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Sample records for accelerator neutron source

  1. An Accelerator Neutron Source for BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Blue, Thomas, E

    2006-03-14

    The overall goal of this project was to develop an accelerator-based neutron source (ABNS) for Boron Neutron Capture Therapy (BNCT). Specifically, our goals were to design, and confirm by measurement, a target assembly and a moderator assembly that would fulfill the design requirements of the ABNS. These design requirements were 1) that the neutron field quality be as good as the neutron field quality for the reactor-based neutron sources for BNCT, 2) that the patient treatment time be reasonable, 3) that the proton current required to treat patients in reasonable times be technologially achievable at reasonable cost with good reliability, and accelerator space requirements which can be met in a hospital, and finally 4) that the treatment be safe for the patients.

  2. An Accelerator Neutron Source for BNCT

    International Nuclear Information System (INIS)

    The overall goal of this project was to develop an accelerator-based neutron source (ABNS) for Boron Neutron Capture Therapy (BNCT). Specifically, our goals were to design, and confirm by measurement, a target assembly and a moderator assembly that would fulfill the design requirements of the ABNS. These design requirements were (1) that the neutron field quality be as good as the neutron field quality for the reactor-based neutron sources for BNCT, (2) that the patient treatment time be reasonable, (3) that the proton current required to treat patients in reasonable times be technologically achievable at reasonable cost with good reliability, and accelerator space requirements which can be met in a hospital, and finally (4) that the treatment be safe for the patients

  3. The Spallation Neutron Source accelerator system design

    Science.gov (United States)

    Henderson, S.; Abraham, W.; Aleksandrov, A.; Allen, C.; Alonso, J.; Anderson, D.; Arenius, D.; Arthur, T.; Assadi, S.; Ayers, J.; Bach, P.; Badea, V.; Battle, R.; Beebe-Wang, J.; Bergmann, B.; Bernardin, J.; Bhatia, T.; Billen, J.; Birke, T.; Bjorklund, E.; Blaskiewicz, M.; Blind, B.; Blokland, W.; Bookwalter, V.; Borovina, D.; Bowling, S.; Bradley, J.; Brantley, C.; Brennan, J.; Brodowski, J.; Brown, S.; Brown, R.; Bruce, D.; Bultman, N.; Cameron, P.; Campisi, I.; Casagrande, F.; Catalan-Lasheras, N.; Champion, M.; Champion, M.; Chen, Z.; Cheng, D.; Cho, Y.; Christensen, K.; Chu, C.; Cleaves, J.; Connolly, R.; Cote, T.; Cousineau, S.; Crandall, K.; Creel, J.; Crofford, M.; Cull, P.; Cutler, R.; Dabney, R.; Dalesio, L.; Daly, E.; Damm, R.; Danilov, V.; Davino, D.; Davis, K.; Dawson, C.; Day, L.; Deibele, C.; Delayen, J.; DeLong, J.; Demello, A.; DeVan, W.; Digennaro, R.; Dixon, K.; Dodson, G.; Doleans, M.; Doolittle, L.; Doss, J.; Drury, M.; Elliot, T.; Ellis, S.; Error, J.; Fazekas, J.; Fedotov, A.; Feng, P.; Fischer, J.; Fox, W.; Fuja, R.; Funk, W.; Galambos, J.; Ganni, V.; Garnett, R.; Geng, X.; Gentzlinger, R.; Giannella, M.; Gibson, P.; Gillis, R.; Gioia, J.; Gordon, J.; Gough, R.; Greer, J.; Gregory, W.; Gribble, R.; Grice, W.; Gurd, D.; Gurd, P.; Guthrie, A.; Hahn, H.; Hardek, T.; Hardekopf, R.; Harrison, J.; Hatfield, D.; He, P.; Hechler, M.; Heistermann, F.; Helus, S.; Hiatt, T.; Hicks, S.; Hill, J.; Hill, J.; Hoff, L.; Hoff, M.; Hogan, J.; Holding, M.; Holik, P.; Holmes, J.; Holtkamp, N.; Hovater, C.; Howell, M.; Hseuh, H.; Huhn, A.; Hunter, T.; Ilg, T.; Jackson, J.; Jain, A.; Jason, A.; Jeon, D.; Johnson, G.; Jones, A.; Joseph, S.; Justice, A.; Kang, Y.; Kasemir, K.; Keller, R.; Kersevan, R.; Kerstiens, D.; Kesselman, M.; Kim, S.; Kneisel, P.; Kravchuk, L.; Kuneli, T.; Kurennoy, S.; Kustom, R.; Kwon, S.; Ladd, P.; Lambiase, R.; Lee, Y. Y.; Leitner, M.; Leung, K.-N.; Lewis, S.; Liaw, C.; Lionberger, C.; Lo, C. C.; Long, C.; Ludewig, H.; Ludvig, J.; Luft, P.; Lynch, M.; Ma, H.; MacGill, R.; Macha, K.; Madre, B.; Mahler, G.; Mahoney, K.; Maines, J.; Mammosser, J.; Mann, T.; Marneris, I.; Marroquin, P.; Martineau, R.; Matsumoto, K.; McCarthy, M.; McChesney, C.; McGahern, W.; McGehee, P.; Meng, W.; Merz, B.; Meyer, R.; Meyer, R.; Miller, B.; Mitchell, R.; Mize, J.; Monroy, M.; Munro, J.; Murdoch, G.; Musson, J.; Nath, S.; Nelson, R.; Nelson, R.; O`Hara, J.; Olsen, D.; Oren, W.; Oshatz, D.; Owens, T.; Pai, C.; Papaphilippou, I.; Patterson, N.; Patterson, J.; Pearson, C.; Pelaia, T.; Pieck, M.; Piller, C.; Plawski, T.; Plum, M.; Pogge, J.; Power, J.; Powers, T.; Preble, J.; Prokop, M.; Pruyn, J.; Purcell, D.; Rank, J.; Raparia, D.; Ratti, A.; Reass, W.; Reece, K.; Rees, D.; Regan, A.; Regis, M.; Reijonen, J.; Rej, D.; Richards, D.; Richied, D.; Rode, C.; Rodriguez, W.; Rodriguez, M.; Rohlev, A.; Rose, C.; Roseberry, T.; Rowton, L.; Roybal, W.; Rust, K.; Salazer, G.; Sandberg, J.; Saunders, J.; Schenkel, T.; Schneider, W.; Schrage, D.; Schubert, J.; Severino, F.; Shafer, R.; Shea, T.; Shishlo, A.; Shoaee, H.; Sibley, C.; Sims, J.; Smee, S.; Smith, J.; Smith, K.; Spitz, R.; Staples, J.; Stein, P.; Stettler, M.; Stirbet, M.; Stockli, M.; Stone, W.; Stout, D.; Stovall, J.; Strelo, W.; Strong, H.; Sundelin, R.; Syversrud, D.; Szajbler, M.; Takeda, H.; Tallerico, P.; Tang, J.; Tanke, E.; Tepikian, S.; Thomae, R.; Thompson, D.; Thomson, D.; Thuot, M.; Treml, C.; Tsoupas, N.; Tuozzolo, J.; Tuzel, W.; Vassioutchenko, A.; Virostek, S.; Wallig, J.; Wanderer, P.; Wang, Y.; Wang, J. G.; Wangler, T.; Warren, D.; Wei, J.; Weiss, D.; Welton, R.; Weng, J.; Weng, W.-T.; Wezensky, M.; White, M.; Whitlatch, T.; Williams, D.; Williams, E.; Wilson, K.; Wiseman, M.; Wood, R.; Wright, P.; Wu, A.; Ybarrolaza, N.; Young, K.; Young, L.; Yourd, R.; Zachoszcz, A.; Zaltsman, A.; Zhang, S.; Zhang, W.; Zhang, Y.; Zhukov, A.

    2014-11-01

    The Spallation Neutron Source (SNS) was designed and constructed by a collaboration of six U.S. Department of Energy national laboratories. The SNS accelerator system consists of a 1 GeV linear accelerator and an accumulator ring providing 1.4 MW of proton beam power in microsecond-long beam pulses to a liquid mercury target for neutron production. The accelerator complex consists of a front-end negative hydrogen-ion injector system, an 87 MeV drift tube linear accelerator, a 186 MeV side-coupled linear accelerator, a 1 GeV superconducting linear accelerator, a 248-m circumference accumulator ring and associated beam transport lines. The accelerator complex is supported by ~100 high-power RF power systems, a 2 K cryogenic plant, ~400 DC and pulsed power supply systems, ~400 beam diagnostic devices and a distributed control system handling ~100,000 I/O signals. The beam dynamics design of the SNS accelerator is presented, as is the engineering design of the major accelerator subsystems.

  4. The Spallation Neutron Source accelerator system design

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, S., E-mail: stuarth@fnal.gov [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Abraham, W. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Aleksandrov, A. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Allen, C. [Techsource, Inc., 1475 Central Avenue, Suite 250, Los Alamos, NM 87544-3291 (United States); Alonso, J. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Anderson, D. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Arenius, D. [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Avenue, Newport News, VA 23606 (United States); Arthur, T. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Assadi, S. [Techsource, Inc., 1475 Central Avenue, Suite 250, Los Alamos, NM 87544-3291 (United States); Ayers, J.; Bach, P. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Badea, V. [Brookhaven National Laboratory, P.O. Box 5000, Upton, NY 11973-5000 (United States); Battle, R. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Beebe-Wang, J. [Brookhaven National Laboratory, P.O. Box 5000, Upton, NY 11973-5000 (United States); Bergmann, B.; Bernardin, J.; Bhatia, T.; Billen, J.; Birke, T.; Bjorklund, E. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); and others

    2014-11-01

    The Spallation Neutron Source (SNS) was designed and constructed by a collaboration of six U.S. Department of Energy national laboratories. The SNS accelerator system consists of a 1 GeV linear accelerator and an accumulator ring providing 1.4 MW of proton beam power in microsecond-long beam pulses to a liquid mercury target for neutron production. The accelerator complex consists of a front-end negative hydrogen-ion injector system, an 87 MeV drift tube linear accelerator, a 186 MeV side-coupled linear accelerator, a 1 GeV superconducting linear accelerator, a 248-m circumference accumulator ring and associated beam transport lines. The accelerator complex is supported by ∼100 high-power RF power systems, a 2 K cryogenic plant, ∼400 DC and pulsed power supply systems, ∼400 beam diagnostic devices and a distributed control system handling ∼100,000 I/O signals. The beam dynamics design of the SNS accelerator is presented, as is the engineering design of the major accelerator subsystems.

  5. High Intensity Accelerator and Neutron Source in China

    Science.gov (United States)

    Guan, Xialing; Wei, J.; Loong, Chun

    2011-06-01

    High intensity Accelerator is being studied all over world for numerous applications, which includes the waste transmutation, spallation neutron source and material irradiation facilities. The R/D activities of the technology of High intensity accelerator are also developed in China for some year, and have some good facilities around China. This paper will reports the status of some high intensity accelerators and neutron source in China, which including ADS/RFQ; CARR; CSNS; PKUNIFTY & CPHS. This paper will emphatically report the Compact Pulsed Hadron Source (CPHS) led by the Department of Engineering Physics of Tsinghua University in Beijing, China.

  6. Research opportunities with compact accelerator-driven neutron sources

    Science.gov (United States)

    Anderson, I. S.; Andreani, C.; Carpenter, J. M.; Festa, G.; Gorini, G.; Loong, C.-K.; Senesi, R.

    2016-10-01

    Since the discovery of the neutron in 1932 neutron beams have been used in a very broad range of applications, As an aging fleet of nuclear reactor sources is retired the use of compact accelerator-driven neutron sources (CANS) is becoming more prevalent. CANS are playing a significant and expanding role in research and development in science and engineering, as well as in education and training. In the realm of multidisciplinary applications, CANS offer opportunities over a wide range of technical utilization, from interrogation of civil structures to medical therapy to cultural heritage study. This paper aims to provide the first comprehensive overview of the history, current status of operation, and ongoing development of CANS worldwide. The basic physics and engineering regarding neutron production by accelerators, target-moderator systems, and beam line instrumentation are introduced, followed by an extensive discussion of various evolving applications currently exploited at CANS.

  7. Pulsed neutron source based on accelerator-subcritical-assembly

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Makoto; Noda, Akira; Iwashita, Yoshihisa; Okamoto, Hiromi; Shirai, Toshiyuki [Kyoto Univ., Uji (Japan). Inst. for Chemical Research

    1997-03-01

    A new pulsed neutron source which consists of a 300MeV proton linac and a nuclear fuel subcritical assembly is proposed. The proton linac produces pulsed spallation neutrons, which are multipied by the subcritical assembly. A prototype proton linac that accelerates protons up to 7MeV has been developed and a high energy section of a DAW structure is studied with a power model. Halo formations in high intensity beam are also being studied. (author)

  8. Measurement of subcriticality using delayed neutron source combined with pulsed neutron accelerator

    International Nuclear Information System (INIS)

    A new experimental method for subcriticality measurement was developed by using delayed neutron source which is produced by external pulsed neutron source to increase accuracy of measured results by overcoming the space dependency problem which means difference of measured results in different detector position and often appeared in almost all other subcriticality measurement techniques. Experiments were performed at Kyoto University Critical Assembly (KUCA) combined with a DT accelerator to produce pulsed neutron in outside of the core repeatedly. In this method, neutron detection counts in the prompt neutron time region which are appeared just after injection of pulsed neutron are omitted, whereas neutron counts in the delayed neutron time region which are appeared after disappearance of exponential decay of the prompt neutron are adopted in analysis based on neutron source multiplication method or neutron noise analysis method; the variance to mean ratio method. In the delayed neutron time region, neutron sources to initiate fission chain reactions in subcritical state are delayed neutrons from delayed neutron precursors which are mainly produced by fission chain reactions in the prompt neutron time region, and delayed neutron precursors exist only in the fuel region, which makes possible to decrease the space dependency problem. The obtained results were compared with conventional pulsed neutron method, and it was found that the space dependency problem in subcriticality measurement can be fairly decreased by using the present new method compared with conventional one. (author)

  9. Electron accelerator shielding design of KIPT neutron source facility

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Zhao Peng; Gohar, Yousry [Argonne National Laboratory, Argonne (United States)

    2016-06-15

    The Argonne National Laboratory of the United States and the Kharkov Institute of Physics and Technology of the Ukraine have been collaborating on the design, development and construction of a neutron source facility at Kharkov Institute of Physics and Technology utilizing an electron-accelerator-driven subcritical assembly. The electron beam power is 100 kW using 100-MeV electrons. The facility was designed to perform basic and applied nuclear research, produce medical isotopes, and train nuclear specialists. The biological shield of the accelerator building was designed to reduce the biological dose to less than 5.0e-03 mSv/h during operation. The main source of the biological dose for the accelerator building is the photons and neutrons generated from different interactions of leaked electrons from the electron gun and the accelerator sections with the surrounding components and materials. The Monte Carlo N-particle extended code (MCNPX) was used for the shielding calculations because of its capability to perform electron-, photon-, and neutron-coupled transport simulations. The photon dose was tallied using the MCNPX calculation, starting with the leaked electrons. However, it is difficult to accurately tally the neutron dose directly from the leaked electrons. The neutron yield per electron from the interactions with the surrounding components is very small, ∼0.01 neutron for 100-MeV electron and even smaller for lower-energy electrons. This causes difficulties for the Monte Carlo analyses and consumes tremendous computation resources for tallying the neutron dose outside the shield boundary with an acceptable accuracy. To avoid these difficulties, the SOURCE and TALLYX user subroutines of MCNPX were utilized for this study. The generated neutrons were banked, together with all related parameters, for a subsequent MCNPX calculation to obtain the neutron dose. The weight windows variance reduction technique was also utilized for both neutron and photon dose

  10. Accelerator-based neutron source for the neutron-capture and fast neutron therapy at hospital

    Science.gov (United States)

    Bayanov, B. F.; Belov, V. P.; Bender, E. D.; Bokhovko, M. V.; Dimov, G. I.; Kononov, V. N.; Kononov, O. E.; Kuksanov, N. K.; Palchikov, V. E.; Pivovarov, V. A.; Salimov, R. A.; Silvestrov, G. I.; Skrinsky, A. N.; Soloviov, N. A.; Taskaev, S. Yu.

    The proton accelerator complex for neutron production in lithium target discussed, which can operate in two modes. The first provides a neutron beam kinematically collimated with good forward direction in 25° and average energy of 30 keV, directly applicable for neutron-capture therapy with high efficiency of proton beam use. The proton energy in this mode is 1.883-1.890 MeV that is near the threshold of the 7Li( p, n) 7Be reaction. In the second mode, at proton energy of 2.5 MeV, the complex-produced neutron beam with maximum energy board of 790 keV which can be used directly for fast neutron therapy and for neutron-capture therapy after moderation. The project of such a neutron source is based on the 2.5 MeV original electrostatic accelerator tandem with vacuum insulation developed at BINP which is supplied with a high-voltage rectifier. The rectifier is produced in BINP as a part of ELV-type industrial accelerator. Design features of the tandem determining its high reliability in operation with a high-current (up to 40 mA) H - ion beam are discussed. They are: the absence of ceramic accelerator columns around the beam passage region, good conditions for pumping out of charge-exchange gaseous target region, strong focusing optics and high acceleration rate minimizing the space charge effects. The possibility of stabilization of protons energy with an accuracy level of 0.1% necessary for operation in the near threshold region is considered. The design description of H - continuous ion source with a current of 40 mA is also performed. To operate with a 100 kW proton beam it is proposed to use liquid-lithium targets. A thin lithium layer on the surface of a tungsten disk cooled intensively by a liquid metal heat carrier is proposed for use in case of the vertical beam, and a flat liquid lithium jet flowing through the narrow nozzle - for the horizontal beam.

  11. Accelerator based neutron source for the neutron capture therapy at hospital

    International Nuclear Information System (INIS)

    Accelerator source of epithermal neutrons for the hospital-based boron neutron capture therapy is proposed and discussed. Kinematically collimated neutrons are produced via near-threshold 7Li(p, n)7Be reaction at proton energies of 1.883 - 1.9 MeV. Steady-state accelerator current of 40 mA allows to provide therapeutically useful beams with treatment times of tens of minutes. The basic components of the facility are a hydrogen negative ion source, an electrostatic tandem accelerator with vacuum insulation, a sectioned rectifier, and a thin lithium neutron generating target on the surface of tungsten disk cooled by liquid metal heat carrier. Design features of facility components are discussed. The possibility of stabilization of proton energy is considered. At proton energy of 2.5 MeV the neutron beam production for NCT usage after moderation is also considered. (author)

  12. A high power accelerator driver system for spallation neutron sources

    International Nuclear Information System (INIS)

    This is the final report of a two-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). For several years, the Los Alamos Meson Physics Facility (LAMPF) and the Proton Storage Ring (PSR) have provided a successful driver for the nearly 100-kW Los Alamos Neutron Scattering Center (LANSCE) source. The authors have studied an upgrade to this system. The goal of this effort was to establish a credible design for the accelerator driver of a next-generation source providing 1-MW of beam power. They have explored a limited subset of the possible approaches to a driver and have considered only the low 1-MW beam power. The next-generation source must utilize the optimum technology and may require larger neutron intensities than they now envision

  13. Prospect for application of compact accelerator-based neutron source to neutron engineering diffraction

    Science.gov (United States)

    Ikeda, Yoshimasa; Taketani, Atsushi; Takamura, Masato; Sunaga, Hideyuki; Kumagai, Masayoshi; Oba, Yojiro; Otake, Yoshie; Suzuki, Hiroshi

    2016-10-01

    A compact accelerator-based neutron source has been lately discussed on engineering applications such as transmission imaging and small angle scattering as well as reflectometry. However, nobody considers using it for neutron diffraction experiment because of its low neutron flux. In this study, therefore, the neutron diffraction experiments are carried out using Riken Accelerator-driven Compact Neutron Source (RANS), to clarify the capability of the compact neutron source for neutron engineering diffraction. The diffraction pattern from a ferritic steel was successfully measured by suitable arrangement of the optical system to reduce the background noise, and it was confirmed that the recognizable diffraction pattern can be measured by a large sampling volume with 10 mm in cubic for an acceptable measurement time, i.e. 10 min. The minimum resolution of the 110 reflection for RANS is approximately 2.5% at 8 μs of the proton pulse width, which is insufficient to perform the strain measurement by neutron diffraction. The moderation time width at the wavelength corresponding to the 110 reflection is estimated to be approximately 30 μs, which is the most dominant factor to determine the resolution. Therefore, refinements of the moderator system to decrease the moderation time by decreasing a thickness of the moderator or by applying the decoupler system or application of the angular dispersive neutron diffraction technique are important to improve the resolution of the diffraction experiment using the compact neutron source. In contrast, the texture evolution due to plastic deformation was successfully observed by measuring a change in the diffraction peak intensity by RANS. Furthermore, the volume fraction of the austenitic phase in the dual phase mock specimen was also successfully evaluated by fitting the diffraction pattern using a Rietveld code. Consequently, RANS has been proved to be capable for neutron engineering diffraction aiming for the easy access

  14. Simulation and optimization for a 30-MeV electron accelerator driven neutron source

    International Nuclear Information System (INIS)

    A neutron source driven by electron accelerator is proposed in Shanghai Institute of Applied Physics (SINAP). The facility is planned for the study of nuclear data in Thorium-Uranium cycling system, and for material research. A detailed simulation of the neutron source is performed for the program to get the neutron generation maximum economically. Several parameters of the facility, which affect the neutron yield and the neutron escape from outer surface of the target, are analyzed respectively. Besides, the yielding neutron spectrum and the escaping neutron angular distribution are calculated and discussed. (authors)

  15. Development opportunities for small and medium scale accelerator driven neutron sources. Proceedings of a technical meeting

    International Nuclear Information System (INIS)

    Neutron applications in the life sciences will be a rapidly growing research area in the near future, as neutrons can provide unique information on the reaction dynamics of complex biomolecular systems, complementing other analytical techniques such as electron microscopy, X rays and nuclear magnetic resonance. Small and medium power spallation neutron sources will become more important, as many small neutron producing research reactors are being phased out. Recent developments in accelerator technology have made it possible to produce useful neutron fluxes at accelerator facilities suitable for universities and industrial laboratories. In addition to basic research these alternative neutron sources will be important for educational and training purposes. In a wider perspective this technology should make it possible to introduce neutron research and applications to industrial and national research centres in IAEA Member States that are unable to afford a high energy spallation neutron source and have no access to a research reactor

  16. Optimizing Laser-accelerated Ion Beams for a Collimated Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    C.L. Ellison and J. Fuchs

    2010-09-23

    High-flux neutrons for imaging and materials analysis applications have typically been provided by accelerator- and reactor-based neutron sources. A novel approach is to use ultraintense (>1018W/cm2) lasers to generate picosecond, collimated neutrons from a dual target configuration. In this article, the production capabilities of present and upcoming laser facilities are estimated while independently maximizing neutron yields and minimizing beam divergence. A Monte-Carlo code calculates angular and energy distributions of neutrons generated by D-D fusion events occurring within a deuterated target for a given incident beam of D+ ions. Tailoring of the incident distribution via laser parameters and microlens focusing modifies the emerging neutrons. Projected neutron yields and distributions are compared to conventional sources, yielding comparable on-target fluxes per discharge, shorter time resolution, larger neutron energies and greater collimation.

  17. An accelerator-based epithermal photoneutron source for boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, H.E.

    1996-04-01

    Boron neutron capture therapy is an experimental binary cancer radiotherapy modality in which a boronated pharmaceutical that preferentially accumulates in malignant tissue is first administered, followed by exposing the tissue in the treatment volume to a thermal neutron field. Current usable beams are reactor-based but a viable alternative is the production of an epithermal neutron beam from an accelerator. Current literature cites various proposed accelerator-based designs, most of which are based on proton beams with beryllium or lithium targets. This dissertation examines the efficacy of a novel approach to BNCT treatments that incorporates an electron linear accelerator in the production of a photoneutron source. This source may help to resolve some of the present concerns associated with accelerator sources, including that of target cooling. The photoneutron production process is discussed as a possible alternate source of neutrons for eventual BNCT treatments for cancer. A conceptual design to produce epithermal photoneutrons by high photons (due to bremsstrahlung) impinging on deuterium targets is presented along with computational and experimental neutron production data. A clinically acceptable filtered epithermal neutron flux on the order of 10{sup 7} neutrons per second per milliampere of electron current is shown to be obtainable. Additionally, the neutron beam is modified and characterized for BNCT applications by employing two unique moderating materials (an Al/AlF{sub 3} composite and a stacked Al/Teflon design) at various incident electron energies.

  18. An accelerator-based epithermal photoneutron source for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Boron neutron capture therapy is an experimental binary cancer radiotherapy modality in which a boronated pharmaceutical that preferentially accumulates in malignant tissue is first administered, followed by exposing the tissue in the treatment volume to a thermal neutron field. Current usable beams are reactor-based but a viable alternative is the production of an epithermal neutron beam from an accelerator. Current literature cites various proposed accelerator-based designs, most of which are based on proton beams with beryllium or lithium targets. This dissertation examines the efficacy of a novel approach to BNCT treatments that incorporates an electron linear accelerator in the production of a photoneutron source. This source may help to resolve some of the present concerns associated with accelerator sources, including that of target cooling. The photoneutron production process is discussed as a possible alternate source of neutrons for eventual BNCT treatments for cancer. A conceptual design to produce epithermal photoneutrons by high photons (due to bremsstrahlung) impinging on deuterium targets is presented along with computational and experimental neutron production data. A clinically acceptable filtered epithermal neutron flux on the order of 107 neutrons per second per milliampere of electron current is shown to be obtainable. Additionally, the neutron beam is modified and characterized for BNCT applications by employing two unique moderating materials (an Al/AlF3 composite and a stacked Al/Teflon design) at various incident electron energies

  19. The Need for a Neutron Source at the Rare Isotope Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Ahle, L E; Rusnak, B; Roberts, K E; Roeben, M D; Hausmann, M; Reifarth, R; Vieira, D

    2005-05-13

    An intense neutron source facility with radiochemical processing capability is necessary at the Rare Isotope Accelerator to fully realize its potential benefit to stockpile stewardship and astrophysics. While many of the important physics missions of RIA can be addressed with radioactive ion beams, direct neutron cross-section measurements of interest to stockpile stewardship and astrophysics cannot because one cannot make a neutron target. Thus, one must collect a sufficient amount of the appropriate short-lived isotope, quickly chemically process the material into a target, and promptly radiate the sample with an intense ''beam'' of neutrons. The unprecedented production rates expected at RIA enables many of these direct neutron cross-section measurements, but only if the proper infrastructure is in place. This document not only describes the major piece of this required infrastructure, a neutron source facility with radiochemical processing capabilities, but also the motivation for measuring such direct neutron cross-sections.

  20. The Argonne ACWL, a potential accelerator-based neutron source for BNCT

    International Nuclear Information System (INIS)

    THE CWDD (Continuous Wave Deuterium Demonstrator) accelerator was designed to accelerate 80 mA cw of D- to 7.5 MeV. Most of the hardware for the first 2 MeV was installed at Argonne and major subsystems had been commissioned when program funding from the Ballistic Missile Defense Organization ended in October 1993. Renamed the Argonne Continuous Wave Linac (ACWL), we are proposing to complete it to accelerate either deuterons to 2 MeV or protons to 3-3.5 MeV. Equipped with a beryllium or other light-element target, it would make a potent source of neutrons (on the order of 1013 n/s) for BNCT and/or neutron radiography. Project status and proposals for turning ACWL into a neutron source are reviewed, including the results of a computational study that was carried out to design a target/moderator to produce an epithermal neutron beam for BNCT. (orig.)

  1. Design of an accelerator-based neutron source for neutron capture therapy

    International Nuclear Information System (INIS)

    The boron neutron capture therapy is mainly suited in the treatment of some tumor kinds which revealed ineffective to the traditional radiotherapy. In order to take advantage of such a therapeutic modality in hospital environments, neutron beams of suitable energy and flux levels provided by compact size facilities are needed. The advantages and drawbacks of several neutron beams are here analysed in terms of therapeutic gains. In detail the GEANT-3/MICAP simulations show that high tumor control probability, with sub-lethal dose at healthy tissues, can be achieved by using neutron beams of few keV energy having a flux of about 109 neutrons/(cm2 s). To produce such a neutron beam, the feasibility of a proton accelerator is investigated. In particular an appropriate choice of the radiofrequency parameters (modulation, efficiency of acceleration, phase shift, etc.) allows the development of relatively compact accelerators, having a proton beam current of 30 mA and an energy of 2 MeV, which could eventually lead to setting up of hospital-based neutron facilities.

  2. Accelerator system of neutron spallation source for nuclear energy technology development

    International Nuclear Information System (INIS)

    High intensity proton accelerators are at present and developed for applications in neutron spallation sources. The advantages of this source are better safety factor, easy in controlling and spent fuel free. A study of conceptual design of required accelerator system has been carried out. Considering the required proton beam and feasibility in the development stages, a stepped linac system is an adequate choice for now

  3. Characterisation of an accelerator-based neutron source for BNCT versus beam energy

    CERN Document Server

    Agosteo, S; D'Errico, F; Nath, R; Tinti, R

    2002-01-01

    Neutron capture in sup 1 sup 0 B produces energetic alpha particles that have a high linear energy transfer in tissue. This results in higher cell killing and a higher relative biological effectiveness compared to photons. Using suitably designed boron compounds which preferentially localize in cancerous cells instead of healthy tissues, boron neutron capture therapy (BNCT) has the potential of providing a higher tumor cure rate within minimal toxicity to normal tissues. This clinical approach requires a thermal neutron source, generally a nuclear reactor, with a fluence rate sufficient to deliver tumorcidal doses within a reasonable treatment time (minutes). Thermal neutrons do not penetrate deeply in tissue, therefore BNCT is limited to lesions which are either superficial or otherwise accessible. In this work, we investigate the feasibility of an accelerator-based thermal neutron source for the BNCT of skin melanomas. The source was designed via MCNP Monte Carlo simulations of the thermalization of a fast ...

  4. Characterisation of an accelerator-based neutron source for BNCT versus beam energy

    Energy Technology Data Exchange (ETDEWEB)

    Agosteo, S. E-mail: stefano.agosteo@polimi.it; Curzio, G.; D' Errico, F.; Nath, R.; Tinti, R

    2002-01-01

    Neutron capture in {sup 10}B produces energetic alpha particles that have a high linear energy transfer in tissue. This results in higher cell killing and a higher relative biological effectiveness compared to photons. Using suitably designed boron compounds which preferentially localize in cancerous cells instead of healthy tissues, boron neutron capture therapy (BNCT) has the potential of providing a higher tumor cure rate within minimal toxicity to normal tissues. This clinical approach requires a thermal neutron source, generally a nuclear reactor, with a fluence rate sufficient to deliver tumorcidal doses within a reasonable treatment time (minutes). Thermal neutrons do not penetrate deeply in tissue, therefore BNCT is limited to lesions which are either superficial or otherwise accessible. In this work, we investigate the feasibility of an accelerator-based thermal neutron source for the BNCT of skin melanomas. The source was designed via MCNP Monte Carlo simulations of the thermalization of a fast neutron beam, generated by 7 MeV deuterons impinging on a thick target of beryllium. The neutron field was characterized at several deuteron energies (3.0-6.5 MeV) in an experimental structure installed at the Van De Graaff accelerator of the Laboratori Nazionali di Legnaro, in Italy. Thermal and epithermal neutron fluences were measured with activation techniques and fast neutron spectra were determined with superheated drop detectors (SDD). These neutron spectrometry and dosimetry studies indicated that the fast neutron dose is unacceptably high in the current design. Modifications to the current design to overcome this problem are presented.

  5. ESS-Bilbao light-ion linear accelerator and neutron source: design and applications

    International Nuclear Information System (INIS)

    The baseline design for the ESS-Bilbao light-ion linear accelerator and neutron source has been completed and the normal conducting section of the linac is at present under construction. The machine has been designed to be compliant with ESS specifications following the international guidelines of such project as described in Ref. [1]. The new accelerator facility in Bilbao will serve as a base for support of activities on accelerator physics carried out in Spain and southern Europe in the frame of different ongoing international collaborations. Also, a number of applications have been envisaged in the new Bilbao facility for the outgoing light ion beams as well as from fast neutrons produced by low-energy neutron-capture targets, which are briefly described.

  6. High-energy in-beam neutron measurements of metal-based shielding for accelerator-driven spallation neutron sources

    Science.gov (United States)

    DiJulio, D. D.; Cooper-Jensen, C. P.; Björgvinsdóttir, H.; Kokai, Z.; Bentley, P. M.

    2016-05-01

    Metal-based shielding plays an important role in the attenuation of harmful and unwanted radiation at an accelerator-driven spallation neutron source. At the European Spallation Source, currently under construction in Lund, Sweden, metal-based materials are planned to be used extensively as neutron guide substrates in addition to other shielding structures around neutron guides. The usage of metal-based materials in the vicinity of neutron guides however requires careful consideration in order to minimize potential background effects in a neutron instrument at the facility. Therefore, we have carried out a combined study involving high-energy neutron measurements and Monte Carlo simulations of metal-based shielding, both to validate the simulation methodology and also to investigate the benefits and drawbacks of different metal-based solutions. The measurements were carried out at The Svedberg Laboratory in Uppsala, Sweden, using a 174.1 MeV neutron beam and various thicknesses of aluminum-, iron-, and copper-based shielding blocks. The results were compared to geant4 simulations and revealed excellent agreement. Our combined study highlights the particular situations where one type of metal-based solution may be preferred over another.

  7. Union of Compact Accelerator-Driven Neutron Sources (UCANS) I & II Neutron applications laboratory for ESS-Bilbao

    Science.gov (United States)

    Terrón, S.; Magán, M.; Sordo, F.; Ghiglino, A.; Mart«ınez, F.; Bermejo, F. J.; Perlado, J. M.

    The ESS-Bilbao Accelerator Center site at Lejoa UPV/EHU campus will be provided with a proton accelerator up to 300-400 MeV. In the first construction phase, a beam extraction will be set at the end of the DTL, which will produce a 50 MeV proton beam with an average current of 2.25 mA and 1.5 ms pulses at a frequency of 20 Hz. These beam characteristics allow to configure a low intensity neutron source based on Be (p, n) reactions, which enables experimentation with cold neutrons similar to that of LENS. The total beam power will be 112 kW, so the configuration of the neutron production target will be based on a rotating disk of beryllium slabs facing the beam on one side and a cryogenic methane moderator on the other, with the target-moderator system surrounded by a beryllium reflector. In this paper, first estimates will be presented for thermomechanical conditions of the target cooling scheme, neutron source intensities, and cold neutron pulses.

  8. Characterisation of an accelerator-based neutron source for BNCT of explanted livers

    Energy Technology Data Exchange (ETDEWEB)

    Agosteo, S. [Politecnico di Milano (Italy). Dipartimento di Ingeneria Nucleare; Colautti, P. [INFN, Padova (Italy). Laboratori Nazionali di Legnaro; Corrado, M.G. [Universita degli Studi di Milano (Italy). Dipartimento di Fisica; d`Errico, F. [Pisa Univ. (Italy). Dipt. di Costruzioni Meccaniche e Nucleari; Matzke, M. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Monti, S.; Tinti, R. [ENEA-ERG-FIRE, Bologna (Italy); Silari, M. [Consiglio Nazionale delle Ricerche, Milan (Italy)

    1997-09-01

    An accelerator-based thermal neutron source for BNCT of the explanted liver was designed using the MCNP code. Neutrons are generated via (d,n) reactions by 7 MeV deuterons bombarding a beryllium target. The therapy constraints were approached by simulating an irradiation cavity placed inside a graphite reflector parallelepiped containing a heavy-water moderator in turn enclosing the beryllium target. The experimental verification was performed at the Laboratori Nazionali di Legnaro (Italy). The thermal and epithermal neutron flux was measured at various positions in the irradiation cavity by means of activation techniques employing bare and cadmium covered indium foils. Further measurements were performed with BF{sub 3} detectors. The fast neutron component of the dose equivalent and the energy spectrum above 100keV were assessed by means of a recently developed technique employing variable threshold superheated drop detectors. The prompt gamma ray dose was measured with {sup 7}LiF TLDs. (author).

  9. Additive effect of BPA and Gd-DTPA for application in accelerator-based neutron source.

    Science.gov (United States)

    Yoshida, F; Yamamoto, T; Nakai, K; Zaboronok, A; Matsumura, A

    2015-12-01

    Because of its fast metabolism gadolinium as a commercial drug was not considered to be suitable for neutron capture therapy. We studied additive effect of gadolinium and boron co-administration using colony forming assay. As a result, the survival of tumor cells with additional 5 ppm of Gd-DTPA decreased to 1/10 compared to the cells with boron only. Using gadolinium to increase the effect of BNCT instead of additional X-ray irradiation might be beneficial, as such combination complies with the short-time irradiation regimen at the accelerator-based neutron source. PMID:26242560

  10. Status of spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-03-01

    Existing and planned facilities using proton accelerator driven spallation neutron source are reviewed. These include new project of neutron science proposed from Japan Atomic Energy Research Institute. The present status of facility requirement and accelerator technology leads us to new era of neutron science such as neutron scattering research and nuclear transmutation study using very intense neutron source. (author)

  11. 150 keV accelerator as pulsed neutron source; Acelerador de 150 keV como fuente de neutrones pulsada

    Energy Technology Data Exchange (ETDEWEB)

    Cordero, F.

    1970-07-01

    The project of a 150 keV Cockcroft-Walton accelerator built at J.E.N. is described. Beam currents of more than 10 mA, with a neutron intensity of 10{sup 1}1 n.s{sup 1}, are obtained. Also, we report some research made in connection with that project. The role of the contamination in the vacuum system and the performance of the pumps and gauges pumping deuterium gas are studied. Sinusoidal pulses are employed as an analysis method of the discharge in the ion source and the performance of the extracting-focusing system. The parameters of the beam leaving the ion source have been determined; these are used to calculate the electrostatic lenses with the gaussian optics. Measurements concerning deuterium and tritium targets as neutron sources have been made and the processes affecting their practical service life are analyzed. (Author) 71 refs.

  12. BRAHMMA: A compact experimental accelerator driven subcritical facility using D-T/D-D neutron source

    International Nuclear Information System (INIS)

    Highlights: • Design of compact zero-power subcritical assembly BRAHMMA is presented. • One of the unique features is the use of beryllium oxide as reflector. • Modular subcritical core which can be modified for different fuel combination. • Preliminary results of reactivity measurement using PNS technique reported. - Abstract: A zero-power, sub-critical assembly BRAHMMA driven by a D-T/D-D neutron generator has been designed and commissioned at Bhabha Atomic Research Centre, India. This facility has been conceived for investigating the static and dynamic neutronics properties of accelerator driven sub-critical systems. This paper describes the design details of the system. Preliminary results of flux measurements and reactivity measurements using pulsed neutron source techniques have also been presented. This system has the advantage of being modular in design which enables its keff values to be changed depending upon type of fuel being used and it is first in the series of subcritical assemblies being designed

  13. Intense Combined Source of Neutrons and Photons for Interrogation Based on Compact Deuteron RF Accelerator

    Science.gov (United States)

    Kurennoy, S. S.; Garnett, R. W.; Rybarcyk, L. J.

    Interrogation of special nuclear materials can benefit from mobile sources providing significant fluxes of neutrons (108/s at 2.5 MeV, 1010/s at 14.1 MeV) and of photons (>1012/s at 1-3 MeV). We propose a source that satisfies these requirements simultaneously plus also provides, via the reaction 11B(d,n)12C(γ15.1), a significant flux of 15-MeV photons, which are highly penetrating and optimal for inducing photo-fission in actinides. The source is based on a compact (< 5 m) deuteron RF accelerator that delivers an average current of a few mA of deuterons at 3-4 MeV to a boron target. The accelerator consists of a short RFQ followed by efficient inter-digital H-mode structures with permanent-magnet-quadrupole beam focusing [Kurennoy et al. (2012)], which suit perfectly for deuteron acceleration at low energies. Our estimates, based on recent measurements [Taddeucci et al. (2007)], indicate that the required fluxes of both neutrons and photons can be achieved at ∼1 mA of 4-MeV deuterons. The goal of the proposed study is to confirm feasibility of the approach and develop requirements for future full- system implementation.

  14. Conceptual study of a compact accelerator-driven neutron source for radioisotope production, boron neutron capture therapy and fast neutron therapy

    CERN Document Server

    Angelone, M; Rollet, S

    2002-01-01

    The feasibility of a compact accelerator-driven device for the generation of neutron spectra suitable for isotope production by neutron capture, boron neutron capture therapy and fast neutron therapy, is analyzed by Monte Carlo simulations. The device is essentially an extension of the activator proposed by Rubbia left bracket CERN/LHC/97-04(EET) right bracket , in which fast neutrons are diffused and moderated within a properly sized lead block. It is shown that by suitable design of the lead block, as well as of additional elements of moderating and shielding materials, one can generate and exploit neutron fluxes with the spectral features required for the above applications. The linear dimensions of the diffusing-moderating device can be limited to about 1 m. A full-scale device for all the above applications would require a fast neutron source of about 10**1**4 s**-**1, which could be produced by a 1 mA, 30 MeV proton beam impinging on a Be target. The concept could be tested at the Frascati Neutron Gener...

  15. Lithium antineutrino source in the tandem scheme of the accelerator and neutron producting tungsten target

    CERN Document Server

    Lyashuk, V I

    2016-01-01

    The antineutrinos of the neutron rich 8Li isotope is characterized by hard and good defined spectrum - averaged energy is 6.5 MeV and maximal - up to 13 MeV. An intensive antineutrino source with such parameters can be unique instrument for neutrino investigations and especially for search of sterile neutrinos. The 8Li can be produced by (n,gamma)-activation of 7Li isotope. The proposed scheme of the antineutrino source is based on the lithium blanket around the accelerator neutron producting target. We propose to use heavy water solution of the lithium hydroxide instead of lithium in metallic state. Such solution for lithium blanket substance ensure the large perspectives in real steps for creation of this installation. An analyses of neutron fields in the blanket and distribution of 8Li creation allows to propose the next principal steps in the construction of the lithium blanket. We propose to enclose the blanket volume isolating it's central part with more high 8Li production. This solution allows to decr...

  16. Intense pulsed neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Kustom, R.L.

    1981-01-01

    Accelerator requirements for pulsed spallation neutron sources are stated. Brief descriptions of the Argonne IPNS-I, the Japanese KENS, Los Alamos Scientific Laboratory WNR/PSR, the Rutherford Laboratory SNS, and the West German SNQ facilities are presented.

  17. ACCELERATOR SYSTEMS MODIFICATIONS FOR A SECOND TARGET STATION AT THE OAK RIDGE SPALLATION NEUTRON SOURCE

    Energy Technology Data Exchange (ETDEWEB)

    Galambos, John D [ORNL; Kim, Sang-Ho [ORNL; Plum, Michael A [ORNL

    2014-01-01

    A second target station is planned for the Oak Ridge Spallation Neutron Source. The ion source will be upgraded to increase the peak current from 38 to 49 mA, additional superconducting RF cavities will be added to the linac to increase the H beam energy from 938 to 1300 MeV, and the accumulator ring will receive modifications to the injection and extraction systems to accommodate the higher beam energy. After pulse compression in the storage ring one sixth of the beam pulses (10 out of 60 Hz) will be diverted to the second target by kicker and septum magnets added to the existing Ring to Target Beam Transport (RTBT) line. No further modifications will be made to the RTBT so that when the kicker and septum magnets are turned off the original beam transport lattice will be unaffected. In this paper we will discuss these and other planned modifications and upgrades to the accelerator facility.

  18. Spallation Neutron Source Accelerator Facility Target Safety and Non-safety Control Systems

    International Nuclear Information System (INIS)

    The Spallation Neutron Source (SNS) is a proton accelerator facility that generates neutrons for scientific researchers by spallation of neutrons from a mercury target. The SNS became operational on April 28, 2006, with first beam on target at approximately 200 W. The SNS accelerator, target, and conventional facilities controls are integrated by standardized hardware and software throughout the facility and were designed and fabricated to SNS conventions to ensure compatibility of systems with Experimental Physics Integrated Control System (EPICS). ControlLogix Programmable Logic Controllers (PLCs) interface to instruments and actuators, and EPICS performs the high-level integration of the PLCs such that all operator control can be accomplished from the Central Control room using EPICS graphical screens that pass process variables to and from the PLCs. Three active safety systems were designed to industry standards ISA S84.01 and IEEE 603 to meet the desired reliability for these safety systems. The safety systems protect facility workers and the environment from mercury vapor, mercury radiation, and proton beam radiation. The facility operators operated many of the systems prior to beam on target and developed the operating procedures. The safety and non-safety control systems were tested extensively prior to beam on target. This testing was crucial to identify wiring and software errors and failed components, the result of which was few problems during operation with beam on target. The SNS has continued beam on target since April to increase beam power, check out the scientific instruments, and continue testing the operation of facility subsystems

  19. Pulsed spallation neutron source with an induction LINAC and a fixed-field alternating-gradient accelerator

    International Nuclear Information System (INIS)

    The paper describes an accelerator scenario of a Pulsed Spallation Neutron Source made of an Induction Linac injecting into a Fixed-Field Alternating-Gradient Accelerator (FFAG). The motivations underlying the proposal deal with the concern of removing technical risks peculiar to other scenarios involving RF Linacs, Synchrotrons and Accumulator Rings, which originate, for example, from the need of developing intense negative-ion sources and of multi-turn injection into the Compressor Rings. The system proposed here makes use of a positive-ion source of very short pulse duration, and of single-turn transfer into the circular accelerator. (author) 2 figs., 2 tabs., 16 refs

  20. Laser-driven x-ray and neutron source development for industrial applications of plasma accelerators

    Science.gov (United States)

    Brenner, C. M.; Mirfayzi, S. R.; Rusby, D. R.; Armstrong, C.; Alejo, A.; Wilson, L. A.; Clarke, R.; Ahmed, H.; Butler, N. M. H.; Haddock, D.; Higginson, A.; McClymont, A.; Murphy, C.; Notley, M.; Oliver, P.; Allott, R.; Hernandez-Gomez, C.; Kar, S.; McKenna, P.; Neely, D.

    2016-01-01

    Pulsed beams of energetic x-rays and neutrons from intense laser interactions with solid foils are promising for applications where bright, small emission area sources, capable of multi-modal delivery are ideal. Possible end users of laser-driven multi-modal sources are those requiring advanced non-destructive inspection techniques in industry sectors of high value commerce such as aerospace, nuclear and advanced manufacturing. We report on experimental work that demonstrates multi-modal operation of high power laser-solid interactions for neutron and x-ray beam generation. Measurements and Monte Carlo radiation transport simulations show that neutron yield is increased by a factor ~2 when a 1 mm copper foil is placed behind a 2 mm lithium foil, compared to using a 2 cm block of lithium only. We explore x-ray generation with a 10 picosecond drive pulse in order to tailor the spectral content for radiography with medium density alloy metals. The impact of using  >1 ps pulse duration on laser-accelerated electron beam generation and transport is discussed alongside the optimisation of subsequent bremsstrahlung emission in thin, high atomic number target foils. X-ray spectra are deconvolved from spectrometer measurements and simulation data generated using the GEANT4 Monte Carlo code. We also demonstrate the unique capability of laser-driven x-rays in being able to deliver single pulse high spatial resolution projection imaging of thick metallic objects. Active detector radiographic imaging of industrially relevant sample objects with a 10 ps drive pulse is presented for the first time, demonstrating that features of 200 μm size are resolved when projected at high magnification.

  1. Neutrons from medical electron accelerators

    International Nuclear Information System (INIS)

    The significant sources of photoneutrons within a linear-accelerator treatment head are identified and absolute estimates of neutron production per treatment dose are given for typical components. Measured data obtained at a variety of accelerator installations are presented and compared with these calculations. It is found that the high-Z materials within the treatment head do not significantly alter the neutron fluence, but do substantially reduce the average energy of the transmitted spectrum. Reflected neutrons from the concrete treatment room contribute to the neutron fluence, but not substantially to the patient integral dose, because of a further reduction in average energy. Absolute depth-dose distributions for realistic neutron spectra are calculated, and a rapid falloff with depth is found

  2. Study of medical RI production with accelerator-based neutron sources

    International Nuclear Information System (INIS)

    The single-photon emission computed tomography (SPECT) and positron emission tomography (PET) have been widely adopted for nuclear medicine imaging to make diagnoses of body functions, identification of site of cancers, and so on. Now, almost all of medical radio isotopes are produced by nuclear reactors or charged particle accelerators. We propose a new route to produce the medical radio isotopes with accelerator-based neutron sources. In this paper, as an example, we introduce the proposed production method of 99Mo, which is the mother nuclide of 99mTc for SPECT. We determined the 100Mo(n,2n)99Mo reaction cross section to 1,415±82mb and it was consistent with the value (1,398mb) obtained from JENDL-4.0. Therefore, it indicates yields of produced RIs can be predicted with nuclear data based simulations. The simulation also can be used to design irradiation condition. In this paper some results of the simulations are also shown. (author)

  3. NIFTI and DISCOS: New concepts for a compact accelerator neutron source for boron neutron capture therapy applications

    International Nuclear Information System (INIS)

    Two new concepts, NIFTI and DISCOS, are described. These concepts enable the efficient production of epithermal neutrons for BNCT (Boron Neutron Capture Therapy) medical treatment, utilizing a low current, low energy proton beam impacting on a lithium target. The NIFTI concept uses fluoride compounds, such as lead or beryllium fluoride, to efficiently degrade high energy neutrons from the lithium target to the lower energies required for BNCT. The fluoride compounds are in turn encased in an iron layer that strongly impedes the transmission of neutrons with energies above 24 KeV. Lower energy neutrons readily pass through this iron filter, which has a deep window in its scattering cross section at 24 KeV. The DISCOS concept uses a rapidly rotating, high g disc to create a series of thin (∼ 1 micron thickness) liquid lithium targets in the form of continuous films or sheets of discrete droplets--through which the proton beam passes. The average energy lost by a proton as it passes through a single target is small, approximately 10 KeV. Between the targets, the proton beam is re-accelerated by an applied DC electric field. The DISCOS approach enables the accelerator--target facility to operate with a beam energy only slightly above the threshold value for neutron production--resulting in an output beam of low-energy epithermal neutrons--while achieving a high yield of neutrons per milliamp of proton beam current. Parametric trade studies of the NIFTI and DISCOS concepts are described. These include analyses of a broad range of NIFTI designs using the Monte carlo MCNP neutronics code, as well as mechanical and thermal-hydraulic analyses of various DISCOS designs

  4. International panel on 14 MeV intense neutron source based on accelerators for fusion material study

    International Nuclear Information System (INIS)

    The International Panel on 14 MeV Intense Neutron Source Based on Accelerators for Fusion Materials Study was held January 14--16, 1991, at the Department of Nuclear Engineering, the University of Tokyo. The panel was attended by 38 participants, including 9 from the US, 3 from the EC, and 1 from Canada. This meeting had initially been planned as a bilateral US-Japan workshop, but was expanded to international participation in response to the recently issued FPAC report in the US and the FPEB report in the EC. Both of these documents proposed schedules for the DEMO fusion reactor that present a challenge for the materials community, and restated the importance of the required materials development and the necessity of an international 14 MeV neutron source for the development of the magnetic fusion energy option. The scope of the panel was restricted to source concepts judged to be practical within the next five years little further development. The goals of the panel were to reach a consensus on a practical approach, to collect information on accelerator based concepts, to list critical issues, and to produce tentative schedules for design and development of a neutron source. Most of the panel presentations and discussions were on the d-Li approach to neutron source. The status of the FMI project at its termination and the advance in accelerator technology and target concepts since the time were summarized. No feasibility questions remaining with this approach were seen, but high power beam-on-target verification tests and demonstration of accelerator performance limits remain to be accomplished

  5. Nuclear energy generation and waste transmutation using an accelerator-driven intense thermal neutron source

    International Nuclear Information System (INIS)

    We describe a new approach for commercial nuclear energy production without a long-term high-level waste stream and for transmutation of both fission product and higher actinide commercial nuclear waste using a thermal flux of accelerator-produced neutrons in the 1016 n/cm2-s range. Continuous neutron fluxes at this intensity, which is approximately 100 times larger than is typically available in a large scale thermal reactor, appear practical owing to recent advances in proton linear accelerator technology and to the spallation target-moderator design presented here. This large flux of thermal neutrons makes possible a waste inventory in the transmutation system which is smaller by about a factor of 100 than competing concepts. The accelerator allows the system to operate well below criticality so that the possibility for a criticality accident is estimated. No control rods are required. The successful implementation of this new method for energy generation and waste transmutation would eliminate the need for nuclear waste storage on a geologic time scale. The production of nuclear energy from 232Th or 238U is used to illustrate the general principles of commercial nuclear energy production without long-term high-level waste. There is sufficient thorium to meet the world's energy needs for many millenia. 27 refs., 13 figs., 12 tabs

  6. Laser-driven x-ray and neutron source development for industrial applications of plasma accelerators

    OpenAIRE

    Brenner, C.M.; Mirfayzi, S. R.; Rusby, D. R.; Armstrong, C; Alejo, A.; Wilson, L A; Clarke, R; Ahmed, H.; Butler, N. M H; Haddock, D; Higginson, A; McClymont, A.; Murphy, C; Notley, M.; Oliver, P

    2015-01-01

    Pulsed beams of energetic x-rays and neutrons from intense laser interactions with solid foils are promising for applications where bright, small emission area sources, capable of multi-modal delivery are ideal. Possible end users of laser-driven multi-modal sources are those requiring advanced non-destructive inspection techniques in industry sectors of high value commerce such as aerospace, nuclear and advanced manufacturing. We report on experimental work that demonstrates multi-modal oper...

  7. Basic design of shield blocks for a spallation neutron source under the high-intensity proton accelerator project

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Katsuhiko; Maekawa, Fujio; Takada, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    Under the JAERI-KEK High-Intensity Proton Accelerator Project (J-PARC), a spallation neutron source driven by a 3 GeV-1 MW proton beam is planed to be constructed as a main part of the Materials and Life Science Facility. Overall dimensions of a biological shield of the neutron source had been determined by evaluation of shielding performance by Monte Carlo calculations. This report describes results of design studies on an optimum dividing scheme in terms of cost and treatment and mechanical strength of shield blocks for the biological shield. As for mechanical strength, it was studied whether the shield blocks would be stable, fall down or move to a horizontal direction in case of an earthquake of seismic intensity of 5.5 (250 Gal) as an abnormal load. For ceiling shielding blocks being supported by both ends of the long blocks, maximum bending moment and an amount of maximum deflection of their center were evaluated. (author)

  8. A neutron booster for spallation sources--application to accelerator driven systems and isotope production

    CERN Document Server

    Galy, J; Van Dam, H; Valko, J

    2002-01-01

    One can design a critical system with fissile material in the form of a thin layer on the inner surface of a cylindrical neutron moderator such as graphite or beryllium. Recently, we have investigated the properties of critical and near critical systems based on the use of thin actinide layers of uranium, plutonium and americium. The thickness of the required fissile layer depends on the type of fissile material, its concentration in the layer and on the geometrical arrangement, but is typically in the mu m-mm range. The resulting total mass of fissile material can be as low as 100 g. Thin fissile layers have a variety of applications in nuclear technology--for example in the design neutron amplifiers for medical applications and 'fast' islands in thermal reactors for waste incineration. In the present paper, we investigate the properties of a neutron booster unit for spallation sources and isotope production. In those applications a layer of fissile material surrounds the spallation source. Such a module cou...

  9. Accelerator system for neutron radiography

    International Nuclear Information System (INIS)

    The field of x-ray radiography is well established for doing non-destructive evaluation of a vast array of components, assemblies, and objects. While x-rays excel in many radiography applications, their effectiveness diminishes rapidly if the objects of interest are surrounded by thick, high-density materials that strongly attenuate photons. Due to the differences in interaction mechanisms, neutron radiography is highly effective in imaging details inside such objects. To obtain a high intensity neutron source suitable for neutron imaging a 9-MeV linear accelerator is being evaluated for putting a deuteron beam into a high-pressure deuterium gas cell. As a windowless aperture is needed to transport the beam into the gas cell, a low-emittance is needed to minimize losses along the high-energy beam transport (HEBT) and the end station. A description of the HEBT, the transport optics into the gas cell, and the requirements for the linac will be presented

  10. Pulsed neutron sources for epithermal neutrons

    International Nuclear Information System (INIS)

    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

  11. Spallation Neutron Source (SNS)

    Data.gov (United States)

    Federal Laboratory Consortium — The SNS at Oak Ridge National Laboratory is a next-generation spallation neutron source for neutron scattering that is currently the most powerful neutron source in...

  12. Final Report US-Japan IEC Workshop on Small Plasma and Accelerator Neutron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Miley, George, H.

    2008-06-04

    Abstract The history of IEC development will be briefly described, and some speculation about future directions will be offered. The origin of IEC is due to the brilliance of Phil Farnsworth, inventor of electronic TV in the US. Early experiments were pioneered in the late 1960s by Robert Hirsch who later became head of the DOE fusion program. At that time studies of IEC physics quickly followed at the University of Illinois and at Penn State University. However, despite many successes in this early work, IEC research died as DOE funding stopped in the mid 1980s. In the early 90’s, R. W. Bussard of EMC revived work with a new major project based on a magnetic assisted IEC. While doing supportive studies for that project, G. Miley proposed a grided “STAR mode” IEC as a neutron source for NAA. This concept was later used commercially by Daimler- Benz in Germany to analysis impurities in incoming ores. This represented a first practical application of the IEC. During this period other research groups at LANL, U of Wisconsin and Kyoto University entered IEC research with innovative new concepts and approaches to IEC physics and applications. Much of this work is documented in the present and in past US-Japan Workshops. At present we stand on the threshold of a new area of IEC applications as neutron source, for isotope production, and as a plasma source. These applications provide a way to continue IEC understanding and technology development with the ultimate goal being a fusion power plant. Indeed, a distinguishing feature of the IEC vs. other fusion confinement approaches is the unique opportunity for “spin off” applications along the way to a power producing plant.

  13. US-Japan IEC Workshop on Small Plasma and Accelerator Neutron Sources. Final report

    International Nuclear Information System (INIS)

    The history of IEC development will be briefly described, and some speculation about future directions will be offered. The origin of IEC is due to the brilliance of Phil Farnsworth, inventor of electronic TV in the US. Early experiments were pioneered in the late 1960s by Robert Hirsch who later became head of the DOE fusion program. At that time studies of IEC physics quickly followed at the University of Illinois and at Penn State University. However, despite many successes in this early work, IEC research died as DOE funding stopped in the mid 1980s. In the early 90's, R. W. Bussard of EMC revived work with a new major project based on a magnetic assisted IEC. While doing supportive studies for that project, G. Miley proposed a grided 'STAR mode' IEC as a neutron source for NAA. This concept was later used commercially by Daimler-Benz in Germany to analysis impurities in incoming ores. This represented a first practical application of the IEC. During this period other research groups at LANL, U of Wisconsin and Kyoto University entered IEC research with innovative new concepts and approaches to IEC physics and applications. Much of this work is documented in the present and in past US-Japan Workshops. At present we stand on the threshold of a new area of IEC applications as neutron source, for isotope production, and as a plasma source. These applications provide a way to continue IEC understanding and technology development with the ultimate goal being a fusion power plant. Indeed, a distinguishing feature of the IEC vs. other fusion confinement approaches is the unique opportunity for 'spin off' applications along the way to a power producing plant.

