Science.gov

Sample records for radio-isotopic neutron sources

  1. Neutron imaging of radioactive sources

    NASA Astrophysics Data System (ADS)

    Hameed, F.; Karimzadeh, S.; Zawisky, M.

    2008-08-01

    Isotopic neutron sources have been available for more than six decades. At the Atomic Institute in Vienna, operating a 250 kW TRIGA reactor, different neutron sources are in use for instrument calibration and fast neutron applications but we have only little information about their construction and densities. The knowledge of source design is essential for a complete MCNP5 modeling of the experiments. Neutron radiography (NR) and neutron tomography (NT) are the best choices for the non-destructive inspection of the source geometry and homogeneity. From the transmission analysis we gain information about the shielding components and the densities of the radio-isotopes in the cores. Three neutron sources, based on (alpha, n) reaction, have been investigated, two 239PuBe sources and one 241AmBe source. In the NR images the internal structure was clearly revealed using high-resolving scintillation and imaging plate detectors. In one source tablet a crack was detected which causes asymmetric neutron emission. The tomography inspection of strong absorbing materials is more challenging due to the low beam intensity of 1.3x105 n/cm2s at our NT instrument, and due to the beam hardening effect which requires an extension of reconstruction software. The tomographic inspection of a PuBe neutron source and appropriate measures for background and beam hardening correction are presented.

  2. Neutron sources and applications

    SciTech Connect

    Price, D.L.; Rush, J.J.

    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.

  3. Ultrashort pulsed neutron source.

    PubMed

    Pomerantz, I; McCary, E; Meadows, A R; Arefiev, A; Bernstein, A C; Chester, C; Cortez, J; Donovan, M E; Dyer, G; Gaul, E W; Hamilton, D; Kuk, D; Lestrade, A C; Wang, C; Ditmire, T; Hegelich, B M

    2014-10-31

    We report on a novel compact laser-driven neutron source with an unprecedented short pulse duration (<50??ps) and high peak flux (>10(18)??n/cm(2)/s), an order of magnitude higher than any existing source. In our experiments, high-energy electron jets are generated from thin (<3???m) plastic targets irradiated by a petawatt laser. These intense electron beams are employed to generate neutrons from a metal converter. Our method opens venues for enhancing neutron radiography contrast and for creating astrophysical conditions of heavy element synthesis in the laboratory. PMID:25396373

  4. Coded source neutron imaging

    SciTech Connect

    Bingham, Philip R; Santos-Villalobos, Hector J

    2011-01-01

    Coded aperture techniques have been applied to neutron radiography to address limitations in neutron flux and resolution of neutron detectors in a system labeled coded source imaging (CSI). By coding the neutron source, a magnified imaging system is designed with small spot size aperture holes (10 and 100 m) for improved resolution beyond the detector limits and with many holes in the aperture (50% open) to account for flux losses due to the small pinhole size. An introduction to neutron radiography and coded aperture imaging is presented. A system design is developed for a CSI system with a development of equations for limitations on the system based on the coded image requirements and the neutron source characteristics of size and divergence. Simulation has been applied to the design using McStas to provide qualitative measures of performance with simulations of pinhole array objects followed by a quantitative measure through simulation of a tilted edge and calculation of the modulation transfer function (MTF) from the line spread function. MTF results for both 100um and 10um aperture hole diameters show resolutions matching the hole diameters.

  5. Optimization of neutron source

    SciTech Connect

    Hooper, E.B.

    1993-11-09

    I consider here the optimization of the two component neutron source, allowing beam species and energy to vary. A simple model is developed, based on the earlier publications, that permits the optimum to be obtained simply. The two component plasma, with one species of hot ion (D{sup +} or T{sup +}) and the complementary species of cold ion, is easy to analyze in the case of a spatially uniform cold plasma, as to good approximation the total number of hot ions is important but not their spatial distribution. Consequently, the optimization can ignore spatial effects. The problem of a plasma with both types of hot ions and cold ions is rather more difficult, as the neutron production by hot-hot interactions is sensitive to their spatial distributions. Consequently, consideration of this problem will be delayed to a future memorandum. The basic model is that used in the published articles on the two-component, beam-plasma mirror source. I integrate the Fokker-Planck equation analytically, obtaining good agreement with previous numerical results. This simplifies the optimization, by providing a functional form for the neutron production. The primary result is expressed in terms of the power efficiency: watts of neutrons/watts of primary power. The latter includes the positive ion neutralization efficiency. At 150 keV, the present model obtains an efficiency of 0.66%, compared with 0.53% of the earlier calculation.

  6. ACCELERATOR BASED CONTINUOUS NEUTRON SOURCE.

    SciTech Connect

    SHAPIRO,S.M.; RUGGIERO,A.G.; LUDEWIG,H.

    2003-03-25

    Until the last decade, most neutron experiments have been performed at steady-state, reactor-based sources. Recently, however, pulsed spallation sources have been shown to be very useful in a wide range of neutron studies. A major review of neutron sources in the US was conducted by a committee chaired by Nobel laureate Prof. W. Kohn: ''Neutron Sources for America's Future-BESAC Panel on Neutron Sources 1/93''. This distinguished panel concluded that steady state and pulsed sources are complementary and that the nation has need for both to maintain a balanced neutron research program. The report recommended that both a new reactor and a spallation source be built. This complementarity is recognized worldwide. The conclusion of this report is that a new continuous neutron source is needed for the second decade of the 20 year plan to replace aging US research reactors and close the US neutron gap. it is based on spallation production of neutrons using a high power continuous superconducting linac to generate protons impinging on a heavy metal target. There do not appear to be any major technical challenges to the building of such a facility since a continuous spallation source has been operating in Switzerland for several years.

  7. Accelerator based epithermal neutron source

    NASA Astrophysics Data System (ADS)

    Taskaev, S. Yu.

    2015-11-01

    We review the current status of the development of accelerator sources of epithermal neutrons for boron neutron capture therapy (BNCT), a promising method of malignant tumor treatment. Particular attention is given to the source of epithermal neutrons on the basis of a new type of charged particle accelerator: tandem accelerator with vacuum insulation and lithium neutron-producing target. It is also shown that the accelerator with specialized targets makes it possible to generate fast and monoenergetic neutrons, resonance and monoenergetic gamma-rays, alpha-particles, and positrons.

  8. RIKEN Radio Isotope Beam Factory: Japanese Flagship for Nuclear Science

    NASA Astrophysics Data System (ADS)

    En'yo, Hideto

    2015-11-01

    Recent activities at the RIKEN Radio Isotope Beam Factory (RIBF) are reported together with its history and future prospects. RIBF is the Japanese flagship for nuclear science, and at this moment is the world flagship machine.

