.N.; Cimmino, A.; Geltenbort, P.; Frank, A.I.; Hoghoj, P.; Klein, A.G.; Masalovich, S.V.; Nosov, V.G.

2000-01-01

A Gravity Spectrometer for ultra-cold neutrons (UCN) using neutron interference filters has been designed and tested. An energy resolution of the order of 6.5 neV was obtained which is good enough for performing a number of neutron-optical experiments proposed in an earlier paper. Experimental tests of the UCN dispersion law are currently in progress

Progress report from the Studsvik Neutron Research Laboratory 1987-89

International Nuclear Information System (INIS)

Dahlborg, U.; Ebbsjoe, I.; Holmqvist, B.

1993-01-01

The present publication contains information from activities at the Studsvik Neutron Research Laboratory (NFL) and the Department of Neutron Research. NFL is the base for the research activities at the Studvik reactors. It is administrated by the University of Uppsala and is established to facilitate reactor based research. The laboratory is intended to, in co-operation with institutes and departments at universities in Sweden, develop, construct and maintain experimental equipment for this kind of research and to make it available for scientists at Swedish universitites and, if possible, also to scientists outside the universities. The research at the Studsvik facilities has during 1989 been performed by groups from Uppsala University, Royal Institute of Technology in Stockholm, Chalmers Technical University, Gothenburg, and by scientists at NFL. The research program of the groups is divided into three main areas, scattering of thermal neutrons, nuclear chemistry and nuclear physics, and neutron capture radiography. The program for subatomic physics, especially neutron physics, at the Department for Neutron Research, Uppsala University has also staff permanently placed at NFL but they are in their research using the facilities at the The Svedberg Laboratory, Uppsala. In addition to supporting research NFL has also put substantial efforts on creating facilities for training of undergraduate students. Thus a facility for practical exercises in neutron physics, activation analysis and radiography has recently been installed at the R2-0 reactor as a collaboration between NFL, Dept. of Neutron Research, Upppsala and Department for Reactor Physics, KTH

Fast neutron dosimetry: [Progress report, 1986-1987

International Nuclear Information System (INIS)

DeLuca, P.M. Jr.; Gould, M.N.; Meisner, L.F.; Pearson, D.W.

1987-01-01

A new research area was initiated in ultrasoft x-rays with the University of Wisconsin 1-GeV electron storage ring used as a radiation source. A new beam line and irradiation apparatus was designed and constructed. Amongst the distinguishing features are an irradiation vessel of considerable generality allowing many types of radiological/biological experiments to be performed; the ability to maintain low-pressure, high humidity environments with good control; and a computer controlled sample slide for [X,Y,Z] motions of high precision that allows fully controlled velocities and accelerations for complex sample irradiations. Work in the area of chromosomal aberration studies has continued after the completion of the investigation into the possible synergistic effects of mixed beams of neutrons and photons. Of special interest is the damage dependence on absorbed dose and dose rate for low-dose and low-dose rate exposures to high LET radiation. A unique microdosimetric instrument was employed in the continuing effort to measure dose distribution in LET from fast neutron irradiation of metal-metal oxide walls. Our purpose is to determine this distribution for oxygen, an element of critical importance to fast neutron dosimetry. 31 refs., 7 figs., 2 tabs

Progress report on research and development in 1991, Institute of Neutron Physics and Reactor Engineering, KfK

International Nuclear Information System (INIS)

1992-03-01

Progress report on research and development in 1991 Institute of Neutron Physics and Reactor Engineering. The Institute of Neutron Physics and Reactor Engineering is concerned with research work in the field of nuclear engineering related to the safety of fast and thermal reactors as well as with specific problems of fusion reactor technology. Under the project of nuclear safety research, the Institute works on concepts designed to drastically improve reactor safety. Apart from that, methods to estimate and minimize the radiological consequences of reactor accidents are developed. Under the fusion technology project, the Institute deals with neutron physics and technological questions of the breeding blanket. Basic research covers technico-physical questions of the interaction between light ion radiation of a high energy density and matter. In addition and to a small extent, questions of employing hydrogen in the transport area are studied. For all these tasks it is indispensable to use up-to-date data processing methods and equipment, from the highest capacity computer to the integrated minicomputer system. (orig./DG) [de

Current Status and Progress of Developing a D-D Neutron Generator

International Nuclear Information System (INIS)

Kim, In-Jung; Jung, Hwa-Dong; Park, Chang-Su; Jung, Nam-Suk; Chung, Kyoung-Jae; Hwang, Yong-Seok; Choi, H. D.

2006-01-01

The research to develop a D-D neutron generator was begun in 2001. A prototype device was built in 2004, and partly modified in 2005. By using the modified prototype D-D neutron generator, neutron generation runs were performed, and the characteristics of D-D neutron generation was investigated. The final goal of maximum neutron yield is 10 8 n/s, while a yield of 6.5x10 7 n/s has been achieved. Here, the results of neutron generation runs performed by using the modified prototype device are summarized, and the feature of a new ion source to be tested in weeks is briefly described

Neutronic moderator design for the Spallation Neutron Source (SNS)

International Nuclear Information System (INIS)

Charlton, L.A.; Barnes, J.M.; Johnson, J.O.; Gabriel, T.A.

1998-01-01

Neutronics analyses are now in progress to support the initial selection of moderator design parameters for the Spallation Neutron Source (SNS). The results of the initial optimization studies involving moderator poison plate location, moderator position, and premoderator performance for the target system are presented in this paper. Also presented is an initial study of the use of a composite moderator to produce a liquid methane like spectrum

Progress in small angle neutron scattering activities in Malaysia

International Nuclear Information System (INIS)

Mohamed, Abudl Aziz Bin

2000-01-01

Research activities by use of small angle neutron scattering in Malaysia are briefly reported. Scattered neutron data are displayed in two or three-dimensional isometric view by the data acquisition system. Visual Basic is utilized for data acquisition and MathCad for data processing and analyses. (Y. Kazumata)

Progress in small angle neutron scattering activities in Malaysia

Energy Technology Data Exchange (ETDEWEB)

Mohamed, Abudl Aziz Bin [Industrial Technology Division, Malaysian Institute for Nuclear Technology Research (MINT) (Indonesia)

2000-10-01

Research activities by use of small angle neutron scattering in Malaysia are briefly reported. Scattered neutron data are displayed in two or three-dimensional isometric view by the data acquisition system. Visual Basic is utilized for data acquisition and MathCad for data processing and analyses. (Y. Kazumata)

Absolute measurements of neutron cross sections. Progress report

International Nuclear Information System (INIS)

1984-11-01

In the photoneutron laboratory, we have completed a major refurbishing of experimental facilities and begun work on measurements of the capture cross section in thorium and U-238. In the 14 MeV neutron experimental bay, work continues on the measurement of 14 MeV neutron induced reactions of interest as standards or because of their technological importance. First results have been obtained over the past year, and we are extending these measurements along the lines outlined in our proposal of a year ago

Progress in Neutron Diagnostics at JET

Czech Academy of Sciences Publication Activity Database

Mlynář, Jan; Bonheure, G.; Murari, A.; Bertalot, L.; Angelone, M.; Pillon, M.; Conroy, S.; Ericsson, G.; Kaellne, J.; Popovichev, S.

2006-01-01

Roč. 56, suppl.B (2006), B118-B124 ISSN 0011-4626. [Symposium on Plasma Physics and Technology /22nd./. Praha, 26.6.2006-29.6.2006] Institutional research plan: CEZ:AV0Z20430508 Keywords : tokamak * JET * fusion * neutrons diagnostics Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.568, year: 2006

Electronic neutron sensor based on coincidence detection

International Nuclear Information System (INIS)

Barelaud, B.; Decossas, J.L.; Mokhtari, F.; Vareille, J.C.

1996-01-01

The last symposium on neutron dosimetry which took place in Paris in November 1995 have shown again that it doesn't exist any individual active neutron dosemeter. The state of art on electronic device, the needs of the nuclear power industry in individual neutron monitoring and the new trends of The last symposium on neutron dosimetry which took place in Paris in November 1995 have shown again that it doesn't exist any individual active neutron dosemeter. The state of art on electronic device, the needs of the nuclear power industry in individual neutron monitoring and the new trends of researches were presented. They confirm the relevance of our studies in progress in the C2M team of the University of Limoges. The aim of this work is to realize an individual electronic neutron dosemeter. The device in the progress of being development will operate either as a dosemeter or as ratemeter giving H p (10) and H p (10) either as a spectrometer permitting to characterize the primary neutron beam. (author)

Spallation Neutron Source High Power RF Installation and Commissioning Progress

CERN Document Server

McCarthy, Michael P; Bradley, Joseph T; Fuja, Ray E; Gurd, Pamela; Hardek, Thomas; Kang, Yoon W; Rees, Daniel; Roybal, William; Young, Karen A

2005-01-01

The Spallation Neutron Source (SNS) linac will provide a 1 GeV proton beam for injection into the accumulator ring. In the normal conducting (NC) section of this linac, the Radio Frequency Quadupole (RFQ) and six drift tube linac (DTL) tanks are powered by seven 2.5 MW, 402.5 MHz klystrons and the four coupled cavity linac (CCL) cavities are powered by four 5.0 MW, 805 MHz klystrons. Eighty-one 550 kW, 805 MHz klystrons each drive a single cavity in the superconducting (SC) section of the linac. The high power radio frequency (HPRF) equipment was specified and procured by LANL and tested before delivery to ensure a smooth transition from installation to commissioning. Installation of RF equipment to support klystron operation in the 350-meter long klystron gallery started in June 2002. The final klystron was set in place in September 2004. Presently, all RF stations have been installed and high power testing has been completed. This paper reviews the progression of the installation and testing of the HPRF Sys...

Measurement and fitting of pulse shapes of moderators at IPNS [Intense Pulsed Neutron Source]: Progress report

International Nuclear Information System (INIS)

Bywater, R.L. Jr.; Williams, R.E.; Carpenter, J.M.

1988-01-01

We present a progress report on measurements and fitting of pulse shapes for neutrons emerging from one solid and two liquid methane moderators in IPNS. A time-focused crystal spectrometer arrangement was used with a cooled Ge monochromator. Data analysis of one of the liquid methane moderators has shown the need for some generalization of the Ikeda-Carpenter function that worked well for fitting pulse shapes of polyethylene moderators. We describe attempts to model physical insight into the wavelength dependence of function parameters. 5 refs., 7 figs

Progress made by Framatome in neutron flux mapping technology

International Nuclear Information System (INIS)

Mourlevat, J.L.

1999-01-01

A fixed in-core system based on self-powered neutron detectors (SPNDs) could improve the power distribution measurement accuracy and hence improve core operating margin knowledge. For that purpose, Framatome has tested rhodium neutron detectors as fixed in-core sensors. Two such in-core strings were installed during tie summer of 1997 at Golfech Unit 2, for a three-year experiment. (author)

Black and grey neutron detectors

International Nuclear Information System (INIS)

Gabbard, F.

1977-01-01

Recent progress in the development and use of ''black'' and ''grey'' detectors is reviewed. Such detectors are widely used for counting neutrons in (p,n) and (α,n) experiments and in neutron cross section measurements. Accuracy of each detector is stressed. 19 figures

Progress report 1978

International Nuclear Information System (INIS)

1979-01-01

The Studsvik Science Research Laboratory herewith presents its progress report for 1978. The report summarizes the current projects carried out by the research groups working at the laboratory. Projects within the following fields are presented: neutron physics, neutron absorption and scattering, radiation chemistry, radiation damage studies, radioactivity and theoretical studies of condensed matter. (E.R.)

Advanced Neutron Source (ANS) Project Progress report, FY 1991

International Nuclear Information System (INIS)

Campbell, J.H.; Selby, D.L.; Harrington, R.M.; Thompson, P.B.

1992-01-01

This report discusses the following about the Advanced Neutron Source: Project Management; Research and Development; Fuel Development; Corrosion Loop Tests and Analyses; Thermal-Hydraulic Loop Tests; Reactor Control and Shutdown Concepts; Critical and Subcritical Experiments; Material Data, Structural Tests, and Analysis; Cold-Source Development; Beam Tube, Guide, and Instrument Development; Hot-Source Development; Neutron Transport and Shielding; I ampersand C Research and Development; Design; and Safety

US progress on the development of CR-39 based neutron dosimeters

International Nuclear Information System (INIS)

Hadlock, D.E.

1987-06-01

Historically at US nuclear facilities, two types of personnel neutron dosimeters have been in routine use: nuclear track emulsion-Type A (NTA) film and thermoluminescent dosimeter (TLD)-albedo. Both of these dosimeters have energy-dependent responses. Therefore, the neutron energy spectra must be known, to interpret the dosimeter results properly. A new state-of-the-art dosimetry system has been developed within the US Department of Energy (US DOE) Personnel Neutron Dosimeter Evaluation and Upgrade Program. This system is called the combination thermoluminescent dosimeter/track etch dosimeter (TLD/TED). This paper briefly describes US DOE research currently being conducted to further enhance the TED portion of the combination TLD/TED system. The research areas involved include dose sensitivity, neutron energy range, specialized radiators, self-developing dosimeters, and neutron spectrometry. 1 fig., 1 tab

The Manuel Lujan Jr. Neutron Scattering Center (LANSCE) experiment reports 1993 run cycle. Progress report

Energy Technology Data Exchange (ETDEWEB)

Farrer, R.; Longshore, A. [comps.

1995-06-01

This year the Manuel Lujan Jr. Neutron Scattering Center (LANSCE) ran an informal user program because the US Department of Energy planned to close LANSCE in FY1994. As a result, an advisory committee recommended that LANSCE scientists and their collaborators complete work in progress. At LANSCE, neutrons are produced by spallation when a pulsed, 800-MeV proton beam impinges on a tungsten target. The proton pulses are provided by the Clinton P. Anderson Meson Physics Facility (LAMPF) accelerator and a associated Proton Storage Ring (PSR), which can Iter the intensity, time structure, and repetition rate of the pulses. The LAMPF protons of Line D are shared between the LANSCE target and the Weapons Neutron Research (WNR) facility, which results in LANSCE spectrometers being available to external users for unclassified research about 80% of each annual LAMPF run cycle. Measurements of interest to the Los Alamos National Laboratory (LANL) may also be performed and may occupy up to an additional 20% of the available beam time. These experiments are reviewed by an internal program advisory committee. This year, a total of 127 proposals were submitted. The proposed experiments involved 229 scientists, 57 of whom visited LANSCE to participate in measurements. In addition, 3 (nuclear physics) participating research teams, comprising 44 scientists, carried out experiments at LANSCE. Instrument beam time was again oversubscribed, with 552 total days requested an 473 available for allocation.

The Manuel Lujan Jr. Neutron Scattering Center (LANSCE) experiment reports 1993 run cycle. Progress report

International Nuclear Information System (INIS)

Farrer, R.; Longshore, A.

1995-06-01

This year the Manuel Lujan Jr. Neutron Scattering Center (LANSCE) ran an informal user program because the US Department of Energy planned to close LANSCE in FY1994. As a result, an advisory committee recommended that LANSCE scientists and their collaborators complete work in progress. At LANSCE, neutrons are produced by spallation when a pulsed, 800-MeV proton beam impinges on a tungsten target. The proton pulses are provided by the Clinton P. Anderson Meson Physics Facility (LAMPF) accelerator and a associated Proton Storage Ring (PSR), which can Iter the intensity, time structure, and repetition rate of the pulses. The LAMPF protons of Line D are shared between the LANSCE target and the Weapons Neutron Research (WNR) facility, which results in LANSCE spectrometers being available to external users for unclassified research about 80% of each annual LAMPF run cycle. Measurements of interest to the Los Alamos National Laboratory (LANL) may also be performed and may occupy up to an additional 20% of the available beam time. These experiments are reviewed by an internal program advisory committee. This year, a total of 127 proposals were submitted. The proposed experiments involved 229 scientists, 57 of whom visited LANSCE to participate in measurements. In addition, 3 (nuclear physics) participating research teams, comprising 44 scientists, carried out experiments at LANSCE. Instrument beam time was again oversubscribed, with 552 total days requested an 473 available for allocation

Euratom Neutron Radiography Working Group

DEFF Research Database (Denmark)

Domanus, Joseph Czeslaw

1986-01-01

reactor fuel as well as establish standards for radiographic image quality of neutron radiographs. The NRWG meets once a year in each of the neutron radiography centers to review the progress made and draw plans for the future. Besides, ad-hoc sub-groups or. different topics within the field of neutron......In 1979 a Neutron Radiography Working Group (NRWG) was constituted within Buratom with the participation of all centers within the European Community at which neutron facilities were available. The main purpose of NRWG was to standardize methods and procedures used in neutron radiography of nuclear...... radiography are constituted. This paper reviews the activities and achievements of the NRWG and its sub-groups....

Progress report on JAERI-ORNL cooperative neutron scattering research

International Nuclear Information System (INIS)

Iizumi, Masashi

1985-08-01

One year activities done under the JAERI-DOE(ORNL) cooperative neutron scattering program are summarized. This period just followed the completion of the wide-angle neutron diffractometer dedicated to the cooperative research. The report contains results of the performance test of the instrument and early research activities. The latter part includes the time-resolved measurements of the transition kinetics in tin and Ni-Mn alloy as well as the single-crystal diffraction by the flat-cone method. (author)

Cold neutron prompt gamma activation analysis at NIST; A progress report

Energy Technology Data Exchange (ETDEWEB)

Paul, R L; Lindstrom, R M [National Inst. of Standards and Technology, Gaithersburg, MD (United States). Div. of Inorganic Analytical Research; Vincent, D H [Michigan Univ., Ann Arbor, MI (United States). Dept. of Nuclear Engineering

1994-05-01

An instrument for prompt gamma-ray activation analysis is now in operation at the NIST Cold Neutron Research Facility (CNRF). The cold neutron beam is relatively free of contamination by fast neutrons and reactor gamma rays, and the neutron fluence rate is 1.5 x 10 [sup 8] cm [sup -2] x s [sup -1] (thermal equivalent). As a result of a compact target-detector geometry the sensitivity is better by a factor of as much as seven than that obtained with an existing thermal instrument, and hydrogen background is a factor of 50 lower. This instrument was applied to multielement analysis of the Allende meteorite and other materials. (author) 14 refs.; 2 figs.; 1 tab.

Intense neutron sources for cancer treatment

International Nuclear Information System (INIS)

Anon.

1977-01-01

Significant progress has been made in the development of small, solid-target, pulsed neutron sources for nuclear weapons applications. The feasibility of using this type of neutron source for cancer treatment is discussed. Plans for fabrication and testing of such a source is briefly described

Progress on using deuteron-deuteron fusion generated neutrons for 40Ar/39Ar sample irradiation

Science.gov (United States)

Rutte, Daniel; Renne, Paul R.; Becker, Tim; Waltz, Cory; Ayllon Unzueta, Mauricio; Zimmerman, Susan; Hidy, Alan; Finkel, Robert; Bauer, Joseph D.; Bernstein, Lee; van Bibber, Karl

2017-04-01

We present progress on the development and proof of concept of a deuteron-deuteron fusion based neutron generator for 40Ar/39Ar sample irradiation. Irradiation with deuteron-deuteron fusion neutrons is anticipated to reduce Ar recoil and Ar production from interfering reactions. This will allow dating of smaller grains and increase accuracy and precision of the method. The instrument currently achieves neutron fluxes of ˜9×107 cm-2s-1 as determined by irradiation of indium foils and use of the activation reaction 115In(n,n')115mIn. Multiple foils and simulations were used to determine flux gradients in the sample chamber. A first experiment quantifying the loss of 39Ar is underway and will likely be available at the time of the presentation of this abstract. In ancillary experiments via irradiation of K salts and subsequent mass spectrometric analysis we determined the cross-sections of the 39K(n,p)39Ar reaction at ˜2.8 MeV to be 160 ± 35 mb (1σ). This result is in good agreement with bracketing cross-section data of ˜96 mb at ˜2.45 MeV and ˜270 mb at ˜4 MeV [Johnson et al., 1967; Dixon and Aitken, 1961 and Bass et al. 1964]. Our data disfavor a much lower value of ˜45 mb at 2.59 MeV [Lindström & Neuer, 1958]. In another ancillary experiment the cross section for 39K(n,α)36Cl at ˜2.8 MeV was determined as 11.7 ± 0.5 mb (1σ), which is significant for 40Ar/39Ar geochronology due to subsequent decay to 36Ar as well as for the determination of production rates of cosmogenic 36Cl. Additional experiments resolving the cross section functions on 39K between 1.5 and 3.6 MeV are on their way using the LICORNE neutron source of the IPN Orsay tandem accelerator. Results will likely be available at the time of the presentation of this abstract. While the neutron generator is designed for fluxes of ˜109 cm-2s-1, arcing in the sample chamber currently limits the power—straightforwardly correlated to the neutron flux—the generator can safely be run at. Further

Fast neutron dosimetry

International Nuclear Information System (INIS)

DeLuca, P.M. Jr.; Pearson, D.W.

1991-01-01

During 1988--1990 the magnetic resonance dosimetry project was completed, as were the 250 MeV proton shielding measurements. The first cellular experiment using human cells in vitro at the 1 GeV electron storage ring was also accomplished. More detail may be found in DOE Report number-sign DOE/EV/60417-002 and the open literature cited in the individual progress subsections. We report Kinetic Energy Released in Matter (KERMA), factor measurements in several elements of critical importance to neutron radiation therapy and radiation protection for space habitation and exploration for neutron energies below 30 MeV. The results of this effort provide the only direct measurements of the oxygen and magnesium kerma factors above 20 MeV neutron energy, and the only measurements of the iron kerma factor above 15 MeV. They provide data of immediate relevance to neutron radiotherapy and impose strict criteria for normalizing and testing nuclear models used to calculate kerma factors at higher neutron energies

Energetic-neutron spectrometry. Progress report, 1 June 1975--31 May 1976

International Nuclear Information System (INIS)

Madey, R.

1976-01-01

Research accomplishments are outlined including measurement of the response of four scintillators to protons from about 2 to 20 MeV; measurement of the neutron spectrum from 20 to nearly 600 MeV above the roof shielding of the Brookhaven AGS; development of a 2-parameter spectrometer for unidirectional neutrons from 5 to 200 MeV; a temperature-stable linear gate for nanosecond signals from photomultipliers and an optional stretcher circuit; and planning for measurement of the neutron spectrum at 135 0 from the main beam stop at LAMPF

neutron radiography

International Nuclear Information System (INIS)

Barton, J.P.

1993-01-01

Neutron radiography (or radiology) is a diverse filed that uses neutrons of various energies, subthermal, thermal, epithermal or fast in either steady state or pulsed mode to examine objects for industrial, medical, or other purposes, both microscopic and macroscopic. The applications include engineering design, biological studies, nondestructive inspection and materials evaluation. In the past decade, over 100 different centers in some 30 countries have published reports of pioneering activities using reactors, accelerators and isotopic neutron sources. While film transparency and electronic video are most common imaging methods for static or in motion objects respectively, there are other important data gathering techniques, including track etch, digital gauging and computed tomography. A survey of the world-wide progress shows the field to be gaining steadily in its diversity, its sophistication and its importance. (author)

The progress of neutron induced prompt gamma analysis technique in 1988-2002

International Nuclear Information System (INIS)

Liu Yuren; Jing Shiwei

2003-01-01

The new development of the neutron induced prompt gamma-ray analysis (NIPGA) technology in 1988-2002 are described. The pulse fast-thermal neutron activation analysis method, which utilizes the inelastic reaction and capture reaction jointly is employed to measure the elemental content in the material more efficiently. The lifetime of the neutron generator is more than 10000 h and the capability of HPGe, TeZeCd and MCA (multi-channel analyser) reaches the high level. At the same time, Monte Carlo Library least-square method is used to solve the nonlinearity problem in the PGNAA (Prompt Gamma Neutron Activation Analysis)

Progress report from the Studsvik Neutron Research Laboratory 1990-91

International Nuclear Information System (INIS)

Dahlborg, U.; Ebbsjoe, I.; Holmqvist, B.

1992-01-01

The Studsvik Neutron Research Laboratory (NFL) is the base for the research activities at the Studsvik reactors. It is administrated by the University of Uppsala and is established to facilitate reactor based research. The laboratory is intended to, in co-operation with institutes and department at universities in Sweden, develop, construct and maintain experimental equipment for this kind of research and to make it available for scientists at Swedish universities and, if possible, also to scientists outside the universities. The research at the Studsvik facilities has during 1990 and 1991 been performed by groups form Uppsala University, Royal Institute of Technology, Stockholm, Chalmers Technical University, Gothenburg, and by scientists at NFL. The research programme of the groups is divided into three main areas, scattering of thermal neutrons, nuclear chemistry/nuclear physics, and neutron capture radiography

Status of ITER neutron diagnostic development

International Nuclear Information System (INIS)

Sasao, M.; Krasilnikov, A.V.; Kaschuck, Yu.A.; Nishitani, T.; Batistoni, P.; Zaveryaev, V.S.; Popovichev, S.; Jarvis, O.N.; Iguchi, T.; Kaellne, J.; Fiore, C.L.; Roquemore, A.L.; Heidbrink, W.W.; Fisher, R.; Gorini, G.; Donne, A.J.H.; Costley, A.E.; Walker, C.I.

2005-01-01

Due to the high neutron yield and the large plasma size many ITER plasma parameters such as fusion power, power density, ion temperature, fast ion energy and their spatial distributions in the plasma core can be well measured by various neutron diagnostics. Neutron diagnostic systems under consideration and development for ITER include: radial and vertical neutron cameras (RNC and VNC), internal and external neutron flux monitors, neutron activation systems and neutron spectrometers. The two-dimensional neutron source strength and spectral measurements can be provided by the combined RNC and VNC. The neutron flux monitors need to meet the ITER requirement of time-resolved measurements of the neutron source strength and can provide the signals necessary for real-time control of the ITER fusion power. Compact and high throughput neutron spectrometers are under development. A concept for the absolute calibration of neutron diagnostic systems is proposed. The development, testing in existing experiments and the engineering integration of all neutron diagnostic systems into ITER are in progress and the main results are presented. (author)

Research trends in neutron physics

International Nuclear Information System (INIS)

Lynn, J.E.

1976-01-01

The trends in neutron research are discussed from the viewpoints of development of pulsed neutron sources, the ingenuity of specialization of instrumentation and experimental techniques, and research programs. The latter comprise the large and still expanding requirements of nuclear data for nuclear power technology, the requirements of other fundamental sciences, and the experimental and theoretical developments required for a more fundamental understanding of the subject of neutron and related nuclear reactions itself. The general conclusion is that high energy resolution coupled with high intensity for detecting weak reactions provides the key to further progress, and that (provided financial limitations do not stifle the further development of experimental facilities, particularly neutron sources) the subject of neutron physics still has a long and fruitful future

Instrumentation with polarized neutrons

International Nuclear Information System (INIS)

Boeni, P.; Muenzer, W.; Ostermann, A.

2009-01-01

Neutron scattering with polarization analysis is an indispensable tool for the investigation of novel materials exhibiting electronic, magnetic, and orbital degrees of freedom. In addition, polarized neutrons are necessary for neutron spin precession techniques that path the way to obtain extremely high resolution in space and time. Last but not least, polarized neutrons are being used for fundamental studies as well as very recently for neutron imaging. Many years ago, neutron beam lines were simply adapted for polarized beam applications by adding polarizing elements leading usually to unacceptable losses in neutron intensity. Recently, an increasing number of beam lines are designed such that an optimum use of polarized neutrons is facilitated. In addition, marked progress has been obtained in the technology of 3 He polarizers and the reflectivity of large-m supermirrors. Therefore, if properly designed, only factors of approximately 2-3 in neutron intensity are lost. It is shown that S-benders provide neutron beams with an almost wavelength independent polarization. Using twin cavities, polarized beams with a homogeneous phase space and P>0.99 can be produced without significantly sacrificing intensity. It is argued that elliptic guides, which are coated with large m polarizing supermirrors, provide the highest flux.

Beyond KERMA - neutron data for biomedical applications

International Nuclear Information System (INIS)

Blomgren, J.; Olsson, N.

2003-01-01

Presently, many new applications of fast neutrons are emerging or under development, like dose effects due to cosmic-ray neutrons for airplane crew, fast-neutron cancer therapy, studies of electronic failures induced by cosmic-ray neutrons, and accelerator-driven incineration of nuclear waste and energy production technologies. All these areas would benefit from improved neutron dosimetry. In this paper, the present rapid progress on measurements of double-differential neutron-induced nuclear reaction data are described. With such data at hand, the full response of, in principle, any system, including human tissue, can be calculated in detail. This could potentially revolutionise our understanding of biological effects in tissue due to fast neutrons. (author)

Physics of Neutron Star Crusts

Directory of Open Access Journals (Sweden)

Chamel Nicolas

2008-12-01

Full Text Available 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.

1995-1996 progress report

International Nuclear Information System (INIS)

1997-09-01

This progress report is mainly devoted to the scientific activity of the LLB or carried out in collaboration with external laboratories. The activity of the LLB is split in several chapters dealing with: magnetism, superconductivity, structures (including lattice dynamics), phase transitions, C 60 , quasi-crystal systems, disordered systems (amorphous, liquids, crystal solid solutions), biology, soft matter (polymers and colloids), physical metallurgy and materials science. Neutron scattering is the main tool used in all these topics but other techniques are also used such as: polarized neutron reflectivity, cold neutrons diffraction, NMR, synchrotron radiation etc. (J.S.)

Prospects for neutron-antineutron transition search

International Nuclear Information System (INIS)

Kamyshkov, Y.; Tennessee Univ., Knoxville, TN

1996-01-01

Presently-available sources of free neutrons can allow an improvement in the discovery potential of a neutron-antineutron transition search by four orders of magnitude as compared to that of the most recent reactor-based search experiment performed at ILL in Grenoble. This would be equivalent to a characteristic neutron-antineutron transition time limit of >10 10 seconds. With future dedicated neutron-source Facilities, with further progress in cold-neutron- moderator techniques, and with a vertical experiment layout, the discovery potential could ultimately be pushed by another factor of ∼100 corresponding to a characteristic transition time limit of ∼10 11 seconds. Prospects for, and relative merits of, a neutron-antineutron oscillation search in intranuclear transitions are also discussed

Status of ITER neutron diagnostic development

Science.gov (United States)

Krasilnikov, A. V.; Sasao, M.; Kaschuck, Yu. A.; Nishitani, T.; Batistoni, P.; Zaveryaev, V. S.; Popovichev, S.; Iguchi, T.; Jarvis, O. N.; Källne, J.; Fiore, C. L.; Roquemore, A. L.; Heidbrink, W. W.; Fisher, R.; Gorini, G.; Prosvirin, D. V.; Tsutskikh, A. Yu.; Donné, A. J. H.; Costley, A. E.; Walker, C. I.

2005-12-01

Due to the high neutron yield and the large plasma size many ITER plasma parameters such as fusion power, power density, ion temperature, fast ion energy and their spatial distributions in the plasma core can be measured well by various neutron diagnostics. Neutron diagnostic systems under consideration and development for ITER include radial and vertical neutron cameras (RNC and VNC), internal and external neutron flux monitors (NFMs), neutron activation systems and neutron spectrometers. The two-dimensional neutron source strength and spectral measurements can be provided by the combined RNC and VNC. The NFMs need to meet the ITER requirement of time-resolved measurements of the neutron source strength and can provide the signals necessary for real-time control of the ITER fusion power. Compact and high throughput neutron spectrometers are under development. A concept for the absolute calibration of neutron diagnostic systems is proposed. The development, testing in existing experiments and the engineering integration of all neutron diagnostic systems into ITER are in progress and the main results are presented.

Status of ITER neutron diagnostic development

International Nuclear Information System (INIS)

Krasilnikov, A.V.; Sasao, M.; Kaschuck, Yu.A.; Nishitani, T.; Batistoni, P.; Zaveryaev, V.S.; Popovichev, S.; Iguchi, T.; Jarvis, O.N.; Kaellne, J.; Fiore, C.L.; Roquemore, A.L.; Heidbrink, W.W.; Fisher, R.; Gorini, G.; Prosvirin, D.V.; Tsutskikh, A.Yu.; Donne, A.J.H.; Costley, A.E.; Walker, C.I.

2005-01-01

Due to the high neutron yield and the large plasma size many ITER plasma parameters such as fusion power, power density, ion temperature, fast ion energy and their spatial distributions in the plasma core can be measured well by various neutron diagnostics. Neutron diagnostic systems under consideration and development for ITER include radial and vertical neutron cameras (RNC and VNC), internal and external neutron flux monitors (NFMs), neutron activation systems and neutron spectrometers. The two-dimensional neutron source strength and spectral measurements can be provided by the combined RNC and VNC. The NFMs need to meet the ITER requirement of time-resolved measurements of the neutron source strength and can provide the signals necessary for real-time control of the ITER fusion power. Compact and high throughput neutron spectrometers are under development. A concept for the absolute calibration of neutron diagnostic systems is proposed. The development, testing in existing experiments and the engineering integration of all neutron diagnostic systems into ITER are in progress and the main results are presented

Low temperature and neutron physics studies. Progress report, September, 1977--April, 1979

International Nuclear Information System (INIS)

Shull, C.G.

1979-04-01

Experimental research work with the neutron diffraction spectrometers at the MIT Research Reactor concentrated during the past period in two general areas, a study of diamagnetic scattering of neutrons by bismuth and physical effects associated with dynamical diffraction by perfect crystals. The former study showed that the outermost valence (or lattice) electrons contribute dominantly to the field-induced diamagnetism. Fourier transformation of the scattering data provided maps showing the distribution of diamagnetization density throughout the unit cell with pronounced spatial variations. In the latter studies, some of the anomalous effects associated with neutron propagation through diffracting perfect crystals were investigated. These include the very sensitive modification of transport direction within the crystal when the entrance direction is changed slightly or when the neutron energy is changed slightly by applicaton of a modest magnetic field. Additional studies have shown that neutrons propagate through a diffracting crystal with a drift velocity which can be pronouncedly smaller than the usual group velocity

Low-temperature and neutron-physics studies. Progress report, July 1981-June 1982

International Nuclear Information System (INIS)

1982-07-01

Experimental and theoretical studies of the neutron diffraction group at the MIT Research Reactor have concentrated during the past year in the areas of neutron interferometry and fundamental diffraction by crystals. A comprehensive study of the neutron phase effects introduced upon rotational motion of an interferometer has been carried out and found to agree with high accuracy to that predicted by theory. This effect arises because of the Coriolis force acting on the neutron radiation and a full theoretical analysis of this effect as it occurs in the finite crystals of an interferometer suggests the use of an effective mass concept similar to that for electrons in a crystal. Studies were also performed on the interesting case where neutron radiation can simultaneously satisfy the requirements of both surface optical reflection and internal Bragg diffraction. Theoretical analysis predicts that the competing processes will modify the characteristics of either one and experiments have been carried out which demonstrate these features

Fast-neutron dosimetry. Progress report, 1 July 1982-30 June 1983

International Nuclear Information System (INIS)

DeLuca, P.M. Jr.; Attix, F.H.; Gould, M.N.

1983-01-01

Several aspects of neutron and related photon radiological physics are being actively investigated. These research topics relate to measurement techniques, basic data values and theoretical discussions. In addition, a modest radiobiological effort is pursued concurrently. The unique coupled neutron/photon source provides an excellent tool for this latter work

Neutron scattering science in Australia

International Nuclear Information System (INIS)

Knott, Robert

1999-01-01

Neutron scattering science in Australia is making an impact on a number of fields in the scientific and industrial research communities. The unique properties of the neutron are being used to investigate problems in chemistry, materials science, physics, engineering and biology. The reactor HIFAR at the Australian Nuclear Science and Technology Organisation research laboratories is the only neutron source in Australia suitable for neutron scattering science. A suite of instruments provides a wide range of opportunities for the neutron scattering community that extends throughout universities, government and industrial research laboratories. Plans are in progress to replace the present research reactor with a modern multi-purpose research reactor to offer the most advanced neutron scattering facilities. The experimental and analysis equipment associated with a modern research reactor will permit the establishment of a national centre for world class neutron science research focussed on the structure and functioning of materials, industrial irradiations and analyses in support of Australian manufacturing, minerals, petrochemical, pharmaceuticals and information science industries. (author)

Neutron scattering science in Australia

Energy Technology Data Exchange (ETDEWEB)

Knott, Robert [Australian Nuclear Science and Technology Organisation, Menai, NSW (Australia)

1999-10-01

Neutron scattering science in Australia is making an impact on a number of fields in the scientific and industrial research communities. The unique properties of the neutron are being used to investigate problems in chemistry, materials science, physics, engineering and biology. The reactor HIFAR at the Australian Nuclear Science and Technology Organisation research laboratories is the only neutron source in Australia suitable for neutron scattering science. A suite of instruments provides a wide range of opportunities for the neutron scattering community that extends throughout universities, government and industrial research laboratories. Plans are in progress to replace the present research reactor with a modern multi-purpose research reactor to offer the most advanced neutron scattering facilities. The experimental and analysis equipment associated with a modern research reactor will permit the establishment of a national centre for world class neutron science research focussed on the structure and functioning of materials, industrial irradiations and analyses in support of Australian manufacturing, minerals, petrochemical, pharmaceuticals and information science industries. (author)

The neutron discovery

International Nuclear Information System (INIS)

Six, J.

1987-01-01

The neutron: who had first the idea, who discovered it, who established its main properties. To these apparently simple questions, multiple answers exist. The progressive discovery of the neutron is a marvellous illustration of some characteristics of the scientific research, where the unforeseen may be combined with the expected. This discovery is replaced in the context of the 1930's scientific effervescence that succeeded the revolutionary introduction of quantum mechanics. This book describes the works of Bothe, the Joliot-Curie and Chadwick which led to the neutron in an unexpected way. A historical analysis allows to give a new interpretation on the hypothesis suggested by the Joliot-Curie. Some texts of these days will help the reader to revive this fascinating story [fr

Neutron capture therapy. Principles and applications

International Nuclear Information System (INIS)

Sauerwein, Wolfgang A.G.; Moss, Raymond; Wittig, Andrea; Nakagawa, Yoshinobu

2012-01-01

State of the art report on neutron capture therapy. Summarizes the progress made in recent decades. Multidisciplinary approach. Written by the most experienced specialists Neutron capture therapy (NCT) is based on the ability of the non-radioactive isotope boron-10 to capture thermal neutrons with very high probability and immediately to release heavy particles with a path length of one cell diameter. This in principle allows for tumor cell-selective high-LET particle radiotherapy. NCT is exciting scientifically but challenging clinically, and a key factor in success is close collaboration among very different disciplines. This book provides a comprehensive summary of the progress made in NCT in recent years. Individual sections cover all important aspects, including neutron sources, boron chemistry, drugs for NCT, dosimetry, and radiation biology. The use of NCT in a variety of malignancies and also some non-malignant diseases is extensively discussed. NCT is clearly shown to be a promising modality at the threshold of wider clinical application. All of the chapters are written by experienced specialists in language that will be readily understood by all participating disciplines.

Neutron effects on living things

International Nuclear Information System (INIS)

1964-01-01

Scientific interest in neutrons and protons - two fundamental particles of the atomic nucleus - has grown in recent years as the technology of peaceful uses of atomic energy has progressed. Such interest also has increased because both protons and neutrons are encountered in outer space. However, only recently has a thorough study of the biological effects of neutrons and protons become possible, as a result of progress in making physical measurements of the radiation dose absorbed in biological systems (of plants and animals, for example). Reports of work in that field were presented in December 1962, when IAEA sponsored at Harwell Laboratory in the United Kingdom the first international symposium on detection dosimetry (measurement) and standardization of neutron radiation sources. The Harwell meeting was followed in October 1963 at Brookhaven National Laboratory, Long Island, New York, by the first scientific meeting sponsored by IAEA in the U. S. Entitled 'Biological Effects of Neutron Irradiations', the Symposium continued the review of problems of measuring radiation absorption in living things and provided in addition for several reports dealing with the effects of radiation on living organisms - plant, animal and human - and with delayed consequences of exposure to radiation, such as: change in life span; tumour incidence; and fertility. Eighteen countries were represented. Although much has been learned about X-ray and gamma-ray effects, comparatively little is known about the biological effects of neutrons, and therefore many of the Symposium papers reviewed the various aspects of neutron experimentation. Similarly, since there is increasing interest in the biological effects of protons, papers were given on that related subject.

Fast neutron dosimetry

International Nuclear Information System (INIS)

DeLuca, P.M. Jr.; Pearson, D.W.

1992-01-01

This progress report concentrates on two major areas of dosimetry research: measurement of fast neutron kerma factors for several elements for monochromatic and white spectrum neutron fields and determination of the response of thermoluminescent phosphors to various ultra-soft X-ray energies and beta-rays. Dr. Zhixin Zhou from the Shanghai Institute of Radiation Medicine, People's Republic of China brought with him special expertise in the fabrication and use of ultra-thin TLD materials. Such materials are not available in the USA. The rather unique properties of these materials were investigated during this grant period

Forensic neutron activation analysis

International Nuclear Information System (INIS)

Kishi, T.

1987-01-01

The progress of forensic neutron activation analysis (FNAA) in Japan is described. FNAA began in 1965 and during the past 20 years many cases have been handled; these include determination of toxic materials, comparison examination of physical evidences (e.g., paints, metal fragments, plastics and inks) and drug sample differentiation. Neutron activation analysis is applied routinely to the scientific criminal investigation as one of multielement analytical techniques. This paper also discusses these routine works. (author) 14 refs

Study of structure of nuclei with neutrons and nuclear data measurements for MFE. Progress report, December 1, 1981-July 31, 1984

International Nuclear Information System (INIS)

Lane, R.O.; Grimes, S.M.

1984-01-01

Measurements of cross sections for neutron induced reactions of interest to the fusion energy program have been carried out. These measurements include neutron elastic and inelastic cross sections for 6 Li, 11 B, 13 C and 18 O as well as cross sections for 6 Li(n,t)α, 58 Ni(n,z), 60 Ni(n,z) and stainless steel (n,z) reactions. Most of these data have been analyzed using either R-marix studies or Hauser-Feshback calculations. Details of these measurements and analyses are given. Improvements to the facilities at this Laboratory are also described. A new shell model code has been developed to aid in studies of nuclear structure and reaction mechanisms. A description of the code and a summary of the structure and level density calculations now in progress are given

Communication of nuclear data progress: No.7 (1992)

International Nuclear Information System (INIS)

1992-06-01

This is the seventh issue of communication of Nuclear Data Progress (CNDP), in which the nuclear data progress in china during the last year is presented. It includes 14 MeV neutron activation cross section nuclear decay data inelastic angular distribution integral prompt spontaneous fission neutron spectrum and α spectrum measurements of reaction 40 Ca(n, α); programs UNF-for fast neutron data calculation of structural materials, APCOM and APOM for searching optimal charged particle and neutron optical potential parameters respectively; P + 63 Cu reaction calculation in energy region 3 ∼ 55 MeV; evaluation of 197 Au (n, Zn) 196 Au cross section, progress on nuclear structure and decay data evaluation for A-chain a database on ion-atom collision processes, and evaluation of trapping and desorption data, systematics calculation of nuclear data for radiation damage assessment and related safety aspects, and systematics of (n, t) and (n, 3 He) reaction cross sections at 14 MeV, construction of covariance matrix for experimental data, Spline fit for multi-sets of correlative data etc

Synthesis and study of neutron-rich nuclides

International Nuclear Information System (INIS)

Luo Yixiao

1995-01-01

During the past few years our understanding of the decay properties and nuclear structure has been extended in a systematic fashion for the neutron-rich nuclei. This review will first sketch the production and identification of the neutron-rich nuclei throughout the whole mass region, and will then discuss the impressive progress in the studies of the exotic decay properties and nuclear structure of neutron-rich nuclei. Their astrophysical implications will also be outlined

Progress in multidimensional neutron transport computation

International Nuclear Information System (INIS)

Lewis, E.E.