  14. Neutron scattering and spallation neutron sources

    International Nuclear Information System (INIS)

    Neutron scattering as a probe of microscopic structure and dynamics is a powerful tool for research in a wide variety of fields, and an accelerator-based spallation neutron source can supply high flux pulses for neutron scattering. The characteristics of neutron scattering, the principle and development of spallation neutron sources, and their advantages in multidisciplinary applications are summarized. In the proposed project of the Chinese Spallation Neutron Source the target station will consist of a piece-stacked tungsten target, a Be/Fe reflector and an Fe/heavy concrete bio-protected shelter. The pulsed neutron flux will be up to 2.4 x 1016 n/cm2/s under a nuclear power of 100 kW. Five neutron scattering instruments--a high flux powder diffractometer, a high resolution powder diffractometer, small angle diffractometer, multi-functional reflectometer and direct geometry inelastic spectrometer, will be constructed as the first step to cover most neutron scattering applications. (authors)

  15. 3-dimensional shielding design for a spallation neutron source facility in the high-intensity proton accelerator project

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, Masaya; Maekawa, Fujio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    Evaluation of shielding performance for a 1 MW spallation neutron source facility in the Materials and Life Science Facility being constructed in the High-Intensity Proton Accelerator Project (J-PARC) is important from a viewpoint of radiation safety and optimization of arrangement of components. This report describes evaluated results for the shielding performance with modeling three-dimensionally whole structural components including gaps between them in detail. A Monte Carlo calculation method with MCNPX2.2.6 code and LA-150 library was adopted. Streaming and void effects, optimization of shield for cost reduction and optimization of arrangement of structures such as shutters were investigated. The streaming effects were investigated quantitatively by changing the detailed structure of components and gap widths built into the calculation model. Horizontal required shield thicknesses were ranged from about 6.5 m to 7.5 m as a function of neutron beam line angles. A shutter mechanism for a horizontal neutron reflectometer that was directed downward was devised, and it was shown that the shielding performance of the shutter was acceptable. An optimal biological shield configuration was finally determined according to the calculated results. (author)

  16. Optimal moderator materials at various proton energies considering photon dose rate after irradiation for an accelerator-driven ⁹Be(p, n) boron neutron capture therapy neutron source.

    Science.gov (United States)

    Hashimoto, Y; Hiraga, F; Kiyanagi, Y

    2015-12-01

    We evaluated the accelerator beam power and the neutron-induced radioactivity of (9)Be(p, n) boron neutron capture therapy (BNCT) neutron sources having a MgF2, CaF2, or AlF3 moderator and driven by protons with energy from 8 MeV to 30 MeV. The optimal moderator materials were found to be MgF2 for proton energies less than 10 MeV because of lower required accelerator beam power and CaF2 for higher proton energies because of lower photon dose rate at the treatment position after neutron irradiation.

  17. PRODUCTION AND APPLICATIONS OF NEUTRONS USING PARTICLE ACCELERATORS

    Energy Technology Data Exchange (ETDEWEB)

    David L. Chichester

    2009-11-01

    Advances in neutron science have gone hand in hand with the development and of particle accelerators from the beginning of both fields of study. Early accelerator systems were developed simply to produce neutrons, allowing scientists to study their properties and how neutrons interact in matter, but people quickly realized that more tangible uses existed too. Today the diversity of applications for industrial accelerator-based neutron sources is high and so to is the actual number of instruments in daily use is high, and they serve important roles in the fields where they're used. This chapter presents a technical introduction to the different ways particle accelerators are used to produce neutrons, an historical overview of the early development of neutron-producing particle accelerators, a description of some current industrial accelerator systems, narratives of the fields where neutron-producing particle accelerators are used today, and comments on future trends in the industrial uses of neutron producing particle accelerators.

  18. Accelerator-based neutron source using a cold deuterium target with degenerate electrons

    Directory of Open Access Journals (Sweden)

    R. E. Phillips

    2013-07-01

    Full Text Available A neutron generator is considered in which a beam of tritons is incident on a hypothetical cold deuterium target with degenerate electrons. The energy efficiency of neutron generation is found to increase substantially with electron density. Recent reports of potential targets are discussed.

  19. Development of high intensity ion sources for a Tandem-Electrostatic-Quadrupole facility for Accelerator-Based Boron Neutron Capture Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Bergueiro, J. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)] [CONICET, Buenos Aires (Argentina); Igarzabal, M.; Suarez Sandin, J.C. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina); Somacal, H.R. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)] [Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin (Argentina); Thatar Vento, V. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)] [CONICET, Buenos Aires (Argentina); Huck, H.; Valda, A.A. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)] [Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin (Argentina); Repetto, M. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)

    2011-12-15

    Several ion sources have been developed and an ion source test stand has been mounted for the first stage of a Tandem-Electrostatic-Quadrupole facility For Accelerator-Based Boron Neutron Capture Therapy. A first source, designed, fabricated and tested is a dual chamber, filament driven and magnetically compressed volume plasma proton ion source. A 4 mA beam has been accelerated and transported into the suppressed Faraday cup. Extensive simulations of the sources have been performed using both 2D and 3D self-consistent codes.

  20. Properties of neutron sources

    International Nuclear Information System (INIS)

    The Conference presentations were divided into sessions devoted to the following topics: white neutron sources, primarily pulsed (6 papers); fast neutron fields (5 papers); Californium-252 prompt fission neutron spectra (14 papers); monoenergetic sources and filtered beams (11 papers); 14 MeV neutron sources (10 papers); selected special application (one paper); and a general interest session (4 papers). Individual abstracts were prepared separately for the papers

  1. Vacuum seals design and testing for a linear accelerator of the National Spallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Z. Chen; C. Gautier; F. Hemez; N. K. Bultman

    2000-02-01

    Vacuum seals are very important to ensure that the Spallation Neutron Source (SNS) Linac has an optimum vacuum system. The vacuum joints between flanges must have reliable seals to minimize the leak rate and meet vacuum and electrical requirements. In addition, it is desirable to simplify the installation and thereby also simplify the maintenance required. This report summarizes an investigation of the metal vacuum seals that include the metal C-seal, Energized Spring seal, Helcoflex Copper Delta seal, Aluminum Delta seal, delta seal with limiting ring, and the prototype of the copper diamond seals. The report also contains the material certifications, design, finite element analysis, and testing for all of these seals. It is a valuable reference for any vacuum system design. To evaluate the suitability of several types of metal seals for use in the SNS Linac and to determine the torque applied on the bolts, a series of vacuum leak rate tests on the metal seals have been completed at Los Alamos Laboratory. A copper plated flange, using the same type of delta seal that was used for testing with the stainless steel flange, has also been studied and tested. A vacuum seal is desired that requires significantly less loading than a standard ConFlat flange with a copper gasket for the coupling cavity assembly. To save the intersegment space the authors use thinner flanges in the design. The leak rate of the thin ConFlat flange with a copper gasket is a baseline for the vacuum test on all seals and thin flanges. A finite element analysis of a long coupling cavity flange with a copper delta seal has been performed in order to confirm the design of the long coupling cavity flange and the welded area of a cavity body with the flange. This analysis is also necessary to predict a potential deformation of the cavity under the combined force of atmospheric pressure and the seating load of the seal. Modeling of this assembly has been achieved using both HKS/Abaqus and COSMOS

  2. Vacuum seals design and testing for a linear accelerator of the National Spallation Neutron Source

    International Nuclear Information System (INIS)

    Vacuum seals are very important to ensure that the Spallation Neutron Source (SNS) Linac has an optimum vacuum system. The vacuum joints between flanges must have reliable seals to minimize the leak rate and meet vacuum and electrical requirements. In addition, it is desirable to simplify the installation and thereby also simplify the maintenance required. This report summarizes an investigation of the metal vacuum seals that include the metal C-seal, Energized Spring seal, Helcoflex Copper Delta seal, Aluminum Delta seal, delta seal with limiting ring, and the prototype of the copper diamond seals. The report also contains the material certifications, design, finite element analysis, and testing for all of these seals. It is a valuable reference for any vacuum system design. To evaluate the suitability of several types of metal seals for use in the SNS Linac and to determine the torque applied on the bolts, a series of vacuum leak rate tests on the metal seals have been completed at Los Alamos Laboratory. A copper plated flange, using the same type of delta seal that was used for testing with the stainless steel flange, has also been studied and tested. A vacuum seal is desired that requires significantly less loading than a standard ConFlat flange with a copper gasket for the coupling cavity assembly. To save the intersegment space the authors use thinner flanges in the design. The leak rate of the thin ConFlat flange with a copper gasket is a baseline for the vacuum test on all seals and thin flanges. A finite element analysis of a long coupling cavity flange with a copper delta seal has been performed in order to confirm the design of the long coupling cavity flange and the welded area of a cavity body with the flange. This analysis is also necessary to predict a potential deformation of the cavity under the combined force of atmospheric pressure and the seating load of the seal. Modeling of this assembly has been achieved using both HKS/Abaqus and COSMOS

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

    CERN Document Server

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

    2003-01-01

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

  4. Neutron sources and applications

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-01-01

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

  5. Neutron sources and applications

    International Nuclear Information System (INIS)

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

  6. Outline of spallation neutron source engineering

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Noboru [Center for Neutron Science, Tokai Research Establishment, Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan)

    2001-01-01

    Slow neutrons such as cold and thermal neutrons are unique probes which can determine structures and dynamics of condensed matter in atomic scale. The neutron scattering technique is indispensable not only for basic sciences such as condensed matter research and life science, but also for basic industrial technology in 21 century. It is believed that to survive in the science-technology competition in 21 century would be almost impossible without neutron scattering. However, the intensity of neutrons presently available is much lower than synchrotron radiation sources, etc. Thus, R and D of intense neutron sources become most important. The High-Intensity Proton Accelerator Project is now being promoted jointly by Japan Atomic Energy Research Institute and High Energy Accelerator Research Organization, but there has so far been no good text which covers all the aspects of pulsed spallation neutron sources. The present review was prepare aiming at giving a better understanding on pulsed spallation neutron sources not only to neutron source researchers but also more widely to neutron scattering researchers and accelerator scientists in this field. The contents involve, starting from what is neutron scattering and what neutrons are necessary for neutron scattering, what is the spallation reaction, how to produce neutrons required for neutron scattering more efficiently, target-moderator-reflector neutronics and its engineering, shielding, target station, material issues, etc. The author have engaged in R and D of pulsed apallation neutron sources and neutron scattering research using them over 30 years. The present review is prepared based on the author's experiences with useful information obtained through ICANS collaboration and recent data from the JSNS (Japanese Spallation Neutron Source) design team. (author)

  7. Pulsed spallation Neutron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, J.M. [Argonne National Lab., IL (United States)

    1994-12-31

    This paper reviews the early history of pulsed spallation neutron source development at Argonne and provides an overview of existing sources world wide. A number of proposals for machines more powerful than currently exist are under development, which are briefly described. The author reviews the status of the Intense Pulsed Neutron Source, its instrumentation, and its user program, and provides a few examples of applications in fundamental condensed matter physics, materials science and technology.

  8. THERMAL NEUTRON INTENSITIES IN SOILS IRRADIATED BY FAST NEUTRONS FROM POINT SOURCES. (R825549C054)

    Science.gov (United States)

    Thermal-neutron fluences in soil are reported for selected fast-neutron sources, selected soil types, and selected irradiation geometries. Sources include 14 MeV neutrons from accelerators, neutrons from spontaneously fissioning 252Cf, and neutrons produced from alp...

  9. Compact ion source neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Schenkel, Thomas; Persaud, Arun; Kapadia, Rehan; Javey, Ali; Chang-Hasnain, Constance; Rangelow, Ivo; Kwan, Joe

    2015-10-13

    A neutron generator includes a conductive substrate comprising a plurality of conductive nanostructures with free-standing tips and a source of an atomic species to introduce the atomic species in proximity to the free-standing tips. A target placed apart from the substrate is voltage biased relative to the substrate to ionize and accelerate the ionized atomic species toward the target. The target includes an element capable of a nuclear fusion reaction with the ionized atomic species to produce a one or more neutrons as a reaction by-product.

  10. Basic concept for an accelerator-driven subcritical system to be used as a long-pulse neutron source for Condensed Matter research

    Energy Technology Data Exchange (ETDEWEB)

    Vivanco, R., E-mail: raul.vivanco.sanchez@gmail.com [ESS-BILBAO, Parque Tecnológico Bizkaia, Laida Bidea, Edificio 207 B Planta Baja, 48160 Derio (Spain); Instituto de Fusión Nuclear - UPM, ETS Ingenieros Industriales, C/ José Gutiérrez Abascal, 2, 28006 Madrid Spain (Spain); Ghiglino, A.; Vicente, J.P. de; Sordo, F.; Terrón, S.; Magán, M. [ESS-BILBAO, Parque Tecnológico Bizkaia, Laida Bidea, Edificio 207 B Planta Baja, 48160 Derio (Spain); Instituto de Fusión Nuclear - UPM, ETS Ingenieros Industriales, C/ José Gutiérrez Abascal, 2, 28006 Madrid Spain (Spain); Perlado, J.M. [Instituto de Fusión Nuclear - UPM, ETS Ingenieros Industriales, C/ José Gutiérrez Abascal, 2, 28006 Madrid Spain (Spain); Bermejo, F.J. [Instituto de Estructura de la Materia, IEM-CSIC, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid (Spain)

    2014-12-11

    A model for an accelerator-driven subcritical system to be operated as a source of cold neutrons for Condensed Matter research is developed at the conceptual level. Its baseline layout relies upon proven accelerator, spalattion target and fuel array technologies, and consists in a proton accelerator able to deliver some 67.5 mA of proton beam with kinetic energy 0.6 GeV, a pulse length of 2.86 ms, and repetition rate of 14 Hz. The particle beam hits a target of conventional design that is surrounded by a multiplicative core made of fissile/fertile material, composed by a subcritical array of fuel bars made of aluminium Cermet cooled by light water poisoned with boric acid. Relatively low enriched uranium is chosen as fissile material. An optimisation of several parameters is carried out, using as components of the objective function several characteristics pertaining the cold neutron pulse. The results show that the optimal device will deliver up to 80% of the cold neutron flux expected for some of the ongoing projects using a significantly lower proton beam power than that managed in such projects. The total power developed within the core rises up to 22.8 MW, and the criticality range shifts to a final k{sub eff} value of around 0.9 after the 50 days cycle.

  11. Spectrum shaping of accelerator-based neutron beams for BNCT

    CERN Document Server

    Montagnini, B; Esposito, J; Giusti, V; Mattioda, F; Varone, R

    2002-01-01

    We describe Monte Carlo simulations of three facilities for the production of epithermal neutrons for Boron Neutron Capture Therapy (BNCT) and examine general aspects and problems of designing the spectrum-shaping assemblies to be used with these neutron sources. The first facility is based on an accelerator-driven low-power subcritical reactor, operating as a neutron amplifier. The other two facilities have no amplifier and rely entirely on their primary sources, a D-T fusion reaction device and a conventional 2.5 MeV proton accelerator with a Li target, respectively.

  12. Californium-252 neutron sources

    International Nuclear Information System (INIS)

    Major production programs for the Savannah River reactors and the High Flux Isotopes Reactor at Oak Ridge have made 252Cf one of the most available and, at the USAEC's sales price of $10/μg, one of the least-expensive isotopic neutron sources. Reactor production has totaled approximately 2 g, and, based on expected demand, an additional 10 g will be produced in the next decade. The approximately 800 mg chemically separated to date has been used to prepare over 600 neutron sources. Most, about 500, have been medical sources containing 1 to 5 μg of 252Cf plated in needles for experimental cancer therapy studies. The remainder have generally been point sources containing 10 μg to 12 mg of oxide for activation, well logging, or radiography uses. Bulk sources have also been supplied to the commercial encapsulators. The latest development has been the production of 252Cf cermet wire which can be cut into almost contamination-free lengths of the desired 252Cf content. Casks are available for transport of sources up to 50 mg. Subcritical assemblies have been developed to multiply the source neutrons by a factor of 10 to 40, and collimators and thermalizers have also been extensively developed to shape the neutron flux and energy distributions for special applications. (U.S.)

  13. Plasma focus neutron source

    International Nuclear Information System (INIS)

    A neutron source not permanently active is obtained from an electric discharge plasma focus (PF) device. A small PF device, a Mather model device, works in the limit of low energy, 100 to 200 J at charging voltage of 20 to 30 kV with a capacitor bank of 160 nF, and a characteristic inductance of 25 to 50 nH. A theoretical model leads us to estimate the optimum values of capacitance, inductance, initial charging voltage and electrode geometry. In this work is presented the design evolution and construction of a first PF neutron source prototype, preliminary measures of current, voltage and temporal evolution of the current with the end of have an electric characterization. This parameters must be optimized with the objective of geeting an emission of 104 to 105 neutrons per pulse when Deuterium is used like filled gas (C.W)

  14. New sources and instrumentation for neutron science

    Science.gov (United States)

    Gil, Alina

    2011-04-01

    Neutron-scattering research has a lot to do with our everyday lives. Things like medicine, food, electronics, cars and airplanes have all been improved by neutron-scattering research. Neutron research also helps scientists improve materials used in a multitude of different products, such as high-temperature superconductors, powerful lightweight magnets, stronger, lighter plastic products etc. Neutron scattering is one of the most effective ways to obtain information on both, the structure and the dynamics of condensed matter. Most of the world's neutron sources were built decades ago, and although the uses and demand for neutrons have increased throughout the years, few new sources have been built. The new construction, accelerator-based neutron source, the spallation source will provide the most intense pulsed neutron beams in the world for scientific research and industrial development. In this paper it will be described what neutrons are and what unique properties make them useful for science, how spallation source is designed to produce neutron beams and the experimental instruments that will use those beams. Finally, it will be described how past neutron research has affected our everyday lives and what we might expect from the most exciting future applications.

  15. SUPERCONDUCTING LINAC FOR THE SPALLATION NEUTRON SOURCE

    International Nuclear Information System (INIS)

    The Spallation Neutron Source (SNS) linac is comprised of both normal and superconducting rf (SRF) accelerating structures. The SRF linac accelerates the beam from 186 to 1250 MeV through 117 elliptical, multi-cell niobium cavities. This paper describes the SRF linac architecture, physics design considerations, cavity commissioning, and the expected beam dynamics performance

  16. Neutron source for Neutron Capture Synovectomy

    International Nuclear Information System (INIS)

    Monte Carlo calculations were performed to obtain a thermal neutron field from a 239PuBe neutron source inside a cylindrical heterogeneous moderators for Neutron Capture Synovectomy. Studied moderators were light water and heavy water, graphite and heavy water, lucite and polyethylene and heavy water. The neutron spectrum of polyethylene and heavy water moderator was used to determine neutron spectra inside a knee model. In this model the elemental composition of synovium and synovial liquid was assumed like blood. Kerma factors for synovium and synovial liquid were calculated to compare with water Kerma factors, in this calculations the synovium was loaded with two different concentrations of Boron

  17. Future opportunities with pulsed neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, A.D. [Rutherford Appleton Lab., Chilton (United Kingdom)

    1996-05-01

    ISIS is the world`s most powerful pulsed spallation source and in the past ten years has demonstrated the scientific potential of accelerator-driven pulsed neutron sources in fields as diverse as physics, earth sciences, chemistry, materials science, engineering and biology. The Japan Hadron Project gives the opportunity to build on this development and to further realize the potential of neutrons as a microscopic probe of the condensed state. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z. (Zukun)

    2001-01-01

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

  19. Cyclotron-based neutron source for BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K. [Sumitomo Heavy Industries, Ltd (Japan); Tanaka, H.; Sakurai, Y.; Maruhashi, A. [Kyoto University Research Reactor Institute (Japan)

    2013-04-19

    Kyoto University Research Reactor Institute (KURRI) and Sumitomo Heavy Industries, Ltd. (SHI) have developed a cyclotron-based neutron source for Boron Neutron Capture Therapy (BNCT). It was installed at KURRI in Osaka prefecture. The neutron source consists of a proton cyclotron named HM-30, a beam transport system and an irradiation and treatment system. In the cyclotron, H- ions are accelerated and extracted as 30 MeV proton beams of 1 mA. The proton beams is transported to the neutron production target made by a beryllium plate. Emitted neutrons are moderated by lead, iron, aluminum and calcium fluoride. The aperture diameter of neutron collimator is in the range from 100 mm to 250 mm. The peak neutron flux in the water phantom is 1.8 Multiplication-Sign 109 neutrons/cm{sup 2}/sec at 20 mm from the surface at 1 mA proton beam. The neutron source have been stably operated for 3 years with 30 kW proton beam. Various pre-clinical tests including animal tests have been done by using the cyclotron-based neutron source with {sup 10}B-p-Borono-phenylalanine. Clinical trials of malignant brain tumors will be started in this year.

  20. Destructive analysis of neutron sources

    International Nuclear Information System (INIS)

    Fuel-liner reactions in Pu--Be neutron sources were examined. The source is contained in an outer jacket of 304 stainless steel and an inner Ta container incorporating a TIG welded Ta plug. Small cracks were observed in some of the outer stainless steel containers as well as in some of the tantalum inner liners. Major cracking was observed as well as penetration of the reaction product through the tantalum sidewalls in two sources. High temperatures aided and accelerated the degradation and ultimate failure of the tantalum inner liner. Traces of beryllium metal as indicated from x-ray results of the fuel and large concentration gradients between tantalum and plutonium as shown in microprobe analysis were found to exist. The fuel was inhomogeneous in nature and the data suggest the possibility of tantalum-beryllium compounds, free unreacted plutonium, and potentially a ternary phase of tantalum, beryllium, plutonium as being present in the fuel

  1. Isotopic neutron sources for neutron activation analysis

    International Nuclear Information System (INIS)

    This User's Manual is an attempt to provide for teaching and training purposes, a series of well thought out demonstrative experiments in neutron activation analysis based on the utilization of an isotopic neutron source. In some cases, these ideas can be applied to solve practical analytical problems. 19 refs, figs and tabs

  2. Pulsed neutron source and instruments at neutron facility

    Energy Technology Data Exchange (ETDEWEB)

    Teshigawara, Makoto; Aizawa, Kazuya; Suzuki, Jun-ichi; Morii, Yukio; Watanabe, Noboru [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-11-01

    We report the results of design studies on the optimal target shape, target - moderator coupling, optimal layout of moderators, and neutron instruments for a next generation pulsed spallation source in JAERI. The source utilizes a projected high-intensity proton accelerator (linac: 1.5 GeV, {approx}8 MW in total beam power, compressor ring: {approx}5 MW). We discuss the target neutronics, moderators and their layout. The sources is designed to have at least 30 beam lines equipped with more than 40 instruments, which are selected tentatively to the present knowledge. (author)

  3. An accelerator-based epithermal photoneutron source for BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Nigg, D.W.; Mitchell, H.E.; Harker, Y.D.; Yoon, W.Y. [and others

    1995-11-01

    Therapeutically-useful epithermal-neutron beams for BNCT are currently generated by nuclear reactors. Various accelerator-based neutron sources for BNCT have been proposed and some low intensity prototypes of such sources, generally featuring the use of proton beams and beryllium or lithium targets have been constructed. This paper describes an alternate approach to the realization of a clinically useful accelerator-based source of epithermal neutrons for BNCT that reconciles the often conflicting objectives of target cooling, neutron beam intensity, and neutron beam spectral purity via a two stage photoneutron production process.

  4. The Frankfurt neutron source FRANZ

    Science.gov (United States)

    Alzubaidi, Suha; Bartz, Ulrich; Basten, Markus; Bechtold, Alexander; Chau, Long Phi; Claessens, Christine; Dinter, Hannes; Droba, Martin; Fix, Christopher; Hähnel, Hendrik; Heilmann, Manuel; Hinrichs, Ole; Huneck, Simon; Klump, Batu; Lotz, Marcel; Mäder, Dominik; Meusel, Oliver; Noll, Daniel; Nowottnick, Tobias; Obermayer, Marcus; Payir, Onur; Petry, Nils; Podlech, Holger; Ratzinger, Ulrich; Schempp, Alwin; Schmidt, Stefan; Schneider, Philipp; Seibel, Anja; Schwarz, Malte; Schweizer, Waldemar; Volk, Klaus; Wagner, Christopher; Wiesner, Christoph

    2016-05-01

    A 2MeV proton beam will produce a quasi-Maxwellian neutron spectrum of around 30 keV by the 7Li(p, n)7Be reaction. The experiments are mainly focused on the measurement of differential neutron capture cross sections relevant for the astrophysical s-process in nuclear synthesis. Moreover, proton capture cross sections for the astrophysical p-process can be measured directly with the proton beam. For an efficient time of flight measurement of the neutron energies along the 0.7 m long drift from the Li-target to the sample, 1ns short, intense proton pulses are needed at the target. Additionally, to reach 107 n/cm2/s at the sample, a pulse repetition rate of 250 kHz is intended. After completion and successful running in, FRANZ will become a user facility with internal and external users. The 120 kV injector terminal and the 200mA proton source as well as the low-energy beam transport section and the FRANZ cave have been realized successfully. The 1.9 MV RF accelerator consists of a combined 4-Rod-RFQ/IH-DTL-resonator and is in the RF tuning and power testing phase. The 2 MeV transport and rebuncher section is ready for installation. In a first step FRANZ will offer experimental areas for neutron activation experiments and for proton beam experiments, as mentioned above. From the accelerator physics point of view, FRANZ will be an excellent facility for high current beam investigations and for beam wall interaction studies.

  5. Neutron Scattering Simulations at the University of Kentucky Accelerator Laboratory

    Science.gov (United States)

    Nguyen, Thienan; Jackson, Daniel; Hicks, S. F.; Rice, Ben; Vanhoy, J. R.

    2015-10-01

    The Monte-Carlo N-Particle Transport code (MCNP) has many applications ranging from radiography to reactor design. It has particle interaction capabilities, making it useful for simulating neutron collisions on surfaces of varying compositions. The neutron flux within the accelerator complex at the University of Kentucky was simulated using MCNP. With it, the complex's capabilities to contain and thermalize 7 MeV neutrons produced via 2H(d,n)3He source reaction to an acceptable level inside the neutron hall and adjoining rooms were analyzed. This will aid in confirming the safety of researchers who are working in the adjacent control room. Additionally, the neutron transport simulation was used to analyze the impact of the collimator copper shielding on various detectors located around the neutron scattering hall. The purpose of this was to attempt to explain any background neutrons that are observed at these detectors. The simulation shows that the complex performs very well with regards to neutron containment and thermalization. Also, the tracking information for the paths taken by the neutrons show that most of the neutrons' lives are spent inside the neutron hall. Finally, the neutron counts were analyzed at the positions of the neutron monitor detectors located at 90 and 45 degrees relative to the incident beam direction. This project was supported in part by the DOE NEUP Grant NU-12-KY-UK-0201-05 and the Donald A. Cowan Physics Institute at the University of Dallas.

  6. A telescope for monitoring fast neutron sources

    International Nuclear Information System (INIS)

    In the framework of nuclear waste management, highly radiotoxic long-lived fission products and minor actinides are planned to be transmuted in a sub-critical reactor coupled with an intense external neutron source. The latter source would be created by a high-energy proton beam hitting a high atomic number target. Such a new system, termed an accelerator-driven system (ADS), requires on-line and robust reactivity monitoring. The ratio between the beam current delivered by the accelerator and the reactor power level, or core neutron flux, is the basis of one method which could give access to a core reactivity change. In order to test reactivity measurement technique, some experimental programs use 14-MeV neutrons originating from the interaction of a deuteron beam with a tritium target as an external neutron source. In this case, the target tritium consumption over time precludes use of the beam current for reactivity monitoring and the external neutron source intensity must be monitored directly. A range telescope has been developed for this purpose, consisting of the assembly of a hydrogenous neutron converter and three silicon stages where the recoiling protons are detected. In this article, the performances of such a telescope are presented and compared to Monte-Carlo simulations

  7. Livermore Accelerator Source for Radionuclide Science (LASRS)

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Scott [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bleuel, Darren [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Johnson, Micah [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rusnak, Brian [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Soltz, Ron [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tonchev, Anton [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-05-05

    The Livermore Accelerator Source for Radionuclide Science (LASRS) will generate intense photon and neutron beams to address important gaps in the study of radionuclide science that directly impact Stockpile Stewardship, Nuclear Forensics, and Nuclear Material Detection. The co-location of MeV-scale neutral and photon sources with radiochemical analytics provides a unique facility to meet current and future challenges in nuclear security and nuclear science.

  8. Pulsed neutron sources at Dubna

    International Nuclear Information System (INIS)

    In 1960 the first world repetitively pulsed reactor IBR was put into operation. It was the beginning of the story how fission based pulsed neutron sources at Dubna have survived. The engineers involved have experienced many successes and failures in the course of new sources upgrading to finally come to possess the world's brightest neutron source - IBR-2. The details are being reviewed through the paper. The fission based pulsed neutron sources did not reach their final state as yet- the conceptual views of IBR prospects are being discussed with the goal to double the thermal neutron peak flux (up to 2x1016) and to enhance the cold neutron flux by 10 times (with the present one being as high that of the ISIS cold moderator). (author)

  9. Neutronic Design and Measured Performance of the Low Energy Neutron Source (LENS) Target Moderator Reflector Assembly

    CERN Document Server

    Lavelle, C M; Bogdanov, A; Derenchuk, V P; Kaiser, H; Leuschner, M B; Lone, M A; Lozowski, W; Nann, H; Von Przewoski, B; Remmes, N; Rinckel, T; Shin, Y; Snow, W M; Sokol, P E

    2008-01-01

    The Low Energy Neutron Source (LENS) is an accelerator-based pulsed cold neutron facility under construction at the Indiana University Cyclotron Facility (IUCF). The idea behind LENS is to produce pulsed cold neutron beams starting with ~MeV neutrons from (p,n) reactions in Be which are moderated to meV energies and extracted from a small solid angle for use in neutron instruments which can operate efficiently with relatively broad (~1 msec) neutron pulse widths. Although the combination of the features and operating parameters of this source is unique at present, the neutronic design possesses several features similar to those envisioned for future neutron facilities such as long-pulsed spallation sources (LPSS) and very cold neutron (VCN) sources. We describe the underlying ideas and design details of the target/moderator/reflector system (TMR) and compare measurements of its brightness, energy spectrum, and emission time distribution under different moderator configurations with MCNP simulations. Brightnes...

  10. Ion sources for electrostatic accelerators

    International Nuclear Information System (INIS)

    Maybe the most important part of an electrostatic accelerator system, and also often the most tricky part is the ion source. There has been a rapid growth in activity in ion-source research and development during the last two to three decades. Some of these developments have also been of benefit to electrostatic accelerator users. In this report some of the different types of ion sources used in electrostatic accelerators are described. The list is not complete but more an overview of some of the more commonly used sources. The description is divided into two groups; positive ion sources for single stage electrostatic accelerators and negative ion sources for two stages (i.e. tandem) accelerators

  11. Neutron Production Using Alpha-Be Reaction on the Neutron Generator Accelerator

    International Nuclear Information System (INIS)

    In order to obtain data for development of small scale Accelerator Driven System (ADS), calculations of neutron production that use alpha-Be reaction on the acceleration energy range of 100 to 500 keV have been carried out. The result of neutron yield calculation was compared with calculation result of D-T reaction and both calculations were treated for thick target. At the energy of 100 keV; alpha-Be reaction produces neutron yield about 1/10 compared to that of D-T reaction and increases to 1/5 at energy of 500 keV. At the same acceleration voltage of 250 kV, where the alpha energy is 500 keV and deuteron energy is 250 keV; the neutron yield of alpha-Be reaction is 1/3 of that in D-T reaction. On the last mentioned condition and considering that target cost of Be is cheaper than the cost of T, neutron production on a neutron generator accelerator that uses alpha-Be reaction is a competitive method as neutron source, especially for ADS. (author)

  12. Particle Acceleration in Astrophysical Sources

    CERN Document Server

    Amato, Elena

    2015-01-01

    Astrophysical sources are extremely efficient accelerators. Some sources emit photons up to multi-TeV energies, a signature of the presence, within them, of particles with energies much higher than those achievable with the largest accelerators on Earth. Even more compelling evidence comes from the study of Cosmic Rays, charged relativistic particles that reach the Earth with incredibly high energies: at the highest energy end of their spectrum, these subatomic particles are carrying a macroscopic energy, up to a few Joules. Here I will address the best candidate sources and mechanisms as cosmic particle accelerators. I will mainly focus on Galactic sources such as Supernova Remnants and Pulsar Wind Nebulae, which being close and bright, are the best studied among astrophysical accelerators. These sources are held responsible for most of the energy that is put in relativistic particles in the Universe, but they are not thought to accelerate particles up to the highest individual energies, $\\approx 10^{20}$ eV...

  13. Material selection for spallation neutron source windows

    Energy Technology Data Exchange (ETDEWEB)

    Sordo, F. [ETSII/Universidad Politecnica de Madrid, J. Gutierrez Abascal, 2-28006 Madrid (Spain); Abanades, A. [ETSII/Universidad Politecnica de Madrid, J. Gutierrez Abascal, 2-28006 Madrid (Spain)], E-mail: abanades@etsii.upm.es; Lafuente, A.; Martinez-Val, J.M. [ETSII/Universidad Politecnica de Madrid, J. Gutierrez Abascal, 2-28006 Madrid (Spain); Perlado, M. [Instituto de Fusion Nuclear (DENIM)/ETSII/Universidad Politecnica, Madrid, J. Gutierrez Abascal, 2-28006 Madrid (Spain)

    2009-11-15

    High performance neutron sources are being proposed for many scientific and industrial applications, ranging from material studies, hybrid reactors and transmutation of nuclear wastes. In the case of transmutation of nuclear wastes, accelerator driven systems (ADS) are considered as one of the main technical options for such purpose. In ADS a high performance spallation neutron source becomes an essential element for its operation and control. This spallation source must fulfil very challenging nuclear and thermo-mechanical requirements, because of the high neutron rates needed in ADS. The material selection for this key component becomes of paramount importance, particularly the source window that separates the vacuum accelerator tube from the spallation material where the accelerated protons impinge. In this paper, an integral analysis of spallation sources is done, taking as a reference the projects in this field proposal in the framework of European projects. Our analysis and calculations show that titanium and vanadium alloys are more suitable than steel as structural material for an industrial ADS beam window, mostly due to its irradiation damage resistance.

  14. Condensed matter and materials research using neutron diffraction and spectroscopy: reactor and pulsed neutron sources

    International Nuclear Information System (INIS)

    The paper provides a short, and partial view of the neutron scattering technique applied to condensed matter and materials research. Reactor and accelerator-based neutron spectrometers are discussed, together with examples of research projects that illustrate the puissance and modern applications of neutron scattering. Some examples are chosen to show the range of facilities available at the medium flux reactor operated by Casaccia ENEA, Roma and the advanced, pulsed spallation neutron source at the Rutherford Appleton Laboratory, Oxfordshire. (author)

  15. Development of neutron calibration field using accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Baba, Mamoru [Tohoku Univ., Cyclotron and Radioisotope Center, Sendai, Miyagi (Japan)

    2003-03-01

    A brief summary is given on the fast neutron calibration fields for 1) 8 keV to 15 MeV range, and 2) 30-80 MeV range. The field for 8 keV to 15 MeV range was developed at the Fast Neutron Laboratory (FNL) at Tohoku University using a 4.5 MV pulsed Dynamitron accelerator and neutron production reactions, {sup 45}Sc(p, n), {sup 7}Li(p, n), {sup 3}H(p, n), D(d, n) and T(d, n). The latter 30-80 MeV fields are setup at TIARA of Takasaki Establishment of Japan Atomic Energy Research Institute, and at Cyclotron Radio Isotope Center (CYRIC) of Tohoku University using a 90 MeV AVF cyclotron and the {sup 7}Li(p, n) reaction. These fields have been applied for various calibration of neutron spectrometers and dosimeters, and for irradiation purposes. (author)

  16. The tokamak as a neutron source

    International Nuclear Information System (INIS)

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

  17. Deuteron and neutron induced activation in the Eveda accelerator materials: implications for the accelerator maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, M.; Sanz, J.; Garcia, N.; Cabellos, O. [Madrid Univ. Politecnica, C/ Jose Gutierrez Abascal, lnstituto de Fusion Nuclear (Spain); Sauvan, R. [Universidad Nacional de Educacion a Distancia (UNED), Madrid (Spain); Moreno, C.; Sedano, L.A. [CIEMAT-Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, Association Euratom-CIEMAT, Madrid (Spain)

    2007-07-01

    Full text of publication follows: The IFMIF (International Fusion Materials Irradiation Facility) is an accelerator-based DLi neutron source designed to test fusion reactor candidate materials for high fluence neutrons. Before deciding IFMIF construction, an engineering design and associated experimental data acquisition, defined as EVEDA, has been proposed. Along the EVEDA accelerator, deuteron beam losses collide with the accelerator materials, producing activation and consequent radiations responsible of dose. Calculation of the dose rates in the EVEDA accelerator room is necessary in order to analyze the feasibility for manual maintenance. Dose rates due to the activation produced by the deuteron beam losses interaction with the accelerator materials, will be calculated with the ACAB activation code, using EAF2007 library for deuteron activation cross-sections. Also, dose rates from the activation induced by the neutron source produced by the interaction of deuteron beam losses with the accelerator materials and the deuterium implanted in the structural lattice, will be calculated with the SRIM2006, TMAP7, DROSG2000/NEUYIE, MCNPX and ACAB codes. All calculations will be done for the EVEDA accelerator with the room temperature DTL structure, which is based on copper cavities for the DTL. Some calculations will be done for the superconducting DTL structure, based on niobium cavities for the DTL working at cryogenic temperature. Final analysis will show the dominant mechanisms and major radionuclides contributing to the surface dose rates. (authors)

  18. Accelerator Based Neutron Beams for Neutron Capture Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yanch, Jacquelyn C.

    2003-04-11

    The DOE-funded accelerator BNCT program at the Massachusetts Institute of Technology has resulted in the only operating accelerator-based epithermal neutron beam facility capable of generating significant dose rates in the world. With five separate beamlines and two different epithermal neutron beam assemblies installed, we are currently capable of treating patients with rheumatoid arthritis in less than 15 minutes (knee joints) or 4 minutes (finger joints) or irradiating patients with shallow brain tumors to a healthy tissue dose of 12.6 Gy in 3.6 hours. The accelerator, designed by Newton scientific Incorporated, is located in dedicated laboratory space that MIT renovated specifically for this project. The Laboratory for Accelerator Beam Applications consists of an accelerator room, a control room, a shielded radiation vault, and additional laboratory space nearby. In addition to the design, construction and characterization of the tandem electrostatic accelerator, this program also resulted in other significant accomplishments. Assemblies for generating epithermal neutron beams were designed, constructed and experimentally evaluated using mixed-field dosimetry techniques. Strategies for target construction and target cooling were implemented and tested. We demonstrated that the method of submerged jet impingement using water as the coolant is capable of handling power densities of up to 6 x 10(sup 7) W/m(sup 2) with heat transfer coefficients of 10(sup 6)W/m(sup 2)-K. Experiments with the liquid metal gallium demonstrated its superiority compared with water with little effect on the neutronic properties of the epithermal beam. Monoenergetic proton beams generated using the accelerator were used to evaluate proton RBE as a function of LET and demonstrated a maximum RBE at approximately 30-40 keV/um, a finding consistent with results published by other researchers. We also developed an experimental approach to biological intercomparison of epithermal beams and

  19. Materials for spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-03-01

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

  20. Monitoring of D-T accelerator neutron output in a PGNAA system using silicon carbide detectors

    International Nuclear Information System (INIS)

    Silicon carbide (SiC) detectors are being employed to monitor the neutron output of the D-T accelerator in a pulsed Prompt Gamma Neutron Activation Analysis (PGNAA) system. Detection of the source neutrons relies on energetic neutron reactions in the detector material. Experimental testing has been performed to confirm that the detector response is caused by fast neutrons from the accelerator source. Modeling calculations have also been carried out to provide additional verification. Use of the SiC detectors in the PGNAA system is expected to assist in evaluating system performance as well as ensuring accurate data interpretation and analysis

  1. Monitoring of D-T accelerator neutron output in a PGNAA system using silicon carbide detectors

    Science.gov (United States)

    Dulloo, Abdul R.; Ruddy, Frank H.; Seidel, John G.; Petrović, Bojan

    2001-07-01

    Silicon carbide (SiC) detectors are being employed to monitor the neutron output of the D-T accelerator in a pulsed Prompt Gamma Neutron Activation Analysis (PGNAA) system. Detection of the source neutrons relies on energetic neutron reactions in the detector material. Experimental testing has been performed to confirm that the detector response is caused by fast neutrons from the accelerator source. Modeling calculations have also been carried out to provide additional verification. Use of the SiC detectors in the PGNAA system is expected to assist in evaluating system performance as well as ensuring accurate data interpretation and analysis.

  2. Miniature neutron sources: Thermal neutron sources and their uses in the academic field

    International Nuclear Information System (INIS)

    The three levels of thermal neutron sources are introduced: university laboratory sources; infrastructure sources; and world-class sources; and the needs for each kind and their inter-dependence will be emphasized. A description of the possibilities for university sources based on α-Be reactions or spontaneous fission emission is given, and current experience with them is described. A new generation of infrastructure sources is needed to continue the regional programs based on small reactors. Some possibilities for accelerator sources that could meet this need are considered

  3. Fusion Based Neutron Sources for Security Applications: Neutron Techniques

    OpenAIRE

    Albright, S.; Seviour, Rebecca

    2014-01-01

    The current reliance on X-Rays and intelligence for na- tional security is insufficient to combat the current risks of smuggling and terrorism seen on an international level. There are a range of neutron based security techniques which have the potential to dramatically improve national security. Neutron techniques can be broadly grouped into neutron in/neutron out and neutron in/photon out tech- niques. The use of accelerator based fusion devices will potentially enable to wide spread applic...

  4. A bright neutron source driven by relativistic transparency of solids

    Science.gov (United States)

    Roth, M.; Jung, D.; Falk, K.; Guler, N.; Deppert, O.; Devlin, M.; Favalli, A.; Fernandez, J.; Gautier, D. C.; Geissel, M.; Haight, R.; Hamilton, C. E.; Hegelich, B. M.; Johnson, R. P.; Kleinschmidt, A.; Merrill, F.; Schaumann, G.; Schoenberg, K.; Schollmeier, M.; Shimada, T.; Taddeucci, T.; Tybo, J. L.; Wagner, F.; Wender, S. A.; Wilde, C. H.; Wurden, G. A.

    2016-03-01

    Neutrons are a unique tool to alter and diagnose material properties and excite nuclear reactions with a large field of applications. It has been stated over the last years, that there is a growing need for intense, pulsed neutron sources, either fast or moderated neutrons for the scientific community. Accelerator based spallation sources provide unprecedented neutron fluxes, but could be complemented by novel sources with higher peak brightness that are more compact. Lasers offer the prospect of generating a very compact neutron source of high peak brightness that could be linked to other facilities more easily. We present experimental results on the first short pulse laser driven neutron source powerful enough for applications in radiography. For the first time an acceleration mechanism (BOA) based on the concept of relativistic transparency has been used to generate neutrons. This mechanism not only provides much higher particle energies, but also accelerated the entire target volume, thereby circumventing the need for complicated target treatment and no longer limited to protons as an intense ion source. As a consequence we have demonstrated a new record in laser-neutron production, not only in numbers, but also in energy and directionality based on an intense deuteron beam. The beam contained, for the first time, neutrons with energies in excess of 100 MeV and showed pronounced directionality, which makes then extremely useful for a variety of applications. The results also address a larger community as it paves the way to use short pulse lasers as a neutron source. They can open up neutron research to a broad academic community including material science, biology, medicine and high energy density physics as laser systems become more easily available to universities and therefore can complement large scale facilities like reactors or particle accelerators. We believe that this has the potential to increase the user community for neutron research largely.

  5. Neutron Transport Methods for Accelerator-Driven Systems

    Energy Technology Data Exchange (ETDEWEB)

    Nicholas Tsoulfanidis; Elmer Lewis

    2005-02-09

    The objective of this project has been to develop computational methods that will enable more effective analysis of Accelerator Driven Systems (ADS). The work is centered at the University of Missouri at Rolla, with a subcontract at Northwestern University, and close cooperation with the Nuclear Engineering Division at Argonne National Laboratory. The work has fallen into three categories. First, the treatment of the source for neutrons originating from the spallation target which drives the neutronics calculations of the ADS. Second, the generalization of the nodal variational method to treat the R-Z geometry configurations frequently needed for scoping calculations in Accelerator Driven Systems. Third, the treatment of void regions within variational nodal methods as needed to treat the accelerator beam tube.

  6. Fast neutron capture with a white neutron source

    International Nuclear Information System (INIS)

    A system has been developed at the Los Alamos National Laboratory to measure gamma-rays following fast neutron reactions. The neutron beam is produced by bombarding a thick tantalum target with the 800 MeV proton beam from the LAMPF accelerator. Incident neutron energies, from 1 to over 200 MeV, are determined by their times of flight over a 7.6-m flight path. The gamma-rays are detected in five 7.6 x 7.6-cm cylindrical bismuth germanate (BGO) detectors which span an angular range from 450 to 1450 in the reaction plane. With this system it is possible to simultaneously measure the cross section and angular distribution of gamma-rays as a function of neutron energy. The results for the cross section of the 12C(n,n'γ=4.44 MeV) reaction at 900 and 1250 show good agreement with previous measurements while the complete angular distributions show the need for a large a4 coefficient which was not previously observed. Preliminary results for the 12C(n,n'γ=15.1 MeV) reaction have also been obtained. The data obtained for the 40Ca(n,γ0) reaction in the region of the giant dipole resonance demonstrate the unique capabilities of this system. Future developments to the neutron source which will enhance the capabilities of the system are presented. 14 references

  7. Fast neutron leakage in 18 MeV medical electron accelerator

    CERN Document Server

    Paredes, L; Balcazar, M; Tavera, L; Camacho, E

    1999-01-01

    In this work the neutron fluence of the Varian Clinac 2100C Medical Accelerator has been evaluated using CR39 track dosimeter. The assessment of fast neutron dose to a patient for typical treatment of 200 cGy with an 18 MV photons beam is performed at surface-source distance of 100 cm with a field size of 20x20 cm sup 2. Fast neutron leakage around of the accelerator head is evaluated.

  8. Compact ion accelerator source

    Energy Technology Data Exchange (ETDEWEB)

    Schenkel, Thomas; Persaud, Arun; Kapadia, Rehan; Javey, Ali

    2014-04-29

    An ion source includes a conductive substrate, the substrate including a plurality of conductive nanostructures with free-standing tips formed on the substrate. A conductive catalytic coating is formed on the nanostructures and substrate for dissociation of a molecular species into an atomic species, the molecular species being brought in contact with the catalytic coating. A target electrode placed apart from the substrate, the target electrode being biased relative to the substrate with a first bias voltage to ionize the atomic species in proximity to the free-standing tips and attract the ionized atomic species from the substrate in the direction of the target electrode.

  9. Optimal Neutron Source and Beam Shaping Assembly for Boron Neutron Capture Therapy

    CERN Document Server

    Vujic, J L; Greenspan, E; Guess, S; Karni, Y; Kastenber, W E; Kim, L; Leung, K N; Regev, D; Verbeke, J M; Waldron, W L; Zhu, Y

    2003-01-01

    There were three objectives to this project: (1) The development of the 2-D Swan code for the optimization of the nuclear design of facilities for medical applications of radiation, radiation shields, blankets of accelerator-driven systems, fusion facilities, etc. (2) Identification of the maximum beam quality that can be obtained for Boron Neutron Capture Therapy (BNCT) from different reactor-, and accelerator-based neutron sources. The optimal beam-shaping assembly (BSA) design for each neutron source was also to e obtained. (3) Feasibility assessment of a new neutron source for NCT and other medical and industrial applications. This source consists of a state-of-the-art proton or deuteron accelerator driving and inherently safe, proliferation resistant, small subcritical fission assembly.

  10. Optimal Neutron Source and Beam Shaping Assembly for Boron Neutron Capture Therapy

    International Nuclear Information System (INIS)

    There were three objectives to this project: (1) The development of the 2-D Swan code for the optimization of the nuclear design of facilities for medical applications of radiation, radiation shields, blankets of accelerator-driven systems, fusion facilities, etc. (2) Identification of the maximum beam quality that can be obtained for Boron Neutron Capture Therapy (BNCT) from different reactor-, and accelerator-based neutron sources. The optimal beam-shaping assembly (BSA) design for each neutron source was also to e obtained. (3) Feasibility assessment of a new neutron source for NCT and other medical and industrial applications. This source consists of a state-of-the-art proton or deuteron accelerator driving and inherently safe, proliferation resistant, small subcritical fission assembly

  11. Optimal Neutron Source & Beam Shaping Assembly for Boron Neutron Capture Therapy

    Energy Technology Data Exchange (ETDEWEB)

    J. Vujic; E. Greenspan; W.E. Kastenber; Y. Karni; D. Regev; J.M. Verbeke, K.N. Leung; D. Chivers; S. Guess; L. Kim; W. Waldron; Y. Zhu

    2003-04-30

    There were three objectives to this project: (1) The development of the 2-D Swan code for the optimization of the nuclear design of facilities for medical applications of radiation, radiation shields, blankets of accelerator-driven systems, fusion facilities, etc. (2) Identification of the maximum beam quality that can be obtained for Boron Neutron Capture Therapy (BNCT) from different reactor-, and accelerator-based neutron sources. The optimal beam-shaping assembly (BSA) design for each neutron source was also to e obtained. (3) Feasibility assessment of a new neutron source for NCT and other medical and industrial applications. This source consists of a state-of-the-art proton or deuteron accelerator driving and inherently safe, proliferation resistant, small subcritical fission assembly.

  12. Neutronic parameters characterizing accelerator driven system (ADS)

    International Nuclear Information System (INIS)

    An hybrid system is a reactor where an external source of spallation neutrons is supplied to a subcritical multiplying medium. The neutronic parameters characterising such a system include, in addition to the multiplication factor which measures the sub-criticality level, another physics parameter measuring the 'importance' of the external source. The aim of this thesis is, on the one hand, to investigate basic neutronic phenomena taking place in fast sub- critical media in either steady-state or transient operation, and, on the other hand, to assess the performance of the ERANOS neutronic code package applied to the analysis of such systems. To this aim, the first part of the work is focused on the MUSE program and in particular the MUSE3 experiment, which consists of different sub-critical configurations driven by a 14-MeV neutron source. This study has been pursued in two directions : the first one was the interpretation of the calculation-experiment (C-E) discrepancies which lead to the development of original calculation methods for sensitivity studies ; the second one was the experimental analysis which allowed an extensive neutronic characterization of the sub-critical system. A correlation between the external source importance and some directly measurable parameters (i.e. fission rate) was derived. The second part of the thesis addresses representativity issues between an experimental facility and an actual power reactor. Important conclusions have been drawn with regard to the operation of an ADS. Finally, representativity studies lead to the recommendation that a demonstration reactor should be built before an industrial plant is constructed. (author)

  13. Optical polarizing neutron devices designed for pulsed neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, M.; Kurahashi, K.; Endoh, Y. [Tohoku Univ, Sendai (Japan); Itoh, S. [National Lab. for High Energy Physics, Tsukuba (Japan)

    1997-09-01

    We have designed two polarizing neutron devices for pulsed cold neutrons. The devices have been tested at the pulsed neutron source at the Booster Synchrotron Utilization Facility of the National Laboratory for High Energy Physics. These two devices proved to have a practical use for experiments to investigate condensed matter physics using pulsed cold polarized neutrons.

  14. Neutron-emission measurements at a white neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Haight, Robert C [Los Alamos National Laboratory

    2010-01-01

    Data on the spectrum of neutrons emittcd from neutron-induced reactions are important in basic nuclear physics and in applications. Our program studies neutron emission from inelastic scattering as well as fission neutron spectra. A ''white'' neutron source (continuous in energy) allows measurements over a wide range of neutron energies all in one experiment. We use the tast neutron source at the Los Alamos Neutron Science Center for incident neutron energies from 0.5 MeV to 200 MeV These experiments are based on double time-of-flight techniques to determine the energies of the incident and emitted neutrons. For the fission neutron measurements, parallel-plate ionization or avalanche detectors identify fission in actinide samples and give the required fast timing pulse. For inelastic scattering, gamma-ray detectors provide the timing and energy spectroscopy. A large neutron-detector array detects the emitted neutrons. Time-of-flight techniques are used to measure the energies of both the incident and emitted neutrons. Design considerations for the array include neutron-gamma discrimination, neutron energy resolution, angular coverage, segmentation, detector efficiency calibration and data acquisition. We have made preliminary measurements of the fission neutron spectra from {sup 235}U, {sup 238}U, {sup 237}Np and {sup 239}Pu. Neutron emission spectra from inelastic scattering on iron and nickel have also been investigated. The results obtained will be compared with evaluated data.

  15. Sweden to host a new neutron source

    CERN Multimedia

    Anaïs Schaeffer

    2012-01-01

    The first European neutron source, currently under development, should commence operations by the end of this decade. Its aim: to produce beams of neutrons that can penetrate into the heart of matter without damaging it and reveal its secrets.   An artist's impression of what the ESS should look like in 2019. At the southern end of Sweden, a town called Lund is preparing for the arrival of the world's most powerful neutron source: the European Spallation Source (ESS). Construction is scheduled to start at the beginning of next year, and the facility is expected to become operational by 2019, when it will produce its first neutron beams. “The ESS is the result of an idea that began 20 years ago!” underlines Mats Lindroos, in charge of the ESS Accelerator Division. “Today, 17 European countries support the project, including Sweden, Denmark and Norway, who together account for 50% of the construction funding.” The ESS, whose design is al...

  16. Design of a neutron source for calibration

    International Nuclear Information System (INIS)

    The neutron spectra produced by an isotopic neutron source located at the center of moderating media were calculated using Monte Carlo method in the aim to design a neutron source for calibration purposes. To improve the evaluation of the dosimetric quantities, is recommended to calibrate the radiation protection devices with calibrated neutron sources whose neutron spectra being similar to those met in practice. Here, a 239Pu-Be neutron source was inserted in H2O, D2O and polyethylene cylindrical moderators in order to produce neutron spectra that resembles spectra found in workplaces

  17. Treatment Planning for Accelerator-Based Boron Neutron Capture Therapy

    Science.gov (United States)

    Herrera, María S.; González, Sara J.; Minsky, Daniel M.; Kreiner, Andrés J.

    2010-08-01

    Glioblastoma multiforme and metastatic melanoma are frequent brain tumors in adults and presently still incurable diseases. Boron Neutron Capture Therapy (BNCT) is a promising alternative for this kind of pathologies. Accelerators have been proposed for BNCT as a way to circumvent the problem of siting reactors in hospitals and for their relative simplicity and lower cost among other advantages. Considerable effort is going into the development of accelerator-based BNCT neutron sources in Argentina. Epithermal neutron beams will be produced through appropriate proton-induced nuclear reactions and optimized beam shaping assemblies. Using these sources, computational dose distributions were evaluated in a real patient with diagnosed glioblastoma treated with BNCT. The simulated irradiation was delivered in order to optimize dose to the tumors within the normal tissue constraints. Using Monte Carlo radiation transport calculations, dose distributions were generated for brain, skin and tumor. Also, the dosimetry was studied by computing cumulative dose-volume histograms for volumes of interest. The results suggest acceptable skin average dose and a significant dose delivered to tumor with low average whole brain dose for irradiation times less than 60 minutes, indicating a good performance of an accelerator-based BNCT treatment.

  18. Cosmic ray acceleration by binary neutron stars

    Science.gov (United States)

    Kundt, W.

    Young binary neutron stars, the elder brothers of pulsars, are proposed as the boosters of the ionic component of cosmic rays. Their rotational energy can be converted into beams of cosmic rays if there is enough coupling between the corotating magnetosphere and the impinging plasma, in a manner similar to the sparking of a grindstone. Power-law spectra in energy are obtained from a power-law dependence of the accelerating fields. The upper cutoff energy should not greatly exceed 10 to the 20th eV. The observed ionic cosmic-ray spectrum would result from a superposition of the injection by no more than about one million young binary neutron stars.

  19. Neutron sources for the medical use

    International Nuclear Information System (INIS)

    Recently encouraging results of the neutron radiation therapy have been obtained in clinical trials. In addition to the therapy, the neutrons are applied to the diagnosis besides the production of radioisotopes, that is, in-vivo activation analysis and neutron radiograph. In the medicine, high energy neutrons are effectively used. The necessary conditions, especially neutron source reactions, angular distributions, etc., and the neutron dosimetry including neutron kerma factors are discussed. Finally the requirements for neutron sources, their related problems and nuclear data are enumerated. (author)

  20. The Spallation Neutron Source Beam Commissioning and Initial Operations

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, Stuart [Argonne National Lab. (ANL), Argonne, IL (United States); Aleksandrov, Alexander V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Allen, Christopher K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Assadi, Saeed [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bartoski, Dirk [University of Texas, Houston, TX (United States). Anderson Cancer Center; Blokland, Willem [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Casagrande, F. [Michigan State Univ., East Lansing, MI (United States); Campisi, I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chu, C. [Michigan State Univ., East Lansing, MI (United States); Cousineau, Sarah M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Crofford, Mark T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Danilov, Viatcheslav [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Deibele, Craig E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dodson, George W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Feshenko, A. [Inst. for Nuclear Research (INR), Moscow (Russian Federation); Galambos, John D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Han, Baoxi [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hardek, T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holmes, Jeffrey A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holtkamp, N. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Howell, Matthew P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jeon, D. [Inst. for Basic Science, Daejeon (Korea); Kang, Yoon W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kasemir, Kay [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kim, Sang-Ho [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kravchuk, L. [Institute for Nuclear Research (INR), Moscow (Russian Federation); Long, Cary D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McManamy, T. [McManamy Consulting, Inc., Middlesex, MA (United States); Pelaia, II, Tom [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Piller, Chip [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Plum, Michael A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pogge, James R. [Tennessee Technological Univ., Cookeville, TN (United States); Purcell, John David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shea, T. [European Spallation Source, Lund (Sweden); Shishlo, Andrei P [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sibley, C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stockli, Martin P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stout, D. [Michigan State Univ., East Lansing, MI (United States); Tanke, E. [European Spallation Source, Lund (Sweden); Welton, Robert F [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zhang, Y. [Michigan State Univ., East Lansing, MI (United States); Zhukov, Alexander P [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-01

    The Spallation Neutron Source (SNS) accelerator delivers a one mega-Watt beam to a mercury target to produce neutrons used for neutron scattering materials research. It delivers ~ 1 GeV protons in short (< 1 us) pulses at 60 Hz. At an average power of ~ one mega-Watt, it is the highest-powered pulsed proton accelerator. The accelerator includes the first use of superconducting RF acceleration for a pulsed protons at this energy. The storage ring used to create the short time structure has record peak particle per pulse intensity. Beam commissioning took place in a staged manner during the construction phase of SNS. After the construction, neutron production operations began within a few months, and one mega-Watt operation was achieved within three years. The methods used to commission the beam and the experiences during initial operation are discussed.