  9. Research on fusion neutron sources

    NASA Astrophysics Data System (ADS)

    Gryaznevich, M. P.

    2012-06-01

    The use of fusion devices as powerful neutron sources has been discussed for decades. Whereas the successful route to a commercial fusion power reactor demands steady state stable operation combined with the high efficiency required to make electricity production economic, the alternative approach to advancing the use of fusion is free of many of complications connected with the requirements for economic power generation and uses the already achieved knowledge of Fusion physics and developed Fusion technologies. "Fusion for Neutrons" (F4N), has now been re-visited, inspired by recent progress achieved on comparably compact fusion devices, based on the Spherical Tokamak (ST) concept. Freed from the requirement to produce much more electricity than used to drive it, a fusion neutron source could be efficiently used for many commercial applications, and also to support the goal of producing energy by nuclear power. The possibility to use a small or medium size ST as a powerful or intense steady-state fusion neutron source (FNS) is discussed in this paper in comparison with the use of traditional high aspect ratio tokamaks. An overview of various conceptual designs of compact fusion neutron sources based on the ST concept is given and they are compared with a recently proposed Super Compact Fusion Neutron Source (SCFNS), with major radius as low as 0.5 metres but still able to produce several MW of neutrons in a steady-state regime.

  10. Research on fusion neutron sources

    SciTech Connect

    Gryaznevich, M. P.

    2012-06-19

    The use of fusion devices as powerful neutron sources has been discussed for decades. Whereas the successful route to a commercial fusion power reactor demands steady state stable operation combined with the high efficiency required to make electricity production economic, the alternative approach to advancing the use of fusion is free of many of complications connected with the requirements for economic power generation and uses the already achieved knowledge of Fusion physics and developed Fusion technologies. 'Fusion for Neutrons' (F4N), has now been re-visited, inspired by recent progress achieved on comparably compact fusion devices, based on the Spherical Tokamak (ST) concept. Freed from the requirement to produce much more electricity than used to drive it, a fusion neutron source could be efficiently used for many commercial applications, and also to support the goal of producing energy by nuclear power. The possibility to use a small or medium size ST as a powerful or intense steady-state fusion neutron source (FNS) is discussed in this paper in comparison with the use of traditional high aspect ratio tokamaks. An overview of various conceptual designs of compact fusion neutron sources based on the ST concept is given and they are compared with a recently proposed Super Compact Fusion Neutron Source (SCFNS), with major radius as low as 0.5 metres but still able to produce several MW of neutrons in a steady-state regime.

  11. Materials for spallation neutron sources

    SciTech Connect

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

    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.

  12. New neutron physics using spallation sources

    SciTech Connect

    Bowman, C.D.

    1988-01-01

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

  13. Accelerator neutron source for boron neutron capture therapy

    SciTech Connect

    Wang, C.K.; Blue, T.E.; Blue, J.W.; Gahbauer, R.A.

    1987-01-01

    If boron neutron capture therapy (BNCT) is to be widely used to treat patients with brain tumors, then a hospital-based neutron source must be developed. Accelerator neutron sources for BNCT have been proposed as alternatives to nuclear reactor beams. The ideal neutron source for BNCT is a monoenergetic neutron beam with a neutron energy that is above thermal energies but below approx. 10 keV. The optimum neutron energy is currently being studied. The purpose of this paper is to report the results of a Monte Carlo analysis of the performance of an accelerator neutron source for the treatment of brain tumors by BNCT. The proton beam is identical. Thicknesses of moderators are identified that yield neutron energy spectra which produce within a head phantom distributions of absorbed dose approaching the distributions that would be attained with the above-mentioned ideal spectra.

  14. Neutron-emission measurements at a white neutron source

    SciTech Connect

    Haight, Robert C

    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. Compact ion source neutron generator

    DOEpatents

    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.

  16. A Trial to Natural Neutron Radiography

    NASA Astrophysics Data System (ADS)

    Taniguchi, Ryoichi; Ito, Norio

    Neutron radiography system without the use of artificial neutron source has been developed. It uses only natural neutrons which exist continuously in any place. The system consists of a high sensitivity neutron imaging device and neutron moderator. The imaging device used was a 2-dimensional photon counter system which has been developing so far for high sensitivity neutron imaging. However, further improvement of neutron sensitivity and reduction of?-ray response is no doubt indispensable, while?-rays originated by cosmic rays and environmental radio isotopes also exist with the flux in several orders of magnitude large compared with that of the neutrons. The environmental neutrons are originated by cosmic ray. The intensity of natural neutrons is changed with the environmental conditions. Interestingly, the neutrons were observed to increase considerably with the condition near the massive iron blocks. The phenomenon is useful for our purpose, while the main object of the natural neutron imaging system is the field inspection of large iron structures.

  17. Californium-252 Neutron Sources for Medical Applications

    SciTech Connect

    Boulogne, A.R.

    2001-08-29

    Californium-252 neutron sources are being prepared to investigate the value of this radionuclide in diagnosing and treating diseases. A source resembling a cell-loaded radium needle was developed for neutron therapy. Since therapy needles are normally implanted in the body, very conservative design criteria were established to prevent leakage of radioactive. Methods are being developed to prepare very intense californium sources that could be used eventually for neutron radiography and for diagnosis by neutron activation analysis. This paper discusses these methods.

  18. Fission neutron source in Rome

    NASA Astrophysics Data System (ADS)

    Coppola, Mario; Di Majo, V.; Ingrao, G.; Rebessi, S.; Testa, A.

    1997-02-01

    A fission neutron source is operating in Rome at the ENEA Casaccia Research Center since 1971, consisting of a low power fast reactor named RSV-Tapiro. it is employed for a variety of experiments, including dosimetry, material testing, radiation protection and biology. In particular, application to experimental radiobiology includes studies of the biological action of neutrons in the whole-body irradiated animal, or in specialized systems in vivo or in vitro. For his purpose a vertical irradiation facility was originally constructed. Recently, a new horizontal irradiation facility has been designed to allow the exposure of larger samples or larger sample batches at one time. Dosimetry at the sample irradiation positions is routinely carried out by the conventional method of using two ion chambers. This physical dosimetry has recently been compared with the results of biological dosimetry based on the detection of chromosomal aberrations in peripheral blood human lymphocytes irradiated in vitro. A characterization of the radiation quality in the two configurations has been carried out by tissue equivalent proportional counter microdosimetry measurements. Information about the main characteristics of the reactor and the two irradiation facilities is provided and relevant results of the various measurements are summarized. Radiobiological results obtained using this neutron source are also briefly outlined.