1977-01-01

The methods available for solution of the time-independent neutron transport problems arising in the analysis of nuclear systems are examined. The merits of deterministic and Monte Carlo methods are briefly compared. The capabilities of deterministic computational methods derived from the first-order form of the transport equation, from the second-order even-parity form of this equation, and from integral transport formulations are discussed in some detail. Emphasis is placed on the approaches for dealing with the related problems of computer memory requirements, computational cost, and achievable accuracy. Attention is directed to some areas where problems exist currently and where the need for further work appears to be particularly warranted

Status and neutron scattering experiments at KENS

International Nuclear Information System (INIS)

Watanabe, N.; Sasaki, H.; Ishikawa, Y.; Endoh, Y.; Inoue, K.

1983-01-01

This paper reports present status of the KENS facility, progress in neutron scattering experiments and instrumental developments, and status of the KENS-I' program. A design study of a high intensity rapid-cycle 800 MeV proton synchrotron for proposed new pulsed neutron (KENS-II) and meson source is also descirbed

Neutronics calculation of RTP core

Science.gov (United States)

Rabir, Mohamad Hairie B.; Zin, Muhammad Rawi B. Mohamed; Karim, Julia Bt. Abdul; Bayar, Abi Muttaqin B. Jalal; Usang, Mark Dennis Anak; Mustafa, Muhammad Khairul Ariff B.; Hamzah, Na'im Syauqi B.; Said, Norfarizan Bt. Mohd; Jalil, Muhammad Husamuddin B.

2017-01-01

Reactor calculation and simulation are significantly important to ensure safety and better utilization of a research reactor. The Malaysian's PUSPATI TRIGA Reactor (RTP) achieved initial criticality on June 28, 1982. The reactor is designed to effectively implement the various fields of basic nuclear research, manpower training, and production of radioisotopes. Since early 90s, neutronics modelling were used as part of its routine in-core fuel management activities. The are several computer codes have been used in RTP since then, based on 1D neutron diffusion, 2D neutron diffusion and 3D Monte Carlo neutron transport method. This paper describes current progress and overview on neutronics modelling development in RTP. Several important parameters were analysed such as keff, reactivity, neutron flux, power distribution and fission product build-up for the latest core configuration. The developed core neutronics model was validated by means of comparison with experimental and measurement data. Along with the RTP core model, the calculation procedure also developed to establish better prediction capability of RTP's behaviour.

Neutron transmutation doping of gallium arsenide

International Nuclear Information System (INIS)

Alexiev, D.

1987-12-01

Neutron transmutation doping (NTD) was studied as a means of compensating p-type Cd-doped GaAs. By introducing specific donor concentrations, the net acceptor level was measured and showed a progressive reduction. The NTD constant K = 0.32 donor atoms.cm 3 per cm 2 was also measured. Radiation damage caused by neutron bombardment was annealed and no additional traps were generated

From free to bound water - progress in hydratisation for concrete, measured by means of neutron small angle scatter

International Nuclear Information System (INIS)

Hempel, M.; Haeussler, F.; Eichhorn, E.

1993-01-01

Neutron small angle scatter (NSAS) is suitable for characterising matrix non-homogeneousness in many materials. The description of amorphous materials (distribution of clusters, defect structures, boundary surfaces, e.g.: Between pores and the solid matrix etc.) is possible, in principle, by NSAS. This method is non-destructive to the extent that no pretreatment of samples is necessary, which significantly affects the microstructure to be examined. The process of NSAS itself produces no changes in the sample regarding the target of the examination. Thus the progress of hydratisation in concrete can be observed by successive NSAS measurements in time. (orig./HP) [de

Material science and neutron scattering

International Nuclear Information System (INIS)

1983-01-01

Neutron scattering experiments complete and extend the condensed matter studies made with X and gamma rays. Then story show a permanent evolution of the instrumentation, methods and experimental techniques to improve the result quality. This is more especially important as neutron sources are weaker than photon and electron sources. Progress in this research domain is due, in most part, to discovery and development of materials for the different measurement device components [fr

Status of neutron complex of INR RAS

Energy Technology Data Exchange (ETDEWEB)

Grachev, M I; Koptelov, E A; Kravchuk, L V; Matveev, V A; Perekrestenko, A D; Sidorkin, S F [Institute for Nuclear Research of Russian Academy of Sciences, Prospekt, Moscow (Russian Federation); Stavissky, Y Y

2001-03-01

The neutron complex of INR RAS consists of two sources of neutrons, beam stop, lead slowing down spectrometer and solid state spectrometers. The description of objects and their condition, the program of planned researches, co-operation with other institutes of the Moscow Region, progress reached for last two years are introduced in the article. (author)

Status of neutron complex of INR RAS

International Nuclear Information System (INIS)

Grachev, M.I.; Koptelov, E.A.; Kravchuk, L.V.; Matveev, V.A.; Perekrestenko, A.D.; Sidorkin, S.F.; Stavissky, Y.Y.

2001-01-01

The neutron complex of INR RAS consists of two sources of neutrons, beam stop, lead slowing down spectrometer and solid state spectrometers. The description of objects and their condition, the program of planned researches, co-operation with other institutes of the Moscow Region, progress reached for last two years are introduced in the article. (author)

Nuclear physics and neutronics

International Nuclear Information System (INIS)

Paya, D.

1997-01-01

After a brief review of the beginnings of the nuclear reaction physics in France in the 40's and 50's, the experimentation neutronics and nuclear physics studies are related and their uses presented, which aims were to provide data for the study of the various reactor concepts and to study fundamental physics. Progressively, pure nuclear physics lost its links with neutronics, and its influence decreases more or less. Long life radioactive waste reprocessing is an important domain where it could regain its contribution

Calibration issues for neutron diagnostics

International Nuclear Information System (INIS)

Sadler, G.J.; Adams, J.M.; Barnes, C.W.

1997-10-01

In order for ITER to meet its operational and programmatic goals, it will be necessary to measure a wide range of plasma parameters. Some of the required parameters e.g., neutron yield, fusion power and power density, ion temperature profile in the core plasma, and characteristics of confined and escaping alpha particle populations are best measured by fusion product diagnostic techniques. To make these measurements, ITER will have dedicated diagnostic systems, including radial and vertical neutron cameras, neutron and gamma ray spectrometers, internal and external fission chambers, a neutron activation system, and diagnostics for confined and escaping alpha particles. Engineering integration of many of these systems is in progress, and other systems are under investigation. This paper summarizes the present state of design of fusion product diagnostic systems for ITER and discusses expected measurement capability

IPNS progress report 2001-2006.

Energy Technology Data Exchange (ETDEWEB)

Marzec, B.

2006-11-27

In August 1981, the proton beam from the rapid cycling synchrotron (RCS) was first delivered to the Intense Pulsed Neutron Source (IPNS) neutron scattering target and now, in June 2006, it is with great joy that we celebrate the impending 25th anniversary of this event. This edition of the IPNS Progress Report will focus on the development and scientific accomplishments of the past 5 years, since our last Progress Report, but with some mention of the 25 years of IPNS experience. It is appropriate at this anniversary date to recall some of the more significant historic events that have led to the present IPNS and discuss some of the plans that will lead to even more successes. Below is a brief chronology that captures some of the developments of IPNS: 8/4/81 - First beam delivered to the neutron scattering target; 6/10/84 - IPNS produced its one billionth neutron pulse; 1/10/85 - Installed world's first solid methane moderator; 6/30/87 - 1000th experiment performed at IPNS; 9/19/87 - IPNS produced its two billionth neutron pulse; 11/20/91 - 2000th experiment performed at IPNS; 4/17/04 - IPNS produced its eight billionth neutron pulse; and 8/19/05 - 7000th experiment performed at IPNS. During the past 5 years, several significant source and instrument developments have taken place. Most of these are discussed in more detail elsewhere in the report, but three of the ones most visible to users are mentioned here.

Neutron scattering (Progress-Report) January - December 1992

International Nuclear Information System (INIS)

1993-02-01

The Laboratory for Neutron Scattering (LNS) is a joint venture between the Eidgenoessische Technische Hochschule Zurich (ETHZ) and the Paul Scherrer Institut Wuerenlingen/Villigen (PSI). The present report summarizes the laboratory's activities in 1992 as well as the work performed by external users at the reactor Saphir. It is intended as an interim description of ongoing research projects and as such may not contain the final conclusions of the analysis. However, the number and quality of the reports reflects very well the standard of experiments performed at the LNS. (author) figs., tabs., refs

Upgrade of detectors of neutron instruments at Neutron Physics Laboratory in Řež

Energy Technology Data Exchange (ETDEWEB)

Litvinenko, E.I., E-mail: litvin@nf.jinr.ru [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 14980 Dubna (Russian Federation); Ryukhtin, V. [Nuclear Physics Institute of the CAS v.v.i., Řež 130, 250 68 Řež (Czech Republic); Bogdzel, A.A.; Churakov, A.V. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 14980 Dubna (Russian Federation); Farkas, G. [Charles University in Prague, Department of Physics of Material, Ke Karlovu 5, CZ-12116 Prague (Czech Republic); Hervoches, Ch.; Lukas, P. [Nuclear Physics Institute of the CAS v.v.i., Řež 130, 250 68 Řež (Czech Republic); Pilch, J. [Nuclear Physics Institute of the CAS v.v.i., Řež 130, 250 68 Řež (Czech Republic); Institute of Physics, Czech Academy of Sciences, Na Slovance 1992/2, 1822 Prague (Czech Republic); Saroun, J.; Strunz, P. [Nuclear Physics Institute of the CAS v.v.i., Řež 130, 250 68 Řež (Czech Republic); Zhuravlev, V.V. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 14980 Dubna (Russian Federation)

2017-01-01

Three neutron instruments at the Neutron Physics Laboratory (NPL) in Řež near Prague — small-angle scattering (SANS) MAUD, strain scanner SPN-100 and strain diffractometer TKSN-400 — have been modernized recently with new 2D position-sensitive detectors (PSDs) from JINR, Dubna. Here we report on the progress made in relation to the possibilities of the diffractometers due to the improved performance of the detectors. The first part of the paper is dedicated to a detailed description of the hardware and software of the PSDs, as well as its integration with the in-house experimental control software. Then practical examples of neutron scattering experiments for each of the upgraded facilities are presented.

Neutron-scattering studies of chromatin

International Nuclear Information System (INIS)

Bradbury, E.M.; Baldwin, J.P.; Carpenter, B.G.; Hjelm, R.P.; Hancock, R.; Ibel, K.

1976-01-01

It is clear that a knowledge of the basic molecular structure of chromatin is a prerequisite for any progress toward an understanding of chromosome organization. With a two-component system, protein and nucleic acid, neutrons have a particularly powerful application to studies of the spatial arrangements of these components because of the ability, by contrast matching with H 2 O-D 2 O mixtures, to obtain neutron-scattering data on the individual components. With this approach it has been shown that the neutron diffraction of chromatin is consistent with a ''beads on a string'' model in which the bead consists of a protein core with DNA coiled on the outside. However, because chromatin is a gel and gives limited structural data, confirmation of such a model requires extension of the neutron studies by deuteration of specific chromatin components and the isolation of chromatin subunits. Although these studies are not complete, the neutron results so far obtained support the subunit model described above

Fast neutron dosimetry

International Nuclear Information System (INIS)

DeLuca, P.M. Jr.; Pearson, D.W.

1993-01-01

Research concentrated on three major areas during the last twelve months: (1) investigations of energy fluence and absorbed dose measurements using crystalline and hot pressed TLD materials exposes to ultrasoft beams of photons, (2) fast neutron kerma factor measurements for several important elements as well as NE-213 scintillation material response function determinations at the intense ''white'' source available at the WNR facility at LAMPF, and (3) kerma factor ratio determinations for carbon and oxygen to A-150 tissue equivalent plastic at the clinical fast neutron radiation facility at Harper Hospital, Detroit, MI. Progress summary reports of these efforts are given in this report

Theory of neutron star magnetospheres

CERN Document Server

Curtis Michel, F

1990-01-01

An incomparable reference for astrophysicists studying pulsars and other kinds of neutron stars, "Theory of Neutron Star Magnetospheres" sums up two decades of astrophysical research. It provides in one volume the most important findings to date on this topic, essential to astrophysicists faced with a huge and widely scattered literature. F. Curtis Michel, who was among the first theorists to propose a neutron star model for radio pulsars, analyzes competing models of pulsars, radio emission models, winds and jets from pulsars, pulsating X-ray sources, gamma-ray burst sources, and other neutron-star driven phenomena. Although the book places primary emphasis on theoretical essentials, it also provides a considerable introduction to the observational data and its organization. Michel emphasizes the problems and uncertainties that have arisen in the research as well as the considerable progress that has been made to date.

Communication of nuclear data progress (No.29)

International Nuclear Information System (INIS)

2003-01-01

This is the 29th issue of Communication of Nuclear Data Progress (CNDP), in which the progress and achievements in nuclear data field in 2002 in China are carried. It includes the evaluations of complete neutron data for n+ 55,58 Mn, 99,100 Mo and covariance data evaluation for 63,65,Nat Cu; the evaluations of mass distribution data from 252 Cf spontaneous fission, prompt and delayed neutron yields for 233 U; the studies for level width broaden effect; benchmark testing calculation for 232 Th; establishment of file-6 of n+ 12 C for CENDL-3 et al. (authors)

Progress in small angle neutron scattering activities in Malaysia

International Nuclear Information System (INIS)

Abdul Aziz Bin Mohamed; Azali Bin Muhamad; Shukri Bin Mohd

1999-01-01

The current status of SANS (Small Angle Neutron Scattering facility) activities in Malaysia has been presented. Many works need to be done for system improvement before the system can be confidently used as one of effective quality control tools in materials production and engineering sectors. (author)

Progress report 1981

International Nuclear Information System (INIS)

Chalupka, A.; Dirninger, G.

1982-01-01

The progress report describes the scientific work and research results of the institute for radium research and nuclear physics of the Austrian Academy of Sciences for the period of 1981. The progress report covers the subject areas of nuclear theory, nuclear model calculations, experimental nuclear physics and neutron involved reactions, medium energy physics, instrumentation and detectors, evaluation of nuclear data and numerical data processing, dating, applications in medicine, dosimetry and environmental studies. A list of publications of this institute is given. (A.N.)

Progress report 1982

International Nuclear Information System (INIS)

Chalupka, A.; Wild, E.; Dirninger, G.

1983-01-01

The progress report describes the scientific work and research results of the institute for radium research and nuclear physics of the Austrian Academy of Sciences for the period of 1982. The progress report covers the subject areas of nuclear theory, nuclear model calculations, experimental nuclear physics and neutron involved reactions, medium energy physics, instrumentation and detectors, evaluation of nuclear data and numerical data processing, dating, applications in medicine, dosimetry and environmental studies. A list of publications of this institute is given. (A.N.)

Experimental Physics Division of the Los Alamos Project. Progress report No. 4

Energy Technology Data Exchange (ETDEWEB)

1943-09-01

Included in this semi-monthly report written in 1943 are progress with neutron beams, neutron absorption in enriched materials, equipment operation and maintenance reports of the cyclotron neutron source facility, and instrumentation maintenance activities of individuals in the cyclotron group. (GHT)

Cumulative particle production in the quark recombination model

International Nuclear Information System (INIS)

Gavrilov, V.B.; Leksin, G.A.

1987-01-01

Production of cumulative particles in hadron-nuclear inteactions at high energies is considered within the framework of recombination quark model. Predictions for inclusive cross sections of production of cumulative particles and different resonances containing quarks in s state are made

LANSCE '90: the Manuel Lujan Jr. Neutron Scattering Center

International Nuclear Information System (INIS)

Pynn, Roger

1991-01-01

This paper describes progress that has been made at the Manuel Lujan Jr. Neutron Scattering Center (LANSCE) during the past two years. Presently, LANSCE provides a higher peak neutron flux than any other pulsed spallation neutron source. There are seven spectrometers for neutron scattering experiments that are operated for a national user program sponsored by the U.S. Department of Energy. Two more spectrometers are under construction. Plans have been made to raise the number of beam holes available for instrumentation and to improve the efficiency of the target/moderator system. (author)

LANSCE '90: The Manuel Lujan Jr. Neutron Scattering Center

International Nuclear Information System (INIS)

Pynn, R.

1990-01-01

This paper describes progress that has been made at the Manuel Lujan Jr. Neutron Scattering Center (LANSCE) during the past two years. Presently, LANSCE provides a higher peak neutron flux than any other pulsed spallation neutron source. There are seven spectrometers for neutron scattering experiments that are operated for a national user program sponsored by the US Department of Energy. Two more spectrometers are under construction. Plans have been made to raise the number of beam holes available for instrumentation and to improve the efficiency of the target/moderator system. 9 refs., 4 figs

Neutron imaging plates

International Nuclear Information System (INIS)

Niimura, Nobuo

1995-01-01

Imaging plates have been used in the field of medical diagnosis since long ago, but their usefulness was verified as the two-dimensional detector for analyzing the X-ray crystalline structure of high bio molecules like protein, and they have contributed to the remarkable progress in this field. The great contribution is due to the excellent features, such as the detection efficiency of about 100%, the positional resolution smaller than 0.2 mm, the dynamic range of five digits, and the area of several hundreds mm square. The neutron imaging plates have not yet obtained the sufficient results. It was planned to construct the neutron diffractometer for biological matters, and to put imaging plate neutron detectors (IP-ND) to practical use as the detector. The research on the development of IP-NDs was carried out, and the IPp-NDs having the performance comparable with that for X-ray were able to be produced. Imaging plates are the integral type two-dimensional radiation detector using photostimulated luminescence matters, and their principle is explained. As to neutron imaging plates, the converter, neutron detection efficiency and the flight of secondary particles in photo-stimulated luminescence matters are described. As for the present state of development of neutron imaging plates, the IP-NDs made for trial, the dynamic range, the positional resolution, the detection efficiency and the kinds of converters, and the application of IP-NDs are reported. (K.I.)

Directed Neutron Beams From Inverse Kinematic Reactions

Science.gov (United States)

Vanhoy, J. R.; Guardala, N. A.; Glass, G. A.

2011-06-01

Kinematic focusing of an emitted fairly mono-energetic neutron beam by the use of inverse-kinematic reactions, i.e. where the projectile mass is greater than the target atom's mass, can provide for the utilization of a significant fraction of the fast neutron yield and also provide for a safer radiation environment. We examine the merit of various neutron production reactions and consider the practicalities of producing the primary beam using the suitable accelerator technologies. Preliminary progress at the NSWC-Carderock Positive Ion Accelerator Facility is described. Possible important applications for this type of neutron-based system can be both advanced medical imaging techniques and active "stand-off" interrogation of contraband items.

Recent Developments in GEM-Based Neutron Detectors

International Nuclear Information System (INIS)

Saenboonruang, K.

2014-01-01

The gas electron multiplier (GEM) detector is a relatively new gaseous detector that has been used for less than 20 years. Since the discovery in 1997 by F. Sauli, the GEM detector has shown excellent properties including high rate capability, excellent resolutions, low discharge probability, and excellent radiation hardness. These promising properties have led the GEM detector to gain popularity and attention amongst physicists and researchers. In particular, the GEM detector can also be modified to be used as a neutron detector by adding appropriate neutron converters. With properties stated above and the need to replace the expensive 3 He-based neutron detectors, the GEM-based neutron detector will be one of the most powerful and affordable neutron detectors. Applications of the GEM-based neutron detectors vary from researches in nuclear and particle physics, neutron imaging, and national security. Although several promising progresses and results have been shown and published in the past few years, further improvement is still needed in order to improve the low neutron detection efficiency (only a few percent) and to widen the possibilities for other uses.

Progress report of CJD

International Nuclear Information System (INIS)

2002-01-01

This paper is the progress report of the Russian Nuclear Data Center at F.E.I., Obninsk. Evaluations have been made for dosimetry reactions and neutron reactions. Analysis of the spectra and the production cross sections were made. (a.n.)

Neutron beam facilities at the Australian Replacement Research Reactor

International Nuclear Information System (INIS)

Kennedy, Shane; Robinson, Robert; Hunter, Brett

2001-01-01

Australia is building a research reactor to replace the HIFAR reactor at Lucas Heights by the end of 2005. Like HIFAR, the Replacement Research Reactor will be multipurpose with capabilities for both neutron beam research and radioisotope production. It will be a pool-type reactor with thermal neutron flux (unperturbed) of 4 x 10 14 n/cm 2 /sec and a liquid D 2 cold neutron source. Cold and thermal neutron beams for neutron beam research will be provided at the reactor face and in a large neutron guide hall. Supermirror neutron guides will transport cold and thermal neutrons to the guide hall. The reactor and the associated infrastructure, with the exception of the neutron beam instruments, is to be built by INVAP S.E. under contract. The neutron beam instruments will be developed by ANSTO, in consultation with the Australian user community. This status report includes a review the planned scientific capabilities, a description of the facility and a summary of progress to date. (author)

International Seminar on Advanced Pulsed Neutron Sources PANS-II. Invited talks

International Nuclear Information System (INIS)

Pepelyshev, Yu.N.

1994-01-01

A conceptual design of creating intense pulsed neutron sources based on high-current accelerators and pulsed reactors for neutron scattering experiments is considered. The progress in high-efficiency moderator developments is shown. Results of diffraction studied are presented

Preliminary design of GDT-based 14 MeV neutron source

International Nuclear Information System (INIS)

Du Hongfei; Chen Dehong; Wang Hui; Wang Fuqiong; Jiang Jieqiong; Wu Yican; Chen Yiping

2012-01-01

To meet the need of D-T fusion neutron source for fusion material testing, design goals were presented in this paper according to the international requirements of neutron source for fusion material testing. A preliminary design scheme of GDT-based 14 MeV neutron source was proposed, and a physics model of the neutron source was built based on progress of GDT experiments. Two preliminary design schemes (i. e. FDS-GDT1, FDS-GDT2) were designed; among which FDS-GDT2 can be used for fusion material testing with neutron first wall loading of 2 MW/m 2 . (authors)

Communication of nuclear data progress: No.15 (1996)

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-06-01

Communication of Nuclear Data Progress (CNDP) is set up by Chinese Nuclear DATA Center. This is the 15th issue. The nuclear data achievements and progress in China during the last year are presented. It mainly includes: the measurements of the energy spectrum and angular distributions of protons from stainless steel bombarded by 14.6 MeV neutrons, theoretical calculations of {sup 59}Co and {sup 90}Zr neutron reaction data, the method and program CABEI for adjusting consistency between natural and its isotope data, {sup 58,60,61,62,64,Nat}Ni(n, p), {sup 59}Co, {sup 90}Zr(n,x) and {sup 84}Rb decay data, the status of CENDL-2.1 and progress on Chinese Evaluated Nuclear Parameter Library.

Progress Towards an Indirect Neutron Capture Capability at LANSCE

Energy Technology Data Exchange (ETDEWEB)

Koehler, Paul E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ullmann, John Leonard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Couture, Aaron Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mosby, Shea Morgan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-09-20

There are many neutron-capture cross sections of importance to radiochemical diagnostics and nuclear forensics which are beyond the reach of direct measurements. Hence, we have been developing an apparatus on flight path (FP) 13 at target 1 at LANSCE for tightly constraining these cross sections via determination of the underlying physical quantities. FP-13 was initially a cold-neutron beam line for materials science and therefore required substantial modification for use for nuclear physics. In FY17, we made several improvements to FP-13, demonstrated improved performance due to these changes via measurements on a variety of samples, identified a few more needed improvements, and reconfigured the beam line to implement the most important of these. New measurements to assess the impact of the most recent improvement will commence when beam is restored to LANSCE. Although FP-13 has not yet reached the performance required for small radioactive samples, measurements on a gold sample have led to an important science result which we are preparing for publication.

Neutron radiography at the SCK/CEN

International Nuclear Information System (INIS)

Tourwe, H.

1977-01-01

Neutron radiography has become in recent years a very important method of nondestructive testing in industry and research. The earliest practical application of neutron radiography has probably been the inspection of highly radioactive material: originally irradiated reactor fuels. Applications then progressed to other nuclear and industrial inspection problems. Neutron radiography and the conventional X-ray or gamma techniques are complementary. Some of the most important application fields of neutron radiography are: the detection of light elements (H, Li, B,...) with a very high scattering of absorption cross section for thermal neutrons; the nondestructive control of fuel before and after irradiation; controls where a distinction has to be made between isotopes of the same element ( 235 U and 238 U, 10 B and 11 B,...) and between components of a similar atomic number (Fe and Zn); the control of materials with a high density; the study of corrosion in closed structures; the control of the homogeneity of foreign materials in alloys,.... (author)

Progress report April 1, to June 30, 1956. Physics Division

Energy Technology Data Exchange (ETDEWEB)

NONE

1956-07-01

This is a progress report of the Physics Division at Chalk River Nuclear Laboratories from April 1, to June 30, 1956. It describes the research in nuclear physics, general physics; theoretical physics and electronics. The research areas covered in this report include nuclear reactions, nuclear decay, neutron capture gamma ray spectra, NRX production of plutonium and its higher isotopes, slow neutron spectrometry, neutron diffraction, gamma ray crystal spectrometry, theory of binary fission and analysis of neutron scattering data.

Progress report April 1, to June 30, 1956. Physics Division

International Nuclear Information System (INIS)

1956-01-01

This is a progress report of the Physics Division at Chalk River Nuclear Laboratories from April 1, to June 30, 1956. It describes the research in nuclear physics, general physics; theoretical physics and electronics. The research areas covered in this report include nuclear reactions, nuclear decay, neutron capture gamma ray spectra, NRX production of plutonium and its higher isotopes, slow neutron spectrometry, neutron diffraction, gamma ray crystal spectrometry, theory of binary fission and analysis of neutron scattering data.

Intense neutron irradiation facility for fusion reactor materials

Energy Technology Data Exchange (ETDEWEB)

Noda, Kenji; Oyama, Yukio; Kato, Yoshio; Sugimoto, Masayoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1997-03-01

Technical R and D of d-Li stripping type neutron irradiation facilities for development of fusion reactor materials was carried out in Fusion Materials Irradiation Test Facility (FMIT) project and Energy Selective Neutron Irradiation Test Facility (ESNIT) program. Conceptual design activity (CDA) of International Fusion Materials Irradiation Facility (IFMIF), of which concept is an advanced version of FMIT and ESNIT concepts, are being performed. Progress of users` requirements and characteristics of irradiation fields in such neutron irradiation facilities, and outline of baseline conceptual design of IFMIF were described. (author)

Progress in neutron beam development at the HFR Petten (feasibility study for a BNCT facility)

International Nuclear Information System (INIS)

Constantine, G.; Moss, R.L.; Watkins, P.R.D.; Perks, C.A.; Delafield, H.J.; Ross, D.; Voorbraak, W.P.; Paardekooper, A.; Freudenreich, W.E.; Stecher-Rasmussen, F.

1990-08-01

Boron Neutron Capture Therapy, using intermediate energy neutrons to achieve the deep penetration essential for treating brain tumours, can be implemented with a filtered reactor neutron beam. This is designed to minimize the mean energy of the neutrons to keep proton recoil damage to the scalp within normal tissue tolerance limits whilst delivering the required thermal neutron fluence to the tumour over a reasonably short period. This can only be realized in conjunction with a high power density reactor. At the Joint Research Centre Petten an optimized neutron filter is currently being built for installation into the HB11 beam tube of the High Flux Reactor HFR. Part of the development leading to this design has been an extensive study of broad spectrum, filtered beam performance on the HB7 beam tube facility. A wide range of calculations was performed using the Monte Carlo code, MCPN, supported by validation experiments in which several filter configuration incorporating aluminium, sulphur, liquid argon, titanium and cadmium were installed for low power measurements of the neutron fluence rate, neutron spectra and beam gamma-ray contamination. The measurements were carried out within a successful European collaboration. Evaluations were made of the reactor core edge and unfiltered beam spectra, for comparison with MCNP calculations. Multi-foil activation methods and also gamma dose determination in the filtered beam using thermo-luminescent detectors were performed by the ECN. The Harwell/ Birmingham University collaborators undertook the neutron spectrum measurements in the filtered beam. proton recoil spectrometry was used above 30 keV, combined with a multi-sphere and BF 3 chamber response modification technique. Subsequent spectrum adjustment was carried out with the SENSAK code. The agreement between the calculated and measured spectra has given confidence in the reactor and filter modelling methods used to design the HB11 therapy facility. (author). 12 refs

Neutron cross section measurements using the ORELA: the stable tellurium isotopes (n,γ), 238U(n,n'), 232Th(n,n'), 187Os(n,n'), 186187188Os(n,nn'γ), and 205Tl(n,nγ). Progress report, September 1, 1980-September 1, 1981

International Nuclear Information System (INIS)

Winters, R.R.

1981-08-01

Progress on the following subjects is reviewed: (1) high resolution neutron cross sections and the optical model potential, (2) renormalization of neutron capture cross sections, and (3) measurement of the argon 40 total cross section

Applying virtual and augmented reality in cultural computing

NARCIS (Netherlands)

Bartneck, C.; Hu, J.; Salem, B.I.; Cristescu, R.; Rauterberg, G.W.M.

2008-01-01

We are exploring a new application of virtual and augmented reality for a novel direction in human-computer inteaction named 'cultural computing', which aims to provide a new medium for cultural translation and unconscious metamorphosis. In this application both virtual and robotic agents are

On the mechanism of fission neutron emission

International Nuclear Information System (INIS)

Maerten, H.; Richter, D.; Seeliger, D.

1986-01-01

This review represents the present knowledge of the mechanism of prompt fission neutron emission. Starting with a brief fission process characterization related with neutron emission, possible emission mechanisms are discussed. It is emphasized that the experimental study of special mechanisms, i.e. scission neutron emission processes, requires a sufficiently correct description of emission probabilities on the base of the main mechanism, i.e. the evaporation from fully accelerated fragments. Adequate statistical-model approaches have to account for the complexity of nuclear fission reflected by an intricate fragment distribution. The present picture of scission neutron emission is not clarified neither experimentally nor theoretically. Deduced data are contradictory and depend on the used analysis procedures often involving rough discriptions of evaporated-neutron distributions. The contribution of two secondary mechanisms of fission neutron emission, i.e. the neutron evaporation during fragment acceleration and neutron emission due to the decay of 5 He after ternary fission, is estimated. We summarize the recent progress of the theoretical description of fission neutron spectra in the framework of statistical models considering the standard spectrum of 252 Cf(sf) neutrons especially. The main experimental basis for the study of fission neutron emission is the accurate measurement of emission probabilities as a function of emission energy and angle (at least) as well as fragment parameters (mass number ratio and kinetic energy). The present status is evaluated. (author)

Development of a neutron converter for studies of neutron-induced fission fragments at the IGISOL facility

CERN Document Server

Lantz, M; Al-Adili, A; Jokinen, A; Kolhinen, V; Mattera, A; Rinta-Antila, S; Penttilä, H; Pomp, S; Rakoupoulos, V; Simutkin, V; Solders, A

2014-01-01

The ERINDA funded scientific visit has enabled the groups at U ppsala Uni- versity and University of Jyväskylä to work closer together on the design of a neutron converter that will be used as neutron source in fissi on yield studies at the IGISOL-JYFLTRAP facility at the University of Jyväsk ylä. The design is based on simulations with both deterministic codes and Mo nte Carlo codes, and an ERINDA funded benchmark measurement. In order to obta in a com- petitive count rate the fission targets will be placed very cl ose to the neutron converter. The intention is to have a flexible design that wil l enable neutron fields with different energy distributions. In this report t he progression and the present status of the design work will be discussed, togethe r with an outlook of the future plans

Forensic neutron activation analysis - the Japanese scene

International Nuclear Information System (INIS)

Kishi, Tohru.

1986-01-01

The progress of forensic neutron activation analysis/FNAA/ in Japan is described. FNAA began in 1965 and during the past 20 years many cases have been handled; these include determination of toxic materials, comparison examination of physical evidences /e.g.,paints, metal fragments, plastics and inks/ and drug sample differenciation. Neutron activation analysis is applied routinely to the scientific criminal investigation as one of multielement analytical techniques. This paper also discusses these routine works. (author)

Multidisk neutron velocity selectors

International Nuclear Information System (INIS)

Hammouda, B.

1992-01-01

Helical multidisk velocity selectors used for neutron scattering applications have been analyzed and tested experimentally. Design and performance considerations are discussed along with simple explanation of the basic concept. A simple progression is used for the inter-disk spacing in the 'Rosta' design. Ray tracing computer investigations are presented in order to assess the 'coverage' (how many absorbing layers are stacked along the path of 'wrong' wavelength neutrons) and the relative number of neutrons absorbed in each disk (and therefore the relative amount of gamma radiation emitted from each disk). We discuss whether a multidisk velocity selector can be operated in the 'reverse' configuration (i.e. the selector is turned by 180 0 around a vertical axis with the rotor spun in the reverse direction). Experimental tests and calibration of a multidisk selector are reported together with evidence that a multidisk selector can be operated in the 'reverse' configuration. (orig.)

Advanced Neutron Source (ANS) Project progress report, FY 1994

Energy Technology Data Exchange (ETDEWEB)

Campbell, J.H.; King-Jones, K.H. [eds.; Selby, D.L.; Harrington, R.M. [Oak Ridge National Lab., TN (United States); Thompson, P.B. [Martin Marietta Energy Systems, Inc., Oak Ridge, TN (United States). Central Engineering Services

1995-01-01

The President`s budget request for FY 1994 included a construction project for the Advanced Neutron Source (ANS). However, the budget that emerged from the Congress did not, and so activities during this reporting period were limited to continued research and development and to advanced conceptual design. A significant effort was devoted to a study, requested by the US Department of Energy (DOE) and led by Brookhaven National Laboratory, of the performance and cost impacts of reducing the uranium fuel enrichment below the baseline design value of 93%. The study also considered alternative core designs that might mitigate those impacts. The ANS Project proposed a modified core design, with three fuel elements instead of two, that would allow operation with only 50% enriched uranium and use existing fuel technology. The performance penalty would be 15--20% loss of thermal neutron flux; the flux would still just meet the minimum design requirement set by the user community. At the time of this writing, DOE has not established an enrichment level for ANS, but two advisory committees have recommended adopting the new core design, provided the minimum flux requirements are still met.

Advanced Neutron Source (ANS) Project progress report, FY 1994

International Nuclear Information System (INIS)

Campbell, J.H.; King-Jones, K.H.; Thompson, P.B.

1995-01-01

The President's budget request for FY 1994 included a construction project for the Advanced Neutron Source (ANS). However, the budget that emerged from the Congress did not, and so activities during this reporting period were limited to continued research and development and to advanced conceptual design. A significant effort was devoted to a study, requested by the US Department of Energy (DOE) and led by Brookhaven National Laboratory, of the performance and cost impacts of reducing the uranium fuel enrichment below the baseline design value of 93%. The study also considered alternative core designs that might mitigate those impacts. The ANS Project proposed a modified core design, with three fuel elements instead of two, that would allow operation with only 50% enriched uranium and use existing fuel technology. The performance penalty would be 15--20% loss of thermal neutron flux; the flux would still just meet the minimum design requirement set by the user community. At the time of this writing, DOE has not established an enrichment level for ANS, but two advisory committees have recommended adopting the new core design, provided the minimum flux requirements are still met

IPEN's Nuclear Physics and Chemistry Department - Progress report - 1995-1996

International Nuclear Information System (INIS)

1997-01-01

The biannual progress report of 1995-1996 of IPEN's Nuclear Physics and Chemistry Department - Brazilian organization - introduces the next main topics: neutron activation and radiochemical analysis; nuclear structure and reactions; neutron diffraction; hyperfine interactions; applied physics and instrumentation; publications; academic activities; services; and personnel

IPEN's Nuclear Physics and Chemistry Department - Progress report - 1995-1996

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-07-01

The biannual progress report of 1995-1996 of IPEN's Nuclear Physics and Chemistry Department - Brazilian organization - introduces the next main topics: neutron activation and radiochemical analysis; nuclear structure and reactions; neutron diffraction; hyperfine interactions; applied physics and instrumentation; publications; academic activities; services; and personnel.

Neutron detection using superheated drops. Progress report, 1 May 1981-15 November 1982

International Nuclear Information System (INIS)

Apfel, R.E.

1981-11-01

The goal of this research has been to determine whether neutron detectors based on superheated drops not only have the characteristics desirable for neutron dosimetry (sensitivity and energy response, etc.) but also have the practical attributes (stability and ease of handling) which warrant later commercial development. Initial experiments with five materials (Freons 12, 114, 142B, and isobutane and cis-2-butene) indicate threshold neutron energies ranging from thermal to 5 MeV depending on the material, and an energy response which follows the general shape of the dose equivalent response of the body as set forth by the Commission on Radiological Protection (ICRP). This indicates that one can choose a drop material to meet a wide variety of objectives

Neutron interactions with biological tissue. Progress report, December 1, 1993--November 30, 1994

International Nuclear Information System (INIS)

1994-01-01

An attempt is made to obtain information about the physical stage of neutron interactions with tissue through secondary charged particles. The authors use theoretical calculations whose input includes neutron cross section data; range, stopping power, ion yield, and straggling information; and geometrical properties. Outputs are initial and slowing-down spectra of charged particles, kerma factors, average values of quality factors, microdosimetric spectra, and integral microdosimetric parameters such as bar y F , bar y D , y * . Since it has become apparent that nanometer site sizes are more relevant to radiobiological effects, the calculations of event size spectra and their parameters have been extended to these smaller diameters. This information is basic to radiological physics, radiation biology, radiation protection of workers, and standards for neutron dose measurement

Characterization of the Ljubljana TRIGA thermal column neutron radiographic facility

International Nuclear Information System (INIS)

Nemec, T.; Rant, J.; Kristof, E.; Glumac, B.

1995-01-01

An extensive characterization of the neutron beam of the existing neutron radiographic facility in the thermal column of the Ljubljana Triga Mark II research reactor is in progress. Neutron beam characteristics are needed to determine the effect of various neutron and gamma radiation on the neutron radiographic image. Commercially available medical scintillator converter screens based on Gd dioxy sulphite as well as Gd metal neutron converters are used to record neutron radiographic image. Thermal, epithermal and fast neutron fluxes were measured using Au and In activation detectors and cadmium ratio is determined. Neutron beam flux profiles are measured by film densitometry and by Au activation detector wires. By exposing films shielded by boral or lead plates individual contributions of thermal, epithermal neutrons and gamma radiation are estimated by densitometric measurements. By recording images of neutron image quality indicators BPI (Beam Purity Indicator) and SI (Sensitivity Indicator) produced by Riso, standard neutron radiography image characteristic are established. In gamma dosimetric measurements thermoluminescent detectors (CaF 2 Mn) are used. (author)

ORION, a multipurpose detector for neutrons. Some new developments

International Nuclear Information System (INIS)

Perier, Y.; Lienard, E.; Lott, B.; Galin, J.; Morjean, M.; Peghaire, A.; Quednau, B.; El Masri, Y.; Keutgen, Th.; Tilquin, I.

1996-01-01

Different properties of the four-pi neutron detector ORION have been tested: its efficiency in both modes, fast and delayed, its time resolution and position sensitivity. For the later test, the impact of the neutron beam onto the detector was varied by sliding it, perpendicular to the beam direction. All the presented data are tentative with the analysis still in progress. (K.A.)

Evaluation and calculation of neutron transactinide cross-sections

International Nuclear Information System (INIS)

Konshin, V.A.

1980-01-01

This paper reviews the state of the art of nuclear theory and its application to the evaluation and calculation of neutron reaction cross sections of transactinium isotopes. In particular, the paper describes the current evaluation of the total files of neutron reaction data for 240 Pu and 241 Pu in the energy range between 10 -5 eV and 15 MeV based on a thorough analysis of available experimental data and on the use of modern theoretical concepts, and the work in progress on the evaluation of the total neutron reaction data file for 242 Pu and 241 Am. (author)

Electron volt neutron spectrometers

International Nuclear Information System (INIS)

Pietropaolo, A.; Senesi, R.

2011-01-01

The advent of pulsed neutron sources has made available intense fluxes of epithermal neutrons (500 meV ≤E≤100 eV ). The possibility to open new investigations on condensed matter with eV neutron scattering techniques, is related to the development of methods, concepts and devices that drive, or are inspired by, emerging studies at this energy scale. Electron volt spectrometers have undergone continuous improvements since the construction of the first prototype instruments, but in the last decade major breakthroughs have been accomplished in terms of resolution and counting statistics, leading, for example, to the direct measurement of the proton 3-D Born–Oppenheimer potential in any material, or to quantitatively probe nuclear quantum effects in hydrogen bonded systems. This paper reports on the most effective methods and concepts for energy analysis and detection, as well as devices for the optimization of electron volt spectrometers for different applications. This is set in the context of the progress made up to date in instrument development. Starting from early stages of development of the technique, particular emphasis will be given to the Vesuvio eV spectrometer at the ISIS neutron source, the first spectrometer where extensive scientific, as well as research and development programmes have been carried out. The potential offered by this type of instrumentation, from single particle excitations to momentum distribution studies, is then put in perspective into the emerging fields of eV spectroscopy applied to cultural heritages and neutron irradiation effects in electronics. - Highlights: ► Neutron spectrometers at eV energies. ► Methods and techniques for eV neutrons counting at spallation sources. ► Scattering, imaging and radiation hardness tests with multi-eV neutrons.

Neutron scattering equipments in JAERI. Current status

International Nuclear Information System (INIS)

Hamaguchi, Yoshikazu; Minakawa, Nobuaki

2003-01-01

24 neutron scattering instruments are installed in the JRR-3M research reactor. Among them JAERI has 12 neutron scattering instruments. Those instruments are HRPD for high-resolution structural analysis, TAS-1 and TAS-2 for elastic and inelastic scattering and for magnetic scattering measurements by the polarized neutron, LTAS for elastic and inelastic scattering measurement at a low energy region, and for neutron device development, PNO for topography and for very small angle scattering measurement in a small Q range, NRG for neutron radiography, RESA for internal strain measurements, SANS for the molecule and semi-macroscopic magnetic structural analysis, BIX-2 and BIX-3 for the biological structural analysis research, and PGA for the research of prompt gamma-ray analysis. The university groups have 12 neutron scattering instruments. Since those instruments were installed at the period when JRR-3M was completed, about 10 years have passed. In order to match the old control systems with the progress of recent computer technologies, and peripheral equipment, numbers of instruments are being renewed. In the neutron guide hall of JRR-3M, the Ni mirror guide tube was replaced by a super mirror guide tube to increase neutron flux. The intensity of 2A flux was increased by a factor of about two. (J.P.N.)