  1. Characterization of the DD-neutron source for the 80 degrees beam line of the fusion neutronics source (FNS)

    International Nuclear Information System (INIS)

    The specification of the d-D neutron source with a titanium deuteride target of the FNS facility was investigated in order to utilize the d-D neutron source for fusion neutronics researches. The characteristics of neutron produced by the d-D reaction were described based on the reaction kinematics, and the target assembly of the accelerator was modeled for the MCNP calculation in detail. In order to validate this calculation, the angular distribution of the neutron was measured with the activation foil method. The measured reaction rates were well predicted by the MCNP calculation, and the validity of the present calculation was confirmed. A MCNP source term for analyses calculations of experiments with DD neutrons was prepared from the results of the above calculation. (author)

  2. Passive neutron dosemeter-spectrometer for high-energy accelerators

    International Nuclear Information System (INIS)

    A passive neutron dosemeter-spectrometer (PNDS) with fission fragments converters is described. The results obtained show that it is a convenient and reliable instrument for neutron dose equivalent measurement in the calibration performing and response investigations of personnel dosemeters in mixed radiation fields behind accelerator shielding. Because of the possibility of neutron spectrum estimation in a wide energy range PNDS using is promissing in the neutron radiation fields research and also as an accidental neutron dosemeter. 23 refs.; 10 figs.; 4 tabs

  3. Accelerator driven reactors, - the significance of the energy distribution of spallation neutrons on the neutron statistics

    International Nuclear Information System (INIS)

    In order to make correct predictions of the second moment of statistical nuclear variables, such as the number of fissions and the number of thermalized neutrons, the dependence of the energy distribution of the source particles on their number should be considered. It has been pointed out recently that neglecting this number dependence in accelerator driven systems might result in bad estimates of the second moment, and this paper contains qualitative and quantitative estimates of the size of these efforts. We walk towards the requested results in two steps. First, models of the number dependent energy distributions of the neutrons that are ejected in the spallation reactions are constructed, both by simple assumptions and by extracting energy distributions of spallation neutrons from a high-energy particle transport code. Then, the second moment of nuclear variables in a sub-critical reactor, into which spallation neutrons are injected, is calculated. The results from second moment calculations using number dependent energy distributions for the source neutrons are compared to those where only the average energy distribution is used. Two physical models are employed to simulate the neutron transport in the reactor. One is analytical, treating only slowing down of neutrons by elastic scattering in the core material. For this model, equations are written down and solved for the second moment of thermalized neutrons that include the distribution of energy of the spallation neutrons. The other model utilizes Monte Carlo methods for tracking the source neutrons as they travel inside the reactor material. Fast and thermal fission reactions are considered, as well as neutron capture and elastic scattering, and the second moment of the number of fissions, the number of neutrons that leaked out of the system, etc. are calculated. Both models use a cylindrical core with a homogenous mixture of core material. Our results indicate that the number dependence of the energy

  4. How to Produce a Reactor Neutron Spectrum Using a Proton Accelerator

    Science.gov (United States)

    Burns, K.; Wootan, D.; Gates, R.; Schmitt, B.; Asner, D. M.

    A method for reproducing the neutron energy spectrum present in the core of an operating nuclear reactor using an engineered target in an accelerator proton beam is proposed. The protons interact with a target to create neutrons through various (p,n) type reactions. Spectral tailoring of the emitted neutrons can be used to modify the energy of the generated neutron spectrum to represent various reactor spectra. Through the use of moderators and reflectors, the neutron spectrum can be modified to reproduce many different spectra of interest including spectra in small thermal test reactors, large pressurized water reactors, and fast reactors. The particular application of this methodology is the design of an experimental approach for using an accelerator to measure the betas produced during fission to be used to reduce uncertainties in the interpretation of reactor antineutrino measurements. This approach involves using a proton accelerator to produce a neutron field representative of a power reactor, and using this neutron field to irradiate fission foils of the primary isotopes contributing to fission in the reactor, creating unstable, neutron rich fission products that subsequently beta decay and emit electron antineutrinos. A major advantage of an accelerator neutron source over a neutron beam from a thermal reactor is that the fast neutrons can be slowed down or tailored to approximate various power reactor spectra. An accelerator based neutron source that can be tailored to match various reactor neutron spectra provides an advantage for control in studying how changes in the neutron spectra affect parameters such as the resulting fission product beta spectrum.

  5. How to produce a reactor neutron spectrum using a proton accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Burns, Kimberly A.; Wootan, David W.; Gates, Robert O.; Schmitt, Bruce E.; Asner, David M.

    2015-01-01

    A method for reproducing the neutron energy spectrum present in the core of an operating nuclear reactor using an engineered target in an accelerator proton beam is proposed. The protons interact with a target to create neutrons through various (p,n) type reactions. Spectral tailoring of the emitted neutrons can be used to modify the energy of the generated neutron spectrum to represent various reactor spectra. Through the use of moderators and reflectors, the neutron spectrum can be modified to reproduce many different spectra of interest including spectra in small thermal test reactors, large pressurized water reactors, and fast reactors. The particular application of this methodology is the design of an experimental approach for using an accelerator to measure the betas produced during fission to be used to reduce uncertainties in the interpretation of reactor antineutrino measurements. This approach involves using a proton accelerator to produce a neutron field representative of a power reactor, and using this neutron field to irradiate fission foils of the primary isotopes contributing to fission in the reactor, creating unstable, neutron rich fission products that subsequently beta decay and emit electron antineutrinos. A major advantage of an accelerator neutron source over a neutron beam from a thermal reactor is that the fast neutrons can be slowed down or tailored to approximate various power reactor spectra. An accelerator based neutron source that can be tailored to match various reactor neutron spectra provides an advantage for control in studying how changes in the neutron spectra affect parameters such as the resulting fission product beta spectrum.

  6. Accelerator tube construction and characterization for a tandem-electrostatic-quadrupole for accelerator-based boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Cartelli, D.; Thatar Vento, V. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)] [CONICET, Av Rivadavia 1917 (1033), Buenos Aires (Argentina); Castell, W. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina); Di Paolo, H. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)] [Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin (Argentina); Kesque, J.M. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina); Bergueiro, J. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)] [CONICET, Av Rivadavia 1917 (1033), Buenos Aires (Argentina); Valda, A.A. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)] [Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin (Argentina)

    2011-12-15

    The accelerator tubes are essential components of the accelerator. Their function is to transport and accelerate a very intense proton or deuteron beam through the machine, from the ion source to the neutron production target, without significant losses. In this contribution, we discuss materials selected for the tube construction, the procedures used for their assembly and the testing performed to meet the stringent requirements to which it is subjected.

  7. Characterization of short-pulse laser driven neutron source

    Science.gov (United States)

    Falk, Katerina; Jung, Daniel; Guler, Nevzat; Deppert, Oliver; Devlin, Matthew; Fernandez, J. C.; Gautier, D. C.; Geissel, M.; Haight, R. C.; Hegelich, B. M.; Henzlova, Daniela; Ianakiev, K. D.; Iliev, Metodi; Johnson, R. P.; Merrill, F. E.; Schaumann, G.; Schoenberg, K.; Shimada, T.; Taddeucci, T. N.; Tybo, J. L.; Wagner, F.; Wender, S. A.; Wurden, G. A.; Favalli, Andrea; Roth, Markus

    2014-10-01

    We present a full spectral characterization of a novel laser driven neutron source, which employed the Break Out Afterburner ion acceleration mechanism. Neutrons were produced by nuclear reactions of the ions deposited on Be or Cu converters. We observed neutrons at energies up to 150 MeV. The neutron spectra were measured by five neutron time-of-flight detectors at various positions and distances from the source. The nTOF detectors observed that emission of neutrons is a superposition of an isotropic component peaking at 3.5--5 MeV resulting from nuclear reactions in the converter and a directional component at 25--70 MeV, which was a product of break-up reaction of the forward moving deuterons. Energy shifts due to geometrical effects in BOA were also observed.

  8. Different spectra with the same neutron source

    International Nuclear Information System (INIS)

    Using as source term the spectrum of a 239Pu-Be source several neutron spectra have been calculated using Monte Carlo methods. The source term was located in the centre of spherical moderators made of light water, heavy water and polyethylene of different diameters. Also a 239Pu-Be source was used to measure its neutron spectrum, bare and moderated by water. The neutron spectra were measured at 100 cm with a Bonner spheres spectrometer. Monte Carlo calculations were used to calculate the neutron spectra of bare and water-moderated spectra that were compared with those measured with the spectrometer. Resulting spectra are similar to those found in power plants with PWR, BWR and Candu nuclear reactors. Beside the spectra the dosimetric features were determined. Using moderators and a single neutron source can be produced neutron spectra alike those found in workplaces, this neutron fields can be utilized to calibrate neutron dosimeters and area monitors. (Author)

  9. Design and demonstration of a quasi-monoenergetic neutron source

    CERN Document Server

    Joshi, T H; Mozin, V; Norman, E B; Sorensen, P; Foxe, M; Bench, G; Bernstein, A

    2014-01-01

    The design of a neutron source capable of producing 24 and 70 keV neutron beams with narrow energy spread is presented. The source exploits near-threshold kinematics of the $^{7}$Li(p,n)$^{7}$Be reaction while taking advantage of the interference `notches' found in the scattering cross-sections of iron. The design was implemented and characterized at the Center for Accelerator Mass Spectrometry at Lawrence Livermore National Laboratory. Alternative filters such as vanadium and manganese are also explored and the possibility of studying the response of different materials to low-energy nuclear recoils using the resultant neutron beams is discussed.

  10. Design Optimization and the path towards a 2 MW Spallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    M. Blaskiewicz; N. Catalan-Lasheras; D. Davino; A. Fedotov; Y. Lee; N. Malitsky; Y. Papaphilippou; D. Raparia; A. Shishlo; N. Tsoupas; J. Wei; W. Weng; S. Zhang; J. Billen; S. Kurennoy; S. Nath; J. Stovall; H. Takeda; L. Young; R. Keller; J. Staples; A. Aleksandrov; Y. Cho; P. Chu; S. Cousineau; V. Danilov; M. Doleans; J. Galambos; J. Holmes; N. Holtkamp; D. Jeon; S. Kim; R. Kustom; E. Tanke; W. Wan; R. Sundelin

    2001-08-01

    The Spallation Neutron Source (SNS) is designed to ultimately reach an average proton beam power of 2 MW for pulsed neutron production. The SNS physics groups analyze the machine performance within the hardware constraints, optimize the accelerator design, and establish the best path towards a 2 MW and higher spallation neutron source.

  11. Advanced Neutron Source (ANS) Project

    International Nuclear Information System (INIS)

    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

  12. Inertial electro-magnetostatic plasma neutron sources

    International Nuclear Information System (INIS)

    Two types of systems are being studied experimentally as D-T plasma neutron sources. In both concepts, spherical convergence of either electrons or ions or both is used to produce a dense central focus within which D-T fusion reactions produce 14 MeV neutrons. One concept uses nonneutral plasma confinement principles in a Penning type trap. In this approach, combined electrostatic and magnetic fields provide a vacuum potential well within which electrons are confined and focused. A small (6 mm radius) spherical machine has demonstrated a focus of 30 microm radius, with a central density of up to 35 times the Brillouin density limit of a static trap. The resulting electron plasma of up to several 1013 cm-3 provides a multi-kV electrostatic well for confining thermonuclear ions as a neutron source. The second concept (Inertial Electrostatic Confinement, or IEC) uses a high-transparence grid to form a global well for acceleration and confinement of ions. Such a system has demonstrated steady neutron output of 2 x 1010 s-1. The present experiment will scale this to >1011 s-1. Advanced designs based on each concept have been developed recently. In these proposed approaches, a uniform-density electron sphere forms an electrostatic well for ions. Ions so trapped may be focused by spherical convergence to produce a dense core. An alternative approach produces large amplitude spherical oscillations of a confined ion cloud by a small, resonant modulation of the background electrons. In both the advanced Penning trap approach and the advanced IEC approach, the electrons are magnetically insulated from a large (up to 100 kV) applied electrostatic field. The physics of these devices is discussed, experimental design details are given, present observations are analyzed theoretically, and the performance of future advanced systems are predicted

  13. Physics and technology of spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, G.S.

    1998-08-01

    Next to fission and fusion, spallation is an efficient process for releasing neutrons from nuclei. Unlike the other two reactions, it is an endothermal process and can, therefore, not be used per se in energy generation. In order to sustain a spallation reaction, an energetic beam of particles, most commonly protons, must be supplied onto a heavy target. Spallation can, however, play an important role as a source of neutrons whose flux can be easily controlled via the driving beam. Up to a few GeV of energy, the neutron production is roughly proportional to the beam power. Although sophisticated Monte Carlo codes exist to compute all aspects of a spallation facility, many features can be understood on the basis of simple physics arguments. Technically a spallation facility is very demanding, not only because a reliable and economic accelerator of high power is needed to drive the reaction, but also, and in particular, because high levels of radiation and heat are generated in the target which are difficult to cope with. Radiation effects in a spallation environment are different from those commonly encountered in a reactor and are probably even more temperature dependent than the latter because of the high gas production rate. A commonly favored solution is the use of molten heavy metal targets. While radiation damage is not a problem in this case, except for the container, a number of other issues are discussed. (author)

  14. Physics and technology of spallation neutron sources

    International Nuclear Information System (INIS)

    Next to fission and fusion, spallation is an efficient process for releasing neutrons from nuclei. Unlike the other two reactions, it is an endothermal process and can, therefore, not be used per se in energy generation. In order to sustain a spallation reaction, an energetic beam of particles, most commonly protons, must be supplied onto a heavy target. Spallation can, however, play an important role as a source of neutrons whose flux can be easily controlled via the driving beam. Up to a few GeV of energy, the neutron production is roughly proportional to the beam power. Although sophisticated Monte Carlo codes exist to compute all aspects of a spallation facility, many features can be understood on the basis of simple physics arguments. Technically a spallation facility is very demanding, not only because a reliable and economic accelerator of high power is needed to drive the reaction, but also, and in particular, because high levels of radiation and heat are generated in the target which are difficult to cope with. Radiation effects in a spallation environment are different from those commonly encountered in a reactor and are probably even more temperature dependent than the latter because of the high gas production rate. A commonly favored solution is the use of molten heavy metal targets. While radiation damage is not a problem in this case, except for the container, a number of other issues are discussed. (author)

  15. Assessment of neutron dose in Indus Accelerator Complex using CR-39 SSNTD

    International Nuclear Information System (INIS)

    Indus Accelerator Complex (lAC) consists of two synchrotron radiation sources, Indus-1 and Indus-2. Indus-1 is a 450 MeV electron storage ring and Indus-2 is of 2.5 GeV. The radiation environment in lAC is mainly due to Bremsstrahlung and photo-neutrons. Major problems faced in neutron detection in lAC are the severely pulsed nature and gamma interference. The response of flux meters and Rem meters are not adequate for severely pulsed neutron field in IAC. Hence, on line neutron measurement is a challenging problem in the radiation environment of lAC. In order to assess the neutron dose rates in the accelerator complex during various operating conditions, passive integrating type neutron detectors based on CR-39 SSNTD technique were used. The paper describes the details of the measurements carried out and the results

  16. Slow neutron leakage spectra from spallation neutron sources

    International Nuclear Information System (INIS)

    An efficient technique is described for Monte Carlo simulation of neutron beam spectra from target-moderator-reflector assemblies typical of pulsed spallation neutron sources. The technique involves the scoring of the transport-theoretical probability that a neutron will emerge from the moderator surface in the direction of interest, at each collision. An angle-biasing probability is also introduced which further enhances efficiency in simple problems. These modifications were introduced into the VIM low energy neutron transport code, representing the spatial and energy distributions of the source neutrons approximately as those of evaporation neutrons generated through the spallation process by protons of various energies. The intensity of slow neutrons leaking from various reflected moderators was studied for various neutron source arrangements. These include computations relating to early measurements on a mockup-assembly, a brief survey of moderator materials and sizes, and a survey of the effects of varying source and moderator configurations with a practical, liquid metal cooled uranium source Wing and slab, i.e., tangential and radial moderator arrangements, and Be vs CH2 reflectors are compared. Results are also presented for several complicated geometries which more closely represent realistic arrangements for a practical source, and for a subcritical fission multiplier such as might be driven by an electron linac. An adaptation of the code was developed to enable time dependent calculations, and investigated the effects of the reflector, decoupling and void liner materials on the pulse shape

  17. Activity report of the fusion neutronics source from April 1, 2001 to March 31, 2004

    International Nuclear Information System (INIS)

    The Fusion Neutronics Source (FNS) is an accelerator based 14 MeV neutron generator established in 1981. FNS is a powerful tool for neutronics research aiming the fusion reactor development such as neutron cross section measurements, integral experiments and blanket neutronics experiments. This report reviews the FNS activities in the period from April 1, 2001 to March 31, 2004, including collaboration with universities and other research institutes. The 35 papers are indexed individually. (J.P.N.)

  18. Intense neutron sources for cancer treatment

    International Nuclear Information System (INIS)

    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

  19. Neutronic studies of the coupled moderators for spallation neutron sources

    Institute of Scientific and Technical Information of China (English)

    Yin Wen; Liang Jiu-Qing

    2005-01-01

    We investigate the neutronic performance of coupled moderators to be implemented in spallation neutron sources by Monte-Carlo simulation and give the slow neutron spectra for the cold and thermal moderators. CH4 moderator can provide slow neutrons with highly desirable characteristics and will be used in low-power spallation neutron soureces. The slow neutron intensity extracted from different angles has been calculated. The capability of moderation of liquid H2 is lower than H2O and liquid CH4 due to lower atomic number density of hydrogen but we can compensate for this disadvantage by using a premoderator. The H2O premoderator of 2cm thickness can reduce the heat deposition in the cold moderator by about 33% without spoiling the neutron pulse.

  20. PGNAA neutron source moderation setup optimization

    CERN Document Server

    Zhang, Jinzhao

    2013-01-01

    Monte Carlo simulations were carried out to design a prompt {\\gamma}-ray neutron activation analysis (PGNAA) thermal neutron output setup using MCNP5 computer code. In these simulations the moderator materials, reflective materials and structure of the PGNAA 252Cf neutrons of thermal neutron output setup were optimized. Results of the calcuations revealed that the thin layer paraffin and the thick layer of heavy water moderated effect is best for 252Cf neutrons spectrum. The new design compared with the conventional neutron source design, the thermal neutron flux and rate were increased by 3.02 times and 3.27 times. Results indicate that the use of this design should increase the neutron flux of prompt gamma-ray neutron activation analysis significantly.

  1. Materials and neutronic research at the Low Energy Neutron Source

    Science.gov (United States)

    Baxter, David V.

    2016-04-01

    In the decade since the Low Energy Neutron Source (LENS) at Indiana University Center for Exploration of Energy and Matter (CEEM) produced its first neutrons, the facility has made important contributions to the international neutron scattering community. LENS employs a 13MeV proton beam at up to 4kW beam power onto one of two Be targets to produce neutrons for research in fields ranging from radiation effects in electronics to studies of the structure of fluids confined in nanoporous materials. The neutron source design at the heart of LENS facilitates relatively rapid hands-on access to most of its components which provides a foundation for a research program in experimental neutronics and affords numerous opportunities for novel educational experiences. We describe in some detail a number of the unique capabilities of this facility.

  2. The Spallation Neutron Source A Powerful Tool for Materials Research

    CERN Document Server

    Mason, Thomas E; Crawford, R K; Herwig, K W; Klose, F; Ankner, J F

    2005-01-01

    The wavelengths and energies of thermal and cold neutrons are ideally matched to the length and energy scales in the materials that underpin technologies of the present and future: ranging from semiconductors to magnetic devices, composites to biomaterials and polymers. The Spallation Neutron Source (SNS) will use an accelerator to produce the most intense beams of neutrons in the world when it is complete at the end of 2005. The project is being built by a collaboration of six U.S. Department of Energy laboratories. It will serve a diverse community of users drawn from academia, industry, and government labs with interests in condensed matter physics, chemistry, engineering materials, biology, and beyond.

  3. Neutron spin echo spectroscopy on the spallation neutron source

    International Nuclear Information System (INIS)

    An investigation has been made into the practicability of combining the neutron spin echo and time-of-flight techniques on the Rutherford Laboratory Spallation Neutron Source. Preliminary specifications are presented for a quasielastic instrument with an energy resolution down to approximately 10 neV and an inelastic spectrometer for measuring excitation widths approximately 1 μ eV. (author)

  4. (International Collaboration on Advanced Neutron Sources)

    Energy Technology Data Exchange (ETDEWEB)

    Hayter, J.B.

    1990-11-08

    The International Collaboration on Advanced Neutron Sources was started about a decade ago with the purpose of sharing information throughout the global neutron community. The collaboration has been extremely successful in optimizing the use of resources, and the discussions are open and detailed, with reasons for failure shared as well as reasons for success. Although the meetings have become increasingly oriented toward pulsed neutron sources, many of the neutron instrumentation techniques, such as the development of better monochromators, fast response detectors and various data analysis methods, are highly relevant to the Advanced Neutron Source (ANS). I presented one paper on the ANS, and another on the neutron optical polarizer design work which won a 1989 R D-100 Award. I also gained some valuable design ideas, in particular for the ANS hot source, in discussions with individual researchers from Canada, Western Europe, and Japan.

  5. Neutron Sources for Standard-Based Testing

    Energy Technology Data Exchange (ETDEWEB)

    Radev, Radoslav [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McLean, Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-11-10

    The DHS TC Standards and the consensus ANSI Standards use 252Cf as the neutron source for performance testing because its energy spectrum is similar to the 235U and 239Pu fission sources used in nuclear weapons. An emission rate of 20,000 ± 20% neutrons per second is used for testing of the radiological requirements both in the ANSI standards and the TCS. Determination of the accurate neutron emission rate of the test source is important for maintaining consistency and agreement between testing results obtained at different testing facilities. Several characteristics in the manufacture and the decay of the source need to be understood and accounted for in order to make an accurate measurement of the performance of the neutron detection instrument. Additionally, neutron response characteristics of the particular instrument need to be known and taken into account as well as neutron scattering in the testing environment.

  6. Dosimetry and fast neutron energies characterization of photoneutrons produced in some medical linear accelerators

    Science.gov (United States)

    Khaled, N. E.; Attalla, E. M.; Ammar, H.; Khalil, W.

    2011-12-01

    This work focusses on the estimation of induced photoneutrons energy, fluence, and strength using nuclear track detector (NTD) (CR-39). Photoneutron energy was estimated for three different linear accelerators, LINACs as an example for the commonly used accelerators. For high-energy linear accelerators, neutrons are produced as a consequence of photonuclear reactions in the target nuclei, accelerator head, field-flattening filters and beam collimators, and other irradiated objects. NTD (CR-39) is used to evaluate energy and fluence of the fast neutron. Track length is used to estimate fast photoneutrons energy for linear accelerators (Elekta 10 MV, Elekta 15 MV, and Varian 15 MV). Results show that the estimated neutron energies for the three chosen examples of LINACs reveals neutron energies in the range of 1-2 MeV for 10 and 15 MV X-ray beams. The fluence of neutrons at the isocenter (Φtotal) is found to be (4×106 n cm2 Gy-1) for Elekta machine 10 MV. The neutron source strengths Q are calculated. It was found to be 0.2×1012 n Gy-1 X-ray at the isocenter. This work represents simple, low cost, and accurate methods of measuring fast neutrons dose and energies.

  7. Proposal for a New Integrated Circuit and Electronics Neutron Experiment Source at Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Ferguson, Phillip D [ORNL

    2009-01-01

    Government and customer specifications increasingly require assessments of the single event effects probability in electronics from atmospheric neutrons. The accelerator that best simulates this neutron spectrum is the WNR facility (Los Alamos), but it is underfunded and oversubscribed for present and future needs. A new beam-line is proposed at the Oak Ridge National Laboratory, as part of the Spallation Neutron Source (SNS).

  8. Nested Focusing Optics for Compact Neutron Sources

    Science.gov (United States)

    Nabors, Sammy A.

    2015-01-01

    NASA's Marshall Space Flight Center, the Massachusetts Institute of Technology (MIT), and the University of Alabama Huntsville (UAH) have developed novel neutron grazing incidence optics for use with small-scale portable neutron generators. The technology was developed to enable the use of commercially available neutron generators for applications requiring high flux densities, including high performance imaging and analysis. Nested grazing incidence mirror optics, with high collection efficiency, are used to produce divergent, parallel, or convergent neutron beams. Ray tracing simulations of the system (with source-object separation of 10m for 5 meV neutrons) show nearly an order of magnitude neutron flux increase on a 1-mm diameter object. The technology is a result of joint development efforts between NASA and MIT researchers seeking to maximize neutron flux from diffuse sources for imaging and testing applications.

  9. New spallation neutron sources, their performance and applications

    International Nuclear Information System (INIS)

    Pulsed spallation sources now operating in the world are at the KEK Laboratory in Japan (the KENS source), at Los Alamos National Laboratory (WNR) and at Argonne National Laboratory (IPNS), both the latter being in the US. The Intense Pulsed Neutron Source (IPNS) is currently the world's most intense source with a peak neutron flux of 4 x 1014 n cm-2s-1 at a repetition rate of 30 Hz, and globally producing approx. 1.5 x 1015 n/sec. Present pulsed sources are still relatively weak compared to their potential. In 1985 the Rutherford Spallation Neutron Source will come on line, and eventually be approx. 30 more intense than the present IPNS. Later, in 1986 the WNR/PSR option at Los Alamos will make that facility of comparable intensity, while a subcritical fission booster at IPNS will keep IPNS competitive. These new sources will expand the applications of pulsed neutrons but are still based on accelerators built for other scientific purposes, usually nuclear or high-energy physics. Accelerator physicists are now designing machines expressly for spallation neutron research, and the proton currents attainable appear in the milliamps. (IPNS now runs at 0.5 GeV and 14 μA). Such design teams are at the KFA Laboratory Julich, Argonne National Laboratory and KEK. Characteristics, particularly the different time structure of the pulses, of these new sources will be discussed. Such machines will be expensive and require national, if not international, collaboration across a wide spectrum of scientific disciplines. The new opportunities for neutron research will, of course, be dramatic with these new sources

  10. Neutron scattering instruments for the Spallation Neutron Source (SNS)

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, R.K.; Fornek, T. [Argonne National Lab., IL (United States); Herwig, K.W. [Oak Ridge National Lab., TN (United States)

    1998-07-01

    The Spallation Neutron Source (SNS) is a 1 MW pulsed spallation source for neutron scattering planned for construction at Oak Ridge National Laboratory. This facility is being designed as a 5-laboratory collaboration project. This paper addresses the proposed facility layout, the process for selection and construction of neutron scattering instruments at the SNS, the initial planning done on the basis of a reference set of ten instruments, and the plans for research and development (R and D) to support construction of the first ten instruments and to establish the infrastructure to support later development and construction of additional instruments.

  11. Neutron scattering instrumentation for biology at spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Pynn, R. [Los Alamos National Laboratory, NM (United States)

    1994-12-31

    Conventional wisdom holds that since biological entities are large, they must be studied with cold neutrons, a domain in which reactor sources of neutrons are often supposed to be pre-eminent. In fact, the current generation of pulsed spallation neutron sources, such as LANSCE at Los Alamos and ISIS in the United Kingdom, has demonstrated a capability for small angle scattering (SANS) - a typical cold- neutron application - that was not anticipated five years ago. Although no one has yet built a Laue diffractometer at a pulsed spallation source, calculations show that such an instrument would provide an exceptional capability for protein crystallography at one of the existing high-power spoliation sources. Even more exciting is the prospect of installing such spectrometers either at a next-generation, short-pulse spallation source or at a long-pulse spallation source. A recent Los Alamos study has shown that a one-megawatt, short-pulse source, which is an order of magnitude more powerful than LANSCE, could be built with today`s technology. In Europe, a preconceptual design study for a five-megawatt source is under way. Although such short-pulse sources are likely to be the wave of the future, they may not be necessary for some applications - such as Laue diffraction - which can be performed very well at a long-pulse spoliation source. Recently, it has been argued by Mezei that a facility that combines a short-pulse spallation source similar to LANSCE, with a one-megawatt, long-pulse spallation source would provide a cost-effective solution to the global shortage of neutrons for research. The basis for this assertion as well as the performance of some existing neutron spectrometers at short-pulse sources will be examined in this presentation.

  12. Ion Acceleration in Solar Flares Determined by Solar Neutron Observations

    Science.gov (United States)

    Watanabe, K.; Solar Neutron Observation Group

    2013-05-01

    Large amounts of particles can be accelerated to relativistic energy in association with solar flares and/or accompanying phenomena (e.g., CME-driven shocks), and they sometimes reach very near the Earth and penetrate the Earth's atmosphere. These particles are observed by ground-based detectors (e.g., neutron monitors) as Ground Level Enhancements (GLEs). Some of the GLEs originate from high energy solar neutrons which are produced in association with solar flares. These neutrons are also observed by ground-based neutron monitors and solar neutron telescopes. Recently, some of the solar neutron detectors have also been operating in space. By observing these solar neutrons, we can obtain information about ion acceleration in solar flares. Such neutrons were observed in association with some X-class flares in solar cycle 23, and sometimes they were observed by two different types of detectors. For example, on 2005 September 7, large solar neutron signals were observed by the neutron monitor at Mt. Chacaltaya in Bolivia and Mexico City, and by the solar neutron telescopes at Chacaltaya and Mt. Sierra Negra in Mexico in association with an X17.0 flare. The neutron signal continued for more than 20 minutes with high statistical significance. Intense gamma-ray emission was also registered by INTEGRAL, and by RHESSI during the decay phase. We analyzed these data using the solar-flare magnetic-loop transport and interaction model of Hua et al. (2002), and found that the model could successfully fit the data with intermediate values of loop magnetic convergence and pitch angle scattering parameters. These results indicate that solar neutrons were produced at the same time as the gamma-ray line emission and that ions were continuously accelerated at the emission site. In this paper, we introduce some of the solar neutron observations in solar cycle 23, and discuss the tendencies of the physical parameters of solar neutron GLEs, and the energy spectrum and population of the

  13. Neutron dosimetry with TL albedo dosemeters at high energy accelerators

    International Nuclear Information System (INIS)

    The GSF-Personal Monitoring Service uses the TLD albedo dosemeter as standard neutron personal dosemeter. Due to its low sensitivity for fast neutrons however, it is generally not recommended for workplaces at high-energy accelerators. Test measurements with the albedo dosemeter were performed at the accelerator laboratories of GSI in Darmstadt and DESY in Hamburg to reconsider this hypothesis. It revealed that the albedo dosemeter can also be used as personal dosemeter at these workplaces, because at all measurement locations a significant part of neutrons with lower energies could be found, which were produced by scattering at walls or the ground. (authors)

  14. Neutron dosimetry with TL albedo dosemeters at high energy accelerators.

    Science.gov (United States)

    Haninger, T; Fehrenbacher, G

    2007-01-01

    The GSF-Personal Monitoring Service uses the TLD albedo dosemeter as standard neutron personal dosemeter. Due to its low sensitivity for fast neutrons however, it is generally not recommended for workplaces at high-energy accelerators. Test measurements with the albedo dosemeter were performed at the accelerator laboratories of GSI in Darmstadt and DESY in Hamburg to reconsider this hypothesis. It revealed that the albedo dosemeter can also be used as personal dosemeter at these workplaces, because at all measurement locations a significant part of neutrons with lower energies could be found, which were produced by scattering at walls or the ground. PMID:17766258

  15. International workshop on cold neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Russell, G.J.; West, C.D. (comps.) (Los Alamos National Lab., NM (United States))

    1991-08-01

    The first meeting devoted to cold neutron sources was held at the Los Alamos National Laboratory on March 5--8, 1990. Cosponsored by Los Alamos and Oak Ridge National Laboratories, the meeting was organized as an International Workshop on Cold Neutron Sources and brought together experts in the field of cold-neutron-source design for reactors and spallation sources. Eighty-four people from seven countries attended. Because the meeting was the first of its kind in over forty years, much time was spent acquainting participants with past and planned activities at reactor and spallation facilities worldwide. As a result, the meeting had more of a conference flavor than one of a workshop. The general topics covered at the workshop included: Criteria for cold source design; neutronic predictions and performance; energy deposition and removal; engineering design, fabrication, and operation; material properties; radiation damage; instrumentation; safety; existing cold sources; and future cold sources.

  16. International workshop on cold neutron sources

    International Nuclear Information System (INIS)

    The first meeting devoted to cold neutron sources was held at the Los Alamos National Laboratory on March 5--8, 1990. Cosponsored by Los Alamos and Oak Ridge National Laboratories, the meeting was organized as an International Workshop on Cold Neutron Sources and brought together experts in the field of cold-neutron-source design for reactors and spallation sources. Eighty-four people from seven countries attended. Because the meeting was the first of its kind in over forty years, much time was spent acquainting participants with past and planned activities at reactor and spallation facilities worldwide. As a result, the meeting had more of a conference flavor than one of a workshop. The general topics covered at the workshop included: Criteria for cold source design; neutronic predictions and performance; energy deposition and removal; engineering design, fabrication, and operation; material properties; radiation damage; instrumentation; safety; existing cold sources; and future cold sources

  17. Radionuclide 252Cf neutron source

    International Nuclear Information System (INIS)

    Characteristics of radionuclide neutron sourses of 252Cf base with the activity from 106 to 109 n/s have been investigated. Energetic distributions of neutrons and gamma-radiation have been presented. The results obtained have been compared with other data available. The hardness parameter of the neutron spectrum for the energy range from 3 to 15 MeV is 1.4 +- 0.02 MeV

  18. Simplified neutron detector for angular distribution measurement of p-Li neutron source

    International Nuclear Information System (INIS)

    Boron Neutron Capture Therapy (BNCT) is one of the most promising cancer therapies using 10B(n, α)7Li nuclear reaction. Because nuclear reactor is currently used for BNCT, the therapy is much restricted. Many kinds of accelerator based neutron sources for BNCT are being investigated worldwide and p-Li reaction is one of the most promising candidates because the emitted neutron energy is comparatively low and no gamma-ray is produced. To use p-Li neutron source for BNCT, measurement of the angular distribution is important. However, the energy of neutrons changes depending on the angle with respect to the proton beam, e.g., the energy of forward emitted neutrons are about 700 keV and it is 100 keV for backward direction. So a neutron detector, the efficiency of which is not dependent on energy, is needed. Though so-called “Long Counter” is known to be available, its structure is complicated and moreover it is expensive. Thus we have designed and developed a simplified neutron detector using Monte Carlo simulation. We verified the developed detector experimentally and measured the angular distribution in detail for p-Li reaction by using it. The obtained results were compared with analytical calculations. (author)

  19. Improved Actinide Neutron Capture Cross Sections Using Accelerator Mass Spectrometry

    Science.gov (United States)

    Bauder, W.; Pardo, R. C.; Kondev, F. G.; Kondrashev, S.; Nair, C.; Nusair, O.; Palchan, T.; Scott, R.; Seweryniak, D.; Vondrasek, R.; Collon, P.; Paul, M.; Youinou, G.; Salvatores, M.; Palmotti, G.; Berg, J.; Maddock, T.; Imel, G.

    2014-09-01

    The MANTRA (Measurement of Actinide Neutron TRAnsmutations) project will improve energy-integrated neutron capture cross section data across the actinide region. These data are incorporated into nuclear reactor models and are an important piece in understanding Generation IV reactor designs. We will infer the capture cross sections by measuring isotopic ratios from actinide samples, irradiated in the Advanced Test Reactor at INL, with Accelerator Mass Spectrometry (AMS) at ATLAS (ANL). The superior sensitivity of AMS allows us to extract multiple cross sections from a single sample. In order to analyze the large number of samples needed for MANTRA and to meet the goal of extracting multiple cross sections per sample, we have made a number of modifications to the AMS setup at ATLAS. In particular, we are developing a technique to inject solid material into the ECR with laser ablation. With laser ablation, we can better control material injection and potentially increase efficiency in the ECR, thus creating less contamination in the source and reducing cross talk. I will present work on the laser ablation system and preliminary results from our AMS measurements. The MANTRA (Measurement of Actinide Neutron TRAnsmutations) project will improve energy-integrated neutron capture cross section data across the actinide region. These data are incorporated into nuclear reactor models and are an important piece in understanding Generation IV reactor designs. We will infer the capture cross sections by measuring isotopic ratios from actinide samples, irradiated in the Advanced Test Reactor at INL, with Accelerator Mass Spectrometry (AMS) at ATLAS (ANL). The superior sensitivity of AMS allows us to extract multiple cross sections from a single sample. In order to analyze the large number of samples needed for MANTRA and to meet the goal of extracting multiple cross sections per sample, we have made a number of modifications to the AMS setup at ATLAS. In particular, we are

  20. rf improvements for Spallation Neutron Source H-ion source

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Yoon W [ORNL; Fuja, Raymond E [ORNL; Goulding, Richard Howell [ORNL; Hardek, Thomas W [ORNL; Lee, Sung-Woo [ORNL; McCarthy, Mike [ORNL; Piller, Chip [ORNL; Shin, Ki [ORNL; Stockli, Martin P [ORNL; Welton, Robert F [ORNL

    2010-01-01

    The Spallation Neutron Source at Oak Ridge National Laboratory is ramping up the accelerated proton beam power to 1.4 MW and just reached 1 MW. The rf-driven multicusp ion source that originates from the Lawrence Berkeley National Laboratory has been delivering 38 mA H beam in the linac at 60 Hz, 0.9 ms. To improve availability, a rf-driven external antenna multicusp ion source with a water-cooled ceramic aluminum nitride AlN plasma chamber is developed. Computer modeling and simulations have been made to analyze and optimize the rf performance of the new ion source. Operational statistics and test runs with up to 56 mA medium energy beam transport beam current identify the 2 MHz rf system as a limiting factor in the system availability and beam production. Plasma ignition system is under development by using a separate 13 MHz system. To improve the availability of the rf power system with easier maintenance, we tested a 70 kV isolation transformer for the 80 kW, 6% duty cycle 2 MHz amplifier to power the ion source from a grounded solid-state amplifier. 2010 American Institute of Physics.

  1. Detection of Neutron Sources in Cargo Containers

    OpenAIRE

    Katz, J. I.

    2007-01-01

    We investigate the problem of detecting the presence of clandestine neutron sources, such as would be produced by nuclear weapons containing plutonium, within cargo containers. Small, simple and economical semiconductor photodiode detectors affixed to the outsides of containers are capable of producing statistically robust detections of unshielded sources when their output is integrated over the durations of ocean voyages. It is possible to shield such sources with thick layers of neutron-abs...

  2. Advanced Neutron Source (ANS) Project progress report

    International Nuclear Information System (INIS)

    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

  3. Advanced Neutron Source (ANS) Project progress report

    Energy Technology Data Exchange (ETDEWEB)

    McBee, M.R.; Chance, C.M. (eds.) (Oak Ridge National Lab., TN (USA)); Selby, D.L.; Harrington, R.M.; Peretz, F.J. (Oak Ridge National Lab., TN (USA))

    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 C research and development; facility concepts; design; and safety.

  4. The University of Texas Cold Neutron Source

    Science.gov (United States)

    Ünlü, Kenan; Ríos-Martínez, Carlos; Wehring, Bernard W.

    1994-12-01

    A cold neutron source has been designed, constructed, and tested by the Nuclear Engineering Teaching Laboratory (NETL) at The University of Texas at Austin. The Texas Cold Neutron Source (TCNS) is located in one of the beam ports of the NETL 1-MW TRIGA Mark II research reactor. The main components of the TCNS are a cooled moderator, a heat pipe, a cryogenic refrigerator, and a neutron guide. 80 ml of mesitylene moderator are maintained at about 30 K in a chamber within the reactor graphite reflector by the heat pipe and cryogenic refrigerator. The heat pipe is a 3-m long aluminum tube that contains neon as the working fluid. The cold neutrons obtained from the moderator are transported by a curved 6-m long neutron guide. This neutron guide has a radius of curvature of 300 m, a 50 × 15 mm cross-section, 58Ni coating, and is separated into three channels. The TCNS will provide a low-background subthermal neutron beam for neutron capture and scattering research. After the installation of the external portion of the neutron guide, a neutron focusing system and a Prompt Gamma Activation Analysis facility will be set up at the TCNS.

  5. Characteristics comparison between a cyclotron-based neutron source and KUR-HWNIF for boron neutron capture therapy

    Science.gov (United States)

    Tanaka, H.; Sakurai, Y.; Suzuki, M.; Masunaga, S.; Kinashi, Y.; Kashino, G.; Liu, Y.; Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Maruhashi, A.; Ono, K.

    2009-06-01

    At Kyoto University Research Reactor Institute (KURRI), 275 clinical trials of boron neutron capture therapy (BNCT) have been performed as of March 2006, and the effectiveness of BNCT has been revealed. In order to further develop BNCT, it is desirable to supply accelerator-based epithermal-neutron sources that can be installed near the hospital. We proposed the method of filtering and moderating fast neutrons, which are emitted from the reaction between a beryllium target and 30-MeV protons accelerated by a cyclotron accelerator, using an optimum moderator system composed of iron, lead, aluminum and calcium fluoride. At present, an epithermal-neutron source is under construction from June 2008. This system consists of a cyclotron accelerator, beam transport system, neutron-yielding target, filter, moderator and irradiation bed. In this article, an overview of this system and the properties of the treatment neutron beam optimized by the MCNPX Monte Carlo neutron transport code are presented. The distribution of biological effect weighted dose in a head phantom compared with that of Kyoto University Research Reactor (KUR) is shown. It is confirmed that for the accelerator, the biological effect weighted dose for a deeply situated tumor in the phantom is 18% larger than that for KUR, when the limit dose of the normal brain is 10 Gy-eq. The therapeutic time of the cyclotron-based neutron sources are nearly one-quarter of that of KUR. The cyclotron-based epithermal-neutron source is a promising alternative to reactor-based neutron sources for treatments by BNCT.

  6. Acceleration and deceleration of neutrons: From the phase modulation of a neutron wave to a neutron turbine with refracting prisms

    International Nuclear Information System (INIS)

    The possibility of the acceleration and deceleration of neutrons undergoing diffraction at a moving grating is discussed. It is shown that, in contrast to phase π gratings used at the present time, which form a discrete spectrum featuring a large number of lines, a grating that has a special profile may shift, under certain conditions, the entire spectrum of diffracted neutrons. A blazing grating of this type may be used in efficiently accelerating and decelerating neutrons. As the scale of the structure becomes larger, a description based on the idea of neutron-wave refraction at its elements becomes valid, a system of moving prims forming a “neutron turbine,” which is also able to accelerate or decelerate neutrons, being a classical limit of this enlargement.

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

    International Nuclear Information System (INIS)

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

  8. 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)

  9. Neutron source structure for nuclear reactors

    International Nuclear Information System (INIS)

    Purpose: To improve the compatibility between metal beryllium forming a neutron source and a metal cladding material at a high temperature. Constitution: An intermediate layer made of silicon or silicone-beryllium alloy is put between metal beryllium forming a neutron source and a metal cladding material containing the metal beryllium in a tightly sealed manner. By the disposition of the intermediate layer, the compatibility between the metal beryllium and the metal cladding material is improved, by which the neutron source can be operated satisfactorily over a long time use at a high temperature of 500 - 7000C. (Moriyama, K.)

  10. Optimization of a neutron transmission beamline applied to materials science for the CAB linear accelerator

    International Nuclear Information System (INIS)

    The Neutrons and Reactors Laboratory (NYR) of CAB (Centro Atomico Bariloche) is equipped with a linear electron accelerator (LINAC - Linear particle accelerator). This LINAC is used as a neutron source from which two beams are extracted to perform neutron transmission and dispersion experiments. Through these experiments, structural and dynamic properties of materials can be studied. The neutron transmission experiments consist in a collimated neutron beam which interacts with a sample and a detector behind the sample. Important information about the microstructural characteristics of the material can be obtained from the comparison between neutron spectra before and after the interaction with the sample. In the NYR Laboratory, cylindrical samples of one inch of diameter have been traditionally studied. Nonetheless, there is a great motivation for doing systematic research on smaller and with different geometries samples; particularly sheets and samples for tensile tests. Hence, in the NYR Laboratory it has been considered the possibility of incorporating a neutron guide into the existent transmission line. According to all mentioned above, the main objective of this work consisted in the optimization of the flight transmission tube optics of neutrons. This optimization not only improved the existent line but also contributed to an election criterion for the neutron guide acquisition.

  11. Accelerator-based neutron tomography cooperating with X-ray radiography

    International Nuclear Information System (INIS)

    Neutron resonance absorption spectroscopy (N-RAS) using a pulsed neutron source can be applied to time-of-flight (TOF) radiography, and the obtained parameters from the peak shape analysis can be reconstructed as the tomograms of nuclide distributions using computed tomography (CT). The problem is that the available spatial resolution is not sufficient for radiography imaging. In this study, we combined neutron and X-ray radiographies to improve the quantitative reconstruction of the neutron tomogram. The accelerator-based neutron source emits X-rays (or gamma-rays) at the same time the neutron pulse is emitted. We utilized the X-ray beam from the neutron source to obtain X-ray radiogram on the same beam line with neutron radiography and then reconstructed the neutron tomogram quantitatively with the help of a detailed sample internal structure obtained from the X-ray radiogram. We calculated the nuclide number density distribution tomogram using a statistical reconstruction procedure, which was easy to include in the structure model during the reconstruction. The obtained result of nuclide number density distribution showed good coincidence with the original object number density.

  12. Experimental investigations of the neutron contamination in high-energy photon fields at medical linear accelerators

    International Nuclear Information System (INIS)

    The scope of this thesis was to develop a device for the detection of the photoneutron dose inside the high-energy photon field. The photoneutron contamination of a Siemens PRIMUS linear accelerator was investigated in detail in its 15 MV photon mode. The experimental examinations were performed with three ionisation chambers (a tissue equivalent chamber, a magnesium chamber and a 10B-coated magnesium chamber) and two types of thermoluminescence detectors (enriched with 6Li and 7Li, respectively). The detectors have different sensitivities to photons and neutrons and their combination allows the dose separation in a mixed neutron/photon field. The application of the ionisation chamber system, as well as the present TLD system for photoneutron detection in high-energy photon beams is a new approach. The TLD neutron sensitivity was found to be too low for a measurement inside the open photon field and the further investigation focused on the ionisation chambers. The three ionisation chambers were calibrated at different photon and neutron sources and a the borated magnesium chamber showed a very high response to thermal neutrons. For a cross check of the calibration, the three chambers were also used for dose separation of a boron neutron capture therapy beam where the exact determination of the thermal neutron dose is essential. Very accurate results were achieved for the thermal neutron dose component. At the linear accelerator the chamber system was reduced to a paired chamber system utilising the two magnesium chambers, since the fast neutron component was to small to be separated. The neutron calibration of the three chambers could not be applied, instead a conversion of measured thermal neutron signal by the borated chamber to Monte Carlo simulated total neutron dose was performed. Measurements for open fields in solid water and liquid water were performed with the paired chamber system. In larger depths the neutron dose could be determined with an uncertainty

  13. Experimental investigations of the neutron contamination in high-energy photon fields at medical linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Brunckhorst, Elin

    2009-02-26

    The scope of this thesis was to develop a device for the detection of the photoneutron dose inside the high-energy photon field. The photoneutron contamination of a Siemens PRIMUS linear accelerator was investigated in detail in its 15 MV photon mode. The experimental examinations were performed with three ionisation chambers (a tissue equivalent chamber, a magnesium chamber and a {sup 10}B-coated magnesium chamber) and two types of thermoluminescence detectors (enriched with {sup 6}Li and {sup 7}Li, respectively). The detectors have different sensitivities to photons and neutrons and their combination allows the dose separation in a mixed neutron/photon field. The application of the ionisation chamber system, as well as the present TLD system for photoneutron detection in high-energy photon beams is a new approach. The TLD neutron sensitivity was found to be too low for a measurement inside the open photon field and the further investigation focused on the ionisation chambers. The three ionisation chambers were calibrated at different photon and neutron sources and a the borated magnesium chamber showed a very high response to thermal neutrons. For a cross check of the calibration, the three chambers were also used for dose separation of a boron neutron capture therapy beam where the exact determination of the thermal neutron dose is essential. Very accurate results were achieved for the thermal neutron dose component. At the linear accelerator the chamber system was reduced to a paired chamber system utilising the two magnesium chambers, since the fast neutron component was to small to be separated. The neutron calibration of the three chambers could not be applied, instead a conversion of measured thermal neutron signal by the borated chamber to Monte Carlo simulated total neutron dose was performed. Measurements for open fields in solid water and liquid water were performed with the paired chamber system. In larger depths the neutron dose could be determined

  14. The high intensity neutron source FRANZ

    CERN Document Server

    Lederer, Claudia

    2014-01-01

    The Frankfurt neutron source of Stern Gerlach Zentrum FRANZ is currently under construction at the University of Frankfurt. At FRANZ, a high intensity neutron beam in the keV energy region will be produced by bombarding a $^7$Li target with a proton beam of several mA. These unprecedented high neutron fluxes will allow a number of neutron induced cross section measurements for the first time. Measurements can be performed by the time-of-flight and by the activation technique.

  15. BNL Activities in Advanced Neutron Source Development: Past and Present

    Energy Technology Data Exchange (ETDEWEB)

    Hastings, J.B.; Ludewig, H.; Montanez, P.; Todosow, M.; Smith, G.C.; Larese, J.Z.

    1998-06-14

    Brookhaven National Laboratory has been involved in advanced neutron sources almost from its inception in 1947. These efforts have mainly focused on steady state reactors beginning with the construction of the first research reactor for neutron beams, the Brookhaven Graphite Research Reactor. This was followed by the High Flux Beam Reactor that has served as the design standard for all the subsequent high flux reactors constructed worldwide. In parallel with the reactor developments BNL has focused on the construction and use of high energy proton accelerators. The first machine to operate over 1 GeV in the world was the Cosmotron. The machine that followed this, the AGS, is still operating and is the highest intensity proton machine in the world and has nucleated an international collaboration investigating liquid metal targets for next generation pulsed spallation sources. Early work using the Cosmotron focused on spallation product studies for both light and heavy elements into the several GeV proton energy region. These original studies are still important today. In this report we discuss the facilities and activities at BNL focused on advanced neutron sources. BNL is involved in the proton source for the Spallation Neutron source, spectrometer development at LANSCE, target studies using the AGS and state-of-the-art neutron detector development.

  16. BNL ACTIVITIES IN ADVANCED NEUTRON SOURCE DEVELOPMENT: PAST AND PRESENT

    Energy Technology Data Exchange (ETDEWEB)

    HASTINGS,J.B.; LUDEWIG,H.; MONTANEZ,P.; TODOSOW,M.; SMITH,G.C.; LARESE,J.Z.

    1998-06-14

    Brookhaven National Laboratory has been involved in advanced neutron sources almost from its inception in 1947. These efforts have mainly focused on steady state reactors beginning with the construction of the first research reactor for neutron beams, the Brookhaven Graphite Research Reactor. This was followed by the High Flux Beam Reactor that has served as the design standard for all the subsequent high flux reactors constructed worldwide. In parallel with the reactor developments BNL has focused on the construction and use of high energy proton accelerators. The first machine to operate over 1 GeV in the world was the Cosmotron. The machine that followed this, the AGS, is still operating and is the highest intensity proton machine in the world and has nucleated an international collaboration investigating liquid metal targets for next generation pulsed spallation sources. Early work using the Cosmotron focused on spallation product studies for both light and heavy elements into the several GeV proton energy region. These original studies are still important today. In the sections below the authors discuss the facilities and activities at BNL focused on advanced neutron sources. BNL is involved in the proton source for the Spallation Neutron source, spectrometer development at LANSCE, target studies using the AGS and state-of-the-art neutron detector development.

  17. Proceedings of the fifteenth meeting of the international collaboration on advanced neutron sources (ICANS-XV). Advanced neutron sources towards the next century

    International Nuclear Information System (INIS)

    The fifteenth meeting of the International Collaboration on Advanced Neutron Sources (ICANS-XV) was held at Epocal Tsukuba, International Congress Center on 6-9 November 2000. It was hosted by Japan Atomic Energy Research Institute (JAERI) and High Energy Accelerator Research Organization (KEK). This meeting focused on 'Neutron Sources toward the 21st Century' and research activities related to targets and moderators, neutron scattering instruments and accelerators were presented. The 151 of the presented papers are indexed individually. (J.P.N.)

  18. Proceedings of the fifteenth meeting of the international collaboration on advanced neutron sources (ICANS-XV). Advanced neutron sources towards the next century

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Jun-ichi [Center for Neutron Science, Tokai Research Establishment, Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan); Itoh, Shinichi [Neutron Science Laboratory, High Energy Accelerator Research Organization, Tsukuba, Ibaraki (JP)] (eds.)

    2001-03-01

    The fifteenth meeting of the International Collaboration on Advanced Neutron Sources (ICANS-XV) was held at Epocal Tsukuba, International Congress Center on 6-9 November 2000. It was hosted by Japan Atomic Energy Research Institute (JAERI) and High Energy Accelerator Research Organization (KEK). This meeting focused on 'Neutron Sources toward the 21st Century' and research activities related to targets and moderators, neutron scattering instruments and accelerators were presented. The 151 of the presented papers are indexed individually. (J.P.N.)