  19. Development of Neutron Color Image Intensifier for Pulsed Neutron Source

    NASA Astrophysics Data System (ADS)

    Nittoh, Koichi; Konagai, Chikara; Yahagi, Mitsuru; Kiyanagi, Yoshiaki; Kamiyama, Takashi

    We have been developing neutron color image intensifiers (hereafter abbreviated as NCIIs) for static neutron sources. With the recent progress of high power pulsed neutron sources, needs for energy selective neutron imaging are increasing. To fulfil suchrequirements, we have newly developed NCIIs having a high-speed blanking (gating) circuit and an output phosphor withshorter decay time. By combining these functions with a selection of input phosphor, measuring neutron energy ranges could beprecisely selectable between cold and epithermal region, which extends the NCII utilization area to pulsed facilities.

  20. THE SPALLATION NEUTRON SOURCE PROJECT - PHYSICAL CHALLENGES.

    SciTech Connect

    WEI,J.

    2002-06-03

    The Spallation Neutron Source (SNS) is designed to reach an average proton beam power of 1.4 MW for pulsed neutron production. This paper summarizes design aspects and physical challenges to the project.

  1. Ion sources for sealed neutron tubes

    SciTech Connect

    Burns, E.J.T.; Bischoff, G.C.

    1996-11-01

    Fast and thermal neutron activation analysis with sealed neutron generators has been used to detect oil (oil logging), hazardous waste, fissile material, explosives, and contraband (drugs). Sealed neutron generators, used in the above applications, must be small and portable, have good electrical efficiency and long life. The ion sources used in the sealed neutron tubes require high gas utilization efficiencies or low pressure operation with high ionization efficiencies. In this paper, the authors compare a number of gas ion sources that can be used in sealed neutron tubes. The characteristics of the most popular ion source, the axial Penning discharge will be discussed as part of the zetatron neutron generator. Other sources to be discussed include the SAMIS source and RF ion source.

  2. Switchable radioactive neutron source device

    DOEpatents

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

    1987-11-06

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

  3. Neutron sources: present practice and future potential

    SciTech Connect

    Cierjacks, S.; Smith, A.B.

    1988-01-01

    The present capability and future potential of accelerator-based monoenergetic and white neutron sources are outlined in the context of fundamental and applied neutron-nuclear research. The neutron energy range extends from thermal to 500+ MeV, and the time domain from steady-state to pico-second pulsed sources. Accelerator technology is summarized, including the production of intense light-ion, heavy-ion and electron beams. Target capabilities are discussed with attention to neutron-production efficiency and power-handling capabilities. The status of underlying neutron-producing reactions is summarized. The present and future use of neutron sources in: (i) fundamental neutron-nuclear research, (ii) nuclear-data acquisition, (iii) materials-damage studies, (iv) engineering test, and (v) biomedical applications are discussed. Emphasis is given to current status, near-term advances well within current technology, and to long-range projections.

  4. Neutron Sources for Standard-Based Testing

    SciTech Connect

    Radev, Radoslav; McLean, Thomas

    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.

  5. Spallation Neutron Source reaches megawatt power

    SciTech Connect

    Dr. William F. Brinkman

    2009-09-30

    The Department of Energy's Spallation Neutron Source (SNS), already the world's most powerful facility for pulsed neutron scattering science, is now the first pulsed spallation neutron source to break the one-megawatt barrier. "Advances in the materials sciences are fundamental to the development of clean and sustainable energy technologies. In reaching this milestone of operating power, the Spallation Neutron Source is providing scientists with an unmatched resource for unlocking the secrets of materials at the molecular level," said Dr. William F. Brinkman, Director of DOE's Office of Science.

  6. Spallation Neutron Source reaches megawatt power

    ScienceCinema

    Dr. William F. Brinkman

    2010-01-08

    The Department of Energy's Spallation Neutron Source (SNS), already the world's most powerful facility for pulsed neutron scattering science, is now the first pulsed spallation neutron source to break the one-megawatt barrier. "Advances in the materials sciences are fundamental to the development of clean and sustainable energy technologies. In reaching this milestone of operating power, the Spallation Neutron Source is providing scientists with an unmatched resource for unlocking the secrets of materials at the molecular level," said Dr. William F. Brinkman, Director of DOE's Office of Science.

  7. Neutron producing reactions in PuBe neutron sources

    NASA Astrophysics Data System (ADS)

    Bagi, János; Lakosi, László; Nguyen, Cong Tam

    2016-01-01

    There are a plenty of out-of-use plutonium-beryllium neutron sources in Eastern Europe presenting both nuclear safeguards and security issues. Typically, their actual Pu content is not known. In the last couple of years different non-destructive methods were developed for their characterization. For such methods detailed knowledge of the nuclear reactions taking place within the source is necessary. In this paper we investigate the role of the neutron producing reactions, their contribution to the neutron yield and their dependence on the properties of the source.

  8. Neutron fan beam source for neutron radiography purpose

    SciTech Connect

    Le Tourneur, P.; Bach, P.; Dance, W. E.

    1999-06-10

    The development of the DIANE neutron radiography system included a sealed-tube neutron generator for this purpose and the optimization of the system's neutron beam quality in terms of divergence and useful thermal neutron yield for each 14-MeV neutron produced. Following this development, the concept of a DIANE fan beam source is herewith introduced. The goal which drives this design is one of economy: by simply increasing the aperture dimension of a conventional DIANE beam in one plane of its collimator axis to a small-angle, fan-shaped output, the useful beam area for neutron radiography would be substantially increased. Thus with the same source, the throughput, or number of objects under examination at any given time, would be augmented significantly. Presented here are the design of this thermal neutron source and the initial Monte Carlo calculations. Taking into account the experience with the conventional DIANE neutron radiography system, these result are discussed and the potential of and interest in such a fan-beam source are explored.

  9. Nested Focusing Optics for Compact Neutron Sources

    NASA Technical Reports Server (NTRS)

    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.

  10. Cyclotron-based neutron source for BNCT

    SciTech Connect

    Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K.; Tanaka, H.; Sakurai, Y.; Maruhashi, A.

    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.

  11. Cyclotron-based neutron source for BNCT

    NASA Astrophysics Data System (ADS)

    Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K.; Tanaka, H.; Sakurai, Y.; Maruhashi, A.