Neutron spectrum measurement by TOF

International Nuclear Information System (INIS)

Aizawa, Otohiko

1982-01-01

The TOF experiments by using various facilities are described. The steady neutron spectra in light water which contains non-1/V absorbing materials were measured by the TOF method at a LINAC facility. The results were compared with the calculations based on the Koppel-Haywood model and two others. The leakage neutron spectra from a heavy-water assembly were measured and compared with model calculations. The time-dependent energy spectra in a small graphite assembly were measured. For this measurement, a chopper system was also used. The two-region calculation explains the spectrum just after the neutron burst. The time-dependent spectra in a small Be assembly and in an assembly of coolant-moderator containing hydrogen were also measured. The calculations based on various models are in progress. The TOF experiments at the reactor-chopper facility were carried out for measuring the total cross sections of crystalline moderators, the thermal neutron total cross section of high temperature beryllium, the thermal neutron total cross sections of granular lead and high temperature liquid lead, and the angle-dependent scattering spectra. A pseudo-chopper was designed and constructed. The spectra of the neutron field for medical use were measured by the chopper-TOF system. The thermal neutron total cross sections of Fe, Zr, Nb and Mg were measured, and the results were compared with the calculations by THRUSH and UNCLE-TOM codes. The random-trigger TOF experiments were made by using Cf-252. (Kato, T.)

Neutron beam measurement dosimetry

International Nuclear Information System (INIS)

Amaro, C.R.

1995-01-01

This report describes animal dosimetry studies and phantom measurements. During 1994, 12 dogs were irradiated at BMRR as part of a 4 fraction dose tolerance study. The animals were first infused with BSH and irradiated daily for 4 consecutive days. BNL irradiated 2 beagles as part of their dose tolerance study using BPA fructose. In addition, a dog at WSU was irradiated at BMRR after an infusion of BPA fructose. During 1994, the INEL BNCT dosimetry team measured neutron flux and gamma dose profiles in two phantoms exposed to the epithermal neutron beam at the BMRR. These measurements were performed as a preparatory step to the commencement of human clinical trials in progress at the BMRR

Neutron Research in HANARO

International Nuclear Information System (INIS)

Kim, Hark Rho

2005-01-01

HANARO (High-flux Advanced Neutron Application Reactor), which was designed and constructed by indigenous technology, is a world-class multi-purpose research reactor with a design thermal power of 30 MW, providing high neutron flux for various applications in Korea. HANARO has been operated since its first criticality in February 1995, and is now successfully utilized in such areas as neutron beam research, fuel and materials tests, radioisotopes and radiopharmaceuticals production, neutron activation analysis, and neutron transmutation doping, etc. A number of experimental facilities have been developed and installed since the beginning of reactor operation, and R and D activities for installing more facilities are actively under progress. Three flux traps in the core (CT, IR1, IR2), providing a high fast neutron flux, can be used for materials and fuel irradiation tests. They are also proper for production of high specific activity radioisotopes. Four vertical holes in the outer core region, abundant in epithermal neutrons, are used for fuel or material tests and radioisotope production. In the heavy water reflector region, 25 vertical holes with high quality thermal neutrons are located for radioisotope production, neutron activation analysis, neutron transmutation doping and cold neutron source installation. The two largest holes named NTD1 and NTD2 are for neutron transmutation doping, CNS for the cold neutron source installation, and LH for the irradiation of large targets. The high resolution powder diffractometer (HRPD) became operational in 1998, followed by the four circle diffractometer (FCD) in 1999, the residual stress instrument (RSI) in 2000, and the small angle neutron spectrometer (SANS) in 2001, respectively. HRPD and SANS became the most popular instruments these days, attracting wide range of users from academia, institutes and industries. We have made a lot of efforts during the last 10 years to develop some key components such as

Progress report 1981

International Nuclear Information System (INIS)

After giving a brief description of operations of an improvements to the University of Alberta nuclear physics facilities, this report summarizes the principal research programs. These include work on neutron scattering, thorium 232 fission, iodine 123 production. Progress towards the construction of MARIA, the Medical Accelerator Research Institute in Alberta, is described, and research on relativistic heavy ions is summarized

Progress report on neutron activation analysis at Dalat Nuclear Research Reactor

Energy Technology Data Exchange (ETDEWEB)

Tuan, Nguyen Ngoc [Nuclear Research Institute, Dalat (Viet Nam)

2003-03-01

Neutron Activation Analysis (NAA) is one of most powerful techniques for the simultaneous multi-elements analysis. This technique has been studied and applied to analyze major, minor and trace elements in Geological, Biological and Environmental samples at Dalat Nuclear Research Reactor. At the sixth Workshop, February 8-11, 1999, Yojakarta, Indonesia we had a report on Current Status of Neutron Activation Analysis using Dalat Nuclear Research Reactor. Another report on Neutron Activation Analysis at the Dalat Nuclear Research Reactor also was presented at the seventh Workshop in Taejon, Korea from November 20-24, 2000. So in this report, we would like to present the results obtained of the application of NAA at NRI for one year as follows: (1) Determination of the concentrations of noble, rare earth, uranium, thorium and other elements in Geological samples according to requirement of clients particularly the geologists, who want to find out the mineral resources. (2) The analysis of concentration of radionuclides and nutrient elements in foodstuffs to attend the program on Asian Reference Man. (3) The evaluation of the contents of trace elements in crude oil and basement rock samples to determine original source of the oil. (4) Determination of the elemental composition of airborne particle in the Ho Chi Minh City for studying air pollution. The analytical data of standard reference material, toxic elements and natural radionuclides in seawater are also presented. (author)

Progress report on neutron activation analysis at Dalat Nuclear Research Reactor

International Nuclear Information System (INIS)

Tuan, Nguyen Ngoc

2003-01-01

Neutron Activation Analysis (NAA) is one of most powerful techniques for the simultaneous multi-elements analysis. This technique has been studied and applied to analyze major, minor and trace elements in Geological, Biological and Environmental samples at Dalat Nuclear Research Reactor. At the sixth Workshop, February 8-11, 1999, Yojakarta, Indonesia we had a report on Current Status of Neutron Activation Analysis using Dalat Nuclear Research Reactor. Another report on Neutron Activation Analysis at the Dalat Nuclear Research Reactor also was presented at the seventh Workshop in Taejon, Korea from November 20-24, 2000. So in this report, we would like to present the results obtained of the application of NAA at NRI for one year as follows: (1) Determination of the concentrations of noble, rare earth, uranium, thorium and other elements in Geological samples according to requirement of clients particularly the geologists, who want to find out the mineral resources. (2) The analysis of concentration of radionuclides and nutrient elements in foodstuffs to attend the program on Asian Reference Man. (3) The evaluation of the contents of trace elements in crude oil and basement rock samples to determine original source of the oil. (4) Determination of the elemental composition of airborne particle in the Ho Chi Minh City for studying air pollution. The analytical data of standard reference material, toxic elements and natural radionuclides in seawater are also presented. (author)

Annual progress report 1988, operation of the high flux reactor

International Nuclear Information System (INIS)

1989-01-01

In 1988 the High Flux Reactor Petten was routinely operated without any unforeseen event. The availability was 99% of scheduled operation. Utilization of the irradiation positions amounted to 80% of the practical occupation limit. The exploitation pattern comprised nuclear energy deployment, fundamental research with neutrons, and radioisotope production. General activities in support of running irradiation programmes progressed in the normal way. Development activities addressed upgrading of irradiation devices, neutron radiography and neutron capture therapy

New development of neutron radiography with a small cyclotron

International Nuclear Information System (INIS)

Ikeda, Yasushi; Ohkubo, Kohei; Kato, Toshihiko; Nakamura, Tomihisa; Fuji, Takayoshi.

1990-01-01

A series of neutron radiography testing has been performed for several years by using a small accelerator called 'Baby Cyclotron' manufactured by Japan Steel Works, Ltd. The Baby Cyclotron produces fast neutrons at the rate of 4x10 12 n/cm 2 s, and enables to perform neutron radiography imaging by various techniques. The most important application of this Baby Cyclotron radiography system is the non-destructive testing (NDT) of various explosive devices prepared for space launch vehicles. It is assured that thermal neutron radiography testing is a very useful means for the NDT. Also fast neutron radiography testing is in progress. The fast neutron radiography with a CR39 track-etch image recorder was developed, and it was shown to be the very useful NDT means when the thicker objects used for new H-2 launch vehicles had to be examined. Because thermal neutron radiography has the high detectability of hydrogenous materials, organic elastomers such as O-rings and explosive powder are clearly observable through the opaque steel walls of containers. The Baby Cyclotron and the neutron radiography facility, thermal neutron and fast neutron radiography testings and so on are reported. (K.I.)

A measurement of the neutron lifetime by counting trapped protons

CERN Document Server

Snow, W M; Dewey, M S; Fei, X; Gilliam, D M; Greene, G L; Nico, J S; Wietfeldt, F E

2000-01-01

A measurement of the neutron lifetime tau sub n performed by trapping and counting decay protons from in-beam neutron decays in a Penning trap is in progress at the National Institute of Standards and Technology (NIST). A description of the measurement technique, the status of the data analysis, and prospects for improvements in the measurement are discussed.

Progress toward the development and testing of source reconstruction methods for NIF neutron imaging.

Science.gov (United States)

Loomis, E N; Grim, G P; Wilde, C; Wilson, D C; Morgan, G; Wilke, M; Tregillis, I; Merrill, F; Clark, D; Finch, J; Fittinghoff, D; Bower, D

2010-10-01

Development of analysis techniques for neutron imaging at the National Ignition Facility is an important and difficult task for the detailed understanding of high-neutron yield inertial confinement fusion implosions. Once developed, these methods must provide accurate images of the hot and cold fuels so that information about the implosion, such as symmetry and areal density, can be extracted. One method under development involves the numerical inversion of the pinhole image using knowledge of neutron transport through the pinhole aperture from Monte Carlo simulations. In this article we present results of source reconstructions based on simulated images that test the methods effectiveness with regard to pinhole misalignment.

Fission neutron output measurements at LANSCE

International Nuclear Information System (INIS)

Nelson, Ronald Owen; Haight, Robert C.; Devlin, Matthew J.; Fotiadis, Nikolaos; Laptev, Alexander; O'Donnell, John M.; Taddeucci, Terry N.; Tovesson, Fredrik; Ullmann, J.L.; Wender, Stephen A.; Bredeweg, T.A.; Jandel, M.; Vieira, D.J.; Wu, Ching-Yen; Becker, J.A.; Stoyer, M.A.; Henderson, R.; Sutton, M.; Belier, Gilbert; Chatillon, A.; Granier, Thierry; Laurent, Benoit; Taieb, Julien

2010-01-01

Accurate data for both physical properties and fission properties of materials are necessary to properly model dynamic fissioning systems. To address the need for accurate data on fission neutron energy spectra, especially at outgoing neutron energies below about 200 keV and at energies above 8 MeV, ongoing work at LANSCE involving collaborators from LANL, LLNL and CEA Bruyeres-le-Chatel is extending the energy range, efficiency and accuracy beyond previous measurements. Initial work in the outgoing neutron energy range from 1 to 7 MeV is consistent with current evaluations and provides a foundation for extended measurements. As part of these efforts, a new fission fragment detector that reduces backgrounds and improves timing has been designed fabricated and tested, and new neutron detectors are being assessed for optimal characteristics. Simulations of experimental designs are in progress to ensure that accuracy goals are met. Results of these measurements will be incorporated into evaluations and data libraries as they become available.

New perspectives from new generations of neutron sources

International Nuclear Information System (INIS)

Mezei, F.

2007-01-01

Since the early fifties the vital multidisciplinary progress in understanding condensed matter is, in a substantial fraction, based on results of neutron scattering experiments. Neutron scattering is an inherently intensity limited method and after 50 years of considerable advance - primarily achieved by improving the scattering instruments - the maturation of the technique of pulsed spallation sources now opens up the way to provide more neutrons with improved cost and energy efficiency. A quantitative analysis of the figure-of-merit of the specialized instruments for pulsed source operation shows that up to 2 orders of magnitude intensity gains can be achieved in the next decade, with the advent of high power spallation sources. The first stations on this road, the MW class short pulse spallation sources SNS in the Usa (under commissioning), and J-PARC in Japan (under construction) will be followed by the 5 MW long pulse European Spallation Source (ESS). Further progress, that can be envisaged on the longer term, could amount to as much as another factor of 10 improvement. (author)

New perspectives from new generations of neutron sources

Science.gov (United States)

Mezei, Ferenc

2007-09-01

Since the early 1950s the vital multidisciplinary progress in understanding condensed matter is, in a substantial fraction, based on results of neutron scattering experiments. Neutron scattering is an inherently intensity limited method and after 50 years of considerable advance—primarily achieved by improving the scattering instruments—the maturation of the technique of pulsed spallation sources now opens up the way to provide more neutrons with improved cost and energy efficiency. A quantitative analysis of the figure-of-merit of the specialized instruments for pulsed source operation shows that up to 2 orders of magnitude intensity gains can be achieved in the next decade, with the advent of high power spallation sources. The first stations on this road, the MW class short pulse spallation sources SNS in the USA (under commissioning), and J-PARC in Japan (under construction) will be followed by the 5 MW long pulse European Spallation Source (ESS). Further progress, that can be envisaged on the longer term, could amount to as much as another factor of 10 improvement. To cite this article: F. Mezei, C. R. Physique 8 (2007).

Physico-technical progress in neutron-capture therapy method

International Nuclear Information System (INIS)

Kanda, Keiji; Furubayashi, Toru; Aoki, Kazuhiko

1985-01-01

This paper describes mainly development studies on the determination method of in vivo 10 B for the purpose of employment for neutron capture therapy for malignant melanoma and other tumors. To darify the efficacy of the neutron capture therapy, it is necessary to determine 10 B concentration in the diseased part. This study aimed at in vivo 10 B concention determination in living sample to the level of ppm order with 10 % of analytical error within 1 hour, and these determination conditions were satified by prompt γ-ray (478 keV) determination of 10 B (n, αγ) 7 Li reaction. This method required no sample pretreatment. Further, data normalization by γ-ray of H(n, γ)D reaction permitted no disturbance by sample shape or size. Lower limit of detection of the proposed method was estimated in terms of measuring time and statistical error by the equations of 10 B concentration and error analysis derived by the authors. As for the effect of prompt γ-rays of 23 Na(n, γ) 24 Na and 6 Li(n, γ) 7 Li reactions, it was clarified that the former showed no disturbance but some correction was necessary in case of less than 0.1 g of smaple size owing to the latter reaction. In vivo sample determination showed the proposed method was practical. In this paper some results of phantom experiment for in vivo non-destructive 10 B measurement and related simulation calculation, and examination of effect of (γ, n) reaction in heavy water of biomedical irradiation equipment on radiation quality were also described. (Takagi, S.)

Report from the neutron diffraction work group

International Nuclear Information System (INIS)

1978-08-01

This progress report of the neutron diffraction group at the Hahn Meitner Institute in Berlin comprises the following contributions: Three-dimensional critical properties of CsNiF 3 around the Neel point; Spin waves in CsNiF 3 with an applied magnetic field; Solitons in CsNiF 3 : Their experimental evidence and their thermodynamics; Neutron diffraction study of DAG at very low temperatures and in external magnetic field; Neutron diffraction investigation of tricritical behaviour in DyPO 4 ; Crystalline modifications and structural phase transitions of NaOH; Gitterdynamik von Cerhydrid; Investigation of the ferroelectric-ferroelastic phase transition in KH 2 PO 4 and RbH 2 PO 4 by means of γ-ray diffractometry; A γ-ray diffractometer for systematic measurements of absolute structure factors; Electron density in pyrite by combined γ-ray and neutron diffraction measurements: Thermal parameters from short wavelength neutron data; Accurate determination of temperature parameters from neutron diffraction data: Direct observation of the thermal diffuse scattering from silicon using perfect crystals; A Compton spectrometer for momentum density studies using 412 keV γ-radiation; Investigation of the electronic structure of Niobiumhydrides by means of gamma-ray Compton scattering; Interpretation of Compton profile data in position space; High resolution neutron scattering measurements on single crystals using a horizontally bent monochromator and a multidetecter; Statistical analysis of neutron diffraction studies of proteins. (orig.) [de

Progress report 1971/72

International Nuclear Information System (INIS)

1972-01-01

The progress report comprises reports from interdisciplinary task groups on radiation protection, isotope application and radiation measurement technique, microscopy, linear accelerators, process computers, biophysics and nuclear physics. The last task group reports on work with the electron linear accelerator, nuclear spectroscopy, neutron physics, work with polarized particles, and experiments with the GSI heavy ion accelerator. (orig./AK) [de

Proceedings of 7th short conference on neutron radiography

International Nuclear Information System (INIS)

Hiraoka, Eiichi; Katsurayama, Kousuke; Tsujimoto, Tadashi

1986-10-01

The first short period conference on neutron radiography was held in 1970, and now the 7th meeting was held. The works to develop neutron radiography in Japan are as active as those in western countries, and the research is in progress by using neutrons from reactors, radioisotopes and accelerators in order to achieve the technology of high standard. In this conference, 26 papers and six comments were presented, and the themes covered the equipment for radiography, the practical application, and the related research. The second World Conference on Neutron Radiography will be held in Paris in June, 1986, and the further promotion of the spread of neutron radiography can be expected. The proceedings of the conference is published with the hope that joint effort and information exchange are further enhanced in coming years to develop the neutron radiography in Japan. The neutron radiography using the Kinki University reactor, the Rikkyo Triga-2 reactor, the Musashi reactor, the Kyoto research reactor, a 3MV Van de Graaff accelerator in Toyota, a subcompact cyclotron in Sumitomo, a baby cyclotron-dual collimator in National Space Development Agency and so on, Cf-252 based thermal neutron radiography, CT with Sb-124/Be neutrons, pulse power neutron source, imaging converters, neutron radiographic image processing, computed tomography using neutron television systems and others are reported. (Kako, I.)

Advisory Committee for the Calibration Standards of Ionizing Radiation Measurement: Section 3. Neutron measurements

International Nuclear Information System (INIS)

1982-01-01

Section III (Mesures neutroniques) of the Comite Consultatif pour les Etalons de Mesure des Rayonnements Ionisants held its fifth meeting in May 1981. Recent work carried out at BIPM in the field of neutron measurements was reported. The status of a full-scale 252 Cf neutron source intercomparison (10 7 s - 1 ) and of several restricted comparisons was discussed. Intercomparisons of fast neutron fluence rates are in progress ( 115 In(n,n') 115 Insup(m); NB/Zr) or will take place in the near future ( 115 n(n,#betta#) 116 Insup(m); 235 U and 238 U fission chambers). An intercomparison of neutron dosimetry standards by circulating tissue-equivalent ion chambers will be prepared and organized by BIPM. Finally, there was a broad exchange of information on work in progress at the various laboratories represented at the meeting [fr

Basic design of the HANARO cold neutron source using MCNP code

International Nuclear Information System (INIS)

Yu, Yeong Jin; Lee, Kye Hong; Kim, Young Jin; Hwang, Dong Gil

2005-01-01

The design of the Cold Neutron Source (CNS) for the HANARO research reactor is on progress. The CNS produces neutrons in the low energy range less than 5meV using liquid hydrogen at around 21.6 K as the moderator. The primary goal for the CNS design is to maximize the cold neutron flux with wavelengths of around 2 ∼ 12 A and to minimize the nuclear heat load. In this paper, the basic design of the HANARO CNS is described

Medical use of fast neutrons in radiotherapy and radiography

International Nuclear Information System (INIS)

Bewley, D.K.

1975-01-01

Over 400 patients have been treated with fast neutrons from a cyclotron at Hammersmith Hospital, London, using 16 MeV deuterons on beryllium. A large variety of malignant disease is included in this trial. A randomized trial of fast neutron therapy for cancer of the mouth and throat is in progress and preliminary results will be given. Fast neutron radiographs are often taken to check the positions of the fields used on the patients. These show no contrast from bone, but demonstrate only the presence of gas-filled cavities. As a diagnostic method, fast neutron radiography suffers from a number of disadvantages, the main ones being lack of sensitivity of the image-forming system and the hazard to the patient due to a large Quality Factor. Estimation of the absorbed dose given to different types of tissue is an important factor in the medical use of fast neutrons. More data are needed on the processes whereby fast neutrons impart energy to matter, particularly for neutrons above 15 MeV

Computational complexity in multidimensional neutron transport theory calculations. Progress report, September 1976--November 30, 1977

International Nuclear Information System (INIS)

Bareiss, E.H.

1977-08-01

The objectives of this research are to develop mathematically and computationally founded criteria for the design of highly efficient and reliable multidimensional neutron transport codes to solve a variety of neutron migration and radiation problems, and to analyze existing and new methods for performance

Progress report - Physics and Health Sciences - Physics Section - 1986 July 01 - December 31

International Nuclear Information System (INIS)

1987-02-01

This progress report of the Physics section of Chalk River Nuclear Laboratories highlights work on major equipment: 1) Tandem Accelerator Superconducting Cyclotron (TASCC), 2) Isotope Separator On Line (ISOL), 3) Spectrometer Array for Particles Produced in Heavy Ion Reactions (SAPPHIRE), and 4) The Double Neutron Spectrometer for neutron scattering (DUALSPEC). Theoretical physics work includes fractal theory, non-topological soliton model of the nucleons, meson currents in relativistic shell model theories and supergravity. Progress of the Sudbury Neutrino Observatory (SNO) and the National Fusion Program (NFP) is discussed. Two commercial aspects are included; the formation of Shar-Buc Enterprises, the first spin-off business of the Research Company and the Applied Neutron Diffraction for Industry (ANDI), a major commercial activity

Progress report

International Nuclear Information System (INIS)

Brumovsky, M.

1979-01-01

Progress Report, covering the period up to the end of 1979 year, was sent to the IAEA according to the research agreement No. 1971 /CF. This work covered the following fields: preparation and dummy irradiation experiments with a new experimental capsule of ''CHOUCA-M'' type; measurement of temperature fields and design of specimen holders; measurement of neutron energy spectrum in the irradiation place in our experimental reactor of VVR-S type (Nuclear Research Institute) using a set of activation detectors; unification and calibration of the measurement of neutron fluence with the use of Fe, Cu, Mn-Mg and Co-Al monitors; development and improvement of the measuring apparatus and technique for the dynamic testing of pre-cracked specimens with determination of dynamic parameters of fracture mechanics; preparation and manufacture of testing specimens from the Japanese steels - forging, plate and weld metal; preparation of the irradiation capsule for assembling

Calculations of neutron spectra after neutron-neutron scattering

Energy Technology Data Exchange (ETDEWEB)

Crawford, B E [Gettysburg College, Box 405, Gettysburg, PA 17325 (United States); Stephenson, S L [Gettysburg College, Box 405, Gettysburg, PA 17325 (United States); Howell, C R [Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Mitchell, G E [North Carolina State University, Raleigh, NC 27695-8202 (United States); Tornow, W [Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Furman, W I [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Lychagin, E V [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Muzichka, A Yu [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Nekhaev, G V [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Strelkov, A V [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Sharapov, E I [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Shvetsov, V N [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)

2004-09-01

A direct neutron-neutron scattering length, a{sub nn}, measurement with the goal of 3% accuracy (0.5 fm) is under preparation at the aperiodic pulsed reactor YAGUAR. A direct measurement of a{sub nn} will not only help resolve conflicting results of a{sub nn} by indirect means, but also in comparison to the proton-proton scattering length, a{sub pp}, shed light on the charge-symmetry of the nuclear force. We discuss in detail the analysis of the nn-scattering data in terms of a simple analytical expression. We also discuss calibration measurements using the time-of-flight spectra of neutrons scattered on He and Ar gases and the neutron activation technique. In particular, we calculate the neutron velocity and time-of-flight spectra after scattering neutrons on neutrons and after scattering neutrons on He and Ar atoms for the proposed experimental geometry, using a realistic neutron flux spectrum-Maxwellian plus epithermal tail. The shape of the neutron spectrum after scattering is appreciably different from the initial spectrum, due to collisions between thermal-thermal and thermal-epithermal neutrons. At the same time, the integral over the Maxwellian part of the realistic scattering spectrum differs by only about 6 per cent from that of a pure Maxwellian nn-scattering spectrum.

Progress in FMIT test assembly development

International Nuclear Information System (INIS)

Opperman, E.K.; Vogel, M.A.; Shen, E.J.; Trego, A.L.

1983-08-01

Research and development supporting the completed design of the Fusion Materials Irradiation Test (FMIT) Facility is continuing at the Hanford Engineering Development Laboratory (HEDL) in Richland, Washington. The FMIT, a deuteron accelerator based (d + Li) neutron source, will produce an intense flux of high energy neutrons for use in radiation damage studies of fusion reactor materials. The most intense flux magnitude of greater than 10 15 n/cm 2 -s is located close to the neutron producing lithium target and is distributed within a volume about the size of an American football. The conceptual design and development of FMIT experiments called Test Assemblies has progressed over the past five years in parallel with the design of the FMIT. The paper will describe the recent accomplishments made in developing test assemblies appropriate for use in the limited volume close to the FMIT target where high neutron flux and heating rates and the associated spacial gradients significantly impact design considerations

IPEN's Nuclear Physics and Chemistry Department - Progress report - 1995-1996

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-07-01

The biannual progress report of 1995-1996 of IPEN's Nuclear Physics and Chemistry Department - Brazilian organization - introduces the next main topics: neutron activation and radiochemical analysis; nuclear structure and reactions; neutron diffraction; hyperfine interactions; applied physics and instrumentation; publications; academic activities; services; and personnel.

Study of material science by neutron scattering

International Nuclear Information System (INIS)

Kim, H.J.; Yoon, B.K.; Cheon, B.C.; Lee, C.Y.; Kim, C.S.

1980-01-01

To develop accurate methods of texture measurement in metallic materials by neutron diffraction, (100),(200),(111) and (310) pole figures have been measured for the oriented silicon steel sheet, and currently study of correction methods for neutron absorption and extinction effects are in progress. For quantitative analysis of texture of polycrystalline material with a cubic structure, a software has been developed to calculate inverse pole figures for arbitrary direction specified in the speciman as well as pole figures for arbitrary chosen crystallographic planes from three experimental pole figures. This work is to be extended for the calculation of three dimensional orientation distribution function and for the evaluation of errors in the quantitative analysis of texture. Work is also for the study of N-H...O hydrogen bond in amino acid by observing molecular motions using neutron inelastic scattering. Measurement of neutron inelastic scattering spectrum of L-Serine is completed at 100 0 K and over the energy transfer range of 20-150 meV. (KAERI INIS Section)

Industrial and technological applications of neutrons

International Nuclear Information System (INIS)

Fontana, M.; Rustichelli, F.

1992-01-01

Owing to the construction of intense neutron sources and to the remarkable progress in acquisition and elaboration equipment, neutron scattering techniques have been employed more and more not only in basic research, but also in technological areas and for the solution of specific industrial problems. This is shown by the saturation of neutron beam time available at the main European sources and by an analysis of the users' distribution. Furthermore, the condensed-matter scientific community uses neutron scattering much more often now as a reference method and as an irreplaceable complement to other already well-established techniques. The aim of this Enrico Fermi course, on which the book is based, is to provide an up-to-date picture of the main results obtained (or obtainable) by means of neutron techniques in applied research. Emphasis is placed on the information and help these techniques can offer in some major areas of condensed-matter physics and materials science and to their possible developments in the near future. The volume is basically organized in topical subjects: for each one a brief introduction to the fundamentals is given, followed by examples of the concrete or potential applications. The first half deals mainly with applications of neutron scattering to materials science (metallurgy, magnetic materials, superconductors), while the second half mainly deals with polymers, micellar fluids, interfaces and liquid crystals

Accelerator-based epithermal neutron sources for boron neutron capture therapy of brain tumors.

Science.gov (United States)

Blue, Thomas E; Yanch, Jacquelyn C

2003-01-01

This paper reviews the development of low-energy light ion accelerator-based neutron sources (ABNSs) for the treatment of brain tumors through an intact scalp and skull using boron neutron capture therapy (BNCT). A major advantage of an ABNS for BNCT over reactor-based neutron sources is the potential for siting within a hospital. Consequently, light-ion accelerators that are injectors to larger machines in high-energy physics facilities are not considered. An ABNS for BNCT is composed of: (1) the accelerator hardware for producing a high current charged particle beam, (2) an appropriate neutron-producing target and target heat removal system (HRS), and (3) a moderator/reflector assembly to render the flux energy spectrum of neutrons produced in the target suitable for patient irradiation. As a consequence of the efforts of researchers throughout the world, progress has been made on the design, manufacture, and testing of these three major components. Although an ABNS facility has not yet been built that has optimally assembled these three components, the feasibility of clinically useful ABNSs has been clearly established. Both electrostatic and radio frequency linear accelerators of reasonable cost (approximately 1.5 M dollars) appear to be capable of producing charged particle beams, with combinations of accelerated particle energy (a few MeV) and beam currents (approximately 10 mA) that are suitable for a hospital-based ABNS for BNCT. The specific accelerator performance requirements depend upon the charged particle reaction by which neutrons are produced in the target and the clinical requirements for neutron field quality and intensity. The accelerator performance requirements are more demanding for beryllium than for lithium as a target. However, beryllium targets are more easily cooled. The accelerator performance requirements are also more demanding for greater neutron field quality and intensity. Target HRSs that are based on submerged-jet impingement and

Research within the coordinated programme on neutron scattering techniques in applied research

International Nuclear Information System (INIS)

Satya Murthy, N.S.

1982-02-01

This paper reviews developments of neutron scattering studies at Bhabha Atomic Research Centre (BARC) over the past two decades through utilisation of Apsara and Circus reactor facilities. Salient results in neutron crystallography, magnetic diffraction and inelastic neutron scattering will be presented highlighting progressive involvement in more and more complex studies. The growth of non-neutronic activities as a natural outcome of overall necessity and interest of investigators will be indicated. A description of facilities planned at R5 and the nature of studies that are likely to be taken up at R5 will be briefly discussed. (author)

Neutrons for science

International Nuclear Information System (INIS)

Jacrot, B.

2006-01-01

In 1967, France and Germany decided to cooperate together for the construction and implementation of a nuclear reactor devoted to research works in physics, chemistry and biology. The Laue-Langevin Institute project was born with the mission of supplying to researchers an intense neutron beam source for the analysis of condensed matter. Great Britain rapidly joined the project, progressively followed by other European countries and making up the Laue-Langevin Institute a successful example of European cooperation. This success demonstrates that such a gathering of forces and competences allow to carry out ambitious projects with the best neutron source in the world. This book tells us the genesis of this project and shows how a suitable organization has permitted to optimize the reactor use. It describes also the portrait of three personalities that have played a key role in this success: J. Horowitz, H. Maier-Leibnitz and L. Neel. (J.S.)

Results from neutron imaging of ICF experiments at NIF

Science.gov (United States)

Merrill, F. E.; Danly, C. R.; Fittinghoff, D. N.; Grim, G. P.; Guler, N.; Volegov, P. L.; Wilde, C. H.

2016-03-01

In 2011 a neutron imaging diagnostic was commissioned at the National Ignition Facility (NIF). This new system has been used to collect neutron images to measure the size and shape of the burning DT plasma and the surrounding fuel assembly. The imaging technique uses 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 collects 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 one image measures the distribution of the 14 MeV neutrons, and the other image measures the distribution 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. Images have been collected for the majority of the experiments performed as part of the ignition campaign. Results from this data have been used to estimate a burn-averaged fuel assembly as well as providing performance metrics to gauge progress towards ignition. This data set and our interpretation are presented.

D-T neutron generator development for cancer therapy. 1980 annual progress report

International Nuclear Information System (INIS)

Bacon, F.M.; Walko, R.J.; Bickes, R.W. Jr.; Cowgill, D.F.; Riedel, A.A.; O'Hagan, J.B.

1980-05-01

This report summarizes the work completed during the first year of a two-year grant by NCI/HEW to investigate the feasibility of developing a D-T neutron generator for use in cancer therapy. Experiments have continued on the Target Test Facility (TTF) developed during a previous grant to investigate high-temperature metal hydrides for use as target materials. The high voltage reliability of the TTF has been improved so that 200 kV, 200 mA operation is now routine. In recent target tests, the D-D neutron production rate was measured to be > 1 x 10 11 /s, a rate that corresponds to a D-T neutron production rate of > 1 x 10 13 /s - the desired rate for use in cancer therapy. Deuterium concentration depth profiles in the target, measured during intense ion beam bombardment, show that deuterium is depleted near the surface of the target due to impurities implanted by the ion beam. Recent modifications of the duopigatron ion source to reduce secondary electron damage to the electrodes also improved the ion source efficiency by about 40%. An ultra high vacuum version of the TTF is now being constructed to determine if improved vacuum conditions will reduce ion source impurities to a sufficiently low level that the deuterium near the surface of the target is not depleted. Testing will begin in June 1980

1995-1996 progress report; Rapport d`activite 1995-1996

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-09-01

This progress report is mainly devoted to the scientific activity of the LLB or carried out in collaboration with external laboratories. The activity of the LLB is split in several chapters dealing with: magnetism, superconductivity, structures (including lattice dynamics), phase transitions, C{sub 60}, quasi-crystal systems, disordered systems (amorphous, liquids, crystal solid solutions), biology, soft matter (polymers and colloids), physical metallurgy and materials science. Neutron scattering is the main tool used in all these topics but other techniques are also used such as: polarized neutron reflectivity, cold neutrons diffraction, NMR, synchrotron radiation etc. (J.S.)

The pdk-100 enhances interpretation capabilities for pulsed neutron capture logs

International Nuclear Information System (INIS)

Randall, R.R.; Oliver, D.W.; Ferti, W.H.

1986-01-01

The PDK-100 is a new pulsed neutron logging system designed to measure Sigma (Σ), the macroscopic thermal neutron capture cross section. In addition to determining Σ, the system provides logging curves which are a measure of formation porosity and which furnish information concerning borehole conditions. This paper reviews the principles of operation of the PDK-100, and presents examples which illustrate the utility of the logging system. In addition, the progress of investigations into new parameters which can be derived with pulsed neutron logging data will be reported

Proceedings of the first international symposium on neutron capture therapy

Energy Technology Data Exchange (ETDEWEB)

Fairchild, R.G.; Brownell, G.L. (eds.)

1982-01-01

This meeting was arranged jointly by MIT and BNL in order to illuminate progress in the synthesis and targeting of boron compounds and to evaluate and document progress in radiobiological and dosimetric aspects of neutron capture therapy. It is hoped that this meeting will facilitate transfer of information between groups working in these fields, and encourage synergistic collaboration.

Proceedings of the first international symposium on neutron capture therapy

International Nuclear Information System (INIS)

Fairchild, R.G.; Brownell, G.L.

1982-01-01

This meeting was arranged jointly by MIT and BNL in order to illuminate progress in the synthesis and targeting of boron compounds and to evaluate and document progress in radiobiological and dosimetric aspects of neutron capture therapy. It is hoped that this meeting will facilitate transfer of information between groups working in these fields, and encourage synergistic collaboration

Neutron cross section standards and instrumentation: Annual report

International Nuclear Information System (INIS)

1987-01-01

This annual report from the National Bureau of Standards contains a summary of the results of the Neutron Cross Section Standards and Instrumentation Program. The technical measurements for the past year are given along with the proposed program and budget needs for the next three years. The neutron standards measurements have concentrated on the most important 235 U(n,f) cross section in the thermal to 20 MeV energy range along with the development of neutron detectors required for these measurements. The NBS measurements have made a significant contribution to the improvement in the understanding of this reaction. Measurements were performed with numerous neutron detectors at overlapping energies and at different neutron sources in order to reduce the systematic errors to achieve the required accuracy in this important neutron standard. Significant progress was also made in the development of a detector to utilize the 3 He(n,p) reaction as a standard in the eV to MeV energy region. Improvements in data acquisition systems as well as additional studies of advanced neutron sources were accomplished. Contacts with private industry were maintained and coordination of the neutron standards evaluation was continued. The report also includes biographical listings of the research staff along with copies of a few of our recent publications. 13 figs., 1 tab

MODEL ATMOSPHERES FOR X-RAY BURSTING NEUTRON STARS

International Nuclear Information System (INIS)

Medin, Zach; Fontes, Christopher J.; Fryer, Chris L.; Hungerford, Aimee L.; Steinkirch, Marina von; Calder, Alan C.

2016-01-01

The hydrogen and helium accreted by X-ray bursting neutron stars is periodically consumed in runaway thermonuclear reactions that cause the entire surface to glow brightly in X-rays for a few seconds. With models of the emission, the mass and radius of the neutron star can be inferred from the observations. By simultaneously probing neutron star masses and radii, X-ray bursts (XRBs) are one of the strongest diagnostics of the nature of matter at extremely high densities. Accurate determinations of these parameters are difficult, however, due to the highly non-ideal nature of the atmospheres where XRBs occur. Observations from X-ray telescopes such as RXTE and NuStar can potentially place strong constraints on nuclear matter once uncertainties in atmosphere models have been reduced. Here we discuss current progress on modeling atmospheres of X-ray bursting neutron stars and some of the challenges still to be overcome.

MODEL ATMOSPHERES FOR X-RAY BURSTING NEUTRON STARS

Energy Technology Data Exchange (ETDEWEB)

Medin, Zach; Fontes, Christopher J.; Fryer, Chris L.; Hungerford, Aimee L. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Steinkirch, Marina von; Calder, Alan C. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States)

2016-12-01

The hydrogen and helium accreted by X-ray bursting neutron stars is periodically consumed in runaway thermonuclear reactions that cause the entire surface to glow brightly in X-rays for a few seconds. With models of the emission, the mass and radius of the neutron star can be inferred from the observations. By simultaneously probing neutron star masses and radii, X-ray bursts (XRBs) are one of the strongest diagnostics of the nature of matter at extremely high densities. Accurate determinations of these parameters are difficult, however, due to the highly non-ideal nature of the atmospheres where XRBs occur. Observations from X-ray telescopes such as RXTE and NuStar can potentially place strong constraints on nuclear matter once uncertainties in atmosphere models have been reduced. Here we discuss current progress on modeling atmospheres of X-ray bursting neutron stars and some of the challenges still to be overcome.

Recent progress in fast neutron activation cross section data

International Nuclear Information System (INIS)

Michaelis, W.

A brief review is given of some significant investigations performed during the past few years in the area of fast neutron activation cross sections that may be relevant for the use of nuclear techniques in the exploration of mineral resources, in process and quality control in industry as well as for general analytical purposes. Differential capture cross sections are considered for the natural elements or isotopes of Fe, Cu, Se, Y, Nb, Cd, In, Gd, W, Os and Au. Some of the data are compared with statistical model calculations. Experimental and evaluated average cross sections for capture and threshold reactions in the spontaneous fission neutron field of 252 Cf are reviewed taking into account the elements or isotopes of Mg, Al, Si, S, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Sr, Zr, Nb, Cd, In, Ba, Ta and Au. A summary of recent studies of differential cross sections for threshold reactions comprises data on Al, Si, S, Ti, Fe, Co, Ni, Cu, Zn, Zr, Nb, Ta, W and Au. Besides experimental investigations, evaluations and theoretical model calculations are considered. Cross sections at 14 MeV and in the region around this energy are reviewed for Na, Mg, Al, Cl, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Br, Sr, Zr, Nb, In, Er, Yb, Ta, W, Os, Ir, Au and Pb. Particular emphasis is laid on (n,p), (n,2n) and (n,α) reactions. (n,n') reactions are allowed for if the half-life of the metastable state excited permits elemental analyses by common experimental techniques. (orig.)

Three new nondestructive evaluation tools based on high flux neutron sources

International Nuclear Information System (INIS)

Hubbard, C.R.; Raine, D.; Peascoe, R.; Wright, M.

1997-01-01

Nondestructive evaluation methods and systems based on specific attributes of neutron interactions with materials are being developed. The special attributes of neutrons are low attenuation in most engineering materials, strong interaction with low Z elements, and epithermal neutron absorption resonances. The three methods under development at ORNL include neutron based tomography and radiography; through thickness, nondestructive texture mapping; and internal, noninvasive temperature measurement. All three techniques require high flux sources such as the High Flux Isotope Reactor, a steady state source, or the Oak Ridge Electron Linear Accelerator, a pulsed neutron source. Neutrons are quite penetrating in most engineering materials and thus can be useful to detect internal flaws and features. Hydrogen atoms, such as in a hydrocarbon fuel, lubricant, or a metal hydride, are relatively opaque to neutron transmission and thus neutron based tomography/radiography is ideal to image their presence. Texture, the nonrandom orientation of crystalline grains within materials, can be mapped nondestructively using neutron diffraction methods. Epithermal neutron resonance absorption is being studied as a noncontacting temperature sensor. This paper highlights the underlying physics of the methods, progress in development, and the potential benefits for science and industry of the three facilities

Toward whole-core neutron transport without spatial homogenization

International Nuclear Information System (INIS)

Lewis, E. E.

2009-01-01

Full text of publication follows: A long-term goal of computational reactor physics is the deterministic analysis of power reactor core neutronics without incurring significant discretization errors in the energy, spatial or angular variables. In principle, given large enough parallel configurations with unlimited CPU time and memory, this goal could be achieved using existing three-dimensional neutron transport codes. In practice, however, solving the Boltzmann equation for neutrons over the six-dimensional phase space is made intractable by the nature of neutron cross-sections and the complexity and size of power reactor cores. Tens of thousands of energy groups would be required for faithful cross section representation. Likewise, the numerous material interfaces present in power reactor lattices require exceedingly fine spatial mesh structures; these ubiquitous interfaces preclude effective implementation of adaptive grid, mesh-less methods and related techniques that have been applied so successfully in other areas of engineering science. These challenges notwithstanding, substantial progress continues in the pursuit for more robust deterministic methods for whole-core neutronics analysis. This paper examines the progress over roughly the last decade, emphasizing the space-angle variables and the quest to eliminate errors attributable to spatial homogenization. As prolog we briefly assess 1990's methods used in light water reactor analysis and review the lessons learned from the C5G7 benchmark exercises which were originated in 1999 to appraise the ability of transport codes to perform core calculations without homogenization. We proceed by examining progress over the last decade much of which falls into three areas. These may be broadly characterized as reduced homogenization, dynamic homogenization and planar-axial synthesis. In the first, homogenization in three-dimensional calculations is reduced from the fuel assembly to the pin-cell level. In the second

Neutron-Induced Charged Particle Studies at LANSCE

Science.gov (United States)

Lee, Hye Young; Haight, Robert C.