  19. High Brightness Neutron Source for Radiography

    Energy Technology Data Exchange (ETDEWEB)

    Cremer, J. T.; Piestrup, Melvin, A.; Gary, Charles, K.; Harris, Jack, L. Williams, David, J.; Jones, Glenn, E.; Vainionpaa, J. , H.; Fuller, Michael, J.; Rothbart, George, H.; Kwan, J., W.; Ludewigt, B., A.; Gough, R.., A..; Reijonen, Jani; Leung, Ka-Ngo

    2008-12-08

    This research and development program was designed to improve nondestructive evaluation of large mechanical objects by providing both fast and thermal neutron sources for radiography. Neutron radiography permits inspection inside objects that x-rays cannot penetrate and permits imaging of corrosion and cracks in low-density materials. Discovering of fatigue cracks and corrosion in piping without the necessity of insulation removal is possible. Neutron radiography sources can provide for the nondestructive testing interests of commercial and military aircraft, public utilities and petrochemical organizations. Three neutron prototype neutron generators were designed and fabricated based on original research done at the Lawrence Berkeley National Laboratory (LBNL). The research and development of these generators was successfully continued by LBNL and Adelphi Technology Inc. under this STTR. The original design goals of high neutron yield and generator robustness have been achieved, using new technology developed under this grant. In one prototype generator, the fast neutron yield and brightness was roughly 10 times larger than previously marketed neutron generators using the same deuterium-deuterium reaction. In another generator, we integrate a moderator with a fast neutron source, resulting in a high brightness thermal neutron generator. The moderator acts as both conventional moderator and mechanical and electrical support structure for the generator and effectively mimics a nuclear reactor. In addition to the new prototype generators, an entirely new plasma ion source for neutron production was developed. First developed by LBNL, this source uses a spiral antenna to more efficiently couple the RF radiation into the plasma, reducing the required gas pressure so that the generator head can be completely sealed, permitting the possible use of tritium gas. This also permits the generator to use the deuterium-tritium reaction to produce 14-MeV neutrons with increases

  20. Neutronic performance issues for the Spallation Neutron Source moderators

    Energy Technology Data Exchange (ETDEWEB)

    Iverson, E.B.; Murphy, B.D. [Oak Ridge National Laboratory, Spallation Neutron Source, Oak Ridge, TN (United States)

    2001-03-01

    We continue to develop the neutronic models of the Spallation Neutron Source target station and moderators in order to better predict the neutronic performance of the system as a whole and in order to better optimize that performance. While we are not able to say that every model change leads to more intense neutron beams being predicted, we do feel that such changes are advantageous in either performance or in the accuracy of the prediction of performance. We have computationally and experimentally studied the neutronics of hydrogen-water composite moderators such as are proposed for the SNS Project. In performing these studies, we find that the composite moderator, at least in the configuration we have examined, does not provide performance characteristics desirable for the instruments proposed and being designed for this neutron scattering facility. The pulse width as a function of energy is significantly broader than for other moderators, limiting attainable resolution-bandwidth combinations. Furthermore, there is reason to expect that higher-energy (0.1-1 eV) applications will be significantly impacted by bimodal pulse shapes requiring enormous effort to parameterize. As a result of these studies, we have changed the SNS design, and will not use a composite moderator at this time. We have analyzed the depletion of a gadolinium poison plate in a hydrogen moderator at the Spallation Neutron Source, and found that conventional poison thicknesses will be completely unable to last the desired component lifetime of three operational years. A poison plate 300-600 {mu}m thick will survive for the required length of time, but will somewhat degrade the intensity (by as much as 15% depending on neutron energy) and the consistency of the neutron source performance. Our results should scale fairly easily to other moderators on this or any other spallation source. While depletion will be important for all highly-absorbing materials in high-flux regions, we feel it likely

  1. Targets for neutron beam spallation sources

    International Nuclear Information System (INIS)

    The meeting on Targets for Neutron Beam Spallation Sources held at the Institut fuer Festkoerperforschung at KFA Juelich on June 11 and 12, 1979 was planned as an informal get-together for scientists involved in the planning, design and future use of spallation neutron sources in Europe. These proceedings contain the papers contributed to this meeting. For further information see hints under relevant topics. (orig./FKS)

  2. The Brazilian status on ADS R and D: Preliminary road map to a program on accelerator utilization on basic and applied nuclear physics, products and services and to drive an experimental neutron source sub critical facility

    International Nuclear Information System (INIS)

    the activities already underway in Nuclear Physics and Engineering, and preserves the identities and focus of the various institutions involved. ADS related research and development is being pursued by IPEN (design calculation, development of an Alternative Concept for a Fast Energy Amplifier). Moreover, IPEN operates a small cyclotrons, CV-28. The IPEN CV-28 cyclotron is presently not operational, but suitable for R and D: it is a compact, isochronous, multi-particle radiation source where protons, deuterons, 3He++, and alpha particles can be accelerated with variable energies up to 24, 14, 36, and 28 MeV respectively. Finally, IPEN is also operating the Cyclone-30 from IBA which is dedicated to radioisotope production (201-Tl, 123-I, 67-Ga), an electron accelerator used in high social and economic impact projects (e.g., food irradiation), and a Van de Graaff capable to provide a 14 MeV neutron source. The Physics Institute of Sao Paulo University-IFUSP is implementing various R and D activities/projects, in areas such as nuclear reactions with heavy ions, nuclear structure, photo nuclear reactions, ion implantation, non destructive techniques using accelerators beams. These programs are centered on IFUSP facilities, i.e., a heavy ion electrostatic accelerator (PELLETRON), a linear accelerator (LINAC), and an electron accelerator (MICROTRON), as well as associated experimental facilities. The institute is also performing theoretical research on nuclear reactions of interest to ADS (spallation-cascade evaporation model). Given the outlined scenario, IPEN-IFUSP have identified the possibility to launch a program on the utilization of accelerators. This programs would have three main pillars: R and D in basic and applied nuclear physics and engineering (e.g., low energy cross sections nuclear reactions, charged particle activation analysis, hydrogen implantation for angular correlation studies, excitation function determination, helium embrittlement in structural

  3. A study of neutron output from a medical linear accelerator

    International Nuclear Information System (INIS)

    In recent years, medical linear accelerators of higher energies (E>10 MeV) are becoming of common use in Brazil and the National Nuclear Energy Commission (CNEN) is facing the problem of licensing these Radiative Facilities. The question of how to shield these rooms, considering the neutron output from these machines, is not trivial. Many empirical models suggest how to calculate the neutron dose equivalent due to these particles, which are mainly produced trough (g,n) reactions in the accelerator head. In this article we present some measurements of neutrons produced by a 18 MeV Varian CLINAC 2100C linear accelerator at the Albert Einstein Hospital, in Sao Paulo, Brazil. The results are compared with theoretical calculations based on empirical models as well as on the equations presented in NCRP 79. (author)

  4. The intense neutron generator and future factory type ion accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, W.B

    1968-07-01

    A neutron factory is likely to sell its product in the form of isotopes. To ay neutron factories are nuclear reactors. Ion accelerators may also produce isotopes by direct interaction and, at high enough energies, mesons and hyperons. The challenge of the electrical production of neutrons goes far beyond the isotope market. It challenges the two popular concepts for long term large scale energy, the fast breeder reactor and controlled thermonuclear fusion. For this use about 4% of nuclear generated power would be applied in a feedback loop generating extra neutrons. Competition rests on operating and processing costs. The Intense Neutron Generator proposal now cancelled would have been full scale for such a use, but much further advance in accelerator engineering is required and anticipated. Perhaps most promising is the application of the ion drag principle in which rings of fast electrons are accelerated along their axis dragging ions with them by electrostatic attraction. Due to the much larger mass of the ions they can acquire much higher energy than the electrons and the process could be efficient. Such accelerators have not yet been made but experimental and theoretical studies are promising. (author)

  5. The intense neutron generator and future factory type ion accelerators

    International Nuclear Information System (INIS)

    A neutron factory is likely to sell its product in the form of isotopes. To ay neutron factories are nuclear reactors. Ion accelerators may also produce isotopes by direct interaction and, at high enough energies, mesons and hyperons. The challenge of the electrical production of neutrons goes far beyond the isotope market. It challenges the two popular concepts for long term large scale energy, the fast breeder reactor and controlled thermonuclear fusion. For this use about 4% of nuclear generated power would be applied in a feedback loop generating extra neutrons. Competition rests on operating and processing costs. The Intense Neutron Generator proposal now cancelled would have been full scale for such a use, but much further advance in accelerator engineering is required and anticipated. Perhaps most promising is the application of the ion drag principle in which rings of fast electrons are accelerated along their axis dragging ions with them by electrostatic attraction. Due to the much larger mass of the ions they can acquire much higher energy than the electrons and the process could be efficient. Such accelerators have not yet been made but experimental and theoretical studies are promising. (author)

  6. Evaluation of thermal neutron irradiation field using a cyclotron-based neutron source for alpha autoradiography

    International Nuclear Information System (INIS)

    It is important to measure the microdistribution of 10B in a cell to predict the cell-killing effect of new boron compounds in the field of boron neutron capture therapy. Alpha autoradiography has generally been used to detect the microdistribution of 10B in a cell. Although it has been performed using a reactor-based neutron source, the realization of an accelerator-based thermal neutron irradiation field is anticipated because of its easy installation at any location and stable operation. Therefore, we propose a method using a cyclotron-based epithermal neutron source in combination with a water phantom to produce a thermal neutron irradiation field for alpha autoradiography. This system can supply a uniform thermal neutron field with an intensity of 1.7×109 (cm−2 s−1) and an area of 40 mm in diameter. In this paper, we give an overview of our proposed system and describe a demonstration test using a mouse liver sample injected with 500 mg/kg of boronophenyl-alanine. - Highlights: • We developed a thermal neutron irradiation field using cyclotron based epithermal neutron source combination with a water phantom for alpha autoradiography. • The uniform thermal neutron irradiation field with an intensity of 1.7×109 (cm−2 s−1) with a size of 40 mm in diameter was obtained. • Demonstration test of alpha autoradiography using a liver sample with the injection of BPA was performed. • Boron image discriminated with the background event of protons was clearly shown by means of the particle identification

  7. Fast Neutron Radiography at an RFQ Accelerator System

    Science.gov (United States)

    Daniels, G. C.; Franklyn, C. B.; Dangendorf, V.; Buffler, A.; Bromberger, B.

    This work introduces the Necsa Radio Frequency Quadrupole (RFQ) accelerator facility and its work concerning fast neutron radiography (FNR). Necsa operates a 4-5 MeV, up to 50 mA deuteron RFQ. The previous deuterium gas target station has been modified to enable producing a white neutron beam employing a solid B4C target. Furthermore, the high energy beam transport (HEBT) section is under adjustment to achieve a longer flight-path and a better focus. This work presents an overview of the facility, the modifications made, and introduces past and ongoing neutron radiography investigations.

  8. Computation methods for neutron, heat and radiation damage properties of pulsed neutron sources

    International Nuclear Information System (INIS)

    The results of calculations of neutron yield, heat and nuclei-products distributions for heavy extended targets (natural W, Pb, and depleted U cylindrical targets; D=20 cm, L=60 cm) irradiated with proton beam of energy up to 100 GeV are presented as well as the radiation damage cross sections for thin layers of structure materials. The calculations were made with Monte Carlo method on the base of exclusive high energy hadron transport code SHIELD. The comparison with available experimental data is given. An expediency of elaboration of spallation neutron source based on high-energy accelerator is briefly discussed. (author) 5 figs., 17 refs

  9. Epithermal neutron tomography using compact electron linear accelerator

    International Nuclear Information System (INIS)

    Neutron resonance absorption spectroscopy (N-RAS) with a pulsed neutron source can distinguish the dynamics of individual nuclides having resonance peaks on epithermal neutron region. The analyzed internal information of nuclide presence and its effective temperature can be reconstructed as distributions over the object cross-section using computed tomography (CT). Because some of the resonance absorption cross-sections have very large values, N-RAS could match the small neutron pulsed source by its high sensitivity. In this study, we have constructed a new instrument of N-RAS on a compact electron linac neutron source. Resonance absorption measurements and CT imaging with the instrument have succeeded for some kinds of nuclide.

  10. Analysis of accelerator based neutron spectra for BNCT using proton recoil spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wielopolski, L.; Ludewig, H.; Powell, J.R.; Raparia, D.; Alessi, J.G.; Lowenstein, D.I.

    1999-03-01

    Boron Neutron Capture Therapy (BNCT) is a promising binary treatment modality for high-grade primary brain tumors (glioblastoma multiforme, GM) and other cancers. BNCT employs a boron-10 containing compound that preferentially accumulates in the cancer cells in the brain. Upon neutron capture by {sup 10}B energetic alpha particles and triton released at the absorption site kill the cancer cell. In order to gain penetration depth in the brain Fairchild proposed, for this purpose, the use of energetic epithermal neutrons at about 10 keV. Phase 1/2 clinical trials of BNCT for GM are underway at the Brookhaven Medical Research Reactor (BMRR) and at the MIT Reactor, using these nuclear reactors as the source for epithermal neutrons. In light of the limitations of new reactor installations, e.g. cost, safety and licensing, and limited capability for modulating the reactor based neutron beam energy spectra, alternative neutron sources are being contemplated for wider implementation of this modality in a hospital environment. For example, accelerator based neutron sources offer the possibility of tailoring the neutron beams, in terms of improved depth-dose distributions, to the individual and offer, with relative ease, the capability of modifying the neutron beam energy and port size. In previous work new concepts for compact accelerator/target configuration were published. In this work, using the Van de Graaff accelerator the authors have explored different materials for filtering and reflecting neutron beams produced by irradiating a thick Li target with 1.8 to 2.5 MeV proton beams. However, since the yield and the maximum neutron energy emerging from the Li-7(p,n)Be-7 reaction increase with increase in the proton beam energy, there is a need for optimization of the proton energy versus filter and shielding requirements to obtain the desired epithermal neutron beam. The MCNP-4A computer code was used for the initial design studies that were verified with benchmark

  11. ANALYSIS OF ACCELERATOR BASED NEUTRON SPECTRA FOR BNCT USING PROTON RECOIL SPECTROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    WIELOPOLSKI,L.; LUDEWIG,H.; POWELL,J.R.; RAPARIA,D.; ALESSI,J.G.; LOWENSTEIN,D.I.

    1998-11-06

    Boron Neutron Capture Therapy (BNCT) is a promising binary treatment modality for high-grade primary brain tumors (glioblastoma multiforme, GM) and other cancers. BNCT employs a boron-10 containing compound that preferentially accumulates in the cancer cells in the brain. Upon neutron capture by {sup 10}B energetic alpha particles and triton released at the absorption site kill the cancer cell. In order to gain penetration depth in the brain Fairchild proposed, for this purpose, the use of energetic epithermal neutrons at about 10 keV. Phase I/II clinical trials of BNCT for GM are underway at the Brookhaven Medical Research Reactor (BMRR) and at the MIT Reactor, using these nuclear reactors as the source for epithermal neutrons. In light of the limitations of new reactor installations, e.g. cost, safety and licensing, and limited capability for modulating the reactor based neutron beam energy spectra alternative neutron sources are being contemplated for wider implementation of this modality in a hospital environment. For example, accelerator based neutron sources offer the possibility of tailoring the neutron beams, in terms of improved depth-dose distributions, to the individual and offer, with relative ease, the capability of modifying the neutron beam energy and port size. In previous work new concepts for compact accelerator/target configuration were published. In this work, using the Van de Graaff accelerator the authors have explored different materials for filtering and reflecting neutron beams produced by irradiating a thick Li target with 1.8 to 2.5 MeV proton beams. However, since the yield and the maximum neutron energy emerging from the Li-7(p,n)Be-7 reaction increase with increase in the proton beam energy, there is a need for optimization of the proton energy versus filter and shielding requirements to obtain the desired epithermal neutron beam. The MCNP-4A computer code was used for the initial design studies that were verified with benchmark

  12. Accelerator x-ray sources

    CERN Document Server

    Talman, Richard

    2007-01-01

    This first book to cover in-depth the generation of x-rays in particle accelerators focuses on electron beams produced by means of the novel Energy Recovery Linac (ERL) technology. The resulting highly brilliant x-rays are at the centre of this monograph, which continues where other books on the market stop. Written primarily for general, high energy and radiation physicists, the systematic treatment adopted by the work makes it equally suitable as an advanced textbook for young researchers.

  13. An accelerator-based epithermal neutron beam design for BNCT and dosimetric evaluation using a voxel head phantom.

    Science.gov (United States)

    Lee, Deok-jae; Han, Chi Young; Park, Sung Ho; Kim, Jong Kyung

    2004-01-01

    The beam shaping assembly design has been investigated in order to improve the epithermal neutron beam for accelerator-based boron neutron capture therapy in intensity and quality, and dosimetric evaluation for the beams has been performed using both mathematical and voxel head phantoms with MCNP runs. The neutron source was assumed to be produced from a conventional 2.5 MeV proton accelerator with a thick (7)Li target. The results indicate that it is possible to enhance epithermal neutron flux remarkably as well as to embody a good spectrum shaping to epithermal neutrons only with the proper combination of moderator and reflector. It is also found that a larger number of thermal neutrons can reach deeply into the brain and, therefore, can reduce considerably the treatment time for brain tumours. Consequently, the epithermal neutron beams designed in this study can treat more effectively deep-seated brain tumours.

  14. Measurement of accelerator neutron radiation field spectrum by Extended Range Neutron Multisphere Spectrometers and unfolding program

    CERN Document Server

    Li, Guanjia; Ma, Zhongjian; Guo, Siming; Yan, Mingyang; Shi, Haoyu; Xu, Chao

    2015-01-01

    This paper described a measurement of accelerator neutron radiation field at a transport beam line of Beijing-TBF. The experiment place was be selected around a Faraday Cup with a graphite target impacted by electron beam at 2.5GeV. First of all, we simulated the neutron radiation experiment by FLUKA. Secondly, we chose six appropriate ERNMS according to their neutron fluence response function to measure the neutron count rate. Then the U_M_G package program was be utilized to unfolding experiment data. Finally, we drew a comparison between the unfolding with the simulation spectrum and made an analysis about the result.

  15. Neutron science opportunities at pulsed spallation neutron sources

    International Nuclear Information System (INIS)

    Using the IPNS Upgrade plan developed at Argonne National Laboratory as a worked example of the design of a pulsed spallation neutron source, this paper explores some of the scientific applications of an advanced facility for materials science studies and the instrumentation for those purposes

  16. High energy neutron source for materials research and development

    International Nuclear Information System (INIS)

    Requirements for neutron source for nuclear materials research are reviewed and ESNIT, Energy Selective Neutron Irradiation Test facility proposed by JAERI is discussed. Its principal aims of a wide neutron energy tunability and spectra peaking at each energy to enable characterization of material damage process are demanding but attractive goals which deserve detailed study. It is also to be noted that the requirements make a difference in facility design from those of FMIT, IFMIF and other high energy intense neutron sources built or planned to date. Areas of technologies to be addressed to realize the ESNIT facility are defined and discussed. In order to get neutron source having desired spectral characteristics keeping moderate intensity, projectile and target combinations must be examined including experimentation if necessary. It is also desired to minimize change of flux density and energy spectrum according to location inside irradiation chamber. Extended target or multiple targets configuration might be a solution as well as specimen rotation and choice of combination of projectile and target which has minimum velocity of the center of mass. Though relevant accelerator technology exists, it is to be stressed that considerable efforts must be paid, especially in the area of target and irradiation devices to get ESNIT goal. Design considerations to allow hands-on maintenance and future upgrading possibility are important either, in order to exploit the facility fully for nuclear materials research and development. (author)

  17. Proposed pulsed neutron source for radiotherapy and radiography

    International Nuclear Information System (INIS)

    Conventional radiation therapy involves low Linear Energy Transfer (LET) radiations like high energy electrons and photons. The basic effects of these ionizing radiations are to destroy the ability of cells to divide, by damaging their DNA strands. For low LET radiations, the damage is induced primarily by activated radicals produced from atomic interactions. Over the energy range of therapeutically used X-rays, typically 100 keV to 25 MeV, approximately the same physical dose needs to be delivered at different energies to reach a given biological endpoint, resulting in similar Relative Biological Effectiveness (RBEs). High LET radiations such as protons, neutrons, however, result in biological damage that is generally larger per unit dose than for X-rays, resulting in an elevated RBE. In case of neutrons, the recoils and nuclear disintegration product contributes to the dose are responsible for a high energy transfer to the biologically active molecules and destroy them in turn. High RBE, LET characteristics and comparatively good Dose Distribution Advantage (DDA), are the main attractive feature of the neutron therapy. As the biological effectiveness of neutrons is high, the required tumor dose is about one third the dose required with photons. Moreover, the tumor cell damaged by low LET radiation has a good chance to repair and continue to grow, while for tumors treated by neutrons the chance for repairing of tumor is very small. Therefore, the neutron therapy is presently realized in two versions: Neutron Capture Therapy (NCT) and the Fast Neutron Therapy (FNT). In NCT, the isotope with large absorption cross-section for thermal/epithermal neutrons is introduced into the body mainly through the blood, while FNT uses fast neutron with high penetrability and treats the malignant tumors of the head, neck, dairy gland, osteogeneous sarcomas, etc. Therefore, in the present paper, considering the importance of the field, the 6 MeV electron accelerator based pulsed

  18. Laser ion source for particle accelerators

    CERN Document Server

    Sherwood, T R

    1995-01-01

    There is an interest in accelerating atomic nuclei to produce particle beams for medical therapy, atomic and nuclear physics, inertial confinement fusion and particle physics. Laser Ion Sources, in which ions are extracted from plasma created when a high power density laser beam pulse strikes a solid surface in a vacuum, are not in common use. However, some new developments in which heavy ions have been accelerated show that such sources have the potential to provide the beams required for high-energy accelerator systems.

  19. Powerful pulsed neutron sources for research with a pulsed magnetic field

    International Nuclear Information System (INIS)

    The prospects for neutron investigations into the magnetic properties of condensed matter with the use of powerful pulsed neutron sources [Japan Spallation Neutron Source (JSNS) (Tokai, Japan), TIRAN (Zababakhin All-Russia Research Institute of Technical Physics, Russian Federal Nuclear Center, Snezhinsk, Russia), Large Hadron Collider (LHC) (CERN)] and pulsed magnetic fields are considered. It is demonstrated that the diffraction measurements of the magnetic states induced by a magnetic field of up to 700-1000 kOe can be performed at the TIRAN reactor and the neutron source that can be developed on the basis of the LHC accelerator.

  20. Concrete enclosure to shield a neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Villagrana M, L. E.; Rivera P, E.; De Leon M, H. A.; Soto B, T. G.; Hernandez D, V. M.; Vega C, H. R., E-mail: emmanuelvillagrana@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Apdo. Postal 336, 98000 Zacatecas (Mexico)

    2012-10-15

    In the aim to design a shielding for a {sup 239}PuBe isotopic neutron source several Monte Carlo calculations were carried out using MCNP5 code. First, a point-like source was modeled in vacuum and the neutron spectrum and the ambient dose equivalent were calculated at several distances ranging from 5 up to 150 cm, these calculations were repeated including air, and a 1 x 1 x 1 m{sup 3} enclosure that was shielded with 5, 15, 20, 25, 30, 50 and 80 cm-thick Portland type concrete walls. At all the points located inside the enclosure neutron spectra from 10{sup -8} up 0.5 MeV were the same regardless the distance from the source showing the room-return effect, for energies larger than 0.5 MeV neutron spectra are diminished as the distance increases. Outside the enclosure it was noticed that neutron spectra becomes -softer- as the concrete thickness increases due to reduction of mean neutron energy. With the ambient dose values the attenuation curve in terms of concrete thickness was calculated. (Author)

  1. 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.

  2. High-current electrostatic accelerator-tandem for the neutron therapy facility

    International Nuclear Information System (INIS)

    Original 2.5 MeV, 50 mA proton tandem accelerator for the neutron therapy facility is described. The main idea of tandem usage is providing high rate acceleration of high current hydrogen negative ions by special geometry of potential electrodes with vacuum insulation and one strongly focusing lens. Pulse 1 MeV vacuum insulation tandem accelerator experimental results are presented. Steady-state 100 kW 1.25 MV sectioned rectifier is a high voltage source. The rectifier is a part of the industrial ELV-8 electron accelerator developed at BINP and widely used. Accelerating voltage is stabilized with accuracy of 0.1 %. Various charge-exchange targets are considered. Namely, targets are gas target with outward pumping, gas target with pumping inside of high-voltage electrode, and liquid lithium stream target. Problems of development of steady-state 50 - 100 mA source of hydrogen negative ions are discussed. (author)

  3. Resolution in deep inelastic neutron scattering using pulsed neutron sources

    International Nuclear Information System (INIS)

    The principle components of the resolution function for deep inelastic neutron scattering experiments on pulsed neutron sources have been calculated directly in atomic momentum space. Analytical expressions for the relative contributions from the energy, angular and time resolutions are presented for both direct and indirect geometry spectrometers. The general trend in the behaviour of the resolution as a function of neutron energy and atomic mass is presented, and the results of numerical calculations for recoil scattering from hydrogen, helium and beryllium using the ISIS spectrometers HET and eVS, are given. It is shown that the resolution difference between HET and eVS is significantly reduced when compared in atomic momentum space rather than in energy space. Moreover, the contribution from the angular resolution term is only significant for atomic masses <4 au. (author)

  4. Inelastic neutron scattering spectrometer for the IN-06 neutron source at the Moscow meson factory

    International Nuclear Information System (INIS)

    In the spectrometers in which the so-called inverse geometry of scattering is used, the scattering neutron energy, E2, is fixed and the initial neutron energy, E1, is determined by source to sample time of flight. The inverse geometry method is a unique reliable means for determination of the absolute intensity of spectral lines. It is possible because this method allows experiments in a wide range transferred energies to be carried out without changing the experiment geometry. Such spectrometers possess a good definite dependence of the transfer energy on momentum transfer. This allows one to extract complementary to optical methods information from the experimental data. The KDSOG-M spectrometer was created at the IBR-2 pulsed reactor of JINR for investigation of the lattice dynamics of solids and simultaneous analysis of the phase structure of samples. For analysis of the scattering neutron energy polycrystal filters and single crystals are used. Creation of the IN-06 neutron source based on the proton accelerator of the Moscow meson factory leads to the necessary formation of a scientific research program for condensed matter physics. Re-equipment of the KDSOG-M spectrometer for use at the IN-06 neutron source includes preparation of an instrumental basis for carrying out experiments in solid state physics and other fields (biophysics, applied science and so on). This work is a project for transfer and updating the inverse geometry inelastic neutron scattering spectrometer KDSOG-M for use at the IN-06 neutron source of Moscow meson factory. (author) 10 figs., 4 refs

  5. Negative ion sources for tandem accelerator

    International Nuclear Information System (INIS)

    Four kinds of negative ion sources (direct extraction Duoplasmatron ion source, radial extraction Penniing ion source, lithium charge exchange ion source and Middleton-type sputter ion source) have been installed in the JAERI tandem accelerator. The ion sources can generate many negative ions ranging from Hydrogen to Uranium with the exception of Ne, Ar, Kr, Xe and Rn. Discussions presented in this report include mechanisms of negative ion formation, electron affinity and stability of negative ions, performance of the ion sources and materials used for negative ion production. Finally, the author will discuss difficult problems to be overcome in order to get any negative ion sufficiently. (author)

  6. Occupational dose due to neutrons in medical linear accelerators

    International Nuclear Information System (INIS)

    This paper describes a semi-empirical method to calculate the occupational dose due to neutrons and capture gamma rays in medical linear accelerators. It compares theoretical dose values with measurements performed in several 15 MeV medical accelerators installed in the country. Good agreement has been found between calculations made using the model and dose measurements, except for those accelerator rooms in which the maze length was shorter than the postulated tenth value distance. For those cases the model seems to overestimate neutron dose. The results demonstrate that the semi-empirical model is a good tool for quick and conservative shielding calculations for radiation protection purposes. Nevertheless, it is necessary to continue with the measurements in order to perform a more accurate validation of the model. (author)

  7. The cold neutron source in DR 3

    International Nuclear Information System (INIS)

    A description of the cold neutron source in DR 3 is given. The moderator of the cold neutron source is supercritical hydrogen at about 30degK and 15 bar abs. The necessary cooling capacity is supplied by two Philips Stirling B20 cryogenerators. The hydrogen is circulated between the cryogenerators and the in-pile moderator chamber by small fans. The safety of the facility is based on the use of triple containment preventing contact between hydrogen and air. The triple containment is achieved by enclosing the high vacuum system, surrounging the hydrogen system, in a helium blanket. The achieved spectrum of the thermal neutron flux and the gain factor are given as well as the experience from more than 5 years of operation. Finally some work on extension of the facility to operate two cold sources is reported. (author)

  8. Measuring and monitoring KIPT Neutron Source Facility Reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Yan [Argonne National Lab. (ANL), Argonne, IL (United States); Gohar, Yousry [Argonne National Lab. (ANL), Argonne, IL (United States); Zhong, Zhaopeng [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-08-01

    Argonne National Laboratory (ANL) of USA and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on developing and constructing a neutron source facility at Kharkov, Ukraine. The facility consists of an accelerator-driven subcritical system. The accelerator has a 100 kW electron beam using 100 MeV electrons. The subcritical assembly has keff less than 0.98. To ensure the safe operation of this neutron source facility, the reactivity of the subcritical core has to be accurately determined and continuously monitored. A technique which combines the area-ratio method and the flux-to-current ratio method is purposed to determine the reactivity of the KIPT subcritical assembly at various conditions. In particular, the area-ratio method can determine the absolute reactivity of the subcritical assembly in units of dollars by performing pulsed-neutron experiments. It provides reference reactivities for the flux-to-current ratio method to track and monitor the reactivity deviations from the reference state while the facility is at other operation modes. Monte Carlo simulations are performed to simulate both methods using the numerical model of the KIPT subcritical assembly. It is found that the reactivities obtained from both the area-ratio method and the flux-to-current ratio method are spatially dependent on the neutron detector locations and types. Numerical simulations also suggest optimal neutron detector locations to minimize the spatial effects in the flux-to-current ratio method. The spatial correction factors are calculated using Monte Carlo methods for both measuring methods at the selected neutron detector locations. Monte Carlo simulations are also performed to verify the accuracy of the flux-to-current ratio method in monitoring the reactivity swing during a fuel burnup cycle.

  9. Development of cold neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chang Oong; Cho, M. S.; Park, K. N. and others

    1999-05-01

    The purpose of this study is to develop the CNS facility in Hanaro to extend the scope of the neutron utilization and to carry out the works impossible by thermal neutrons. According to the project schedule, the establishment of the CNS concept and the basic design are performed in the phase 1, and the elementary technologies for basic design will be developed in the phase 2. Finally in the phase 3, the design of CNS will be completed, and the fabrication, the installation will be ended and then the development plan of spectrometers will be decided to establish the foothold to carry out the basic researches. This study is aimed to produce the design data and utilize them in the future basic and detail design, which include the estimation and the measurement of the heat load, the code development for the design of the in pile assembly and the heat removal system, the measurement of the shape of the CN hole, the performance test of thermosiphon and the concept of the general layout of the whole system etc.. (author)

  10. Development of cold neutron source

    International Nuclear Information System (INIS)

    The purpose of this study is to develop the CNS facility in Hanaro to extend the scope of the neutron utilization and to carry out the works impossible by thermal neutrons. According to the project schedule, the establishment of the CNS concept and the basic design are performed in the phase 1, and the elementary technologies for basic design will be developed in the phase 2. Finally in the phase 3, the design of CNS will be completed, and the fabrication, the installation will be ended and then the development plan of spectrometers will be decided to establish the foothold to carry out the basic researches. This study is aimed to produce the design data and utilize them in the future basic and detail design, which include the estimation and the measurement of the heat load, the code development for the design of the in pile assembly and the heat removal system, the measurement of the shape of the CN hole, the performance test of thermosiphon and the concept of the general layout of the whole system etc.. (author)

  11. Neutron source strength monitors for ITER

    International Nuclear Information System (INIS)

    There are several goals for the neutron source strength monitor system for the International Thermonuclear Experimental Reactor (ITER). Desired is a stable, reliable, time-dependent neutron detection system which exhibits a wide dynamic range and broad energy response to incident neutrons while being insensitive to gamma rays and having low noise characteristics in a harsh reactor environment. This system should be able to absolutely calibrated in-situ using various neutron sources. An array of proportional counters of varying sensitivities is proposed along with the most promising possible locations. One proposed location is in the pre-shields of the neutron camera collimators which would allow an integrated design of neutron systems with good detector access. As part of an ongoing conceptual design for this system, the detector-specific issues of dynamic range, performance monitoring, and sensitivity will be presented. The location options of the array will be discussed and most importantly, the calibration issues associated with a heavily shielded vessel will be presented

  12. Neutron source strength monitors for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, C.W. [Sandia National Labs., Albuquerque, NM (United States); Roquemore, A.L. [Princeton Univ., NJ (United States). Plasma Physics Lab.

    1996-05-07

    There are several goals for the neutron source strength monitor system for the International Thermonuclear Experimental Reactor (ITER). Desired is a stable, reliable, time-dependent neutron detection system which exhibits a wide dynamic range and broad energy response to incident neutrons while being insensitive to gamma rays and having low noise characteristics in a harsh reactor environment. This system should be able to absolutely calibrated in-situ using various neutron sources. An array of proportional counters of varying sensitivities is proposed along with the most promising possible locations. One proposed location is in the pre-shields of the neutron camera collimators which would allow an integrated design of neutron systems with good detector access. As part of an ongoing conceptual design for this system, the detector-specific issues of dynamic range, performance monitoring, and sensitivity will be presented. The location options of the array will be discussed and most importantly, the calibration issues associated with a heavily shielded vessel will be presented.

  13. Successful Application of Neutron Bubble Detectors in Neutron Dose Monitoring for Primus-M Election Linear Accelerators

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Neutrons produced by 10 MeV medical electronic linear accelerators used for radiotherapy treatments may be harmful for medical personnel and patients. These neutrons are generated by the photon-induced

  14. Development of nuclear design criteria for neutron spallation sources

    Energy Technology Data Exchange (ETDEWEB)

    Sordo, F.; Abanades, A. [E.T.S. Industriales, Madrid Polytechnic University, UPM, J.Gutierrez Abascal, 2 -28006 Madrid (Spain)

    2008-07-01

    Spallation neutron sources allow obtaining high neutronic flux for many scientific and industrial applications. In recent years, several proposals have been made about its use, notably the European Spallation Source (ESS), the Japanese Spallation Source (JSNS) and the projects of Accelerator-Driven Subcritical reactors (ADS), particularly in the framework of EURATOM programs. Given their interest, it seems necessary to establish adequate design basis for guiding the engineering analysis and construction projects of this kind of installations. In this sense, all works done so far seek to obtain particular solutions to a particular design, but there has not been any general development to set up an engineering methodology in this field. In the integral design of a spallation source, all relevant physical processes that may influence its behaviour must be taken into account. Neutronic aspects (emitted neutrons and their spectrum, generation performance..), thermomechanical (energy deposition, cooling conditions, stress distribution..), radiological (spallation waste activity, activation reactions and residual heat) and material properties alteration due to irradiation (atomic displacements and gas generation) must all be considered. After analysing in a systematic manner the different options available in scientific literature, the main objective of this thesis was established as making a significant contribution to determine the limiting factors of the main aspects of spallation sources, its application range and the criteria for choosing optimal materials. To achieve this goal, a series of general simulations have been completed, covering all the relevant physical processes in the neutronic and thermal-mechanical field. Finally, the obtained criteria have been applied to the particular case of the design of the spallation source of subcritical reactors PDX-ADS and XT-ADS. These two designs, developed under the European R and D Framework Program, represent nowadays

  15. Options for a next generation neutron source for neutron scattering based on the projected linac facility at JAERI

    International Nuclear Information System (INIS)

    Japan Atomic Energy Research Institute (JAERI) has a project to construct a high intensity proton accelerator to promote wide basic science using neutrons and nuclear power technologies such as radioactive nuclide transmutation. One of the most important field for utilization of neutron beam is neutron scattering. The energy and the averaged current obtained by the proton accelerator are 1.5 GeV and 4-5.3 mA, respectively and these provide 6-8 MW power. The repetition frequency is 50-60 Hz. Evaluation of options for the use of accelerators for neutron production for neutron scattering research and investigation of the neutron research opportunities offered by sharing the superconducting linac planned at JAERI were discussed. There are two ways of the utilization of proton beams for neutron scattering experiment. One is for long pulse spallation source (LPSS) and the other is for short pulse spallation source (SPSS). Quantitative evaluation of instrument performance with LPSS and SPSS was examined in the intensive discussion, calculations, workshop on this topics with Prof. F. Mezei who stayed at JAERI from October 24 to November 6, 1996. A report of the collaborative workshop will be also published separately. (author)

  16. High-power liquid-lithium target prototype for accelerator-based boron neutron capture therapy.

    Science.gov (United States)

    Halfon, S; Paul, M; Arenshtam, A; Berkovits, D; Bisyakoev, M; Eliyahu, I; Feinberg, G; Hazenshprung, N; Kijel, D; Nagler, A; Silverman, I

    2011-12-01

    A prototype of a compact Liquid-Lithium Target (LiLiT), which will possibly constitute an accelerator-based intense neutron source for Boron Neutron Capture Therapy (BNCT) in hospitals, was built. The LiLiT setup is presently being commissioned at Soreq Nuclear Research Center (SNRC). The liquid-lithium target will produce neutrons through the (7)Li(p,n)(7)Be reaction and it will overcome the major problem of removing the thermal power generated using a high-intensity proton beam (>10 kW), necessary for sufficient neutron flux. In off-line circulation tests, the liquid-lithium loop generated a stable lithium jet at high velocity, on a concave supporting wall; the concept will first be tested using a high-power electron beam impinging on the lithium jet. High intensity proton beam irradiation (1.91-2.5 MeV, 2-4 mA) will take place at Soreq Applied Research Accelerator Facility (SARAF) superconducting linear accelerator currently in construction at SNRC. Radiological risks due to the (7)Be produced in the reaction were studied and will be handled through a proper design, including a cold trap and appropriate shielding. A moderator/reflector assembly is planned according to a Monte Carlo simulation, to create a neutron spectrum and intensity maximally effective to the treatment and to reduce prompt gamma radiation dose risks.

  17. Options for neutron scattering instruments on long pulse neutron sources

    International Nuclear Information System (INIS)

    Instrumenttion on long pulse sources can be approached either by instruments from short pulse sources and hence using mainly inverted time of flight techniques or by adopting reactor type instruments and making use of the time dependence of the source flux to enhance their performance substantially. While the first approach requires more or less single use of a beam line by one instrument, the second one allows multiple use of neutron guides, as customary on reactors and hence can make much better use of the source with gains up to 100 for time of flight spectrometers. To a certain extent, the design parameters of the source depend on which of the two approaches is chosen. (author) 8 figs., 1 tab., 16 refs

  18. Neutron gamma fraction imaging: Detection, location and identification of neutron sources

    International Nuclear Information System (INIS)

    In this paper imaging of neutron sources and identification and separation of a neutron source from another neutron source is described. The system is based upon organic liquid scintillator detector, tungsten collimator, bespoke fast digitiser and adjustable equatorial mount. Three environments have been investigated with this setup corresponding to an AmBe neutron source, a 252Cf neutron source and both sources together separated in space. In each case, events are detected, digitised, discriminated and radiation images plotted corresponding to the area investigated. The visualised neutron count distributions clearly locate the neutron source and, relative gamma to neutron (or neutron to gamma) fraction images aid in discriminating AmBe sources from 252Cf source. The measurements were performed in the low scatter facility of the National Physical Laboratory, Teddington, UK

  19. The concept of a European spallation neutron source (ESS)

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, G.S. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-11-01

    The next generation neutron source in Europe, which was studied by a collaboration between twelve laboratories, has been conceived as a 5 MW short pulse spallation source because of the superior overall scientific potential attributed to such a facility relative to all other options considered. While the accelerator side can use essentially established technology with some extensions in performance, a novel target concept based on the use of Mercury as a flowing liquid metal target was developed, which is not only expected to lead the way further into the future, but which was also found to give the best neutronic performance of all known choices. Close permanent interaction with a large user community yielded important input for the concept in general and for the upcoming R and D and design phases in particular. (author)

  20. Spallation neutron source RF cavity bias system

    International Nuclear Information System (INIS)

    The Spallation Neutron Source r.f. cavity bias system is described under the topic headings: bias system, r.f. cavity, cables, d.c. bias power supply, transistor regulator and control system. Calculation of 4 core 300 mm solid aluminium cable inductance, coaxial shunt frequency response and transistor regulator computed frequency response, are discussed in appendices 1-3. (U.K.)

  1. Negative hydrogen ion sources for accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Moehs, D.P.; /Fermilab; Peters, J.; /DESY; Sherman, J.; /Los Alamos

    2005-08-01

    A variety of H{sup -} ion sources are in use at accelerator laboratories around the world. A list of these ion sources includes surface plasma sources with magnetron, Penning and surface converter geometries as well as magnetic-multipole volume sources with and without cesium. Just as varied is the means of igniting and maintaining magnetically confined plasmas. Hot and cold cathodes, radio frequency, and microwave power are all in use, as well as electron tandem source ignition. The extraction systems of accelerator H{sup -} ion sources are highly specialized utilizing magnetic and electric fields in their low energy beam transport systems to produce direct current, as well as pulsed and/or chopped beams with a variety of time structures. Within this paper, specific ion sources utilized at accelerator laboratories shall be reviewed along with the physics of surface and volume H{sup -} production in regard to source emittance. Current research trends including aperture modeling, thermal modeling, surface conditioning, and laser diagnostics will also be discussed.

  2. MALT accelerator facility; characteristic of ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Nakano, Chuichiro; Kobayashi, Koichi; Matsuzaki, Hiroyuki; Sunohara, Yoko [Tokyo Univ. (Japan)

    2001-02-01

    A tandem accelerator has been operated since 1995 with a continual effort to increase the accuracy and reliability of the measurement. In the present paper, after a brief discussion on a cesium sputter ion source incorporated in the MALT accelerator, basic characteristics such as temperature of cesium reservoir, and ioniser plate cathode potential. Production of negative ions in the ion source proceed in two step. The first step is generation of positive ions due to the surface ionization on a hot Ta plate, and the second step, electron detachment on a cathode. (M. Tanaka)

  3. Evaluation of the photo-neutron source and delayed neutrons in the Syrian miniature neutron source reactor

    International Nuclear Information System (INIS)

    A mathematical model has been developed to simulate the dynamic behavior of the Syrian Miniature Neutron Source Reactor (MNSR). The model is used to assess and evaluate the core average temperature as a function of the overall reactivity load in the core on one hand. On the other hand, the model is utilized to evaluate dynamically the photo and delayed neutron effects in MNSR. The model considers relevant physical phenomena that govern the core such as reactor kinetics, reactivity feedbacks due to coolant temperature and xenon, and thermalhydraulics. Natural convection and point kinetics including the prompt jump and complete mixing approximations were employed. Peak power, reactivity core load, core outlet temperature, and other variables are predicted during self-limiting power excursions. Direct photo-neutron sources strength was dynamically evaluated for the MNSR in subcritical condition. Two different static methods were applied for comparison. In addition, measurement of the photo-neutron source was made using neutron flux monitors and neutron activation analysis technique. Results for both methods were in good agreement. Dynamics effect of the photo neutron source on reactor response to reactivity insertions was demonstrated. Photo-neutron source existence due to beryllium reflector was realized. Compared to related references, close results have been obtained. Core average temperature was studied as a function of reactivity during reactor operation and transients. An overall rough estimate of core average temperature as a function of reactivity load is presented; hence, a procedure to measure such temperature is suggested. (author)

  4. Cold moderators for pulsed neutron sources

    International Nuclear Information System (INIS)

    This paper reviews cold moderators in pulsed neutron sources and provides details of the performance of different cold moderator materials and configurations. Analytical forms are presented which describe wavelength spectra and emission time distributions. Several types of cooling arrangements used in pulsed source moderators are described. Choices of materials are surveyed. The author examines some of the radiation damage effects in cold moderators, including the phenomenon of ''burping'' in irradiated cold solid methane. 9 refs., 15 figs., 4 tabs

  5. Comparison of depth-dose distributions between reactor and accelerator neutron beams proposed by design studies

    International Nuclear Information System (INIS)

    Accelerator epithermal neutron beams produced by 7Li(p,n)7Be reactions were compared with reactor neutron beams using a fission converter (20% enriched 235U 5mm-thick plate) from view points of neutron spectrum and depth-dose distributions in a phantom. It is possible to design accelerator epithermal neutron beams having better depth-dose distributions than reactor neutron beams. (author)

  6. 5 MW pulsed spallation neutron source, Preconceptual design study

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    This report describes a self-consistent base line design for a 5 MW Pulsed Spallation Neutron Source (PSNS). It is intended to establish feasibility of design and as a basis for further expanded and detailed studies. It may also serve as a basis for establishing project cost (30% accuracy) in order to intercompare competing designs for a PSNS not only on the basis of technical feasibility and technical merit but also on the basis of projected total cost. The accelerator design considered here is based on the objective of a pulsed neutron source obtained by means of a pulsed proton beam with average beam power of 5 MW, in {approx} 1 {mu}sec pulses, operating at a repetition rate of 60 Hz. Two target stations are incorporated in the basic facility: one for operation at 10 Hz for long-wavelength instruments, and one operating at 50 Hz for instruments utilizing thermal neutrons. The design approach for the proton accelerator is to use a low energy linear accelerator (at 0.6 GeV), operating at 60 Hz, in tandem with two fast cycling booster synchrotrons (at 3.6 GeV), operating at 30 Hz. It is assumed here that considerations of cost and overall system reliability may favor the present design approach over the alternative approach pursued elsewhere, whereby use is made of a high energy linear accelerator in conjunction with a dc accumulation ring. With the knowledge that this alternative design is under active development, it was deliberately decided to favor here the low energy linac-fast cycling booster approach. Clearly, the present design, as developed here, must be carried to the full conceptual design stage in order to facilitate a meaningful technology and cost comparison with alternative designs.

  7. Sources of radiation from neutron stars

    CERN Document Server

    Schutz, B F

    1998-01-01

    I give a brief introduction to the problem of detecting gravitational radiation from neutron stars. After a review of the mechanisms by which such stars may produce radiation, I consider the different search strategies appropriate to the different kinds of sources: isolated known pulsars, neutron stars in binaries, and unseen neutron stars. The problem of an all-sky survey for unseen stars is the most taxing one that we face in analysing data from interferometers. I describe the kinds of hierarchical methods that are now being investigated to reach the maximal sensitivity, and I suggest a replacement for standard Fourier-transform search methods that requires fewer floating-point operations for Fourier-based searches over large parameter spaces, and in addition is highly parallelizable, working just as well on a loosely coupled network of workstations as on a tightly coupled parallel computer.

  8. Design of a High Intensity Neutron Source for Neutron-Induced Fission Yield Studies

    CERN Document Server

    Lantz, M; Jokinen, A; Kolhinen, V S; Mattera, A; Penttilä, H; Pomp, S; Rakopoulos, V; Rinta-Antila, S; Solders, A

    2013-01-01

    The upgraded IGISOL facility with JYFLTRAP, at the accelerator laboratory of the University of Jyv\\"askyl\\"a, has been supplied with a new cyclotron which will provide protons of the order of 100 {\\mu}A with up to 30 MeV energy, or deuterons with half the energy and intensity. This makes it an ideal place for measurements of neutron-induced fission products from various actinides, in view of proposed future nuclear fuel cycles. The groups at Uppsala University and University of Jyv\\"askyl\\"a are working on the design of a neutron converter that will be used as neutron source in fission yield studies. The design is based on simulations with Monte Carlo codes and a benchmark measurement that was recently performed at The Svedberg Laboratory in Uppsala. In order to obtain a competitive count rate the fission targets will be placed very close to the neutron converter. The goal is to have a flexible design that will enable the use of neutron fields with different energy distributions. In the present paper, some co...

  9. Determination of neutron generation time in miniature neutron source reactor by measurement of neutronics transfer function

    Energy Technology Data Exchange (ETDEWEB)

    Hainoun, A.; Khamis, I. [Atomic Energy Commission, Damascus (Syria). Dept. of Physics

    2000-02-01

    The prompt neutron generation time {lambda} and the total effective fraction of delayed neutrons (including the effect of photoneutrons) {beta} have been experimentally determined for the miniature neutron source reactor (MNSR) of Syria. The neutron generation time was found by taking measurements of the reactor open-loop transfer function using newly devised reactivity-step-ejection method by the reactor pneumatic rabbit system. Small reactivity perturbations i.e. step changes of reactivity starting from steady state, were introduced into the reactor during operation at low power level i.e. zero-power. Relative neutron flux and reactivity versus time were obtained. Using transfer function analysis as well as least square fitting techniques and measuring the delayed neutrons fraction, the neutron generation time was determined to be 74.6{+-}1.57 {mu}s. Using the prompt jump approximation of neutron flux, the total effective fraction of delayed neutrons was measured and found to be 0.00783{+-}0.00017. Measured values of {lambda} and {beta} were found to be very consistent with calculated ones reported in the safety analysis report. (orig.)

  10. Determination of neutron generation time in miniature neutron source reactor by measurement of neutronics transfer function

    International Nuclear Information System (INIS)

    The prompt neutron generation time Λ and the total effective fraction of delayed neutrons (including the effect of photoneutrons) β have been experimentally determined for the miniature neutron source reactor (MNSR) of Syria. The neutron generation time was found by taking measurements of the reactor open-loop transfer function using newly devised reactivity-step-ejection method by the reactor pneumatic rabbit system. Small reactivity perturbations i.e. step changes of reactivity starting from steady state, were introduced into the reactor during operation at low power level i.e. zero-power. Relative neutron flux and reactivity versus time were obtained. Using transfer function analysis as well as least square fitting techniques and measuring the delayed neutrons fraction, the neutron generation time was determined to be 74.6±1.57 μs. Using the prompt jump approximation of neutron flux, the total effective fraction of delayed neutrons was measured and found to be 0.00783±0.00017. Measured values of Λ and β were found to be very consistent with calculated ones reported in the safety analysis report. (orig.)

  11. Plant model of KIPT neutron source facility simulator

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Yan [Argonne National Lab. (ANL), Argonne, IL (United States); Wei, Thomas Y. [Argonne National Lab. (ANL), Argonne, IL (United States); Grelle, Austin L. [Argonne National Lab. (ANL), Argonne, IL (United States); Gohar, Yousry [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-02-01

    Argonne National Laboratory (ANL) of the United States and Kharkov Institute of Physics and Technology (KIPT) of Ukraine are collaborating on constructing a neutron source facility at KIPT, Kharkov, Ukraine. The facility has 100-kW electron beam driving a subcritical assembly (SCA). The electron beam interacts with a natural uranium target or a tungsten target to generate neutrons, and deposits its power in the target zone. The total fission power generated in SCA is about 300 kW. Two primary cooling loops are designed to remove 100-kW and 300-kW from the target zone and the SCA, respectively. A secondary cooling system is coupled with the primary cooling system to dispose of the generated heat outside the facility buildings to the atmosphere. In addition, the electron accelerator has a low efficiency for generating the electron beam, which uses another secondary cooling loop to remove the generated heat from the accelerator primary cooling loop. One of the main functions the KIPT neutron source facility is to train young nuclear specialists; therefore, ANL has developed the KIPT Neutron Source Facility Simulator for this function. In this simulator, a Plant Control System and a Plant Protection System were developed to perform proper control and to provide automatic protection against unsafe and improper operation of the facility during the steady-state and the transient states using a facility plant model. This report focuses on describing the physics of the plant model and provides several test cases to demonstrate its capabilities. The plant facility model uses the PYTHON script language. It is consistent with the computer language of the plant control system. It is easy to integrate with the simulator without an additional interface, and it is able to simulate the transients of the cooling systems with system control variables changing on real-time.

  12. Accelerator-driven X-ray Sources

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Dinh Cong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-09

    After an introduction which mentions x-ray tubes and storage rings and gives a brief review of special relativity, the subject is treated under the following topics and subtopics: synchrotron radiation (bending magnet radiation, wiggler radiation, undulator radiation, brightness and brilliance definition, synchrotron radiation facilities), x-ray free-electron lasers (linac-driven X-ray FEL, FEL interactions, self-amplified spontaneous emission (SASE), SASE self-seeding, fourth-generation light source facilities), and other X-ray sources (energy recovery linacs, Inverse Compton scattering, laser wakefield accelerator driven X-ray sources. In summary, accelerator-based light sources cover the entire electromagnetic spectrum. Synchrotron radiation (bending magnet, wiggler and undulator radiation) has unique properties that can be tailored to the users’ needs: bending magnet and wiggler radiation is broadband, undulator radiation has narrow spectral lines. X-ray FELs are the brightest coherent X-ray sources with high photon flux, femtosecond pulses, full transverse coherence, partial temporal coherence (SASE), and narrow spectral lines with seeding techniques. New developments in electron accelerators and radiation production can potentially lead to more compact sources of coherent X-rays.

  13. Calculation of the neutron importance and weighted neutron generation time using MCNIC method in accelerator driven subcritical reactors

    International Nuclear Information System (INIS)

    Highlights: • All reactor kinetic parameters are importance weighted quantities. • MCNIC method has been developed for calculating neutron importance in ADSRs. • Mean generation time has been calculated in spallation driven systems. -- Abstract: The difference between non-weighted neutron generation time (Λ) and the weighted one (Λ†) can be quite significant depending on the type of the system. In the present work, we will focus on developing MCNIC method for calculation of the neutron importance (Φ†) and importance weighted neutron generation time (Λ†) in accelerator driven systems (ADS). Two hypothetic bare and graphite reflected spallation source driven system have been considered as illustrative examples for this means. The results of this method have been compared with those obtained by MCNPX code. According to the results, the relative difference between Λ and Λ† is within 36% and 24,840% in bare and reflected illustrative examples respectively. The difference is quite significant in reflected systems and increases with reflector thickness. In Conclusion, this method may be used for better estimation of kinetic parameters rather than the MCNPX code because of using neutron importance function

  14. Beginnings of remote handling at the RAL Spallation Neutron Source

    International Nuclear Information System (INIS)

    Expenditure of funds and resources for remote maintenance systems traditionally are delayed until late in an accelerator's development. However, simple remote-surveillance equipment can be included early in facility planning to set the stage for future remote-handling needs and to identify appropriate personnel. Some basic equipment developed in the UK at the Spallation Neutron Source (SNS) that serves this function and that has been used to monitor beam loss during commissioning is described. A photograph of this equipment, positioned over the extractor septum magnet, is shown. This method can serve as a pattern approach to the problem of initiating remote-handling activities in other facilities

  15. Measurements of prompt gamma-rays from fast-neutron induced fission with the LICORNE directional neutron source

    CERN Document Server

    Wilson, J N; Halipre, P; Oberstedt, S; Oberstedt, A

    2014-01-01

    At the IPN Orsay we have developed a unique, directional, fast neutron source called LICORNE, intended initially to facilitate prompt fission gamma measurements. The ability of the IPN Orsay tandem accelerator to produce intense beams of $^7$Li is exploited to produce quasi-monoenergetic neutrons between 0.5 - 4 MeV using the p($^7$Li,$^7$Be)n inverse reaction. The available fluxes of up to 7 × 10$^7$ neutrons/second/steradian for the thickest hydrogen-rich targets are comparable to similar installations, but with two added advantages: (i) The kinematic focusing produces a natural neutron beam collimation which allows placement of gamma detectors adjacent to the irradiated sample unimpeded by source neutrons. (ii) The background of scattered neutrons in the experimental hall is drastically reduced. The dedicated neutron converter was commissioned in June 2013. Some preliminary results from the first experiment using the LICORNE neutron source at the IPN Orsay are presented. Prompt fission gamma rays from fas...

  16. Neutron Flux and Activation Calculations for a High Current Deuteron Accelerator

    CERN Document Server

    Coniglio, Angela; Sandri, Sandro

    2005-01-01

    Neutron analysis of the first Neutral Beam (NB) for the International Thermonuclear Experimental Reactor (ITER) was performed to provide the basis for the study of the following main aspects: personnel safety during normal operation and maintenance, radiation shielding design, transportability of the NB components in the European countries. The first ITER NB is a medium energy light particle accelerator. In the scenario considered for the calculation the accelerated particles are negative deuterium ions with maximum energy of 1 MeV. The average beam current is 13.3 A. To assess neutron transport in the ITER NB structure a mathematical model of the components geometry was implemented into MCNP computer code (MCNP version 4c2. "Monte Carlo N-Particle Transport Code System." RSICC Computer Code Collection. June 2001). The neutron source definition was outlined considering both D-D and D-T neutron production. FISPACT code (R.A. Forrest, FISPACT-2003. EURATOM/UKAEA Fusion, December 2002) was used to assess neutron...

  17. Spallation neutron source and other high intensity froton sources

    Energy Technology Data Exchange (ETDEWEB)

    Weiren Chou

    2003-02-06

    This lecture is an introduction to the design of a spallation neutron source and other high intensity proton sources. It discusses two different approaches: linac-based and synchrotron-based. The requirements and design concepts of each approach are presented. The advantages and disadvantages are compared. A brief review of existing machines and those under construction and proposed is also given. An R&D program is included in an appendix.

  18. INJECTION CHOICE FOR SPALLATION NEUTRON SOURCE RING.

    Energy Technology Data Exchange (ETDEWEB)

    WEI,J.; BEEBE-WANG,J.; BLASKIEWICZ,M.; BRODOWSKI,J.; FEDOTOV,A.; GARDNER,C.; LEE,Y.Y.; RAPARIA,D.; DANILOV,V.; HOLMES,J.; PRIOR,C.; REES,G.; MACHIDA,S.

    2001-06-18

    Injection is key in the low-loss design of high-intensity proton facilities like the Spallation Neutron Source (SNS). During the design of both the accumulator and the rapid-cycling-synchrotron version of the SNS, extensive comparison has been made to select injection scenarios that satisfy SNS's low-loss design criteria. This paper presents issues and considerations pertaining to the final choice of the SNS injection systems.

  19. Low dimensional neutron moderators for enhanced source brightness

    DEFF Research Database (Denmark)

    Mezei, Ferenc; Zanini, Luca; Takibayev, Alan;

    2014-01-01

    for cold neutrons. This model leads to the conclusions that the optimal shape for high brightness para-hydrogen neutron moderators is the quasi 1-dimensional tube and these low dimensional moderators can also deliver much enhanced cold neutron brightness in fission reactor neutron sources, compared...

  20. Technical design report of spallation neutron source facility in J-PARC

    International Nuclear Information System (INIS)

    One of the experimental facilities in Japan Proton Accelerator Research Complex (J-PARC) is the Materials and Life Science Experimental Facility (MLF), where high-intensity neutron beams are used as powerful probes for basic research on materials and life science, as well as research and development in industrial engineering. Neutrons are generated with nuclear spallation reaction by bombarding a mercury target with high-intensity proton beams. The neutrons are slowed down with supercritical hydrogen moderators and then extracted as beams to each experimental apparatus. The principal design of the spallation neutron source is compiled in this comprehensive report. (author)

  1. The spallation neutron source: New opportunities

    Indian Academy of Sciences (India)

    Ian S Anderson

    2008-11-01

    The spallation neutron source (SNS) facility became operational in the spring of 2006, and is now well on its way to become the world-leading facility for neutron scattering. Furthermore, the SNS and the HFIR reactor facility, newly outfitted with a brilliant cold source and guide hall, were brought together within a single Neutron Sciences Directorate at ORNL providing the opportunity to develop science and instrumentation programs which take advantage of the unique characteristics of each source. SNS and HFIR will both operate as scientific user facilities. Access to these facilities is being managed under an integrated proposal system, which also includes the Center for Nanophase Materials Sciences (CNMS) and the electron microscopes in the Shared Research Equipment (SHARE) program. Presently, SNS has three instruments operating in the user program and seven more will begin operations in 2008. When complete, the facility will accommodate 25 instruments enabling researchers from the United States and abroad to study materials science that forms the basis for new technologies in telecommunications, manufacturing, transportation, information technology, biotechnology, and health.

  2. Neutron sources and its dosimetric characteristics

    International Nuclear Information System (INIS)

    By means of Monte Carlo methods the spectra of the produced neutrons 252 Cf, 252 Cf/D2O, 241 Am Be, 239 Pu Be, 140 La Be, 239 Pu18O2 and 226 Ra Be have been calculated. With the information of the spectrum it was calculated the average energy of the neutrons of each source. By means of the fluence coefficients to dose it was determined, for each one of the studied sources, the fluence factors to dose. The calculated doses were H, H*(10), Hp,sIab (10, 00), EAP and EISO. During the phase of the calculations the sources were modeled as punctual and their characteristics were determined to 100 cm in the hole. Also, for the case of the sources of 239 Pu Be and 241 Am Be, were carried out calculations modeling the sources with their respective characteristics and the dosimetric properties were determined in a space full with air. The results of this last phase of the calculations were compared with the experimental results obtained for both sources. (Author)

  3. Simulation of neutron generation in short pulsed X-band linac neutron source

    International Nuclear Information System (INIS)

    It is important to improve the accuracy of nuclear cross section for waste reprocessing and design of new reactors, but facilities where nuclear fuel materials can be measured are limited. So, in Tokyo University, there is a plan of development of electron linac neutron source for analyzing nuclear data. The research reactor “Yayoi” was decommissioned in Tokyo University and by introducing this linac in the core of the reactor, measurement of nuclear fuel materials can be expected. 30 MeV X-band linac is used so this system will be compact and this enables us to introduce the system into the core of “Yayoi.” Pulse width is short in order to measure high energy neutron with TOF method. In this research, generation of electrons, acceleration and interaction with several kinds of target and moderator are simulated. (author)

  4. An outline of the proton accelerator for the neutron science project

    Energy Technology Data Exchange (ETDEWEB)

    Mizumoto, Motoharu; Kusano, Joichi; Hasegawa, Kazuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

    1997-11-01

    A research project has been proposed in JAERI aiming at exploring new basic researches and nuclear energy engineering based on a high intensity proton linac with a 1.5 GeV and 8 MW beam. The research complex will be composed of facilities such as the Neutron Scattering Facility for condensed matter physics and the Nuclear Energy Related Facility for engineering test of nuclear waste transmutation. The R and D has been carried out for the components of the low energy part of the accelerator; ion source, RFQ, DTL and RF source. For the high energy portion above 100 MeV, the development on a superconducting accelerating cavity as a major option has been performed. The paper will present the summary on a development plan to build the accelerator and the results of conceptual design study and the R and D work. (author)

  5. Advanced Neutron Source: Plant Design Requirements

    Energy Technology Data Exchange (ETDEWEB)

    1990-07-01

    The Advanced Neutron Source will be a new world-class facility for research using hot, thermal, cold, and ultra-cold neutrons. The heart of the facility will be a 330-MW (fission), heavy-water cooled and heavy-water moderated reactor. The reactor will be housed in a central reactor building, with supporting equipment located in an adjoining reactor support building. An array of cold neutron guides will fan out into a large guide hall, housing about 30 neutron research stations. Appropriate office, laboratory, and shop facilities will be included to provide a complete facility for users. The ANS is scheduled to begin operation at the Oak Ridge National Laboratory early in the next decade. This PDR document defines the plant-level requirements for the design, construction, and operation of ANS. It also defines and provides input to the individual System Design Description (SDD) documents. Together, this PDR document and the set of SDD documents will define and control the baseline configuration of ANS.