    2013-04-01

    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 & 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 1.8×109 neutrons/cm2/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 10B-p-Borono-phenylalanine. Clinical trials of malignant brain tumors will be started in this year.

  12. International workshop on cold neutron sources

    SciTech Connect

    Russell, G.J.; West, C.D. )

    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.

  13. Observation of Neutron Skyshine from an Accelerator Based Neutron Source

    NASA Astrophysics Data System (ADS)

    Franklyn, C. B.

    2011-12-01

    A key feature of neutron based interrogation systems is the need for adequate provision of shielding around the facility. Accelerator facilities adapted for fast neutron generation are not necessarily suitably equipped to ensure complete containment of the vast quantity of neutrons generated, typically >1011 n?s-1. Simulating the neutron leakage from a facility is not a simple exercise since the energy and directional distribution can only be approximated. Although adequate horizontal, planar shielding provision is made for a neutron generator facility, it is sometimes the case that vertical shielding is minimized, due to structural and economic constraints. It is further justified by assuming the atmosphere above a facility functions as an adequate radiation shield. It has become apparent that multiple neutron scattering within the atmosphere can result in a measurable dose of neutrons reaching ground level some distance from a facility, an effect commonly known as skyshine. This paper describes a neutron detection system developed to monitor neutrons detected several hundred metres from a neutron source due to the effect of skyshine.

  14. Observation of Neutron Skyshine from an Accelerator Based Neutron Source

    SciTech Connect

    Franklyn, C. B.

    2011-12-13

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

  15. 10 CFR 39.55 - Tritium neutron generator target sources.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Tritium neutron generator target sources. 39.55 ...LOGGING Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target source,...

  16. 10 CFR 39.55 - Tritium neutron generator target sources.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Tritium neutron generator target sources. 39.55 ...LOGGING Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target source,...

  17. 10 CFR 39.55 - Tritium neutron generator target sources.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Tritium neutron generator target sources. 39.55 ...LOGGING Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target source,...

  18. 10 CFR 39.55 - Tritium neutron generator target sources.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Tritium neutron generator target sources. 39.55 ...LOGGING Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target source,...

  19. 10 CFR 39.55 - Tritium neutron generator target sources.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Tritium neutron generator target sources. 39.55 ...LOGGING Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target source,...

  20. Unconventional neutron sources for oil well logging

    NASA Astrophysics Data System (ADS)

    Frankle, C. M.; Dale, G. E.

    2013-09-01

    Americium-Beryllium (AmBe) radiological neutron sources have been widely used in the petroleum industry for well logging purposes. There is strong desire on the part of various governmental and regulatory bodies to find alternate sources due to the high activity and small size of AmBe sources. Other neutron sources are available, both radiological (252Cf) and electronic accelerator driven (D-D and D-T). All of these, however, have substantially different neutron energy spectra from AmBe and thus cause significantly different responses in well logging tools. We report on simulations performed using unconventional sources and techniques to attempt to better replicate the porosity and carbon/oxygen ratio responses a well logging tool would see from AmBe neutrons. The AmBe response of these two types of tools is compared to the response from 252Cf, D-D, D-T, filtered D-T, and T-T sources.

  1. Advanced Neutron Source (ANS) Project progress report

    SciTech Connect

    McBee, M.R.; Chance, C.M. ); Selby, D.L.; Harrington, R.M.; Peretz, F.J. )

    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.

  2. Modulating the Neutron Flux from a Mirror Neutron Source

    SciTech Connect

    Ryutov, D D

    2011-09-01

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

  3. Californium-252: A New Isotopic Source for Neutron Radiography

    SciTech Connect

    Reinig, W.C.

    2001-08-29

    This report discusses a new isotopic source for neutron radiography, Californium-252. Nuclear reactors are the usual source of neutrons for radiography, primarily because of their intense neutron beams. If neutron radiography is to have widespread use, intense transportable neutron sources are required that can be used in plants, in laboratories and in the field.

  4. Cryogenic hydrogen circulation system of neutron source

    SciTech Connect

    Qiu, Y. N.; Hu, Z. J.; Wu, J. H.; Li, Q.; Zhang, Y.; Zhang, P.; Wang, G. P.

    2014-01-29

    Cold neutron sources of reactors and spallation neutron sources are classic high flux neutron sources in operation all over the world. Cryogenic fluids such as supercritical or supercooled hydrogen are commonly selected as a moderator to absorb the nuclear heating from proton beams. By comparing supercritical hydrogen circulation systems and supercooled hydrogen circulation systems, the merits and drawbacks in both systems are summarized. When supercritical hydrogen circulates as the moderator, severe pressure fluctuations caused by temperature changes will occur. The pressure control system used to balance the system pressure, which consists of a heater as an active controller for thermal compensation and an accumulator as a passive volume controller, is preliminarily studied. The results may provide guidelines for design and operation of other cryogenic hydrogen system for neutron sources under construction.

  5. High Brightness Neutron Source for Radiography

    SciTech Connect

    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 of yield of two orders of magnitude. The first fast neutron radiographic images were obtained using neutron cameras and a new fast neutron generator. These early images demonstrated the feasibility of using fast neutrons for imaging and penetrating thick objects of high density and imaging. Fast neutrons can be used to image low atomic number materials (e.g. plastics, explosives, lubricants and ceramics) that are shielded by high density materials (e.g. lead, tungsten and uranium). Fast neutron radiography could be used as a means to screen weapons for flaws and chemical stability. X-ray radiography can not easily do this. Fast neutron imaging is technically difficult and, consequently, a completely undeveloped market. Two of the generators were designed to have small source size and high brightness, ideal for fast-neutron imaging. With these generators we successfully used two fast neutron cameras: one developed by us, and another developed by a collaborator, Commonwealth Scientific and Industrial Research Organization, CSIRO. We have successfully used these cameras to obtain low resolution images of various objects such as pipe fittings filled with water and other mechanical objects. Higher resolution and contrast images are expected by decreasing the source size and increasing generator yield.

  6. Spallation neutron source target station issues

    SciTech Connect

    Gabriel, T.A.; Barnes, J.N.; Charlton, L.A.

    1996-10-01

    In many areas of physics, materials and nuclear engineering, it is extremely valuable to have a very intense source of neutrons so that the structure and function of materials can be studied. One facility proposed for this purpose is the National Spallation Neutron Source (NSNS). This facility will consist of two parts: (1) a high-energy ({approximately}1 GeV) and high powered ({approximately} 1 MW) proton accelerator, and (2) a target station which converts the protons to low-energy ({le} 2 eV) neutrons and delivers them to the neutron scattering instruments. This paper deals with the second part, i.e., the design and development of the NSNS target station and the scientifically challenging issues. Many scientific and technical disciplines are required to produce a successful target station. These include engineering, remote handling, neutronics, materials, thermal hydraulics, and instrumentation. Some of these areas will be discussed.