2014-09-01

Direct measurements on neutron-induced charged particle reactions are of interest for nuclear astrophysics and applied nuclear energy. LANSCE (Los Alamos Neutron Science Center) produces neutrons in energy of thermal to several hundreds MeV. There has been an effort at LANSCE to upgrade neutron-induced charged particle detection technique, which follows on (n,z) measurements made previously here and will have improved capabilities including larger solid angles, higher efficiency, and better signal to background ratios. For studying cross sections of low-energy neutron induced alpha reactions, Frisch-gridded ionization chamber is designed with segmented anodes for improving signal-to-noise ratio near reaction thresholds. Since double-differential cross sections on (n,p) and (n,a) reactions up to tens of MeV provide important information on deducing nuclear level density, the ionization chamber will be coupled with silicon strip detectors (DSSD) in order to stop energetic charged particles. In this paper, we will present the status of this development including the progress on detector design, calibrations and Monte Carlo simulations. This work is funded by the US Department of Energy - Los Alamos National Security, LLC under Contract DE-AC52-06NA25396.

Nuclear structure studies via neutron interactions. Progress report, 1 July 1994--30 June 1995

International Nuclear Information System (INIS)

Carlton, R.F.

1995-01-01

Neutron total cross section measurements of 122 Sn has been analyzed over the energy range 0.013 to 0.310 MeV. The R - matrix analysis has resulted in resonance and average parameters which provide for a complete representation of the neutron entrance the s 1/2 , p 1/2 , and p 3/2 contributions. The s - and p - neutron strength functions have been determined to be 0.123 ± 0.023 and 2.0 ± 0.200, respectively (in units of 10 -4 ). Limits are placed on level spacings and strength functions for the individual partial wave components. The s - wave potential scattering radius has been determined to be 6.3 ± 0.1 fm. Average scattering functions, deduced from the average parameters, have been used to determine the real well depth of an optical model potential which reproduces these functions. We find, as have others, that the real well depth is parity dependent. Two computer codes were developed: (1) a minimization program for finding parameters of a dispersive optical model which reproduce the high resolution data of the ORELA facility, and (2) an X-windows graphical user interface has been developed to permit interactive resonance analysis of the neutron total cross section data using analysis-and-minimization codes developed previously. These will contribute to the more routine analysis of ORELA data

Neutron capture therapy (NCT) and in-hospital neutron irradiator (IHNI) a new technology on binary targeting radiation therapy of cancer

International Nuclear Information System (INIS)

Zhou Yongmao

2009-01-01

BNCT is finally becoming 'a new option against cancer'. The difficulties for its development progress of that firstly is to improve the performance of boron compounds,secondly, it is the requirements of quantification and accuracy upon radiation dosimetry evaluation in clinical trials. Furthermore, that is long anticipation on hospital base neutron sources. It includes dedicated new NCT reactor, accelerator based neutron sources, and isotope source facilities. In addition to reactors, so far, the technology of other types of sources for clinical trials is not yet completely proven. The In-Hospital Neutron Irradiator specially designed for NCT, based on the MNSR successfully developed by China, can be installed inside or near the hospital and operated directly by doctors. The Irradiator has two neutron beams for respective treatment of the shallow and deep tumors. It is expected to initiate operation in the end of this year. It would provide a safe, low cost, and effective treatment tool for the NCT routine application in near future. (authors)

Progress report, October 1 to December 31, 1959. Physics Division

International Nuclear Information System (INIS)

1959-01-01

This is a progress report of the Physics Division at Chalk River Nuclear Laboratories from October 1, to December 31, 1959. It describes the research in nuclear physics, general physics, theoretical physics and electronics. The research areas covered in this report include nuclear structure, the tandem accelerator, particle detector development, developments in electronics, neutron decay, beta ray spectrometer, fission studies, electronics development and neutron transport theory.

Symmetry problems in particle physics: Progress report

International Nuclear Information System (INIS)

Kabir, P.K.; Fishbane, P.F.

1988-01-01

Progress is reported in the areas of family symmetry and the fermion mass matrix, consequences of heavy isosinglet fermions, and dynamics of confinement. Theorems were discovered relating the polarization of the transmitted neutrons after passage through a polarized medium to the initial polarization

Neutron--neutron logging

International Nuclear Information System (INIS)

Allen, L.S.

1977-01-01

A borehole logging tool includes a steady-state source of fast neutrons, two epithermal neutron detectors, and two thermal neutron detectors. A count rate meter is connected to each neutron detector. A first ratio detector provides an indication of the porosity of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters connected to the two epithermal neutron detectors. A second ratio detector provides an indication of both porosity and macroscopic absorption cross section of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters connected to the two thermal neutron detectors. By comparing the signals of the two ratio detectors, oil bearing zones and salt water bearing zones within the formation being logged can be distinguished and the amount of oil saturation can be determined. 6 claims, 2 figures

Neutron-induced mutation experiments. Progress report, March 1, 1975--February 29, 1976

International Nuclear Information System (INIS)

Abrahamson, S.

1975-11-01

The relative mutagenic effectiveness of neutrons of different energies were compared with x radiation in mice and Drosophila oogonia employing X-linked recessive lethal and specific locus mutation tests. The energies and doses used were 0.68 MeV, 2 MeV, and 6 MeV (250 and 500 0 R), and 15 MeV (250, 500, and 1000 0 R). The data thus far collected from the recessive lethal test indicate that 0.68 MeV neutrons have the highest RBE among the energies tested, followed by 6 and 2 MeV. The specific locus mutation data also indicate the highest RBE for 0.68 MeV, followed respectively by 2 and 6 MeV. The 15 MeV data is as of now incompletely analyzed, as are some dose points of 2 and 6 MeV

Triton beta decay

International Nuclear Information System (INIS)

Saito, T.Y.; Wu, Y.; Ishikawa, S.; Sasakawa, T.

1990-01-01

Triton β-decay has been calculated using wave functions for 3 He and 3 H obtained from (Coulomb-modified) Faddeev equations for various interactions. We get a value for the Gamow-Teller matrix element of √3 (0.962±0.002) without regards to two- or three-nucleon inteactions. This value agrees with the experimental value. (orig.)

KURRI progress report 2003. April 2003-March 2004

International Nuclear Information System (INIS)

2004-01-01

The Kyoto University Reactor (KUR) and the critical assembly KUCA were operated for 1,341 and 813 hours in the fiscal year 2003. The 5,246 man-day researchers visited the KURRI to make experimental studies. The scientific activities in the fiscal year of 2003 are summarized in this progress report. The total 157 research issues are categorized to the 10 topics as follows; (1) Slow Neutron Physics and Neutron Scattering includes 16 issues as general researches. (2) Nuclear Physics and Nuclear Data includes the 6 issues for the project research on advanced uses of RI beam produced by KUR-ISOL and the 4 issues as general researches. (3) Reactor Physics and Reactor Engineering includes the 4 issues as general researches. (4) Material Science and Radiation Effects includes the 22 issues for the project research on condensed matter with short-lived nuclei and on the initial damage processed in high energy particle irradiated materials and the 23 issues as general researches. (5) Geochemistry and Environmental Science includes the 18 issues as general researches. (6) Life Science and Medical Science includes the 5 issues for the project research on the effects of neutron, gamma-ray and UV irradiation on proteins and the 14 issues as general researches. (7) Neutron Capture Therapy includes the 18 issues as general researches. (8) Neutron Radiography and Radiation Application includes the 10 issues for the project research on the development of neutron optical devices and its application to new type neutron spectrometer and imaging and the 4 issues as general researches. (9) TRU and Nuclear Chemistry includes the 9 issues for the project research on nuclear physical and chemical characteristics of actinide and fission product nuclides and the 1 issue as general researches. (10) Health Physics and Waste Management includes the 3 issues as general researches. This progress report also includes organization, research divisions and laboratories, operation and development of

The LANL/LLNL Program to Measure Prompt Fission Neutron Spectra at LANSCE

Science.gov (United States)

Haight, Robert; Wu, Ching Yen; Lee, Hye Young; Taddeucci, Terry; Mosby, Shea; O'Donnell, John; Fotiades, Nikolaos; Devlin, Mattew; Ullmann, John; Nelson, Ronald; Wender, Stephen; White, Morgan; Solomon, Clell; Neudecker, Denise; Talou, Patrick; Rising, Michael; Bucher, Brian; Buckner, Matthew; Henderson, Roger

2015-10-01

Accurate data on the spectrum of neutrons emitted in neutron-induced fission are needed for applications and for a better understanding of the fission process. At LANSCE we have made important progress in understanding systematic uncertainties and in obtaining data for 235U on the low-energy part of the prompt fission neutron spectra (PFNS), a particularly difficult region because down-scattered neutrons go in this direction. We use a double time-of-flight technique to determine energies of incoming and outgoing neutrons. With data acquisition via waveform digitizers, accidental coincidences between fission chamber and neutron detector are measured to high statistical accuracy and then subtracted from measured events. Monte Carlo simulations with high performance computers have proven to be essential in the design to minimize neutron scattering and in calculating detector response. Results from one of three approaches to analyzing the data will be presented. This work is funded by the US Department of Energy, National Nuclear Security Administration and Office of Nuclear Physics.

Neutron scatter studies of chromatin structures related to functions

International Nuclear Information System (INIS)

Bradbury, E.M.

1992-01-01

Despite of setbacks in the lack of neutrons for the proposed We have made considerable progress in chromatin reconstitution with the VLR histone H1/H5 and in understanding the dynamics of nucleosomes. A ferromagnetic fluid was developed to align biological molecules for structural studies using small-angle-neutron-scattering. We have also identified and characterized an intrinsically bent DNA region flanking the RNA polymerase I binding site of the ribosomal RNA gene in Physarum Polycephalum. Finally projects in progress are in the areas of studying the interatctions of histone H4 amino-terminus peptide 1-23 and acetylated 1-23 peptide with DNA using thermal denaturation; study of GGAAT repeats found in human centromeres using high resolution Nuclear magnetic Resonance and nuclease sentivity assay; and the role of histones and other sperm specific proteins with sperm chromatin

Development and application of the electrochemical etching technique. Annual progress report

Energy Technology Data Exchange (ETDEWEB)

1980-08-01

This annual progress report documents further advances in the development and application of electrochemical etching of polycarbonate foils (ECEPF) for fast, intermediate, and thermal neutron dosimetry as well as alpha particle dosimetry. The fast (> 1.1 MeV) and thermal neutron dosimetry techniques were applied to a thorough investigation of the neutron contamination inherent in and about the primary x-ray beam of several medical therapy electron accelerators. Because of the small size of ECEPF dosimeters in comparison to other neutron meters, they have an unusually low perturbation of the radiation field under measurement. Due to this small size and the increased sensitivity of the ECEPF dosimeter over current techniques of measuring neutrons in a high photon field, the fast neutron contamination in the primary x-ray beam of all the investigated accelerators was measured with precision and found to be greater than that suggested by the other, more common, neutron dosimetry methods.

Development and application of the electrochemical etching technique. Annual progress report

International Nuclear Information System (INIS)

1980-08-01

This annual progress report documents further advances in the development and application of electrochemical etching of polycarbonate foils (ECEPF) for fast, intermediate, and thermal neutron dosimetry as well as alpha particle dosimetry. The fast (> 1.1 MeV) and thermal neutron dosimetry techniques were applied to a thorough investigation of the neutron contamination inherent in and about the primary x-ray beam of several medical therapy electron accelerators. Because of the small size of ECEPF dosimeters in comparison to other neutron meters, they have an unusually low perturbation of the radiation field under measurement. Due to this small size and the increased sensitivity of the ECEPF dosimeter over current techniques of measuring neutrons in a high photon field, the fast neutron contamination in the primary x-ray beam of all the investigated accelerators was measured with precision and found to be greater than that suggested by the other, more common, neutron dosimetry methods

Ultra-low-temperature neutron diffraction. Final report, July 1, 1983-June 30, 1985. Final report

International Nuclear Information System (INIS)

Halperin, W.P.; Ketterson, J.B.

1985-07-01

An ultra-low-temperature neutron diffraction facility has been constructed at Argonne National Laboratory. The initial and primary purpose of this facility is to study nuclear magnetic ordering phenomenon. Magnetic structure information is commonly recognized as being fundamental to the progress in theoretical and experimental efforts in the field of magnetism. We have initiated study of the nuclear spin in solid 3 He and in metals. In 3 He the nuclear spins order at 1.1 mK. Structure information for neutron diffraction would contribute significantly to this problem of nuclear magnetism. Despite substantial experimental difficulties, careful evaluation suggests that examination of the nuclear structure in this unique quantum crystal is indeed feasible by neutron diffraction. Substantial progress has been made in growing single crystals of 3 He and establishing its temperature in the presence of a neutron flux. We have also initiated investigation of nuclear ordering in copper and PrCu 6

FMIT Test assemblies. Progress report

International Nuclear Information System (INIS)

Nygren, R.E.; Opperman, E.K.

1978-08-01

This progress report is a reference document for a number of inter-related tasks supporting the Fusion Materials Irradiation Test (FMIT) Facility being developed by the Hanford Engineering Development Laboratory. The report describes the basic configuration of test assemblies and supporting rationale based on the neutron flux distribution. Perturbed and unperturbed flux profiles are discussed as well as heating rates and cooling requirements

A retrospective analysis of the results of p(65) + Be neutron therapy for the treatment of prostate adenocarcinoma at the cyclotron of Louvain-la-Neuve. Part I: survival and progression-free survival

International Nuclear Information System (INIS)

Scalliet, P.G.M.; Remouchamps, V.; Wambersie, A.; Richard, F.; Lhoas, F.; Van Glabbeke, M.; Curran, D.; Van Cangh, P.; Ledent, T.

2001-01-01

Purpose. -To retrospectively evaluate survival, progression free survival (PFS) and biological response in a series of patients irradiated with mixed neutron/photon beams for locally advanced prostate cancer in our institution. Patients and methods. - Three hundred and eight patients were treated between January 1990 and December 1996. Fifty-five of these were recruited for pT3 or pN1 tumors after radical prostatectomy. Neo-adjuvant androgen deprivation was given in 106 patients. The treatment protocol consisted of a mixed photon/neutron irradiation in a two-to-three proportion, up to a total equivalent dose of 66 Gy (assuming a clinical RBE value of 2.8). Pre- and post-treatment PSA determinations were available in practically all cases. Study endpoints were overall survival (OAS) and progression-free survival (PFS). The Cox proportional hazard regression model was used to investigate the prognostic value of baseline characteristics on survival and progression-free survival were a progression was defined as local, regional, metastatic or biological progression. Mean age was 69 years (49-86); mean pretreatment PSA was 15 (0.5-330) in all patients and 14 (0.5-160) in those receiving neo-adjuvant hormonotherapy; seven patients only had an initial PSA S 4 ng/mL; 15% were T1, 46% were T2, 28% were T3 or pT3 and 4% were T4 (7% unspecified); WHO grade of differentiation was I in 38%, II in 38% and III in 14% (5% unspecified). Results. -The median follow-up was 2.8 years (0-7.8). Five year overall survival (OAS) was 79% (95% CI: 71-87%) and 5-year progression-free survival (PFS) was 64% (95% Cl: 54-74%) for the entire series. PFS in patients with an initial PSA >- 20 ng/mL was the same. PFS could be predicted by two optimal Cox regression models, one including histological grade (p = 0.003) and initial PSA (p = 0.0009) as cofactors, the other including histological grade (p = 0.003) and T stage (p = 0.02). The main prognostic factors for overall survival were PSA and age

Direct fast neutron detection: A status report

International Nuclear Information System (INIS)

Peurrung, A.J.; Hansen, R.R.; Craig, R.A.; Hensley, W.K.; Hubbard, C.W.; Keller, P.E.; Reeder, P.L.; Sunberg, D.S.

1997-12-01

This report describes the status of efforts to develop direct fast-neutron detection via proton recoil within plastic scintillator. Since recording proton recoil events is of little practical use without a means to discriminate effectively against gamma-ray interactions, the present effort is concentrated on demonstrating a method that distinguishes between pulse types. The proposed method exploits the different pulse shapes that are to be expected primarily on the basis of the slower speed of the recoiling fission neutrons. Should this effort ultimately prove successful, the resulting novel technology will have the potential to significantly lower cost and increase capability for a number of critical neutron-detection applications. Considerable progress has been made toward a clear and compelling demonstration of this new technique. An exhaustive theoretical and numerical investigation of the method has been completed. The authors have been able to better understand the laboratory results and estimate the performance that could ultimately be achieved using the proposed technique. They have assessed the performance of a number of different algorithms for discriminating between neutron and gamma ray events. The results of this assessment will be critical when the construction of low-cost, field-portable neutron detectors becomes necessary. Finally, a laboratory effort to realize effective discrimination is well underway and has resulted in partial success

Nuclear structure/nuclei far from stability

International Nuclear Information System (INIS)

Casten, R.F.; Garrett, J.D.; Moller, P.; Bauer, W.W.; Brenner, D.S.; Butler, G.W.; Crawford, J.E.; Davids, C.N.; Dyer, P.L.; Gregorich, K.; Hagbert, E.G.; Hamilton, W.D.; Harar, S.; Haustein, P.E.; Hayes, A.C.; Hoffman, D.C.; Hsu, H.H.; Madland, D.G.; Myers, W.D.; Penttila, H.T.; Ragnarsson, I.; Reeder, P.L.; Robertson, G.H.; Rowley, N.; Schreiber, F.; Seifert, H.L.; Sherrill, B.M.; Siciliano, E.R.; Sprouse, G.D.; Stephens, F.S.; Subotic, K.; Talbert, W.; Toth, K.S.; Tu, X.L.; Vieira, D.J.; Villari, A.C.C.; Walters, W.B.; Wildenthal, B.H.; Wilhelmy, J.B.; Winger, J.A.; Wohn, F.K.; Wouters, J.M.; Zhou, X.G.; Zhou, Z.Y.

1990-01-01

This report outlines some of the nuclear structure topics discussed at the Los Alamos Workshop on the Science of Intense Radioactive Ion Beams (RIB). In it we also tried to convey some of the excitement of the participants for utilizing RIBs in their future research. The introduction of radioactive beams promises to be a major milestone for nuclear structure perhaps even more important than the last such advance in beams based on the advent of heavy-ion accelerators in the 1960's. RIBs not only will allow a vast number of new nuclei to be studies at the extremes of isospin, but the variety of combinations of exotic proton and neutron configurations should lead to entirely new phenomena. A number of these intriguing new studies and the profound consequences that they promise for understanding the structure of the atomic nucleus, nature's only many-body, strongly-inteacting quantum system, are discussed in the preceeding sections. However, as with any scientific frontier, the most interesting phenomena probably will be those that are not anticipated--they will be truly new

Recent progress of hydrogen isotope behavior studies for neutron or heavy ion damaged W

International Nuclear Information System (INIS)

Oya, Yasuhisa; Hatano, Yuji; Shimada, Masashi; Buchenauer, Dean; Kolasinski, Robert; Merrill, Brad; Kondo, Sosuke; Hinoki, Tatsuya; Alimov, Vladimir Kh.

2016-01-01

Highlights: • This paper reviews recent results pertaining to hydrogen isotope behavior in neutron and heavy ion damaged W. • Accumulation of damage in W creates stable trapping sites for hydrogen isotopes, thereby changing the observed desorption behavior. • The distribution of defects throughout the sample also changes the shape of TDS spectrum. • Experimental results show that production of Re by nuclear reaction of W with neutrons reduces the density of trapping sites, though no remarkable retention enhancement is observed. - Abstract: This paper reviews recent results pertaining to hydrogen isotope behavior in neutron and heavy ion damaged W. Accumulation of damage in W creates stable trapping sites for hydrogen isotopes, thereby changing the observed desorption behavior. In particular, the desorption temperature shifts higher as the defect concentration increases. In addition, the distribution of defects throughout the sample also changes the shape of TDS spectrum. Even if low energy traps were distributed in the bulk region, the D diffusion toward the surface requires additional time for trapping/detrapping during surface-to-bulk transport, contributing to a shift of desorption peaks toward higher temperatures. It can be said that both of distribution of damage (e.g. hydrogen isotope trapping sites) and their stabilities would have a large impact on desorption. In addition, transmutation effects should be also considered for an actual fusion environment. Experimental results show that production of Re by nuclear reaction of W with neutrons reduces the density of trapping sites, though no remarkable retention enhancement is observed.

Recent progress of hydrogen isotope behavior studies for neutron or heavy ion damaged W

Energy Technology Data Exchange (ETDEWEB)

Oya, Yasuhisa, E-mail: syoya@ipc.shizuoka.ac.jp [Shizuoka University, 836 Ohya, Suruga-ku Shizuoka 422-8529 (Japan); Hatano, Yuji [University of Toyama, 3190 Gofuku, Toyama 939-8555 (Japan); Shimada, Masashi [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Buchenauer, Dean; Kolasinski, Robert [Sandia National Laboratories, Livermore, CA 94551 (United States); Merrill, Brad [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Kondo, Sosuke; Hinoki, Tatsuya [Kyoto University, Gokasho, Uji 611-0011 (Japan); Alimov, Vladimir Kh. [University of Toyama, 3190 Gofuku, Toyama 939-8555 (Japan)

2016-12-15

Highlights: • This paper reviews recent results pertaining to hydrogen isotope behavior in neutron and heavy ion damaged W. • Accumulation of damage in W creates stable trapping sites for hydrogen isotopes, thereby changing the observed desorption behavior. • The distribution of defects throughout the sample also changes the shape of TDS spectrum. • Experimental results show that production of Re by nuclear reaction of W with neutrons reduces the density of trapping sites, though no remarkable retention enhancement is observed. - Abstract: This paper reviews recent results pertaining to hydrogen isotope behavior in neutron and heavy ion damaged W. Accumulation of damage in W creates stable trapping sites for hydrogen isotopes, thereby changing the observed desorption behavior. In particular, the desorption temperature shifts higher as the defect concentration increases. In addition, the distribution of defects throughout the sample also changes the shape of TDS spectrum. Even if low energy traps were distributed in the bulk region, the D diffusion toward the surface requires additional time for trapping/detrapping during surface-to-bulk transport, contributing to a shift of desorption peaks toward higher temperatures. It can be said that both of distribution of damage (e.g. hydrogen isotope trapping sites) and their stabilities would have a large impact on desorption. In addition, transmutation effects should be also considered for an actual fusion environment. Experimental results show that production of Re by nuclear reaction of W with neutrons reduces the density of trapping sites, though no remarkable retention enhancement is observed.

Neutron radiography with ultracold neutrons

International Nuclear Information System (INIS)

Bates, J.C.

1981-01-01

The neutron transmission factor of very thin films may be low if the neutron energy is comparable to the pseudo-potential of the film material. Surprisingly, perhaps, it is relatively easy to obtain neutrons with such low energies in sufficient numbers to produce neutron radiographs. (orig.)

Inelastic neutron scattering from synthetic and biological polymers

International Nuclear Information System (INIS)

White, J.W.

1976-01-01

Neutron elastic and inelastic scattering measurements have provided many unique insights into structure, and by reviewing progress on synthetics, important differences likely to arise in biological systems are identified and a direction for studies of the latter is suggested. By neutron inelastic scattering it is possible to measure the frequency of thermally excited interatomic and intermolecular vibrations in crystals. With perfect organic and inorganic crystals the technique is now classical and has given great insight into the crystal forces responsible for the observed structures as well as the phase transitions they undergo. The study of polymer crystals immediately presents two problems of disorder: (1) Macroscopic disorder arises because the sample is a mixture of amorphous and crystalline fractions, and it may be acute enough to inhibit growth of a single crystal large enough for neutron studies. (2) Microscopic disorder in the packing of polymer chains in the ''crystalline'' regions is indicated by broadening of Bragg peaks. Both types of disorder problem arise in biological systems. The methods by which they were partially overcome to allow neutron measurements with synthetic polymers are described but first a classical example of the determination of interatomic forces by inelastic neutron scattering is given

KURRI progress report 2006. April 2006 - March 2007

International Nuclear Information System (INIS)

2007-01-01

The fiscal year 2006 was the first year of outage period of the Kyoto University research Reactor (KUR) because of fuel conversion procedure from the highly enriched uranium (HEU) fuel of 93% to the low enriched uranium (LEU) of 20%. Meanwhile, the Kyoto University Critical Assembly (KUCA) have been operated for 767 hours. Kyoto University Research Reactor Institute (KURRI) accepted 3,120 man-day researchers including students in total for their experiments in accordance with the joint use programs among Japanese universities and public research organizations, and for scientific meetings held at KURRI. In addition, 104 and 139 man-day researchers have been sent to the research reactor HANARO in Korea Atomic Energy Research Institute (KAERI) and the research reactor JRR-4 in Japan Atomic Energy Agency (JAEA), respectively, in the framework of project research in the joint use program at KURRI. The results of these activities are reported in this progress report. The total 98 research issues are categorized to the 3 types of Project Research, Collaboration Research and Original Research. Project Research includes the 9 studies as follows; (1) Production of radioactive nuclei and their application to material science. (2) Fundamental study on radiation protection of fixed-field alternating-gradient accelerator. (3) Study on the effects of structure and function of proteins by irradiation and repair mechanism. (4) Study of materials irradiation effects and improvement of irradiation fields. (5) Study on neutron reaction cross sections using various neutron sources. (6) Nuclear physical and chemical characteristics of actinide and fission product nuclides. (7) Clinical study of boron neutron capture therapy as JRR-4 project. (8) Neutron activation analysis experiments using HANARO as HANARO project. (9) Development and application of new technology on neutron imaging as HANARO project. Collaboration Research includes the 8 topics as follows; (1) Slow Neutron Physics and

Neutron powder diffraction under high pressure at J-PARC

International Nuclear Information System (INIS)

Utsumi, Wataru; Kagi, Hiroyuki; Komatsu, Kazuki; Arima, Hiroshi; Nagai, Takaya; Okuchi, Takuo; Kamiyama, Takashi; Uwatoko, Yoshiya; Matsubayashi, Kazuyuki; Yagi, Takehiko

2009-01-01

It is expected that high-pressure material science and the investigation of the Earth's interior will progress greatly using the high-flux pulse neutrons of J-PARC. In this article, we introduce our plans for in situ neutron powder diffraction experiments under high pressure at J-PARC. The use of three different types of high-pressure devices is planned; a Paris-Edinburgh cell, a new opposed-anvil cell with a nano-polycrystalline diamond, and a cubic anvil high-pressure apparatus. These devices will be brought to the neutron powder diffraction beamlines to conduct a 'day-one' high-pressure experiment. For the next stage of research, we propose construction of a dedicated beamline for high-pressure material science. Its conceptual designs are also introduced here.

About possibilities of obtaining focused beams of thermal neutrons of radionuclide source

International Nuclear Information System (INIS)

Aripov, G.A.; Kurbanov, B.I.; Sulaymanov, N.T.; Ergashev, A.

2004-01-01

Full text: In the last years significant progress is achieved in development of neutron focusing methods (concentrating neutrons in a given direction and a small area). In this, main attention is given to focusing of neutron beams of reactor, particularly cold neutrons and their applications. [1,2]. However, isotope sources also let obtain intensive neutron beams and solve quite important (tasks) problems (e.g. neutron capture therapy for malignant tumors) [3], and an actual problems is focusing of neutrons. We developed a device on the basis of californium source of neutrons, allowing to obtain focused (preliminarily) beam of thermal neutrons with the aid of respective choice of moderators, reflectors and geometry of their disposition. Here, fast neutrons and gamma rays in the beam are minimized. With the aid of the model we developed on the basis of Monte-Carlo method, it is possible to modify aforementioned device and dynamics of output neutrons in wide energy range and analyze ways of optimization of neutron beams of isotope sources with different neutron outputs. Device of preliminary focusing of thermal neutrons can serve as a basis for further focus of neutrons using micro- and nano-capillar systems. It is known that, capillary systems performed with certain technology can form beam of thermal neutrons increasing its density by more than two orders of magnitude and effectively divert beams up to 20 o with length of system 15 cm

About possibilities of obtaining focused beams of thermal neutrons of radionuclide source

International Nuclear Information System (INIS)

Aripov, G.A.; Kurbanov, B.I.; Sulaymanov, N.T.; Ergashev, A.

2004-01-01

In the last years significant progress is achieved in development of neutron focusing methods (concentrating neutrons in a given direction and a small area). In this, main attention is given to focusing of neutron beams of reactor, particularly cold neutrons and their applications. [1,2]. However, isotope sources also let obtain intensive neutron beams and solve quite important (tasks) problems (e.g. neutron capture therapy for malignant tumors) [3], and an actual problems is focusing of neutrons. We developed a device on the basis of californium source of neutrons, allowing to obtain focused (preliminarily) beam of thermal neutrons with the aid of respective choice of moderators, reflectors and geometry of their disposition. Here, fast neutrons and gamma rays in the beam are minimized. With the aid of the model we developed on the basis of Monte-Carlo method, it is possible to modify aforementioned device and dynamics of output neutrons in wide energy range and analyze ways of optimization of neutron beams of isotope sources with different neutron outputs. Device of preliminary focusing of thermal neutrons can serve as a basis for further focus of neutrons using micro- and nano-capillary systems. It is known that, capillary systems performed with certain technology can form beam of thermal neutrons increasing its density by more than two orders of magnitude and effectively divert beams up to 20 o with length of system 15 cm. (author)

Neutron Scattering and the 30 S Ribosomal Subunit of E. Coli

Science.gov (United States)

Moore, P. B.; Engelman, D. M.; Langer, J. A.; Ramakrishnan, V. R.; Schindler, D. G.; Schoenborn, B. P.; Sillers, I. Y.; Yabuki, S.

1982-06-01

This paper reviews the progress made in the study of the internal organization of the 30 S ribosomal subunit of E. coli by neutron scattering since 1975. A map of that particle showing the position of 14 of the subunit's 21 proteins is presented, and the methods currently used for collecting and analyzing such data are discussed. Also discussed is the possibility of extending the interpretation of neutron mapping data beyond the limits practical today.

Neutron Skins and Neutron Stars

OpenAIRE

Piekarewicz, J.

2013-01-01

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 208Pb. In this contribution we examine how the increased accuracy in the determination of neutron skins expected from the commissioning of intense polarized electron be...

Ames collaborative study of cosmic-ray neutrons. II. Low- and mid-latitude flights

International Nuclear Information System (INIS)

Stephens, L.D.; McCaslin, J.B.; Smith, A.R.; Thomas, R.H.; Hewitt, J.E.; Hughes, L.

1978-01-01

The continuing progress of the Ames Collaborative Study of Cosmic Ray Neutrons is described. Data obtained aboard flights from Hawaii at altitudes of 41,000 and 45,000 feet, and in the range of geomagnetic latitude 17 0 N less than or equal to lambda less than or equal to 21 0 N are reported. Preliminary estimates of neutron spectra were made

Absolute measurement of the DT primary neutron yield on the National Ignition Facility

Directory of Open Access Journals (Sweden)

Leeper R.J.

2013-11-01

Full Text Available The measurement of the absolute neutron yield produced in inertial confinement fusion target experiments conducted on the National Ignition Facility (NIF is essential in benchmarking progress towards the goal of achieving ignition on this facility. This paper describes three independent diagnostic techniques that have been developed to make accurate and precise DT neutron yield measurements on the NIF.

The theory of hadronic systems. Annual progress report

International Nuclear Information System (INIS)

Gibbs, W.R.

1993-01-01

This report briefly discusses progress on the following topics: isospin breaking in the pion-nucleon system; direct capture of pions into deeply bound atomic states; knock out of secondary components in the nucleus; study of the radii of neutron distributions in nuclei; the hadronic double scattering operator; transparency in pion production; asymmetry in pion scattering and charge exchange from polarized nuclei; the mechanism of pion absorption in nuclei; the neutron-proton charge-exchange reaction; modification of the fundamental structure of nucleons in nuclei; and antiproton annihilation in nuclei

Progress report, Physics Division, 1 October - 31 December, 1981

International Nuclear Information System (INIS)

1982-03-01

The work of the Physics Division during the quarter is reviewed. Nuclear physics activities included parity violation experiments, mass difference measurements using the ISOL facility, studies of high spin state decays, and scattering length measurements. In accelerator physics, construction of the heavy-ion superconducting cyclotron continued and development of the fast intense neutron source and the high current proton accelerator progressed. Neutron scattering experiments were carried out on a number of solids. Work in applied mathematics and computation is also reviewed

Computational complexity in multidimensional neutron transport theory calculations. Progress report, September 1, 1974--August 31, 1975

International Nuclear Information System (INIS)

Bareiss, E.H.

1975-01-01

The objectives of the research remain the same as outlined in the original proposal. They are in short as follows: Develop mathematically and computationally founded criteria for the design of highly efficient and reliable multi-dimensional neutron transport codes to solve a variety of neutron migration and radiation problems and analyze existing and new methods for performance. (U.S.)

[Absolute fission cross sections in the 14 MeV energy region]. Progress report, July 1982-June 1983

International Nuclear Information System (INIS)

1983-01-01

Progress is reported on the following studies: thermal neutron absorption cross section of sulfur and the 252 Cf nu bar dilemma, the sigma (H)/sigma (Mn) cross section ratio, the sigma (H)/sigma (B) cross section ratio, 14 MeV neutron cross section measurements, beryllium-based pulsed neutron detector, and testing charged particle transport and Monte Carlo codes

Hazards control progress report No. 58, April-September 1979

International Nuclear Information System (INIS)

Griffith, R.V.

1980-01-01

Progress is reported on research in the areas of radiation protection and industrial hygiene. Subject areas include: (1) basic computer programs for counting room automation; (2) a computing portable neutron spectrometer; (3) preliminary measurements of the neutron energy response of CR-39 carbonate plastic; (4) effect of high-expansion foam on self-1 contained breathing apparatuses; (5) permeation of organic solvents through glove samples; (6) determining neutron dose rates and 9-to-3 in. sphere ratios from a moderated 252Cf source in the LLL Calibration Facility; (7) application of the AERIN computer code to two americium inhalation exposures; and (8) air- and soil-sampling program at Site 300's high-explosive test bombers

Neutron-neutron probe for uranium exploration

International Nuclear Information System (INIS)

Smith, R.C.

1979-01-01

A neutron activation probe for assaying the amount of fissionable isotopes in an ore body is described which comprises a casing which is movable through a borehole in the ore body, a neutron source and a number of delayed neutron detectors arranged colinearly in the casing below the neutron source for detecting delayed neutrons

Neutron Energy Spectra from Neutron Induced Fission of 235U at 0.95 MeV and of 238U at 1.35 and 2.02 MeV

Energy Technology Data Exchange (ETDEWEB)

Almen, E; Holmqvist, B; Wiedling, T

1971-09-15

The shapes of fission neutron spectra are of interest for power reactor calculations. Recently it has been suggested that the neutron induced fission spectrum of 235U may be harder than was earlier assumed. For this reason measurements of the neutron spectra of some fissile isotopes are in progress at our laboratory. This report will present results from studies of the energy spectra of the neutrons emitted in the neutron induced fission of 235U and 238U. The measurements were performed at an incident neutron energy of 0.95 MeV for 235U and at energies of 1.35 and 2.02 MeV for 238U using time-of-flight techniques. The time-of-flight spectra were only analysed at energies higher than those of the incident neutrons and up to about 10 MeV. Corrections for neutron attenuation in the uranium samples were calculated using a Monte Carlo program. The corrected fission neutron spectra were fitted to Maxwellian temperature distributions. For 235U a temperature of 1.27 +- 0.01 MeV gives the best fit to the experimental data and for 238U the corresponding values are 1.29 +- 0.03 MeV at 1.35 MeV and 1.29 +- 0.02 MeV at 2.02 MeV

Progress Toward Heavy Ion IFE

International Nuclear Information System (INIS)

Meier, W.R.; Logan, B.G.; Waldron, W.L.; Sabbi, G.L.; Callahan-Miller, D.A.; Peterson, P.F.; Goodin, D.T.

2002-01-01

Successful development of Heavy Ion Fusion (HIF) will require scientific and technology advances in areas of targets, drivers and chambers. Design work on heavy ion targets indicates that high gain (60-130) may be possible with a -3-6 MJ driver depending on the ability to focus the beams to small spot sizes. Significant improvements have been made on key components of heavy ion drivers, including sources, injectors, insulators and ferromagnetic materials for long-pulse induction accelerator cells, solid-state pulsers, and superconducting quadrupole magnets. The leading chamber concept for HIF is the thick-liquid-wall HYLEE-II design, which uses an array of flibe jets to protect chamber structures from x-ray, debris, and neutron damage. Significant progress has been made in demonstrating the ability to create and control the types of flow needed to form the protective liquid blanket. Progress has also been made on neutron shielding for the final focus magnet arrays with predicted lifetimes now exceeding the life of the power plant. Safety analyses have been completed for the HYLEE-II design using state-of-the-art codes. Work also continues on target fabrication and injection for HE. A target injector experiment capable of > 5 Hz operation has been designed and construction will start in 2002. Methods for mass production of hohlraum targets are being evaluated with small-scale experiments and analyses. Progress in these areas will be reviewed

Progress toward heavy-ion IFE

International Nuclear Information System (INIS)

Meier, W.R.; Logan, B.G.; Waldron, W.L.; Sabbi, G.-L.; Callahan, D.A.; Peterson, P.F.; Goodin, D.T.

2002-01-01

Successful development of heavy-ion fusion (HIF) will require scientific and technology advances in areas of targets, drivers and chambers. Design work on heavy-ion targets indicates that high gain (60-130) may be possible with a ∼3-6 MJ driver depending on the ability to focus the beams to small spot sizes. Significant improvements have been made on key components of heavy-ion drivers, including sources, injectors, insulators and ferromagnetic materials for long-pulse induction accelerator cells, solid-state pulsers, and superconducting quadrupole magnets. The leading chamber concept for HIF is the thick-liquid-wall HYLIFE-II design, which uses an array of flibe jets to protect chamber structures from X-ray, debris, and neutron damage. Significant progress has been made in demonstrating the ability to create and control the types of flow needed to form the protective liquid blanket. Progress has also been made on neutron shielding for the final focus magnet arrays with predicted lifetimes now exceeding the life of the power plant. Safety analyses have been completed for the HYLIFE-II design using state-of-the-art codes. Work also continues on target fabrication and injection for HIF. A target injector experiment capable of >5 Hz operation has been designed and construction will start in 2002. Methods for mass-production of hohlraum targets are being evaluated with small-scale experiments and analyses. Progress in these areas will be reviewed

Progress report on reactor physics research program, January 1963 - February 1964

Energy Technology Data Exchange (ETDEWEB)

NONE

1964-02-15

This progress report is a part of the annual report of the department of reactor physics prepared for the Boris Kidric Institute of nuclear sciences. It is a review of research activities in the field of theoretical and experimental reactor physics in the year 1973. A part of this program was included in the NPY Cooperative program in reactor physics. The topics covered by this report are as follows: Calculations of the thermal neutron distribution and reaction rate in a reactor cell and comparison with experiments; buckling measurements; thermalization and slowing down of neutrons; pulsed neutron source techniques; and reactor kinetics.

Progress report on reactor physics research program, January 1963 - February 1964

International Nuclear Information System (INIS)

1964-02-01

This progress report is a part of the annual report of the department of reactor physics prepared for the Boris Kidric Institute of nuclear sciences. It is a review of research activities in the field of theoretical and experimental reactor physics in the year 1973. A part of this program was included in the NPY Cooperative program in reactor physics. The topics covered by this report are as follows: Calculations of the thermal neutron distribution and reaction rate in a reactor cell and comparison with experiments; buckling measurements; thermalization and slowing down of neutrons; pulsed neutron source techniques; and reactor kinetics

Quantitative neutron radiography using neutron absorbing honeycomb

International Nuclear Information System (INIS)

Tamaki, Masayoshi; Oda, Masahiro; Takahashi, Kenji; Ohkubo, Kohei; Tasaka, Kanji; Tsuruno, Akira; Matsubayashi, Masahito.

1993-01-01

This investigation concerns quantitative neutron radiography and computed tomography by using a neutron absorbing honeycomb collimator. By setting the neutron absorbing honeycomb collimator between object and imaging system, neutrons scattered in the object were absorbed by the honeycomb material and eliminated before coming to the imaging system, but the neutrons which were transmitted the object without interaction could reach the imaging system. The image by purely transmitted neutrons gives the quantitative information. Two honeycombs were prepared with coating of boron nitride and gadolinium oxide and evaluated for the quantitative application. The relation between the neutron total cross section and the attenuation coefficient confirmed that they were in a fairly good agreement. Application to quantitative computed tomography was also successfully conducted. The new neutron radiography method using the neutron-absorbing honeycomb collimator for the elimination of the scattered neutrons improved remarkably the quantitativeness of the neutron radiography and computed tomography. (author)

Synthesis and study of neutron-rich nuclides

International Nuclear Information System (INIS)

Luo, Y.X.

1995-01-01

During the past few years our understanding of the decay properties and nuclear structure has been extended in a systematic fashion for the neutron-rich nuclei. This review will discuss the impressive progress in the studies of the exotic decay properties and nuclear structure of n-rich nuclei. Their astrophysical implications will also be outlined. ((orig.))

Neutron dosimetry; Dosimetria de neutrons

Energy Technology Data Exchange (ETDEWEB)

Fratin, Luciano

1993-12-31

A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

Neutron dosimetry; Dosimetria de neutrons

Energy Technology Data Exchange (ETDEWEB)

Fratin, Luciano

1994-12-31

A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

Summary Report from the Consultants' Meeting on International Neutron Cross-Sections Standards: Extending and Updating

International Nuclear Information System (INIS)

Pronyaev, V.; Carlson, A.D.; Capote Noy, R.; Wallner, A.

2011-03-01

The meeting participants have considered the progress in the measurement and evaluation of neutron cross sections and spectra which can be used as standard or reference data. This includes extension of the 197 Au(n,γ) standard to the energy range below 200 keV, 235 U(n th ,f) prompt fission neutron spectrum and neutron induced gamma-production cross sections. The work on this data development project for next two years has been agreed. (author)

Neutron detection efficiency determinations for the TUNL neutron-neutron and neutron-proton scattering-length measurements

International Nuclear Information System (INIS)

Trotter, D.E. Gonzalez; Meneses, F. Salinas; Tornow, W.; Crowell, A.S.; Howell, C.R.; Schmidt, D.; Walter, R.L.

2009-01-01

The methods employed and the results obtained from measurements and calculations of the detection efficiency for the neutron detectors used at Triangle Universities Nuclear Laboratory (TUNL) in the simultaneous determination of the 1 S 0 neutron-neutron and neutron-proton scattering lengths a nn and a np , respectively, are described. Typical values for the detector efficiency were 0.3. Very good agreement between the different experimental methods and between data and calculation has been obtained in the neutron energy range below E n =13MeV.

Neutron scattering and the 30 S ribosomal subunit of E. coli

International Nuclear Information System (INIS)

Moore, P.B.; Engelman, D.M.; Langer, J.A.; Ramakrishnan, V.R.; Schindler, D.G.; Schoenborn, B.P.; Sillers, I.Y.; Yabuki, S.