  6. Advanced Neutron Source: Plant Design Requirements

    International Nuclear Information System (INIS)

    The Advanced Neutron Source will be a new world-class facility for research using hot, thermal, cold, and ultra-cold neutrons. The heart of the facility will be a 330-MW (fission), heavy-water cooled and heavy-water moderated reactor. The reactor will be housed in a central reactor building, with supporting equipment located in an adjoining reactor support building. An array of cold neutron guides will fan out into a large guide hall, housing about 30 neutron research stations. Appropriate office, laboratory, and shop facilities will be included to provide a complete facility for users. The ANS is scheduled to begin operation at the Oak Ridge National Laboratory early in the next decade. This PDR document defines the plant-level requirements for the design, construction, and operation of ANS. It also defines and provides input to the individual System Design Description (SDD) documents. Together, this PDR document and the set of SDD documents will define and control the baseline configuration of ANS

  7. Target technology of high energy neutron source

    International Nuclear Information System (INIS)

    As a facility of high energy neutron source for materials research and development, Fusion Materials Irradiation Test Facility (FMIT) is a strong candidate. The FMIT is designed to study the irradiation effect of fusion neutron on a fusion reactor materials. The FMIT generates a high-flux, high-energy neutron, which is produced in a stripping reaction by impinging a 3.5 MeV-0.1A beam of deuterons on a flowing lithium target. Target technology obtained in the FMIT will be useful for Energy Selective Neutron Irradiation Test Facility (ESNIT) and IFMIF of D-Li stripping reaction facility. In the first report (I), the flowing lithium target of the FMIT was reviewed, and some technical considerations in design were pointed out. In the second report (II), the target assembly and target material were proposed as the option of the HEDEL reference design of FMIT in order to improve the hazard and economy for the Li system: Firstly, the exchangeable target back wall and the measures to minimize the outside device damage in case of back wall breaking, and secondly, the option of molten fluoride salt as target material were proposed. (M.T.)

  8. Accelerated oxygen precipitation in fast neutron irradiated Czochralski silicon

    Institute of Scientific and Technical Information of China (English)

    Ma Qiao-Yun; Li Yang-Xian; Chen Gui-Feng; Yang Shuai; Liu Li-Li; Niu Ping-Juan; Chen Dong-Feng; Li Hong-Tao

    2005-01-01

    Annealing effect of the oxygen precipitation and the induced defects have been investigated on the fast neutron irradiated Czochralski silicon (CZ-Si) by infrared absorption spectrum and the optical microscopy. It is found that the fast neutron irradiation greatly accelerates the oxygen precipitation that leads to a sharp decrease of the interstitial oxygen with the annealing time. At room temperature (RT), the 1107cm-1 infrared absorption band of interstitial oxygen becomes weak and broadens to low energy side. At low temperature, the infrared absorption peaks appear at 1078cm-1, 1096cm-1, and 1182cm-1, related to different shapes of the oxygen precipitates. The bulk microdefects,including stacking faults, dislocations and dislocation loops, were observed by the optical microscopy. New or large stacking faults grow up when the silicon self-interstitial atoms are created and aggregate with oxygen precipitation.

  9. CAS Accelerator Physics (Ion Sources) in Slovakia

    CERN Multimedia

    CAS School

    2012-01-01

    The CERN Accelerator School (CAS) and the Slovak University of Technology jointly organised a specialised course on ion sources, held at the Hotel Senec, Senec, Slovakia, from 29 May to 8 June, 2012.   Following some background lectures on accelerator physics and the fundamental processes of atomic and plasma physics, the course covered a wide range of topics related to ion sources and highlighted the latest developments in the field. Realistic case studies and topical seminars completed the programme. The school was very successful, with 69 participants representing 25 nationalities. Feedback from the participants was extremely positive, reflecting the high standard of the lectures. The case studies were performed with great enthusiasm and produced some excellent results. In addition to the academic programme, the participants were able to take part in a one-day excursion consisting of a guided tour of Bratislava and free time. A welcome event was held at the Hotel Senec, with s...

  10. Analysis of fuel management in the KIPT neutron source facility

    Energy Technology Data Exchange (ETDEWEB)

    Zhong Zhaopeng, E-mail: zzhong@anl.gov [Nuclear Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Gohar, Yousry; Talamo, Alberto [Nuclear Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

    2011-05-15

    Research highlights: > Fuel management of KIPT ADS was analyzed. > Core arrangement was shuffled in stage wise. > New fuel assemblies was added into core periodically. > Beryllium reflector could also be utilized to increase the fuel life. - Abstract: Argonne National Laboratory (ANL) of USA and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on the conceptual design development of an experimental neutron source facility consisting of an electron accelerator driven sub-critical assembly. The neutron source driving the sub-critical assembly is generated from the interaction of 100 KW electron beam with a natural uranium target. The sub-critical assembly surrounding the target is fueled with low enriched WWR-M2 type hexagonal fuel assemblies. The U-235 enrichment of the fuel material is <20%. The facility will be utilized for basic and applied research, producing medical isotopes, and training young specialists. With the 100 KW electron beam power, the total thermal power of the facility is {approx}360 kW including the fission power of {approx}260 kW. The burnup of the fissile materials and the buildup of fission products continuously reduce the system reactivity during the operation, decrease the neutron flux level, and consequently impact the facility performance. To preserve the neutron flux level during the operation, the fuel assemblies should be added and shuffled for compensating the lost reactivity caused by burnup. Beryllium reflector could also be utilized to increase the fuel life time in the sub-critical core. This paper studies the fuel cycles and shuffling schemes of the fuel assemblies of the sub-critical assembly to preserve the system reactivity and the neutron flux level during the operation.

  11. System Engineering Status and Design Characteristics of Cold Neutron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Ki; Jung, H. S.; Wu, S. I.; Ahn, S. H.; Kim, Y. J

    2004-06-15

    This report has been issued as a result of the surveys of foreign state of the arts on cold neutron source, which was a activity of the project, 'Development of Systems for Cold Neutron Source' commenced on July, 2003. Review and analysis for systems characteristics of the foreign cold neutron source will be a good reference for the basic and detail design starting on the July, 2004. Since the cold neutron source adopts liquid hydrogen or deuterium as a moderator and special field of techniques such as cryogenic cooling system, high vacuum and gas handling, etc., the project started with the survey work in order to be familiar with the concept of the cold neutron source. The survey work was proceeded on the foreign cold neutron sources. This report includes characteristics of the several foreign cold neutron sources.

  12. Shielding the LANSCE [Los Alamos Neutron Scattering Center] 800-MeV spallation neutron source

    International Nuclear Information System (INIS)

    Neutrons produced by medium-energy (800-MeV) proton reactions at the Los Alamos Neutron Scattering Center spallation neutron source cause a variety of difficult shield problems. We describe the general shielding questions encountered at such a spallation source, and contrast spallation and reactor source shielding issues using an infinite slab-shield composed of 100 cm of iron and 15 cm of borated polyethylene. The calculations show that (for an incident spallation spectrum characteristic of neutrons leaking at 90 degrees from a tungsten target) high-energy neutrons dominate the dose at the shield surface. Secondary low-energy neutrons (produced by high-energy neutron attenuation) and attendant gamma-rays add significantly to the dose. The primary low-energy neutrons produced directly at the tungsten source contribute negligibly to the dose, and behave similarly to neutrons with a fission spectrum distribution. 8 refs., 10 figs

  13. Acceleration of Automated HI Source Extraction

    Science.gov (United States)

    Badenhorst, S. J.; Blyth, S.; Kuttel, M. M.

    2013-10-01

    We aim to enable fast automated extraction of neutral hydrogen (HI) sources from large survey data sets. This requires both handling the large files (>5 TB) to be produced by next-generation interferometers and acceleration of the source extraction algorithm. We develop an efficient multithreaded implementation of the A'Trous wavelet reconstruction algorithm, which we evaluate against the serial implementation in the DUCHAMP package. We also evaluate three memory management libraries (Mmap, Boost and Stxxl) that enable processing of data files too large to fit into main memory, to establish which provides the best performance.

  14. The Chinese Spallation Neutron Source Project

    International Nuclear Information System (INIS)

    The proposal of the Chinese Spallation Neutron Source (CSNS) project was granted in the beginning of 2002 after three review meetings, organized by the Chinese Academy of Sciences (CAS) and other scientific organizations. Physicists from the Institute of Physics (IP) and the Institute of High Energy Physics (IHEP), both belonging to CAS, consequently started a conceptual design and feasibility study. The CSNS plan calls for a 70-MeV H- linac and a 1.6 GeV rapid cycling synchrotron producing a proton current of 62.5 μA (100kW) at a 25 Hz repetition rate. It should be able to be upgraded to a higher beam power in its second phase. The CSNS target station design team, has initiated to conceptual design of the targetmoderator system based on the suggestions and comments from an international advisory team, in the first moderator-target planning meeting of CSNS project (21-26, April 2002 in Beijing). In consideration of the characteristics of the spallation neutron source, the budgets and possible requests for future users in China, five multi-purpose neutron scattering spectrometers were proposed as the first step

  15. A portable neutron/tunable X-ray source based on inertial electrostatic confinement

    International Nuclear Information System (INIS)

    Portable neutron sources are of strong interest for uses such as industrial neutron activation analysis and various medical research applications. The inertial electrostatic confinement (IEC) device under development at the University of Illinois is intended for such uses and also provides a tunable X-ray source (required reverse bias and added electron emitters). The IEC operates as an accelerator plasma-target type device, and when filled with deuterium presently provides 107∼2.5 MeV D-D fusion neutrons/s. D-T fill gas gives 14 MeV neutrons, with rates about 100 times that of D-D, but with the added complication of handling low levels of tritium. Research on higher yield versions now under development is described. Still, in the interim, the IEC, due to its compactness, portability, simplicity and flexibility offers a unique portable neutron/X-ray source

  16. Neutron source based on the TORNADO trap

    International Nuclear Information System (INIS)

    The TORNADO magnetic trap as a source of thermonuclear neutrons with 108 neutron per a pulse in the D-D reaction is considered. The construction of magnetic traps both with stationary and quasistationary modes of their operation is shown to be possible. The results of numerical calculation of the magnetic system parameters are given, analysis of permissible mechanical loads, turns displacements of and magnetic fields in the trap is carried out. Considerable decrease of pondermotive forces affecting the turns of an internal spiral when conserving thermo-insulating properties of the magnetic trap field is shown to be possible. The loads of the trap spiral magnet coils are shown to be also acceptable to form the stationary magnetic field of the 2 Tl order in the magnetic barrier

  17. Neutron diffractometers for structural biology at spallation neutron sources

    International Nuclear Information System (INIS)

    Spallation neutron sources are ideal for diffraction studies of proteins and oriented molecular complexes. With spoliation neutrons and their time dependent wavelength structure, it is easy to electronically select data with an optimal wavelength bandwidth and cover the whole Laue spectrum as time (wavelength) resolved snapshots. This optimized data quality with best peak-to-background ratios and provides adequate spatial and energy resolution to eliminate peak overlaps. The application of this concept will use choppers to select the desired Laue wavelength spectrum and employ focusing optics and large cylindrical 3He detectors to optimize data collection rates. Such a diffractometer will cover a Laue wavelength range from 1 to 5 Angstrom with a flight path length of 10m and an energy resolution of 0.25 Angstrom. Moderator concepts for maximal flux distribution within this energy range will be discussed using calculated flux profiles. Since the energy resolution required for such timed data collection in this super Laue techniques is not very high, the use of a linac only (LAMPF) spoliation target is an exciting possibility with an order of magnitude increase in flux

  18. Neutron diffractometers for structural biology at spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Schoenborn, B.P.; Pitcher, E. [Los Alamos National Laboratory, NM (United States)

    1994-12-31

    Spallation neutron sources are ideal for diffraction studies of proteins and oriented molecular complexes. With spoliation neutrons and their time dependent wavelength structure, it is easy to electronically select data with an optimal wavelength bandwidth and cover the whole Laue spectrum as time (wavelength) resolved snapshots. This optimized data quality with best peak-to-background ratios and provides adequate spatial and energy resolution to eliminate peak overlaps. The application of this concept will use choppers to select the desired Laue wavelength spectrum and employ focusing optics and large cylindrical {sup 3}He detectors to optimize data collection rates. Such a diffractometer will cover a Laue wavelength range from 1 to 5{Angstrom} with a flight path length of 10m and an energy resolution of 0.25{Angstrom}. Moderator concepts for maximal flux distribution within this energy range will be discussed using calculated flux profiles. Since the energy resolution required for such timed data collection in this super Laue techniques is not very high, the use of a linac only (LAMPF) spoliation target is an exciting possibility with an order of magnitude increase in flux.

  19. High-Power Linac for the Spallation Neutron Source

    Science.gov (United States)

    Rej, D. J.

    2002-04-01

    The Spallation Neutron Source (SNS) will be the world’s most intense source of neutrons for fundamental science and industrial applications. Design and construction of this facility, located at Oak Ridge, is a joint venture between six DOE laboratories. Construction began in 1999 and is currently ahead of the scheduled 2006 completion date. Injecting a high-power, pulsed proton beam into a mercury target produces neutrons. In this talk, we review the physics requirements, design, and status of the construction of the 1-GeV, 1.4-MW average power RF linac for SNS. The accelerator consists of a drift tube linac (DTL), a coupled-cavity linac (CCL), and a superconducting rf (SRF) linac. The phase and quadrupole settings are set to avoid structure and parametric resonances, with coherent resonances posing minimal risk for emittance growth. The DTL is 37 m long and accelerates the ions to 87 MeV. The CCL is 55 m long and accelerates the ions to 186 MeV. The rf structure design and stability for both the DTL and CCL have been validated with scale models. The SRF linac has a modular design to accelerate ions to 1000 MeV, with a straightforward upgrade to 1.3 GeV at a later date. 3D particle-in-cell simulations of beam dynamics are performed to validate performance. The accelerator utilizes 93 MW of pulsed power operating continuously at 60-Hz with an 8factor. Approximately one hundred 402.5 or 805-MHz klystrons, with outputs between 0.55 and 5 MW, are used. The klystrons are powered by a novel converter-modulator that takes advantage of recent advances in IGBT switch plate assemblies and low-loss material cores for boost transformer. Beam diagnostics include position, phase, profile, and current monitors. They are designed to enable accurate beam steering and matching, and to minimize beam loss that would lead to activation and prevent hands-on maintenance.

  20. New sources and instrumentation for neutrons in biology

    DEFF Research Database (Denmark)

    Teixeira, S.C.M.; Zaccai, G.; Ankner, J.;

    2008-01-01

    Neutron radiation offers significant advantages for the study of biological molecular structure and dynamics. A broad and significant effort towards instrumental and methodological development to facilitate biology experiments at neutron sources worldwide is reviewed.......Neutron radiation offers significant advantages for the study of biological molecular structure and dynamics. A broad and significant effort towards instrumental and methodological development to facilitate biology experiments at neutron sources worldwide is reviewed....

  1. LANL sunnyside experiment: Study of neutron production in accelerator-driven targets

    International Nuclear Information System (INIS)

    Measurements have been made of the neutron production in prototypic targets for accelerator driven systems. Studies were conducted on four target assemblies containing lead, lithium, tungsten, and a thorium-salt mixture. Integral data on total neutron production were obtained as well as more differential data on neutron leakage and neutron flux profiles in the blanket/moderator region. Data analysis on total neutron production is complete and shows excellent agreement with calculations using the LAHET/MCNP code system

  2. A status report on the advanced neutron source project

    International Nuclear Information System (INIS)

    Design work on the Advanced Neutron Source facilities has progressed significantly, with cost saving changes to the buildings and other systems. The cold source design has advanced considerably, and in addition design work has been initiated on the hot neutron source and on a positron source. (J.P.N.)

  3. Preliminary energy-filtering neutron imaging with time-of-flight method on PKUNIFTY: A compact accelerator based neutron imaging facility at Peking University

    Science.gov (United States)

    Wang, Hu; Zou, Yubin; Wen, Weiwei; Lu, Yuanrong; Guo, Zhiyu

    2016-07-01

    Peking University Neutron Imaging Facility (PKUNIFTY) works on an accelerator-based neutron source with a repetition period of 10 ms and pulse duration of 0.4 ms, which has a rather low Cd ratio. To improve the effective Cd ratio and thus improve the detection capability of the facility, energy-filtering neutron imaging was realized with the intensified CCD camera and time-of-flight (TOF) method. Time structure of the pulsed neutron source was firstly simulated with Geant4, and the simulation result was evaluated with experiment. Both simulation and experiment results indicated that fast neutrons and epithermal neutrons were concentrated in the first 0.8 ms of each pulse period; meanwhile in the period of 0.8-2.0 ms only thermal neutrons existed. Based on this result, neutron images with and without energy filtering were acquired respectively, and it showed that detection capability of PKUNIFTY was improved with setting the exposure interval as 0.8-2.0 ms, especially for materials with strong moderating capability.

  4. Study on the production of medical RIs like 99Mo based on accelerator neutrons generated by C(d,n))

    International Nuclear Information System (INIS)

    This paper introduces the development state of the manufacturing method for 99mTc that satisfies the conditions for radioactive preparations. In this process, using the high-speed neutrons obtained in C(d,n) reaction due to the deuterons of approximately 40 MeV from an accelerator, 99Mo is obtained based on 100Mo(n,2n) reaction. The authors considered cyclotron as a prototype accelerator, and used a thermal separation process to separate/purify and produce the quality 99mTc from the generated 99Mo with low specific radioactivity. This paper also introduces the attractiveness of fast neutrons as 'new neutron source to supplement reactor neutrons,' by referring to the case of the production of 67Cu expected as therapeutic isotope, based on 68Zn(n,x)67Cu reaction. (A.O.)

  5. Construction and operation of the Spallation Neutron Source: Draft environmental impact statement. Volume 1

    International Nuclear Information System (INIS)

    DOE proposes to construct and operate a state-of-the-art, short-pulsed spallation neutron source comprised of an ion source, a linear accelerator, a proton accumulator ring, and an experiment building containing a liquid mercury target and a suite of neutron scattering instrumentation. The proposed Spallation Neutron Source would be designed to operate at a proton beam power of 1 megawatt. The design would accommodate future upgrades to a peak operating power of 4 megawatts. These upgrades may include construction of a second proton accumulation ring and a second target. The US needs a high-flux, short-pulsed neutron source to provide the scientific and industrial research communities with a much more intense source of pulsed neutrons for neutron scattering research than is currently available, and to assure the availability of a state-of-the-art facility in the decades ahead. This next-generation neutron source would create new scientific and engineering opportunities. In addition, it would help replace the neutron science capacity that will be lost by the eventual shutdown of existing sources as they reach the end of their useful operating lives in the first half of the next century. This document analyzes the potential environmental impacts from the proposed action and the alternatives. The analysis assumes a facility operating at a power of 1 MW and 4 MW over the life of the facility. The two primary alternatives analyzed in this EIS are: the proposed action (to proceed with building the Spallation Neutron Source) and the No-Action Alternative. The No-Action Alternative describes the expected condition of the environment if no action were taken. Four siting alternatives for the Spallation Neutron Source are evaluated: Oak Ridge National Laboratory, Oak Ridge, TN, (preferred alternative); Argonne National Laboratory, Argonne, IL (US); Brookhaven National Laboratory, Upton, NY; and Los Alamos National Laboratory, Los Alamos, NM

  6. UCN Source at an External Beam of Thermal Neutrons

    OpenAIRE

    2015-01-01

    We propose a new method for production of ultracold neutrons (UCNs) in superfluid helium. The principal idea consists in installing a helium UCN source into an external beam of thermal or cold neutrons and in surrounding this source with a solid methane moderator/reflector cooled down to ~4 K. The moderator plays the role of an external source of cold neutrons needed to produce UCNs. The flux of accumulated neutrons could exceed the flux of incident neutrons due to their numerous reflections ...

  7. Bright Laser-Driven Neutron Source Based on the Relativistic Transparency of Solids

    Science.gov (United States)

    Roth, M.; Jung, D.; Falk, K.; Guler, N.; Deppert, O.; Devlin, M.; Favalli, A.; Fernandez, J.; Gautier, D.; Geissel, M.; Haight, R.; Hamilton, C. E.; Hegelich, B. M.; Johnson, R. P.; Merrill, F.; Schaumann, G.; Schoenberg, K.; Schollmeier, M.; Shimada, T.; Taddeucci, T.; Tybo, J. L.; Wagner, F.; Wender, S. A.; Wilde, C. H.; Wurden, G. A.

    2013-01-01

    Neutrons are unique particles to probe samples in many fields of research ranging from biology to material sciences to engineering and security applications. Access to bright, pulsed sources is currently limited to large accelerator facilities and there has been a growing need for compact sources over the recent years. Short pulse laser driven neutron sources could be a compact and relatively cheap way to produce neutrons with energies in excess of 10 MeV. For more than a decade experiments have tried to obtain neutron numbers sufficient for applications. Our recent experiments demonstrated an ion acceleration mechanism based on the concept of relativistic transparency. Using this new mechanism, we produced an intense beam of high energy (up to 170 MeV) deuterons directed into a Be converter to produce a forward peaked neutron flux with a record yield, on the order of 1010n/sr. We present results comparing the two acceleration mechanisms and the first short pulse laser generated neutron radiograph.

  8. Assessment of neutron dose in Indus accelerator complex using CR-39 SSNTD

    International Nuclear Information System (INIS)

    Indus accelerator complex (IAC) consists of two synchrotron radiation sources namely Indus-1 and Indus-2. The radiation environment here is mainly due to Bremsstrahlung and photo-neutrons. Major problems faced in neutron detection in IAC are the severely pulsed nature and gamma (Bremsstrahlung) interference. Thus, to assess the neutron dose rates in the accessible and inaccessible areas of IAC, passive integrating type neutron detectors CR-39 and bubble detectors are used. The dose rates observed at microtron body; booster injection and extraction septum are significant (few mSv/h) when compared to other locations in IAC. From bubble detector data, it can be seen that the dose rate during injection is high (maximum 112 μSv/h) compared with storage mode (maximum 2.6 μSv/h) indicating high beam loss during injection. During the injection, the personnel are not allowed in these areas due to high radiation doses on account of the beam loss. The neutron dose rates observed for accessible areas are three orders of magnitude less than the inaccessible areas in the complex. (author)

  9. Summary report of the consultants' meeting on neutron sources spectra for EXFOR

    International Nuclear Information System (INIS)

    The participants highlighted the importance of complementing the averaged cross section data already stored in EXFOR by the incident neutron energy spectra. They shared their experience on measurement and simulation of neutron fields produced at reactors and accelerators over a wide energy range. The source characteristics, format and rules needed for storage in EXFOR were discussed. The participants submitted the numerical information on spectra that will essentially increase the number of 'complete' data sets in EXFOR. The report additionally provides an overview of (i) neutron production cross sections and thick target yields missing from the EXFOR database; (ii) codes for neutron spectra calculations; (iii) informational resources for reactor, radioactive and spallation neutron sources; (iv) codes for spectrum unfolding and (v) EXFOR compilation rules for the Maxwellian averaged cross sections measured for the reactor and astrophysical applications. (author)

  10. A neutron booster for spallation sources—application to accelerator driven systems and isotope production

    Science.gov (United States)

    Galy, J.; Magill, J.; Van Dam, H.; Valko, J.

    2002-06-01

    One can design a critical system with fissile material in the form of a thin layer on the inner surface of a cylindrical neutron moderator such as graphite or beryllium. Recently, we have investigated the properties of critical and near critical systems based on the use of thin actinide layers of uranium, plutonium and americium. The thickness of the required fissile layer depends on the type of fissile material, its concentration in the layer and on the geometrical arrangement, but is typically in the μm-mm range. The resulting total mass of fissile material can be as low as 100 g. Thin fissile layers have a variety of applications in nuclear technology—for example in the design neutron amplifiers for medical applications and "fast" islands in thermal reactors for waste incineration. In the present paper, we investigate the properties of a neutron booster unit for spallation sources and isotope production. In those applications a layer of fissile material surrounds the spallation source. Such a module could be developed for spallation targets foreseen in the MYRRHA (L. Van Den Durpel, H. Aı̈t Abderrahim, P. D'hondt, G. Minsart, J.L. Bellefontaine, S. Bodart, B. Ponsard, F. Vermeersch, W. Wacquier. A prototype accelerator driven system in Belgium: the Myrrha project, Technical Committee Meeting on Feasibility and Motivation for Hybrid concepts for Nuclear Energy generation and Transmutation, Madrid, Spain, September 17-19, 1997 [1]). or MEGAPIE (M. Salvatores, G.S. Bauer, G. Heusener. The MEGAPIE initiative: executive outline and status as per November 1999, MPO-1-GB-6/0_GB, 1999 [2]) projects. With a neutron multiplication factor of the booster unit in the range 10-20 (i.e. with a keff of 0.9-0.95), considerably less powerful accelerators would be required to obtain the desired neutron flux. Instead of the powerful accelerators with proton energies of 1 GeV and currents of 10 mA foreseen for accelerator driven systems, similar neutron fluxes can be obtained

  11. Radiation problems expected for the German spallation neutron source

    International Nuclear Information System (INIS)

    The German project for the construction of a Spallation Neutron Source with high proton beam power (5.5 MW) will have to cope with a number of radiation problems. The present report describes these problems and proposes solutions for keeping exposures for the staff and release of activity and radiation into the environment as low as reasonably achievable. It is shown that the strict requirements of the German radiation protection regulations can be met. The main problem will be the exposure of maintenance personnel to remanent gamma radiation, as is the case at existing proton accelerators. Closed ventilation and cooling systems will reduce the release of (mainly short-lived) activity to acceptable levels. Shielding requirements for different sections are discussed, and it is demonstrated by calculations and extrapolations from experiments that fence-post doses well below 150 mrem/y can be obtained at distances of the order of 100 metres from the principal source points. The radiation protection system proposed for the Spallation Neutron Source is discussed, in particular the needs for monitor systems and a central radiation protection data base and alarm system. (orig.)

  12. A review of ion sources for medical accelerators (invited).

    Science.gov (United States)

    Muramatsu, M; Kitagawa, A

    2012-02-01

    under development for the boron neutron capture therapy. This treatment is conventionally demonstrated by a nuclear reactor, but it is strongly expected to replace the reactor by the accelerator. We report status of ion source for medical application and such scope for further developments. PMID:22380341

  13. Field Ion Source Development for Neutron Generators

    Energy Technology Data Exchange (ETDEWEB)

    B. Bargsten Johnson; P. R. Schwoebel; C. E. Holland; P. J. Resnick; K. L. Hertz; D. L. Chichester

    2012-01-01

    An ion source based on the principles of electrostatic field desorption is being developed to improve the performance of existing compact neutron generators. The ion source is an array of gated metal tips derived from field electron emitter array microfabrication technology. A comprehensive summary of development and experimental activities is presented. Many structural modifications to the arrays have been incorporated to achieve higher tip operating fields, while lowering fields at the gate electrode to prevent gate field electron emission which initiates electrical breakdown in the array. The latest focus of fabrication activities has been on rounding the gate electrode edge and surrounding the gate electrode with dielectric material. Array testing results have indicated a steady progression of increased array tip operating fields with each new design tested. The latest arrays have consistently achieved fields beyond those required for the onset of deuterium desorption ({approx}20 V/nm), and have demonstrated the desorption of deuterium at fields up to 36 V/nm. The number of ions desorbed from an array has been quantified, and field desorption of metal tip substrate material from array tips has been observed for the first time. Gas-phase field ionization studies with {approx}10,000 tip arrays have achieved deuterium ion currents of {approx}50 nA. Neutron production by field ionization has yielded {approx}10{sup 2} n/s from {approx}1 mm{sup 2} of array area using the deuterium-deuterium fusion reaction at 90 kV.

  14. Field ion source development for neutron generators

    Energy Technology Data Exchange (ETDEWEB)

    Bargsten Johnson, B. [University of New Mexico, Albuquerque, NM 87131 (United States); Schwoebel, P.R., E-mail: schwoebel@chtm.unm.edu [University of New Mexico, Albuquerque, NM 87131 (United States); Holland, C.E. [SRI International, Menlo Park, CA 94025 (United States); Resnick, P.J. [Sandia National Laboratories, Albuquerque, NM 87123 (United States); Hertz, K.L. [Sandia National Laboratories, Livermore, CA 94551 (United States); Chichester, D.L. [Idaho National Laboratory, Idaho Falls, ID 83415 (United States)

    2012-01-21

    An ion source based on the principles of electrostatic field desorption is being developed to improve the performance of existing compact neutron generators. The ion source is an array of gated metal tips derived from field electron emitter array microfabrication technology. A comprehensive summary of development and experimental activities is presented. Many structural modifications to the arrays have been incorporated to achieve higher tip operating fields, while lowering fields at the gate electrode to prevent gate field electron emission which initiates electrical breakdown in the array. The latest focus of fabrication activities has been on rounding the gate electrode edge and surrounding the gate electrode with dielectric material. Array testing results have indicated a steady progression of increased array tip operating fields with each new design tested. The latest arrays have consistently achieved fields beyond those required for the onset of deuterium desorption ({approx}20 V/nm), and have demonstrated the desorption of deuterium at fields up to 36 V/nm. The number of ions desorbed from an array has been quantified, and field desorption of metal tip substrate material from array tips has been observed for the first time. Gas-phase field ionization studies with {approx}10,000 tip arrays have achieved deuterium ion currents of {approx}50 nA. Neutron production by field ionization has yielded {approx}10{sup 2} n/s from {approx}1 mm{sup 2} of array area using the deuterium-deuterium fusion reaction at 90 kV.

  15. Source driven breeding thermal power reactors, Pt. 2. Using lithium-free neutron sources

    International Nuclear Information System (INIS)

    The feasibility of fusion devices operating in the semi-catalyzed deuterium (SCD) mode and of high energy proton accelerators to provide the neutron sources for driving subcritical breeding light water power reactors is assessed. The assessment is done by studying the energy balance of the resulting source driven light water reactors (SDLWR) and comparing it with the energy balance of the reference light water hybrid reactors (LWHR) driven by a D-T neutron source (DT-LWHR). The conditions the non-DT neutron sources should satisfy in order to make the SDLWR viable power reactors are identified. It is found that in order for a SCD-LWHR to have the same overall efficiency as a DT-LWHR, the fusion energy gain of the SCD device should be at least one half that of the DT device. The efficiency of ADLWRs using uranium targets is comparable with that of DT-LWHRs having a fusion energy gain of unity. Advantages and disadvantages of the DT-LWHR, SCD-LWHR and ADLWR are discussed

  16. The neutron dose equivalent around high energy medical electron linear accelerators

    Directory of Open Access Journals (Sweden)

    Poje Marina

    2014-01-01

    Full Text Available The measurement of neutron dose equivalent was made in four dual energy linear accelerator rooms. Two of the rooms were reconstructed after decommissioning of 60Co units, so the main limitation was the space. The measurements were performed by a nuclear track etched detectors LR-115 associated with the converter (radiator that consist of 10B and with the active neutron detector Thermo BIOREM FHT 742. The detectors were set at several locations to evaluate the neutron ambient dose equivalent and/or neutron dose rate to which medical personnel could be exposed. Also, the neutron dose dependence on collimator aperture was analyzed. The obtained neutron dose rates outside the accelerator rooms were several times smaller than the neutron dose rates inside the accelerator rooms. Nevertheless, the measured neutron dose equivalent was not negligible from the aspect of the personal dosimetry with almost 2 mSv a year per person in the areas occupied by staff (conservative estimation. In rooms with 15 MV accelerators, the neutron exposure to the personnel was significantly lower than in the rooms having 18 MV accelerators installed. It was even more pronounced in the room reconstructed after the 60Co decommissioning. This study confirms that shielding from the neutron radiation should be considered when building vaults for high energy linear accelerators, especially when the space constraints exist.

  17. Novel neutron focusing mirrors for compact neutron sources

    OpenAIRE

    Gubarev, M. V.; Zavlin, V. E.; Katz, R.; Resta, G.; Robertson, L; Crow, L.; Ramsey, B. D.; Khaykovich, Boris; Liu, DaZhi; Moncton, David E.

    2012-01-01

    We demonstrated neutron beam focusing and neutron imaging using axisymmetric optics, based on pairs of confocal ellipsoid and hyperboloid mirrors. Such systems, known as Wolter mirrors, are commonly used in x-ray telescopes. A system containing four nested Ni mirror pairs was implemented and tested by focusing a polychromatic neutron beam at the MIT Reactor and conducting an imaging experiment at HFIR. The major advantage of the Wolter mirrors is the possibility of nesting for large angular c...

  18. Advanced spallation neutron sources for condensed matter research

    International Nuclear Information System (INIS)

    Advanced spallation neutron sources afford significant advantages over existing high flux reactors. The effective flux is much greater than that currently available with reactor sources. A ten-fold increase in neutron flux will be a major benefit to a wide range of condensed matter studies, and it will realise important experiments that are marginal at reactor sources. Moreover, the high intensity of epithermal neutrons open new vistas in studies of electronic states and molecular vibrations. (author)

  19. Time collimation for elastic neutron scattering at a pulsed source

    International Nuclear Information System (INIS)

    Conditions for carrying out elastic neutron scattering experiments using the time-of-flight technique are considered. It is shown, that the employment of time dependent neutron beam collimation in the source-sample flight path increases the luminosity of the spectrometer under certain resolution restrictions. Time collimation modes are proposed for small-angle scattering and neutron reflection. (author) 8 figs., 3 refs

  20. PGNAA neutron source moderation setup optimization

    OpenAIRE

    Zhang, Jinzhao; Tuo, Xianguo

    2013-01-01

    Monte Carlo simulations were carried out to design a prompt {\\gamma}-ray neutron activation analysis (PGNAA) thermal neutron output setup using MCNP5 computer code. In these simulations the moderator materials, reflective materials and structure of the PGNAA 252Cf neutrons of thermal neutron output setup were optimized. Results of the calcuations revealed that the thin layer paraffin and the thick layer of heavy water moderated effect is best for 252Cf neutrons spectrum. The new design compar...

  1. Fission, spallation or fusion-based neutron sources

    Indian Academy of Sciences (India)

    Kurt N Clausen

    2008-10-01

    In this paper the most promising technology for high power neutron sources is briefly discussed. The conclusion is that the route to high power neutron sources in the foreseeable future is spallation – short or long pulse or even CW – all of these sources will have areas in which they excel.

  2. Spectrum of isotopic neutron sources inside concrete wall spherical cavities

    International Nuclear Information System (INIS)

    The neutron spectra of 252Cf/D2O, 140LaBe, 252Cf, 238Pu18O2, 241AmB, 241AmBe, 226RaBe and 239PuBe isotopic neutron sources due to room-return have been determined for various source-to-detector distances in concrete spherical cavities of different radius. Changes in the amount of thermal neutrons (E≤0.414eV) were analyzed to estimate, for each neutron source, the coefficient that relates the neutron source strength and room surface area with the thermal neutron fluence rates. The study was carried out using Monte Carlo methods for 200, 400, 500, 800, 1000, 1200 and 1500-cm-radius spherical cavity in vacuum; cavities are 100-cm-thick concrete. Point sources were located at the center of cavity and neutron spectra were calculated at several source-to-detector distances along the cavity radius. The thermal neutron contribution was thereby evaluated. From these calculations a weighted coefficient value that relates the thermal neutron fluence with the neutron source strength and the total inner area surface of the cavity was estimated to be 3.76±0.03

  3. Direct measurement of the inelastic neutron acceleration by 177mLu

    Directory of Open Access Journals (Sweden)

    Menelle A.

    2010-03-01

    Full Text Available The inelastic neutron acceleration (INNA cross section on the long-lived isomer state of 177mLu has been measured from a new isomeric target using a direct method. The detection of high energy neutrons has been performed using a specially designed setup and a cold neutron beam at the ORPHEE reactor facility in Saclay.

  4. Improvements to the internal and external antenna H(-) ion sources at the Spallation Neutron Source.

    Science.gov (United States)

    Welton, R F; Dudnikov, V G; Han, B X; Murray, S N; Pennisi, T R; Pillar, C; Santana, M; Stockli, M P; Turvey, M W

    2014-02-01

    The Spallation Neutron Source (SNS), a large scale neutron production facility, routinely operates with 30-40 mA peak current in the linac. Recent measurements have shown that our RF-driven internal antenna, Cs-enhanced, multi-cusp ion sources injects ∼55 mA of H(-) beam current (∼1 ms, 60 Hz) at 65-kV into a Radio Frequency Quadrupole (RFQ) accelerator through a closely coupled electrostatic Low-Energy Beam Transport system. Over the last several years a decrease in RFQ transmission and issues with internal antennas has stimulated source development at the SNS both for the internal and external antenna ion sources. This report discusses progress in improving internal antenna reliability, H(-) yield improvements which resulted from modifications to the outlet aperture assembly (applicable to both internal and external antenna sources) and studies made of the long standing problem of beam persistence with the external antenna source. The current status of the external antenna ion source will also be presented.

  5. Ion sources for RFQ accelerators and for cyclotrons

    International Nuclear Information System (INIS)

    Ion sources used in conjunction with low energy accelerators, either RF quadrupole linacs or small cyclotrons, are reviewed. The topics covered include low energy accelerators used as injectors to larger accelerators, ion sources for low and medium currents of heavy ions, high-current heavy ion sources, ion sources for pulsed high currents of light ions, and new developments in ion sources such as beams of radioactive ions

  6. Research activities on structure materials of spallation neutron source at SINQ

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, G.S.; Dai, Y. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    With the growing interests on powerful spallation neutron sources, especially with liquid metal targets, and accelerator driven energy systems, spallation materials science and technology have been received wide attention. At SINQ, material research activities are focused on: a) liquid metal corrosion; b) radiation damage; and c) interaction of corrosion and radiation damage. (author) 1 fig., refs.

  7. Proceedings of the workshop on ion source issues relevant to a pulsed spallation neutron source: Part 1: Workshop summary

    International Nuclear Information System (INIS)

    The workshop reviewed the ion-source requirements for high-power accelerator-driven spallation neutron facilities, and the performance of existing ion sources. Proposals for new facilities in the 1- to 5-MW range call for a widely differing set of ion-source requirements. For example, the source peak current requirements vary from 40 mA to 150 mA, while the duty factor ranges from 1% to 9%. Much of the workshop discussion centered on the state-of-the-art of negative hydrogen ion source (H-) technology and the present experience with Penning and volume sources. In addition, other ion source technologies, for positive ions or CW applications were reviewed. Some of these sources have been operational at existing accelerator complexes and some are in the source-development stage on test stands

  8. Ion sources for high-power hadron accelerators

    OpenAIRE

    Faircloth, Dan

    2013-01-01

    Ion sources are a critical component of all particle accelerators. They create the initial beam that is accelerated by the rest of the machine. This paper will introduce the many methods of creating a beam for high-power hadron accelerators. A brief introduction to some of the relevant concepts of plasma physics and beam formation is given. The different types of ion source used in accelerators today are examined. Positive ion sources for producing H+ ions and multiply charged heavy ions are ...

  9. Neutron leakage from Pb and Bc spherical shells with 14 MeV central neutron source

    International Nuclear Information System (INIS)

    Results of measuring neutron leakage from spherical shells of different thickness, made of Pb and Be with a point neutron source in the sphere centrum are presented. The experiment results are compared to calculations according to different programs using data of various nuclear data libraies. The comparison has shown that all the calculations understate the neutron leakage from Pb assmebly. 9 refs.; 2 tabs

  10. UCN Source at an External Beam of Thermal Neutrons

    Directory of Open Access Journals (Sweden)

    E. V. Lychagin

    2015-01-01

    Full Text Available We propose a new method for production of ultracold neutrons (UCNs in superfluid helium. The principal idea consists in installing a helium UCN source into an external beam of thermal or cold neutrons and in surrounding this source with a solid methane moderator/reflector cooled down to ~4 K. The moderator plays the role of an external source of cold neutrons needed to produce UCNs. The flux of accumulated neutrons could exceed the flux of incident neutrons due to their numerous reflections from methane; also the source size could be significantly larger than the incident beam diameter. We provide preliminary calculations of cooling of neutrons. These calculations show that such a source being installed at an intense source of thermal or cold neutrons like the ILL or PIK reactor or the ESS spallation source could provide the UCN density 105 cm−3, the production rate 107 UCN/s−1. Main advantages of such an UCN source include its low radiative and thermal load, relatively low cost, and convenient accessibility for any maintenance. We have carried out an experiment on cooling of thermal neutrons in a methane cavity. The data confirm the results of our calculations of the spectrum and flux of neutrons in the methane cavity.

  11. Medical Isotope Production Analyses In KIPT Neutron Source Facility

    Energy Technology Data Exchange (ETDEWEB)

    Talamo, Alberto [Argonne National Lab. (ANL), Argonne, IL (United States); Gohar, Yousry [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-01-01

    Medical isotope production analyses in Kharkov Institute of Physics and Technology (KIPT) neutron source facility were performed to include the details of the irradiation cassette and the self-shielding effect. An updated detailed model of the facility was used for the analyses. The facility consists of an accelerator-driven system (ADS), which has a subcritical assembly using low-enriched uranium fuel elements with a beryllium-graphite reflector. The beryllium assemblies of the reflector have the same outer geometry as the fuel elements, which permits loading the subcritical assembly with different number of fuel elements without impacting the reflector performance. The subcritical assembly is driven by an external neutron source generated from the interaction of 100-kW electron beam with a tungsten target. The facility construction was completed at the end of 2015, and it is planned to start the operation during the year of 2016. It is the first ADS in the world, which has a coolant system for removing the generated fission power. Argonne National Laboratory has developed the design concept and performed extensive design analyses for the facility including its utilization for the production of different radioactive medical isotopes. 99Mo is the parent isotope of 99mTc, which is the most commonly used medical radioactive isotope. Detailed analyses were performed to define the optimal sample irradiation location and the generated activity, for several radioactive medical isotopes, as a function of the irradiation time.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-15

    Purpose: Linear accelerators producing photons above 10 MeV may induce photonuclear reactions in high Z components of the accelerator. These liberated neutrons can then activate the structural components of the accelerator and other materials in the beam path through neutron capture reactions. The induced activity within the accelerator may contribute to additional dose to both patients and personnel. This project seeks to determine the total activity and activity per activated isotope following irradiation in different Varian accelerators at energies above 10 MeV. Methods: A Varian 21IX accelerator was used to irradiate a 30 cm × 30 cm × 20 cm solid water phantom with 15 MV x-rays. The phantom was placed at an SSD of 100 cm and at the center of a 20 cm × 20 cm field. Activation induced gamma spectra were acquired over a 5 minute interval after 1 and 15 minutes from completion of the irradiation. All measurements were made using a CANBERRA Falcon 5000 Portable HPGe detector. The majority of measurements were made in scattering geometry with the detector situated at 90° to the incident beam, 30 cm from the side of the phantom and approximately 10 cm from the top. A 5 minute background count was acquired and automatically subtracted from all subsequent measurements. Photon spectra were acquired for both open and MLC fields. Results: Based on spectral signatures, nuclides have been identified and their activities calculated for both open and MLC fields. Preliminary analyses suggest that activities from the activation products in the microcurie range. Conclusion: Activation isotopes have been identified and their relative activities determined. These activities are only gross estimates since efficiencies have not been determined for this source-detector geometry. Current efforts are focused on accurate determination of detector efficiencies using Monte Carlo calculations.

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

    International Nuclear Information System (INIS)

    Purpose: Linear accelerators producing photons above 10 MeV may induce photonuclear reactions in high Z components of the accelerator. These liberated neutrons can then activate the structural components of the accelerator and other materials in the beam path through neutron capture reactions. The induced activity within the accelerator may contribute to additional dose to both patients and personnel. This project seeks to determine the total activity and activity per activated isotope following irradiation in different Varian accelerators at energies above 10 MeV. Methods: A Varian 21IX accelerator was used to irradiate a 30 cm × 30 cm × 20 cm solid water phantom with 15 MV x-rays. The phantom was placed at an SSD of 100 cm and at the center of a 20 cm × 20 cm field. Activation induced gamma spectra were acquired over a 5 minute interval after 1 and 15 minutes from completion of the irradiation. All measurements were made using a CANBERRA Falcon 5000 Portable HPGe detector. The majority of measurements were made in scattering geometry with the detector situated at 90° to the incident beam, 30 cm from the side of the phantom and approximately 10 cm from the top. A 5 minute background count was acquired and automatically subtracted from all subsequent measurements. Photon spectra were acquired for both open and MLC fields. Results: Based on spectral signatures, nuclides have been identified and their activities calculated for both open and MLC fields. Preliminary analyses suggest that activities from the activation products in the microcurie range. Conclusion: Activation isotopes have been identified and their relative activities determined. These activities are only gross estimates since efficiencies have not been determined for this source-detector geometry. Current efforts are focused on accurate determination of detector efficiencies using Monte Carlo calculations

  14. Power spectral analysis for a subcritical reactor system driven by a pulsed spallation neutron source

    International Nuclear Information System (INIS)

    A series of power spectral analyses for a thermal subcritical reactor system driven by a pulsed spallation neutron source was carried out at Kyoto University Critical Assembly (KUCA), to determine the prompt-neutron decay constant of the Accelerator-Driven System (ADS). High-energy protons (100 MeV) obtained from the fixed field alternating gradient accelerator were injected onto a lead-bismuth target, whereby the spallation neutrons were generated. In the cross-power spectral density between time-sequence signal data of two neutron detectors, many delta-function-like peaks at the integral multiple of pulse repetition frequency could be observed. However, no continuous reactor-noise component could be measured. This is because these detectors have too high count-rate to be placed closely to the core. From the point data of these delta-function-like peaks, the prompt-neutron decay constant could be determined. At a slightly subcritical state, the decay constant was consistent with that obtained by a previous power spectral analysis for a pulsed 14 MeV neutron source and by a pulsed neutron experiment. At another deeply subcritical state, however, the present analysis leads to an underestimate of the decay constant. (author)

  15. PREFACE: Neutrino physics at spallation neutron sources

    Science.gov (United States)

    Avignone, F. T.; Chatterjee, L.; Efremenko, Y. V.; Strayer, M.

    2003-11-01

    Unique because of their super-light masses and tiny interaction cross sections, neutrinos combine fundamental physics on the scale of the miniscule with macroscopic physics on the scale of the cosmos. Starting from the ignition of the primal p-p chain of stellar and solar fusion reactions that signal star-birth, these elementary leptons (neutrinos) are also critical players in the life-cycles and explosive deaths of massive stars and the production and disbursement of heavy elements. Stepping beyond their importance in solar, stellar and supernova astrophysics, neutrino interactions and properties influence the evolution, dynamics and symmetries of the cosmos as a whole. Further, they serve as valuable probes of its material content at various levels of structure from atoms and nuclei to valence and sea quarks. In the light of the multitude of physics phenomena that neutrinos influence, it is imperative to enhance our understanding of neutrino interactions and properties to the maximum. This is accentuated by the recent evidence of finite neutrino mass and flavour mixing between generations that reverberates on the plethora of physics that neutrinos influence. Laboratory experiments using intense neutrino fluxes would allow precision measurements and determination of important neutrino reaction rates. These can then complement atmospheric, solar and reactor experiments that have enriched so valuably our understanding of the neutrino and its repertoire of physics applications. In particular, intermediate energy neutrino experiments can provide critical information on stellar and solar astrophysical processes, along with advancing our knowledge of nuclear structure, sub-nuclear physics and fundamental symmetries. So where should we look for such intense neutrino sources? Spallation neutron facilities by their design are sources of intense neutrino pulses that are produced as a by-product of neutron spallation. These neutrino sources could serve as unique laboratories

  16. The Linac Cooherent Light Source (LCLS) Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Juhao; Emma, P.; /SLAC

    2007-03-21

    The Linac Coherent Light Source (LCLS) is a SASE x-ray Free-Electron Laser (FEL) based on the final kilometer of the Stanford Linear Accelerator. Such an FEL requires a high energy, high brightness electron beam to drive the FEL instability to saturation. When fed by an RF-photocathode gun, and modified to include two bunch compressor chicanes, the SLAC linac will provide such a high quality beam at 14 GeV and 1-{micro}m normalized emittance. In this paper, we report on recent linac studies, including beam stability and tolerances, longitudinal and transverse feedback systems, conventional and time-resolved diagnostics, and beam collimation systems. Construction and installation of the injector through first bunch compressor will be completed by December 2006, and electron commissioning is scheduled to begin in January of 2007.

  17. Studies and modeling of cold neutron sources; Etude et modelisation des sources froides de neutron

    Energy Technology Data Exchange (ETDEWEB)

    Campioni, G

    2004-11-15

    With the purpose of updating knowledge in the fields of cold neutron sources, the work of this thesis has been run according to the 3 following axes. First, the gathering of specific information forming the materials of this work. This set of knowledge covers the following fields: cold neutron, cross-sections for the different cold moderators, flux slowing down, different measurements of the cold flux and finally, issues in the thermal analysis of the problem. Secondly, the study and development of suitable computation tools. After an analysis of the problem, several tools have been planed, implemented and tested in the 3-dimensional radiation transport code Tripoli-4. In particular, a module of uncoupling, integrated in the official version of Tripoli-4, can perform Monte-Carlo parametric studies with a spare factor of Cpu time fetching 50 times. A module of coupling, simulating neutron guides, has also been developed and implemented in the Monte-Carlo code McStas. Thirdly, achieving a complete study for the validation of the installed calculation chain. These studies focus on 3 cold sources currently functioning: SP1 from Orphee reactor and 2 other sources (SFH and SFV) from the HFR at the Laue Langevin Institute. These studies give examples of problems and methods for the design of future cold sources.

  18. Room-temperature LINAC structures for the spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Billen, J. H. (James H.); Young, L. M. (Lloyd M.); Kurennoy, S. (Sergey); Crandall, K. R. (Kenneth R.)

    2001-04-01

    Los Alamos National Laboratory is building room-temperature rf accelerating structures for the Spallation Neutron Source (SNS). These structures, for H{sup -} ions, consist of six 402.5-MHz, 2-MW drift-tube linac (DTL) tanks from 2.5 to 87 MeV followed by four 805-MHz, 4-MW coupled-cavity linac (CCL) modules to 186 MeV. The DTL uses permanent magnet quadrupoles inside the drift tubes arranged in a 6{beta}{lambda} FFODDO lattice with every third drift tube available for diagnostics and steering. The CCL uses a 13{beta}{lambda} FODO electromagnetic quadrupole lattice. Diagnostics and magnets occupy the 2.5{beta}{lambda} spaces between 8-cavity segments. This paper discusses design of the rf cavities and low-power modeling work.

  19. An accelerator-based neutron microbeam system for studies of radiation effects

    OpenAIRE

    Xu, Yanping; Randers-Pehrson, Gerhard; Marino, Stephen A.; Bigelow, Alan W.; Akselrod, Mark S.; Sykora, Jeff G.; Brenner, David J.

    2010-01-01

    A novel neutron microbeam is being developed at the Radiological Research Accelerator Facility (RARAF) of Columbia University. The RARAF microbeam facility has been used for studies of radiation bystander effects in mammalian cells for many years. Now a prototype neutron microbeam is being developed that can be used for bystander effect studies. The neutron microbeam design here is based on the existing charged particle microbeam technology at the RARAF. The principle of the neutron microbeam...

  20. LENS: A New Pulsed Neutron Source for Research and Education

    OpenAIRE

    Leuschner, M.; Baxter, D. V.; Cameron, J. M.; Derenchuk, V.; Lavelle, C.; Lone, A; Nann, H.; Rinckel, T.; Snow, W. M.

    2005-01-01

    A new pulsed neutron source is under construction at the Indiana University Cyclotron Facility (IUCF). Neutrons are produced via (p,n) reactions by a low-energy proton beam incident on a thin beryllium target. The source is tightly coupled to a cold methane moderator held at a temperature of 20 K or below. The resulting time-averaged cold neutron flux is expected to be comparable to that of the Intense Pulsed Neutron Source (IPNS) facility at Argonne National Laboratory. The initial experimen...

  1. rf improvements for Spallation Neutron Source H- ion sourcea)

    Science.gov (United States)

    Kang, Y. W.; Fuja, R.; Goulding, R. H.; Hardek, T.; Lee, S.-W.; McCarthy, M. P.; Piller, M. C.; Shin, K.; Stockli, M. P.; Welton, R. F.

    2010-02-01

    The Spallation Neutron Source at Oak Ridge National Laboratory is ramping up the accelerated proton beam power to 1.4 MW and just reached 1 MW. The rf-driven multicusp ion source that originates from the Lawrence Berkeley National Laboratory has been delivering ˜38 mA H- beam in the linac at 60 Hz, 0.9 ms. To improve availability, a rf-driven external antenna multicusp ion source with a water-cooled ceramic aluminum nitride (AlN) plasma chamber is developed. Computer modeling and simulations have been made to analyze and optimize the rf performance of the new ion source. Operational statistics and test runs with up to 56 mA medium energy beam transport beam current identify the 2 MHz rf system as a limiting factor in the system availability and beam production. Plasma ignition system is under development by using a separate 13 MHz system. To improve the availability of the rf power system with easier maintenance, we tested a 70 kV isolation transformer for the 80 kW, 6% duty cycle 2 MHz amplifier to power the ion source from a grounded solid-state amplifier.

  2. Nondestructive analysis of the natural uranium mass through the measurement of delayed neutrons using the technique of pulsed neutron source

    International Nuclear Information System (INIS)

    This work presents results of non destructive mass analysis of natural uranium by the pulsed source technique. Fissioning is produced by irradiating the test sample with pulses of 14 MeV neutrons and the uranium mass is calculated on a relative scale from the measured emission of delayed neutrons. Individual measurements were normalised against the integral counts of a scintillation detector measuring the 14 MeV neutron intensity. Delayed neutrons were measured using a specially constructed slab detector operated in anti synchronism with the fast pulsed source. The 14 MeV neutrons were produced via the T(d,n) 4He reaction using a 400 kV Van de Graaff accelerated operated at 200 kV in the pulsed source mode. Three types of sample were analysed, namely: discs of metallic uranium, pellets of sintered uranium oxide and plates of uranium aluminium alloy sandwiched between aluminium. These plates simulated those of Material Testing Reactor fuel elements. Results of measurements were reproducible to within an overall error in the range 1.6 to 3.9%; the specific error depending on the shape, size and mass of the sample. (author)

  3. Design of intense neutron source for fusion material study and the role of universities

    International Nuclear Information System (INIS)

    Need and requirement for the intense neutron source for fusion materials study have been discussed for many years. Recently, international climate has been becoming gradually maturing to consider this problem more seriously because of the recognition of crucial importance of solving materials problems for fusion energy development. The present symposium was designed to discuss the problems associated with the intense neutron source for material irradiation studies which will have a potential for the National Institute for Fusion Science to become one of the important future research areas. The symposium comprises five sessions; first, the role of materials research in fusion development strategies was discussed followed by a brief summary of current IFMIF (International Fusion Materials Irradiation Facility) activity. Despite the pressing need for intense fusion neutron source, currently available neutron sources are reactor or accelerator based sources of which FFTF and LASREF were discussed. Then, various concepts of intense neutron source candidates were presented including ESNIT, which are currently under design by JAERI. In the fourth session, discussions were made on the study of materials with the intense neutron source from the viewpoint of materials scientists and engineers as the user of the facility. This is followed by discussions on the role of universities from the two stand points, namely, fusion irradiation studies and fusion materials development. Finally summary discussions were made by the participants, indicating important role fundamental studies in universities for the full utilization of irradiation data and the need of pure 14 MeV neutron source for fundamental studies together with the intense surrogate neutron sources. (author)

  4. Assessment of the neutron cross section database for mercury for the ORNL spallation source

    Energy Technology Data Exchange (ETDEWEB)

    Leal, L.C.; Spencer, R.R.; Ingersoll, D.T.; Gabriel, T.A. [Oak Ridge National Lab., TN (United States)

    1996-06-01

    Neutron source generation based on a high energy particle accelerator has been considered as an alternative to the canceled Advanced Neutron Source project at Oak Ridge National Laboratory. The proposed technique consists of a spallation neutron source in which neutrons are produced via the interaction of high-energy charged particles in a heavy metal target. Preliminary studies indicate that liquid mercury bombarded with GeV protons provides an excellent neutron source. Accordingly, a survey has been made of the available neutron cross-section data. Since it is expected that spectral modifiers, specifically moderators, will also be incorporated into the source design, the survey included thermal energy, resonance region, and high energy data. It was found that data of individual isotopes were almost non-existent and that the only evaluation found for the natural element had regions of missing data or discrepant data. Therefore, it appears that to achieve the desired degree of accuracy in the spallation source design it is necessary to re-evaluate the mercury database including making new measurements. During the presentation the currently available data will be presented and experiments proposed which can lead to design quality cross sections.

  5. International seminar on structural investigations on pulsed neutron sources. Proceedings

    International Nuclear Information System (INIS)

    The proceedings of the International seminar on structural investigations using pulsed neutron sources are presented. The seminar is dedicated to the memory of Dr. Yu.M. Ostanevich, a world acknowledged physicist. The problems of structural analysis using pulsed neutron source at the IBR-2 reactor are discussed

  6. Production, distribution and applications of californium-252 neutron sources

    International Nuclear Information System (INIS)

    The radioisotope 252Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-yr half-life. A source the size of a person's little finger can emit up to 1011 neutrons s-1. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement and minerals, as well as for detection and identification of explosives, land mines and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 yr of experience and by US Bureau of Mines tests of source survivability during explosions. The production and distribution center for the US Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells 252Cf to commercial reencapsulators domestically and internationally. Sealed 252Cf sources are also available for loan to agencies and subcontractors of the US government and to universities for educational, research and medical applications. The REDC has established the Californium User Facility (CUF) for Neutron Science to make its large inventory of 252Cf sources available to researchers for irradiations inside uncontaminated hot cells. Experiments at the CUF include a land mine detection system, neutron damage testing of solid-state detectors, irradiation of human cancer cells for boron neutron capture therapy experiments and irradiation of rice to induce genetic mutations

  7. Production, distribution and applications of californium-252 neutron sources.

    Science.gov (United States)

    Martin, R C; Knauer, J B; Balo, P A

    2000-01-01

    The radioisotope 252Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-yr half-life. A source the size of a person's little finger can emit up to 10(11) neutrons s(-1). Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement and minerals, as well as for detection and identification of explosives, land mines and unexploded military ordinance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 yr of experience and by US Bureau of Mines tests of source survivability during explosions. The production and distribution center for the US Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells 252Cf to commercial reencapsulators domestically and internationally. Sealed 252Cf sources are also available for loan to agencies and subcontractors of the US government and to universities for educational, research and medical applications. The REDC has established the Californium User Facility (CUF) for Neutron Science to make its large inventory of 252Cf sources available to researchers for irradiations inside uncontaminated hot cells. Experiments at the CUF include a land mine detection system, neutron damage testing of solid-state detectors, irradiation of human cancer cells for boron neutron capture therapy experiments and irradiation of rice to induce genetic mutations. PMID:11003521

  8. Neutronic study of spherical cold-neutron sources composed of liquid hydrogen and liquid deuterium

    CERN Document Server

    Matsuo, Y; Nagaya, Y

    2003-01-01

    Using the cross-section model for neutron scattering in liquid H sub 2 and D sub 2 , a neutron transport analysis is performed for spherical cold-neutron sources composed of either para H sub 2 , normal H sub 2 or normal D sub 2. A special effort is made to generate a set of energy-averaged cross-sections (80 group constants between 0.1 mu eV and 10 eV) for liquid H sub 2 and D sub 2 at melting and boiling points. A number of conclusions on the spherical cold-neutron source configurations are drawn. It is especially shown that the highest cold-neutron flux is obtainable from the normal D sub 2 source with a radius of about 50 cm, while the normal- and para-H sub 2 sources with radii around 3-4 cm produce maximum cold-neutron fluxes at the center.