  7. An Accelerator Neutron Source for BNCT

    SciTech Connect

    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.

  8. Phenomenological calculations of shielding spallation neutron sources

    NASA Astrophysics Data System (ADS)

    Fragopoulou, M.; Zamani, M.

    2013-06-01

    The high level of radiation generated by a spallation source requires the design of an appropriate shielding to surround the source in order to fulfill radiation protection standards. A calculation of the spallation neutron attenuation is presented for various shielding materials, using a phenomenological model, based on the Moyer model. In the first step of the calculation, the interaction length of neutrons for each neutron energy and shielding material was estimated using inelastic cross-sections. In the second step the calculation deals with the attenuation of the neutron flux applying the Moyer model, for each material and neutron energy region. The transmission factors were calculated and compared with experimental data collected from the "Gamma-2" and the "E+T" projects running in JINR (Dubna, Russia). The results of the present work were also compared to the data obtained by different Monte Carlo codes such as MORSE, MCNPX, MARS14 and LAHET.

  9. A telescope for monitoring fast neutron sources

    NASA Astrophysics Data System (ADS)

    Ban, G.; Fontbonne, J. M.; Lecolley, F. R.; Lecolley, J. F.; Lecouey, J. L.; Marie, N.; Steckmeyer, J. C.; Billebaud, A.; Brissot, R.; Le Brun, C.; Liatard, E.

    2007-07-01

    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.

  10. Neutron science opportunities at pulsed spallation neutron sources

    SciTech Connect

    Carpenter, J.M.

    1996-12-31

    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.

  11. Advanced Neutron Source: The users' perspective

    SciTech Connect

    Peretz, F.J.

    1990-01-01

    User experiments will cover fields such as activation analysis of pollutants, irradiation of materials for the fusion program, and neutron scattering studies of materials as diverse as viruses, aerospace composites, and superconductors. Production capabilities must also be provided for the production of isotopes, especially of transuranic elements. The different ways in which these research areas and their required infrastructure influence the design of the Advanced Neutron Source will be the subject of this paper.

  12. Iterative Reconstruction of Coded Source Neutron Radiographs

    SciTech Connect

    Santos-Villalobos, Hector J; Bingham, Philip R; Gregor, Jens

    2012-01-01

    Use of a coded source facilitates high-resolution neutron imaging but requires that the radiographic data be deconvolved. In this paper, we compare direct deconvolution with two different iterative algorithms, namely, one based on direct deconvolution embedded in an MLE-like framework and one based on a geometric model of the neutron beam and a least squares formulation of the inverse imaging problem.

  13. 10 CFR 39.55 - Tritium neutron generator target sources.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Tritium neutron generator target sources. 39.55 Section 39... Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target...) Use of a tritium neutron generator target source, containing quantities exceeding 1,110 GBg or in...

  14. 10 CFR 39.55 - Tritium neutron generator target sources.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Tritium neutron generator target sources. 39.55 Section 39... Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target...) Use of a tritium neutron generator target source, containing quantities exceeding 1,110 GBg or in...

  15. 10 CFR 39.55 - Tritium neutron generator target sources.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Tritium neutron generator target sources. 39.55 Section 39... Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target...) Use of a tritium neutron generator target source, containing quantities exceeding 1,110 GBg or in...

  16. 10 CFR 39.55 - Tritium neutron generator target sources.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Tritium neutron generator target sources. 39.55 Section 39... Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target...) Use of a tritium neutron generator target source, containing quantities exceeding 1,110 GBg or in...

  17. 10 CFR 39.55 - Tritium neutron generator target sources.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Tritium neutron generator target sources. 39.55 Section 39... Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target...) Use of a tritium neutron generator target source, containing quantities exceeding 1,110 GBg or in...

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

    EPA Science Inventory

    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...

  19. Iterative Reconstruction of Coded Source Neutron Radiographs

    SciTech Connect

    Santos-Villalobos, Hector J; Bingham, Philip R; Gregor, Jens

    2013-01-01

    Use of a coded source facilitates high-resolution neutron imaging through magnifications but requires that the radiographic data be deconvolved. A comparison of direct deconvolution with two different iterative algorithms has been performed. One iterative algorithm is based on a maximum likelihood estimation (MLE)-like framework and the second is based on a geometric model of the neutron beam within a least squares formulation of the inverse imaging problem. Simulated data for both uniform and Gaussian shaped source distributions was used for testing to understand the impact of non-uniformities present in neutron beam distributions on the reconstructed images. Results indicate that the model based reconstruction method will match resolution and improve on contrast over convolution methods in the presence of non-uniform sources. Additionally, the model based iterative algorithm provides direct calculation of quantitative transmission values while the convolution based methods must be normalized base on known values.

  20. International Spallation Ultracold Neutron Source

    E-print Network

    Martin, Jeff

    extraction, improved guide technology, etc. Item Cost Funding Source UCN cryostat system $4M Japanese Moderator design $0.675M Manitoba + Acsion Industries Total $10.9M #12;iSUN timeline 20078: UCN source supported by TRIUMF committees, included in plan for TRIUMF 2008: CFI NIF proposal submitted ­ Inkind

  1. Enrico Fermi's Discovery of Neutron-Induced Artificial Radioactivity: Neutrons and Neutron Sources

    NASA Astrophysics Data System (ADS)

    Guerra, Francesco; Leone, Matteo; Robotti, Nadia

    2006-09-01

    We reconstruct and analyze the path leading from James Chadwick’s discovery of the neutron in February 1932 through Frédéric Joliot and Irène Curie’s discovery of artificial radioactivity in January 1934 to Enrico Fermi’s discovery of neutron-induced artificial radioactivity in March 1934. We show, in particular, that Fermi’s innovative construction and use of radon-beryllium neutron sources permitted him to make his discovery.

  2. Secondary electron ion source neutron generator

    DOEpatents

    Brainard, John P. (Albuquerque, NM); McCollister, Daryl R. (Albuquerque, NM)

    1998-01-01

    A neutron generator employing an electron emitter, an ion source bombarded by the electrons from the electron emitter, a plasma containment zone, and a target situated between the plasma containment zone and the electron emitter. The target contains occluded deuterium, tritium, or a mixture thereof

  3. Secondary electron ion source neutron generator

    DOEpatents

    Brainard, J.P.; McCollister, D.R.