1982-01-01

This paper reviews the progress made in the study of the internal organization of the 30 S ribosomal subunit of E. coli by neutron scattering since 1975. A map of that particle showing the position of 14 of the subunit's 21 proteins is presented, and the methods currently used for collecting and analyzing such data are discussed. Also discussed is the possibility of extending the interpretation of neutron mapping data beyond the limits practical today. 30 references, 5 figures

Bulk hydrogen analysis, using neutrons. Final report of the second research co-ordination meeting

International Nuclear Information System (INIS)

1998-11-01

The aims of the Second Co-ordination Meting (RCM) of the Coordinated Research Programme (CRP) were to report on and review progress against the work programme set at the beginning of the CRP and to discuss the work plans for the second half of the programme. In many cases hydrogen is required to be measured in a bulk medium rather than merely at a surface. For this reason neutrons are used due to their high penetrating power in dense material. In addition, the mass attenuation coefficient for neutrons in hydrogen is significantly larger than for all other elements, meaning that neutrons have a higher probability of interacting with hydrogen than with other elements in the sample matrix. Neutrons have been used in the following areas: Fast Neutron Transmission, Scattering and Activation Technique; Digital Neutron Imaging; Hydrogen Detection by Epithermal Neutrons; Microscopic Behaviour of Hydrogen in Bulk Materials

Nuclei in a neutron star

International Nuclear Information System (INIS)

Oyamatsu, K.; Yamada, M.

1994-01-01

We report on the recent progress in understanding the matter in the crust of a neutron star. For nuclides in the outer crust, recently measured masses of neutron-rich nuclei enable us to determine more accurately the stable nuclide as a function of the matter density. In the inner crust, the compressible liquid-drop model predicts successive change of the nuclear shape, from sphere to cylinder, slab, cylindrical hole and spherical hole at densities just before the transition to uniform matter. In order to go beyond the liquiddrop model, we performed the Thomas-Fermi calculation paying special attention to the surface diffuseness, and have recently calculated the shell energies of the non-spherical nuclei. We have found from these studies that all these non-spherical nuclei exist stably in the above order even if we include the surface diffuseness and shell energies. (author)

Neutron beams for the study of condensed matter: a view of the first half-century

International Nuclear Information System (INIS)

Bacon, G.E.

1982-01-01

Neutron diffraction was first demonstrated in 1936 but awaited the development of the nuclear reactor before becoming a practical technique for the study of condensed matter. Neutrons have unique advantages for the location of hydrogen atoms, the recognition of magnetic architecture and the study of crystal vibrations and atomic and molecular motions. The techniques available exploit the optical properties of neutrons over a wavelength range from 0.5 to 500 A. Progress has gone hand in hand with a steady increase of reactor flux over 50 years but future improvements may depend on pulsed linear accelerators as the source of neutrons. (author)

Surface damage in the small intestine of the mouse after X - or neutron irradiation

International Nuclear Information System (INIS)

Hamlet, R.; Carr, K.E.; Nias, A.H.; Watt, C.

1981-01-01

Damage after X-irradiation includes lateral villous collapse, progressing after 3 - 5 days to villi which sometimes show signs of vertical collapse. After neutron irradiation vertical villous collapse is established earlier, with less swelling of villous tips. It seems, therefore, that at radiobiologically equivalent doses, neutron and X-irradiation produce different levels of surface damage, with neutron irradiation being the more destructive. Early villous tip damage may perhaps be due to disruption of susceptible cells already at the extrusion zone, or to stromal damage

Neutron detection efficiency determinations for the TUNL neutron-neutron and neutron-proton scattering-length measurements

Energy Technology Data Exchange (ETDEWEB)

Trotter, D.E. Gonzalez [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)], E-mail: crowell@tunl.duke.edu; Meneses, F. Salinas [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Tornow, W. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)], E-mail: tornow@tunl.duke.edu; Crowell, A.S.; Howell, C.R. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Schmidt, D. [Physikalisch-Technische Bundesanstalt, D-38116, Braunschweig (Germany); Walter, R.L. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)

2009-02-11

The methods employed and the results obtained from measurements and calculations of the detection efficiency for the neutron detectors used at Triangle Universities Nuclear Laboratory (TUNL) in the simultaneous determination of the {sup 1}S{sub 0} neutron-neutron and neutron-proton scattering lengths a{sub nn} and a{sub np}, respectively, are described. Typical values for the detector efficiency were 0.3. Very good agreement between the different experimental methods and between data and calculation has been obtained in the neutron energy range below E{sub n}=13MeV.

KURRI progress report 1999. April 1999 - March 2000

International Nuclear Information System (INIS)

2000-01-01

The KUR (Kyoto-University Reactor) was operated 1,462 hours though some troubles happened at control rods in the fiscal year of 1999. In the same time, we accepted 6,082 man-day researchers for their experiments and scientific meeting at KURRI (Kyoto-University Research Reactor Institute). Two international symposia supported by KURRI on the neutron radiography and on the environmental plutonium were also held in the year. Kyoto University Critical Assembly (KUCA) was celebrated for its 25th anniversary on 10th March 2000. During 25 years 1,652 students came from outside to take the educational program of KUCA, which was open to all Japanese university graduate courses. The progress report compiles one-page briefings of research activities by authors on following 10 categories: 1) Slow Neutron Physics and Neutron Scattering (22 authors). 2) Nuclear Physics and Nuclear Data (12 authors). The 6 papers among them are on Project Research on Systematic Studies of Neutron Rich Nuclei by Using ISOL (Isotope Separator On-Line). 3) Reactor Physics and Reactor Engineering (9 authors). 4) Material Science and Radiation Effect (42 authors). Project Research on the Condensed Matter by Use of Nuclear Probe includes 10 papers, and Project Research on Material Irradiation Effect under Controlled Irradiation Fields includes 10 papers. 5) Geochemistry and Environmental Science (29 authors). The 4 papers among them are on Project Research on Ultra-Low-Level Environmental Radio-Nuclide Analysis. 6) Life-Science and Medical Science (18 authors). Project Research on Non-Equilibrium Radical Process in Biological Molecule System includes 5 papers, and Project Research on Biological Effects of Intermediate Energy Neutron of the KUR Facility on the Mammalian Cells includes 3 papers. 7) Neutron Capture Therapy (26 authors). 8) Neutron Radiography and Radiation Application (4 authors). 9) TRU and Nuclear Chemistry (14 authors). The 9 papers among them are on Project Research on Nuclear and

Annual progress report on nuclear data 1983 of the Central Bureau for Nuclear Measurements, Geel (Belgium)

International Nuclear Information System (INIS)

1984-05-01

In this progress report of the Central Bureau for Nuclear Measurements at Geel (Belgium) researches related to neutron data and to non-neutron nuclear data are gathered. Neutron data are essentially related to cross-section measurements: for instance, concerning actinides, structural materials as Cr and Fe, fission products. Some studies are classified as concerning standard neutron data. Underlying physics is no forgotten neither than equipment (linear accelerator). Non-neutron nuclear data is concerned essentially with decay studies. Some compilations and evaluations are also given. Improvement of measurement and source preparation techniques is a part of this section

Neutron stars

International Nuclear Information System (INIS)

Irvine, J.M.

1978-01-01

The subject is covered in chapters entitled: introduction (resume of stellar evolution, gross characteristics of neutron stars); pulsars (pulsar characteristics, pulsars as neutron stars); neutron star temperatures (neutron star cooling, superfluidity and superconductivity in neutron stars); the exterior of neutron stars (the magnetosphere, the neutron star 'atmosphere', pulses); neutron star structure; neutron star equations of state. (U.K.)

Applied nuclear data research and development. Semiannual progress report, April 1-September 30, 1983

International Nuclear Information System (INIS)

Arthur, E.D.

1984-06-01

This progress report describes the activities of the Los Alamos Nuclear Data Group for April 1, 1983 through September 30, 1983. Topics covered include theory and evaluation of nuclear cross sections; nuclear cross-section processing and testing; neutron activation; fission products, and actinides; and core neutronics code development in support of LMFBR carbide core assessment

KURRI progress report 1993. April 1993 - March 1994

International Nuclear Information System (INIS)

1994-10-01

In this third issue of the KURRI Progress Report, the summaries of Project Researches which started in fiscal year 1993 are included. These research areas fit in the five research areas which are pursued with priority in the future activities utilizing the KUR. The reactor KUR added 1600 h of operation during the past fiscal year, and the operation hours reached 227.4 Gh. 160 research works were added, and the total number became 4817. 1860 visiting researchers were accepted during the year, and the total number became 49,809. In the field of boron neutron capture therapeutics, 14 more patients were treated, which brought the total to 44. Now, there are 5 medical teams performing this therapy. The Atomic Energy Commission compiled the new 'Long term program for research, development and utilization of nuclear energy' in June, 1994. The research activities on slow neutron physics and neutron scattering, nuclear physics and nuclear chemistry, reactor physics and reactor engineering, material science and radiation effects, geochemistry and environmental science, life science and medical science, neutron capture therapy, neutron radiography and radiation application and radioactive waste management and health physics are reported. (K.I.)

A dense plasma focus-based neutron source for a single-shot detection of illicit materials and explosives by a nanosecond neutron pulse

International Nuclear Information System (INIS)

Gribkov, V A; Latyshev, S V; Miklaszewski, R A; Chernyshova, M; Drozdowicz, K; Wiacek, U; Tomaszewski, K; Lemeshko, B D

2010-01-01

Recent progress in a single-pulse Nanosecond Impulse Neutron Investigation System (NINIS) intended for interrogation of hidden objects by means of measuring elastically scattered neutrons is presented in this paper. The method uses very bright neutron pulses having duration of the order of 10 ns only, which are generated by dense plasma focus (DPF) devices filled with pure deuterium or DT mixture as a working gas. The small size occupied by the neutron bunch in space, number of neutrons per pulse and mono-chromaticity (ΔE/E∼1%) of the neutron spectrum provides the opportunity to use a time-of-flight (TOF) technique with flying bases of about a few metres. In our researches we used DPF devices having bank energy in the range 2-7 kJ. The devices generate a neutron yield of the level of 10 8 -10 9 2.45 MeV and 10 10 -10 11 14 MeV neutrons per pulse with pulse duration ∼10-20 ns. TOF base in the tests was 2.2-18.5 m. We have demonstrated the possibility of registering of neutrons scattered by the substances under investigation-1 litre bottles with methanol (CH 3 OH), phosphoric (H 2 PO 4 ) and nitric (HNO 3 ) acids as well as a long object-a 1 m gas tank filled with deuterium at high pressure. It is shown that the above mentioned short TOF bases and relatively low neutron yields are enough to distinguish different elements' nuclei composing the substance under interrogation and to characterize the geometry of lengthy objects in some cases. The wavelet technique was employed to 'clean' the experimental data registered. The advantages and restrictions of the proposed and tested NINIS technique in comparison with other methods are discussed.

Communication of nuclear data progress: No.8 (1992)

International Nuclear Information System (INIS)

1992-12-01

Communication of nuclear data progress (CNDP) in English is set up by Chinese Nuclear Data Center (CNDC). This is the eighth issue. It includes the measurements of secondary neutron spectra on 9 Be, the cross section and angular distribution of 40 Ca(n, α) reaction, 54 V decay data and 107 Ag(α, n) cross section; the theoretical calculations of neutron induced reaction data on 56 Fe, 238 U and proton induced reaction data on 89 Y and 241 Am; the charged particle data evaluation of 235 U; and some papers on atomic and molecular data and data processing

Neutron damage of silicon detectors at 20 deg C

International Nuclear Information System (INIS)

Bardos, R.; Gorfine, G.; Guy, L.; Moorhead, G.; Taylor, G.; Tovey, S.

1992-01-01

This contribution reports new data on the damage of silicon detectors by low energy (1 MeV) neutrons. The data were taken at the end of 1991. Three exposures of UA2 Inner Silicon detectors were made: at +20 deg C, -15 deg C and -95 deg C. A high neutron flux enabled the required fluences to be achieved in relatively short times. This increases the sensitivity of the experiment to damage types with shorter self-annealing time constants. This note discusses the new data taken at +20 deg C. Analysis of the low temperature exposures is in progress. 5 refs., 15 figs

Applied nuclear data research and development. Semiannual progress report, April 1-September 30, 1983

Energy Technology Data Exchange (ETDEWEB)

Arthur, E.D. (comp.)

1984-06-01

This progress report describes the activities of the Los Alamos Nuclear Data Group for April 1, 1983 through September 30, 1983. Topics covered include theory and evaluation of nuclear cross sections; nuclear cross-section processing and testing; neutron activation; fission products, and actinides; and core neutronics code development in support of LMFBR carbide core assessment. (GHT)

Progress report 1981 - 1983

International Nuclear Information System (INIS)

Eder, G.; Rauch, H.; Balcar, E.; Buchtela, K.; Schwertfuehrer, W.; Vana, N.

1984-06-01

This progress report describes the research activities of the Atom-institute of the Austrian Universities of the period 1981-1983. The chapter headings are: (1) Electron- and X-ray physics, thermoluminescence and archeometry. (2) Nuclear physics. (3) Nuclear techniques, electronics and EDP. (4) Neutron- and solid state physics with neutron scattering, low temperature physics, theoretical solid state physics and preparation technique. (5) Radiation chemistry. (6) Radiation protection and dosimetry. Each chapter gives a comprimated overview about the research work done in the described period, illustrated by diagrams and tables, a comprehensive list of publications, each citation provided with an (mostly English) Abstract and a comprehensive list of thesis, which are completed or under preparation in the corresponding working group. Additional chapters give lists of educational work, verbal presentation, cooperations with other institutions and personnel. An annex of photos gives an additional impression of the institute. (A.N.)

Operational experiences of the spallation neutron source superconducting linac and power ramp-up

International Nuclear Information System (INIS)

Kim, Sang-Ho

2009-01-01

The spallation neutron source (SNS) is a second generation pulsed neutron source and designed to provide a 1-GeV, 1.44-MW proton beam to a mercury target for neutron production. Since the commissioning of the accelerator complex in 2006, the SNS has started its operation for neutron production and beam power ramp-up has been in progress toward the design goal. All subsystems of the SNS were designed and developed for substantial improvements compared to existing accelerators because the design beam power is almost an order of magnitude higher compared to existing neutron facilities and the achievable neutron scattering performance will exceed present sources by more than a factor of 20 to 100. In this paper, the operational experiences with the SNS Superconducting Linac (SCL), Power Ramp-up Plan to reach the design goal and the Power Upgrade Plan (PUP) will be presented including machine, subsystem and beam related issues.

Communication of nuclear data progress

International Nuclear Information System (INIS)

2006-07-01

This is the 30th issue of Communication of Nuclear Data Progress (CNDP), in which the progress and achievements in nuclear data field in China during 2004 are carried. It includes the evaluations and model calculations of neutron data for n+ 31 P, 59 Co, 92-106 Mo, Nat-116 Cd, 233 U and the covariance data evaluation of experimental data for 27 Al, update the decay data for radionuclide 7 Be. Some results of studies for nuclear evaluation tool and model are also included in this issue, i.e. reaction mechanism studies of 5 He, a new method of evaluating the discrepant data, linear fit of correlative data by least squared method et al. (authors)

Advisory Committee for the calibration standards of ionizing radiation measurement. Section 3. Neutron measurements

International Nuclear Information System (INIS)

1980-01-01

Section III (Neutron measurements) of the Comite Consultatif pour les Etalons de Mesure des Rayonnements ionisants held its fourth meeting in April 1979. After discussing the final report on the fast neutron fluence rate intercomparison, it requested BIPM to submit it for publication in Metrologia. Section III studied the state-of-the-art of an international comparison of a 252 Cf (10 7 s -1 ) source which is in progress. A new fast neutron fluence rate intercomparison is scheduled for 1980; the energies and the methods to be used have been investigated. Finally, Section III studied carefully and rewrote a proposal for a 14-MeV neutron dosimetry facility at BIPM, and added a Recommendation for CCEMRI [fr

Pulsed neutron sources for epithermal neutrons

International Nuclear Information System (INIS)

Windsor, C.G.

1978-01-01

It is shown how accelerator based neutron sources, giving a fast neutron pulse of short duration compared to the neutron moderation time, promise to open up a new field of epithermal neutron scattering. The three principal methods of fast neutron production: electrons, protons and fission boosters will be compared. Pulsed reactors are less suitable for epithermal neutrons and will only be briefly mentioned. The design principle of the target producing fast neutrons, the moderator and reflector to slow them down to epithermal energies, and the cell with its beam tubes and shielding will all be described with examples taken from the new Harwell electron linac to be commissioned in 1978. A general comparison of pulsed neutron performance with reactors is fraught with difficulties but has been attempted. Calculation of the new pulsed source fluxes and pulse widths is now being performed but we have taken the practical course of basing all comparisons on extrapolations from measurements on the old 1958 Harwell electron linac. Comparisons for time-of-flight and crystal monochromator experiments show reactors to be at their best at long wavelengths, at coarse resolution, and for experiments needing a specific incident wavelength. Even existing pulsed sources are shown to compete with the high flux reactors in experiments where the hot neutron flux and the time-of-flight methods can be best exploited. The sources under construction can open a new field of inelastic neutron scattering based on energy transfer up to an electron volt and beyond

Neutron scattering at FRJ-2. Experimental reports 2004

International Nuclear Information System (INIS)

Brueckel, T.; Richter, D.; Zorn, R.

2004-01-01

The Research Centre FZ-Juelich is offering its neutron research facilities to a growing national and international user community for the benefit of their research using neutron beams. FZ-Juelich operates a 23 MW DIDO reactor that delivers a total neutron flux of 2.9 x 10 14 n/cm 2 s (undisturbed) for a comprehensive suite of 17 instruments installed at 5 individual thermal beam tubes and, in addition, 5 external cold neutron guides. In the year 2004 the reactor was in operation for 208 days and we are happy to announce that more than 150 individual experiments (constituting 61% of the total) were carried out by a large external user community from 85 institutions all over the world. In close collaboration with internal staff the study of soft matter systems took the largest stake. In addition, subjects of biology, magnetism and engineering were among the other main topics of the experimental programme. We gratefully acknowledge the funding programme ''Juelich Neutrons for Europe'' under the European initiative NMI3 that enables numerous external users from the EU and associated countries to come over, visit Juelich and perform their experiments. This book comprises the scientific reports of the experiments completed in 2004. We wish to thank all external users, local applicants, instrument responsibles, and technical staff for their joint efforts and contributions to the success and progress of the Juelich neutron research facility. (orig.)

Neutron radiography using neutron imaging plate

International Nuclear Information System (INIS)

Chankow, Nares; Wonglee, Sarinrat

2008-01-01

Full text: The aims of this research are to study properties of neutron imaging plate, to obtain a suitable condition for neutron radiography and to use the neutron imaging plate for testing of materials nondestructively. The experiments were carried out by using a neutron beam from the Thai Research Reactor TRR-1/M1 at a power of 1.2 MW. A BAS-ND 2040 FUJI neutron imaging plate and a MX125 Kodak X-ray film/Gadolinium neutron converter screen combination were tested for comparison. It was found that the photostimulated light (PSL) read out of the imaging plate was directly proportional to the exposure time. It was also found that radiography with neutron using the imaging plate was approximately 40 times faster than the conventional neutron radiography using x-ray film/Gd converter screen combination. The sensitivity of the imaging plate to gamma-rays was investigated by using gamma-rays from an 192 Ir and a 60 Co radiographic sources. The imaging plate was found to be 5-6 times less sensitive to gamma-rays than a FUJI BAS-MS 2040 gamma-ray imaging plate. Finally, some specimens were selected to be radiographed with neutrons using the imaging plate and the x-ray film/Gd converter screen combination in comparison to x-rays. Parts containing light elements could be clearly observed by the two neutron radiographic techniques. It could be concluded that the image quality from the neutron imaging plate was comparable to the conventional x-ray film/Gd converter screen combination but the exposure time could be approximately reduced by a factor of 40

Testing the Formation Scenarios of Binary Neutron Star Systems with Measurements of the Neutron Star Moment of Inertia

Science.gov (United States)

Newton, William G.; Steiner, Andrew W.; Yagi, Kent

2018-03-01

Two low-mass (M slope of the nuclear symmetry energy L. We find that, if either J0737-3039B or the J1756-2251 companion were formed in a US-SN, no more than 0.06 M ⊙ could have been lost from the progenitor core. Furthermore, a measurement of the moment of inertia of J0737-3039A to within 10% accuracy can discriminate between formation scenarios and, given current constraints on the predicted core mass loss, potentially rule them out. Advanced LIGO can potentially measure the neutron star tidal polarizability to equivalent accuracy which, using the I-Love-Q relations, would obtain similar constraints on the formation scenarios. Such information would help constrain important aspects of binary evolution used for population synthesis predictions of the rate of binary neutron star mergers and resulting electromagnetic and gravitational wave signals. Further progress needs to be made in modeling the core-collapse process that leads to low-mass neutron stars, particularly in making robust predictions for the mass loss from the progenitor core.

Ultracold neutrons

International Nuclear Information System (INIS)

Steenstrup, S.

Briefly surveys recent developments in research work with ultracold neutrons (neutrons of very low velocity, up to 10 m/s at up to 10 -7 eV and 10 -3 K). Slow neutrons can be detected in an ionisation chamber filled with B 10 F 3 . Very slow neutrons can be used for investigations into the dipole moment of neutrons. Neutrons of large wave length have properties similar to those of light. The limit angle for total reflection is governed by the wave length and by the material. Total reflection can be used to filter ultracold neutrons out of the moderator material of a reactor. Total reflection can also be used to store ultracold neutrons but certain problems with storage have not yet been clarified. Slow neutrons can be made to lose speed in a neutron turbine, and come out as ultracold neutrons. A beam of ultracold neutrons could be used in a neutron microscope. (J.S.)

Basic research of neutron radiography using cold neutron beam

International Nuclear Information System (INIS)

Oda, Masahiro; Tamaki, Masayoshi; Tasaka, Kanji

1995-01-01

As the result of demanding high quality images, now the nuclear reactors which can supply stably intense neutron beam have become the most general neutron source for radiography. For the purpose, mostly thermal neutrons have been used, but it is indispensable to use other neutrons than thermal neutrons for advancing neutron radiography technology and expanding the application fields. The radiography using cold neutrons is most behind in the development because the suitable neutron source was not available in Japan. The neutron sources for exclusively obtaining intense cold neutron beam were installed in the Kyoto University reactor in 1986 and in the JRR-3M of Japan Atomic Energy Research Institute in 1991. Basically as neutron energy lowers, the cross section of substances increases. In certain crystalline substances, the Bragg cutoff arises. The removal of scattered neutrons, the measurement of parallelism of beam and the relation of the thickness of objects with the transmissivity of cold neutrons are described. The imaging by TV method and the cold neutron CT in the CNRF and the simplified neutron CT by film method are reported. (K.I.)

Neutron diffraction technique as a method for material studies

International Nuclear Information System (INIS)

Belhorma, B.; Labrim, H.; Gandou, Z.

2010-01-01

The Morocco's first Nuclear Research has been constructed in CNESTEN. The reactor divergence has been tested, and the nominal power of 2MW was successfully achieved. The reactor has 4 beam ports two of them are projected for neutron scattering. Such technique allows studying the crystallographic and magnetic structures of materials using the thermal neutrons produced in the reactor. the powder diffractometer has been designed. Component reception and installation procedures are in progress. The second experiment consists on small angle neutron scattering that allows the study of soft matter and polymers in the range of 1-50 nm. The third technique that can complete the two previous is the 4-circle neutron spectrometry which is designed mainly to study structural properties of the mono-crystalline material and texture.This technique is complementary to the X-ray diffraction already available in CNESTEN. Some applications of this technique are: --to determine the crystallographic and magnetic structure of polycrystalline materials.-- to study the texture in metals and alloys.-- to perform holography measurement

Status of nuclear data for use in neutron therapy

International Nuclear Information System (INIS)

White, R.M.

1992-03-01

Optimization of neutron therapy requires nuclear cross section data for: (1) the selection of source reaction for neutron production, (2) the design of collimators and shields, (3) the calculation of absorbed dose in the irradiation tissues, including heterogeneity corrections, (4) microdosimetry, and (5) studies of the influence of radiation quality on biological effects. Under the auspices of the International Atomic Energy Agency (IAEA), a Coordinated Research Program (CRP) has been underway since 1987 to assess the status of these nuclear data, to coordinate research efforts, to report recent progress, and to recommend acceptance of appropriate data and further research where necessary. In this paper, we outline the results of the CRP's final report to be published and evaluate the status of the most critical nuclear data needs for therapy, i.e., kerma calculations and measurements, from low neutron energies to 70 MeV. Recommended values for (n,p) kerma and the carbon-to-oxygen neutron kerma factor ratios up to 70 MeV are given with estimates of their current uncertainties

Geant4 simulations of NIST beam neutron lifetime experiment

Science.gov (United States)

Valete, Daniel; Crawford, Bret; BL2 Collaboration Collaboration

2017-09-01

A free neutron is unstable and its decay is described by the Standard Model as the transformation of a down quark into an up quark through the weak interaction. Precise measurements of the neutron lifetime test the validity of the theory of the weak interaction and provide useful information for the predictions of the theory of Big Bang nucleosynthesis of the primordial helium abundance in the universe and the number of different types of light neutrinos Nν. The predominant experimental methods for determination of the neutron lifetime are commonly called `beam' and `bottle' methods, and the most recent uses of each method do not agree with each other within their stated uncertainties. An improved experiment of the beam technique, which uses magnetic and electric fields to trap and guide the decay protons of a beam of cold neutrons to a detector, is in progress at the National Institute of Standards and Technology, Gaithersburg, MD with a precision goal of 0.1. I acknowledge the support of the Cross-Diciplinary Institute at Gettysburg College.

Non-destructive assay of 242Pu by resonance neutron capture

International Nuclear Information System (INIS)

Kane, W.R.; Lu, Ming-Shih; Aronson, A.; Forman, L.; Vanier, P.E.

1995-01-01

For the accurate assay of plutonium by neutron correlation measurements, especially for material derived from high-burnup reactor fuel, the content of 242 Pu in a sample must be determined. Since 242 Pu has a long half-life (387,000 yr) and decays to 238 U by alpha particle emission with the accompanying emission of only weak, low-energy gamma rays, gamma-ray spectrometry methods which are ordinarily employed to determine the isotopic composition of a plutonium sample are not feasible for 242 Pu. The existence of a resonance in the neutron capture cross section of 242 Pu at an energy of 2.67 electron volts (eV) with a large (72, 000 barn) cross section affords the possibility for the quantitative assay of this isotope by epithermal neutron capture. Essential for this purpose is an appropriately designed geometry of neutron moderators and absorbers which will provide maximum flux in the eV region while suppressing thermal neutron capture by the fissile plutonium isotopes. Signatures for neutron capture in 242 Pu include the decay of 243 Pu (4.9 hr), prompt capture gamma rays (total energy 5.034 MeV), and the decay of an isomeric state (330 nanosecond). Experiments to determine the feasibility of this approach are currently in progress

Status of the intense pulsed neutron source

International Nuclear Information System (INIS)

Brown, B.S.; Carpenter, J.M.; Crawford, R.K.; Rauchas, A.V.; Schulke, A.W.; Worlton, T.G.

1988-01-01

IPNS is not unique in having concerns about the level of funding, and the future looks good despite these concerns. This report details the progress made at IPNS during the last two years. Other papers in these proceedings discuss in detail the status of the enriched uranium Booster target, the two instruments that are under construction, GLAD and POSY II, and a proposal for research on an Advanced Pulsed Neutron Source (ASPUN) that has been submitted to the Department of Energy (DOE). Further details on IPNS are available in the IPNS Progress Report 1987--1988, available by writing the IPNS Division Office. 9 refs., 3 tabs

Neutron stars as cosmic neutron matter laboratories

International Nuclear Information System (INIS)

Pines, D.

1986-01-01

Recent developments which have radically changed our understanding of the dynamics of neutron star superfluids and the free precession of neutron stars are summarized, and the extent to which neutron stars are cosmic neutron matter laboratories is discussed. 17 refs., 1 tab

Progress on solid breeder TBM at SWIP

International Nuclear Information System (INIS)

Feng, K.M.; Pan, C.H.; Zhang, G.S.; Luo, T.Y.; Zhao, Z.; Chen, Y.J.; Ye, X.F.; Hu, G.; Wang, P.H.; Yuan, T.; Feng, Y.J.; Xiang, B.; Zhang, L.; Wang, Q.J.; Cao, Q.X.; Li, Z.X.; Wang, F.

2010-01-01

Current progress on the design and R and D of Chinese helium-cooled solid breeder test blanket module, CN HCSB TBM is presented. The updated design on structural, neutronics, thermal-hydraulics and safety analysis has been completed. In order to accommodate the HCSB TBM ancillary system, the design and necessary R and Ds corresponding sub-systems have being developed. Current status on the development of function materials, structure material and the helium test loop are also presented. The Chinese low-activation ferritic/martensitic steels CLF-1, which is the structural material for the HCSB TBM is being manufactured by industry. The neutron multiplier Be and tritium breeder Li 4 SiO 4 pebbles are being prepared in laboratory scale.

Evolution of the nondestructive testing equipment for neutron radiography in the framework of the programs of the Services des Piles de Saclay

International Nuclear Information System (INIS)

1980-10-01

The progress made in neutron radiography testing equipment is made with respect to (a) the devices located inside reactor ponds (collimation, leak-tightness, irradiation devices, detection systems), (b) neutron radiography of active parts outside the reactor ponds (testing of fuel rods several metres long by a neutron radiography system by dry feed through), (3) neutron radiography on inactive materials (fitting an axial channel and a side channel in the Triton reactor), (4) neutron radiography on a neutron guide set up at the end of the Neutron Guide Hall associated with the Orphee reactor, i.e. 70 metres from it [fr

Progress Report Oct to Dec 1975(2)

International Nuclear Information System (INIS)

1976-01-01

Progress report NO. 2 of Tehran Nuclear Research Centre outlines a brief description of the progress made in each section of the centre. A complete list of dissertations for Master's degrees studied at the Nuclear Research Centre and a list of new technical employee are given at the beginning of the report. Research activities in the third section include, isotope separation, laser research, radiation chemistry, reactor management, environmental research, neutron physics, reactor engineering, and nuclear medicine. The fourth section deals with education and training; technical support and health physics are discussed in sections five and six respectively

Method and device for optimizing the measurements of the damping characteristics of therman neutrons

International Nuclear Information System (INIS)

Jacobson, L.A.; Johnstone, C.W.

1978-01-01

The borehole probe consists of a pulsed neutron generator and two detectors installed at different distances from the generator. The decay or damping characteristics of the thermal neutrons in a ground formation are measured by picking up indications of the concentration of thermal neutrons in the formation during a set of two measuring intervals offer irradiation. These measuring intervals consist of a sequence of discrete time gates. The time gates are subdivided into groups of progressive periods of time. The time delay between the pulses and the beginning of the sequence is adjusted by means of a selected scale factor value. (DG) [de

The 7th Japan-Taiwan joint meeting on neutron and X-ray scattering. Proceedings

International Nuclear Information System (INIS)

2016-03-01

The 7th Japan-Taiwan joint meeting on neutron and X-ray scattering in Kumatori is held bilaterally in Japan and Taiwan. This meeting provides the recent outstanding results in the fields of fundamental polymer and biological sciences and their applications as well. In the fields of the X-ray and/or neutron scattering, the methodological progress expands the research fields and gives us new scientific insights. This meeting invites the researchers developing new methodologies, such as dynamics measurement utilizing nuclear Bragg resonance, subunit-kinetics measurement with deuteration-assisted small-angle neutron scattering and so on. (J.P.N.)

Communication of nuclear data progress: No.4(1990)

International Nuclear Information System (INIS)

1990-12-01

Communication of Nuclear Data Progress (CNDP) in English is set up by Chinese Nuclear Committee and Chinese Nuclear Data Center (CNDC). This is the fourth issue. It includes measurements of neutron smaee angle scattering cross sections for Fe, Ni and Cr; n-D scattering phase-shift and 17 O R-matrix analyses; calculations of neutron elastic and inclastic scattering from 7 Li; evaluations of 2 H(n,2n), 23 Na, 59 Co(n, γ), 235,238 U, 239 Pu(n,f) and (n, γ) cross sections; and a fitting code of corrected SLBW with multlievel effect (CBNFIT); R-matrix analysis code (RAC) etc

Nuclear structure from radioactive decay. Annual progress report

International Nuclear Information System (INIS)

Wood, J.L.

1982-01-01

The most exciting development during this year has been the formulation of a unified description of shape coexistence in nuclei. The picture is built on the idea that deformation in nuclei is due to an attractive proton-neutron force acting in the valence shell model space. The excitation of nucleon pairs across closed shells effectively increases the number of valence nucleons, giving rise to a set of coexisting states with larger deformation. The major area of activity is the study of neutron-deficient nuclei around the Z = 82 shell closure, with special emphasis on the levels of the odd-mass Pt, Au, Hg and Tl isotopes. Progress is reported

Status of neutron monitoring meters for radiation protection purpose

International Nuclear Information System (INIS)

Li Taosheng

2003-01-01

The status of and trends towards the development of neutron monitoring meters, such as dose survey meter, workplace (ambient) spectrometer and individual dosimeters, are discussed in the present paper from the perspectives of workplace and individual dose monitoring. Over the past 4 decades, both neutron dose survey meter and workplace spectrometer have declined to be more reasonable in design of their probes, with more broaden applications. With the development of electronic technology, there is a trend towards being more small-compacted and smart. Although many technical difficulties in the practical measurement, some significant progresses have be made in the development and research of these kinds of meters. (authors)

Polarized neutrons

International Nuclear Information System (INIS)

Williams, W.G.

1988-01-01

The book on 'polarized neutrons' is intended to inform researchers in condensed matter physics and chemistry of the diversity of scientific problems that can be investigated using polarized neutron beams. The contents include chapters on:- neutron polarizers and instrumentation, polarized neutron scattering, neutron polarization analysis experiments and precessing neutron polarization. (U.K.)

Inelastic neutron scattering of H2 adsorbed in HKUST-1

International Nuclear Information System (INIS)

Liu, Y.; Brown, C.M.; Neumann, D.A.; Peterson, V.K.; Kepert, C.J.

2007-01-01

A series of inelastic neutron scattering (INS) investigations of hydrogen adsorbed in activated HKUST-1 (Cu 3 (1,3,5-benzenetricarboxylate) 2 ) result in INS spectra with rich features, even at very low loading ( 2 :Cu). The distinct inelastic features in the spectra show that there are three binding sites that are progressively populated when the H 2 loading is less than 2.0 H 2 :Cu, which is consistent with the result obtained from previous neutron powder diffraction experiments. The temperature dependence of the INS spectra reveals the relative binding enthalpies for H 2 at each site

Measurement of 241Am Ground State Radiative Neutron Capture Cross Section with Cold Neutron Beam. Progress Report on Research Contract HUN14318 for the CRP on Minor Actinide Neutron Reaction Data (MANREAD)

International Nuclear Information System (INIS)

Belgya, T.; Szentmiklosi, L.; Kis, Z.; Nagy, N.M.; Konya, J.

2012-01-01

The ground state cross section of 242 Am has been measured with beams of cold neutrons at the Budapest Research Reactor using the X-ray emission of the decay product of 242 Pu. This methodology avoids the uncertainty caused by resonance neutrons in the pile activations. The target was characterized with gamma and X-ray spectrometry. The obtained ground state cross section is 540 ± 32 b, which is at the low end of the most recent literature values, but agrees with most of them within their uncertainty. (author)

Neutron spectra produced by moderating an isotopic neutron source

International Nuclear Information System (INIS)

Carrillo Nunnez, Aureliano; Vega Carrillo, Hector Rene

2001-01-01

A Monte Carlo study has been carried out to determine the neutron spectra produced by an isotopic neutron source inserted in moderating media. Most devices used for radiation protection have a response strongly dependent on neutron energy. ISO recommends several neutron sources and monoenergetic neutron radiations, but actual working situations have broad spectral neutron distributions extending from thermal to MeV energies, for instance, near nuclear power plants, medical applications accelerators and cosmic neutrons. To improve the evaluation of the dosimetric quantities, is recommended to calibrate the radiation protection devices in neutron spectra which are nearly like those met in practice. In order to complete the range of neutron calibrating sources, it seems useful to develop several wide spectral distributions representative of typical spectra down to thermal energies. The aim of this investigation was to use an isotopic neutron source in different moderating media to reproduce some of the neutron fields found in practice. MCNP code has been used during calculations, in these a 239PuBe neutron source was inserted in H2O, D2O and polyethylene moderators. Moderators were modeled as spheres and cylinders of different sizes. In the case of cylindrical geometry the anisotropy of resulting neutron spectra was calculated from 0 to 2 . From neutron spectra dosimetric features were calculated. MCNP calculations were validated by measuring the neutron spectra of a 239PuBe neutron source inserted in a H2O cylindrical moderator. The measurements were carried out with a multisphere neutron spectrometer with a 6LiI(Eu) scintillator. From the measurements the neutron spectrum was unfolded using the BUNKIUT code and the UTA4 response matrix. Some of the moderators with the source produce a neutron spectrum close to spectra found in actual applications, then can be used during the calibration of radiation protection devices

Communication of nuclear data progress

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-07-15

This is the 30th issue of Communication of Nuclear Data Progress (CNDP), in which the progress and achievements in nuclear data field in China during 2004 are carried. It includes the evaluations and model calculations of neutron data for n+{sup 31}P, {sup 59}Co, {sup 92-106}Mo, {sup Nat-116}Cd, {sup 233}U and the covariance data evaluation of experimental data for {sup 27}Al, update the decay data for radionuclide {sup 7}Be. Some results of studies for nuclear evaluation tool and model are also included in this issue, i.e. reaction mechanism studies of {sup 5}He, a new method of evaluating the discrepant data, linear fit of correlative data by least squared method et al. (authors)

Fast rigorous numerical method for the solution of the anisotropic neutron transport problem and the NITRAN system for fusion neutronics application. Pt. 2

International Nuclear Information System (INIS)

Takahashi, A.; Rusch, D.

1979-10-01

The I*-method, which is a non-approximative treatment of the neutron balance equations by the use of double-differential cross sections and a generalized angular transfer probability, is realized within the NITRAN system. It is shown, by means of test calculations for assemblies related to fusion reactor neutronics that double-differential cross section data provide substantial progress in transport problems with kinematically complicated reaction channels like (n,2n), (n,n'γ), and (n,n'α), because the I*-method is free from kinematic assumptions. The properties of the exponential method to generate the supplementary equations to the SN equations are investigated. (orig.) [de

Neutron beam design for low intensity neutron and gamma-ray radioscopy using small neutron sources

CERN Document Server

Matsumoto, T

2003-01-01

Two small neutron sources of sup 2 sup 5 sup 2 Cf and sup 2 sup 4 sup 1 Am-Be radioisotopes were used for design of neutron beams applicable to low intensity neutron and gamma ray radioscopy (LINGR). In the design, Monte Carlo code (MCNP) was employed to generate neutron and gamma ray beams suited to LINGR. With a view to variable neutron spectrum and neutron intensity, various arrangements were first examined, and neutron-filter, gamma-ray shield and beam collimator were verified. Monte Carlo calculations indicated that with a suitable filter-shield-collimator arrangement, thermal neutron beam of 3,900 ncm sup - sup 2 s sup - sup 1 with neutron/gamma ratio of 7x10 sup 7 , and 25 ncm sup - sup 2 s sup - sup 1 with very large neutron/gamma ratio, respectively, could be produced by using sup 2 sup 5 sup 2 Cf(122 mu g) and a sup 2 sup 4 sup 1 Am-Be(37GBq)radioisotopes at the irradiation port of 35 cm from the neutron sources.

Neutron cooling and cold-neutron sources (1962); Refroidissement des neutrons et sources de neutrons froids (1962)

Energy Technology Data Exchange (ETDEWEB)

Jacrot, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1962-07-01

Intense cold-neutron sources are useful in studying solids by the inelastic scattering of neutrons. The paper presents a general survey covering the following aspects: a) theoretical considerations put forward by various authors regarding thermalization processes at very low temperatures; b) the experiments that have been carried out in numerous laboratories with a view to comparing the different moderators that can be used; c) the cold neutron sources that have actually been produced in reactors up to the present time, and the results obtained with them. (author) [French] Des sources intenses de neutrons froids sont utiles pour l'etude des solides par diffusion inelastique des neutrons. On presente une revue d'ensemble: a) des considerations theoriques faites par divers auteurs sur les processus de thermalisation a tres basse temperature; b) des experiences faites dans de nombreux laboratoires pour comparer les divers moderateurs possibles; c) des sources de neutrons froids effectivement realisees dans des piles a ce jour, et des resultats obtenus avec ces sources. (auteur)

Indigenous development of diamond detectors for monitoring neutrons

International Nuclear Information System (INIS)

Singh, Arvind; Amit Kumar; Topkar, Anita; Pithawa, C.K.

2013-01-01

2 =.998. The tests carried out confirm the suitability of these detectors as a fast neutron detector for counting applications. The tests of the detector at higher neutron fluxes are in progress. (author)

Nuclear and radiochemical techniques in chemical analysis. Progress report, June 1, 1975--July 31, 1976

International Nuclear Information System (INIS)

Finston, H.L.; Williams, E.T.

1976-01-01

There has been significant progress on the project to measure the neutron-capture cross sections of reactor produced radionuclides, in particular, centering on the problems with nuclides such as 22 Na which may have a resonance for thermal-neutron capture. The thermal capture cross section of less than 40 b has been verified for 54 Mn, and cadmium ratios have been determined for 184 Re in the V-11 and V-14 positions in the HFBR. Lutetium has been used as a neutron temperature monitor for the Brookhaven reactors. Preliminary results on the project to determine the effect of chemical state on the branching ratio in 58 Co are reported. Procedures for aerosol collection and analysis by proton-induced x-ray emission (PIXE) are reported. A program to analyze aerosols for polycyclic aromatic hydrocarbons has been initiated. Progress is reported on the experimental verification of the proposed acid-base hypothesis

Radiation transport. Progress report, April 1-December 31, 1983

International Nuclear Information System (INIS)

O'Dell, R.D.