  9. Separation of beam and electrons in the spallation neutron source H- ion source

    International Nuclear Information System (INIS)

    The Spallation Neutron Source (SNS) requires an ion source producing an H- beam with a peak current of 35 mA at a 6.2% duty factor. For the design of this ion source, extracted electrons must be transported and dumped without adversely affecting the H- beam optics. Two issues are considered: (1) electron containment transport and controlled removal; and (2) first-order H- beam steering. For electron containment, various magnetic, geometric and electrode biasing configurations are analyzed. A kinetic description for the negative ions and electrons is employed with self-consistent fields obtained from a steady-state solution to Poisson's equation. Guiding center electron trajectories are used when the gyroradius is sufficiently small. The magnetic fields used to control the transport of the electrons and the asymmetric sheath produced by the gyrating electrons steer the ion beam. Scenarios for correcting this steering by split acceleration and focusing electrodes will be considered in some detail

  10. Nondiffractive applications of neutrons at the spallation source SINQ

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, E. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-11-01

    The paper delivers an overview about experiments with neutrons from the spallation source SINQ which are not especially devoted to neutron scattering. A total of six experimental facilities are under construction using thermal as well as cold neutrons. Starting with some general considerations about the interaction of neutrons with matter, the principles, boundary conditions and the experimental set up of these experiments are described briefly. Some more details are given for the neutron radiography facility NEUTRA as the author`s special interest and research field. (author) 7 figs., 2 tabs., 9 refs.

  11. Evaluation of area monitor response for neutrons in radiation field generated by a 15 MV clinic accelerator; Avaliacao da resposta dos monitores de area para neutrons em campo de radiacao gerado por um acelerador clinico de 15 MV

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, Ana Paula

    2011-07-01

    The clinical importance and usage of linear accelerators in cancer treatment increased significantly in the last years. Coupled with this growth came the concern about the use of accelerators with energies over to 10 MeV which produce therapeutic beam contaminated with neutrons generated when high-energy photons interact with high-atomic-number materials such as tungsten and lead present in the accelerator itself. At these facilities, measurements of the ambient dose equivalent for neutrons present difficulties owing to the existence of a mixed radiation field and possible electromagnetic interference near the accelerator. The Neutron Laboratory of the IRD - Brazilian Institute for Radioprotection and Dosimetry, aiming to evaluate the survey meters performance at these facilities, initiated studies of instrumentation response in the presence of different neutron spectra. Neutrons sources with average energies ranging from 0.55 to 4.2 MeV, four different survey meters and one ionization chamber to obtain the ratio between the dose due to neutrons and gamma radiation were used in this work. The evaluation of these measurements, performed in a 15 MV linear accelerator room is presented. This work presents results that demonstrate the complexity and care needed to make neutrons measurements in radiotherapy treatment rooms containing high energy clinical accelerators. (author)

  12. The European scene regarding spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, G.S. [Paul Scherrer Institut, Villigen (Austria)

    1996-06-01

    In Europe, a short pulse spallation neutron source, ISIS, has been operating for over 10 years, working its way up to a beam power level of 200 kW. A continuous source, SINQ, designed for a beam power of up to 1 MW, is scheduled to start operating at the end of 1996, and a detailed feasibility study has been completed for a 410 kW short pulse source, AUSTRON. Each of these sources seems to have settled for a target concept which is at or near the limits of its feasibility: The ISIS depleted uranium plate targets, heavy water cooled and Zircaloy clad, have so far not shown satisfactory service time and operation is likely to continue with a Ta-plate target, which, in the past has been used successfully for the equivalent of one full-beam-year before it was taken out of service due to degrading thermal properties. SINQ will initially use a rod target, made of Zircaloy only, but plans exist to move on to clad lead rods as quickly as possible. Apart from the not yet explored effect of hydrogen and helium production, there are also concerns about the generation of 7-Be in the cooling water from the spallation of oxygen, which might result in undesirably high radioactivity in the cooling plant room. A Liquid metal target, also under investigation for SINQ, would not only reduce this problem to a level of about 10 %, but would also minimize the risk of radiolytic corrosion in the beam interaction zone. Base on similar arguments, AUSTRON has been designed for edge cooled targets, but thermal and stress analyses show, that this concept is not feasible at higher power levels.

  13. Fuel cycle for a fusion neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Ananyev, S. S., E-mail: Ananyev-SS@nrcki.ru; Spitsyn, A. V., E-mail: spitsyn-av@nrcki.ru; Kuteev, B. V., E-mail: Kuteev-BV@nrcki.ru [National Research Center Kurchatov Institute (Russian Federation)

    2015-12-15

    The concept of a tokamak-based stationary fusion neutron source (FNS) for scientific research (neutron diffraction, etc.), tests of structural materials for future fusion reactors, nuclear waste transmutation, fission reactor fuel production, and control of subcritical nuclear systems (fusion–fission hybrid reactor) is being developed in Russia. The fuel cycle system is one of the most important systems of FNS that provides circulation and reprocessing of the deuterium–tritium fuel mixture in all fusion reactor systems: the vacuum chamber, neutral injection system, cryogenic pumps, tritium purification system, separation system, storage system, and tritium-breeding blanket. The existing technologies need to be significantly upgraded since the engineering solutions adopted in the ITER project can be only partially used in the FNS (considering the capacity factor higher than 0.3, tritium flow up to 200 m{sup 3}Pa/s, and temperature of reactor elements up to 650°C). The deuterium–tritium fuel cycle of the stationary FNS is considered. The TC-FNS computer code developed for estimating the tritium distribution in the systems of FNS is described. The code calculates tritium flows and inventory in tokamak systems (vacuum chamber, cryogenic pumps, neutral injection system, fuel mixture purification system, isotope separation system, tritium storage system) and takes into account tritium loss in the fuel cycle due to thermonuclear burnup and β decay. For the two facility versions considered, FNS-ST and DEMO-FNS, the amount of fuel mixture needed for uninterrupted operation of all fuel cycle systems is 0.9 and 1.4 kg, consequently, and the tritium consumption is 0.3 and 1.8 kg per year, including 35 and 55 g/yr, respectively, due to tritium decay.

  14. Fuel cycle for a fusion neutron source

    Science.gov (United States)

    Ananyev, S. S.; Spitsyn, A. V.; Kuteev, B. V.

    2015-12-01

    The concept of a tokamak-based stationary fusion neutron source (FNS) for scientific research (neutron diffraction, etc.), tests of structural materials for future fusion reactors, nuclear waste transmutation, fission reactor fuel production, and control of subcritical nuclear systems (fusion-fission hybrid reactor) is being developed in Russia. The fuel cycle system is one of the most important systems of FNS that provides circulation and reprocessing of the deuterium-tritium fuel mixture in all fusion reactor systems: the vacuum chamber, neutral injection system, cryogenic pumps, tritium purification system, separation system, storage system, and tritium-breeding blanket. The existing technologies need to be significantly upgraded since the engineering solutions adopted in the ITER project can be only partially used in the FNS (considering the capacity factor higher than 0.3, tritium flow up to 200 m3Pa/s, and temperature of reactor elements up to 650°C). The deuterium-tritium fuel cycle of the stationary FNS is considered. The TC-FNS computer code developed for estimating the tritium distribution in the systems of FNS is described. The code calculates tritium flows and inventory in tokamak systems (vacuum chamber, cryogenic pumps, neutral injection system, fuel mixture purification system, isotope separation system, tritium storage system) and takes into account tritium loss in the fuel cycle due to thermonuclear burnup and β decay. For the two facility versions considered, FNS-ST and DEMO-FNS, the amount of fuel mixture needed for uninterrupted operation of all fuel cycle systems is 0.9 and 1.4 kg, consequently, and the tritium consumption is 0.3 and 1.8 kg per year, including 35 and 55 g/yr, respectively, due to tritium decay.

  15. Neutron energy spectrum adjustment using deposited metal films on Teflon in the miniature neutron source reactor.

    Science.gov (United States)

    Nassan, L; Abdallah, B; Omar, H; Sarheel, A; Alsomel, N; Ghazi, N

    2016-01-01

    The focus of this article was on the experimental estimation of the neutron energy spectrum in the inner irradiation site of the miniature neutron source reactor (MNSR), using, for the first time, a selected set of deposited metal films on Teflon (DMFTs) neutron detectors. Gold, copper, zinc, titanium, aluminum, nickel, silver, and chromium were selected because of the dependence of their neutron cross-sections on neutron energy. Emphasis was placed on the usability of this new type of neutron detectors in the total neutron energy spectrum adjustment. The measured saturation activities per target nucleus values of the DMFTs, and the calculated neutron spectrum in the inner irradiation site using the MCNP-4C code were used as an input for the STAY'SL computer code during the adjustment procedure. The agreement between the numerically calculated and experimentally adjusted spectra results was discussed. PMID:26562448

  16. Optimization of He-II UCN source with spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Mishima, K.; Choi, E.; Yoshimura, M. [Osaka Univ., Ibaraki (Japan). Research Center for Nuclear Physics; Ooi, M.; Kiyanagi, Y. [Hokkaido Univ., Sapporo (Japan); Masuda, Y.; Muto, S. [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan); Tanaka, M. [Kobe Tokiwa Collage, Kobe, Hyogo (Japan)

    2001-03-01

    A spallation neutron source was designed for super thermal UCN production in He-II. The configuration of neutron production target, moderator and He-II bottle was optimized in order to obtain high neutron flux with low {gamma} heating in He-II. In the optimization the advantage of the spallation neutron source is used: The spallation neutron source has high n/{gamma} ratio and freedom in target moderator configuration in comparison with the reactor. As a result, a great improvement in UCN density is expected compared with the present most intense UCN source at the Grenoble reactor. (authors)

  17. Experimental Results on the First Short Pulse Laser Driven Neutron Source Powerful Enough For Applications In Radiography

    Science.gov (United States)

    Guler, Nevzat

    2012-10-01

    Short pulse laser driven neutron source can be a compact and relatively cheap way to produce neutrons with energies in excess of 10 MeV. It is based on short pulse laser driven ions interacting with a converter material to produce neutrons via separation or breakup mechanisms. Previous research on the short pulse laser driven ion acceleration has mainly concentrated on surface acceleration mechanisms, which typically yield isotropic emission of neutrons from the converter. Recent experiments performed with a high contrast laser at TRIDENT facility at LANL demonstrated laser driven ion acceleration mechanism based on the concept of relativistic transparency. This produced an intense beam of high energy (up to 80 MeV) deuterons directed into a Be converter to produce a forward peaked neutron flux with a record yield, on the order of 4.4x10^9 n/sr. The produced neutron beam had a pulse duration less than a nanosecond and an energy range between 2-80 MeV, peaking around 12 MeV. The neutrons in the energy range of 2.5 to 15 MeV were selected by the gated neutron imager to radiograph tungsten blocks of different thicknesses. We will present the results from the two acceleration mechanisms and the first short pulse laser generated neutron radiograph.

  18. Physics data base for the beam plasma neutron source (BPNS)

    Energy Technology Data Exchange (ETDEWEB)

    Coensgen, F.H.; Casper, T.A.; Correll, D.L.; Damm, C.C.; Futch, A.H.; Molvik, A.W.

    1990-10-12

    A 14-MeV deuterium-tritium (D-T) neutron source for accelerated end-of-life testing of fusion reactor materials has been designed on the basis of a linear two-component collisional plasma system. An intense flux (up to 5 {times} 10{sup 18}/m{sup 2}{center dot}s) of 14-MeV neutrons is produced in a fully ionized high-density (n{sub e} {approx equal} 3 {times} 10{sup 21} m{sup {minus}3}) tritium target by transverse injection of 60 MW of neutral beam power. Power deposited in the target is removed by thermal electron conduction to large end chambers, where it is deposited in gaseous plasma collectors. We show in this paper that the major physics issues have now been experimentally demonstrated. These include magnetohydrodynamic (MHD) equilibrium and stability, microstability, startup, fueling, Spitzer electron thermal conductivity, and power deposition in a gaseous plasma collector. However, an integrated system has not been demonstrated. 28 refs., 8 figs., 2 tabs.

  19. 99Mo Production via 100Mo(n,2n)99Mo using accelerator neutrons

    OpenAIRE

    Nagai Yasuki

    2014-01-01

    A new production method of 99Mo using accelerator neutrons via the 100Mo(n,2n)99Mo reaction was proposed. Intense neutrons with a most probable energy of 14 MeV can be produced by bombarding Be or C with 40 MeV deuteron beams. Research and development works of 99Mo produced by neutrons from the 3H(d,n)4He reaction were carried out. High quality 99mTc was obtained by employing a sublimation method. Accelerator neutrons are shown to have a great potential to produce a wide variety of radioisoto...

  20. Virtual Gamma Ray Radiation Sources through Neutron Radiative Capture

    Energy Technology Data Exchange (ETDEWEB)

    Scott Wilde, Raymond Keegan

    2008-07-01

    The countrate response of a gamma spectrometry system from a neutron radiation source behind a plane of moderating material doped with a nuclide of a large radiative neutron capture cross-section exhibits a countrate response analogous to a gamma radiation source at the same position from the detector. Using a planar, surface area of the neutron moderating material exposed to the neutron radiation produces a larger area under the prompt gamma ray peak in the detector than a smaller area of dimensions relative to the active volume of the gamma detection system.

  1. Production, Distribution, and Applications of Californium-252 Neutron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Balo, P.A.; Knauer, J.B.; Martin, R.C.

    1999-10-03

    The radioisotope {sup 252}Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-year half-life. A source the size of a person's little finger can emit up to 10{sup 11} neutrons/s. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement, and minerals, as well as for detection and identification of explosives, laud mines, and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards, and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 years of experience and by U.S. Bureau of Mines tests of source survivability during explosions. The production and distribution center for the U. S Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells The radioisotope {sup 252}Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6- year half-life. A source the size of a person's little finger can emit up to 10 neutrons/s. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement, and minerals, as well as for detection and identification of explosives, laud mines, and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards, and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 years of experience and by U.S. Bureau of Mines tests of source survivability during explosions. The production and distribution center for the U. S Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory(ORNL). DOE sells {sup 252}Cf to commercial

  2. Monte-Carlo simulations of elastically backscattered neutrons from hidden explosives using three different neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    ElAgib, I. [College of Science, King Saud University, P.O. Box 2455 (Saudi Arabia)], E-mail: elagib@ksu.edu.sa; Elsheikh, N. [College of Applied and Industrial Science, University of Juba, Khartoum, P.O. Box 321 (Sudan); AlSewaidan, H. [College of Science, King Saud University, P.O. Box 2455 (Saudi Arabia); Habbani, F. [Faculty of Science, Physics Department, University of Khartoum, Khartoum, P.O. Box 321 (Sudan)

    2009-01-15

    Calculations of elastically backscattered (EBS) neutrons from hidden explosives buried in soil were performed using Monte-Carlo N-particle transport code MCNP5. Three different neutron sources were used in the study. The study re-examines the performance of the neutron backscattering methods in providing identification of hidden explosives through their chemical composition. The EBS neutron energy spectra of fast and slow neutrons of the major constituent elements in soil and an explosive material in form of TNT have shown definite structures that can be used for the identification of a buried landmine.

  3. Fissile mass estimation by pulsed neutron source interrogation

    Energy Technology Data Exchange (ETDEWEB)

    Israelashvili, I., E-mail: israelashvili@gmail.com [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel); Dubi, C.; Ettedgui, H.; Ocherashvili, A. [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel); Pedersen, B. [Nuclear Security Unit, Institute for Transuranium Elements, Joint Research Centre, Via E. Fermi, 2749, 21027 Ispra (Italy); Beck, A. [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel); Roesgen, E.; Crochmore, J.M. [Nuclear Security Unit, Institute for Transuranium Elements, Joint Research Centre, Via E. Fermi, 2749, 21027 Ispra (Italy); Ridnik, T.; Yaar, I. [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel)

    2015-06-11

    Passive methods for detecting correlated neutrons from spontaneous fissions (e.g. multiplicity and SVM) are widely used for fissile mass estimations. These methods can be used for fissile materials that emit a significant amount of fission neutrons (like plutonium). Active interrogation, in which fissions are induced in the tested material by an external continuous source or by a pulsed neutron source, has the potential advantages of fast measurement, alongside independence of the spontaneous fissions of the tested fissile material, thus enabling uranium measurement. Until recently, using the multiplicity method, for uranium mass estimation, was possible only for active interrogation made with continues neutron source. Pulsed active neutron interrogation measurements were analyzed with techniques, e.g. differential die away analysis (DDA), which ignore or implicitly include the multiplicity effect (self-induced fission chains). Recently, both, the multiplicity and the SVM techniques, were theoretically extended for analyzing active fissile mass measurements, made by a pulsed neutron source. In this study the SVM technique for pulsed neutron source is experimentally examined, for the first time. The measurements were conducted at the PUNITA facility of the Joint Research Centre in Ispra, Italy. First promising results, of mass estimation by the SVM technique using a pulsed neutron source, are presented.

  4. Fundamental neutron physics at a 1 MW long pulse spallation neutron source

    International Nuclear Information System (INIS)

    Modern neutron sources and modern neutron science share a common origin in mid twentieth century scientific investigations concerned with the study of the fundamental interactions between elementary particles. Since the time of that common origin, neutron science and the study of elementary particles have evolved into quite disparate disciplines. The neutron became recognized as a powerful tool for the study of condensed matter with modern neutron sources being primarily used (and primarily justified) as tools for condensed matter research. The study of elementary particles has, of course, led to the development of rather different tools and is now dominated by activities carried out at extremely high energies. Notwithstanding this trend, the study of fundamental interactions using neutrons has continued and remains a vigorous activity at many contemporary neutron sources. This research, like neutron scattering research, has benefited enormously by the development of modern high flux neutron facilities. Future sources, particularly high power spallation sources, offer exciting possibilities for the continuation of this program of research

  5. Optimisation of resolution in accelerator-based fast neutron radiography

    CERN Document Server

    Rahmanian, H; Watterson, J I W

    2002-01-01

    In fast neutron radiography, imaging geometry, neutron scattering, the fast neutron scintillator and the position-sensitive detector all influence feature contrast, resolution and the signal-to-noise ratio in the image. The effect of imaging geometry can be explored by using a ray-tracing method. This requires following the path of neutrons through the imaging field, which includes the sample of interest. A relationship between imaging geometry and feature detectability can be developed. Monte Carlo methods can be used to explore the effect of neutron scattering on the results obtained with the ray-tracing technique. Fast neutrons are detected indirectly via neutron-nucleon scattering reactions. Using hydrogen-rich scintillators and relying on the recoil protons to ionise the scintillator material is the most sensitive technique available. The efficiency, geometry and composition of these scintillators influence the detectability of features in fast neutron radiography. These scintillator properties have a di...

  6. Simulation study of accelerator based quasi-mono-energetic epithermal neutron beams for BNCT.

    Science.gov (United States)

    Adib, M; Habib, N; Bashter, I I; El-Mesiry, M S; Mansy, M S

    2016-01-01

    Filtered neutron techniques were applied to produce quasi-mono-energetic neutron beams in the energy range of 1.5-7.5 keV at the accelerator port using the generated neutron spectrum from a Li (p, n) Be reaction. A simulation study was performed to characterize the filter components and transmitted beam lines. The feature of the filtered beams is detailed in terms of optimal thickness of the primary and additive components. A computer code named "QMNB-AS" was developed to carry out the required calculations. The filtered neutron beams had high purity and intensity with low contamination from the accompanying thermal, fast neutrons and γ-rays.

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

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J.H. (ed.) (Oak Ridge National Lab., TN (United States)); Selby, D.L.; Harrington, R.M. (Oak Ridge National Lab., TN (United States)); Thompson, P.B. (Martin Marietta Energy Systems, Inc., (United States). Engineering Division)

    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 C Research and Development; Design; and Safety.

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

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J.H. [ed.] [Oak Ridge National Lab., TN (United States); Selby, D.L.; Harrington, R.M. [Oak Ridge National Lab., TN (United States); Thompson, P.B. [Martin Marietta Energy Systems, Inc., (United States). Engineering Division

    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 & C Research and Development; Design; and Safety.

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas, Zac. (Mexico); Martinez O, S. A., E-mail: fermineutron@yahoo.com [Universidad Pedagogica y Tecnologica de Colombia, Grupo de Fisica Nuclear Aplicada y Simulacion, Av. Central del Norte 39-115, 150003 Tunja, Boyaca (Colombia)

    2015-10-15

    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 {sup 24}NaBe, {sup 24}NaD{sub 2}O, {sup 116}InBe, {sup 140}LaBe, {sup 238}PuLi, {sup 239}PuBe, {sup 241}AmB, {sup 241}AmBe, {sup 241}AmF, {sup 241}AmLi, {sup 242}CmBe, {sup 210}PoBe, {sup 226}RaBe, {sup 252}Cf and {sup 252}Cf/D{sub 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)

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

    International Nuclear Information System (INIS)

    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 24NaBe, 24NaD2O, 116InBe, 140LaBe, 238PuLi, 239PuBe, 241AmB, 241AmBe, 241AmF, 241AmLi, 242CmBe, 210PoBe, 226RaBe, 252Cf and 252Cf/D2O 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)

  12. Rietveld refinement with time-of-flight powder diffraction data from pulsed neutron sources

    International Nuclear Information System (INIS)

    The recent development of accelerator-based pulsed neutron sources has led to the widespread use of the time-of-flight technique for neutron powder diffraction. The properties of the pulsed source make possible unusually high resolution over a wide range of d spacings, high count rates, and the ability to collect complete data at fixed scattering angles. The peak shape and other instrument characteristics can be accurately modelled, which make Rietveld refinement possible for complex structures. In this paper we briefly review the development of the Rietveld method for time-of-flight diffraction data from pulsed neutron sources and discuss the latest developments in high resolution instrumentation and advanced Rietveld analysis methods. 50 refs., 12 figs., 14 tabs

  13. Characterization of the radiation background at the Spallation Neutron Source

    Science.gov (United States)

    DiJulio, Douglas D.; Cherkashyna, Nataliia; Scherzinger, Julius; Khaplanov, Anton; Pfeiffer, Dorothea; Cooper-Jensen, Carsten P.; Fissum, Kevin G.; Kanaki, Kalliopi; Kirstein, Oliver; Ehlers, Georg; Gallmeier, Franz X.; Hornbach, Donald E.; Iverson, Erik B.; Newby, Robert J.; Hall-Wilton, Richard J.; Bentley, Phillip M.

    2016-09-01

    We present a survey of the radiation background at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, TN, USA during routine daily operation. A broad range of detectors was used to characterize primarily the neutron and photon fields throughout the facility. These include a WENDI-2 extended range dosimeter, a thermoscientific NRD, an Arktis 4He detector, and a standard NaI photon detector. The information gathered from the detectors was used to map out the neutron dose rates throughout the facility and also the neutron dose rate and flux profiles of several different beamlines. The survey provides detailed information useful for developing future shielding concepts at spallation neutron sources, such as the European Spallation Source (ESS), currently under construction in Lund, Sweden.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-01

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

  15. Multipurpose intense 14 MeV neutron source at Bratislava: Design study

    International Nuclear Information System (INIS)

    The present state of design of the multipurpose intense 14 MeV neutron source based on a D+ ion beam and a metal tritide target is reported. It is essentially a 300 keV electrostatic air insulated accelerator capable to accelerate a deuterium ion beam up to 10 mA. With such a beam and a beam spot of 1 cm2, a neutron yield typically 1012 n/s and a useful target lifetime of around 10 h are expected. Various users requirements are met by means of three beam lines: an intense, low current dc and a low current fast pulsed. The key components of the intense source section are the rotating target and the ion source. The rotating target is proposed, with respect of the heat dissipation and the removal of 3 kW/cm2, in continuous operation. A rotation speed up to 1100 rpm is considered. The ion source should deliver about 0.5 kW of extracted D+ ion beam power. A duoplasmatron source with an electrostatic beam focusing system has been selected. Low current sections of the neutron source may operate with a high frequency ion source as well. The dc section for maximum yields around 1010 n/s is designed with special regard to beam monitoring. The fast pulsed section should produce up to 1 ns compressible pulsed D+ ion beam on a target spot with 5 MHz repetition rate. The report includes information about other components of the neutron source as a high voltage power supply, a vacuum system, beam transport, a diagnostic and control system and basic information about neutron source cells and radiation protection. (author)

  16. Laser Plasma Particle Accelerators: Large Fields for Smaller Facility Sources

    Energy Technology Data Exchange (ETDEWEB)

    Geddes, Cameron G.R.; Cormier-Michel, Estelle; Esarey, Eric H.; Schroeder, Carl B.; Vay, Jean-Luc; Leemans, Wim P.; Bruhwiler, David L.; Cary, John R.; Cowan, Ben; Durant, Marc; Hamill, Paul; Messmer, Peter; Mullowney, Paul; Nieter, Chet; Paul, Kevin; Shasharina, Svetlana; Veitzer, Seth; Weber, Gunther; Rubel, Oliver; Ushizima, Daniela; Bethel, Wes; Wu, John

    2009-03-20

    Compared to conventional particle accelerators, plasmas can sustain accelerating fields that are thousands of times higher. To exploit this ability, massively parallel SciDAC particle simulations provide physical insight into the development of next-generation accelerators that use laser-driven plasma waves. These plasma-based accelerators offer a path to more compact, ultra-fast particle and radiation sources for probing the subatomic world, for studying new materials and new technologies, and for medical applications.

  17. Tagging fast neutrons from an (241)Am/(9)Be source.

    Science.gov (United States)

    Scherzinger, J; Annand, J R M; Davatz, G; Fissum, K G; Gendotti, U; Hall-Wilton, R; Håkansson, E; Jebali, R; Kanaki, K; Lundin, M; Nilsson, B; Rosborge, A; Svensson, H

    2015-04-01

    Shielding, coincidence, and time-of-flight measurement techniques are employed to tag fast neutrons emitted from an (241)Am/(9)Be source resulting in a continuous polychromatic energy-tagged beam of neutrons with energies up to 7MeV. The measured energy structure of the beam agrees qualitatively with both previous measurements and theoretical calculations. PMID:25644080

  18. The LICORNE Neutron Source and Measurements of Prompt γ-rays Emitted in Fission

    Science.gov (United States)

    Wilson, J. N.; Lebois, M.; Halipre, P.; Oberstedt, S.; Oberstedt, A.

    The emission of prompt gamma rays is one of the least measured and least well-understood parts of the fission process. Knowledge of prompt fission gamma spectra, mean energies and multiplicities are important for reactor gamma heating and hence linked to reactor safety. At the IPN Orsay we have developed a unique, directional, fast neutron source called LICORNE, intended initially to facilitate prompt fission gamma measurements. The ability of the IPN Orsay tandem accelerator to produce intense beams of 7Li is exploited to produce quasi mono-energetic neutrons between 0.5 - 4 MeV using the p(7Li, 7Be)n inverse reaction. The available fluxes of up to 7×107 neutrons/second/steradian are comparable to existing installations, but with two added advantages: (i) The kinematic focusing produces a natural neutron beam collimation which allows placement of gamma detectors adjacent to the irradiated sample unimpeded by source neutrons. (ii) The background of scattered neutrons in the experimental hall is drastically reduced. The dedicated neutron converter was commissioned in June 2013

  19. Fundamental neutron physics beamline at the spallation neutron source at ORNL

    Energy Technology Data Exchange (ETDEWEB)

    Fomin, N., E-mail: nfomin@utk.edu [University of Tennessee, Knoxville, TN (United States); Greene, G.L. [University of Tennessee, Knoxville, TN (United States); Oak Ridge National Laboratory, Oak Ridge, TN (United States); Allen, R.R.; Cianciolo, V. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Crawford, C. [University of Kentucky, Lexington, KY (United States); Tito, T.M. [Los Alamos National Laboratory, Los Alamos, NM (United States); Huffman, P.R. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); North Carolina State University, Raleigh, NC (United States); Iverson, E.B. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Mahurin, R. [Middle Tennessee State University, Murfreesboro, TN (United States); University of Manitoba, Winnipeg, Manitoba (Canada); Snow, W.M. [Indiana University and Center for the Exploration of Energy and Matter, Bloomington, IN (United States)

    2015-02-11

    We describe the Fundamental Neutron Physics Beamline (FnPB) facility located at the Spallation Neutron Source at Oak Ridge National Laboratory. The FnPB was designed for the conduct of experiments that investigate scientific issues in nuclear physics, particle physics, astrophysics and cosmology using a pulsed slow neutron beam. We present a detailed description of the design philosophy, beamline components, and measured fluxes of the polychromatic and monochromatic beams.

  20. Linear accelerator of All-Union Scientific Research Institute of Experimental Physics for neutron spectrometry

    International Nuclear Information System (INIS)

    The electron linear accelerator intended for neutron spectrometry with a nominal energy of about 55 MeV at currents of 10 A in electron pulse repetition rate of 2400 Hz started in 1985 is described. The special features of linac construction, the measuring complex assembly, the results of spectrum measurements and neutron yield of uranium target are given. The possibilities of accelerator development for increasing the pulse current and pulse length shortening are considered. (orig.)

  1. An End-to-End Test of Neutron Stars as Particle Accelerators

    OpenAIRE

    CARAVEO, PATRIZIA A.

    2005-01-01

    Combining resolved spectroscopy with deep imaging, XMM-Newton is providing new insights on the particle acceleration processes long known to be at work in the magnetospheres of isolated neutron stars. According to a standard theoretical interpretation, in neutron stars' magnetospheres particles are accelerated along the B field lines and, depending on their charge, they can either move outward, to propagate in space, or be funnelled back, towards the star surface. While particles impinging on...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-11-15

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

  3. Use of a Van de Graaff proton accelerator for neutron radiography

    International Nuclear Information System (INIS)

    A neutron radiographic capability has been established at the Pantex ERDA Plant. A 3 MeV Van de Graaff accelerator is being used to make neutron radiographs in order to observe defects of explosives encased in metal containers and ''O'' ring integrity

  4. Use of a Van de Graaff proton accelerator for neutron radiography

    Energy Technology Data Exchange (ETDEWEB)

    Cassidy, J.P.

    1976-12-01

    A neutron radiographic capability has been established at the Pantex ERDA Plant. A 3 MeV Van de Graaff accelerator is being used to make neutron radiographs in order to observe defects of explosives encased in metal containers and ''O'' ring integrity.

  5. Neutron physics and nuclear data measurements with accelerators and research reactors

    International Nuclear Information System (INIS)

    The report contains a collection of lectures devoted to the latest theoretical and experimental developments in the field of fast neutron measurements and in the studies of neutron interactions with nuclei. The possibilities offered by particle accelerators and research reactors for research and technological applications in these fields are pointed out

  6. Response of neutron dosimeters to pulsed neutron fields in high energy electron accelerators at Indus Complex, RRCAT

    International Nuclear Information System (INIS)

    Indus Accelerator Complex (IAC) comprises of two high energy electron accelerators namely Indus-1 SRS (450 MeV) and Indus-2 SRS (2.5 GeV). The radiation environment present is mainly due to Bremsstrahlung Photons and Photo- neutrons produced due to interaction of high-energy electrons with the structural material of accelerators. Since electron beam is pulsed in nature, the radiations produced are also pulsed. The response of commonly used Rem meters is not proper in severely pulsed neutron fields at high dose rates. They tend to underestimate the actual dose. Due to this uncertainty, an attempt was made to study the response of passive integrating type detectors in the pulsed neutron fields found in high energy electron accelerators to get an idea about the ambient neutron field in IAC. The detectors used were CR-39 foils (provided by PMS, RPAD and RSSD, BARC), Bubble Detectors (provided by Defence Laboratory, Jodhpur) and Rem Meter. Neutron dose assessment in both, accessible and inaccessible areas of IAC was carried out using these detectors and the present paper gives the results of preliminary experiments performed. (author)

  7. Compact RF ion source for industrial electrostatic ion accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Hyeok-Jung, E-mail: hjkwon@kaeri.re.kr; Park, Sae-Hoon; Kim, Dae-Il; Cho, Yong-Sub [Korea Multi-purpose Accelerator Complex, Korea Atomic Energy Research Institute, Gyeongsangbukdo 38180 (Korea, Republic of)

    2016-02-15

    Korea Multi-purpose Accelerator Complex is developing a single-ended electrostatic ion accelerator to irradiate gaseous ions, such as hydrogen and nitrogen, on materials for industrial applications. ELV type high voltage power supply has been selected. Because of the limited space, electrical power, and robust operation, a 200 MHz RF ion source has been developed. In this paper, the accelerator system, test stand of the ion source, and its test results are described.

  8. Advanced Neutron Source radiological design criteria

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, J.L.

    1995-08-01

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

  9. Final environmental impact statement, construction and operation of the Spallation Neutron Source. Volume 1

    International Nuclear Information System (INIS)

    DOE proposes to construct and operate a state-of-the-art, short-pulsed, spallation neutron source comprised of an ion source, a linear accelerator, a proton accumulator ring, and an experiment building containing a liquid mercury target and a suite of neutron scattering instrumentation. The proposed Spallation neutron Source would be designed to operate at a proton beam power of 1 megawatt. The design would accommodate future upgrades to a peak operating power of 4 megawatts. These upgrades may include construction of a second proton accumulator ring and a second target. This document analyzes the potential environmental impacts from the proposed action and the alternatives. The analysis assumes a facility operating at a power of 1 MW and 4 MW over the life of the facility. The two primary alternatives analyzed in this FEIS are: the proposed action (to proceed with building the Spallation Neutron Source) and the No-Action Alternative. The No-Action Alternative describes the expected condition of the environment if no action were taken. Four siting alternatives for the Spallation Neutron Source are evaluated: Oak Ridge National Laboratory, Oak Ridge, TN, (preferred alternative); Argonne National Laboratory, Argonne, IL; Brookhaven National Laboratory, Upton, NY; and Los Alamos National Laboratory, Los Alamos, NM

  10. Final environmental impact statement, construction and operation of the Spallation Neutron Source Facility. Summary

    International Nuclear Information System (INIS)

    DOE proposes to construct and operate a state-of-the-art, short-pulsed, spallation neutron source comprised of an ion source, a linear accelerator, a proton accumulator ring, and an experiment building containing a liquid mercury target and a suite of neutron scattering instrumentation. The proposed Spallation Neutron Source would be designed to operate at a proton beam power of 1 megawatt. The design would accommodate future upgrades to a peak operating power of 4 megawatts. These upgrades may include construction of a second proton accumulator ring and a second target. This document analyzes the potential environmental impacts from the proposed action and the alternatives. The analysis assumes a facility operating at a power of 1 MW and 4 MW over the life of the facility. The two primary alternatives analyzed in this FEIS are: the proposed action (to proceed with building the Spallation Neutron Source) and the No-Action Alternative. The No-Action Alternative describes the expected condition of the environment if no action were taken. Four siting alternatives for the Spallation Neutron Source are evaluated: Oak Ridge National Laboratory, Oak Ridge, TN, (preferred alternative); Argonne National Laboratory, Argonne, IL; Brookhaven National Laboratory, Upton, NY; and Los Alamos National Laboratory, Los Alamos, NM

  11. A clean, bright, and versatile source of neutron decay products

    Science.gov (United States)

    Dubbers, D.; Abele, H.; Baeßler, S.; Märkisch, B.; Schumann, M.; Soldner, T.; Zimmer, O.

    2008-11-01

    We present a case study on a new type of beam station for the measurement of angular correlations in the β-decay of free neutrons. This beam station, called proton and electron radiation channel (PERC), is a cold-neutron guide that delivers at its open end, instead of neutrons, a beam of electrons and protons from neutron decays that take place far inside the guide. These charged neutron-decay products are magnetically guided to the end of the neutron guide, where they are separated from the cold-neutron beam. In this way, a general-purpose source of neutron decay products is obtained which can be operated as a user facility for a variety of different experiments in neutron decay correlation spectroscopy that may be installed at this beam station. The angular distribution of the emitted charged particles depends on the magnetic field configuration and can be chosen freely, according to the need of the experiment being carried out. A gain in phase space density of several orders of magnitude can be achieved with PERC, as compared to existing neutron decay spectrometers. Detailed calculations show that the spectra and angular distributions of the emerging electrons and protons will be distortion- and background-free on the level of 10 -4, more than 10 times better than that achieved today.

  12. Crystal structure determination by powder neutron diffraction at the spallation neutron source, ISIS

    International Nuclear Information System (INIS)

    The paper concerns the determination of crystal structure by powder neutron diffraction at the spallation neutron source, ISIS. The practicability of the technique is illustrated by a study of the crystal structure of ferric arsenate, FeAsO4. (U.K.)

  13. High Brightness Neutron Source for Radiography. Final report

    International Nuclear Information System (INIS)

    This research and development program was designed to improve nondestructive evaluation of large mechanical objects by providing both fast and thermal neutron sources for radiography. Neutron radiography permits inspection inside objects that x-rays cannot penetrate and permits imaging of corrosion and cracks in low-density materials. Discovering of fatigue cracks and corrosion in piping without the necessity of insulation removal is possible. Neutron radiography sources can provide for the nondestructive testing interests of commercial and military aircraft, public utilities and petrochemical organizations. Three neutron prototype neutron generators were designed and fabricated based on original research done at the Lawrence Berkeley National Laboratory (LBNL). The research and development of these generators was successfully continued by LBNL and Adelphi Technology Inc. under this STTR. The original design goals of high neutron yield and generator robustness have been achieved, using new technology developed under this grant. In one prototype generator, the fast neutron yield and brightness was roughly 10 times larger than previously marketed neutron generators using the same deuterium-deuterium reaction. In another generator, we integrate a moderator with a fast neutron source, resulting in a high brightness thermal neutron generator. The moderator acts as both conventional moderator and mechanical and electrical support structure for the generator and effectively mimics a nuclear reactor. In addition to the new prototype generators, an entirely new plasma ion source for neutron production was developed. First developed by LBNL, this source uses a spiral antenna to more efficiently couple the RF radiation into the plasma, reducing the required gas pressure so that the generator head can be completely sealed, permitting the possible use of tritium gas. This also permits the generator to use the deuterium-tritium reaction to produce 14-MeV neutrons with increases

  14. SuperSUN - Superfluid Source of Ultra-cold Neutrons

    International Nuclear Information System (INIS)

    A new source of ultra-cold neutrons (UCN) and its implementation in a white cold neutron beam is proposed. The method involves down-scattering of cold neutrons in superfluid Helium-4 by single- and multi-phonon processes. The source shall provide a UCN density of 104/cm3 within a converter with volume up to 50 litres. A UCN source with these parameters will keep ILL competitive. Fully polarised UCN can be offered to the user by activating a small 5 T coil at one end of the converter. The strategy is currently being developed in a feasibility study within the ESFRI project ILL20/20. The present best choice for the location of such a source at the ILL seems the primary cold neutron beam H172. (authors)

  15. Design of small ECR ion source for neutron generator

    International Nuclear Information System (INIS)

    The principles, structures and characteristics of small ECR (Electron Cyclotron Resonance) ion source used in the neutron generator are introduced. The processes of the design and key technique and innovations are described. (authors)

  16. Optimized sub thermal neutron source to Linac of CAB

    International Nuclear Information System (INIS)

    We present the results of calculations performed with the code M C N P relative to the neutron field behavior within the moderator for the Bariloche-Linac cold neutron source, using polyethylene as pre moderator and solid mesitylene as moderating material at 90 K.The optimum dimensions for a moderator were obtained, with and without a pre moderator, from the point of view of neutron production and time-width of the neutron pulse.Finally, we adopted for our cold neutron source, a slab pre moderator of P L E at room temperature, and a cylindrical moderator of mesitylene at 90 K with a cooler system of stainless steel with windows of Zircaloy-4

  17. Plasma diode as a source of power pulses of fast neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Zavada, N.I.; Tsukerman, V.A.; Volodin, M.D.; Gevorkyan, G.G.; Komarov, P.L.; Lyamin, V.I.; Pilipenko, A.V.

    1981-07-01

    A possibility to obtain power neutron pulses using the GI-3 000 and ORION-1 electrostatic accelerators is studied. Two configurations of electron gap are used in the GI-3 00U accelerator: the system with ''conserved cathode'' and combination of the converted cathode with axial magnetic field. Anode plasma obtained from the thin layer of D/sub 2/O freezed on the anode or plasma from spark ion sources, with elements saturated with deuterium or tritium serves as a ion source. The maximum value of total neutron yield obtained with carbon targets reaches 3x10/sup 9/ at W=25 kJ and 2x1U/sup 10/ neutron per pulse at W=40 kJ and for lithium targets - 2x10/sup 10/ and 1x10/sup 11/ neutron per pulse respectively. A conclusion is made that further increase in neutron yield can be reached by improvement of diode electrode system, realization of the maximum energy store in double forming line (W>=200 kJ), improvement of the target quality and ion beam intensity, increase of electron beam self-isolation or application of crossed electric and magnetic fields in the sistem. The realization of these factors permits to increase the total yield by more than one order.

  18. Data acquisition system for the neutron scattering instruments at the intense pulsed neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, R.K.; Daly, R.T.; Haumann, J.R.; Hitterman, R.L.; Morgan, C.B.; Ostrowski, G.E.; Worlton, T.G.

    1981-01-01

    The Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory is a major new user-oriented facility which is now coming on line for basic research in neutron scattering and neutron radiation damage. This paper describes the data-acquisition system which will handle data acquisition and instrument control for the time-of-flight neutron-scattering instruments at IPNS. This discussion covers the scientific and operational requirements for this system, and the system architecture that was chosen to satisfy these requirements. It also provides an overview of the current system implementation including brief descriptions of the hardware and software which have been developed.

  19. Laser Driven Neutron Sources: Characteristics, Applications and Prospects

    OpenAIRE

    Alvarez Ruiz, Jesus; Fernández-Tobias, J.; Mima, K.; Nakai, S; S. Kar; Kato, Y.; Perlado Martin, Jose Manuel

    2012-01-01

    The basics of laser driven neutron sources, properties and possible applications are discussed. We describe the laser driven nuclear processes which trigger neutron generation, namely, nuclear reactions induced by laser driven ion beam (ion n), thermonuclear fusion by implosion and photo-induced nuclear (gamma n) reactions. Based on their main properties, i.e. point source (< 100 μm) and short durations (< ns), different applications are described, such as radiography, time-resolved spe...

  20. An intense 14 MeV neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Su Tongling; Sun Biehe; Yang Baotai; Piao Yubo; Shui Yongqing; Chen Kefan; Wang Xuezhi; Yang Cheng; Niu Zhanqi; Liu Yanton; Pan Minshen; Hong Zhongti; Chen Qin (Lanzhou Univ., GS (China). Inst. of Nuclear Research)

    1990-02-15

    A 3x10{sup 12} n/s source of 14 MeV neutrons is described in this paper. The neutrons are produced by the T(d,n){sup 4}He reaction under a 30 mA, 300 keV deuteron beam bombarding a water-cooled, rotating titanium-tritide target. The size of the beam spot on the target is 1.8 cm, and at the distance of closest approach to the source a neutron flux of 5x10{sup 11} n/cm{sup 2} s is obtained. (orig.).

  1. Status of the Ultracold neutron source upgrade at LANSCE

    Energy Technology Data Exchange (ETDEWEB)

    Pattie, Robert Wayne Jr. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-10-31

    Several slides show the source and flux of ultracold neutrons produced. In summary, an upgraded UCN source has been designed, and parts are currently being fabricated. Nickel phosphorus-coated guides will improve transport to the experiment hall. The source will be installed in the spring of 2016 and commissioned in the fall of 2016.

  2. 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.

  3. AREAL test facility for advanced accelerator and radiation source concepts

    Science.gov (United States)

    Tsakanov, V. M.; Amatuni, G. A.; Amirkhanyan, Z. G.; Aslyan, L. V.; Avagyan, V. Sh.; Danielyan, V. A.; Davtyan, H. D.; Dekhtiarov, V. S.; Gevorgyan, K. L.; Ghazaryan, N. G.; Grigoryan, B. A.; Grigoryan, A. H.; Hakobyan, L. S.; Haroutiunian, S. G.; Ivanyan, M. I.; Khachatryan, V. G.; Laziev, E. M.; Manukyan, P. S.; Margaryan, I. N.; Markosyan, T. M.; Martirosyan, N. V.; Mehrabyan, Sh. A.; Mkrtchyan, T. H.; Muradyan, L. Kh.; Nikogosyan, G. H.; Petrosyan, V. H.; Sahakyan, V. V.; Sargsyan, A. A.; Simonyan, A. S.; Toneyan, H. A.; Tsakanian, A. V.; Vardanyan, T. L.; Vardanyan, A. S.; Yeremyan, A. S.; Zakaryan, S. V.; Zanyan, G. S.

    2016-09-01

    Advanced Research Electron Accelerator Laboratory (AREAL) is a 50 MeV electron linear accelerator project with a laser driven RF gun being constructed at the CANDLE Synchrotron Research Institute. In addition to applications in life and materials sciences, the project aims as a test facility for advanced accelerator and radiation source concepts. In this paper, the AREAL RF photoinjector performance, the facility design considerations and its highlights in the fields of free electron laser, the study of new high frequency accelerating structures, the beam microbunching and wakefield acceleration concepts are presented.

  4. Using a Tandem Pelletron accelerator to produce a thermal neutron beam for detector testing purposes.

    Science.gov (United States)

    Irazola, L; Praena, J; Fernández, B; Macías, M; Bedogni, R; Terrón, J A; Sánchez-Nieto, B; Arias de Saavedra, F; Porras, I; Sánchez-Doblado, F

    2016-01-01

    Active thermal neutron detectors are used in a wide range of measuring devices in medicine, industry and research. For many applications, the long-term stability of these devices is crucial, so that very well controlled neutron fields are needed to perform calibrations and repeatability tests. A way to achieve such reference neutron fields, relying on a 3 MV Tandem Pelletron accelerator available at the CNA (Seville, Spain), is reported here. This paper shows thermal neutron field production and reproducibility characteristics over few days. PMID:26595777

  5. Nuclear and dosimetric features of an isotopic neutron source

    Science.gov (United States)

    Vega-Carrillo, H. R.; Hernández-Dávila, V. M.; Rivera, T.; Sánchez, A.

    2014-02-01

    A multisphere neutron spectrometer was used to determine the features of a 239PuBe neutron source that is used to operate the ESFM-IPN Subcritical Reactor. To determine the source main features it was located a 100 cm from the spectrometer which was a 6LiI(Eu) scintillator and 2, 3, 5, 8, 10 and 12 in.-diameter polyethylene spheres. Count rates obtained with the spectrometer were unfolded using the NSDUAZ code and neutron spectrum, total fluence, and ambient dose equivalent were determined. A Monte Carlo calculation was carried out to estimate the spectrum and integral features being less than values obtained experimentally due to the presence of 241Pu in the Pu used to fabricate the source. Actual neutron yield and the mass fraction of 241Pu was estimated.

  6. Calibration and monitoring of the GENEPI neutron source for the MUSE IV experiment

    International Nuclear Information System (INIS)

    In order to characterize the neutron source produced by the GENEPI accelerator with the titanium tritium (TiT) target, an irradiation experiment was performed in January 2003 in the SC0 configuration of MASURCA, with all the rods inserted. During the irradiation, the LPSC acquisition system was used to monitor the number of pulses and the recoil particles produced by the reactions induced by the deuteron beam. (authors)

  7. Proton injection and RF capture in the national spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Luccio, A.U.; Beebe-Wang, J.; Maletic, D. [and others

    1997-08-01

    The accelerator system for the 1 to 5 MW National Spallation Neutron Source (NSNS) consists of a linac followed by a 1 GeV proton accumulator ring. Since the ring is a very high current machine, the injection and rf capture of the protons is deeply affected by transverse and longitudinal space charge effects. Results of numerical simulation of the process are presented together with considerations on methods and results of space charge treatment in high intensity proton storage rings.

  8. High-flux white neutron source based on p(35)-Be reactions for activation experiments at NPI

    International Nuclear Information System (INIS)

    The concept of International Fusion Material Irradiation Facility (IFMIF) is based on the d(40)-Li neutron source reaction which produces the white neutron spectrum with mean energy of 14 MeV, energy range with high intensity of neutron beam up to 35 MeV, and weak tail up to 55 MeV. At the Nuclear Physics Institute of the ASCR in Rez near Prague, the source reaction of p+Be was investigated for proton energy of 35 MeV and beam current intensity of 9.2μA. The produced white spectrum with neutron flux up to 1011 cm−2 s−1 was determined by the dosimetry foils activation technique at two sample-to-target distances and validated against the Monte Carlo predictions. The neutron field of these high-flux p(35)-Be white neutron source represents the useful tool for experimental simulation of the spectrum of the IFMIF facility, validating the activation cross-section data in the energy range relevant to the IFMIF, studying the radiation hardness of electronics against the high-energy neutron fields, and various activation experiments. - Highlights: • Development of accelerator-driven neutron sources. • Fast neutron spectrometry. • Multi-foil activation technique. • Nuclear data measurement and validation in the energy range of IFMIF

  9. Neutronic Studies in Support of Accelerator-Driven Systems: The MUSE Experiments in the MASURCA Facility

    International Nuclear Information System (INIS)

    The MUSE program (multiplication with an external source) is in progress at the MASURCA critical facility at the Cadarache Research Center of the Commissariat a l'Energie Atomique in France. The program is dedicated to the physics studies of accelerator-driven systems in support of transmutation studies of minor actinides and long-lived fission products. It began in 1995 with the coupling of a Cf source in MASURCA and was followed by a commercial (d,T) source. In 2001, a specially constructed (d,D)/(d,T) neutron generator (GENEPI) was placed in MASURCA and the MUSE-4 program commenced.We describe the first phases of the MUSE-4 program, with data presented that were obtained up to about the summer of 2002. We present some results from the 'reference' configuration, which can operate at critical. We present traverses of measured fission reaction rates, with comparison to calculations. Also in the reference configuration, we performed activation foil measurements and present these results compared to calculations.Because a major objective of the MUSE program is to test and qualify methods of subcritical reactivity measurement, we have devoted a major portion of our studies to this area. We have used classical methods (rod drop, source multiplication) to attempt to measure the subcritical level. In these early phases we studied core configurations of around keff = 0.995. Deeper subcriticality (keff = 0.96) was achieved by inserting a safety rod.In addition to the methods mentioned above, we have devoted a lot of effort to pulse neutron source, fluctuation (Rossi-α and Feynman-α), and transfer function methods (e.g., cross-power spectral density). We present our preliminary results of all the methods, with some discussion regarding cross comparison

  10. Development of hydrogen gauges with small neutron source

    International Nuclear Information System (INIS)

    A new method has been developed for measuring the thickness of a thin layer of 30-200 μm thick plastic sandwiched with two sheets of steel plates of 0.6-4.2mm in total thickness. To obtain a sufficient sensitivity in the measurement, efficient generations of slowed-down neutrons from the plastic layer of a sample were utilized. For the sake of carrying out this method, two iron blocks as fast neutron reflectors are placed with a small gap on the upper and lower sides of a combination of the 252-Cf neutron source and 3-He proportional counter. Furthermore a thin polyethylene sheet is placed as a neutron source and 3-He proportional counter. Furthermore a thin polyethylene sheet is placed as a neutron moderator in the gap. This sheet plays an important role in generating thermal neutrons efficiently from the plastic to be measured owing to multiple reflection of neutrons, through the sheet and sample in the gap with the aid of iron reflectors. A precision of about 10μm was attained in a 1 minute measurement with a 252-Cf source of 40 MBq. We are developing a few gauges using similar concept in some applications

  11. The measurement of neutron energy response of the thin plastic scintillator using white neutron source

    International Nuclear Information System (INIS)

    At the HI-13 accelerator of CIAE, using D (d, n) break-up reaction,the experiment of neutron energy response of the thin plastic scintillator has been performed. The incident energy of D ions are three points of 9 MeV, 12 MeV, 14 MeV, and the neutron energy is between 0.75 MeV and 17 MeV. The intensity of neutron beam is measured by standard liquid scintillation detector at zero degree. The uncertainties of experimental results are discussed in detail. The experimental neutron response curves of the plastic scintillator show that the calculated energy response is in good agreement with the experimental data. (authors)

  12. Characteristics of a RF-Driven Ion Source for a Neutron Generator Used For Associated Particle Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Ying; Hurley, John P.; Ji, Qing; Kwan, Joe; Leung, Ka-Ngo

    2008-08-08

    We present recent work on a prototype compact neutron generator for associated particle imaging (API). API uses alpha particles that are produced simultaneously with neutrons in the deuterium-tritium (2D(3T,n)4 alpha) fusion reaction to determine the direction of the neutrons upon exiting the reaction. This method determines the spatial position of each neutron interaction and requires the neutrons to be generated from a small spot in order to achieve high spatial resolution. The ion source for API is designed to produce a focused ion beam with a beam spot diameter of 1-mm or less on the target. We use an axial type neutron generator with a predicted neutron yield of 108 n/s for a 50 muA D/T ion beam current accelerated to 80 kV. The generator utilizes a RF planar spiral antenna at 13.56 MHz to create a highly efficient inductively-coupled plasma at the ion source. Experimental results show that beams with an atomic ion fraction of over 80percent can be obtained while utilizing only 100 watts of RF power in the ion source. A single acceleration gap with a secondary electron suppression electrode is used in the tube. Experimental results, such as the current density, atomic ion fraction, electron temperature, and electron density, from ion source testing will be discussed.

  13. The sciences and applications of the Electron LINAC-driven neutron source in Argentina

    Science.gov (United States)

    Granada, J. R.; Mayer, R. E.; Dawidowski, J.; Santisteban, J. R.; Cantargi, F.; Blostein, J. J.; Rodríguez Palomino, L. A.; Tartaglione, A.

    2016-06-01

    The Neutron Physics group at Centro Atómico Bariloche (CNEA, Argentina) has evolved for more than forty five years around a small 25MeV linear electron accelerator. It constitutes our compact accelerator-driven neutron source (CANS), which is dedicated to the use and development of neutronic methods to tackle problems of basic sciences and technological applications. Its historical first commitment has been the determination of the total cross sections of materials as a function of neutron energy by means of transmission experiments for thermal and sub-thermal neutrons. This also allowed testing theoretical models for the generation of scattering kernels and cross sections. Through the years, our interests moved from classic pulsed neutron diffraction, which included the development of high-precision methods for the determination of very low hydrogen content in metals, towards deep inelastic neutron scattering (DINS), a powerful tool for the determination of atomic momentum distribution in condensed matter. More recently non-intrusive techniques aimed at the scanning of large cargo containers have started to be developed with our CANS, testing the capacity and limitations to detect special nuclear material and dangerous substances. Also, the ever-present "bremsstrahlung" radiation has been recognized and tested as a useful complement to instrumental neutron activation, as it permits to detect other nuclear species through high-energy photon activation. The facility is also used for graduate and undergraduate students' experimental work within the frame of Instituto Balseiro Physics and Nuclear Engineering courses of study, and also MSc and PhD theses work.

  14. Electrostatic design and beam transport for a folded tandem electrostatic quadrupole accelerator facility for accelerator-based boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Thatar Vento, V., E-mail: Vladimir.ThatarVento@gmail.com [Gerencia de Investigacion y Aplicaciones, CNEA, Av. Gral. Paz 1499 (1650), San Martin, Buenos Aires (Argentina)] [CONICET, Av. Rivadavia 1917 (1033), Ciudad Autonoma de Buenos Aires (Argentina); Bergueiro, J.; Cartelli, D. [Gerencia de Investigacion y Aplicaciones, CNEA, Av. Gral. Paz 1499 (1650), San Martin, Buenos Aires (Argentina)] [CONICET, Av. Rivadavia 1917 (1033), Ciudad Autonoma de Buenos Aires (Argentina); Valda, A.A. [Gerencia de Investigacion y Aplicaciones, CNEA, Av. Gral. Paz 1499 (1650), San Martin, Buenos Aires (Argentina)] [Escuela de Ciencia y Tecnologia, UNSAM, M. Irigoyen 3100 (1650), San Martin, Buenos Aires (Argentina); Kreiner, A.J. [Gerencia de Investigacion y Aplicaciones, CNEA, Av. Gral. Paz 1499 (1650), San Martin, Buenos Aires (Argentina)] [CONICET, Av. Rivadavia 1917 (1033), Ciudad Autonoma de Buenos Aires (Argentina)] [Escuela de Ciencia y Tecnologia, UNSAM, M. Irigoyen 3100 (1650), San Martin, Buenos Aires (Argentina)

    2011-12-15

    Within the frame of an ongoing project to develop a folded Tandem-Electrostatic-Quadrupole (TESQ) accelerator facility for Accelerator-Based Boron Neutron Capture Therapy (AB-BNCT), we discuss here the electrostatic design of the machine, including the accelerator tubes with electrostatic quadrupoles and the simulations for the transport and acceleration of a high intensity beam.

  15. Beam scraping efficiency in the 5 MW spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, A.J.

    1993-12-01

    Numerical calculations have been performed to evaluate the performance of a simple beam scraping system in the lattice of a rapid cycling (30 Hz) proton accelerator designed to be a high intensity spallation neutron source. The assumption has been made that beam loss will be dominated by rf capture inefficiency at injection (600 MeV kinetic) which is simulated as described below. Comparison is made with a ``sample calculation`` intended to illustrate betatron (beam halo) scraping at full energy which was assumed to be 3 GeV. The parameters of the lattice are those of the design as of April, 1993. The results described here are restricted to a geometry wherein the primary scraper is treated as an aperture in the X (horizontal) coordinate. Evaluation of the efficacy of two dimensional scrapers, or scraping systems which employ magnetic fields remain as topics for further study. The purpose of this study was to determine to what extent beam losses can be confined to a local region of the proposed lattice. The remainder of this note describes the general methodology employed, the rf capture beam loss simulation, and the beam halo growth ``sample calculation``. Section V briefly summarizes the results of this study.

  16. Feasibility of sealed D-T neutron generator as neutron source for liver BNCT and its beam shaping assembly.

    Science.gov (United States)

    Liu, Zheng; Li, Gang; Liu, Linmao

    2014-04-01

    This paper involves the feasibility of boron neutron capture therapy (BNCT) for liver tumor with four sealed neutron generators as neutron source. Two generators are placed on each side of the liver. The high energy of these emitted neutrons should be reduced by designing a beam shaping assembly (BSA) to make them useable for BNCT. However, the neutron flux decreases as neutrons pass through different materials of BSA. Therefore, it is essential to find ways to increase the neutron flux. In this paper, the feasibility of using low enrichment uranium as a neutron multiplier is investigated to increase the number of neutrons emitted from D-T neutron generators. The neutron spectrum related to our system has a proper epithermal flux, and the fast and thermal neutron fluxes comply with the IAEA recommended values.

  17. Neutron leakage measurements from a medical linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Palta, J.R.; Hogstrom, K.R.; Tannanonta, C.