    1998-04-28

    A neutron generator employing an electron emitter, an ion source bombarded by the electrons from the electron emitter, a plasma containment zone, and a target situated between the plasma containment zone and the electron emitter is disclosed. The target contains occluded deuterium, tritium, or a mixture thereof. 4 figs.

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

    NASA Astrophysics Data System (ADS)

    Gamage, K. A. A.; Taylor, G. C.

    2015-07-01

    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.

  5. HIGH FLUENCE NEUTRON SOURCE FOR NONDESTRUCTIVE CHARACTERIZATION OF NUCLEAR WASTE

    EPA Science Inventory

    We propose to research the basic plasma physics necessary to develop a high fluence neutron source based on the inertial electrostatically confined (IEC) plasma. An intense neutron source directly addresses the capability to characterize nuclear materials under difficult measurem...

  6. Portable, high intensity isotopic neutron source provides increased experimental accuracy

    NASA Technical Reports Server (NTRS)

    Mohr, W. C.; Stewart, D. C.; Wahlgren, M. A.

    1968-01-01

    Small portable, high intensity isotopic neutron source combines twelve curium-americium beryllium sources. This high intensity of neutrons, with a flux which slowly decreases at a known rate, provides for increased experimental accuracy.

  7. Spallation neutron source saddle antenna H- ion source project.

    PubMed

    Dudnikov, Vadim; Johnson, Rolland P; Dudnikova, Galina; Stockli, Martin; Welton, Robert

    2010-02-01

    In this project we are developing an H(-) source which will synthesize the most important developments in the field of negative ion sources to provide high current, high brightness, good lifetime, high reliability, and high power efficiency. We describe two planned modifications to the present spallation neutron source external antenna source in order to increase the plasma density near the output aperture: (1) replacing the present 2 MHz plasma-forming solenoid antenna with a 13 MHz saddle-type antenna and (2) replacing the permanent multicusp magnetic system with a weaker electromagnet. PMID:20192379

  8. Spallation neutron source and other high intensity froton sources

    SciTech Connect

    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.

  9. Physics design of a cold neutron source for KIPT neutron source facility.

    SciTech Connect

    Zhong, Z.; Gohar, Y.; Kellogg, R.; Nuclear Engineering Division

    2009-02-17

    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 a neutron source facility. It is based on the use of an electron accelerator driven subcritical (ADS) facility with low enriched uranium fuel, using the existing electron accelerators at KIPT of Ukraine [1]. The neutron source of the subcritical assembly is generated from the interaction of 100-KW electron beam, which has a uniform spatial distribution and the electron energy in the range of 100 to 200 MeV, with a natural uranium target [2]. The main functions of the facility are the production of medical isotopes and the support of the Ukraine nuclear power industry. Neutron beam experiments and material studies are also included. Over the past two-three decades, structures with characteristic lengths of 100 {angstrom} and correspondingly smaller vibrational energies have become increasingly important for both science and technology [3]. The characteristic dimensions of the microstructures can be well matched by neutrons with longer vibrational wavelength and lower energy. In the accelerator-driven subcritical facility, most of the neutrons are generated from fission reactions with energy in the MeV range. They are slowed down to the meV energy range through scattering reactions in the moderator and reflector materials. However, the fraction of neutrons with energies less than 5 meV in a normal moderator spectrum is very low because of up-scattering caused by the thermal motion of moderator or reflector molecules. In order to obtain neutrons with energy less than 5 meV, cryogenically cooled moderators 'cold neutron sources' should be used to slow down the neutrons. These cold moderators shift the neutron energy spectrum down because the thermal motion of moderator molecules as well as the up-scattering is very small, which provides large gains in intensity of low energy neutrons, E < 5 meV. The accelerator driven subcritical facility is designed with a provision to add a cryogenically cooled moderator system. This cold neutron source could provide the neutrons beams with lower energy, which could be utilized in scattering experiment and material structures analysis. This study describes the performed physics analyses to define and characterize the cold neutron source of the KIPT neutron source facility. The cold neutron source is designed to optimize the cold neutron brightness to the experimental instruments outside the radial heavy concrete shield of the facility. Liquid hydrogen or solid methane with 20 K temperature is used as a cold moderator. Monte Carlo computer code MCNPX [4], with ENDF/B-VI nuclear data libraries, is utilized to calculate the cold neutron source performance and estimate the nuclear heat load to the cold moderator. The surface source generation capability of MCNPX code has been used to provide the possibility of analyzing different design configurations and perform design optimization analyses with reasonable computer resources. Several design configurations were analyzed and their performance were characterized and optimized.

  10. Crystal Driven Neutron Source: A New Paradigm for Miniature Neutron Sources

    SciTech Connect

    Tang, V.; Meyer, G.; Falabella, S.; Guethlein, G.; Kerr, P.; Park, H. G.; Rusnak, B.; Sampayan, S.; Schmid, G.; Spadaccini, C.; Wang, L.; Morse, J.

    2009-03-10

    Neutron interrogation techniques have specific advantages for detection of hidden, shielded, or buried threats over other detection modalities in that neutrons readily penetrate most materials providing backscattered gammas indicative of the elemental composition of the potential threat. Such techniques have broad application to military and homeland security needs. Present neutron sources and interrogation systems are expensive and relatively bulky, thereby making widespread use of this technique impractical. Development of a compact, high intensity crystal driven neutron source is described. The crystal driven neutron source approach has been previously demonstrated using pyroelectric crystals that generate extremely high voltages when thermal cycled. Placement of a sharpened needle on the positively polarized surface of the pyroelectric crystal results in sufficient field intensification to field ionize background deuterium molecules in a test chamber, and subsequently accelerate the ions to energies in excess of {approx}100 keV, sufficient for either D-D or D-T fusion reactions with appropriate target materials. Further increase in ion beam current can be achieved through optimization of crystal thermal ramping, ion source and crystal accelerator configuration. The advantage of such a system is the compact size along with elimination of large, high voltage power supplies. A novel implementation discussed incorporates an independently controlled ion source in order to provide pulsed neutron operation having microsecond pulse width.