1984-10-01

Research and development progress in radiation transport by the Los Alamos National Laboratory's Group X-6 for the last nine months of CY 83 is reported. Included are unclassified tasks in the areas of Fission Reactor Neutronics, Deterministic Transport Methods, Monte Carlo Radiation Transport, and Cross Sections and Physics

Progress on RMC: a Monte Carlo neutron transport code for reactor analysis

International Nuclear Information System (INIS)

Wang, Kan; Li, Zeguang; She, Ding; Liu, Yuxuan; Xu, Qi; Shen, Huayun; Yu, Ganglin

2011-01-01

This paper presents a new 3-D Monte Carlo neutron transport code named RMC (Reactor Monte Carlo code), specifically intended for reactor physics analysis. This code is being developed by Department of Engineering Physics in Tsinghua University and written in C++ and Fortran 90 language with the latest version of RMC 2.5.0. The RMC code uses the method known as the delta-tracking method to simulate neutron transport, the advantages of which include fast simulation in complex geometries and relatively simple handling of complicated geometrical objects. Some other techniques such as computational-expense oriented method and hash-table method have been developed and implemented in RMC to speedup the calculation. To meet the requirements of reactor analysis, the RMC code has the calculational functions including criticality calculation, burnup calculation and also kinetics simulation. In this paper, comparison calculations of criticality problems, burnup problems and transient problems are carried out using RMC code and other Monte Carlo codes, and the results show that RMC performs quite well in these kinds of problems. Based on MPI, RMC succeeds in parallel computation and represents a high speed-up. This code is still under intensive development and the further work directions are mentioned at the end of this paper. (author)

Neutron radiobiology. Summary of a workshop

International Nuclear Information System (INIS)

1978-01-01

This report is a summary of a workshop held in June 1977 at Oak Ridge National Laboratory to evaluate the progress of research in the field of neutron radiobiology. The participants reviewed the results of current research and identified unresolved questions and areas of uncertainty. They then defined areas in which additional research should be undertaken, and, finally, they reviewed ways in which results from current and projected research could be applied to inform and influence regulatory decisions

The emergence of the dimensions and fundamental forces in the universe, an information-theoretical approach for the expaining of the quantity ratios of the fundamental interactions. 2. rev. and enl. ed.

International Nuclear Information System (INIS)

Ganter, Bernd

2013-01-01

After a description of the four fundamental inteactions and the connection of information with energy the principle of the fast maximation together with the Ganter tableau is described. Then as example the derivation of the value of the fine-structure constant from the Ganter tableau is described. Thereafter the extension of the Ganter tableau, further properties of the Ganter tableau, and the persuasion of the Ganter tableau are considered. (HSI)

The emergence of the dimensions and fundamental forces in the universe, an information-theoretical approach for the expaining of the quantity ratios of the fundamental interactions. 2. rev. and enl. ed.; Die Entstehung der Dimensionen und Grundkraefte im Universum, ein informationstheoretischer Ansatz zur Erklaerung der Groessenverhaeltnisse der Fundamentalen Wechselwirkungen

Energy Technology Data Exchange (ETDEWEB)

Ganter, Bernd

2013-06-01

After a description of the four fundamental inteactions and the connection of information with energy the principle of the fast maximation together with the Ganter tableau is described. Then as example the derivation of the value of the fine-structure constant from the Ganter tableau is described. Thereafter the extension of the Ganter tableau, further properties of the Ganter tableau, and the persuasion of the Ganter tableau are considered. (HSI)

Local control of murine melanoma xenografts in nude mice by neutron capture therapy

International Nuclear Information System (INIS)

Allen, B.J.; Corderoy-Buck, S.; Moore, D.E.; Mishima, Y.; Ichihashi, M.

1992-01-01

In recent years considerable progress has been made in the development and implementation of neutron capture therapy (NCT) for the treatment of cancer. In particular, the boron analogue of the melanin precursor phenylalanine, i.e., DL-p-boronophenylalanine (BPA), has been used to demonstrate the regression and cure of Harding-Passey (HP) melanoma in syngeneic mice. However, 18 to 25% cures were obtained for neutron irradiations without boron, suggesting that the neutron dose alone plays an important role. Neutron capture therapy of B-16 melanoma xenografts in nude mice showed substantial tumor regression over 35 days, but the survival rate of NCT treated mice after 7 weeks was only 40-60%. In this paper the authors demonstrate the equivalence of the nude mouse model with a syngeneic model, using the same Harding-Passey murine melanoma line, and delineate the conditions required for maximum differential response between neutron irradiation with and without BPA administration, with complete local control as the end point

Neutron radiography

International Nuclear Information System (INIS)

Hrdlicka, Z.

1977-01-01

Neutron radiography is a radiographic method using a neutron beam of a defined geometry. The neutron source usually consists of a research reactor, a specialized neutron radiography reactor or the 252 Cf radioisotope source. There are two types of the neutron radiography display system, viz., a system producing neutron radiography images by a photographic process or a system allowing a visual display, eg., using a television monitor. The method can be used wherever X-ray radiography is used except applications in the radiography of humans. The neutron radiography unit at UJV uses the WWR-S reactor as the neutron source and both types of the above mentioned display system. (J.P.)

Neutron matter, neutron pairing, and neutron drops based on chiral effective field theory interactions

Energy Technology Data Exchange (ETDEWEB)

Krueger, Thomas

2016-10-19

The physics of neutron-rich systems is of great interest in nuclear and astrophysics. Precise knowledge of the properties of neutron-rich nuclei is crucial for understanding the synthesis of heavy elements. Infinite neutron matter determines properties of neutron stars, a final stage of heavy stars after a core-collapse supernova. It also provides a unique theoretical laboratory for nuclear forces. Strong interactions are determined by quantum chromodynamics (QCD). However, QCD is non-perturbative at low energies and one presently cannot directly calculate nuclear forces from it. Chiral effective field theory circumvents these problems and connects the symmetries of QCD to nuclear interactions. It naturally and systematically includes many-nucleon forces and gives access to uncertainty estimates. We use chiral interactions throughout all calculation in this thesis. Neutron stars are very extreme objects. The densities in their interior greatly exceed those in nuclei. The exact composition and properties of neutron stars is still unclear but they consist mainly of neutrons. One can explore neutron stars theoretically with calculations of neutron matter. In the inner core of neutron stars exist very high densities and thus maybe exotic phases of matter. To investigate whether there exists a phase transition to such phases even at moderate densities we study the chiral condensate in neutron matter, the order parameter of chiral symmetry breaking, and find no evidence for a phase transition at nuclear densities. We also calculate the more extreme system of spin-polarised neutron matter. With this we address the question whether there exists such a polarised phase in neutron stars and also provide a benchmark system for lattice QCD. We find spin-polarised neutron matter to be an almost non-interacting Fermi gas. To understand the cooling of neutron stars neutron pairing is of great importance. Due to the high densities especially triplet pairing is of interest. We

The Los Alamos Neutron Science Center Spallation Neutron Sources

International Nuclear Information System (INIS)

Nowicki, Suzanne F.; Wender, Stephen A.; Mocko, Michael

2017-01-01

The Los Alamos Neutron Science Center (LANSCE) provides the scientific community with intense sources of neutrons, which can be used to perform experiments supporting civilian and national security research. These measurements include nuclear physics experiments for the defense program, basic science, and the radiation effect programs. This paper focuses on the radiation effects program, which involves mostly accelerated testing of semiconductor parts. When cosmic rays strike the earth's atmosphere, they cause nuclear reactions with elements in the air and produce a wide range of energetic particles. Because neutrons are uncharged, they can reach aircraft altitudes and sea level. These neutrons are thought to be the most important threat to semiconductor devices and integrated circuits. The best way to determine the failure rate due to these neutrons is to measure the failure rate in a neutron source that has the same spectrum as those produced by cosmic rays. Los Alamos has a high-energy and a low-energy neutron source for semiconductor testing. Both are driven by the 800-MeV proton beam from the LANSCE accelerator. The high-energy neutron source at the Weapons Neutron Research (WNR) facility uses a bare target that is designed to produce fast neutrons with energies from 100 keV to almost 800 MeV. The measured neutron energy distribution from WNR is very similar to that of the cosmic-ray-induced neutrons in the atmosphere. However, the flux provided at the WNR facility is typically 5×107 times more intense than the flux of the cosmic-ray-induced neutrons. This intense neutron flux allows testing at greatly accelerated rates. An irradiation test of less than an hour is equivalent to many years of neutron exposure due to cosmic-ray neutrons. The low-energy neutron source is located at the Lujan Neutron Scattering Center. It is based on a moderated source that provides useful neutrons from subthermal energies to ~100 keV. The characteristics of these sources

The Los Alamos Neutron Science Center Spallation Neutron Sources

Science.gov (United States)

Nowicki, Suzanne F.; Wender, Stephen A.; Mocko, Michael

The Los Alamos Neutron Science Center (LANSCE) provides the scientific community with intense sources of neutrons, which can be used to perform experiments supporting civilian and national security research. These measurements include nuclear physics experiments for the defense program, basic science, and the radiation effect programs. This paper focuses on the radiation effects program, which involves mostly accelerated testing of semiconductor parts. When cosmic rays strike the earth's atmosphere, they cause nuclear reactions with elements in the air and produce a wide range of energetic particles. Because neutrons are uncharged, they can reach aircraft altitudes and sea level. These neutrons are thought to be the most important threat to semiconductor devices and integrated circuits. The best way to determine the failure rate due to these neutrons is to measure the failure rate in a neutron source that has the same spectrum as those produced by cosmic rays. Los Alamos has a high-energy and a low-energy neutron source for semiconductor testing. Both are driven by the 800-MeV proton beam from the LANSCE accelerator. The high-energy neutron source at the Weapons Neutron Research (WNR) facility uses a bare target that is designed to produce fast neutrons with energies from 100 keV to almost 800 MeV. The measured neutron energy distribution from WNR is very similar to that of the cosmic-ray-induced neutrons in the atmosphere. However, the flux provided at the WNR facility is typically 5×107 times more intense than the flux of the cosmic-ray-induced neutrons. This intense neutron flux allows testing at greatly accelerated rates. An irradiation test of less than an hour is equivalent to many years of neutron exposure due to cosmic-ray neutrons. The low-energy neutron source is located at the Lujan Neutron Scattering Center. It is based on a moderated source that provides useful neutrons from subthermal energies to ∼100 keV. The characteristics of these sources, and

Radiation protection commissioning of neutron beam instruments at the OPAL research reactor

International Nuclear Information System (INIS)

Parkes, Alison; Saratsopoulos, John; Deura, Michael; Kenny, Pat

2008-01-01

The neutron beam facilities at the 20 MW OPAL Research Reactor were commissioned in 2007 and 2008. The initial suite of eight neutron beam instruments on two thermal neutron guides, two cold neutron guides and one thermal beam port located at the reactor face, together with their associated shielding were progressively installed and commissioned according to their individual project plans. Radiation surveys were systematically conducted as reactor power was raised in a step-wise manner to 20 MW in order to validate instrument shielding design and performance. The performance of each neutron guide was assessed by neutron energy spectrum and flux measurements. The activation of beam line components, decay times assessments and access procedures for Bragg Institute beam instrument scientists were established. The multiple configurations for each instrument and the influence of operating more than one instrument or beamline simultaneously were also tested. Areas of interest were the shielding around the secondary shutters, guide shield and bunker shield interfaces and monochromator doors. The shielding performance, safety interlock checks, improvements, radiation exposures and related radiation protection challenges are discussed. This paper discusses the health physics experience of commissioning the OPAL Research Reactor neutron beam facilities and describes health physics results, actions taken and lessons learned during commissioning. (author)

Workshop on polarized neutron filters and polarized pulsed neutron experiments

International Nuclear Information System (INIS)

Itoh, Shinichi

2004-07-01

The workshop was held in KEK by thirty-three participants on April 26, 2004. The polarized neutron filter method was only discussed. It consists of three parts; the first part was discussed on the polarized neutron methods, the second part on the polarized neutron experiments and the third on the pulse neutron spectrometer and polarized neutron experiments. The six papers were presented such as the polarized 3 He neutron spin filter, neutron polarization by proton polarized filter, soft master and neutron scattering, polarized neutron in solid physics, polarization experiments by chopper spectroscope and neutron polarization system in superHRPD. (S.Y.)

Physics Division progress report for period ending June 30, 1981

International Nuclear Information System (INIS)

1981-11-01

Progress is reported in detail in the following areas: Holifield Heavy-Ion Research Facility, nuclear physics, the UNISOR program, neutron physics, theoretical physics, the Nuclear Data Project, atomic and plasma physics, and high energy physics. Publications are listed. Separate abstracts were prepared for 34 papers

Fail-safe neutron shutter used for thermal neutron radiography

International Nuclear Information System (INIS)

Sachs, R.D.; Morris, R.A.

1976-11-01

A fail-safe, reliable, easy-to-use neutron shutter was designed, built, and put into operation at the Omega West Reactor, Los Alamos Scientific Laboratory. The neutron shutter will be used primarily to perform thermal neutron radiography, but is also available for a highly collimated source of thermal neutrons [neutron flux = 3.876 x 10 6 (neutrons)/(cm 2 .s)]. Neutron collimator sizes of either 10.16 by 10.16 cm or 10.16 by 30.48 cm are available

Constructing a neutron star from the lattice in G{sub 2}-QCD

Energy Technology Data Exchange (ETDEWEB)

Hajizadeh, Ouraman; Maas, Axel [University of Graz, Institute of Physics, NAWI Graz (Austria)

2017-10-15

The inner structure of neutron stars is still an open question. One obstacle is the infamous sign problem of lattice QCD, which bars access to the high-density equation of state. A possibility to make progress and understand the qualitative impact of gauge interactions on the neutron star structure is to study a modified version of QCD without the sign problem. In the modification studied here the gauge group of QCD is replaced by the exceptional Lie group G{sub 2}, which keeps neutrons in the spectrum. Using an equation of state from lattice calculations only we determine the mass-radius-relation for a neutron star using the Tolman-Oppenheimer-Volkoff equation. This allows us to understand the challenges and approximations currently necessary to use lattice data for this purpose. We discuss in detail the particular uncertainties and systematic problems of this approach. (orig.)

Progress in design of the SNS linac

International Nuclear Information System (INIS)

Hardekopf, R.

2001-01-01

The Spallation Neutron Source (SNS) is a six-laboratory collaboration to build an intense pulsed neutron facility at Oak Ridge, TN. The linac design has evolved from the conceptual design presented in 1997 in order to achieve higher initial performance and to incorporate desirable upgrade features. The linac is now designed to produce 2-MW beam power using a combination of radio-frequency quadrupole (RFQ) linac, drift-tube linac (DTL), coupled-cavity linac (CCL), and superconducting-RF (SRF) linac. Designs of each of these elements support he high peak intensity and high quality beam required for injection into the SNS accumulator ring. This paper will trace the evolution of the linac design and the progress made in the R and D program. (author)

ORNL Neutron Sciences Annual Report for 2007

Energy Technology Data Exchange (ETDEWEB)

Anderson, Ian S [ORNL; Horak, Charlie M [ORNL; Counce, Deborah Melinda [ORNL; Ekkebus, Allen E [ORNL

2008-07-01

This is the first annual report of the Oak Ridge National Laboratory Neutron Sciences Directorate for calendar year 2007. It describes the neutron science facilities, current developments, and future plans; highlights of the year's activities and scientific research; and information on the user program. It also contains information about education and outreach activities and about the organization and staff. The Neutron Sciences Directorate is responsible for operation of the High Flux Isotope Reactor and the Spallation Neutron Source. The main highlights of 2007 were highly successful operation and instrument commissioning at both facilities. At HFIR, the year began with the reactor in shutdown mode and work on the new cold source progressing as planned. The restart on May 16, with the cold source operating, was a significant achievement. Furthermore, measurements of the cold source showed that the performance exceeded expectations, making it one of the world's most brilliant sources of cold neutrons. HFIR finished the year having completed five run cycles and 5,880 MWd of operation. At SNS, the year began with 20 kW of beam power on target; and thanks to a highly motivated staff, we reached a record-breaking power level of 183 kW by the end of the year. Integrated beam power delivered to the target was 160 MWh. Although this is a substantial accomplishment, the next year will bring the challenge of increasing the integrated beam power delivered to 887 MWh as we chart our path toward 5,350 MWh by 2011.

Extraction of the neutron-neutron scattering length ann from kinematically complete neutron-deuteron breakup experiments

International Nuclear Information System (INIS)

Witala, H.; Hueber, D.; Gloeckle, W.; Tornow, W.; Gonzalez Trotter, D.E.

1996-01-01

Data for the neutron-neutron final-state-interaction cross section obtained recently in a kinematically complete neutron-deuteron breakup experiment have been reanalyzed using rigorous solutions of the three-nucleon Faddeev equations with realistic nucleon-nucleon interactions. A discrepancy was found with respect to a recent analysis based on the W-matrix approximation to the Paris potential. We also estimate theoretical uncertainties in extracting the neutron-neutron scattering length resulting from the use of different nucleon-nucleon interactions and the possible action of the two pion-exchange three-nucleon force. We find that there exists a certain production angle for the interacting neutron-neutron pair where the uncertainties become minimal. (author)

Neutron Absorbing Ability Variation in Neutron Absorbing Material Caused by the Neutron Irradiation in Spent Fuel Storage Facility

Energy Technology Data Exchange (ETDEWEB)

Sohn, Hee Dong; Han, Seul Gi; Lee, Sang Dong; Kim, Ki Hong; Ryu, Eag Hyang; Park, Hwa Gyu [Doosan Heavy Industries and Construction, Changwon (Korea, Republic of)

2014-10-15

In spent fuel storage facility like high density spent fuel storage racks and dry storage casks, spent fuels are stored with neutron absorbing materials installed as a part of those facilities, and they are used for absorbing neutrons emitted from spent fuels. Usually structural material with neutron absorbing material of racks and casks are located around spent fuels, so it is irradiated by neutrons for long time. Neutron absorbing ability could be changed by the variation of nuclide composition in neutron absorbing material caused by the irradiation of neutrons. So, neutron absorbing materials are continuously faced with spent fuels with boric acid solution or inert gas environment. Major nuclides in neutron absorbing material are Al{sup 27}, C{sup 12}, B{sup 11}, B{sup 10} and they are changed to numerous other ones as radioactive decay or neutron absorption reaction. The B{sup 10} content in neutron absorbing material dominates the neutron absorbing ability, so, the variation of nuclide composition including the decrease of B{sup 10} content is the critical factor on neutron absorbing ability. In this study, neutron flux in spent fuel, the activation of neutron absorbing material and the variation of nuclide composition are calculated. And, the minimum neutron flux causing the decrease of B{sup 10} content is calculated in spent fuel storage facility. Finally, the variation of neutron multiplication factor is identified according to the one of B{sup 10} content in neutron absorbing material. The minimum neutron flux to impact the neutron absorbing ability is 10{sup 10} order, however, usual neutron flux from spent fuel is 10{sup 8} order. Therefore, even though neutron absorbing material is irradiated for over 40 years, B{sup 10} content is little decreased, so, initial neutron absorbing ability could be kept continuously.

Communication of nuclear data progress: No.16 (1996)

International Nuclear Information System (INIS)

1996-12-01

'Communication of Nuclear Data Progress' (CNDP) in English is set up by Chinese Nuclear Data Center. This is the 16th issue. The nuclear data achievements and progress in China during the last year are presented. It includes the measurements of neutron activation cross section for 193 Ir(n,2n) 192m2 Ir reaction at 14.7 MeV and fragment angular distributions in the fission of 197 Au, 207 Pb and 209 Bi induced by alpha particles up to 70 MeV; discrete level effect on spectrum calculations of secondary particles, calculations of n + 235 U (E n = 5 MeV) scattering angle distribution by ECIS95 and various cross sections for n + 169 Tm and 103 Rh reactions up to 100 MeV and 25 MeV respectively, and p + 52 Cr reactions up to 30 MeV; evaluations of H total neutron cross section from 20 MeV to 2 GeV and 169 Tm(n,xn) 168,167,166,165 Tm reactions from threshold to 100 MeV, evaluation and calculation of production cross sections for 11 C, 13 N and 15 O medical radioisotopes from 11 B, 13 C, 15 N(p,n) and 16 O(p,x) 13 N reactions up to 80 MeV; an approach of systematic description of gamma-ray spectra from (n,xγ) reactions induced by fast neutron; data files of optical model parameter and level density sub-libraries

Taking into account the Earth's rotation in experiments on search for the electric dipole moment of neutron

International Nuclear Information System (INIS)

Silenko, A.Ya.

2007-01-01

Analysis of the problem of taking into account the Earth's rotation in a search for the electric dipole moment (EDM) of the neutron in experiments with ultracold neutrons and in a diffractional experiment is fulfilled. Taking into account the Earth's rotation in the diffractional experiment gives an exactly calculated correction which is negligible as compared with the accuracy reached at present time. In the experiments with ultracold neutrons, the correction is greater than the systematical error and the exact calculation of it needs further investigation. In this connection, further developments of diffractional method would considerably promote progress in the search for the electric dipole moment of the neutron

Neutron optics using transverse field neutron spin echo method

International Nuclear Information System (INIS)

Achiwa, Norio; Hino, Masahiro; Yamauchi, Yoshihiro; Takakura, Hiroyuki; Tasaki, Seiji; Akiyoshi, Tsunekazu; Ebisawa, Toru.

1993-01-01

A neutron spin echo (NSE) spectrometer with perpendicular magnetic field to the neutron scattering plane, using an iron yoke type electro-magnet has been developed. A combination of cold neutron guider, supermirror neutron polarizer of double reflection type and supermirror neutron analyser was adopted for the spectrometer. The first application of the NSE spectrometer to neutron optics by passing Larmor precessing neutrons through gas, solid and liquid materials of several different lengths which are inserted in one of the precession field have been examined. Preliminary NSE spectra of this sample geometry are discussed. (author)

Neutronics Benchmarks for the Utilization of Mixed-Oxide Fuel: Joint U.S./Russian Progress Report for Fiscal Year 1997 Volume 2-Calculations Performed in the United States

Energy Technology Data Exchange (ETDEWEB)

Primm III, RT

2002-05-29

This volume of the progress report provides documentation of reactor physics and criticality safety studies conducted in the US during fiscal year 1997 and sponsored by the Fissile Materials Disposition Program of the US Department of Energy. Descriptions of computational and experimental benchmarks for the verification and validation of computer programs for neutron physics analyses are included. All benchmarks include either plutonium, uranium, or mixed uranium and plutonium fuels. Calculated physics parameters are reported for all of the computational benchmarks and for those experimental benchmarks that the US and Russia mutually agreed in November 1996 were applicable to mixed-oxide fuel cycles for light-water reactors.

Neutronics Benchmarks for the Utilization of Mixed-Oxide Fuel: Joint U.S./Russian Progress Report for Fiscal Year 1997 Volume 2-Calculations Performed in the United States

International Nuclear Information System (INIS)

Primm III, RT

2002-01-01

This volume of the progress report provides documentation of reactor physics and criticality safety studies conducted in the US during fiscal year 1997 and sponsored by the Fissile Materials Disposition Program of the US Department of Energy. Descriptions of computational and experimental benchmarks for the verification and validation of computer programs for neutron physics analyses are included. All benchmarks include either plutonium, uranium, or mixed uranium and plutonium fuels. Calculated physics parameters are reported for all of the computational benchmarks and for those experimental benchmarks that the US and Russia mutually agreed in November 1996 were applicable to mixed-oxide fuel cycles for light-water reactors

Design status of an intense 14 MeV neutron source for cancer therapy

CERN Document Server

Yao, Z E; Cheng, S W; Jia, W B

2002-01-01

Design and development of an intense 14 MeV neutron source for cancer therapy is in progress at the Institute of Nuclear Research of Lanzhou University. The neutrons from the T(d,n) sup 4 He reaction are produced by bombarding a rotating titanium tritide target with a 40 mA deuteron beam at 600 keV. The designed neutron yield is 8x10 sup 1 sup 2 n/s and the maximum dose rate at a 100 cm source-to-skin distance is 25 cGy/min. The HV terminal, accelerating column and HV power supply are enclosed inside a stainless steel pressure vessel containing 6 atm SF sub 6 gas to provide the electrical insulation.

Neutron radiography

International Nuclear Information System (INIS)

Hiraoka, Eiichi

1988-01-01

The thermal neutron absorption coefficient is essentially different from the X-ray absorption coefficient. Each substance has a characteristic absorption coefficient regardless of its density. Neutron deams have the following features: (1) neutrons are not transmitted efficiently by low molecular weight substances, (2) they are transmitted efficiently by heavy metals, and (3) the transmittance differs among isotopes. Thus, neutron beams are suitable for cheking for foreign matters in heavy metals and testing of composites consisting of both heavy and light materials. A neutron source generates fast neutrons, which should be converted into thermal neutrons by reducing their energy. Major neutron souces include nuclear reactors, radioisotopes and particle accelerators. Photographic films and television systems are mainly used to observe neutron transmission images. Computers are employed for image processing, computerized tomography and three-dimensional analysis. The major applications of neutron radiography include inspection of neclear fuel; evaluation of material for airplane; observation of fuel in the engine and oil in the hydraulic systems in airplanes; testing of composite materials; etc. (Nogami, K.)

Physics Division progress report for period ending June 30, 1981

Energy Technology Data Exchange (ETDEWEB)

1981-11-01

Progress is reported in detail in the following areas: Holifield Heavy-Ion Research Facility, nuclear physics, the UNISOR program, neutron physics, theoretical physics, the Nuclear Data Project, atomic and plasma physics, and high energy physics. Publications are listed. Separate abstracts were prepared for 34 papers. (WHK)

A small angle neutron scattering study of thermoplastic elastomer

Energy Technology Data Exchange (ETDEWEB)

Sutiarso,; Edy Giri, R Putra; Andon, Insani; Sudirman,; Sudaryanto, [Materials Science Research Centre, National Atomic Energy Agency, Jakarta (Indonesia)

1998-10-01

A bilateral scientific cooperation, in the small angle neutron scattering has been agreed upon between CIAE, China and BATAN, Indonesia as well as MINT Malaysia. As stated in the agreed proposal that the objective of this cooperation, in the initial stage (stage-1), was to have a regional intercomparison measurements of SANS instruments in order to determine their characteristic/performance. Therefore, this report is supposed to describe the progress in the SANS instrument development of each country involved during the period of 1996/97 and some activities related to the SANS instrument. Since, up to now, we have not yet received any progresses reported from either China or Malaysia, this report will describe the progress of SANS`s activities in BATAN only. (author)

Neutron Dosimetry

International Nuclear Information System (INIS)

Vanhavere, F.

2001-01-01

The objective of SCK-CEN's R and D programme on neutron dosimetry is to improve the determination of neutron doses by studying neutron spectra, neutron dosemeters and shielding adaptations. In 2000, R and D focused on the contiued investigation of the bubble detectors type BD-PND and BDT, in particular their sensitivity and temperature dependence; the updating of SCK-CEN's criticality dosemeter, the investigation of the characteristics of new thermoluminescent materials and their use in neutron dosemetry; and the investigation of neutron shielding

Neutron-electron EDM correlations in supersymmetry and prospects for EDM searches

International Nuclear Information System (INIS)

Abel, Steven A.; Lebedev, Oleg

2006-01-01

Motivated by recent progress in experimental techniques of electric dipole moment (EDM) measurements, we study correlations between the neutron and electron EDMs in common supersymmetric models. These include minimal supergravity (mSUGRA) with small CP phases, mSUGRA with a heavy SUSY spectrum, the decoupling scenario and split SUSY. In most cases, the electron and neutron EDMs are found to be observable in the next round of EDM experiments. They exhibit certain correlation patterns. For example, if d n ∼ 10 -27 e cm is found, d e is predicted to lie in the range 10 -28 -10 -29 e cm

Neutron-electron EDM correlations in supersymmetry and prospects for EDM searches

International Nuclear Information System (INIS)

Abel, S.A.

2005-08-01

Motivated by recent progress in experimental techniques of electric dipole moment (EDM) measurements, we study correlations between the neutron and electron EDMs in common supersymmetric models. These include minimal supergravity (mSUGRA) with small CP phases, mSUGRA with a heavy SUSY spectrum, the decoupling scenario and split SUSY. In most cases, the electron and neutron EDMs are found to be observable in the next round of EDM experiments. They exhibit certain correlation patterns. For example, if d n ∝ 10 -27 e cm is found, d e is predicted to lie in the range 10 -28 - 10 -29 e cm. (orig.)

Neutron Dosimetry

Energy Technology Data Exchange (ETDEWEB)

Vanhavere, F

2001-04-01

The objective of SCK-CEN's R and D programme on neutron dosimetry is to improve the determination of neutron doses by studying neutron spectra, neutron dosemeters and shielding adaptations. In 2000, R and D focused on the contiued investigation of the bubble detectors type BD-PND and BDT, in particular their sensitivity and temperature dependence; the updating of SCK-CEN's criticality dosemeter, the investigation of the characteristics of new thermoluminescent materials and their use in neutron dosemetry; and the investigation of neutron shielding.

Design and fabrication of 4π Clover Detector Array Assembly for gamma-spectroscopy studies using thermal neutrons

International Nuclear Information System (INIS)

Kumar, Manish; Kamble, S.R.; Chaudhari, A.T.; Sabharwal, T.P.; Pathak, Kavindra; Prasad, N.K.; Kinage, L.A.; Biswas, D.C.; Bhagwat, P.V.

2017-01-01

Nuclear spectroscopy has been studied earlier from the measurement of prompt gamma rays produced in reactions with thermal neutrons from CIRUS reactor. For studying the prompt γ-spectroscopy using thermal neutrons from Dhruva Reactor, BARC, the development of a dedicated beam line (R-3001) is in progress. In this beam line a detector assembly consisting of Clover Ge detectors will be used. This experimental setup will be utilized to investigate nuclear structure using prompt (n,γ) reactions and also to study the spectroscopy of neutron-rich fission-fragment nuclei

Neutronic analysis of JET external neutron monitor response

Energy Technology Data Exchange (ETDEWEB)

Snoj, Luka, E-mail: luka.snoj@ijs.si [Reactor Physics Division, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Lengar, Igor; Čufar, Aljaž [Reactor Physics Division, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Syme, Brian; Popovichev, Sergey [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, OX14 3DB, United Kingdom (United Kingdom); Batistoni, Paola [ENEA C. R. Frascati, via E. Fermi 45, 00044 Frascati, Roma (Italy); Conroy, Sean [VR Association, Uppsala University, Department of Physics and Astronomy, PO Box 516, SE-75120 Uppsala (Sweden)

2016-11-01

Highlights: • We model JET tokamak containing JET remote handling system. • We investigate effect of remote handling system on external neutron monitor response. • Remote handling system correction factors are calculated. • Integral correction factors are relatively small, i.e up to 8%. - Abstract: The power output of fusion devices is measured in terms of the neutron yield which relates directly to the fusion yield. JET made a transition from Carbon wall to ITER-Like Wall (Beryllium/Tungsten/Carbon) during 2010–11. Absolutely calibrated measurement of the neutron yield by JET neutron monitors was ensured by direct measurements using a calibrated {sup 252}Cf neutron source (NS) deployed by the in-vessel remote handling system (RHS) inside the JET vacuum vessel. Neutronic calculations were required in order to understand the neutron transport from the source in the vacuum vessel to the fission chamber detectors mounted outside the vessel on the transformer limbs of the tokamak. We developed a simplified computational model of JET and the JET RHS in Monte Carlo neutron transport code MCNP and analyzed the paths and structures through which neutrons reach the detectors and the effect of the JET RHS on the neutron monitor response. In addition we performed several sensitivity studies of the effect of substantial massive structures blocking the ports on the external neutron monitor response. As the simplified model provided a qualitative picture of the process only, some calculations were repeated using a more detailed full 3D model of the JET tokamak.

Optimizing Neutron Thermal Scattering Effects in very High Temperature Reactors. Final Report

International Nuclear Information System (INIS)

Hawari, Ayman

2014-01-01

This project aims to develop a holistic understanding of the phenomenon of neutron thermalization in the VHTR. Neutron thermalization is dependent on the type and structure of the moderating material. The fact that the moderator (and reflector) in the VHTR is a solid material will introduce new and interesting considerations that do not apply in other (e.g. light water) reactors. The moderator structure is expected to undergo radiation induced changes as the irradiation (or burnup) history progresses. In this case, the induced changes in structure will have a direct impact on many properties including the neutronic behavior. This can be easily anticipated if one recognizes the dependence of neutron thermalization on the scattering law of the moderator. For the pebble bed reactor, it is anticipated that the moderating behavior can be tailored, e.g. using moderators that consist of composite materials, which could allow improved optimization of the moderator-to-fuel ratio.

Investigation of Response of Several Neutron Surveymeters by a DT Neutron Generator

International Nuclear Information System (INIS)

Kim, Sang In; Jang, In Su; Kim, Jang Lyul; Lee, Jung IL; Kim, Bong Hwan

2012-01-01

Several neutron measuring devices were tested under the neutron fields characterized with two distinct kinds of thermal and fast neutron spectrum. These neutron fields were constructed by the mixing of both thermal neutron fields and fast neutron fields. The thermal neutron field was constructed using by a graphite pile with eight AmBe neutron sources. The fast neutron field of 14 MeV was made by a DT neutron generator. In order to change the fraction of fast neutron fluence rate in each neutron fields, a neutron generator was placed in the thermal neutron field at 50 cm and 150 cm from the reference position. The polyethylene neutron collimator was used to make moderated 14 MeV neutron field. These neutron spectra were measured by using a Bonner sphere system with an LiI scintillator, and dosimetric quantities delivered to neutron surveymeters were determined from these measurement results.

Intraoperative boron neutron capture therapy for malignant gliomas. First clinical results of Tsukuba phase I/II trial using JAERI mixed thermal-epithermal beam

International Nuclear Information System (INIS)

Matsumura, A.; Yamamoto, T.; Shibata, Y.

2000-01-01

Since October 1999, a clinical trial of intraoperative boron neutron capture therapy (IOBNCT) is in progress at JRR-4 (Japan Research Reactor-4) in Japan Atomic Energy Research Institute (JAERI) using mixed thermal-epithermal beam (thermal neutron beam I: TNB-I). Compared to pure thermal beam (thermal neutron beam II: TNB-II), TNB-I has an improved neutron delivery into the deep region than TNB-II. The clinical protocol and the preliminary results will be discussed. (author)

Neutron Imaging at Compact Accelerator-Driven Neutron Sources in Japan

Directory of Open Access Journals (Sweden)

Yoshiaki Kiyanagi

2018-03-01

Full Text Available Neutron imaging has been recognized to be very useful to investigate inside of materials and products that cannot be seen by X-ray. New imaging methods using the pulsed structure of neutron sources based on accelerators has been developed also at compact accelerator-driven neutron sources and opened new application fields in neutron imaging. The world’s first dedicated imaging instrument at pulsed neutron sources was constructed at J-PARC in Japan owing to the development of such new methods. Then, usefulness of the compact accelerator-driven neutron sources in neutron science was recognized and such facilities were newly constructed in Japan. Now, existing and new sources have been used for neutron imaging. Traditional imaging and newly developed pulsed neutron imaging such as Bragg edge transmission have been applied to various fields by using compact and large neutron facilities. Here, compact accelerator-driven neutron sources used for imaging in Japan are introduced and some of their activities are presented.

Accelerator based neutron source for neutron capture therapy

International Nuclear Information System (INIS)

Salimov, R.; Bayanov, B.; Belchenko, Yu.; Belov, V.; Davydenko, V.; Donin, A.; Dranichnikov, A.; Ivanov, A.; Kandaurov, I; Kraynov, G.; Krivenko, A.; Kudryavtsev, A.; Kursanov, N.; Savkin, V.; Shirokov, V.; Sorokin, I.; Taskaev, S.; Tiunov, M.

2004-01-01

Full text: The Budker Institute of Nuclear Physics (Novosibirsk) and the Institute of Physics and Power Engineering (Obninsk) have proposed an accelerator based neutron source for neutron capture and fast neutron therapy for hospital. Innovative approach is based upon vacuum insulation tandem accelerator (VITA) and near threshold 7 Li(p,n) 7 Be neutron generation. Pilot accelerator based neutron source for neutron capture therapy is under construction now at the Budker Institute of Nuclear Physics, Novosibirsk, Russia. In the present report, the pilot facility design is presented and discussed. Design features of facility components are discussed. Results of experiments and simulations are presented. Complete experimental tests are planned by the end of the year 2005

Computational complexity in multidimensional neutron transport theory calculations. Progress report, September 1, 1975--August 31, 1976

International Nuclear Information System (INIS)

Bareiss, E.H.

1976-05-01

The objectives of the work are to develop mathematically and computationally founded for the design of highly efficient and reliable multidimensional neutron transport codes to solve a variety of neutron migration and radiation problems, and to analyze existing and new methods for performance. As new analytical insights are gained, new numerical methods are developed and tested. Significant results obtained include implementation of the integer-preserving Gaussian elimination method (two-step method) in a CDC 6400 computer code, modes analysis for one-dimensional transport solutions, and a new method for solving the 1-T transport equation. Some of the work dealt with the interface and corner problem in diffusion theory

Progress in radioactive graphite waste management

International Nuclear Information System (INIS)

2010-07-01

Radioactive graphite constitutes a major waste stream which arises during the decommissioning of certain types of nuclear installations. Worldwide, a total of around 250 000 tonnes of radioactive graphite, comprising graphite moderators and reflectors, will require management solutions in the coming years. 14 C is the radionuclide of greatest concern in nuclear graphite; it arises principally through the interaction of reactor neutrons with nitrogen, which is present in graphite as an impurity or in the reactor coolant or cover gas. 3 H is created by the reactions of neutrons with 6 Li impurities in graphite as well as in fission of the fuel. 36 Cl is generated in the neutron activation of chlorine impurities in graphite. Problems in the radioactive waste management of graphite arise mainly because of the large volumes requiring disposal, the long half-lives of the main radionuclides involved and the specific properties of graphite - such as stored Wigner energy, graphite dust explosibility and the potential for radioactive gases to be released. Various options for the management of radioactive graphite have been studied but a generally accepted approach for its conditioning and disposal does not yet exist. Different solutions may be appropriate in different cases. In most of the countries with radioactive graphite to manage, little progress has been made to date in respect of the disposal of this material. Only in France has there been specific thinking about a dedicated graphite waste-disposal facility (within ANDRA): other major producers of graphite waste (UK and the countries of the former Soviet Union) are either thinking in terms of repository disposal or have no developed plans. A conference entitled 'Solutions for Graphite Waste: a Contribution to the Accelerated Decommissioning of Graphite Moderated Nuclear Reactors' was held at the University of Manchester 21-23 March 2007 in order to stimulate progress in radioactive graphite waste management

Design of hyper-thermal neutron irradiation fields for neutron capture therapy in KUR-heavy water neutron irradiation facility. Mounting of hyper-thermal neutron converter in therapeutic collimator

International Nuclear Information System (INIS)

Sakurai, Y.; Kobayashi, T.

2001-01-01

Neutron capture therapy (NCP) using thermal neutron needs to improve of depth dose distribution in a living body. Epi-thermal neutron following moderation of fast neutron is usually used for improving of the depth dose distribution. The moderation method of fast neutron, however, gets mixed some of high energy neutron which give some of serious effects to a living body, and involves the difficulty for collimation of thermal neutron to the diseased part. Hyper-thermal neutrons, which are in an energy range of 0.1-3 eV at high temperature side of thermal neutron, are under consideration for application to the NCP. The hyper-thermal neutrons can be produced by up-scattering of thermal neutron in a high temperature material. Fast neutron components in collimator for the NCP reduce on application of the up-scattering method. Graphite at high temperature (>1000k) is used as a hyper-thermal neutron converter. The hyper-thermal neutron converter is planted to mount on therapeutic collimator which is located at the nearest side of patient for the NCP. Total neutron flux, ratio of hyper-thermal neutron to total neutron, and ratio of gamma-ray dose to neutron flux are calculated as a function of thickness of the graphite converter using monte carlo code MCNP-V4B. (M. Suetake)

Neutronics and radiation field studies for the RIA fragmentation target area

Energy Technology Data Exchange (ETDEWEB)

Reyes, Susana [Lawrence Livermore National Laboratory, P.O. Box 808, L-446, Livermore, CA 94550 (United States)]. E-mail: reyes20@llnl.gov; Boles, Jason L. [Lawrence Livermore National Laboratory, P.O. Box 808, L-446, Livermore, CA 94550 (United States); Ahle, Larry E. [Lawrence Livermore National Laboratory, P.O. Box 808, L-446, Livermore, CA 94550 (United States); Stein, Werner [Lawrence Livermore National Laboratory, P.O. Box 808, L-446, Livermore, CA 94550 (United States)

2006-06-23

Neutronics simulations and activation evaluations are currently in progress as part of the pre-conceptual research and development effort for the Rare Isotope Accelerator (RIA). The RIA project involves generating heavy element ion beams with powers up to 400 kw for use in a fragmentation target line to produce selected ion beams for physics research experiments. Designing a fragmentation beam dump for RIA is one of the most critical challenges for such a facility. Here, we present the results from neutronics and radiation field assessments for various beam dump concepts that can meet requirements for the RIA fragmentation line. Preliminary results from heavy ion transport including radiation damage evaluations for the RIA fragmentation beam dump are also presented. Initial neutronics and activation studies will be incorporated with other target area considerations to identify important challenges and explore possible solutions.

Neutronics and radiation field studies for the RIA fragmentation target area

Science.gov (United States)

Reyes, Susana; Boles, Jason L.; Ahle, Larry E.; Stein, Werner

2006-06-01

Neutronics simulations and activation evaluations are currently in progress as part of the pre-conceptual research and development effort for the Rare Isotope Accelerator (RIA). The RIA project involves generating heavy element ion beams with powers up to 400 kW for use in a fragmentation target line to produce selected ion beams for physics research experiments. Designing a fragmentation beam dump for RIA is one of the most critical challenges for such a facility. Here, we present the results from neutronics and radiation field assessments for various beam dump concepts that can meet requirements for the RIA fragmentation line. Preliminary results from heavy ion transport including radiation damage evaluations for the RIA fragmentation beam dump are also presented. Initial neutronics and activation studies will be incorporated with other target area considerations to identify important challenges and explore possible solutions.

The secondary neutron sources for generation of particular neutron fluxes

International Nuclear Information System (INIS)

Tracz, G.

2007-07-01

The foregoing paper presents the doctor's thesis entitled '' The secondary neutron sources for generation of particular neutron fluxes ''. Two secondary neutron sources have been designed, which exploit already existing primary sources emitting neutrons of energies different from the desired ones. The first source is devoted to boron-neutron capture therapy (BNCT). The research reactor MARIA at the Institute of Atomic Energy in Swierk (Poland) is the primary source of the reactor thermal neutrons, while the secondary source should supply epithermal neutrons. The other secondary source is the pulsed source of thermal neutrons that uses fast 14 MeV neutrons from a pulsed generator at the Institute of Nuclear Physics PAN in Krakow (Poland). The physical problems to be solved in the two mentioned cases are different. Namely, in order to devise the BNCT source the initial energy of particles ought to be increased, whilst in the other case the fast neutrons have to be moderated. Slowing down of neutrons is relatively easy since these particles lose energy when they scatter in media; the most effective moderators are the materials which contain light elements (mostly hydrogen). In order to increase the energy of neutrons from thermal to epithermal (the BNCT case) the so-called neutron converter should be exploited. It contains a fissile material, 235 U. The thermal neutrons from the reactor cause fission of uranium and fast neutrons are emitted from the converter. Then fissile neutrons of energy of a few MeV are slowed down to the required epithermal energy range. The design of both secondary sources have been conducted by means of Monte Carlo simulations, which have been carried out using the MCNP code. In the case of the secondary pulsed thermal neutron source, some of the calculated results have been verified experimentally. (author)

Neutrons and model membranes

Science.gov (United States)

Fragneto, G.