    1984-07-01

    The McCall method has been used to measure neutron leakage from the Mevatron 77, 18- and 15-MV photon beams. Gold foil activation has been used employing a beta counting technique for the 18-MV beam and a gamma counting technique for both the 18- and 15-MV beam. The two counting techniques were used to evaluate their relative merit. The measurements were made at various locations in the patient-treatment plane for different field sizes. The results show that the thermal-neutron dose equivalent contributes only about 1%--2% of the total neutron dose equivalent. At 100 cm, the neutron dose equivalent for the 18-MV beam is approximately six times that of the 15-MV beam, slightly exceeding the 0.1% of the useful beam criteria used by some of the regulatory agencies. In light of the uncertainty in fluence to dose equivalent conversion factors, the increased dose equivalent above 0.1% is insignificant.

  18. Expectation for energy selective neutron source based on the current neutron irradiation study of materials

    International Nuclear Information System (INIS)

    For an effective utilization of superior characteristics of the energy selective high energy neutron source, a consideration was made. Electron irradiation with high voltage electron microscopes (HVEM), D-T fusion neutron irradiation with rotating target neutron source (RTNS-II), and fission neutron irradiation with fission reactors were referred. The expected Energy Selective Neutron Source (ESNS) were compared with different types of irradiation facilities in regard to energy spectrum, flux stability, temperature control, and possibility of in-situ experiments. The excellent performance of HVEM electron irradiation, and of RTNS-II D-T fusion neutron irradiation was exemplified. The possibility of extending these excellent performances to the future ESNS experiment was discussed. Difficulties in the neutron irradiation experiment with fission reactors were exemplified. Shrinkage and growth of these difficulties in the ESNS experiment was discussed. Expected advantage and limitation of the ESNS was evaluated. Finally the positioning of ESNS was made, and the importance of its complementality with other facilities was pointed out. (M.T.)

  19. Plans for an Ultra Cold Neutron source at Los Alamos

    Energy Technology Data Exchange (ETDEWEB)

    Seestrom, S.J.; Bowles, T.J.; Hill, R.; Greene, G.L. [Los Alamos National Lab., NM (United States)

    1996-08-01

    Ultra Cold Neutrons (UCN) can be produced at spallation sources using a variety of techniques. To date the technique used has been to Bragg scatter and Doppler shift cold neutrons into UCN from a moving crystal. This is particularly applicable to short-pulse spallation sources. We are presently constructing a UCN source at LANSCE using method. In addition, large gains in UCN density should be possible using cryogenic UCN sources. Research is under way at Gatchina to demonstrate technical feasibility of be a frozen deuterium source. If successful, a source of this type could be implemented at future spallation source, such as the long pulse source being planned at Los Alamos, with a UCN density that may be two orders of magnitude higher than that presently available at reactors. (author)

  20. Design considerations for neutron activation and neutron source strength monitors for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, C.W. [Los Alamos National Lab., NM (United States); Jassby, D.L.; LeMunyan, G.; Roquemore, A.L. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Walker, C. [ITER Joint Central Team, Garching (Germany)

    1997-12-31

    The International Thermonuclear Experimental Reactor will require highly accurate measurements of fusion power production in time, space, and energy. Spectrometers in the neutron camera could do it all, but experience has taught us that multiple methods with redundancy and complementary uncertainties are needed. Previously, conceptual designs have been presented for time-integrated neutron activation and time-dependent neutron source strength monitors, both of which will be important parts of the integrated suite of neutron diagnostics for this purpose. The primary goals of the neutron activation system are: to maintain a robust relative measure of fusion energy production with stability and wide dynamic range; to enable an accurate absolute calibration of fusion power using neutronic techniques as successfully demonstrated on JET and TFTR; and to provide a flexible system for materials testing. The greatest difficulty is that the irradiation locations need to be close to plasma with a wide field of view. The routing of the pneumatic system is difficult because of minimum radius of curvature requirements and because of the careful need for containment of the tritium and activated air. The neutron source strength system needs to provide real-time source strength vs. time with {approximately}1 ms resolution and wide dynamic range in a robust and reliable manner with the capability to be absolutely calibrated by in-situ neutron sources as done on TFTR, JT-60U, and JET. In this paper a more detailed look at the expected neutron flux field around ITER is folded into a more complete design of the fission chamber system.

  1. Evaluation of energy response of neutron rem monitor applied to high-energy accelerator facilities

    Energy Technology Data Exchange (ETDEWEB)

    Nakane, Yoshihiro; Harada, Yasunori; Sakamoto, Yukio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

    2003-03-01

    A neutron rem monitor was newly developed for applying to the high-intensity proton accelerator facility (J-PARC) that is under construction as a joint project between the Japan Atomic Energy Research Institute and the High Energy Accelerator Research Organization. To measure the dose rate accurately for wide energy range of neutrons from thermal to high-energy region, the neutron rem monitor was fabricated by adding a lead breeder layer to a conventional neutron rem monitor. The energy response of the monitor was evaluated by using neutron transport calculations for the energy range from thermal to 150 MeV. For verifying the results, the response was measured at neutron fields for the energy range from thermal to 65 MeV. The comparisons between the energy response and dose conversion coefficients show that the newly developed neutron rem monitor has a good performance in energy response up to 150 MeV, suggesting that the present study offered prospects of a practical fabrication of the rem monitor applicable to the high intensity proton accelerator facility. (author)

  2. Modern trends in ion source development for low-energy accelerators. Final report of a consultants' meeting

    International Nuclear Information System (INIS)

    The IAEA consultative meeting was held to review the status of ion source development for accelerators having output energies less than 100 MeV (low-energy accelerators). Terms of reference for the meeting were to review the status of ion source development for several different types of low-energy accelerators (Van de Graaff, cyclotron, sealed-tube neutron generator, ion implanter, etc.) and to highlight any recent advances in this field. Individual abstracts were prepared for 5 papers presented at this meeting

  3. Status report on the Low Energy Neutron Source for 2015

    Science.gov (United States)

    Baxter, D. V.; Rinckel, T.

    2016-11-01

    The Low Energy Neutron Source at Indiana University first produced cold neutrons in April of 2005. Ten years after first reaching this milestone, the facility has three instruments in operation on its cold target station, and a second target station is devoted to thermal and fast neutron physics offers capabilities in radiation effects research (single-event effects in electronics) and radiography. Key elements in our success over these last ten years have been the diversity of activities we have been able maintain (which often involves using each of our instruments for multiple different activities), the close relationship we have developed with a number of major sources, and the focus we have had on innovation in neutron instrumentation. In this presentation, we will introduce some of the highlights from our most recent activities, provide an update on some of our technical challenges, and describe some of our ideas for the future.

  4. Research for the concept of Hanaro cold neutron source

    International Nuclear Information System (INIS)

    This report consists of two parts, one is the conceptual design performed on the collaboration work with PNPI Russia and another is review of Hanaro CNS conceptual design report by Technicatome France, both of which are contained at vol. I and vol. II. representatively. In the vol. I, the analysis for the status of technology development, the technical characteristics of CNS is included, and the conceptual design of Hanaro cold neutron source is contained to establish the concept suitable to Hanaro. The cold neutron experimental facilities, first of all, have been selected to propose the future direction of physics concerning properties of the matter at Korea. And neutron guide tubes, the experimental hall and cold neutron source appropriate to these devices have been selected and design has been reviewed in view of securing safety and installing at Hanaro. (author). 38 refs., 49 tabs., 17 figs

  5. Characterization of nuclear sources via two-neutron intensity interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Ghetti, R.; Colonna, N.; Helgesson, J.; De Filippo, E.; Tagliente, G.; Anzalone, A.; Bellini, V.; Carlen, L.; Cavallaro, S.; Celano, L.; D' Erasmo, G.; Di Santo, D.; Fiore, E.M.; Fokin, A.; Geraci, M.; Jakobsson, B.; Kuznetsov, A.; Lanzano, G.; Mahboub, D.; Murin, Yu.; Maartensson, J.; Pagano, A.; Palazzolo, F.; Palomba, M.; Pantaleo, A.; Paticchio, V.; Potenza, R.; Riera, G.; Siwek, A.; Sperduto, M.L.; Sutera, C.; Urrata, M.; Westerberg, L

    1999-11-15

    The neutron energy spectrum and the two-neutron correlation function have been measured for the E/A=45 MeV Ni + Al reaction in order to assess the space-time characteristics of the neutron emitting source. When comparing the data to a statistical model, the kinetic energy spectra, the integrated correlation function as well as the longitudinal correlation function are reproduced by one single source. However, only the inclusion of a short-lived pre-equilibrium component can account for the stronger correlation exhibited by neutron pairs emitted with high total momentum. The correlation function from events defined as peripheral by constraints on the highest charge of the projectile-like fragment does show a significantly weaker correlation than the minimum bias sample.

  6. Multiplying target for a high-intensity spallation neutron source

    International Nuclear Information System (INIS)

    The possible design of an intensive pulsed neutron source for time-of-flight experiments is considered. Its major characteristics are expected to be: peak and average slow neutron flux density on the moderator surface up to 1017 and 1014 N/cm2s respectively, neutron pulse duration about 30 μs and pulse repetition rate 25 pps. This level of performance is achieved due to using a multiplying target driven with the proton beam of the Moscow meson factory. (author) 1 fig., 3 tabs., 9 refs

  7. Comparison of ultracold neutron sources for fundamental physics measurements

    CERN Document Server

    Bison, G; Kirch, K; Lauss, B; Ries, D; Schmidt-Wellenburg, P; Zsigmond, G; Brenner, T; Geltenbort, P; Jenke, T; Zimmer, O; Beck, M; Heil, W; Kahlenberg, J; Karch, J; Ross, K; Eberhardt, K; Geppert, C; Karpuk, S; Reich, T; Siemensen, C; Sobolev, Y; Trautmann, N

    2016-01-01

    Ultracold neutrons (UCNs) are key for precision studies of fundamental parameters of the neutron and in searches for new CP violating processes or exotic interactions beyond the Standard Model of particle physics. The most prominent example is the search for a permanent electric dipole moment of the neutron (nEDM). We have performed an experimental comparison of the leading UCN sources currently operating. We have used a 'standard' UCN storage bottle with a volume of 32 liters, comparable in size to nEDM experiments, which allows us to compare the UCN density available at a given beam port.

  8. A dual neutron/gamma source for the Fissmat Inspection for Nuclear Detection (FIND) system.

    Energy Technology Data Exchange (ETDEWEB)

    Doyle, Barney Lee (Sandia National Laboratories, Albuquerque, NM); King, Michael; Rossi, Paolo (Sandia National Laboratories, Albuquerque, NM); McDaniel, Floyd Del (Sandia National Laboratories, Albuquerque, NM); Morse, Daniel Henry; Antolak, Arlyn J.; Provencio, Paula Polyak (Sandia National Laboratories, Albuquerque, NM); Raber, Thomas N.

    2008-12-01

    Shielded special nuclear material (SNM) is very difficult to detect and new technologies are needed to clear alarms and verify the presence of SNM. High-energy photons and neutrons can be used to actively interrogate for heavily shielded SNM, such as highly enriched uranium (HEU), since neutrons can penetrate gamma-ray shielding and gamma-rays can penetrate neutron shielding. Both source particles then induce unique detectable signals from fission. In this LDRD, we explored a new type of interrogation source that uses low-energy proton- or deuteron-induced nuclear reactions to generate high fluxes of mono-energetic gammas or neutrons. Accelerator-based experiments, computational studies, and prototype source tests were performed to obtain a better understanding of (1) the flux requirements, (2) fission-induced signals, background, and interferences, and (3) operational performance of the source. The results of this research led to the development and testing of an axial-type gamma tube source and the design/construction of a high power coaxial-type gamma generator based on the {sup 11}B(p,{gamma}){sup 12}C nuclear reaction.

  9. Construction and operation of the Spallation Neutron Source: Draft environmental impact statement. Volume 2

    International Nuclear Information System (INIS)

    DOE proposes to construct and operate a state-of-the-art, short-pulsed spallation neutron source comprised of an ion source, a linear accelerator, a proton accumulator ring, and an experiment building containing a liquid mercury target and a suite of neutron scattering instrumentation. The proposed Spallation Neutron Source would be designed to operate at a proton beam power of 1 megawatt. The design would accommodate future upgrades to a peak operating power of 4 megawatts. These upgrades may include construction of a second proton accumulation ring and a second target. Volume 1 of this document analyzes the potential environmental impacts from the proposed action and the alternatives. The analysis assumes a facility operating at a power of 1 MW and 4 MW over the life of the facility. The two primary alternatives analyzed in this EIS are: the proposed action (to proceed with building the Spallation Neutron Source) and the No-Action Alternative. This volume contains the following appendices: (A) SNS accident source terms for EIS input; (B) Reports on the selection of alternative sites for the SNS; (C) Letters of consultation on protected species and cultural resources; (D) Ecological resource survey reports and summaries; (E) Descriptions of ORNL research projects in the Walker Branch Watershed; (F) Atmospheric dispersion and dose calculations for normal and accident conditions; (G) Projected air quality modeling effects at NOAA's Walker Branch Monitoring Tower

  10. Commissioning of the Opal reactor cold neutron source

    International Nuclear Information System (INIS)

    Full text: At OPAL, Australia's first cold neutron facility will form an essential part of the reactor's research programs. Fast neutrons, born in the core of a reactor, interact with a cryogenic material, in this case liquid deuterium, to give them very low energies (10meV). A cold neutron flux of 1.4 10E14n/cm2/s is expected, with a peak in the energy spectrum at 4.2meV. The cold neutron source reached cryogenic conditions for the first time in late 2005. The cold neutron source operates with a sub-cooled liquid Deuterium moderator at 24K. The moderator chamber, which contains the deuterium, has been constructed from AlMg5. The thermosiphon and moderator chamber are cooled by helium gas, in a natural convection thermosiphon loop. The helium refrigeration system utilises the Brayton cycle, and is fully insulated within a high vacuum environment. Despite the proximity of the cold neutron source to the reactor core, it has been considered as effectively separate to the reactor system, due to the design of its special vacuum containment vessel. As OPAL is a multipurpose research reactor, used for beam research as well as radiopharmaceutical production and industrial irradiations, the cold neutron source has been designed with a stand-by mode, to maximise production. The stand-by mode is a warm operating mode using only gaseous deuterium at ambient temperatures (∼ 300K), allowing for continued reactor operations whilst parts of the cold source are unavailable or in maintenance. This is the first time such a stand-by feature has been incorporated into a cold source facility

  11. Neutronics studies of solid targets for spallation neutron source using Monte Carlo simulation

    Institute of Scientific and Technical Information of China (English)

    殷雯; 梁九卿

    2003-01-01

    Neutronics studies for a solid target have been done with Monte Carlo high-energy particle transport code NMTC/JAM,when the proton beam with high kinetic energy bombards the target.The effect of the main parameters of the target on the neutron flux is discussed to optimize the target,which will be used for the concept design of the target of spallation neutron source.A target with its aspect ratio 1.5:1 or 2:1 gives the highest neutron flux.Tungsten is the most acceptable material from the technical and economical points of view.Beryllium as a moderating reflector can increase the neutron flux effectively.

  12. Irradiation facilities at the spallation neutron source SINQ

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, E.; Ledermann, J.; Aebersold, H.; Kuehne, G.; Kohlik, K. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    Four independent experiments for sample irradiation are under construction and in preparation for operational tests at the spallation source SINQ. Three of them are located inside a thermal beam port with end positions inside or near the moderator tank. The other experiment will be established at the end position of a super mirror lined neutron guide for applications with cold neutrons. (author) 3 figs., 1 tab., 6 refs.

  13. Spent-fuel photon and neutron source spectra

    International Nuclear Information System (INIS)

    Computational activities at Oak Ridge National Laboratory have been performed to develop appropriate data and techniques for computing the photon and neutron source spectra of spent fuel. The methods reviewed here include both the determination of spent-fuel composition and the radiation source spectra associated with these isotopic inventories

  14. Implementation and training methodology of subcritical reactors neutronic calculations triggered by external neutron source and applications

    International Nuclear Information System (INIS)

    This works had as goal to investigate calculational methodologies on subcritical source driven reactor, such as Accelerator Driven Subcritical Reactor (ADSR) and Fusion Driven Subcritical Reactor (FDSR). Intense R and D has been done about these subcritical concepts, mainly due to Minor Actinides (MA) and Long Lived Fission Products (LLFP) transmutation possibilities. In this work, particular emphasis has been given to: (1) complement and improve calculation methodology with neutronic transmutation and decay capabilities and implement it computationally, (2) utilization of this methodology in the Coordinated Research Project (CRP) of the International Atomic Energy Agency Analytical and Experimental Benchmark Analysis of ADS and in the Collaborative Work on Use of Low Enriched Uranium in ADS, especially in the reproduction of the experimental results of the Yalina Booster subcritical assembly and study of a subcritical core of IPEN / MB-01 reactor, (3) to compare different nuclear data libraries calculation of integral parameters, such as keff and ksrc, and differential distributions, such as spectrum and flux, and nuclides inventories and (4) apply the develop methodology in a study that may help future choices about dedicated transmutation system. The following tools have been used in this work: MCNP (Monte Carlo N particle transport code), MCB (enhanced version of MCNP that allows burnup calculation) and NJOY to process nuclear data from evaluated nuclear data files. (author)

  15. Method to determine the strength of a neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M.; Chacon R, A.; Mercado, G.A. [UAZ, A.P. 336, 98000 Zacatecas (Mexico); Gallego, E.; Lorente, A. [Depto. Ingenieria Nuclear, Universidad Politecnica de Madrid, (Spain)

    2006-07-01

    The use of a gamma-ray spectrometer with a 3 {phi} x 3 NaI(Tl) detector, with a moderator sphere has been studied in the aim to measure the neutron fluence rate and to determine the source strength. Moderators with a large amount of hydrogen are able to slowdown and thermalize neutrons; once thermalized there is a probability that thermal neutron to be captured by hydrogen producing 2.22 MeV prompt gamma-ray. The pulse-height spectrum collected in a multicharmel analyzer shows a photopeak around 2.22 MeV whose net area is proportional to total neutron fluence rate and to the neutron source strength. The characteristics of this system were determined by a Monte Carlo study using the MCNP 4C code, where a detailed model of the Nal(Tl) was utilized. As moderators 3, 5, and 10 inches-diameter spheres where utilized and the response was calculated for monoenergetic and isotopic neutrons sources. (Author)

  16. Neutron source reconstruction from pinhole imaging at National Ignition Facility

    International Nuclear Information System (INIS)

    The neutron imaging system at the National Ignition Facility (NIF) is an important diagnostic tool for measuring the two-dimensional size and shape of the neutrons produced in the burning deuterium-tritium plasma during the ignition stage of inertial confinement fusion (ICF) implosions at NIF. Since the neutron source is small (∼100 μm) and neutrons are deeply penetrating (>3 cm) in all materials, the apertures used to achieve the desired 10-μm resolution are 20-cm long, single-sided tapers in gold. These apertures, which have triangular cross sections, produce distortions in the image, and the extended nature of the pinhole results in a non-stationary or spatially varying point spread function across the pinhole field of view. In this work, we have used iterative Maximum Likelihood techniques to remove the non-stationary distortions introduced by the aperture to reconstruct the underlying neutron source distributions. We present the detailed algorithms used for these reconstructions, the stopping criteria used and reconstructed sources from data collected at NIF with a discussion of the neutron imaging performance in light of other diagnostics

  17. Neutron fluence in a 18 MeV Electron Accelerator for Therapy

    International Nuclear Information System (INIS)

    An investigation was made on the theoretical fundamentals for the determination of the neutron fluence in a linear electron accelerator for radiotherapy applications and the limit values of leakage neutron radiation established by guidelines and standards in radiation protection for these type of accelerators. This investigation includes the following parts: a) Exhaustive bibliographical review on the topics mentioned above, in order to combine and to update the necessary basic information to facilitate the understanding of this subject; b) Analysis of the accelerator operation and identification of its main components, specially in the accelerator head; c) Study of different types of targets and its materials for the Bremsstrahlung production which is based on the electron initial energy, the thickness of the target, and its angular distribution and energy, which influences in the neutron generation by means of the photonuclear and electro disintegration reactions; d) Analysis of the neutron yield based on the target type and its thickness, the energy of electrons and photons; e) Analysis of the neutron energy spectra generated in the accelerator head, inside and outside the treatment room; f) Study of the dosimetry fundamentals for neutron and photon mixed fields, the dosimeter selection criteria and standards applied for these applications, specially the Panasonic U D-809 thermoluminescent dosemeter and C R-39 nuclear track dosimeter; g) Theoretical calculation of the neutron yield using a simplified geometric model for the accelerator head with spherical cell, which considers the target, primary collimator, flattener filter, movable collimators and the head shielding as the main components for radiation production. The cases with W and Pb shielding for closed movable collimators and an irradiation field of 20 x 20 cm2 were analyzed and, h) Experimental evaluation of the leakage neutron radiation from the patient and head planes, observing that the accelerator

  18. Laser wakefield accelerator based light sources: potential applications and requirements

    Energy Technology Data Exchange (ETDEWEB)

    Albert, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). NIF and Photon Sciences; Thomas, A. G. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Nuclear Engineering and Radiological Sciences; Mangles, S. P.D. [Imperial College, London (United Kingdom). Blackett Lab.; Banerjee, S. [Univ. of Nebraska, Lincoln, NE (United States); Corde, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Flacco, A. [ENSTA, CNRS, Ecole Polytechnique, Palaiseau (France); Litos, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Neely, D. [Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Rutherford Appleton Lab. (RAL). Central Laser Facility; Viera, J. [Univ. of Lisbon (Portugal). GoLP-Inst. de Plasmas e Fusao Nuclear-Lab. Associado; Najmudin, Z. [Imperial College, London (United Kingdom). Blackett Lab.; Bingham, R. [Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Rutherford Appleton Lab. (RAL). Central Laser Facility; Joshi, C. [Univ. of California, Los Angeles, CA (United States). Dept. of Electrical Engineering; Katsouleas, T. [Duke Univ., Durham, NC (United States). Platt School of Engineering

    2015-01-15

    In this article we review the prospects of laser wakefield accelerators as next generation light sources for applications. This work arose as a result of discussions held at the 2013 Laser Plasma Accelerators Workshop. X-ray phase contrast imaging, X-ray absorption spectroscopy, and nuclear resonance fluorescence are highlighted as potential applications for laser-plasma based light sources. We discuss ongoing and future efforts to improve the properties of radiation from plasma betatron emission and Compton scattering using laser wakefield accelerators for these specific applications.

  19. THE COMMISSIONING PLAN FOR THE SPALLATION NEUTRON SOURCE RING AND TRANSPORT LINES.

    Energy Technology Data Exchange (ETDEWEB)

    RAPARIA,D.BLASKIEWICZ,M.LEE,Y.Y.WEI,J.ET AL.

    2004-03-10

    The Spallation Neutron Source (SNS) accelerator systems will provide a 1 GeV, 1.44 MW proton beam to a liquid mercury target for neutron production. In order to satisfy the accelerator systems' portion of the Critical Decision 4 (CD-4) commissioning goal (which marks the completion of the construction phase of the project), a beam pulse with intensity greater than 1 x 10{sup 13} protons must be accumulated in the ring, extracted in a single turn and delivered to the target. A commissioning plan has been formulated for bringing into operation and establishing nominal operating conditions for the various ring and transport line subsystems as well as for establishing beam conditions and parameters which meet the commissioning goal.

  20. Study of characteristics for heavy water photoneutron source in boron neutron capture therapy

    CERN Document Server

    Salehi, Danial; Sardari, Dariush

    2013-01-01

    Bremsstrahlung photon beams produced by medical linear accelerators are currently the most commonly used method of radiation therapy for cancerous tumors. Photons with energies greater than 8-10 MeV potentially generate neutrons through photonuclear interactions in the accelerator's treatment head, patient's body, and treatment room ambient. Electrons impinging on a heavy target generate a cascade shower of bremsstrahlung photons, the energy spectrum of which shows an end point equal to the electron beam energy. By varying the target thickness, an optimum thickness exists for which, at the given electron energy, maximum photon flux is achievable. If a source of high-energy photons i.e. bremsstrahlung, is conveniently directed to a suitable D2O target, a novel approach for production of an acceptable flux of filterable photoneturons for boron neutron capture therapy (BNCT) application is possible. This study consists of two parts. 1. Comparison and assessment of deuterium photonuclear cross section data. 2. Ev...

  1. STUDY ON MODERATIORS OF SMALL—SIZE NEUTRON RADIOGRAPHY INSTALLATIONS WITH NEUTRON TUBE AS SOURCE

    Institute of Scientific and Technical Information of China (English)

    马维超; 吴执中; 等

    1995-01-01

    Calculation of moderator analogues for 14 MeV neutrons as source were made at a IBM/PC AT computer using TAMAKER-ANISN program and 46 groups(25 neutron groups,21 photon groups) UW cross section data.The intensifying effect of lead and natural uranium for moderating 14 MeV neutrons is confirmed.Adopting proper structure of the moderator,the intensifying factor M( times) may be larger than 3.Using lead and naural uranium in sub-critical assemblies (or cell boosters),with 14 Me neutrons as source,with the same dimension as that of abouve,the intensifying effect is also confirmed.With a proper structure of sub-critical assembly,the intensifying factor M may be close to or even larger than(1-k)-1 where k is the effective multiplication factor.

  2. Neutron shielding of the GDT (Novosibirsk) neutron source project: A feasibility study

    International Nuclear Information System (INIS)

    The paper presents results of extensive neutronic studies of the neutron source test facility based on the Novosibirsk gas dynamic trap. The facility is to provide 1018 DT-neutrons/s for material-test studies. The paper examines the protective-shields capacity to ensure survival of GDT vital parts and suggests design modifications when survival is in jeopardy. The numerical studies used the 3D-AMC-VINIA Monte Carlo code with a precise computer representation of the sensitive parts of the facility. Shielding feasibility has been ascertained, and the lifetime of consumable components ensured beyond the recommended values

  3. Water-extended polyester neutron shield for a 252Cf neutron source

    International Nuclear Information System (INIS)

    A Monte Carlo study to determine the shielding features to neutrons of water-extended polyester was carried out. During calculations, 252Cf and shielding were modelled and the neutron spectra as well as the H*(10) were calculated in four sites. The calculation was extended to include a water shielding, the source in vacuum and in air. Besides neutron shielding characteristics, the Kerma in air due to gammas emitted by 252Cf and due to capture γ rays in the shielding were included. (authors)

  4. Enriched vs non-enriched vs non-fissile targets for pulsed spallation neutron sources

    International Nuclear Information System (INIS)

    Numerous options exist among alternatives for target material and design of the neutron producing target in pulsed spallation neutron sources. This report surveys the advantages, disadvantages and limitations of some of the alternatives, including discussions of neutron yields, delayed neutron backgrounds, source pulse widths, source-to-moderator coupling, materials performance, fabrication problems, safeguards and security and hazards questions. (author)

  5. Development of a high-speed camera system for neutron imaging at a pulsed neutron source

    International Nuclear Information System (INIS)

    A neutron energy resolved imaging system with a time-of-flight technique has been newly developed and installed at Japan Proton Accelerator Research Complex (J-PARC) with the aim to investigate more preciously and rapidly a spatial distribution of several elements and crystals in various kinds of materials or substances. A high-speed video camera (CMOS, 1300 k frame/s) equipped system allows to obtain TOF images consecutively resolved into narrow energy ranges with a single pulsed neutrons while conventional CCD camera imaging system could obtain only one TOF image in an arbitral neutron energy region in the pulsed neutron energy region from 0.01 eV to a few keV. Qualities of the images obtained with the system, such as spatial resolution (defined by modulation transfer function, 0.8 line-pairs/mm at En∼0.01 eV), dependence of the brightness on the neutron energy and measurement errors (∼2%) of the system were examined experimentally and evaluated by comparison with those of conventional imaging system. The results obtained in the experiments show that the system can visualize the neutron energy resolved images within a small error even at high speed.

  6. Acceleration of criticality analysis solution convergence by matrix eigenvector for a system with weak neutron interaction

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, Yasushi; Takada, Tomoyuki; Kuroishi, Takeshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kadotani, Hiroyuki [Shizuoka Sangyo Univ., Iwata, Shizuoka (Japan)

    2003-03-01

    In the case of Monte Carlo calculation to obtain a neutron multiplication factor for a system of weak neutron interaction, there might be some problems concerning convergence of the solution. Concerning this difficulty in the computer code calculations, theoretical derivation was made from the general neutron transport equation and consideration was given for acceleration of solution convergence by using the matrix eigenvector in this report. Accordingly, matrix eigenvector calculation scheme was incorporated together with procedure to make acceleration of convergence into the continuous energy Monte Carlo code MCNP. Furthermore, effectiveness of acceleration of solution convergence by matrix eigenvector was ascertained with the results obtained by applying to the two OECD/NEA criticality analysis benchmark problems. (author)

  7. The neutron dose equivalent around high energy medical electron linear accelerators

    OpenAIRE

    Poje Marina; Ivković Ana; Jurković Slaven; Žauhar Gordana; Vuković Branko; Radolić Vanja; Miklavčić Igor; Kaliman Zoran; Planinić Josip; Brkić Hrvoje; Faj Dario

    2014-01-01

    The measurement of neutron dose equivalent was made in four dual energy linear accelerator rooms. Two of the rooms were reconstructed after decommissioning of 60Co units, so the main limitation was the space. The measurements were performed by a nuclear track etched detectors LR-115 associated with the converter (radiator) that consist of 10B and with the active neutron detector Thermo BIOREM FHT 742. The detectors were set at several locations to evaluate ...

  8. Nuclear and dosimetric features of an isotopic neutron source

    International Nuclear Information System (INIS)

    A multisphere neutron spectrometer was used to determine the features of a 239PuBe neutron source that is used to operate the ESFM-IPN Subcritical Reactor. To determine the source main features it was located a 100 cm from the spectrometer which was a 6LiI(Eu) scintillator and 2, 3, 5, 8, 10 and 12 in.-diameter polyethylene spheres. Count rates obtained with the spectrometer were unfolded using the NSDUAZ code and neutron spectrum, total fluence, and ambient dose equivalent were determined. A Monte Carlo calculation was carried out to estimate the spectrum and integral features being less than values obtained experimentally due to the presence of 241Pu in the Pu used to fabricate the source. Actual neutron yield and the mass fraction of 241Pu was estimated. - Highlights: • The neutron spectrum of a 239PuBe was measured. • With the spectrum integral features were determined. • It was estimated 0.23 w/o of 241Pu in the Pu used to make the source

  9. Saturn Neutron Exosphere as Source for Inner and Innermost Radiation Belts

    Science.gov (United States)

    Cooper, John; Lipatov, Alexander; Sittler, Edward; Sturner, Steven

    2011-01-01

    Energetic proton and electron measurements by the ongoing Cassini orbiter mission are expanding our knowledge of the highest energy components of the Saturn magnetosphere in the inner radiation belt region after the initial discoveries of these belts by the Pioneer 11 and Voyager 2 missions. Saturn has a neutron exosphere that extends throughout the magnetosphere from the cosmic ray albedo neutron source at the planetary main rings and atmosphere. The neutrons emitted from these sources at energies respectively above 4 and 8 eV escape the Saturn system, while those at lower energies are gravitationally bound. The neutrons undergo beta decay in average times of about 1000 seconds to provide distributed sources of protons and electrons throughout Saturn's magnetosphere with highest injection rates close to the Saturn and ring sources. The competing radiation belt source for energetic electrons is rapid inward diffusion and acceleration of electrons from the middle magnetosphere and beyond. Minimal losses during diffusive transport across the moon orbits, e.g. of Mimas and Enceladus, and local time asymmetries in electron intensity, suggest that drift resonance effects preferentially boost the diffusion rates of electrons from both sources. Energy dependences of longitudinal gradient-curvature drift speeds relative to the icy moons are likely responsible for hemispheric differences (e.g., Mimas, Tethys) in composition and thermal properties as at least partly produced by radiolytic processes. A continuing mystery is the similar radial profiles of lower energy (neutron decay, but perhaps alternatively from atmospheric albedo, or else all protons from diverse distributed sources are similarly affected by losses at the moon' orbits, e.g. because the proton diffusion rates are extremely low. Enceladus cryovolcanism, and radiolytic processing elsewhere on the icy moon and ring surfaces, are additional sources of protons via ionization and charge exchange from breakup of

  10. Beamed neutron emission driven by laser accelerated light ions

    CERN Document Server

    Kar, S; Ahmed, H; Alejo, A; Robinson, A P L; Cerchez, M; Clarke, R; Doria, D; Dorkings, S; Fernandez, J; Mirfyazi, S R; McKenna, P; Naughton, K; Neely, D; Norreys, P; Peth, C; Powell, H; Ruiz, J A; Swain, J; Willi, O; Borghesi, M

    2015-01-01

    We report on the experimental observation of beam-like neutron emission with peak flux of the order of 10^9 n/sr, from light nuclei reactions in a pitcher-catcher scenario, by employing MeV ions driven by high power laser. The spatial profile of the neutron beam, fully captured for the first time by employing a CR39 nuclear track detector, shows a FWHM divergence angle of 70 degrees, with a peak flux nearly an order of magnitude higher than the isotropic component elsewhere. The observed beamed flux of neutrons is highly favourable for a wide range of applications, and indeed for further transport and moderation to thermal energies. A systematic study employing various combinations of pitcher-catcher materials indicates the dominant reactions being d(p, n+p)^1H and d(d,n)^3He. Albeit insufficient cross-section data are available for modelling, the observed anisotropy in the neutrons' spatial and spectral profiles are most likely related to the directionality and high energy of the projectile ions.

  11. Study of muon-induced neutron production using accelerator muon beam at CERN

    International Nuclear Information System (INIS)

    Cosmogenic muon-induced neutrons are one of the most problematic backgrounds for various underground experiments for rare event searches. In order to accurately understand such backgrounds, experimental data with high-statistics and well-controlled systematics is essential. We performed a test experiment to measure muon-induced neutron production yield and energy spectrum using a high-energy accelerator muon beam at CERN. We successfully observed neutrons from 160 GeV/c muon interaction on lead, and measured kinetic energy distributions for various production angles. Works towards evaluation of absolute neutron production yield is underway. This work also demonstrates that the setup is feasible for a future large-scale experiment for more comprehensive study of muon-induced neutron production

  12. Detection of supernova neutrinos at spallation neutron sources

    Science.gov (United States)

    Huang, Ming-Yang; Guo, Xin-Heng; Young, Bing-Lin

    2016-07-01

    After considering supernova shock effects, Mikheyev-Smirnov-Wolfenstein effects, neutrino collective effects, and Earth matter effects, the detection of supernova neutrinos at the China Spallation Neutron Source is studied and the expected numbers of different flavor supernova neutrinos observed through various reaction channels are calculated with the neutrino energy spectra described by the Fermi-Dirac distribution and the “beta fit” distribution respectively. Furthermore, the numerical calculation method of supernova neutrino detection on Earth is applied to some other spallation neutron sources, and the total expected numbers of supernova neutrinos observed through different reactions channels are given. Supported by National Natural Science Foundation of China (11205185, 11175020, 11275025, 11575023)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-08-15

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

  14. The comparison of four neutron sources for Prompt Gamma Neutron Activation Analysis (PGNAA) in vivo detections of boron

    OpenAIRE

    Fantidis, J. G.; Nicolaou, G. E.; C. Potolias; N. Vordos; Bandekas, D. V.

    2011-01-01

    A Prompt Gamma Ray Neutron Activation Analysis (PGNAA) system, incorporating an isotopic neutron source has been simulated using the MCNPX Monte Carlo code. In order to improve the signal to noise ratio different collimators and a filter were placed between the neutron source and the object. The effect of the positioning of the neutron beam and the detector relative to the object has been studied. In this work the optimisation procedure is demonstrated for boron. Monte Carlo calculations were...

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

    Science.gov (United States)

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

    2016-01-01

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

  16. Planetary method to measure the neutrons spectrum in lineal accelerators of medical use

    International Nuclear Information System (INIS)

    A novel procedure to measure the neutrons spectrum originated in a lineal accelerator of medical use has been developed. The method uses a passive spectrometer of Bonner spheres. The main advantage of the method is that only requires of a single shot of the accelerator. When this is used around a lineal accelerator is necessary to operate it under the same conditions so many times like the spheres that contain the spectrometer, activity that consumes enough time. The developed procedure consists on situating all the spheres of the spectrometer at the same time and to realize the reading making a single shot. With this method the photo neutrons spectrum produced by a lineal accelerator Varian ix of 15 MV to 100 cm of the isocenter was determined, with the spectrum is determined the total flow and the ambient dose equivalent. (Author)

  17. Conceptual design of target station and neutron scattering spectrometers for the Chinese spallation neutron source

    International Nuclear Information System (INIS)

    The authors report the recent progress on the conceptual design of the target station and neutron scattering spectrometers for the Chinese Spallation Neutron Source (CSNS). The CSNS target station will be constructed with three parts: tungsten targets cooled by heavy water, Be/Fe reflectors and Fe/high-density-iron-aggregate-concrete shields. there will be 3 WING moderators: water (300 K), liquid methane (100 K) and liquid hydrogen (20 K), and 18 horizontal neutron channels for neutron scattering spectrometers. The Monte Carlo simulation shows that the optimized ratio of height to width of the target cross-section is ∼1:2.5. With a nuclear power of 100 kW, the pulsed neutron flux is 2.4 x 1016 cm-2·s-1 for a 40 mm x 100 mm x 10 mm x 40 target stack. The emitted heat is about 47 kJ/s, the target temperature is somewhat higher than 90 degree C with a normal cooling efficiency, and the strain should be lower than 0.2 mm. Initially 5 typical spectrometers are chosen to be constructed, including a high intensity powder diffractometer, a high resolution powder diffractometer, a small angle scattering spectrometer, a reflectometer and a direct geometry inelastic neutron scattering spectrometer. These spectrometers can cover more than 80% of the neutron scattering applications. (authors)

  18. Optimizing moderator dimensions for neutron scattering at the spallation neutron source.

    Science.gov (United States)

    Zhao, J K; Robertson, J L; Herwig, Kenneth W; Gallmeier, Franz X; Riemer, Bernard W

    2013-12-01

    In this work, we investigate the effect of neutron moderator dimensions on the performance of neutron scattering instruments at the Spallation Neutron Source (SNS). In a recent study of the planned second target station at the SNS facility, we have found that the dimensions of a moderator play a significant role in determining its surface brightness. A smaller moderator may be significantly brighter over a smaller viewing area. One of the immediate implications of this finding is that for modern neutron scattering instrument designs, moderator dimensions and brightness have to be incorporated as an integrated optimization parameter. Here, we establish a strategy of matching neutron scattering instruments with moderators using analytical and Monte Carlo techniques. In order to simplify our treatment, we group the instruments into two broad categories: those with natural collimation and those that use neutron guide systems. For instruments using natural collimation, the optimal moderator selection depends on the size of the moderator, the sample, and the moderator brightness. The desired beam divergence only plays a role in determining the distance between sample and moderator. For instruments using neutron optical systems, the smallest moderator available that is larger than the entrance dimension of the closest optical element will perform the best (assuming, as is the case here that smaller moderators are brighter).

  19. Fast neutron dosimetry for radioprotection near large accelerators. Application to the proton synchrotron Saturne

    International Nuclear Information System (INIS)

    Methods are described that are used for the measurement of a neutron flux, and of the corresponding energy flux and dose absorbed. The methods are checked experimentally by the use of neutron sources of known energy distribution. The conditions of use of a proportional counter for recoil protons are described. The experimental results obtained with the synchrotron SATURNE at Saclay are described. (author)

  20. High Flux Isotope Reactor cold neutron source reference design concept

    Energy Technology Data Exchange (ETDEWEB)

    Selby, D.L.; Lucas, A.T.; Hyman, C.R. [and others

    1998-05-01

    In February 1995, Oak Ridge National Laboratory`s (ORNL`s) deputy director formed a group to examine the need for upgrades to the High Flux Isotope Reactor (HFIR) system in light of the cancellation of the Advanced neutron Source Project. One of the major findings of this study was that there was an immediate need for the installation of a cold neutron source facility in the HFIR complex. In May 1995, a team was formed to examine the feasibility of retrofitting a liquid hydrogen (LH{sub 2}) cold source facility into an existing HFIR beam tube. The results of this feasibility study indicated that the most practical location for such a cold source was the HB-4 beam tube. This location provides a potential flux environment higher than the Institut Laue-Langevin (ILL) vertical cold source and maximizes the space available for a future cold neutron guide hall expansion. It was determined that this cold neutron beam would be comparable, in cold neutron brightness, to the best facilities in the world, and a decision was made to complete a preconceptual design study with the intention of proceeding with an activity to install a working LH{sub 2} cold source in the HFIR HB-4 beam tube. During the development of the reference design the liquid hydrogen concept was changed to a supercritical hydrogen system for a number of reasons. This report documents the reference supercritical hydrogen design and its performance. The cold source project has been divided into four phases: (1) preconceptual, (2) conceptual design and testing, (3) detailed design and procurement, and (4) installation and operation. This report marks the conclusion of the conceptual design phase and establishes the baseline reference concept.

  1. High Flux Isotope Reactor cold neutron source reference design concept

    International Nuclear Information System (INIS)

    In February 1995, Oak Ridge National Laboratory's (ORNL's) deputy director formed a group to examine the need for upgrades to the High Flux Isotope Reactor (HFIR) system in light of the cancellation of the Advanced neutron Source Project. One of the major findings of this study was that there was an immediate need for the installation of a cold neutron source facility in the HFIR complex. In May 1995, a team was formed to examine the feasibility of retrofitting a liquid hydrogen (LH2) cold source facility into an existing HFIR beam tube. The results of this feasibility study indicated that the most practical location for such a cold source was the HB-4 beam tube. This location provides a potential flux environment higher than the Institut Laue-Langevin (ILL) vertical cold source and maximizes the space available for a future cold neutron guide hall expansion. It was determined that this cold neutron beam would be comparable, in cold neutron brightness, to the best facilities in the world, and a decision was made to complete a preconceptual design study with the intention of proceeding with an activity to install a working LH2 cold source in the HFIR HB-4 beam tube. During the development of the reference design the liquid hydrogen concept was changed to a supercritical hydrogen system for a number of reasons. This report documents the reference supercritical hydrogen design and its performance. The cold source project has been divided into four phases: (1) preconceptual, (2) conceptual design and testing, (3) detailed design and procurement, and (4) installation and operation. This report marks the conclusion of the conceptual design phase and establishes the baseline reference concept

  2. The neutron distribution system of the new ultra-cold neutron source at the FRM II

    Energy Technology Data Exchange (ETDEWEB)

    Wlokka, Stephan; Frei, Andreas [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Techische Universitaet Muenchen, Lichtenbergstrasse 1, D-85747 Garching (Germany); Fierlinger, Peter; Paul, Stephan [Physik Department, Technische Universitaet Muenchen, James-Franck-Strasse 1, D-85748 Garching (Germany); Geltenbort, Peter [Institut Laue-Langevin, BP 156, 6, rue Jules Horowitz, 38042 Grenoble Cedex 9 (France)

    2013-07-01

    Ultra-cold neutrons (UCN) are neutrons which are totally reflected from a given material surface. Typical energies of UCN are below 300 neV and velocities below 8 m/s. Thus they can be stored in material or magnetic bottles for several hundreds of seconds. As such, UCN are excellent laboratories to study fundamental parameters, e.g. the free neutron lifetime or the electric dipole moment of the neutron. The new UCN source foreseen at the FRM II will deliver high UCN densities to four experimental areas. Hence a mechanism to distribute as many UCN as possible to these areas is needed. We have developed a high efficiency UCN switch for this purpose. This talk reports about a series of measurements conducted with this switch. There have been three types of measurements, testing the transmission, storage and surface properties of the switch.

  3. Development and Production Of An 805-MHz, 550 kW Pulsed Klystron For The Spallation Neutron Source

    International Nuclear Information System (INIS)

    The Spallation Neutron Source (SNS) is an accelerator-based neutron source being built in Oak Ridge, Tennessee, by the U.S. Department of Energy. The SNS will provide the most intense pulsed neutron beams in the world for scientific research and industrial development. CPI is supporting the effort by providing 550 kW pulsed klystrons for the superconducting portion of the accelerator. A total of 73 units are on order. The primary output power requirements are 550 kW peak, 49.5 kW average at 805 MHz, with an electron beam-to-rf conversion efficiency of 65% and an rf gain of 50 dB. To date, 25 units have been factory tested. Performance specifications, computer-model predictions, and operating results are presented

  4. Intense Pulsed Neutron Source progress report for 1991

    International Nuclear Information System (INIS)

    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

  5. 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.

  6. Neutron Source Facility Training Simulator Based on EPICS

    Energy Technology Data Exchange (ETDEWEB)

    Park, Young Soo; Wei, Thomas Y.; Vilim, Richard B.; Grelle, Austin L.; Dworzanski, Pawel L.; Gohar, Yousry

    2015-01-01

    A plant operator training simulator is developed for training the plant operators as well as for design verification of plant control system (PCS) and plant protection system (PPS) for the Kharkov Institute of Physics and Technology Neutron Source Facility. The simulator provides the operator interface for the whole plant including the sub-critical assembly coolant loop, target coolant loop, secondary coolant loop, and other facility systems. The operator interface is implemented based on Experimental Physics and Industrial Control System (EPICS), which is a comprehensive software development platform for distributed control systems. Since its development at Argonne National Laboratory, it has been widely adopted in the experimental physics community, e.g. for control of accelerator facilities. This work is the first implementation for a nuclear facility. The main parts of the operator interface are the plant control panel and plant protection panel. The development involved implementation of process variable database, sequence logic, and graphical user interface (GUI) for the PCS and PPS utilizing EPICS and related software tools, e.g. sequencer for sequence logic, and control system studio (CSS-BOY) for graphical use interface. For functional verification of the PCS and PPS, a plant model is interfaced, which is a physics-based model of the facility coolant loops implemented as a numerical computer code. The training simulator is tested and demonstrated its effectiveness in various plant operation sequences, e.g. start-up, shut-down, maintenance, and refueling. It was also tested for verification of the plant protection system under various trip conditions.

  7. Intense Pulsed Neutron Source progress report for 1991

    Energy Technology Data Exchange (ETDEWEB)

    Schriesheim, Alan

    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.

  8. Conceptual moderator studies for the Spallation Neutron Source short-pulse second target station

    Science.gov (United States)

    Gallmeier, F. X.; Lu, W.; Riemer, B. W.; Zhao, J. K.; Herwig, K. W.; Robertson, J. L.

    2016-06-01

    Candidate moderator configurations for a short-pulse second target station (STS) at the Oak Ridge National Laboratory Spallation Neutron Source (SNS) have been identified using a global optimizer framework built around the MCNPX particle transport code. Neutron brightness metrics were selected as the figure-of-merit. We assumed that STS would use one out of six proton pulses produced by an SNS accelerator upgraded to operate at 1.3 GeV proton energy, 2.8 MW power and 60 Hz repetition rate. The simulations indicate that the peak brightness can be increased by a factor of 5 and 2.5 on a per proton pulse basis compared to the SNS first target station for both coupled and decoupled para-hydrogen moderators, respectively. Additional increases by factors of 3 and 2 were demonstrated for coupled and decoupled moderators, respectively, by reducing the area of neutron emission from 100 × 100 mm2 to 20 × 20 mm2. This increase in brightness has the potential to translate to an increase of beam intensity at the instruments' sample positions even though the total neutron emission of the smaller moderator is less than that of the larger. This is especially true for instruments with small samples (beam dimensions). The increased fluxes in the STS moderators come at accelerated poison and de-coupler burnout and higher radiation-induced material damage rates per unit power, which overall translate into lower moderator lifetimes. A first effort was undertaken to group decoupled moderators into a cluster collectively positioning them at the peak neutron production zone in the target and having a three-port neutron emission scheme that complements that of a cylindrical coupled moderator.

  9. Conceptual moderator studies for the Spallation Neutron Source short-pulse second target station.

    Science.gov (United States)

    Gallmeier, F X; Lu, W; Riemer, B W; Zhao, J K; Herwig, K W; Robertson, J L

    2016-06-01

    Candidate moderator configurations for a short-pulse second target station (STS) at the Oak Ridge National Laboratory Spallation Neutron Source (SNS) have been identified using a global optimizer framework built around the MCNPX particle transport code. Neutron brightness metrics were selected as the figure-of-merit. We assumed that STS would use one out of six proton pulses produced by an SNS accelerator upgraded to operate at 1.3 GeV proton energy, 2.8 MW power and 60 Hz repetition rate. The simulations indicate that the peak brightness can be increased by a factor of 5 and 2.5 on a per proton pulse basis compared to the SNS first target station for both coupled and decoupled para-hydrogen moderators, respectively. Additional increases by factors of 3 and 2 were demonstrated for coupled and decoupled moderators, respectively, by reducing the area of neutron emission from 100 × 100 mm(2) to 20 × 20 mm(2). This increase in brightness has the potential to translate to an increase of beam intensity at the instruments' sample positions even though the total neutron emission of the smaller moderator is less than that of the larger. This is especially true for instruments with small samples (beam dimensions). The increased fluxes in the STS moderators come at accelerated poison and de-coupler burnout and higher radiation-induced material damage rates per unit power, which overall translate into lower moderator lifetimes. A first effort was undertaken to group decoupled moderators into a cluster collectively positioning them at the peak neutron production zone in the target and having a three-port neutron emission scheme that complements that of a cylindrical coupled moderator.

  10. Time analysis of the slow neutron field generated by the accelerating tube downhole

    International Nuclear Information System (INIS)

    Pulsed neutron logging (PNL) consists in the irradiation of rocks around the well by a pulsed periodic flux of fast neutrons generated by a portable accelerating tube and detection of thermal neutrons during pauses between the neutron pulses. The main aim of the PNL is determining the time distribution of thermal neutrons in the well and formation. At present the PNL response is considered as the sum of two exponentially decaying components, one related to the well and another one - to rock formation: J(t) = A1 exp (-λ1t) + A2 exp (-λ2t) . This is a result of homogenization of a neutron field in the borehole and formation space which is characterized by complicated radial structure and heterogeneous neutron properties. The time base of measurements T is subdivided into a set consisting of I narrow time windows Δt and the PNL response is formed as the series of neutron registration events Ni for each time window Δt with number i =1 to I (time neutron spectrum). Presented is a noise-immune algorithm for decomposition of the experimental time neutron spectrum into two components using the following overdetermined system of equations: Ni - Δt (λ1 + λ2) Σk=i Nk + (Δt)2 λ1λ2 Σk=i Σj=k Nj + [T - (i - 1) Δt][J'(T) - (λ1 + λ2) J(T)]Δt - J(T) Δt 0. Two amplitudes and two time decay constants of these components give an information about the neutron absorption cross-section and porosity of rocks. Presented are physical characteristics of new Russian PNL tools and examples illustrating the processing of PNL in oil wells. (author)

  11. Measurement of Neutrons Produced by Beam-Target Interactions via a Coaxial Plasma Accelerator

    Science.gov (United States)

    Cauble, Scott; Poehlmann, Flavio; Rieker, Gregory; Cappelli, Mark

    2011-10-01

    This poster presents a method to measure neutron yield from a coaxial plasma accelerator. Stored electrical energies between 1 and 19 kJ are discharged within a few microseconds across the electrodes of the coaxial gun, accelerating deuterium gas samples to plasma beam energies well beyond the keV energy range. The focus of this study is to examine the interaction of the plasma beam with a deuterated target by designing and fabricating a detector to measure neutron yield. Given the strong electromagnetic pulse associated with our accelerator, indirect measurement of neutrons via threshold-dependent nuclear activation serves as both a reliable and definitive indicator of high-energy particles for our application. Upon bombardment with neutrons, discs or stacks of metal foils placed near the deuterated target undergo nuclear activation reactions, yielding gamma-emitting isotopes whose decay is measured by a scintillation detector system. By collecting gamma ray spectra over time and considering nuclear cross sections, the magnitude of the original neutron pulse is inferred.

  12. Concept of DT fuel cycle for a fusion neutron source

    International Nuclear Information System (INIS)

    A concept of DT-fusion neutron source (FNS) with the neutron yield higher than 1018 neutrons per second is under design in Russia. Such a FNS is of interest for many applications: 1) basic and applied research (neutron scattering, etc); 2) testing the structural materials for fusion reactors; 3) control of sub-critical nuclear systems and 4) nuclear waste processing (including transmutation of minor actinides). This paper describes the fuel cycle concept of a compact fusion neutron source based on a small spherical tokamak (FNS-ST) with a MW range of DT fusion power and considers the key physics issues of this device. The major and minor radii are ∼0.5 and ∼0.3 m, magnetic field ∼1.5 T, heating power less than 15 MW and plasma current 1-2 MA. The system provides the fuel mixture with equal fractions of D and T (D:T = 1:1) for all FNS technology systems. (authors)

  13. Stability of high-speed lithium sheet jets for the neutron source in Boron Neutron Capture Therapy (BNCT)

    International Nuclear Information System (INIS)

    The stability of high-speed liquid lithium sheet jets was analytically studied for the neutron source in Boron Neutron Capture Therapy (BNCT), which makes cancers and tumors curable with cell-level selections and hence high QOL. The object of our research is to realize the thin and high-speed plane sheet jets of liquid lithium in a high-vacuum as an accelerator target. Linear analysis approach is made to the stability on thin plane sheet jets of liquid lithium in a high-vacuum, and then our analytical results were compared with the previous experimental ones. We proved that the waves of surface tension on thin lithium sheet jets in a high-vacuum are of supercritical flows and neutral stable under about 17.4 m/s in flow velocity and that the fast non-dispersive anti-symmetric waves are more significant than the very slow dispersive symmetric waves. We also formulated the equation of shrinking angle in isosceles-triangularly or isosceles-trapezoidal shrinking sheet jets corresponding to the Mach angle of supersonic gas flows. This formula states universally the physical meaning of Weber number of sheet jets on the wave of surface tension in supercritical flows. We obtained satisfactory prospects (making choice of larger flow velocity U and larger thickness of sheet a) to materialize a liquid target of accelerator in BNCT. (author)

  14. EXPERIENCE WITH COLLABORATIVE DEVELOPMENT FOR THE SPALLATION NEUTRON SOURCE FROM A PARTNER LAB PERSPECTIVE.

    Energy Technology Data Exchange (ETDEWEB)

    HOFF, L.T.

    2005-10-10

    Collaborative development and operation of large physics experiments is fairly common. Less common is the collaborative development or operation of accelerators. A current example of the latter is the Spallation Neutron Source (SNS). The SNS project was conceived as a collaborative effort between six DOE facilities. In the SNS case, the control system was also developed collaboratively. The SNS project has now moved beyond the collaborative development phase and into the phase where Oak Ridge National Lab (ORNL) is integrating contributions from collaborating ''partner labs'' and is beginning accelerator operations. In this paper, the author reflects on the benefits and drawbacks of the collaborative development of an accelerator control system as implemented for the SNS project from the perspective of a partner lab.

  15. Calibration of area monitors for neutrons used in clinical linear accelerators

    International Nuclear Information System (INIS)

    This work demonstrates the complexity and the necessary cares for the realization of measurements of neutron fields in rooms for radiotherapy treatment containing clinical accelerators. The acquaintance of the technical characteristics of the monitors and the periodic calibration are actions and fundamental procedures to guarantee traceability and the reliability of measurements

  16. Neutron physics and nuclear data measurements with accelerators and research reactors

    International Nuclear Information System (INIS)

    The report contains a collection of lectures devoted to the latest theoretical and experimental developments in the field of fast neutron physics and nuclear data measurements. The possibilities offered by particle accelerators and research reactors for research and technological applications in these fields are pointed out. Refs, figs and tabs

  17. Automatic pneumatic source-control system for positioning gamma and neutron calibration sources

    International Nuclear Information System (INIS)

    A microcomputer-based source-control system was developed to move gamma and neutron calibration sources into position for sample irradiation. In addition to monitoring interlocks and system status, the computer calculates for gamma sources the time required for a requested exposure at a specified distance. All system use data is stored, and monthly reports are generated

  18. Neutron pinhole camera investigations on temporal and spatial structures of plasma focus neutron source

    International Nuclear Information System (INIS)

    The neutron emission of the Frascati 1-MJ-plasma focus has been investigated over an energy range of 250 to 500kJ by means of a neutron pinhole camera, using a six-channel detector array. Single-shot neutron streak images, space- and time-resolved, are obtained with an axial resolution of 2 cm and a time resolution of about 5ns. - Results show that over 70% of the neutrons (i.e. more than 1011 neutrons per shot at 490kJ) are emitted from a co-axial cylindrical volume about 4cm long and less than 4cm in diameter at the anode tip. Neither axial nor radial motion of this main source is observed throughout the emission lasting 200ns FWHM typically. Simultaneous independent measurements show, for this zone, an isotropic neutron fluence (A=PHI (axial)/PHI (equat.)=0.97+-0.04), while the energy spectra still are anisotropic as reported previously. (author)

  19. Survey of Pulsed Neutron Source Methods for Multiplying Media

    International Nuclear Information System (INIS)

    In recent years there have existed two schools of thought on the most effective manner of obtaining measurements of the shutdown reactivity using pulsed neutron generators; these are (i) the conventional pulsed neutron source measurements with a repetitively pulsed source and (ii) methods based on a pseudo-random impulse response technique using cross-correlation between input and output. In both techniques the pertinent information obtained is identical, i.e. ideally both methods serve to determine the response function. The development of pulsed neutron source techniques on thermal systems for the purpose of reactivity measurements is traced from the early efforts of Sjöstrand to the recent (kβℓ) method. In the usual pulsed neutron source method, the Green's function of the subcritical assembly, the reactor response to a delta function source of neutrons, is the sought-after property. The exponential decay, exp(-αt), of the Green's function yields a spatially independent prompt neutron decay constant. The methods by which the reactivity is derived from the ct-measurement, e.g. the a-delayed critical measurement and the recent (kβℓ) method, are discussed. The fundamental modal treatments are examined in the light of the theory of the pulsed neutronsource techniques as developed for the (kβℓ) model. The implications of the pulsed neutron source theory to obtain precise decay constants and suitable data for the analysis of pulsed systems are considered. Experimental work is reviewed that shows the advantages as well as the limitations of the (kβℓ) technique. The use of pseudo-random impulse response methods with cross-correlation between the input and output for the determination of the Green's function of a multiplying assembly is also discussed. It is shown that the information obtained by the pseudo-random method is identical to that obtained from the repetitively pulsed method. Thus, this makes it possible to apply the methods developed for the

  20. Review of the Advanced Neutron Source (ANS) materials irradiation facilities

    International Nuclear Information System (INIS)

    The purpose of the workshop was to document as accurately as possible the present and future needs for neutron irradiation capacity and facilities as related to the design of the Advanced Neutron Source (ANS) which will be the next generation steady-state research reactor. The report provides the findings and recommendations of the working group. After introductory and background information is presented, the discussion includes the status of the ANS design, in particular in-core materials irradiation facilities design and important experimental parameters. The summary of workshop discussions describes a survey of irradiation-effects research community and opportunities for ex-core irradiation facilities. 20 refs., 2 figs., 4 tabs

  1. Measurement of ultracold neutrons produced by using Doppler-shifted Bragg reflection at a pulsed-neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Brun, T.O.; Carpenter, J.M.; Krohn, V.E.; Ringo, G.R.; Cronin, J.W.; Dombeck, T.W.; Lynn, J.W.; Werner, S.A.