  11. Crystal Driven Neutron Source: A New Paradigm for Miniature Neutron Sources

    SciTech Connect

    Tang, V; Morse, J; Meyer, G; Falabella, S; Guethlein, G; Kerr, P; Park, H G; Rusnak, B; Sampayan, S; Schmid, G; Spadaccini, C; Wang, L

    2008-08-08

    Neutron interrogation techniques have specific advantages for detection of hidden, shielded, or buried threats over other detection modalities in that neutrons readily penetrate most materials providing backscattered gammas indicative of the elemental composition of the potential threat. Such techniques have broad application to military and homeland security needs. Present neutron sources and interrogation systems are expensive and relatively bulky, thereby making widespread use of this technique impractical. Development of a compact, high intensity crystal driven neutron source is described. The crystal driven neutron source approach has been previously demonstrated using pyroelectric crystals that generate extremely high voltages when thermal cycled [1-4]. Placement of a sharpened needle on the positively polarized surface of the pyroelectric crystal results in sufficient field intensification to field ionize background deuterium molecules in a test chamber, and subsequently accelerate the ions to energies in excess of {approx}100 keV, sufficient for either D-D or D-T fusion reactions with appropriate target materials. Further increase in ion beam current can be achieved through optimization of crystal thermal ramping, ion source and crystal accelerator configuration. The advantage of such a system is the compact size along with elimination of large, high voltage power supplies. A novel implementation discussed incorporates an independently controlled ion source in order to provide pulsed neutron operation having microsecond pulse width.

  12. DPA calculation for Japanese spallation neutron source

    NASA Astrophysics Data System (ADS)

    Harada, M.; Watanabe, N.; Konno, C.; Meigo, S.; Ikeda, Y.; Niita, K.

    2005-08-01

    A neutron generating target and surrounding components, such as moderators and proton-beam windows, of intense pulsed spallation sources suffer serious radiation damage. In order to construct a maintenance scenario of the Japanese Spallation Neutron Source, the life estimation of those components due to the radiation damage becomes indispensable. For this purpose, we calculated DPA values of the important components, based on the calculation of displacement cross-sections using PHITS and NJOY codes with the LA150 library. Maximum DPA values at the end of 5000 MW h are 3.9 for the target vessel, 2.8 for the reflector and moderator vessels, and 0.4 for the proton-beam window. We also discuss the effect of the proton-beam profile and proton-energy dependence on the DPA values. Briefly, we showed the calculation result on the helium and hydrogen production.

  13. INJECTION CHOICE FOR SPALLATION NEUTRON SOURCE RING.

    SciTech Connect

    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.

  14. Advanced Neutron Sources: Plant Design Requirements

    SciTech Connect

    Not Available

    1990-07-01

    The Advanced Neutron Source (ANS) is a new, world class facility for research using hot, thermal, cold, and ultra-cold neutrons. At the heart of the facility is a 350-MW{sub th}, heavy water cooled and moderated reactor. The reactor is housed in a central reactor building, with supporting equipment located in an adjoining reactor support building. An array of cold neutron guides fans out into a large guide hall, housing about 30 neutron research stations. Office, laboratory, and shop facilities are included to provide a complete users facility. The ANS is scheduled to begin operation at the Oak Ridge National Laboratory at the end of the decade. This Plant Design Requirements document defines the plant-level requirements for the design, construction, and operation of the ANS. This document also defines and provides input to the individual System Design Description (SDD) documents. Together, this Plant Design Requirements document and the set of SDD documents will define and control the baseline configuration of the ANS.

  15. The Advanced Neutron Source liquid deuterium cold source

    SciTech Connect

    Lucas, A.T.

    1995-08-01

    The Advanced Neutron Source will employ two cold sources to moderate neutrons to low energy (<10 meV). The cold neutrons produced are then passed through beam guides to various experiment stations. Each cold source moderator is a sphere of 410-mm internal diameter. The moderator material is liquid deuterium flowing at a rate of 1 kg/s and maintained at subcooled temperatures at all points of the circuit, to prevent boiling. Nuclear beat deposited within the liquid deuterium and its containment structure totals more than 30 kW. All of this heat is removed by the liquid deuterium, which raises its temperature by 5 K. The liquid prime mover is a cryogenic circulator that is situated in the return leg of the flow loop. This arrangement minimizes the heat added to the liquid between the heat exchanger and the moderator vessel, allowing the moderator to be operated at the minimum practical temperature. This report describes the latest thinking at the time of project termination. It also includes the status of various systems at that time and outlines anticipated directions in which the design would have progressed. In this regard, some detail differences between this report and official design documents reflect ideas that were not approved at the time of closure but are considered noteworthy.

  16. New sources and instrumentation for neutrons in biology

    PubMed Central

    Teixeira, S.C.M.; Ankner, J.; Bellissent-Funel, M.C.; Bewley, R.; Blakeley, M.P.; Coates, L.; Dahint, R.; Dalgliesh, R.; Dencher, N.; Dhont, J.; Fischer, P.; Forsyth, V.T.; Fragneto, G.; Frick, B.; Geue, T.; Gilles, R.; Gutberlet, T.; Haertlein, M.; Hauß, T.; Häußler, W.; Heller, W.T.; Herwig, K.; Holderer, O.; Juranyi, F.; Kampmann, R.; Knott, R.; Kohlbrecher, J.; Kreuger, S.; Langan, P.; Lechner, R.; Lynn, G.; Majkrzak, C.; May, R.; Meilleur, F.; Mo, Y.; Mortensen, K.; Myles, D.A.A.; Natali, F.; Neylon, C.; Niimura, N.; Ollivier, J.; Ostermann, A.; Peters, J.; Pieper, J.; Rühm, A.; Schwahn, D.; Shibata, K.; Soper, A.K.; Straessle, T.; Suzuki, U.-i.; Tanaka, I.; Tehei, M.; Timmins, P.; Torikai, N.; Unruh, T.; Urban, V.; Vavrin, R.; Weiss, K.; Zaccai, G.

    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. PMID:19132140

  17. Spallation neutron source beam loss monitor system

    NASA Astrophysics Data System (ADS)

    Gassner, D.; Witkover, R.; Cameron, P.; Power, J.

    2000-11-01

    The Spallation Neutron Source facility to be built at ORNL is designed to accumulate 2×1014 protons at 1.0 GeV and deliver them to the experimental target in one bunch at 60 Hz. To achieve this goal and protect the machine from excessive radiation activation, an uncontrolled loss criteria of 1 part in 104 (1 W/m) has been specified. Measured losses will be conditioned to provide machine tuning data, a beam abort trigger, and logging of loss history. The design of the distributed loss monitor system utilizing argon-filled glass ionization chambers and scintillator-photomultipliers will be presented.