2012-11-01

Current research in membrane protein biophysics highlights the emerging role of lipids in shaping membrane protein function. Cells and organisms have developed sophisticated mechanisms for controlling the lipid composition and many diseases are related to the failure of these mechanisms. One of the recent advances in the field is the discovery of the existence of coexisting micro-domains within a single membrane, important for regulating some signaling pathways. Many important properties of these domains remain poorly characterized. The characterization and analysis of bio-interfaces represent a challenge. Performing measurements on these few nanometer thick, soft, visco-elastic and dynamic systems is close to the limits of the available tools and methods. Neutron scattering techniques including small angle scattering, diffraction, reflectometry as well as inelastic methods are rapidly developing for these studies and are attracting an increasing number of biologists and biophysicists at large facilities. This manuscript will review some recent progress in the field and provide perspectives for future developments. It aims at highlighting neutron reflectometry as a versatile method to tackle questions dealing with the understanding and function of biomembranes and their components. The other important scattering methods are only briefly introduced.

Approaches for the generation of a covariance matrix for the Cf-252 fission-neutron spectrum

International Nuclear Information System (INIS)

Mannhart, W.

1983-01-01

After a brief retrospective glance is cast at the situation, the evaluation of the Cf-252 neutron spectrum with a complete covariance matrix based on the results of integral experiments is proposed. The different steps already taken in such an evaluation and work in progress are reviewed. It is shown that special attention should be given to the normalization of the neutron spectrum which must be reflected in the covariance matrix. The result of the least-squares adjustment procedure applied can easily be combined with the results of direct spectrum measurements and should be regarded as the first step in a new evaluation of the Cf-252 fission-neutron spectrum. (author)

Calculations to support JET neutron yield calibration: Modelling of neutron emission from a compact DT neutron generator

Science.gov (United States)

Čufar, Aljaž; Batistoni, Paola; Conroy, Sean; Ghani, Zamir; Lengar, Igor; Milocco, Alberto; Packer, Lee; Pillon, Mario; Popovichev, Sergey; Snoj, Luka; JET Contributors

2017-03-01

At the Joint European Torus (JET) the ex-vessel fission chambers and in-vessel activation detectors are used as the neutron production rate and neutron yield monitors respectively. In order to ensure that these detectors produce accurate measurements they need to be experimentally calibrated. A new calibration of neutron detectors to 14 MeV neutrons, resulting from deuterium-tritium (DT) plasmas, is planned at JET using a compact accelerator based neutron generator (NG) in which a D/T beam impinges on a solid target containing T/D, producing neutrons by DT fusion reactions. This paper presents the analysis that was performed to model the neutron source characteristics in terms of energy spectrum, angle-energy distribution and the effect of the neutron generator geometry. Different codes capable of simulating the accelerator based DT neutron sources are compared and sensitivities to uncertainties in the generator's internal structure analysed. The analysis was performed to support preparation to the experimental measurements performed to characterize the NG as a calibration source. Further extensive neutronics analyses, performed with this model of the NG, will be needed to support the neutron calibration experiments and take into account various differences between the calibration experiment and experiments using the plasma as a source of neutrons.

Calculations to support JET neutron yield calibration: Modelling of neutron emission from a compact DT neutron generator

Energy Technology Data Exchange (ETDEWEB)

Čufar, Aljaž, E-mail: aljaz.cufar@ijs.si [Reactor Physics Department, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Batistoni, Paola [ENEA, Department of Fusion and Nuclear Safety Technology, I-00044 Frascati, Rome (Italy); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Conroy, Sean [Uppsala University, Department of Physics and Astronomy, PO Box 516, SE-75120 Uppsala (Sweden); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Ghani, Zamir [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Lengar, Igor [Reactor Physics Department, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Milocco, Alberto; Packer, Lee [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Pillon, Mario [ENEA, Department of Fusion and Nuclear Safety Technology, I-00044 Frascati, Rome (Italy); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Popovichev, Sergey [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Snoj, Luka [Reactor Physics Department, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

2017-03-01

At the Joint European Torus (JET) the ex-vessel fission chambers and in-vessel activation detectors are used as the neutron production rate and neutron yield monitors respectively. In order to ensure that these detectors produce accurate measurements they need to be experimentally calibrated. A new calibration of neutron detectors to 14 MeV neutrons, resulting from deuterium–tritium (DT) plasmas, is planned at JET using a compact accelerator based neutron generator (NG) in which a D/T beam impinges on a solid target containing T/D, producing neutrons by DT fusion reactions. This paper presents the analysis that was performed to model the neutron source characteristics in terms of energy spectrum, angle–energy distribution and the effect of the neutron generator geometry. Different codes capable of simulating the accelerator based DT neutron sources are compared and sensitivities to uncertainties in the generator's internal structure analysed. The analysis was performed to support preparation to the experimental measurements performed to characterize the NG as a calibration source. Further extensive neutronics analyses, performed with this model of the NG, will be needed to support the neutron calibration experiments and take into account various differences between the calibration experiment and experiments using the plasma as a source of neutrons.

Paul Scherrer Institute Scientific Report 2000. Volume III: Condensed Matter Research with Neutrons

Energy Technology Data Exchange (ETDEWEB)

Schefer, Juerg; Castellazzi, Denise; Shea-Braun, Margit [eds.

2001-07-01

This year started with a highlight for the Swiss Spallation Neutron Source SINQ located at PSI: The thermal neutron flux exceeded the value of 10{sup 14} n cm{sup -2} s{sup 1} which may be considered as the critical limit for an advanced medium-flux neutron source. The excellent performance attracted a large number of external users to participate at the neutron scattering programme. The major part of this annual report gives an overview on the scientific activities of the staff members of the Laboratory of Neutron Scattering (jointly operated with the Swiss Federal Institute of Technology, ETH Zurich). The research topics covered diverse areas such as strongly correlated electron systems including high-temperature superconductors, low-dimensional and quantum magnetism, materials research on soft and hard matter including multilayers. Progress in 2000 in these topical areas as well as the activities of the Condensed Matter Theory Group, and the Group for Low Temperature Facilities, is described in this report. A list of scientific publications in 2000 is also provided.

Paul Scherrer Institute Scientific Report 2000. Volume III: Condensed Matter Research with Neutrons

International Nuclear Information System (INIS)

Schefer, Juerg; Castellazzi, Denise; Shea-Braun, Margit

2001-01-01

This year started with a highlight for the Swiss Spallation Neutron Source SINQ located at PSI: The thermal neutron flux exceeded the value of 10 14 n cm -2 s 1 which may be considered as the critical limit for an advanced medium-flux neutron source. The excellent performance attracted a large number of external users to participate at the neutron scattering programme. The major part of this annual report gives an overview on the scientific activities of the staff members of the Laboratory of Neutron Scattering (jointly operated with the Swiss Federal Institute of Technology, ETH Zurich). The research topics covered diverse areas such as strongly correlated electron systems including high-temperature superconductors, low-dimensional and quantum magnetism, materials research on soft and hard matter including multilayers. Progress in 2000 in these topical areas as well as the activities of the Condensed Matter Theory Group, and the Group for Low Temperature Facilities, is described in this report. A list of scientific publications in 2000 is also provided

Study of neutron fields around an intense neutron generator.

Science.gov (United States)

Kicka, L; Machrafi, R; Miller, A

2017-12-01

Neutron fields in the vicinity of the newly built neutron facility, at the University of Ontario Institute of Technology (UOIT), have been investigated in a series of Monte Carlo simulations and measurements. The facility hosts a P-385 neutron generator based on a deuterium-deuterium fusion reaction. The neutron fluence at different locations around the neutron generator facility has been simulated using MCNPX 2.7E Monte Carlo particle transport program. To characterize neutron fields, three neutron sources were modeled with distributions corresponding to different incident deuteron energies of 90kV, 110kV, and 130kV. Measurements have been carried out to determine the dose rate at locations adjacent to the generator using bubble detectors (BDs). The neutron intensity was evaluated and the total dose rates corresponding to different applied acceleration potentials were estimated at various locations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Miscellaneous neutron techniques

International Nuclear Information System (INIS)

Iddings, F.A.

1976-01-01

Attention is brought to the less often uses of neutrons in the areas of neutron radiography, well logging, and neutron gaging. Emphasis on neutron radiography points toward the isotopic sensitivity of the method versus the classical bulk applications. Also recognized is the ability of neutron radiography to produce image changes that correspond to thickness and density changes obtained in photon radiography. Similarly, neutron gaging applications center on the measurement of radiography. Similarly, neutron gaging applications center on the measurement of water, oil, or plastics in industrial samples. Well logging extends the neutron gaging to encompass many neutron properties and reactions besides thermalization and capture. Neutron gaging also gives information on organic structure and concentrations of a variety of elements or specific compounds in selected matrices

Discovery of the neutron (to the fiftieth anniversary of neutron discovery)

International Nuclear Information System (INIS)

Pasechnik, M.V.

1984-01-01

Development of neutron physics in the USSR for the recent 50 years from the moment of neutron discovery is considered. History of neutron discovery is presented in brief. Neutron properties and fundamental problems of physics: electric dipole neutron moment, neutron β-decay, neutron interaction with nuclei and potential of nucleon interaction not conserving spatial parity are discussed. Main aspects of neutron physics application in power engineering, nuclear technology and other branches of science and technique are set forth

Neutron rich matter, neutron stars, and their crusts

International Nuclear Information System (INIS)

Horowitz, C J

2011-01-01

Neutron rich matter is at the heart of many fundamental questions in Nuclear Physics and Astrophysics. What are the high density phases of QCD? Where did the chemical elements come from? What is the structure of many compact and energetic objects in the heavens, and what determines their electromagnetic, neutrino, and gravitational-wave radiations? Moreover, neutron rich matter is being studied with an extraordinary variety of new tools such as Facility for Rare Isotope Beams (FRIB) and the Laser Interferometer Gravitational Wave Observatory (LIGO). We describe the Lead Radius Experiment (PREX) that is using parity violation to measure the neutron radius in 208Pb. This has important implications for neutron stars and their crusts. Using large scale molecular dynamics, we model the formation of solids in both white dwarfs and neutron stars. We find neutron star crust to be the strongest material known, some 10 billion times stronger than steel. It can support mountains on rotating neutron stars large enough to generate detectable gravitational waves. Finally, we describe a new equation of state for supernova and neutron star merger simulations based on the Virial expansion at low densities, and large scale relativistic mean field calculations.

Neutron resonance radiography: Report of a workshop, Los Alamos, NM: July 27-29, 1987

International Nuclear Information System (INIS)

1988-07-01

Neutron resonance radiography is a new technique with great potential for non-destructive analysis and testing. This technique has been under research and development in a number of major research laboratories for some time. Unlike thermal neutron radiography, which is primarily oriented towards imaging hydrogen and a number of other highly neutron-absorptive materials without necessarily distinguishing between them, neutron resonance radiography has the capability of uniquely identifying many kinds of chemical elements and their individual isotopes. It also has the potential for temperature imaging in materials containing heavy elements and for certain dynamic features such as stroboscopic imaging. Although neutron resonance radiography has not yet been taken up in a systematic way for technological applications, significant development of ideas and instrumentation at the research level has blossomed. There have also been major developments in the availability of powerful pulsed-neutron sources. In light of these developments, the Los Alamos Neutron Scattering Center sponsored a workshop with the general aims of reviewing scientific and technical progress, discussing and highlighting future developments, and stimulating interest in technological exploitation of the methods. In addition to the techniques and instrumentation required for the field, the applications of neutron resonance radiography in some of the following industrial and manufacturing areas were discussed: nuclear fuel assay; nuclear safeguards in general; aerospace development (aeroengine blade temperature, stroboscopic techniques); diagnostics; non-nuclear industry (especially metallurgy); temperature imaging; use of mobile pulsed-neutron sources; and practical use of major pulsed-neutron facilities

Starquakes, Heating Anomalies, and Nuclear Reactions in the Neutron Star Crust

Science.gov (United States)

Deibel, Alex Thomas

When the most massive stars perish, their cores may remain intact in the form of extremely dense and compact stars. These stellar remnants, called neutron stars, are on the cusp of becoming black holes and reach mass densities greater than an atomic nucleus in their centers. Although the interiors of neutron stars were difficult to investigate at the time of their discovery, the advent of modern space-based telescopes (e.g., Chandra X-ray Observatory) has pushed our understanding of the neutron star interior into exciting new realms. It has been shown that the neutron star interior spans an enormous range of densities and contains many phases of matter, and further theoretical progress must rely on numerical calculations of neutron star phenomena built with detailed nuclear physics input. To further investigate the properties of the neutron star interior, this dissertation constructs numerical models of neutron stars, applies models to various observations of neutron star high-energy phenomena, and draws new conclusions about the neutron star interior from these analyses. In particular, we model the neutron star's outermost ? 1 km that encompasses the neutron star's envelope, ocean, and crust. The model must implement detailed nuclear physics to properly simulate the hydrostatic and thermal structure of the neutron star. We then apply our model to phenomena that occur in these layers, such as: thermonuclear bursts in the envelope, g-modes in the ocean, torsional oscillations of the crust, and crust cooling of neutron star transients. A comparison of models to observations provides new insights on the properties of dense matter that are often difficult to probe through terrestrial experiments. For example, models of the quiescent cooling of neutron stars, such as the accreting transient MAXI J0556-332, at late times into quiescence probe the thermal transport properties of the deep neutron star crust. This modeling provides independent data from astronomical

KURRI progress report 2004. April 2004 - March 2005

International Nuclear Information System (INIS)

2005-01-01

The fiscal year 2004 was the 40-th anniversary of Kyoto University research Reactor (KUR) and also the 30-th anniversary of Kyoto University Critical Assembly (KUCA). The KUR and KUCA have been operated for 1,316 and 732 hours, respectively. Kyoto University Research Reactor Institute (KURRI) accepted 5,186 man-day researchers including students in total for their experiments in accordance with the joint use programs among Japanese universities and public research organizations, and for scientific meetings held at KURRI. Note here that, since the application of boron neutron capture therapy (BNCT) was expanded to the head and neck cancers in addition to the brain tumors and skin cancers, the number of patients treated with the BNCT was greatly increasing year by year. Number of clinical irradiations were 11 in FY2002, 36 in FY2003, and 54 in FY2004. The results of these activities are reported in this progress report. The total 153 research issues are categorized to the 10 topics as follows; (1) Slow Neutron Physics and Neutron Scattering includes the 8 issues as general researches. (2) Nuclear Physics and Nuclear Data includes the 15 issues for the project research and the 2 issues as general researches. (3) Reactor Physics and Reactor Engineering includes the 6 issues as general researches. (4) Material Science and Radiation Effects includes the 21 issues for the project research and the 21 issues as general researches. (5) Geochemistry and Environmental Science includes the 16 issues as general researches. (6) Life Science and Medical Science includes the 5 issues for the project research and the 14 issues as general researches. (7) Neutron Capture Therapy includes the 19 issues as general researches. (8) Neutron Radiography and Radiation Application includes the 9 issues for the project research and the 3 issues as general researches. (9) TRU and Nuclear Chemistry includes the 11 issues for the project research. (10) Health Physics and Waste Management includes

European Fusion Programme. ITER task T23: Beryllium characterisation. Progress report. Tensile tests on neutron irradiated and reference beryllium

International Nuclear Information System (INIS)

Moons, F.

1996-02-01

As part of the European Technology Fusion Programme, the irradiation embrittlement characteristics of the more ductile and isotopic grades of beryllium manufactured by Brush Wellman has been investigated using modern powder production and consolidation techniques . This study was initiated in support of the development and evaluation of beryllium as a neutron multiplier for the solid breeder blanket design concepts proposed for a DEMO fusion power reactor. Four different species of beryllium: S-200 F (vacuum hot pressed, 1.2 wt% BeO), S-200FH (hot isostatic pressed, 0.9 wt% BeO), S-65 (vacuum hot pressed, 0.6 wt% BeO), S-65H (hot isostatic pressed, 0.5 wt% BeO) have been compared. Three batches of the beryllium have been investigated, a neutron batch, a thermal control batch and a reference batch. Neutron irradiation has been performed at temperatures between 175 and 605 degrees Celsius up to a neutron fluence of 2.1 10 25 n.m -2 (E> 1 MeV) or 750 appm He. The results of the tensile tests are summarized

Communication of nuclear data progress: No.9 (1993)

International Nuclear Information System (INIS)

1993-06-01

The is the ninth issue of > (CNDP), in which the nuclear data progress in China during the passed year is carried. It includes optical model parameters for both small angles and larger angles elastic scattering, n-T phase shift analyses, forbidden angular region of secondary particle emission, introduction to codes CMUP2 and CFUP1, diffusion process of nuclear fission, techniques used for charged particle evaluation at CNDC, evaluation of neutron nuclear data for 7 Li and revision on recommended data of 238 U for CENDL-2, Chinese Evaluated Nuclear Parameter Library (CENPL) (II) and computer program library at CNDC, covariance data evaluation for experimental data and several examples of least squares combination for derived data, and calculation of thermal neutron scattering law for anisotropic microcrystals etc

Ultra Low Level Environmental Neutron Measurements Using Superheated Droplet Detectors

Energy Technology Data Exchange (ETDEWEB)

Fernandes, A.C. [Centro de Ciencias e Tecnologias Nucleares, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Estrada Nacional 10 - km 139.7, 2695-066 Bobadela LRS (Portugal); Centro de Fisica Nuclear, Universidade de Lisboa. Av. Prof. Gama Pinto, 2, 1649- 003 Lisboa (Portugal); Felizardo, M.; Girard, T.A.; Kling, A.; Ramos, A.R. [Centro de Fisica Nuclear, Universidade de Lisboa. Av. Prof. Gama Pinto, 2, 1649- 003 Lisboa (Portugal); Marques, J.G.; Prudencio, M.I.; Marques, R.; Carvalho, F.P. [Centro de Ciencias e Tecnologias Nucleares, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Estrada Nacional 10 - km 139.7, 2695-066 Bobadela LRS (Portugal)

2015-07-01

signal contribution (98%) originates from radio-impurities in the detector container, alternative materials will be employed in future devices. Latest results regarding the improvement of the detector characterization accuracy towards its application in environmental neutron detection are in progress and will be described. (authors)

Neutron Beam Filters

International Nuclear Information System (INIS)

Adib, M.

2011-01-01

The purpose of filters is to transmit neutrons with selected energy, while remove unwanted ones from the incident neutron beam. This reduces the background, and the number of spurious. The types of commonly used now-a-day neutron filters and their properties are discussed in the present work. There are three major types of neutron filters. The first type is filter of selective thermal neutron. It transmits the main reflected neutrons from a crystal monochromate, while reject the higher order contaminations accompanying the main one. Beams coming from the moderator always contain unwanted radiation like fast neutrons and gamma-rays which contribute to experimental background and to the biological hazard potential. Such filter type is called filter of whole thermal neutron spectrum. The third filter type is it transmits neutrons with energies in the resonance energy range (En . 1 KeV). The main idea of such neutron filter technique is the use of large quantities of a certain material which have the deep interference minima in its total neutron cross-section. By transmitting reactor neutrons through bulk layer of such material, one can obtain the quasimonochromatic neutron lines instead of white reactor spectrum.

Advanced Neutron Source (ANS) Project

International Nuclear Information System (INIS)

Campbell, J.H.; Thompson, P.B.

1994-01-01

This report covers the progress made in 1993 in the following sections: (1) project management; (2) research and development; (3) design and (4) safety. The section on research and development covers the following: (1) reactor core development; (2) fuel development; (3) corrosion loop tests and analysis; (4) thermal-hydraulic loop tests; (5) reactor control and shutdown concepts; (6) critical and subcritical experiments; (7) material data, structure tests, and analysis; (8) cold source development; (9) beam tube, guide, and instrument development; (10) neutron transport and shielding; (11) I and C research and development; and (12) facility concepts

Neutron stochastic transport theory with delayed neutrons

International Nuclear Information System (INIS)

Munoz-Cobo, J.L.; Verdu, G.

1987-01-01

From the stochastic transport theory with delayed neutrons, the Boltzmann transport equation with delayed neutrons for the average flux emerges in a natural way without recourse to any approximation. From this theory a general expression is obtained for the Feynman Y-function when delayed neutrons are included. The single mode approximation for the particular case of a subcritical assembly is developed, and it is shown that Y-function reduces to the familiar expression quoted in many books, when delayed neutrons are not considered, and spatial and source effects are not included. (author)

Ultracold neutron source at the PULSTAR reactor: Engineering design and cryogenic testing

Energy Technology Data Exchange (ETDEWEB)

Korobkina, E., E-mail: ekorobk@ncsu.edu [Department of Nuclear Engineering, North Carolina State University, 2500 Stinson Drive, Box 7909, Raleigh, NC 27695 (United States); Medlin, G. [Department of Physics, North Carolina State University, 2401 Stinson Drive, Box 8202, Raleigh, NC 27695 (United States); Triangle Universities Nuclear Laboratory, 116 Science Drive, Box 90308, Durham, NC 27708 (United States); Wehring, B.; Hawari, A.I. [Department of Nuclear Engineering, North Carolina State University, 2500 Stinson Drive, Box 7909, Raleigh, NC 27695 (United States); Huffman, P.R.; Young, A.R. [Department of Physics, North Carolina State University, 2401 Stinson Drive, Box 8202, Raleigh, NC 27695 (United States); Triangle Universities Nuclear Laboratory, 116 Science Drive, Box 90308, Durham, NC 27708 (United States); Beaumont, B. [Department of Physics, North Carolina State University, 2401 Stinson Drive, Box 8202, Raleigh, NC 27695 (United States); Palmquist, G. [Department of Physics, North Carolina State University, 2401 Stinson Drive, Box 8202, Raleigh, NC 27695 (United States); Triangle Universities Nuclear Laboratory, 116 Science Drive, Box 90308, Durham, NC 27708 (United States)

2014-12-11

Construction is completed and commissioning is in progress for an ultracold neutron (UCN) source at the PULSTAR reactor on the campus of North Carolina State University. The source utilizes two stages of neutron moderation, one in heavy water at room temperature and the other in solid methane at ∼40K, followed by a converter stage, solid deuterium at 5 K, that allows a single down scattering of cold neutrons to provide UCN. The UCN source rolls into the thermal column enclosure of the PULSTAR reactor, where neutrons will be delivered from a bare face of the reactor core by streaming through a graphite-lined assembly. The source infrastructure, i.e., graphite-lined assembly, heavy-water system, gas handling system, and helium liquefier cooling system, has been tested and all systems operate as predicted. The research program being considered for the PULSTAR UCN source includes the physics of UCN production, fundamental particle physics, and material surface studies of nanolayers containing hydrogen. In the present paper we report details of the engineering and cryogenic design of the facility as well as results of critical commissioning tests without neutrons.

Progress in measurement of (n,x) cross sections at HST in 1995

Energy Technology Data Exchange (ETDEWEB)

Bangjiao, Ye; Zhongmin, Wang; Yangmei, Fan; Rongdian, Han; Xiaoqi, Yu; Huaijiang, Du [Department of Modern Physics, Univ. of Sci. and Tech. of China (China)

1996-06-01

The measurement of energy spectrum and angular distributions of protons emission from reaction induced by 14.6 MeV neutron bombarding stainless steel has been performed at Univ. of Sci. and Tech. of China, Hefei (HST) by using multitelescope system. 14.6 MeV neutrons were produced by 150 KeV Cockcroft-Walton accelerator. The 1Cr18Ni9Ti (type 321) stainless steel target with 0.8 mm thick and 40 mm height was used. The progress on measurement of {sup nat}Ni(n,x{alpha}) reaction cross sections are introduced. (2 figs.).

Fundamental of neutron radiography and the present of neutron radiography in Japan

International Nuclear Information System (INIS)

Sekita, Junichiro

1988-01-01

Neutron radiography refers to the application of transmitted neutrons to analysis. In general, thermal neutron is used for neutron radiography. Thermal neutron is easily absorbed by light atoms, including hydrogen, boron and lithium, while it is not easily absorbed by such heavy atoms as tungsten, lead and uranium, permitting detection of impurities in heavy metals. Other neutrons than thermal neutron can also be applied. Cold neutron is produced from fast neutron using a moderator to reduce its energy down to below that of thermal neutron. Cold neutron is usefull for analysis of thick material. Epithermal neutron can induce resonance characteristic of each substance. With a relatively small reaction area, fast neutron permits observation of thick samples. Being electrically neutral, neutrons are difficult to detect by direct means. Thus a substance that releases charged particles is put in the path of neutrons for indirect measurement. X-ray film combined with converter screen for conversion of neutrons to charge particles is placed behind the sample. Photographing is carried out by a procedure similar to X-ray photography. Major institues and laboratories in Japan provided with neutron radiography facilities are listed. (Nogami, K.)

Recent performance of the Intense Pulsed Neutron Source accelerator system

International Nuclear Information System (INIS)

Potts, C.; Brumwell, F.; Rauchas, A.; Stipp, V.; Volk, G.; Donley, L.

1987-03-01

The Intense Pulsed Neutron Source (IPNS) accelerator system has now been in operation as part of a national user program for over five years. During that period steady progress has been made in both beam intensity and reliability. Almost 1.8 billion pulses totaling 4 x 10 21 protons have now been delivered to the spallation neutron target. Recent weekly average currents have reached 15 μA (3.2 x 10 12 protons per pulse, 30 pulses per second) and short-term peaks of almost 17 μA have been reached. In fact, the average current for the last two years is up 31% over the average for the first three years of operation

Review of Non-Neutron and Neutron Nuclear Data, 2004

International Nuclear Information System (INIS)

Holden, Norman E.

2005-01-01

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

The first IEC fusion industrial neutron generator and developments

Science.gov (United States)

Sved, John

1999-06-01

Inertial Electrostatic Confinement fusion grade plasma containment has been sporadically researched since the early 1960's. In the 1990's the work of G. H. Miley and his team at the University of Illinios, Fusion Studies Laboratory, Champaign-Urbana has stimulated a collaboration with industry. The development and test program for the first industrial IEC neutron generator has progressed to the point where an endurance test is under way to demonstrate at least 10,000 hours of operational life of the sealed chamber device without servicing. The market entry goals of steady 107 D-D n/s CW output with an air-cooled system have been achieved. DASA has invested in the development of the industrial product and the continuing basic research at the UI-FSL. The complete DASA FusionStar IEC-PS1 point source neutron generator set is described with emphasis on the interfaces to user NAA systems. The next product developments are pulsed neutron operations and higher fusion reaction rates of up to 1010 by means of affordable add-ons to the basic IEC-PS system. The production engineering experience gained will next be applied to a more challenging line source variant of the IEC. Beyond neutron and proton sources, several other IEC applications are being developed.

Measurement of thermal neutron distribution of flux in the fuel element cluster - Progress report

International Nuclear Information System (INIS)

Krcevinac, S.B.; Takac, S.M.

1966-12-01

Relative distribution of thermal neutron flux in the fuel element cluster (19 UO 2 rods with Zr-II cladding, D 2 O moderator and coolant) was measured by newly developed cell perturbation method. The obtained values of mean density ratios are compared to the results obtained by TER-I code using Amouyal - Benoist model [sr

Inelastic neutron scattering of H{sub 2} adsorbed in HKUST-1

Energy Technology Data Exchange (ETDEWEB)

Liu, Y. [Department of Materials and Engineering, University of Maryland, College Park, MD 20742 (United States); NIST Center for Neutron Research, 100 Bureau Drive, Gaithersburg, MD 20899-8562 (United States); Brown, C.M. [NIST Center for Neutron Research, 100 Bureau Drive, Gaithersburg, MD 20899-8562 (United States); Indiana University Cyclotron Facility, Indiana University, 2401 Milo B. Sampson Lane, Bloomington, IN 47408 (United States)], E-mail: craig.brown@nist.gov; Neumann, D.A. [NIST Center for Neutron Research, 100 Bureau Drive, Gaithersburg, MD 20899-8562 (United States); Peterson, V.K.; Kepert, C.J. [School of Chemistry, University of Sydney, NSW 2006 (Australia)

2007-10-31

A series of inelastic neutron scattering (INS) investigations of hydrogen adsorbed in activated HKUST-1 (Cu{sub 3}(1,3,5-benzenetricarboxylate){sub 2}) result in INS spectra with rich features, even at very low loading (<1.0 H{sub 2}:Cu). The distinct inelastic features in the spectra show that there are three binding sites that are progressively populated when the H{sub 2} loading is less than 2.0 H{sub 2}:Cu, which is consistent with the result obtained from previous neutron powder diffraction experiments. The temperature dependence of the INS spectra reveals the relative binding enthalpies for H{sub 2} at each site.

Observation of Neutron Skyshine from an Accelerator Based Neutron Source

Energy Technology Data Exchange (ETDEWEB)

Franklyn, C. B. [Radiation Science Department, Necsa, PO Box 582, Pretoria 0001 (South Africa)

2011-12-13

A key feature of neutron based interrogation systems is the need for adequate provision of shielding around the facility. Accelerator facilities adapted for fast neutron generation are not necessarily suitably equipped to ensure complete containment of the vast quantity of neutrons generated, typically >10{sup 11} n{center_dot}s{sup -1}. Simulating the neutron leakage from a facility is not a simple exercise since the energy and directional distribution can only be approximated. Although adequate horizontal, planar shielding provision is made for a neutron generator facility, it is sometimes the case that vertical shielding is minimized, due to structural and economic constraints. It is further justified by assuming the atmosphere above a facility functions as an adequate radiation shield. It has become apparent that multiple neutron scattering within the atmosphere can result in a measurable dose of neutrons reaching ground level some distance from a facility, an effect commonly known as skyshine. This paper describes a neutron detection system developed to monitor neutrons detected several hundred metres from a neutron source due to the effect of skyshine.

Progress in the development of phase-sensitive neutron reflectometry methods

International Nuclear Information System (INIS)

Majkrzak, C.F.; Berk, N.F.; Kienzle, P.; Perez-Salas, U.

2009-01-01

It has been a number of years since phase-sensitive specular neutron reflectometry (PSNR) methods employing reference layers were first introduced to help remove the ambiguity inherent in the reconstruction of scattering length density (SLD) depth profiles (Majkrzak, C. F.; Berk, N. F. Physica B 2003, 336, 27) from specular reflectivity measurements. Although a number of scientific applications of PSNR techniques have now been successfully realized (Majkrzak, C. F.; Berk, N. F.; Perez-Salas, U. A. Langmuir 2003, 19, 7796 and references therein), in certain cases practical difficulties remain. In this article, we describe possible solutions to two specific problems: (1) the need for explicit, detailed knowledge of the SLD profile of a given reference layer of finite thickness; and (2) for a reference layer of finite thickness in which only two density variations are possible, how to identify which of two mathematical solutions corresponds to the true physical structure.

Progress in the development of phase-sensitive neutron reflectometry methods.

Energy Technology Data Exchange (ETDEWEB)

Majkrzak, C. F.; Berk, N. F.; Kienzle, P.; Perez-Salas, U. (Materials Science Division); (NIST Center for Neutron Research)

2009-01-01

It has been a number of years since phase-sensitive specular neutron reflectometry (PSNR) methods employing reference layers were first introduced to help remove the ambiguity inherent in the reconstruction of scattering length density (SLD) depth profiles (Majkrzak, C. F.; Berk, N. F. Physica B 2003, 336, 27) from specular reflectivity measurements. Although a number of scientific applications of PSNR techniques have now been successfully realized (Majkrzak, C. F.; Berk, N. F.; Perez-Salas, U. A. Langmuir 2003, 19, 7796 and references therein), in certain cases practical difficulties remain. In this article, we describe possible solutions to two specific problems: (1) the need for explicit, detailed knowledge of the SLD profile of a given reference layer of finite thickness; and (2) for a reference layer of finite thickness in which only two density variations are possible, how to identify which of two mathematical solutions corresponds to the true physical structure.

Development and evaluation of the Combined Ion and Neutron Spectrometer (CINS)

International Nuclear Information System (INIS)

Zeitlin, C.; Maurer, R.; Roth, D.; Goldsten, J.; Grey, M.

2009-01-01

The Combined Ion and Neutron Spectrometer, CINS, is designed to measure the charged and neutral particles that contribute to the radiation dose and dose equivalent received by humans in spaceflight. As the depth of shielding increases, either onboard a spacecraft or in a surface habitat, the relative contribution of neutrons increases significantly, so that obtaining accurate neutron spectra becomes a critical part of any dosimetric measurements. The spectrometer system consists of high- and medium-energy neutron detectors along with a charged-particle detector telescope based on a standard silicon stack concept. The present version of the design is intended for ground-based use at particle accelerators; future iterations of the design can easily be streamlined to reduce volume, mass, and power consumption to create an instrument package suitable for spaceflight. The detector components have been tested separately using high-energy heavy ion beams at the NASA Space Radiation Laboratory at the Brookhaven National Laboratory and neutron beams at the Radiological Research Accelerator Facility operated by Columbia University. Here, we review the progress made in fabricating the hardware, report the results of several test runs, and discuss the remaining steps necessary to combine the separate components into an integrated system. A custom data acquisition system built for CINS is described in an accompanying article.

Application of californium-252 neutron sources for analytical chemistry

International Nuclear Information System (INIS)

Ishii, Daido

1976-01-01

The researches made for the application of Cf-252 neutron sources to analytical chemistry during the period from 1970 to 1974 including partly 1975 are reviewed. The first part is the introduction to the above. The second part deals with general review of symposia, publications and the like. Attention is directed to ERDA publishing the periodical ''Californium-252 Progress'' and to a study group of Cf-252 utilization held by Japanese Radioisotope Association in 1974. The third part deals with its application for radio activation analysis. The automated absolute activation analysis (AAAA) of Savannha River is briefly explained. The joint experiment of Savannha River operation office with New Brunswick laboratory is mentioned. Cf-252 radiation source was used for the non-destructive analysis of elements in river water. East neutrons of Cf-252 were used for the quantitative analysis of lead in paints. Many applications for industrial control processes have been reported. Attention is drawn to the application of Cf-252 neutron sources for the field search of neutral resources. For example, a logging sonde for searching uranium resources was developed. the fourth part deals with the application of the analysis with gamma ray by capturing neutrons. For example, a bore hole sonde and the process control analysis of sulfur in fuel utilized capture gamma ray. The prompt gamma ray by capturing neutrons may be used for the nondestructive analysis of enrivonment. (Iwakiri, K.)

Pulsed neutron uranium borehole logging with prompt fission neutrons

International Nuclear Information System (INIS)

Bivens, H.M.; Smith, G.W.; Jensen, D.H.

1976-01-01

The gross count natural gamma log normally used for uranium borehole logging is seriously affected by disequilibrium. Methods for the direct measurement of uranium, such as neutron logging, which are not affected by disequilibrium have been the object of considerable effort in recent years. This paper describes a logging system for uranium which uses a small accelerator to generate pulses of 14 MeV neutrons to detect and assay uranium by the measurement of prompt fission neutrons in the epithermal energy range. After an initial feasibility study, a prototype logging probe was built for field evaluation which began in January 1976. Physical and operational characteristics of the prototype probe, the neutron tube-transformer assembly, and the neutron tube are described. In logging operations, only the epithermal prompt fission neutrons detected between 250 microseconds to 2500 microseconds following the excitation neutron pulse are counted. Comparison of corrected neutron logs with the conventional gross count natural gamma logs and the chemical assays of cores from boreholes are shown. The results obtained with this neutron probe clearly demonstrate its advantages over the gross count natural gamma log, although at this time the accuracy of the neutron log assay is not satisfactory under some conditions. The necessary correction factors for various borehole and formation parameters are being determined and, when applied, should improve the assay accuracy

Neutron reflectometry

International Nuclear Information System (INIS)

Van Well, A.A.

1999-01-01

Neutron research where reflection, refraction, and interference play an essential role is generally referred to as 'neutron optics'. The neutron wavelength, the scattering length density and the magnetic properties of the material determine the critical angle for total reflection. The theoretical background of neutron reflection, experimental methods and the interpretation of reflection data are presented. (K.A.)

Pulsed neutron generator for use with pulsed neutron activation techniques

International Nuclear Information System (INIS)

Rochau, G.E.

1980-01-01

A high-output, transportable, pulsed neutron generator has been developed by Sandia National Laboratories for use with Pulsed Neutron Activation (PNA) techniques. The PNA neutron generator generates > 10 10 14 MeV D-T neutrons in a 1.2 millisecond pulse. Each operation of the unit will produce a nominal total neutron output of 1.2 x 10 10 neutrons. The generator has been designed to be easily repaired and modified. The unit requires no additional equipment for operation or measurement of output

Neutron nuclear physics under the neutron science project

Energy Technology Data Exchange (ETDEWEB)

Chiba, Satoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1997-11-01

The concept of fast neutron physics facility in the Neutron Science Research project is described. This facility makes use of an ultra-short proton pulse (width < 1 ns) for fast neutron time-of-flight works. The current design is based on an assumption of the maximum proton current of 100 {mu}A. Available neutron fluence and energy resolution are explained. Some of the research subjects to be performed at this facility are discussed. (author)

Development of highly effective neutron shields and neutron absorbing materials

International Nuclear Information System (INIS)

Tsuda, K.; Matsuda, F.; Taniuchi, H.; Yuhara, T.; Iida, T.

1993-01-01

A wide range of materials, including polymers and hydrogen-occluded alloys that might be usable as the neutron shielding material were examined. And a wide range of materials, including aluminum alloys that might be usable as the neutron-absorbing material were examined. After screening, the candidate material was determined on the basis of evaluation regarding its adaptabilities as a high-performance neutron-shielding and neutron-absorbing material. This candidate material was manufactured for trial, after which material properties tests, neutron-shielding tests and neutron-absorbing tests were carried out on it. The specifications of this material were thus determined. This research has resulted in materials of good performance; a neutron-shielding material based on ethylene propylene rubber and titanium hydride, and a neutron-absorbing material based on aluminum and titanium hydride. (author)

Methods for absorbing neutrons

Science.gov (United States)

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

2012-07-24

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.

Fusion Energy Division annual progress report period ending December 31, 1986

Energy Technology Data Exchange (ETDEWEB)

Morgan, O.B. Jr.; Berry, L.A.; Sheffield, J.

1987-10-01

This annual report on fusion energy discusses the progress on work in the following main topics: toroidal confinement experiments; atomic physics and plasma diagnostics development; plasma theory and computing; plasma-materials interactions; plasma technology; superconducting magnet development; fusion engineering design center; materials research and development; and neutron transport. (LSP)

Fusion Energy Division annual progress report period ending December 31, 1986

International Nuclear Information System (INIS)

Morgan, O.B. Jr.; Berry, L.A.; Sheffield, J.

1987-10-01

This annual report on fusion energy discusses the progress on work in the following main topics: toroidal confinement experiments; atomic physics and plasma diagnostics development; plasma theory and computing; plasma-materials interactions; plasma technology; superconducting magnet development; fusion engineering design center; materials research and development; and neutron transport

Neutron scattering. Lectures

International Nuclear Information System (INIS)

Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

2013-01-01

The following topics are dealt with: Neutron sources, symmetry of crystals, nanostructures investigated by small-angle neutron scattering, structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic neutron scattering, strongly correlated electrons, polymer dynamics, applications of neutron scattering. (HSI)

Development of Cold Neutron Activation Station at HANARO Cold Neutron Source

International Nuclear Information System (INIS)

Sun, G. M.; Hoang, S. M. T.; Moon, J. H.; Chung, Y. S.; Cho, S. J.; Lee, K. H.; Park, B. G.; Choi, H. D.

2012-01-01

A new cold neutron source at the HANARO Research Reactor had been constructed in the framework of a five-year project, and ended in 2009. It has seven neutron guides, among which five guides were already allocated for a number of neutron scattering instruments. A new two-year project to develop a Cold Neutron Activation Station (CONAS) was carried out at the two neutron guides since May 2010, which was supported by the program of the Ministry of Education, Science and Technology, Korea. Fig. 1 shows the location of CONAS. CONAS is a complex facility including several radioanalytical instruments utilizing neutron capture reaction to analyze elements in a sample. It was designed to include three instruments like a CN-PGAA (Cold Neutron - Prompt Gamma Activation Analysis), a CN-NIPS (Cold Neutron - Neutron Induced Pair Spectrometer), and a CN-NDP (Cold Neutron - Neutron-induced prompt charged particle Depth Profiling). Fig. 2 shows the conceptual configuration of the CONAS concrete bioshield and the instruments. CN-PGAA and CN-NIPS measure the gamma-rays promptly emitted from the sample after neutron capture, whereas CN-NDP is a probe to measure the charged particles emitted from the sample surface after neutron capture. For this, we constructed two cold neutron guides called CG1 and CG2B guides from the CNS

SiC-based neutron detector in quasi-realistic working conditions: efficiency and stability at room and high temperature under fast neutron irradiations

Energy Technology Data Exchange (ETDEWEB)

Ferone, Raffaello; Issa, Fatima; Ottaviani, Laurent; Biondo, Stephane; Vervisch, Vanessa [IM2NP, UMR CNRS 7334, Aix-Marseille University, Case 231,13397 Marseille Cedex 20, (France); Szalkai, Dora; Klix, Axel [KIT- Karlsruhe Institute of Technology, Institute of Neutron Physics and Reactor Technology Karlsruhe 76344, (Germany); Vermeeren, Ludo [SCK-CEN, Boeretang 200, B-2400 Mol, (Belgium); Saenger, Richard [Schlumberger, Clamart, (France); Lyoussi, Abadallah [CEA, DEN, Departement d' Etudes des Reacteurs, Service de Physique Experimentale, Laboratoire Dosimetrie Capteurs Instrumentation, 13108 Saint-Paul-lez-Durance, (France)

2015-07-01

In the framework of the European I SMART project, we have designed and made new SiC-based nuclear radiation detectors able to operate in harsh environments and to detect both fast and thermal neutrons. In this paper, we report experimental results of fast neutron irradiation campaign at high temperature (106 deg. C) in quasi-realistic working conditions. Our device does not suffer from high temperature, and spectra do show strong stability, preserving features. These experiments, as well as others in progress, show the I SMART SiC-based device skills to operate in harsh environments, whereas other materials would strongly suffer from degradation. Work is still demanded to test our device at higher temperatures and to enhance efficiency in order to make our device fully exploitable from an industrial point of view. (authors)

The magnetic diffusion of neutrons; La diffusion magnetique des neutrons

Energy Technology Data Exchange (ETDEWEB)

Koehler, W C [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1959-07-01

The purpose of this report is to examine briefly the diffusion of neutrons by substances, particularly by crystals containing permanent atomic or ionic magnetic moments. In other words we shall deal with ferromagnetic, antiferromagnetic, ferrimagnetic or paramagnetic crystals, but first it is necessary to touch on nuclear diffusion of neutrons. We shall start with the interaction of the neutron with a single diffusion centre; the results will then be applied to the magnetic interactions of the neutron with the satellite electrons of the atom; finally we shall discuss the diffusion of neutrons by crystals. (author) [French] Le but de ce rapport est d'examiner, brievement, la diffusion des neutrons par les substances, et surtout, par des cristaux qui contiennent des moments magnetiques atomiques ou ioniques permanents. C'est-a-dire que nous nous interesserons aux cristaux ferromagnetiques, antiferromagnetiques, ferrimagnetiques ou paramagnetiques; il nous faut cependant rappeler d'abord la diffusion nucleaire des neutrons. Nous commencerons par l'interaction du neutron avec un seul centre diffuseur; puis les resultats seront appliques aux interactions magnetiques du neutron avec les electrons satellites de l'atome; enfin nous discuterons la diffusion des neutrons par les cristaux. (auteur)

Progress report on FNCA activities in 2003

International Nuclear Information System (INIS)

Machi, Sueo

2005-01-01

The progress of FNCA (Forum for Nuclear Cooperation in Asia) activities in 2003 and the future plan, reported at the 4th FNCA meeting - Ministerial level and senior official meetings, are described. The project proposal from Malaysia on application and usage of positron emission tomography, cyclotron and radioisotopes in medicine and also the panel-set up proposal from Japan on role of nuclear energy for sustainable development of Asia were approved with the recognition of the human resources development as most important for sustainability of nuclear science and technology. The other activities highlighted are: enhancement of research reactor technology for effective utilization, application of accelerators, neutron activation analysis for monitoring airborne particulates, Tc-99m generator production, neutron scattering, mutation breeding, bio-fertilizer, radiation oncology, public information for nuclear energy, radioactive waste management, and nuclear safety culture. (S. Ohno)

Neutron scattering. Lectures

Energy Technology Data Exchange (ETDEWEB)

Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

2010-07-01

The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)

Neutron scattering. Lectures

International Nuclear Information System (INIS)

Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

2010-01-01

The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)

Neutron Stars and Black Holes New clues from Chandra and XMM-Newton

CERN Multimedia

CERN. Geneva. Audiovisual Unit

2002-01-01

Neutron stars and black holes, the most compact astrophysical objects, have become observable in many different ways during the last few decades. We will first review the phenomenology and properties of neutron stars and black holes (stellar and supermassive) as derived from multiwavelength observatories. Recently much progress has been made by means of the new powerful X-ray observatories Chandra and XMM-Newton which provide a substantial increase in sensitivity as well as spectral and angular resolution compared with previous satellites like ROSAT and ASCA. We shall discuss in more detail two recent topics: (1) The attempts to use X-ray spectroscopy for measuring the radii of neutron stars which depend on the equation of state at supranuclear densities. Have quark stars been detected? (2) The diagnostics of the strong gravity regions around supermassive black holes using X-ray spectroscopy.