    1979-01-01

    Ultracold neutrons (UCN) have been produced at the Argonne pulsed-neutron source by the Doppler shift of 400-m/s neutrons Bragg reflected from a moving crystal. The peak density of UCN produced at the crystal exceeds 0.1 n/cm/sup 3/.

  2. Applications of laser wakefield accelerator-based light sources

    Science.gov (United States)

    Albert, Félicie; Thomas, Alec G. R.

    2016-11-01

    Laser-wakefield accelerators (LWFAs) were proposed more than three decades ago, and while they promise to deliver compact, high energy particle accelerators, they will also provide the scientific community with novel light sources. In a LWFA, where an intense laser pulse focused onto a plasma forms an electromagnetic wave in its wake, electrons can be trapped and are now routinely accelerated to GeV energies. From terahertz radiation to gamma-rays, this article reviews light sources from relativistic electrons produced by LWFAs, and discusses their potential applications. Betatron motion, Compton scattering and undulators respectively produce x-rays or gamma-rays by oscillating relativistic electrons in the wakefield behind the laser pulse, a counter-propagating laser field, or a magnetic undulator. Other LWFA-based light sources include bremsstrahlung and terahertz radiation. We first evaluate the performance of each of these light sources, and compare them with more conventional approaches, including radio frequency accelerators or other laser-driven sources. We have then identified applications, which we discuss in details, in a broad range of fields: medical and biological applications, military, defense and industrial applications, and condensed matter and high energy density science.

  3. New concepts for compact accelerator/target for Boron Neutron Capture Therapy

    International Nuclear Information System (INIS)

    Two new target concepts, NIFTI and DISCOS, that enable a large reduction in the proton beam current needed to produce epithermal neutrons for BNCT (Boron Neutron Capture Therapy) are described. In the NIFTI concept, high energy neutrons produced by (p, n) reactions of 2.5 MeV protons on Li are down scattered to treatment energies (∼ 20 keV) by relatively thin layers of PbF2 and iron. In the DISCOS concept, treatment energy neutrons are produced directly in a succession of thin (∼ 1 micron) liquid Li films on rotating Be foils. These foils interact with a proton beam that operates just above threshold for the (p, n) reaction, with an applied DC field to re-accelerate the proton beam between the target foils

  4. An intercomparison of neutron measurments for a 25 MV x-ray radiotherapy accelerator.

    Science.gov (United States)

    Nath, R; Price, K W; Holeman, G R

    1980-01-01

    High-energy x-ray radiotherapy machines produce neutrons by photonuclear reactions which present a potential radiation hazard to the personnel and patient. A series of measurements of the neutron flux from a 25 MV x-ray linear accelerator, inside and outside the treatment room, have been performed using a multisphere spectrometer, Nemo dosimeter, and activation detectors. These results are compared with other mixed photon-neutron field measurements for the same machine performed using an argon/propane ionization chamber, silicon diode, track-etching detectors, and Monte Carlo calculations. It is found that these measurements agree with each other within a factor of two except for silicon diode measurements in the photon beam. Measured neutron spectra at various locations in the treatment room are also compared with the results of Monte Carlo transport calculations.

  5. Cold moderators for pulsed neutron sources

    International Nuclear Information System (INIS)

    This paper reviews cold moderators in pulsed sources and provides details of the performance of different cold moderator materials and configurations. Analytical forms are presented which describe wavelength spectra and emission time distributions. Several types of cooling arrangements used in pulsed moderators are described. Choices of materials are surveyed. The author examines some of the radiation damage effects in cold moderators, including the phenomenon of burping in irradiated cold solid methane

  6. Compact Short-Pulsed Electron Linac Based Neutron Sources for Precise Nuclear Material Analysis

    Science.gov (United States)

    Uesaka, M.; Tagi, K.; Matsuyama, D.; Fujiwara, T.; Dobashi, K.; Yamamoto, M.; Harada, H.

    2015-10-01

    An X-band (11.424GHz) electron linac as a neutron source for nuclear data study for the melted fuel debris analysis and nuclear security in Fukushima is under development. Originally we developed the linac for Compton scattering X-ray source. Quantitative material analysis and forensics for nuclear security will start several years later after the safe settlement of the accident is established. For the purpose, we should now accumulate more precise nuclear data of U, Pu, etc., especially in epithermal (0.1-10 eV) neutrons. Therefore, we have decided to modify and install the linac in the core space of the experimental nuclear reactor "Yayoi" which is now under the decommission procedure. Due to the compactness of the X-band linac, an electron gun, accelerating tube and other components can be installed in a small space in the core. First we plan to perform the time-of-flight (TOF) transmission measurement for study of total cross sections of the nuclei for 0.1-10 eV energy neutrons. Therefore, if we adopt a TOF line of less than 10m, the o-pulse length of generated neutrons should be shorter than 100 ns. Electronenergy, o-pulse length, power, and neutron yield are ~30 MeV, 100 ns - 1 micros, ~0.4 kW, and ~1011 n/s (~103 n/cm2/s at samples), respectively. Optimization of the design of a neutron target (Ta, W, 238U), TOF line and neutron detector (Ce:LiCAF) of high sensitivity and fast response is underway. We are upgrading the electron gun and a buncher to realize higher current and beam power with a reasonable beam size in order to avoid damage of the neutron target. Although the neutron flux is limited in case of the X-band electron linac based source, we take advantage of its short pulse aspect and availability for nuclear data measurement with a short TOF system. First, we form a tentative configuration in the current experimental room for Compton scattering in 2014. Then, after the decommissioning has been finished, we move it to the "Yayoi" room and perform

  7. High power neutron production targets

    Energy Technology Data Exchange (ETDEWEB)

    Wender, S. [Los Alamos National Lab., NM (United States)

    1996-06-01

    The author describes issues of concern in the design of targets and associated systems for high power neutron production facilities. The facilities include uses for neutron scattering, accelerator driven transmutation, accelerator production of tritium, short pulse spallation sources, and long pulse spallation sources. Each of these applications requires a source with different design needs and consequently different implementation in practise.

  8. Neutron dosimetry of a medical accelerator which produces X-ray with high energy at Iran

    International Nuclear Information System (INIS)

    Polycarbonate detector and albedo-neuton dosemeters which is innovated at radiiation protection of Atomic Energy Organization of Iran was used to measure neutron doses in and out of radiation field. Dose distribution in radiation field, out of field and around the collimator, at the head of equipment, and dose topology in the field is determined. The response of these dosimeters to neutron contamination dose at the therapy room, the corridor, control room was investigated. Also response to recieved dose of the personnel is determined. According to the results obtained, by increasing photon doses at a constant size of the field 20 mutipliy 20 2 cm, the neutron dose at the center of X radiation field, lineary by 2.8 multiply 10-3 sv/sv X rar coefficient and in a fix field 40 multiply 40 cm2 by 3.1 multiply 10-3 sv/svX ray is increased. Also in constant photon dose, by changing the field size, neutron doses variation at the center of radiation field is investigated. Outside radiation field, neutron leakage percentage at different sectors of the head is obtained. using albedo-neutron dosemeters tracks density register for thermal, albedo and fast neutrons at therapy room for photon doses of 1 sv respectively was 37, 5710, 5364. Also at the same condition, at the extreme end of corridor the particle track density was 11, 885, 800. Track density registered for thermal albedo and fast neutron at the control room for one month respectively was 256, 786, 745. At the back of therapy room the track density for thermal neutrons was 14408 track per square centimeters for one month, but at the same period no particle tracks was observed. Finally, three personnel of accelerator's section was monitored by neutron dosemeters

  9. Thermal-hydraulic studies of the Advanced Neutron Source cold source

    International Nuclear Information System (INIS)

    The Advanced Neutron Source (ANS), in its conceptual design phase at Oak Ridge National Laboratory, was to be a user-oriented neutron research facility producing the most intense steady-state flux of thermal and cold neutrons in the world. Among its many scientific applications, the production of cold neutrons was a significant research mission for the ANS. The cold neutrons come from two independent cold sources positioned near the reactor core. Contained by an aluminum alloy vessel, each cold source is a 410-mm-diam sphere of liquid deuterium that functions both as a neutron moderator and a cryogenic coolant. With nuclear heating of the containment vessel and internal baffling, steady-state operation requires close control of the liquid deuterium flow near the vessel's inner surface. Preliminary thermal-hydraulic analyses supporting the cold source design were performed with heat conduction simulations of the vessel walls and multidimensional computational fluid dynamics simulations of the liquid deuterium flow and heat transfer. This report presents the starting phase of a challenging program and describes the cold source conceptual design, the thermal-hydraulic feasibility studies of the containment vessel, and the future computational and experimental studies that were planned to verify the final design

  10. Universality of the acceleration due to gravity on the surface of a rapidly rotating neutron star

    International Nuclear Information System (INIS)

    On the surface of a rapidly rotating neutron star, the effective centrifugal force decreases the effective acceleration due to gravity (as measured in the rotating frame) at the equator while increasing the acceleration at the poles due to the centrifugal flattening of the star into an oblate spheroid. We compute the effective gravitational acceleration for relativistic rapidly rotating neutron stars and show that for a star with mass M, equatorial radius Re , and angular velocity Ω, the deviations of the effective acceleration due to gravity from the nonrotating case take on a universal form that depends only on the compactness ratio M/Re , the dimensionless square of the angular velocity Ω2Re3/GM, and the latitude on the star's surface. This dependence is universal, in that it has very little dependence on the neutron star's equation of state. The effective gravity is expanded in the slow-rotation limit to show the dependence on the effective centrifugal force, oblate shape of the star, and the quadrupole moment of the gravitational field. In addition, an empirical fit and simple formula for the effective gravity is found. We find that the increase in the acceleration due to gravity at the poles is of the same order of magnitude as the decrease in the effective acceleration due to gravity at the equator for all realistic value of mass, radius, and spin. For neutron stars that spin with frequencies near 600 Hz, the difference between the effective gravity at the poles and the equator is about 20%.

  11. Multiplication of Fast Neutrons Source Flux by Using Deuterium-Helium-3 Plasma

    OpenAIRE

    Mohammad Mahdavi; Maryam Shahbahrami

    2013-01-01

    The production of fast neutrons source is examined by using a thermal neutron flux inside plasma. In order to reach a favorable yield of fast neutrons flux, the parameters such as energy loss rate, reaction probability, and neutron absorption length are calculated. The nuclear conversion efficiency, , of thermal neutron to fast neutrons is obtained to be by calculating the physical parameters for the plasma designed.

  12. The comparison of four neutron sources for Prompt Gamma Neutron Activation Analysis (PGNAA) in vivo detections of boron

    International Nuclear Information System (INIS)

    A Prompt Gamma Ray Neutron Activation Analysis (PGNAA) system, incorporating an isotopic neutron source has been simulated using the MCNPX Monte Carlo code. In order to improve the signal to noise ratio different collimators and a filter were placed between the neutron source and the object. The effect of the positioning of the neutron beam and the detector relative to the object has been studied. In this work the optimisation procedure is demonstrated for boron. Monte Carlo calculations were carried out to compare the performance of the proposed PGNAA system using four different neutron sources (241Am/Be, 252Cf, 241Am/B, and DT neutron generator). Among the different systems the 252Cf neutron based PGNAA system has the best performance. (author)

  13. Neutronics studies for the ESS Source

    International Nuclear Information System (INIS)

    This paper presents the results of calculations on two alternative target designs for the ESS pulsed spallation source. A conventional target based on the current ISIS design is compared with a split target incorporating both wing and flux trap moderators. The results presented here focus on three issues, all of which are of general interest in the field of target-moderator systems. Firstly, the moderator performance is compared for the conventional and split target. For the purpose of the ESS study, the split target was found to offer no major advantage over a conventional target. Secondly, the variation of moderator performance with target diameter was examined. The results demonstrate that a flux trap moderator is significantly less sensitive to target diameter than wing moderators; thus a split target would be advantageous if a very large target diameter was found to be necessary. Thirdly, the performance of liquid para-hydrogen as a substitute for liquid methane (which would probably suffer unacceptable radiation damage on the ESS source) is evaluated. The results indicate that a suitable poisoned liquid H2 moderator could be an acceptable substitute for a similar poisoned liquid CH4 moderator. (author) 11 figs., 6 tabs., 6 refs

  14. Characterization of nuclear sources from neutron-neutron, proton-proton and neutron-proton correlation functions

    Energy Technology Data Exchange (ETDEWEB)

    Ghetti, R. E-mail: roberta.ghetti@kosufy.lu.se; Martensson, J.; Colonna, N.; Helgesson, J.; Jakobsson, B.; De Filippo, E.; Tagliente, G.; Lanzano, G.; Pantaleo, A.; Bellini, V.; Anzalone, A.; Carlen, L.; Cavallaro, S.; Celano, L.; D' Erasmo, G.; Di Santo, D.; Fiore, E.M.; Fokin, A.; Geraci, M.; Giustolisi, F.; Kuznetsov, A.; Mahboub, D.; Palazzolo, F.; Palomba, M.; Paticchio, V.; Riera, G.; Sperduto, M.L.; Sutera, C.; Urrata, M

    2000-07-03

    Two-neutron, two-proton and neutron-proton correlation functions have been measured simultaneously for the E/A=45 MeV {sup 58} Ni + {sup 27} Al reaction. Calculations from a statistical model have been compared to singles energy spectra as well as to total and gated correlation functions. This imposes very strong constraints on the model parameters. The use of directionally gated correlation functions helps to disentangle space and time information. Values of Gaussian radii, emission lifetimes, initial temperatures, source velocities and flow velocities are extracted. Correlation functions gated on total momentum of the nucleon pairs suggest that more energetic particles are emitted on a fast time scale ( < 100 fm / c ) and that the fraction of pre-equilibrium to equilibrium emission is larger for protons than for neutrons.

  15. Characterization of nuclear sources from neutron-neutron, proton-proton and neutron-proton correlation functions

    CERN Document Server

    Ghetti, R; Colonna, N; Helgesson, J; Jakobsson, B; De Filippo, E; Tagliente, G; Lanzanò, G; Pantaleo, A; Bellini, V; Anzalone, A; Carlén, L; Cavallaro, S; Celano, L; D'Erasmo, G; Di Santo, D; Fiore, E M; Fokin, A; Geraci, M; Giustolisi, F; Kuznetsov, A; Mahboub, D; Palazzolo, F; Palomba, M; Paticchio, V; Riera, G; Sperduto, M L; Sutera, C; Urrata, M

    2000-01-01

    Two-neutron, two-proton and neutron-proton correlation functions have been measured simultaneously for the E/A=45 MeV sup 5 sup 8 Ni + sup 2 sup 7 Al reaction. Calculations from a statistical model have been compared to singles energy spectra as well as to total and gated correlation functions. This imposes very strong constraints on the model parameters. The use of directionally gated correlation functions helps to disentangle space and time information. Values of Gaussian radii, emission lifetimes, initial temperatures, source velocities and flow velocities are extracted. Correlation functions gated on total momentum of the nucleon pairs suggest that more energetic particles are emitted on a fast time scale ( < 100 fm / c ) and that the fraction of pre-equilibrium to equilibrium emission is larger for protons than for neutrons.

  16. Polarized ionic source of the tandem accelerator in Kyoto University

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Masanobu; Kuwamoto, Shuichi; Takahashi, Seiji [Kyoto Univ. (Japan). Dept. of Physics] [and others

    1997-02-01

    A polarized ion source developed under the National Laboratory of High Energy Physics was transferred to the tandem accelerator in Kyoto University at beginning of 1993 to constitute a displacement of incidence into the accelerator. This was an atomic beam type polarized ion source, which is designed to adopt permanent magnets for 6 poles magnet to polarize the electron, to take out atomic nucleus on a shape of positive ion by ECR ionizer after transferring its polarization through transition using radio frequency (RFT), to make it negative ion by charge conversion using alkaline metal vapor, and to put it into the tandem accelerator. Test of the positive ion was finished at the National Laboratory of High Energy Physics, and test in Kyoto University was required after its negative ionization. As the estimated cost was unsufficient and entrance into the ion source facility in the tandem accelerator building was limited in Kyoto University, step of development was slow. Here is reported on present state of the ion source which is now operating stably. (G.K.)

  17. Application of a triga research reactor as the neutron source for a production neutron radiography facility

    International Nuclear Information System (INIS)

    GA Technologies Inc. (GA) has developed a Stationary Neutron Radiography System (SNRS) using a 250-1000 KW TRIGA reactor as the neutron source. The partially below ground reactor will be equipped with four vertical beam tubes originating in the reactor graphite reflector and installed tangential to the core to provide a strong current of thermal neutrons with minimum gamma-ray contamination. The vertical beam tubes interface with rugged component positioning systems designed to handle intact F-111 aircraft wings, partial A-10 aircraft wings, pyrotechnics, and other honeycomb aircraft structures. The SNRS will be equipped with real-time, near-real-time, and film-radiographic imaging systems to provide a broad spectrum of capability for detection or corrosion of entrained moisture in large aircraft panels. (author)

  18. Neutron activation analysis of essential elements in Multani mitti clay using miniature neutron source reactor

    International Nuclear Information System (INIS)

    Multani mitti clay was studied for 19 essential and other elements. Four different radio-assay schemes were adopted for instrumental neutron activation analysis (INAA) using miniature neutron source reactor. The estimated weekly intakes of Cr and Fe are high for men, women, pregnant and lactating women and children while intake of Co is higher in adult categories and Mn by pregnant women. Comparison of MM clay with other type of clays shows that it is a good source of essential elements. - Highlights: ► Multani mitti clay has been studied for 19 essential elements for human adequacy and safety using INAA and AAS. ► Weekly intakes for different consumer categories have been calculated and compared with DRIs. ► Comparison of MM with other type of clays depict that MM clay is a good source of essential elements.

  19. 76 FR 76327 - Installation of Radiation Alarms for Rooms Housing Neutron Sources

    Science.gov (United States)

    2011-12-07

    ... COMMISSION 10 CFR Part 73 Installation of Radiation Alarms for Rooms Housing Neutron Sources AGENCY: Nuclear... radiation alarms in rooms housing neutron sources. DATES: Submit comments by February 21, 2012. Comments..., Radiation Safety for Research. Mr. Hamawy is concerned about the security of neutron sources. III....

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

    International Nuclear Information System (INIS)

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

  1. Optical diagnostics for Frankfurt Neutron Source

    OpenAIRE

    Reichau, Hermine; Meusel, Oliver; Ratzinger, Ulrich; Wagner, Christopher

    2011-01-01

    A non-in­ter­cep­tive op­ti­cal di­ag­nos­tic sys­tem on the basis of beam to­mog­ra­phy, was de­vel­oped for the planned Frank­furt Neu­tron Source (FRANZ). The pro­ton dri­ver linac of FRANZ will pro­vide en­er­gies up to 2.0 MeV. The mea­sure­ment de­vice will non-in­ter­cep­tively de­rive re­quired beam pa­ra­me­ters at the end of the LEBT at beam en­er­gies of 120 keV and a cur­rent of 200 mA. On a nar­row space of 351.2 mm length a ro­tat­able to­mog­ra­phy tank will per­form a multi-tu...

  2. Neutron induced activation in the EVEDA accelerator materials: Implications for the accelerator maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Sanz, J. [Department of Power Engineering, Universidad Nacional de Educacion a Distancia (UNED), C/Juan del Rosal 12, 28040 Madrid (Spain); Institute of Nuclear Fusion, UPM, 28006 Madrid (Spain)], E-mail: jsanz@ind.uned.es; Garcia, M.; Sauvan, P.; Lopez, D. [Department of Power Engineering, Universidad Nacional de Educacion a Distancia (UNED), C/Juan del Rosal 12, 28040 Madrid (Spain); Institute of Nuclear Fusion, UPM, 28006 Madrid (Spain); Moreno, C.; Ibarra, A.; Sedano, L. [CIEMAT, 28040 Madrid (Spain)

    2009-04-30

    The Engineering Validation and Engineering Design Activities (EVEDA) phase of the International Fusion Materials Irradiation Facility project should result in an accelerator prototype for which the analysis of the dose rates evolution during the beam-off phase is a necessary task for radioprotection and maintenance feasibility purposes. Important aspects of the computational methodology to address this problem are discussed, and dose rates for workers inside the accelerator vault are assessed and found to be not negligible.

  3. Monte Carlo analysis of accelerator-driven systems studies on spallation neutron yield and energy gain

    CERN Document Server

    Hashemi-Nezhad, S R; Westmeier, W; Bamblevski, V P; Krivopustov, M I; Kulakov, B A; Sosnin, A N; Wan, J S; Odoj, R

    2001-01-01

    The neutron yield in the interaction of protons with lead and uranium targets has been studied using the LAHET code system. The dependence of the neutron multiplicity on target dimensions and proton energy has been calculated and the dependence of the energy amplification on the proton energy has been investigated in an accelerator-driven system of a given effective multiplication coefficient. Some of the results are compared with experimental findings and with similar calculations by the DCM/CEM code of Dubna and the FLUKA code system used in CERN. (14 refs).

  4. Neutron source investigations in support of the cross section program at the Argonne Fast-Neutron Generator

    International Nuclear Information System (INIS)

    Experimental methods related to the production of neutrons for cross section studies at the Argonne Fast-Neutron Generator are reviewed. Target assemblies commonly employed in these measurements are described, and some of the relevant physical properties of the neutron source reactions are discussed. Various measurements have been performed to ascertain knowledge about these source reaction that is required for cross section data analysis purposes. Some results from these studies are presented, and a few specific examples of neutron-source-related corrections to cross section data are provided. 16 figures, 3 tables

  5. Recommendation for a injector-cyclotron and ion sources for the acceleration of heavy ions and polarized protons and deuterons

    International Nuclear Information System (INIS)

    It was decided to accelerate both heavy and light ions with the open-sector cyclotron. The injector SPS1, was used for light ions and SPS2 for heavy ions. Provision was also made for the acceleration of polarized neutrons. To enable this, the injector must have an axial injection system. The working of a source of polarized ions and inflectors for an axial injection system is discussed. The limitations of the open-sector cyclotron on the acceleration of heavy ions are also dealt with. The following acceleration/ion source combinations are discussed: i) The open-sector cyclotron and a k=40 injector cyclotron with a Penning ion source, and a stripper between the injector and the open-sector cyclotron and also a source of polarized protons and deuterons; ii) The acceleration/ion source combination with the addition of electron beam ion sources; iii) The open-sector cyclotron and a k=11 injector cyclotron with a electron beam ion source and a source of polarized protons and deuterons

  6. LPA Beamformer for Tracking Nonstationary Accelerated Near-Field Sources

    Directory of Open Access Journals (Sweden)

    Amira S. Ashour

    2014-01-01

    Full Text Available In this paper, a computationally very efficient algorithm for direction of arrival (DOA as well as range parameter estimation is proposed for near-field narrowband nonstationary accelerated moving sources. The proposed algorithm based on the local polynomial approximation (LPA beamformer, which proves its efficiency with far-field applications. The LPA estimates the instantaneous values of the direction of arrival, angular velocity, acceleration as well as the range parameters of near-field sources using weighted least squares approach which based on Taylor series. The performance efficiency of the LPA beamformer to estimate the DOAs of near-field sources is evaluated and compared with the Recursive Expectation-Maximization (REM method. The comparison is done using standard deviation of DOA estimation error as well as for range versus signal to noise ratio (SNR. The simulation results show that LPA beamformer outperform REM1 in signal-to-noise ratio requirements.

  7. Backscattering at a pulsed neutron source, the MUSICAL instrument

    International Nuclear Information System (INIS)

    In the first part the principles of the neutron backscattering method are described and some simple considerations about the energy resolution and the intensity are presented. A prototype of a backscattering instrument, the first Juelich instrument, is explained in some detail and a representative measurement is shown which was performed on the backscattering instrument IN10 at the ILL in Grenoble. In the second part a backscattering instrument designed for a pulsed neutron source is proposed. It is shown that a rather simple modification, which consists in the replacement of the Doppler drive of the conventional backscattering instrument by a multi silicon monochromator crystal (MUSICAL) leads to a very effective instrument, benefitting from the peak flux of the pulsed source. ((orig.))

  8. The advanced neutron source research and development plan

    Energy Technology Data Exchange (ETDEWEB)

    Selby, D.L.

    1995-08-01

    The Advanced Neutron Source (ANS) is being designed as a user-oriented neutron research laboratory centered around the most intense continuous beams of thermal and subthermal neutrons in the world (an order of magnitude more intense than beams available from the most advanced existing reactors). The ANS will be built around a new research reactor of 330-MW fission power, producing an unprecedented peak thermal flux of >7 {center_dot} 10{sup 19} {center_dot} m{sup -2} {center_dot} s{sup -1}. Primarily a research facility, the ANS will accommodate more than 1000 academic, industrial, and government researchers each year. They will conduct basic research in all branches of science as well as applied research leading to better understanding of new materials, including high temperature super conductors, plastics, and thin films. Some 48 neutron beam stations will be set up in the ANS beam rooms and the neutron guide hall for neutron scattering and for fundamental and nuclear physics research. There also will be extensive facilities for materials irradiation, isotope production, and analytical chemistry. The top level work breakdown structure (WBS) for the project. As noted in this figure, one component of the project is a research and development (R&D) program (WBS 1.1). This program interfaces with all of the other project level two WBS activities. Because one of the project guidelines is to meet minimum performance goals without relying on new inventions, this R&D activity is not intended to produce new concepts to allow the project to meet minimum performance goals. Instead, the R&D program will focus on the four objectives described.

  9. The Advanced Neutron Source research and development plan

    International Nuclear Information System (INIS)

    The Advanced Neutron Source (ANS) is being designed as a user-oriented neutron research laboratory centered around the most intense continuous beams of thermal and subthermal neutrons in the world. The ANS will be built around a new research reactor of ∼ 330 MW fission power, producing an unprecedented peak thermal flux of > 7 x 1019 M-2 · S-1. Primarily a research facility, the ANS will accommodate more than 1000 academic, industrial, and government researchers each year. They will conduct basic research in all branches of science-as well as applied research-leading to better understanding of new materials, including high temperature super conductors, plastics, and thin films. Some 48 neutron beam stations will be set up in the ANS beam rooms and the neutron guide hall for neutron scattering and for fundamental and nuclear physics research. There also will be extensive facilities for materials irradiation, isotope production, and analytical chemistry. The R ampersand D program will focus on the four objectives: Address feasibility issues; provide analysis support; evaluate options for improvement in performance beyond minimum requirements; and provide prototype demonstrations for unique facilities. The remainder of this report presents (1) the process by which the R ampersand D activities are controlled and (2) a discussion of the individual tasks that have been identified for the R ampersand D program, including their justification, schedule and costs. The activities discussed in this report will be performed by Martin Marietta Energy Systems, Inc. (MMES) through the Oak Ridge National Laboratory (ORNL) and through subcontracts with industry, universities, and other national laboratories. It should be noted that in general a success path has been assumed for all tasks

  10. The advanced neutron source research and development plan

    International Nuclear Information System (INIS)

    The Advanced Neutron Source (ANS) is being designed as a user-oriented neutron research laboratory centered around the most intense continuous beams of thermal and subthermal neutrons in the world (an order of magnitude more intense than beams available from the most advanced existing reactors). The ANS will be built around a new research reactor of 330-MW fission power, producing an unprecedented peak thermal flux of >7 · 1019 · m-2 · s-1. Primarily a research facility, the ANS will accommodate more than 1000 academic, industrial, and government researchers each year. They will conduct basic research in all branches of science as well as applied research leading to better understanding of new materials, including high temperature super conductors, plastics, and thin films. Some 48 neutron beam stations will be set up in the ANS beam rooms and the neutron guide hall for neutron scattering and for fundamental and nuclear physics research. There also will be extensive facilities for materials irradiation, isotope production, and analytical chemistry. The top level work breakdown structure (WBS) for the project. As noted in this figure, one component of the project is a research and development (R ampersand D) program (WBS 1.1). This program interfaces with all of the other project level two WBS activities. Because one of the project guidelines is to meet minimum performance goals without relying on new inventions, this R ampersand D activity is not intended to produce new concepts to allow the project to meet minimum performance goals. Instead, the R ampersand D program will focus on the four objectives described

  11. Application of particle transport code PHITS for design of J-PARC 1MW spallation neutron source and its validation

    International Nuclear Information System (INIS)

    Japan Spallation Neutron Source (JSNS) is one of major experimental facilities in Japan Proton Accelerator Research Complex (J-PARC). JSNS operated by 3-GeV and 1-MW pulsed proton beams has the highest class neutron intensity in the world. In the design stage, aiming to the best neutronic performance, the PHITS code was fully applied to JSNS neutronics designs and several thousands calculation cases were done with complicated models. Not only optimization of neutronic performance, but also shielding calculation, nuclear heat estimation for the engineering design, residual radioactivity estimation for the cask design and radiation damage estimation for the life and maintenance design were done with the PHITS code. JSNS is one of the first facilities in the world fully adapted such a simulation code to the neutronics design. In these calculations, note that the particle energy change from GeV to meV (12 decades) and neutron fluxes reduce by 10 decades or more. To confirm the reliability of these calculations, neutron spectral intensities were measured. As a result, the measured values were good agreement with the calculated values. We could confirm that the PHITS were reliable for such a design calculation. (author)

  12. Approaches to instrument design at pulsed neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, R.K.

    1997-04-14

    A number of tools are used in the design of scattering instruments for pulsed neutron sources. Initial design is based largely on simple analytical calculations. More complicated analytical calculations and Monte Carlo simulations come into play as the design is optimized to maximize the data rate and to improve the data quality. Examples are used to illustrate the relative roles of these different computational tools. Areas are also identified where appropriate computational tools are currently lacking.

  13. Detection of supernova neutrinos at spallation neutron sources

    OpenAIRE

    Huang, Ming-Yang; Guo, Xin-Heng; Young, Bing-Lin

    2015-01-01

    After considering the supernova shock effects, the Mikheyev-Smirnov-Wolfenstein effects, the neutrino collective effects, and the Earth matter effects, the detection of supernova neutrinos at China Spallation Neutron Sources is studied and the event numbers of different flavor supernova neutrinos observed through various reaction channels are calculated with the neutrino energy spectra described by the Fermi-Dirac distribution and "beta fit" distribution respectively. Furthermore, the numeric...

  14. Calculation of neutron flux in the presence of a source

    International Nuclear Information System (INIS)

    Neutron sources are introduced into the reactors to initiate the chain reaction. For safety reasons, we have to know the distribution and evolution of the flux throughout the startup phase. The flux is calculated iteratively but convergence of the process can slow down arbitrarily as we approach criticality. A calculation method is presented, with a convergence speed which does not depend on the negative reactivity when it is small. (author). 7 refs

  15. Use of accelerator mass spectrometry in the dosimetry of Hiroshima neutrons

    Science.gov (United States)

    Straume, T.; Finkel, R. C.; Eddy, D.; Kubik, P. W.; Gove, H. E.; Sharma, P.; Fujita, S.; Hoshi, M.

    1990-12-01

    A substantial discrepancy exists between the measured values for thermal neutron activation and the values calculated using the new A-bomb dosimetry system, DS86. As part of a joint US-Japan effort aimed at resolving this discrepancy, we have shown that 36Cl/Cl in mineral samples (i.e., concrete, granite, tiles) can be measured with sufficient precision using accelerator mass spectrometry (AMS) to quantify the very low thermal neutron activation levels at distances between 1000 and 2000 m from the hypocenter in Hiroshima. Our initial measurement results show that activation of Cl by the bomb neutrons disagree with calculations based on the new DS86 dosimetry system (measurements of 36Cl at 1450 m from the hypocenter indicate thermal neutron activation that is ˜15 times higher than obtained from DS86 calculations; discrepancies are even larger at 1606 m). This is a preliminary report of work in progress. The principal objectives of this work are to reconstruct the thermal neutron fluence as a function of distance from the hypocenters in both Hiroshima and Nagasaki using 36Cl/Cl and obtain information about fast neutron fluence.

  16. Oak Ridge Spallation Neutron Source (ORSNS) target station design integration

    Energy Technology Data Exchange (ETDEWEB)

    McManamy, T.; Booth, R.; Cleaves, J.; Gabriel, T. [and others

    1996-06-01

    The conceptual design for a 1- to 3-MW short pulse spallation source with a liquid mercury target has been started recently. The design tools and methods being developed to define requirements, integrate the work, and provide early cost guidance will be presented with a summary of the current target station design status. The initial design point was selected with performance and cost estimate projections by a systems code. This code was developed recently using cost estimates from the Brookhaven Pulsed Spallation Neutron Source study and experience from the Advanced Neutron Source Project`s conceptual design. It will be updated and improved as the design develops. Performance was characterized by a simplified figure of merit based on a ratio of neutron production to costs. A work breakdown structure was developed, with simplified systems diagrams used to define interfaces and system responsibilities. A risk assessment method was used to identify potential problems, to identify required research and development (R&D), and to aid contingency development. Preliminary 3-D models of the target station are being used to develop remote maintenance concepts and to estimate costs.

  17. Neutron interrogation of actinides with a 17 MeV electron accelerator and first results from photon and neutron interrogation non-simultaneous measurements combination

    Energy Technology Data Exchange (ETDEWEB)

    Sari, A., E-mail: adrien.sari@cea.fr [CEA, LIST, Laboratoire Capteurs et Architectures Electroniques, 91191 Gif-sur-Yvette Cedex (France); Carrel, F.; Lainé, F. [CEA, LIST, Laboratoire Capteurs et Architectures Electroniques, 91191 Gif-sur-Yvette Cedex (France); Lyoussi, A. [CEA, DEN, 13108 Saint-Paul-Lez-Durance Cedex (France)

    2013-10-01

    In this article, we demonstrate the feasibility of neutron interrogation using the conversion target of a 17 MeV linear electron accelerator as a neutron generator. Signals from prompt neutrons, delayed neutrons, and delayed gamma-rays, emitted by both uranium and plutonium samples were analyzed. First results from photon and neutron interrogation non-simultaneous measurements combination are also reported in this paper. Feasibility of this technique is shown in the frame of the measurement of uranium enrichment. The latter was carried out by combining detection of prompt neutrons from thermal fission and delayed neutrons from photofission, and by combining delayed gamma-rays from thermal fission and delayed gamma-rays from photofission.

  18. Radiative neutron capture as a counting technique at pulsed spallation neutron sources: a review of current progress

    Science.gov (United States)

    Schooneveld, E. M.; Pietropaolo, A.; Andreani, C.; Perelli Cippo, E.; Rhodes, N. J.; Senesi, R.; Tardocchi, M.; Gorini, G.

    2016-09-01

    Neutron scattering techniques are attracting an increasing interest from scientists in various research fields, ranging from physics and chemistry to biology and archaeometry. The success of these neutron scattering applications is stimulated by the development of higher performance instrumentation. The development of new techniques and concepts, including radiative capture based neutron detection, is therefore a key issue to be addressed. Radiative capture based neutron detectors utilize the emission of prompt gamma rays after neutron absorption in a suitable isotope and the detection of those gammas by a photon counter. They can be used as simple counters in the thermal region and (simultaneously) as energy selector and counters for neutrons in the eV energy region. Several years of extensive development have made eV neutron spectrometers operating in the so-called resonance detector spectrometer (RDS) configuration outperform their conventional counterparts. In fact, the VESUVIO spectrometer, a flagship instrument at ISIS serving a continuous user programme for eV inelastic neutron spectroscopy measurements, is operating in the RDS configuration since 2007. In this review, we discuss the physical mechanism underlying the RDS configuration and the development of associated instrumentation. A few successful neutron scattering experiments that utilize the radiative capture counting techniques will be presented together with the potential of this technique for thermal neutron diffraction measurements. We also outline possible improvements and future perspectives for radiative capture based neutron detectors in neutron scattering application at pulsed neutron sources.

  19. Radiative neutron capture as a counting technique at pulsed spallation neutron sources: a review of current progress.

    Science.gov (United States)

    Schooneveld, E M; Pietropaolo, A; Andreani, C; Perelli Cippo, E; Rhodes, N J; Senesi, R; Tardocchi, M; Gorini, G

    2016-09-01

    Neutron scattering techniques are attracting an increasing interest from scientists in various research fields, ranging from physics and chemistry to biology and archaeometry. The success of these neutron scattering applications is stimulated by the development of higher performance instrumentation. The development of new techniques and concepts, including radiative capture based neutron detection, is therefore a key issue to be addressed. Radiative capture based neutron detectors utilize the emission of prompt gamma rays after neutron absorption in a suitable isotope and the detection of those gammas by a photon counter. They can be used as simple counters in the thermal region and (simultaneously) as energy selector and counters for neutrons in the eV energy region. Several years of extensive development have made eV neutron spectrometers operating in the so-called resonance detector spectrometer (RDS) configuration outperform their conventional counterparts. In fact, the VESUVIO spectrometer, a flagship instrument at ISIS serving a continuous user programme for eV inelastic neutron spectroscopy measurements, is operating in the RDS configuration since 2007. In this review, we discuss the physical mechanism underlying the RDS configuration and the development of associated instrumentation. A few successful neutron scattering experiments that utilize the radiative capture counting techniques will be presented together with the potential of this technique for thermal neutron diffraction measurements. We also outline possible improvements and future perspectives for radiative capture based neutron detectors in neutron scattering application at pulsed neutron sources. PMID:27502571

  20. Colliding Neutron Stars as the Source of Heavy Elements

    Science.gov (United States)

    Kohler, Susanna

    2016-09-01

    Where do the heavy elements the chemical elements beyond iron in our universe come from? One of the primary candidate sources is the merger of two neutron stars, but recent observations have cast doubt on this model. Can neutron-star mergers really be responsible?Elements from Collisions?Periodic table showing the origin of each chemical element. Those produced by the r-process are shaded orange and attributed to supernovae in this image; though supernovae are one proposed source of r-process elements, an alternative source is the merger of two neutron stars. [Cmglee]When a binary-neutron-star system inspirals and the two neutron stars smash into each other, a shower of neutrons are released. These neutrons are thought to bombard the surrounding atoms, rapidly producing heavy elements in what is known as r-process nucleosynthesis.So could these mergers be responsible for producing the majority of the universes heavy r-process elements? Proponents of this model argue that its supported by observations. The overall amount of heavy r-process material in the Milky Way, for instance, is consistent with the expected ejection amounts from mergers, based both on predicted merger rates for neutron stars in the galaxy, and on the observed rates of soft gamma-ray bursts (which are thought to accompany double-neutron-star mergers).Challenges from Ultra-Faint DwarfsRecently, however, r-process elements have been observed in ultra-faint dwarf satellite galaxies. This discovery raises two major challenges to the merger model for heavy-element production:When neutron stars are born during a core-collapse supernova, mass is ejected, providing the stars with asymmetric natal kicks. During the second collapse in a double-neutron-star binary, wouldnt the kick exceed the low escape velocity of an ultra-faint dwarf, ejecting the binary before it could merge and enrich the galaxy?Ultra-faint dwarfs have very old stellar populations and the observation of r-process elements in these stars

  1. Advanced Neutron Source: Plant Design Requirements. Revision 4

    Energy Technology Data Exchange (ETDEWEB)

    1990-07-01

    The Advanced Neutron Source will be a new world-class facility for research using hot, thermal, cold, and ultra-cold neutrons. The heart of the facility will be a 330-MW (fission), heavy-water cooled and heavy-water moderated reactor. The reactor will be housed in a central reactor building, with supporting equipment located in an adjoining reactor support building. An array of cold neutron guides will fan out into a large guide hall, housing about 30 neutron research stations. Appropriate office, laboratory, and shop facilities will be included to provide a complete facility for users. The ANS is scheduled to begin operation at the Oak Ridge National Laboratory early in the next decade. This PDR document defines the plant-level requirements for the design, construction, and operation of ANS. It also defines and provides input to the individual System Design Description (SDD) documents. Together, this PDR document and the set of SDD documents will define and control the baseline configuration of ANS.

  2. Methods for lipid nanostructure investigation at neutron and synchrotron sources

    Science.gov (United States)

    Kiselev, M. A.

    2011-03-01

    A lipid membrane is a main component of biological membranes. Contemporary bionanotechnologies use phospholipids and ceramides as basic components of drugs and cosmetic preparations. Phospholipids-based nanoparticles are used as drug carriers. Effective development of bionanotechnologies in Russia calls for creation of physical methods to diagnose the particle nanostructure which would be promising for application in pharmacology. Radiation with wavelengths of 1-10 Å is an adequate instrument for detecting the nanostructure of lipid bi- and monolayers. The review deals with methods that apply neutron scattering and synchrotron radiation for studying nanostructures of lipid membranes, phospholipid nanoparticles, and phospholipid monolayers on a water surface by techniques of diffraction, small-angle scattering, and reflectometry. The importance of the mutually complementary application of neutron and synchrotron radiation for solving urgent problems of membrane biophysics, microbiology, dermapharmacology, and bionanotechnologies is demonstrated by particular examples of studies of phospholipid membranes and ceramide-based membranes. The efficiency of development and application of new methods for solving urgent problems of biophysics is shown. The review is written on the basis of results obtained over the period of 1999-2010 at the Joint Institute for Nuclear Research (JINR) Laboratory of Neutron Physics in collaboration with the Pharmaceutical Departments of universities of France (Paris-Sud, Chatenay Malabry) and Germany (Martin Luther University, Halle). The experiments were performed at various European and Russian neutron and synchrotron sources.

  3. Miniature neutron source reactor burnup calculations using IRBURN code system

    International Nuclear Information System (INIS)

    Highlights: ► Fuel consumption of Iranian MNSR during 15 years of operation has been investigated. ► Calculations have been performed by the IRBURN code. Precision and accuracy of the implemented model has been validated. ► Our study shows the consumption rate of MNSR is about 1%. - Abstract: Fuel consumption of Iranian miniature neutron source reactor (MNSR) during 15 years of operation has been investigated. Reactor core neutronic parameters such as flux and power distributions, control rod worth and effective multiplication factor at BOL and after 15 years of irradiation has been calculated. The Monte Carlo-based depletion code system IRBURN has been used for studying the reactor core neutronic parameters as well as the isotopic inventory of the fuel during burnup. The precision and accuracy of the implemented model has been verified via validation the results for neutronic parameters in the MNSR final safety analysis report. The results show that keff decreases from 1.0034 to 0.9897 and the total U-235 consumption in the core is about 13.669 g after 15 years of operational time. Finally, our studying shows the consumption rate of MNSR is about 1%.

  4. Neutron data for accelerator-driven transmutation technologies. Annual Report 2002/2003

    Energy Technology Data Exchange (ETDEWEB)

    Blomgren, J.; Hildebrand, A.; Mermod, P.; Olsson, N.; Pomp, S.; Oesterlund, M. [Uppsala Univ. (Sweden). Dept. for Neutron Research

    2003-08-01

    The project NATT, Neutron data for Accelerator-driven Transmutation Technology, is performed within the nuclear reactions group of the Department for neutron research, Uppsala university. The activities of the group is directed towards experimental studies of nuclear reaction probabilities of importance for various applications, like transmutation of nuclear waste, biomedical effects and electronics reliability. The experimental work is primarily undertaken at the The Svedberg Laboratory (TSL) in Uppsala, where the group has previously developed two world-unique instruments, MEDLEY and SCANDAL. Highlights from the past year: Analysis and documentation has been finalized of previously performed measurements of elastic neutron scattering from carbon and lead at 96 MeV. The precision in the results surpasses all previous data by at least an order of magnitude. These measurements represent the highest energy in neutron scattering where the ground state has been resolved. The results show that all previous theory work has underestimated the probability for neutron scattering at the present energy by 0-30 %. A new method for measurements of absolute probabilities for neutron-induced nuclear reactions with experimental techniques only has been developed. Previously, only two such methods have been known. One student has reached his PhD exam. Two PhD students have been accepted. TSL has decided to build a new neutron beam facility with significantly improved performance for these, and similar, activities. A new instrument for measurements of inelastic neutron scattering has been built, tested and found to meet the specifications. This work has been performed in collaboration with two French research groups from Caen and Nantes. The instrument is intended to be used for a series of experiments during the coming years. Previous work by the group on nuclear data for assessment of electronics reliability has lead to a new industry standard in the USA.

  5. China Experimental Fast Reactor(CEFR)——Criterion of Criticality for Reactor With External Neutron Source

    Institute of Scientific and Technical Information of China (English)

    ZHAOYu-sen

    2003-01-01

    There is a neutron source with 109 s-1 neutrons in core of CEFR during start up test and operation of CEFR. For judging the criticality of reactor with external neutron source and near criticality, it is important that the neutron level changes in core with time must be understood after introducing positive reactivity to core with external neutron source.

  6. Development of a Tandem-Electrostatic-Quadrupole facility for Accelerator-Based Boron Neutron Capture Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kreiner, A.J., E-mail: kreiner@tandar.cnea.gov.ar [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica, Av. Gral Paz 1499, 1650 San Martin, Buenos Aires (Argentina)] [Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin (Argentina)] [CONICET, Buenos Aires (Argentina); Castell, W. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica, Av. Gral Paz 1499, 1650 San Martin, Buenos Aires (Argentina); Di Paolo, H. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica, Av. Gral Paz 1499, 1650 San Martin, Buenos Aires (Argentina)] [Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin (Argentina); Baldo, M. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica, Av. Gral Paz 1499, 1650 San Martin, Buenos Aires (Argentina); Bergueiro, J. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica, Av. Gral Paz 1499, 1650 San Martin, Buenos Aires (Argentina)] [CONICET, Buenos Aires (Argentina)

    2011-12-15

    We describe the present status of an ongoing project to develop a Tandem-ElectroStatic-Quadrupole (TESQ) accelerator facility for Accelerator-Based (AB)-BNCT. The project final goal is a machine capable of delivering 30 mA of 2.4 MeV protons to be used in conjunction with a neutron production target based on the {sup 7}Li(p,n){sup 7}Be reaction. The machine currently being constructed is a folded TESQ with a high-voltage terminal at 0.6 MV. We report here on the progress achieved in a number of different areas.

  7. Initial global 2-D shielding analysis for the Advanced Neutron Source core and reflector

    Energy Technology Data Exchange (ETDEWEB)

    Bucholz, J.A.

    1995-08-01

    This document describes the initial global 2-D shielding analyses for the Advanced Neutron Source (ANS) reactor, the D{sub 2}O reflector, the reflector vessel, and the first 200 mm of light water beyond the reflector vessel. Flux files generated here will later serve as source terms in subsequent shielding analyses. In addition to reporting fluxes and other data at key points of interest, a major objective of this report was to document how these analyses were performed, the phenomena that were included, and checks that were made to verify that these phenomena were properly modeled. In these shielding analyses, the fixed neutron source distribution in the core was based on the `lifetime-averaged` spatial power distribution. Secondary gamma production cross sections in the fuel were modified so as to account intrinsically for delayed fission gammas in the fuel as well as prompt fission gammas. In and near the fuel, this increased the low-energy gamma fluxes by 50 to 250%, but out near the reflector vessel, these same fluxes changed by only a few percent. Sensitivity studies with respect to mesh size were performed, and a new 2-D mesh distribution developed after some problems were discovered with respect to the use of numerous elongated mesh cells in the reflector. All of the shielding analyses were performed sing the ANSL-V 39n/44g coupled library with 25 thermal neutron groups in order to obtain a rigorous representation of the thermal neutron spectrum throughout the reflector. Because of upscatter in the heavy water, convergence was very slow. Ultimately, the fission cross section in the various materials had to be artificially modified in order to solve this fixed source problem as an eigenvalue problem and invoke the Vondy error-mode extrapolation technique which greatly accelerated convergence in the large 2-D RZ DORT analyses. While this was quite effective, 150 outer iterations (over energy) were still required.

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

    International Nuclear Information System (INIS)

    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 20o with length of system 15 cm

  9. Procedure to measure the neutrons spectrum around a lineal accelerator for radiotherapy

    International Nuclear Information System (INIS)

    An experimental procedure was developed, by means of Bonner spheres, to measure the neutrons spectrum around Linacs of medical use that only requires of a single shot of the accelerator; to this procedure we denominate Planetary or Isocentric method. One of the problems associated to the neutrons spectrum measurement in a radiotherapy room with lineal accelerator is because inside the room a mixed, intense and pulsed radiation field takes place affecting the detection systems based on active detector; this situation is solved using a passive detector. In the case of the Bonner spheres spectrometer the active detector has been substituted by activation detectors, trace detectors or thermoluminescent dosimeters. This spectrometer uses several spheres that are situated one at a time in the measurement point, this way to have the complete measurements group the accelerator should be operated, under the same conditions, so many times like spheres have the spectrometer, this activity can consume a long time and in occasions due to the work load of Linac to complicate the measurement process too. The procedure developed in this work consisted on to situate all the spectrometer spheres at the same time and to make the reading by means of a single shot, to be able to apply this procedure, is necessary that before the measurements two characteristics are evaluated: the cross-talking of the spheres and the symmetry conditions of the neutron field. This method has been applied to determine the photo-neutrons spectrum produced by a lineal accelerator of medical use Varian ix of 15 MV to 100 cm of the isocenter located to 5 cm of depth of a solid water mannequin of 30 x 30 x 15 cm. The spectrum was used to determine the total flow and the environmental dose equivalent. (Author)

  10. Neutronic and burnup studies of accelerator-driven systems dedicated to nuclear waste transmutation

    OpenAIRE

    Tucek, Kamil

    2004-01-01

    Partitioning and transmutation of plutonium, americium, and curium is inevitable if the radiotoxic inventory of spent nuclear fuel is to be reduced by more than a factor of 100. But, admixing minor actinides into the fuel severely degrades system safety parameters, particularly coolant void reactivity, Doppler effect, and (effective) delayed neutron fractions. The incineration process is therefore envisioned to be carried out in dedicated, accelerator-driven sub-critical reactors (ADS). Howev...

  11. Acceptance scan technique for the drift tube linac of the spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, D. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)]. E-mail: jeond@ornl.gov; Stovall, J. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Takeda, H. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Nath, S. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Billen, J. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Young, L. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Kisselev, I. [Institute for Nuclear Research of RAS, Troitsk, Russia (Russian Federation); Shishlo, A. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Aleksandrov, A. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Assadi, S. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Chu, C.M. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Cousineau, S. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Danilov, V. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Galambos, J. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Henderson, S. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Kim, S. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Kravchuk, L. [Institute for Nuclear Research of RAS, Troitsk, Russia (Russian Federation); Tanke, E. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2007-01-01

    For high intensity proton accelerators, it is vital to reduce the machine activation by minimizing the beam loss from many sources. One of such sources is longitudinal mismatch. To minimize a potential mismatch, it is important to set accurately the rf set-point (rf field amplitude and phase) of a high-intensity linac such as the drift tube linac (DTL) of the spallation neutron source. A widely used technique called the acceptance scan was studied extensively and applied successfully to tune the DTL tanks since the initial commissioning. From the acceptance scan one can obtain the longitudinal beam profile at the entrance of each DTL tank. But except tank 1, acceptance scan alone cannot determine the incoming beam energy deviation, leading to small uncertainties in the rf set point.

  12. Neutron sources and its dosimetric characteristics; Fuentes de neutrones y sus caracteristicas dosimetricas

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M.; Mercado S, G.A. [Universidad Autonoma de Zacatecas, A.P. 336, 98000 Zacatecas (Mexico); Gallego D, E.; Lorente F, A. [Universidad Politecnica de Madrid, C/Jose Gutierrez Abascal 2, E-28006 Madrid (Spain)

    2005-07-01

    By means of Monte Carlo methods the spectra of the produced neutrons {sup 252} Cf, {sup 252} Cf/D{sub 2}O, {sup 241} Am Be, {sup 239} Pu Be, {sup 140} La Be, {sup 239} Pu{sup 18}O{sub 2} and {sup 226} Ra Be have been calculated. With the information of the spectrum it was calculated the average energy of the neutrons of each source. By means of the fluence coefficients to dose it was determined, for each one of the studied sources, the fluence factors to dose. The calculated doses were H, H{sup *}(10), H{sub p,sIab} (10, 0{sup 0}), E{sub AP} and E{sub ISO}. During the phase of the calculations the sources were modeled as punctual and their characteristics were determined to 100 cm in the hole. Also, for the case of the sources of {sup 239} Pu Be and {sup 241} Am Be, were carried out calculations modeling the sources with their respective characteristics and the dosimetric properties were determined in a space full with air. The results of this last phase of the calculations were compared with the experimental results obtained for both sources. (Author)

  13. Characteristics of a heavy water photoneutron source in boron neutron capture therapy

    Institute of Scientific and Technical Information of China (English)

    Danial Salehi; Dariush Sardari; M.Salehi Jozani

    2013-01-01

    Bremsstrahlung photon beams produced by medical linear accelerators are currently the most commonly used method of radiation therapy for cancerous tumors.Photons with energies greater than 8-10 MeV potentially generate neutrons through photonuclear interactions in the accelerator's treatment head,patient's body,and treatment room ambient.Electrons impinging on a heavy target generate a cascade shower of bremsstrahlung photons,the energy spectrum of which shows an end point equal to the electron beam energy.By varying the target thickness,an optimum thickness exists for which,at the given electron energy,maximum photon flux is achievable.If a source of high-energy photons i.e.bremsstrahlung,is conveniently directed to a suitable D2O target,a novel approach for production of an acceptable flux of filterable photoneturons for boron neutron capture therapy (BNCT) application is possible.This study consists of two parts.1.Comparison and assessment of deuterium photonuclear cross section data.2.Evaluation of the heavy water photonuclear source.

  14. 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.

  15. 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.

  16. Surviving to tell the tale: Argonne's Intense Pulsed Neutron Source from an ecosystem perspective

    International Nuclear Information System (INIS)

    At first glance the story of the Intense Pulsed Neutron Source (IPNS), an accelerator-driven neutron source for exploring the structure of materials through neutron scattering, seems to be one of puzzling ups and downs. For example, Argonne management, Department of Energy officials, and materials science reviewers continued to offer, then withdraw, votes of confidence even though the middling-sized IPNS produced high-profile research, including work that made the cover of Nature in 1987. In the midst of this period of shifting opinion and impressive research results, some Argonne materials scientists were unenthusiastic, members of the laboratory's energy physics group were key supporters, and materials scientists at another laboratory provided, almost fortuitously, a new lease on life. What forces shaped the puzzling life cycle of the IPNS? And what role - if any - did the moderate price tag and the development of scientific and technological ideas play in the course it took? To answer these questions this paper looks to an ecosystem metaphor for inspiration, exploring how opinions, ideas, and machinery emerged from the interrelated resource economies of Argonne, the DOE, and the materials science community by way of a tangled web of shifting group interactions. The paper will conclude with reflections about what the resulting focus on relationality explains about the IPNS story as well as the underlying dynamic that animates knowledge production at U.S. national laboratories.

  17. The influence of external source intensity in accelerator/target/blanket system on conversion ratio and fuel cycle

    Science.gov (United States)

    Kochurov, Boris P.

    1995-09-01

    The analysis of neutron balance relation for a subcritical system with external source shows that a high ratio of neutron utilization (conversion ratio, breeding ratio) much exceeding similar values for nuclear reactors (both thermal or fast spectrum) is reachable in accelerator/target/blanket system with high external neutron source intensity. An accelerator/target/blanket systems with thermal power in blanket about 1850 Mwt and operating during 30 years have been investigated. Continual feed up by plutonium (fissile material) and Tc-99 (transmuted material) was assumed. Accelerator beam intensity differed 6.3 times (16 mA-Case 1, and 100 mA-Case 2). Conversion ratio (CR) was defined as the ratio of Tc-99 nuclei transmuted to the number of Pu nuclei consumed. The results for two cases are as follows: Case 1Case 2CR 0.77 1.66N(LWR) 8.6 19.1Power MWt(el) 512 225 where N(LWR)-number of LWRs(3000 MWt(th)) from which yearly discharge of Tc-99 is transmuted during 30 years. High value of conversion ratio considerably exceeding 1 (CR=1.66) was obtained in the system with high source intensity as compared with low source system (CR=0.77). Net output of electric power of high source intensity system is about twice lower due to consumption of electric power for accelerator feed up. The loss of energy for Tc-99 transmutation is estimated as 40 Mev(el)/nuclei. Yet high conversion ratio (or breeding ratio) achievable in electronuclear installations with high intensity of external source can effectively be used to close fuel cycle (including incineration of wastes) or to develop growing nuclear power production system.

  18. Modelling of an imaging beamline at the ISIS pulsed neutron source

    OpenAIRE

    Burca, G.; Kockelmann, W.; James, J A; Fitzpatrick, M. E.

    2013-01-01

    A combined neutron imaging and neutron diffraction facility, IMAT, is currently being built at the pulsed neutron spallation source ISIS in the U.K. A supermirror neutron guide is required to combine imaging and diffraction modes at the sample position in order to obtain suitable time of flight resolutions for energy selective imaging and diffraction experiments. IMAT will make use of a straight neutron guide and we consider here the optimization of the supermirror guide dimensions and charac...

  19. Installation and performance tests of KUR cold neutron source, 2

    International Nuclear Information System (INIS)

    Our cold neutron source is operated by a closed-indirect cooling loop. The hydrogen cryogenic system of the KUR-CNS has been shown a self-regulating characteristic to the thermal disturbances smaller than 30 % of the maximum heat load, which is measured 300 W at 25 K. This power is used to release a nuclear heating. This self-regulating characteristic was confirmed from the amplitude vs frequency curve, so called Bode's diagram, which showed the first order time lag. Due to this property, the liquid level in the moderator cell has been kept almost constant under 5 MW power of the reactor. The measurements of neutron counting rates across the central level of the moderator cell showed that the demanded liquid content was stored in the cell. (author)

  20. Modeling of water radiolysis at spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Daemen, L.L.; Kanner, G.S.; Lillard, R.S.; Butt, D.P.; Brun, T.O.; Sommer, W.F.

    1998-12-01

    In spallation neutron sources neutrons are produced when a beam of high-energy particles (e.g., 1 GeV protons) collides with a (water-cooled) heavy metal target such as tungsten. The resulting spallation reactions produce a complex radiation environment (which differs from typical conditions at fission and fusion reactors) leading to the radiolysis of water molecules. Most water radiolysis products are short-lived but extremely reactive. When formed in the vicinity of the target surface they can react with metal atoms, thereby contributing to target corrosion. The authors will describe the results of calculations and experiments performed at Los Alamos to determine the impact on target corrosion of water radiolysis in the spallation radiation environment. The computational methodology relies on the use of the Los Alamos radiation transport code, LAHET, to determine the radiation environment, and the AEA code, FACSIMILE, to model reaction-diffusion processes.