The Manuel Lujan, Jr. Neutron Scattering Center (LANSCE) experiment reports 1992 run cycle. Progress report

Energy Technology Data Exchange (ETDEWEB)

DiStravolo, M.A. [comp.

1993-09-01

This year was the fifth in which LANSCE ran a formal user program. A call for proposals was issued before the scheduled run cycles, and experiment proposals were submitted by scientists from universities, industry, and other research facilities around the world. An external program advisory committee, which LANSCE shares with the Intense Pulsed Neutron Source (IPNS), Argonne National Laboratory, examined the proposals and made recommendations. At LANSCE, neutrons are produced by spallation when a pulsed, 800-MeV proton beam impinges on a tungsten target. The proton pulses are provided by the Clinton P. Anderson Meson Physics Facility (LAMPF) accelerator and an associated Proton Storage Ring (PSR), which can alter the intensity, time structure, and repetition rate of the pulses. The LAMPF protons of Line D are shared between the LANSCE target and the Weapons Neutron Research (WNR) facility, which results in LANSCE spectrometers being available to external users for unclassified research about 80% of each annual LAMPF run cycle. Measurements of interest to the Los Alamos National Laboratory may also be performed and may occupy up to an additional 20% of the available beam time. These experiments are reviewed by an internal program advisory committee. One hundred sixty-seven proposals were submitted for unclassified research and twelve proposals for research of a programmatic interest to the Laboratory; six experiments in support of the LANSCE research program were accomplished during the discretionary periods. Oversubscription for instrument beam time by a factor of three was evident with 839 total days requested and only 371 available for allocation.

Neutron polarization

International Nuclear Information System (INIS)

Firk, F.W.K.

1976-01-01

Some recent experiments involving polarized neutrons are discussed; they demonstrate how polarization studies provide information on fundamental aspects of nuclear structure that cannot be obtained from more traditional neutron studies. Until recently, neutron polarization studies tended to be limited either to very low energies or to restricted regions at higher energies, determined by the kinematics of favorable (p, vector n) and (d, vector n) reactions. With the advent of high intensity pulsed electron and proton accelerators and of beams of vector polarized deuterons, this is no longer the case. One has entered an era in which neutron polarization experiments are now being carried out, in a routine way, throughout the entire range from thermal energies to tens-of-MeV. The significance of neutron polarization studies is illustrated in discussions of a wide variety of experiments that include the measurement of T-invariance in the β-decay of polarized neutrons, a search for the effects of meson exchange currents in the photo-disintegration of the deuteron, the determination of quantum numbers of states in the fission of aligned 235 U and 237 Np induced by polarized neutrons, and the double- and triple-scattering of fast neutrons by light nuclei

Comparison of the cytological effects produced by ionizing radiations of different LET. Progress report, March 1974--April 1975

International Nuclear Information System (INIS)

Riley, E.F. Jr.

1975-01-01

Progress is reported on the following research projects: RBE of neutrons and x radiation for effects on rat lens epithelium; effects of x radiation on tumor cell transplants in mice; effects of fast neutrons on ascites tumors; the sparing effect of dose fractionation in the wounded rat lens; and DNA synthesis in wounded rat lens at various times after irradiation. (U.S.)

Considerations for boron neutron capture therapy studies

International Nuclear Information System (INIS)

Faria Gaspar, P. de.

1994-01-01

Radiotherapy is indispensable as a mean to eradicate deeply or infiltrating tumor tissue that can not be removed surgically. Therefore, it is not selective and may also kill the surrounding health tissue. The principle of BNCT (Boron Neutron Capture Therapy) consist in targeting a tumor selectively with a boron-10 compound. This nuclide has a large capture cross section for thermal neutrons and the nuclear reaction and the delivered energy in locus will selective the tumor. Since its initial proposal in 1963 BNCT has made much progress, however it is not used in a routine treatment. In this work it was approached some complex procedures, as the obtention of selective boron compounds, the adequate set up of neutron beams, the biodistribution, the in vivo and in vitro studies, and also human patients treatments. This work provide fundamentals about BNCT to professional of different areas of knowledge since it comprises multidisciplinary study. It includes appendixes for the ones not related to the field for a better comprehension of the many aspects involved. It is also presented a glossary containing technical and basic aspects involved. It is also presented a glossary containing technical and basic terms referred in the work. (author). 174 refs, 1 fig, 12 apps

Neutron imaging integrated circuit and method for detecting neutrons

Science.gov (United States)

Nagarkar, Vivek V.; More, Mitali J.

2017-12-05

The present disclosure provides a neutron imaging detector and a method for detecting neutrons. In one example, a method includes providing a neutron imaging detector including plurality of memory cells and a conversion layer on the memory cells, setting one or more of the memory cells to a first charge state, positioning the neutron imaging detector in a neutron environment for a predetermined time period, and reading a state change at one of the memory cells, and measuring a charge state change at one of the plurality of memory cells from the first charge state to a second charge state less than the first charge state, where the charge state change indicates detection of neutrons at said one of the memory cells.

Neutron reflector design with Californium 252 neutron for Boron neutron chapter therapy facility using MCNP5 simulation method

International Nuclear Information System (INIS)

Muhammad Fakhrurreza; Kusminanto; Y Sardjono

2014-01-01

In this research has made a reflector design to provide beams of Neutron for BNCT with Californium-252 radioactive source. This collimator is useful to obtain optimum epithermal neutron flux with the smallest impurity radiation (thermal neutron, fast neutron, and gamma). The design process is done using Monte Carlo N-Particle simulation version 5 (MCNP5) code to calculate the neutron flux tally form. The chosen reflector design is the reflectors which use material such as BeO ceramic with 13 cm thick. Moderator use sulfur material with the slope angle of the cone is 30°. From the calculation result, it is obtained that Reflector with 1 gram Californium-252 source can produce a neutron output thermal which has thermal neutron specification 2.23189 x 10 9 n/s.cm 2 , epithermal neutron 3.51548 x 10 9 n/s.cm 2 , and fast neutron 4.82241 x 10 9 n/s.cm 2 From the result, it needs additional collimator because the BNCT requirement. (author)

Neutron spectometers

International Nuclear Information System (INIS)

Poortmans, F.

1977-01-01

Experimental work in the field of low-energy neutron physics can be subdivided into two classes: 1)Study of the decay process of the compound-nucleus state as for example the study of the capture gamma rays and of the neutron induced fission process; 2)Study of the reaction mechanism, mainly by measuring the reaction cross-sections and resonance parameters. These neutron cross-sections and resonance parameters are also important data required for many technological applications especially for reactor development programmes. In general, the second class of experiments impose other requirements on the neutron spectrometer than the first class. In most cases, a better neutron energy resolution and a broader neutron energy range are required for the study of the reaction mechanism than for the study of various aspects of the decay process. (author)

Neutron scattering. Lectures

International Nuclear Information System (INIS)

Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

2012-01-01

The following topics are dealt with: Neutron scattering in contemporary research, neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)

Aerial Neutron Detection: Neutron Signatures for Nonproliferation and Emergency Response Applications

Energy Technology Data Exchange (ETDEWEB)

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.

2012-10-17

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.

Synovectomy by Neutron capture; Sinovectomia por captura de neutrones

Energy Technology Data Exchange (ETDEWEB)

Vega C, H.R.; Torres M, C. [Centro Regional de Estudios Nucleares, Universidad Autonoma de Zacatecas, C. Cipres 10, Fracc. La Penuela, 98000 Zacatecas (Mexico)

1998-12-31

The Synovectomy by Neutron capture has as purpose the treatment of the rheumatoid arthritis, illness which at present does not have a definitive curing. This therapy requires a neutron source for irradiating the articulation affected. The energy spectra and the intensity of these neutrons are fundamental since these neutrons induce nuclear reactions of capture with Boron-10 inside the articulation and the freely energy of these reactions is transferred at the productive tissue of synovial liquid, annihilating it. In this work it is presented the neutron spectra results obtained with moderator packings of spherical geometry which contains in its center a Pu{sup 239} Be source. The calculations were realized through Monte Carlo method. The moderators assayed were light water, heavy water base and the both combination of them. The spectra obtained, the average energy, the neutron total number by neutron emitted by source, the thermal neutron percentage and the dose equivalent allow us to suggest that the moderator packing more adequate is what has a light water thickness 0.5 cm (radius 2 cm) and 24.5 cm heavy water (radius 26.5 cm). (Author)

Assessing neutron generator output using neutron activation of silicon

International Nuclear Information System (INIS)

Kehayias, Pauli M.; Kehayias, Joseph J.

2007-01-01

D-T neutron generators are used for elemental composition analysis and medical applications. Often composition is determined by examining elemental ratios in which the knowledge of the neutron flux is unnecessary. However, the absolute value of the neutron flux is required when the generator is used for neutron activation analysis, to study radiation damage to materials, to monitor the operation of the generator, and to measure radiation exposure. We describe a method for absolute neutron output and flux measurements of low output D-T neutron generators using delayed activation of silicon. We irradiated a series of silicon oxide samples with 14.1 MeV neutrons and counted the resulting gamma rays of the 28 Al nucleus with an efficiency-calibrated detector. To minimize the photon self-absorption effects within the samples, we used a zero-thickness extrapolation technique by repeating the measurement with samples of different thicknesses. The neutron flux measured 26 cm away from the tritium target of a Thermo Electron A-325 D-T generator (Thermo Electron Corporation, Colorado Springs, CO) was 6.2 x 10 3 n/s/cm 2 ± 5%, which is consistent with the manufacturer's specifications

Assessing neutron generator output using neutron activation of silicon

Energy Technology Data Exchange (ETDEWEB)

Kehayias, Pauli M. [Body Composition Laboratory, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111 (United States); Kehayias, Joseph J. [Body Composition Laboratory, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111 (United States)]. E-mail: joseph.kehayias@tufts.edu

2007-08-15

D-T neutron generators are used for elemental composition analysis and medical applications. Often composition is determined by examining elemental ratios in which the knowledge of the neutron flux is unnecessary. However, the absolute value of the neutron flux is required when the generator is used for neutron activation analysis, to study radiation damage to materials, to monitor the operation of the generator, and to measure radiation exposure. We describe a method for absolute neutron output and flux measurements of low output D-T neutron generators using delayed activation of silicon. We irradiated a series of silicon oxide samples with 14.1 MeV neutrons and counted the resulting gamma rays of the {sup 28}Al nucleus with an efficiency-calibrated detector. To minimize the photon self-absorption effects within the samples, we used a zero-thickness extrapolation technique by repeating the measurement with samples of different thicknesses. The neutron flux measured 26 cm away from the tritium target of a Thermo Electron A-325 D-T generator (Thermo Electron Corporation, Colorado Springs, CO) was 6.2 x 10{sup 3} n/s/cm{sup 2} {+-} 5%, which is consistent with the manufacturer's specifications.

Neutron scattering studies of the dynamics of biopolymer-water systems using pulsed-source spectrometers

Energy Technology Data Exchange (ETDEWEB)

Middendorf, H.D. [Univ. of Oxford (United Kingdom); Miller, A. [Stirling Univ., Stirling (United Kingdom)

1994-12-31

Energy-resolving neutron scattering techniques provide spatiotemporal data suitable for testing and refining analytical models or computer simulations of a variety of dynamical processes in biomolecular systems. This paper reviews experimental work on hydrated biopolymers at ISIS, the UK Pulsed Neutron Facility. Following an outline of basic concepts and a summary of the new instrumental capabilities, the progress made is illustrated by results from recent experiments in two areas: quasi- elastic scattering from highly hydrated polysaccharide gels (agarose and hyaluronate), and inelastic scattering from vibrational modes of slightly hydrated collagen fibers.

Neutron scattering studies of the dynamics of biopolymer-water systems using pulsed-source spectrometers

International Nuclear Information System (INIS)

Middendorf, H.D.; Miller, A.

1994-01-01

Energy-resolving neutron scattering techniques provide spatiotemporal data suitable for testing and refining analytical models or computer simulations of a variety of dynamical processes in biomolecular systems. This paper reviews experimental work on hydrated biopolymers at ISIS, the UK Pulsed Neutron Facility. Following an outline of basic concepts and a summary of the new instrumental capabilities, the progress made is illustrated by results from recent experiments in two areas: quasi- elastic scattering from highly hydrated polysaccharide gels (agarose and hyaluronate), and inelastic scattering from vibrational modes of slightly hydrated collagen fibers

Hyper-thermal neutron irradiation field for neutron capture therapy

International Nuclear Information System (INIS)

Sakurai, Yoshinori; Kobayashi, Tooru; Kanda, Keiji

1994-01-01

The utilization of hyper-thermal neutrons, which have an energy spectrum of a Maxwell distribution higher than the room temperature of 300 K, has been studied in order to improve the thermal neutron flux distribution in a living body for a deep-seated tumor in neutron capture therapy (NCT). Simulation calculations using MCNP-V3 were carried out in order to investigate the characteristics of the hyper-thermal neutron irradiation field. From the results of simulation calculations, the following were confirmed: (i) The irradiation field of the hyper-thermal neutrons is feasible by using some scattering materials with high temperature, such as Be, BeO, C, SiC and ZrH 1.7 . Especially, ZrH 1.7 is thought to be the best material because of good characteristics of up-scattering for thermal neutrons. (ii) The ZrH 1.7 of 1200 K yields the hyper-thermal neutrons of a Maxwell-like distribution at about 2000 K and the treatable depth is about 1.5 cm larger comparing with the irradiation of the thermal neutrons of 300 K. (iii) The contamination by the secondary gamma-rays from the scattering materials can be sufficiently eliminated to the tolerance level for NCT through the bismuth layer, without the larger change of the energy spectrum of hyper-thermal neutrons. ((orig.))

Effects of neutron spectrum and external neutron source on neutron multiplication parameters in accelerator-driven system

International Nuclear Information System (INIS)

Shahbunder, Hesham; Pyeon, Cheol Ho; Misawa, Tsuyoshi; Lim, Jae-Yong; Shiroya, Seiji

2010-01-01

The neutron multiplication parameters: neutron multiplication M, subcritical multiplication factor k s , external source efficiency φ*, play an important role for numerical assessment and reactor power evaluation of an accelerator-driven system (ADS). Those parameters can be evaluated by using the measured reaction rate distribution in the subcritical system. In this study, the experimental verification of this methodology is performed in various ADS cores; with high-energy (100 MeV) proton-tungsten source in hard and soft neutron spectra cores and 14 MeV D-T neutron source in soft spectrum core. The comparison between measured and calculated multiplication parameters reveals a maximum relative difference in the range of 6.6-13.7% that is attributed to the calculation nuclear libraries uncertainty and accuracy for energies higher than 20 MeV and also dependent on the reaction rate distribution position and count rates. The effects of different core neutron spectra and external neutron sources on the neutron multiplication parameters are discussed.

Neutron dosimetry at SLAC: Neutron sources and instrumentation

International Nuclear Information System (INIS)

Liu, J.C.; Jenkins, T.M.; McCall, R.C.; Ipe, N.E.

1991-10-01

This report summarizes in detail the dosimetric characteristics of the five radioisotopic type neutron sources ( 238 PuBe, 252 Cf, 238 PuB, 238 PuF 4 , and 238 PuLi) and the neutron instrumentation (moderated BF 3 detector, Anderson-Braun (AB) detector, AB remmeter, Victoreen 488 Neutron Survey Meter, Beam Shut-Off Ionization Chamber, 12 C plastic scintillator detector, moderated indium foil detector, and moderated and bare TLDs) that are commonly used for neutron dosimetry at the Stanford Linear Accelerator Center (SLAC). 36 refs,. 19 figs

Production of 14 MeV neutrons from D-D neutron generators

International Nuclear Information System (INIS)

Cecil, F.E.; Nieschmidt, E.B.

1986-01-01

The production of 14 MeV neutrons from a D-D neutron generator resulting from tritium buildup from the d(d,p)t reaction in the target is discussed. The effect of the 14 MeV neutrons on fast neutron activation analysis with D-D neutron generators is evaluated. (orig.)

Pulsed neutron generator

International Nuclear Information System (INIS)

Bespalov, D.F.; Bykovskii, Yu.A.; Vergun, I.I.; Kozlovskii, K.I.; Kozyrev, Yu.P.; Leonov, R.K.; Simagin, B.I.; Tsybin, A.S.; Shikanov, A.Ie.

1986-03-01

The paper describes a new device for generating pulsed neutron fields, utilized in nuclear geophysics for carrying out pulsed neutron logging and activation analysis under field conditions. The invention employs a sealed-off neutron tube with a laser ion source which increases neutron yield to the level of 10 neutrons per second or higher. 2 refs., 1 fig

Study of structure of nuclei with neutrons and nuclear data measurements for MFE

International Nuclear Information System (INIS)

Lane, R.O.; Grimes, S.M.

1990-01-01

Measurements and analysis of cross sections for neutron-induced reactions of interest to the fusion energy program have been carried out. These include neutron elastic and inelastic cross sections for 2 H, 10 B and 13 C as well as cross sections for 54 Fe and 56 Fe (n,z) reactions. Most of these data have been analyzed using either R-matrix studies or Hauser-Feshbach calculations. Details of these measurements and analyses are given. Level density measurements and low energy optical model studies for protons have been completed to improve our understanding of (n,z) reactions. Total cross section measurements have also been analyzed to obtain optical model information. Improvements to the facilities at this laboratory are also described. Modifications to the shell model code have enabled further progress to be made in studies of nuclear structure and reaction mechanisms. A description of the code and summary of the structure and level density calculations now in progress are given

Neutron PSDs for the next generation of spallation neutron sources

CERN Document Server

Eijk, C W

2002-01-01

A review of R and D for neutron PSDs to be used at anticipated new spallation neutron sources: the Time-of-Flight system facility, European Spallation Source, Spallation Neutron Source and Neutron Arena, is presented. The gas-filled detectors, scintillation detectors and hybrid systems are emphasized.

New neutron imaging using pulsed sources. Characteristics of a pulsed neutron source and principle of pulsed neutron imaging

International Nuclear Information System (INIS)

Kiyanagi, Yoshiaki

2012-01-01

Neutron beam is one of important tools to obtain the transmission image of an object. Until now, steady state neutron sources such as reactors are mainly used for this imaging purpose. Recently, it has been demonstrated that pulsed neutron imaging based on accelerator neutron sources can provide a real-space distribution of physical information of materials such as crystallographic structure, element, temperature, hydrogen bound state, magnetic field and so on, by analyzing wavelength dependent transmission spectrum, which information cannot be observed or difficult to obtain with a traditional imaging method using steady state neutrons. Here, characteristics of the pulsed neutron source and principle of the pulsed neutron imaging are explained as a basic concept of the new method. (author)

Neutron guides and scientific neutron equipment at CILAS/GMI

International Nuclear Information System (INIS)

Gautier-Picard, P.

2003-01-01

CILAS company is the world's leading supplier of complete neutron guides systems. The neutron optics with multilayer coatings produced by CILAS have become an international standard for neutron beam transportation in the modern research institutes. During the last 30 years, CILAS designed, produced and installed more than 5000 meters of guides in many European, American and Asian countries. To reinforce its leadership and presence in neutron research, CILAS acquired the company Grenoble Modular Instruments (GMI), a leading company in high precision mechanics, engineering and manufacturing of spectrometers and scientific equipment for neutron and synchrotron research. (author)

Monte Carlo simulation of secondary neutron dose for scanning proton therapy using FLUKA.

Directory of Open Access Journals (Sweden)

Chaeyeong Lee

Full Text Available Proton therapy is a rapidly progressing field for cancer treatment. Globally, many proton therapy facilities are being commissioned or under construction. Secondary neutrons are an important issue during the commissioning process of a proton therapy facility. The purpose of this study is to model and validate scanning nozzles of proton therapy at Samsung Medical Center (SMC by Monte Carlo simulation for beam commissioning. After the commissioning, a secondary neutron ambient dose from proton scanning nozzle (Gantry 1 was simulated and measured. This simulation was performed to evaluate beam properties such as percent depth dose curve, Bragg peak, and distal fall-off, so that they could be verified with measured data. Using the validated beam nozzle, the secondary neutron ambient dose was simulated and then compared with the measured ambient dose from Gantry 1. We calculated secondary neutron dose at several different points. We demonstrated the validity modeling a proton scanning nozzle system to evaluate various parameters using FLUKA. The measured secondary neutron ambient dose showed a similar tendency with the simulation result. This work will increase the knowledge necessary for the development of radiation safety technology in medical particle accelerators.

Neutron detector

Science.gov (United States)

Stephan, Andrew C [Knoxville, TN; Jardret,; Vincent, D [Powell, TN

2011-04-05

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.

Determination and analysis of neutron flux distribution on radial Piercing beam port for utilization of Kartini research reactor

International Nuclear Information System (INIS)

Widarto

2002-01-01

Determination and analysis of neutron flux measurements on radial piercing beam port have been done as completion experimental data document and progressing on utilization of the Kartini research reactor purposes. The analysis and determination of the neutron flux have been carried out by using Au foils detector neutron activation analysis method which put on the radius of cross section (19 cm) and a long of radial piercing beam port (310 cm) Based on the calculation, distribution of the thermal neutron flux is around (8.3 ± 0.9) x 10 5 ncm -2 s -1 to (6.8 ± 0.5) x 10 7 ncm -2 s -1 and fast neutron is (5.0 ± 0.2) x 10 5 ncm -2 s -1 to (1.43 ± 0.6) x 10 7 ncm -2 s -1 . Analyzing by means of curve fitting method could be concluded that the neutron flux distribution on radial piercing beam port has profiled as a polynomial curve. (author)

Development of fast neutron radiography system based on portable neutron generator

Energy Technology Data Exchange (ETDEWEB)

Yi, Chia Jia, E-mail: gei-i-kani@hotmail.com; Nilsuwankosit, Sunchai, E-mail: sunchai.n@chula.ac.th [Department of Nuclear Engineering, Faculty of Engineering, Chulalongkorn University, Phayathai Rd., Patumwan, Bangkok, THAILAND 10330 (Thailand)

2016-01-22

Due to the high installation cost, the safety concern and the immobility of the research reactors, the neutron radiography system based on portable neutron generator is proposed. Since the neutrons generated from a portable neutron generator are mostly the fast neutrons, the system is emphasized on using the fast neutrons for the purpose of conducting the radiography. In order to suppress the influence of X-ray produced by the neutron generator, a combination of a shielding material sandwiched between two identical imaging plates is used. A binary XOR operation is then applied for combining the information from the imaging plates. The raw images obtained confirm that the X-ray really has a large effect and that XOR operation can help enhance the effect of the neutrons.

Neutron dosimetry at SLAC: Neutron sources and instrumentation

Energy Technology Data Exchange (ETDEWEB)

Liu, J.C.; Jenkins, T.M.; McCall, R.C.; Ipe, N.E.

1991-10-01

This report summarizes in detail the dosimetric characteristics of the five radioisotopic type neutron sources ({sup 238}PuBe, {sup 252}Cf, {sup 238}PuB, {sup 238}PuF{sub 4}, and {sup 238}PuLi) and the neutron instrumentation (moderated BF{sub 3} detector, Anderson-Braun (AB) detector, AB remmeter, Victoreen 488 Neutron Survey Meter, Beam Shut-Off Ionization Chamber, {sup 12}C plastic scintillator detector, moderated indium foil detector, and moderated and bare TLDs) that are commonly used for neutron dosimetry at the Stanford Linear Accelerator Center (SLAC). 36 refs,. 19 figs.

Directional epithermal neutron detector

International Nuclear Information System (INIS)

Givens, W.W.; Mills, W.R. Jr.

1986-01-01

A borehole tool for epithermal neutron die-away logging of subterranean formations surrounding a borehole is described which consists of: (a) a pulsed source of fast neutrons for irradiating the formations surrounding a borehole, (b) at least one neutron counter for counting epithermal neutrons returning to the borehole from the irradiated formations, (c) a neutron moderating material, (d) an outer thermal neutron shield providing a housing for the counter and the moderating material, (e) an inner thermal neutron shield dividing the housing so as to provide a first compartment bounded by the inner thermal neutron shield and a first portion of the outer thermal neutron shield and a second compartment bounded by the inner thermal neutron shield and a second portion of the outer thermal neutron shield, the counter being positioned within the first compartment and the moderating material being positioned within the second compartment, and (f) means for positioning the borehole tool against one side of the borehole wall and azimuthally orienting the borehole tool such that the first chamber is in juxtaposition with the borehole wall, the formation epithermal neutrons penetrating into the first chamber through the first portion of the outer thermal neutron shield are detected by the neutron counter for die-away measurement, thereby maximizing the directional sensitivty of the neutron counter to formation epithermal neutrons, the borehole fluid epithermal neutrons penetrating into the second chamber through the second chamber through the second portion of the outer thermal neutron shield are largely slowed down and lowered in energy by the moderating material and absorbed by the inner thermal neutron shield before penetrating into the first chamber, thereby minimizing the directional sensitivity of the neutron counter to borehole fluid epithermal neutrons

Neutron Optics: Towards Applications for Hot Neutrons

International Nuclear Information System (INIS)

Schanzer, C; Schneider, M; Böni, P

2016-01-01

Supermirrors with large critical angles of reflection, i.e. large index m are an essential ingredient to transport, focus and polarise neutrons over a wide range of energy. Here we summarise the recent developments of supermirror with very large critical angles of reflection and high reflectivity that were conducted at SwissNeutronics as well as their implementation in devices. Approaching critical angles m = 8 times the critical angle of natural nickel makes new applications possible and extends the use of reflection optics towards the regime of hot and epithermal neutrons. Based on comparisons of simulations with experiment we demonstrate future possibilities of applications of large-m supermirrors towards devices for neutrons with short wavelength. (paper)

Survey on neutron production by electron beam from high power CW electron linear accelerator

International Nuclear Information System (INIS)

Toyama, S.

1999-04-01

In Japan Nuclear Cycle Development Institute, the development of high current CW electron linear accelerator is in progress. It is possible for an accelerator to produce neutrons by means of a spallation and photo nuclear reactions. Application of neutron beam produced by bremsstrahlung is one of ways of the utilization for high current electron accelerator. It is actual that many electron linear accelerators which maximum energy is higher than a few hundreds MeV are used as neutron sources. In this report, an estimate of neutron production is evaluated for high current CW electron linear accelerator. The estimate is carried out by 10 MeV beam which is maximum energy limited from the regulation and rather low for neutron production. Therefore, the estimate is also done by 17 and 35 MeV beam which is possible to be accelerated. Beryllium is considered as a target for lower electron energy in addition to Lead target for higher energy, because Beryllium has low threshold energy for neutron production. The evaluation is carried out in account of the target thickness optimized by the radiation length and neutron cross section reducing the energy loss for both of electron and neutron, so as to get the maximum number of neutrons. The result of the calculations shows neutron numbers 1.9 x 10 10 , 6.1 x 10 13 and 4.8 x 10 13 (n/s), respectively, for 10, 17, and 35 MeV with low duty. The thermal removal from the target is one of critical points. The additional shielding and cooling system is necessary in order to endure radiation. A comparison with other facilities are also carried out. The estimate of neutron numbers suggests the possibility to be applied for neutron radiography and measurement of nuclear data by means of Lead spectrometer, for example. (author)

Progress report 1999-2000

International Nuclear Information System (INIS)

2000-01-01

This document presents the activities of the CENBG for the 1999 and 2000 years. The activities are arranged into 7 topics: 1) astro-particles, 2) high spins and big deformations, 3) fundamental interactions, 4) exotic nuclei, 5) the down end of the nuclear fuel cycle and ADS (accelerator driven system), 6) theoretical physics and 7) at the interface between physics and biology. Among a lot of achievements relevant to INIS we can note: -) the investigation of 2 new modes of decay: the bound internal conversion and the Pauli forbidden bound internal conversion, -) the progress made on the Nemo-3 experiment whose purpose is the possibility of detecting the neutrinoless double beta decay from the kinematics specificities of the 2 electrons released, -) the first observation of the doubly-magic nucleus Ni 48 , -) the beta delayed proton and gamma -ray spectroscopy of Mg 21 and Si 25 nuclei, -) the identification of the fundamental state of Li 10 , -) the measurement of the masses of nuclei close to N = Z line in the region A = 80, -) the measurement of the beta decay of Ga 62 (T = 116 ms), and concerning ADS technology: -) the neutron capture cross-section of Th 232 has been measured in the energy range from 60 keV to 2 MeV, -) the determination of neutron induced fission cross-section of Pa 233 in the fast neutron energy range from 0.5 to 10 MeV, and -) the measurement of isotopic distributions for all residual elements from Ti to Pb produced in the reaction 1 A.GeV Pb 208 on proton. (A.C.)

Computational methods for the nuclear and neutron matter problem. Progress report

International Nuclear Information System (INIS)

Kalos, M.H.; Carlson, J.; Panoff, R.; Schmidt, K.

1985-10-01

A new method is presented for treating fermion systems by Monte Carlo methods. This method is based on the concept of a ''mirror potential,'' which is a many-body potential that forces the Monte Carlo iteration to have a stable anti-symmetric component. The potential may be determined from the wave function and, within the framework of Green's Function Monte Carlo (GFMC), from the random walk whose density converges to the wave function. Further work has been given to the variational study of light nuclei. In particular, microscopic calculations of alpha-neutron scattering were performed. Techniques were also developed for performing variational calculations of heavier nuclei interacting with realistic interactions. A series of calculations on liquid 3 He at its experimental equilibrium density has also been done. 42 refs

A Review of Significant Advances in Neutron Imaging from Conception to the Present

Science.gov (United States)

Brenizer, J. S.

This review summarizes the history of neutron imaging with a focus on the significant events and technical advancements in neutron imaging methods, from the first radiograph to more recent imaging methods. A timeline is presented to illustrate the key accomplishments that advanced the neutron imaging technique. Only three years after the discovery of the neutron by English physicist James Chadwick in 1932, neutron imaging began with the work of Hartmut Kallmann and Ernst Kuhn in Berlin, Germany, from 1935-1944. Kallmann and Kuhn were awarded a joint US Patent issued in January 1940. Little progress was made until the mid-1950's when Thewlis utilized a neutron beam from the BEPO reactor at Harwell, marking the beginning of the application of neutron imaging to practical applications. As the film method was improved, imaging moved from a qualitative to a quantitative technique, with applications in industry and in nuclear fuels. Standards were developed to aid in the quantification of the neutron images and the facility's capabilities. The introduction of dynamic neutron imaging (initially called real-time neutron radiography and neutron television) in the late 1970's opened the door to new opportunities and new challenges. As the electronic imaging matured, the introduction of the CCD imaging devices and solid-state light intensifiers helped address some of these challenges. Development of improved imaging devices for the medical community has had a major impact on neutron imaging. Additionally, amorphous silicon sensors provided improvements in temporal resolution, while providing a reasonably large imaging area. The development of new neutron imaging sensors and the development of new neutron imaging techniques in the past decade has advanced the technique's ability to provide insight and understanding of problems that other non-destructive techniques could not provide. This rapid increase in capability and application would not have been possible without the

Activation Inventories after Exposure to DD/DT Neutrons in Safety Analysis of Nuclear Fusion Installations.

Science.gov (United States)

Stankunas, Gediminas; Cufar, Aljaz; Tidikas, Andrius; Batistoni, Paola

2017-11-23

Irradiations with 14 MeV fusion neutrons are planned at Joint European Torus (JET) in DT operations with the objective to validate the calculation of the activation of structural materials in functional materials expected in ITER and fusion plants. This study describes the activation and dose rate calculations performed for materials irradiated throughout the DT plasma operation during which the samples of real fusion materials are exposed to 14 MeV neutrons inside the JET vacuum vessel. Preparatory activities are in progress during the current DD operations with dosimetry foils to measure the local neutron fluence and spectrum at the sample irradiation position. The materials included those used in the manufacturing of the main in-vessel components, such as ITER-grade W, Be, CuCrZr, 316 L(N) and the functional materials used in diagnostics and heating systems. The neutron-induced activities and dose rates at shutdown were calculated by the FISPACT code, using the neutron fluxes and spectra that were provided by the preceding MCNP neutron transport calculations. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Neutron transportation simulator

International Nuclear Information System (INIS)

Uenohara, Yuzo.

1995-01-01

In the present invention, problems in an existent parallelized monte carlo method is solved, and behaviors of neutrons in a large scaled system are accurately simulated at a high speed. Namely, a neutron transportation simulator according to the monte carlo method simulates movement of each of neutrons by using a parallel computer. In this case, the system to be processed is divided based on a space region and an energy region to which neutrons belong. Simulation of neutrons in the divided regions is allotted to each of performing devices of the parallel computer. Tarry data and nuclear data of the neutrons in each of the regions are memorized dispersedly to memories of each of the performing devices. A transmission means for simulating the behaviors of the neutrons in the region by each of the performing devices, as well as transmitting the information of the neutrons, when the neutrons are moved to other region, to the performing device in a transported portion are disposed to each of the performing devices. With such procedures, simulation for the neutrons in the allotted region can be conducted with small capacity of memories. (I.S.)

Neutronics of the IFMIF neutron source: development and analysis

International Nuclear Information System (INIS)

Wilson, P.P.H.

1999-01-01

The accurate analysis of this system required the development of a code system and methodology capable of modelling the various physical processes. A generic code system for the neutronics analysis of neutron sources has been created by loosely integrating existing components with new developments: the data processing code NJOY, the Monte Carlo neutron transport code MCNP, and the activation code ALARA were supplemented by a damage data processing program, damChar, and integrated with a number of flexible and extensible modules for the Perl scripting language. Specific advances were required to apply this code system to IFMIF. Based on the ENDF-6 data format requirements of this system, new data evaluations have been implemented for neutron transport and activation. Extensive analysis of the Li(d, xn) reaction has led to a new MCNP source function module, M c DeLi, based on physical reaction models and capable of accurate and flexible modelling of the IFMIF neutron source term. In depth analyses of the neutron flux spectra and spatial distribution throughout the high flux test region permitted a basic validation of the tools and data. The understanding of the features of the neutron flux provided a foundation for the analyses of the other neutron responses. (orig./DGE) [de

Neutron spectra and dosimetric features of isotopic neutron sources: a review

International Nuclear Information System (INIS)

Vega C, H. R.; Martinez O, S. A.

2015-10-01

A convenient way to produce neutrons is the isotopic neutron source, where the production is through (α, n), (γ, n), and spontaneous fission reactions. Isotopic neutron sources are small, easy to handle, and have a relative low cost. On the other hand the neutron yield is small and mostly of them produces neutrons with a wide energy distribution. In this work, a review is carried out about the the main features of 24 NaBe, 24 NaD 2 O, 116 InBe, 140 LaBe, 238 PuLi, 239 PuBe, 241 AmB, 241 AmBe, 241 AmF, 241 AmLi, 242 CmBe, 210 PoBe, 226 RaBe, 252 Cf and 252 Cf/D 2 O isotopic neutron source. Also, using Monte Carlo methods, the neutron spectra in 31 energy groups, the neutron mean energy; the Ambient dose equivalent, the Personal dose equivalent and the Effective dose were calculated for these isotopic neutron sources. (Author)

A neutron detector for measurement of total neutron production cross sections

International Nuclear Information System (INIS)

Sekharan, K.K.; Laumer, H.; Kern, B.D.; Gabbard, F.

1976-01-01

A neutron detector has been constructed and calibrated for the accurate measurement of total neutron production cross sections. The detector consists of a polyethylene sphere of 60 cm diameter in which eight 10 BF 3 counters have been installed radially. The relative efficiency of this detector has been determined for average neutron energies from 30 keV to 1.5 MeV by counting neutrons from 7 Li(p, n) 7 Be. By adjusting the radial positions of the BF 3 counters in the polyethylene sphere the efficiency for neutron detection was made nearly constant for this energy range. Measurement of absolute efficiency for the same neutron energy range has been done by counting the neutrons from 51 V(p, n) 51 Cr and 57 Fe(p, n) 57 Co reactions and determining the absolute number of residual nuclei produced during the measurement of neutron yield. Details of absolute efficiency measurements and the use of the detector for determination of neutron production cross sections are given. (Auth.)

Fusion neutronics

CERN Document Server

Wu, Yican

2017-01-01

This book provides a systematic and comprehensive introduction to fusion neutronics, covering all key topics from the fundamental theories and methodologies, as well as a wide range of fusion system designs and experiments. It is the first-ever book focusing on the subject of fusion neutronics research. Compared with other nuclear devices such as fission reactors and accelerators, fusion systems are normally characterized by their complex geometry and nuclear physics, which entail new challenges for neutronics such as complicated modeling, deep penetration, low simulation efficiency, multi-physics coupling, etc. The book focuses on the neutronics characteristics of fusion systems and introduces a series of theories and methodologies that were developed to address the challenges of fusion neutronics, and which have since been widely applied all over the world. Further, it introduces readers to neutronics design’s unique principles and procedures, experimental methodologies and technologies for fusion systems...

Neutron-induced peaks in Ge detectors from evaporation neutrons

International Nuclear Information System (INIS)

Gete, E.; Measday, D.F.; Moftah, B.A.; Saliba, M.A.; Stocki, T.J.

1997-01-01

We have studied the peak shapes at 596 and 691 keV resulting from fast neutron interactions inside germanium detectors. We have used neutrons from a 252 Cf source, as well as from the 28 Si(μ - , nν), and 209 Bi(π - , xn) reactions to compare the peaks and to check for a dependence of peak shape on the incoming neutron energy. In our investigation, no difference between these three measurements has been observed. In a comparison of these peak shapes with other studies, we found similar results to ours except for those measurements using monoenergetic neutrons in which a significant variation with neutron energy has been observed. (orig.)

Development of high flux thermal neutron generator for neutron activation analysis

Energy Technology Data Exchange (ETDEWEB)

Vainionpaa, Jaakko H., E-mail: hannes@adelphitech.com [Adelphi Technology, 2003 E Bayshore Rd, Redwood City, CA 94063 (United States); Chen, Allan X.; Piestrup, Melvin A.; Gary, Charles K. [Adelphi Technology, 2003 E Bayshore Rd, Redwood City, CA 94063 (United States); Jones, Glenn [G& J Jones Enterprice, 7486 Brighton Ct, Dublin, CA 94568 (United States); Pantell, Richard H. [Department of Electrical Engineering, Stanford University, Stanford, CA (United States)

2015-05-01

The new model DD110MB neutron generator from Adelphi Technology produces thermal (<0.5 eV) neutron flux that is normally achieved in a nuclear reactor or larger accelerator based systems. Thermal neutron fluxes of 3–5 · 10{sup 7} n/cm{sup 2}/s are measured. This flux is achieved using four ion beams arranged concentrically around a target chamber containing a compact moderator with a central sample cylinder. Fast neutron yield of ∼2 · 10{sup 10} n/s is created at the titanium surface of the target chamber. The thickness and material of the moderator is selected to maximize the thermal neutron flux at the center. The 2.5 MeV neutrons are quickly thermalized to energies below 0.5 eV and concentrated at the sample cylinder. The maximum flux of thermal neutrons at the target is achieved when approximately half of the neutrons at the sample area are thermalized. In this paper we present simulation results used to characterize performance of the neutron generator. The neutron flux can be used for neutron activation analysis (NAA) prompt gamma neutron activation analysis (PGNAA) for determining the concentrations of elements in many materials. Another envisioned use of the generator is production of radioactive isotopes. DD110MB is small enough for modest-sized laboratories and universities. Compared to nuclear reactors the DD110MB produces comparable thermal flux but provides reduced administrative and safety requirements and it can be run in pulsed mode, which is beneficial in many neutron activation techniques.

Hazards control progress report No. 54, January--June 1977

International Nuclear Information System (INIS)

1977-01-01

Progress in the protection of personnel includes: the development of a thermoluminescent albedo neutron dosimeter; the development of a method for the detection of small quantities of Pu in human lungs by tissue density measurements and photon transmission scanning; monitoring of pesticide residues in surface waters; monitoring work areas for the presence of chemical carcinogens; and evaluation of ventilation systems and the fire safety of buildings

Finite volume thermal-hydraulics and neutronics coupled calculations - 15300

International Nuclear Information System (INIS)

Araujo Silva, V.; Campagnole dos Santos, A.A.; Mesquit, A.Z.; Bernal, A.; Miro, R.; Verdu, G.; Pereira, C.

2015-01-01