  18. European Spallation Source and Neutron Science

    NASA Astrophysics Data System (ADS)

    Yeck, James

    2014-03-01

    International collaborations in large-scale scientific projects can link Sciences and Society. Following this goal, the European Spallation Source (ESS) is a multi-disciplinary research centre under design and construction in Lund, Sweden. This new facility is funded by a collaboration of 17 European countries. Scandinavia is providing 50 percent of the construction cost whilst the other member states are providing financial support mainly via in-kind contribution from institutes, laboratories or industries of the given countries. Scientists and engineers from 35 different countries are members of the workforce in Lund who participate in its design and construction. The ESS will enable new opportunities for researchers in fields of life sciences, energy, environmental technology, cultural heritage and fundamental physics by producing very high flux neutrons to study condensed matter physics, chemistry, biology, nuclear physics and materials science. The ESS will be up to 30 times brighter than today's leading facilities and neutron sources. A tungsten target and a 5 MW long pulse proton accelerator, composed mainly of superconducting Radio-Frequency components, are used to achieve these goals.

  19. Status of the intense pulsed neutron source

    SciTech Connect

    Carpenter, J.M.; Brown, B.S.; Kustom, R.L.; Lander, G.H.; Potts, C.W.; Schulke, A.W.; Wuestefeld, G.

    1985-01-01

    Fortunately in spite of some premature reports of its impending demise, IPNS has passed the fourth anniversary of the first delivery of protons to the targets (May 5, 1981) and is approaching the fourth anniversary of its operation as a scattering facility (August 4, 1981). On June 10, 1984, the RCS delivered its one billionth pulse to the IPNS target - the total number of protons delivered to the targets amounted then to 75 stp cm/sup 3/ of H/sub 2/ gas. Since startup IPNS has improved steadily in terms of the performance of the Rapid Cycling Synchrotron, the source and its moderators and the scattering instruments, and a substantial and productive user program has evolved. This report summarizes the current status of the Intense Pulsed Neutron Source at Argonne National Laboratory. We include reference to recent accelerator operating experience, neutron facility operating experience, improvements to these systems, design work on the ASPUN high-current facility, booster target design, the new solid methane moderator, characterization of the room temperature moderators, and provide some examples of recent results from several of the spectrometers.

  20. Standard fields of old neutron sources--parameters and traceability.

    PubMed

    Józefowicz, Krystyna; Golnik, Natalia; Zielczy?ski, Mieczys?aw

    2004-01-01

    Standard neutron fields of isotope neutron sources, established in the Institute of Atomic Energy, Poland, have been examined for nearly 20 y. The neutron dose equivalent and gamma dose rates were measured, applying various techniques. The neutron emission of standard neutron sources of 241Am-Be and 252Cf has been originally determined in primary standard laboratory, then checked, making use of transfer instrument calibrated in primary laboratory. The growth of neutron emission of 239Pu-Be source, used for routine calibrations, has been demonstrated. The total uncertainty of determined parameters has been discussed. The periodically repeated checks of neutron fields of standard sources with the use of transfer instrument, calibrated in primary laboratory, should provide the traceability to primary laboratory and the fields could be officially recognised. PMID:15353631

  1. INNOVATIVE ACCELERATOR BASED NEUTRON SOURCE B. F. Bayanov1

    E-print Network

    Taskaev, Sergey Yur'evich

    is then irradiated with epithermal neutrons that are captured by 10 B isotope. Capturing neutrons causes the boron of suitable neutron sources that are compactible with installation in a hospital enviroment. A low of an accelerator with proton beam intensity of 10 mA will decrease exposure time for necessary therapeutic dose

  2. Solid Targets for Neutron Spallation Sources

    E-print Network

    McDonald, Kirk

    targets produce higher neutron fluxes than liquid metal targets · Neutron flux ~ neutron production is less than 30%, solid tungsten targets will generate equal or greater neutron flux than liquid metal · Liquid metal targets distribute the decay heat within the total liquid metal volume, typically ~100x

  3. neutron density. The neutron density (nn) of the source was modeled by solving the simul-

    E-print Network

    West, Stuart

    neutron density. The neutron density (nn) of the source was modeled by solving the simul- taneous-source operates at T È 1 Â 108 K and the 22Ne source operates at T È 3 Â 108 K (8, 23). Coupled models of stellar

  4. The Spallation Neutron Source accelerator system design

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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 approximately 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. PMID:20192394

  6. Electronic neutron sources for compensated porosity well logging

    NASA Astrophysics Data System (ADS)

    Chen, A. X.; Antolak, A. J.; Leung, K.-N.

    2012-08-01

    The viability of replacing Americium-Beryllium (Am-Be) radiological neutron sources in compensated porosity nuclear well logging tools with D-T or D-D accelerator-driven neutron sources is explored. The analysis consisted of developing a model for a typical well-logging borehole configuration and computing the helium-3 detector response to varying formation porosities using three different neutron sources (Am-Be, D-D, and D-T). The results indicate that, when normalized to the same source intensity, the use of a D-D neutron source has greater sensitivity for measuring the formation porosity than either an Am-Be or D-T source. The results of the study provide operational requirements that enable compensated porosity well logging with a compact, low power D-D neutron generator, which the current state-of-the-art indicates is technically achievable.

  7. New opportunities in neutron capture research using advanced pulsed neutron sources

    SciTech Connect

    Bowman, C.D.

    1987-08-01

    The extraordinary neutron intensities available from the new spallation pulsed neutron sources open up exciting opportunities for basic and applied research in neutron nuclear physics. Prospective experiments are reviewed with particular attention to those with a strong connection to capture gamma-ray spectroscopy.

  8. H- radio frequency source development at the Spallation Neutron Source

    SciTech Connect

    Welton, Robert F; Pennisi, Terry R; Roseberry, Ron T; Stockli, Martin P

    2012-01-01

    The Spallation Neutron Source (SNS) now routinely operates nearly 1 MW of beam power on target with a highly persistent {approx}38 mA peak current in the linac and an availability of {approx}90%. H{sup -} beam pulses ({approx}1 ms, 60 Hz) are produced by a Cs-enhanced, multicusp ion source closely coupled with an electrostatic low energy beam transport (LEBT), which focuses the 65 kV beam into a radio frequency quadrupole accelerator. The source plasma is generated by RF excitation (2 MHz, {approx}60 kW) of a copper antenna that has been encased with a thickness of {approx}0.7 mm of porcelain enamel and immersed into the plasma chamber. The ion source and LEBT normally have a combined availability of {approx}99%. Recent increases in duty-factor and RF power have made antenna failures a leading cause of downtime. This report first identifies the physical mechanism of antenna failure from a statistical inspection of {approx}75 antennas which ran at the SNS, scanning electron microscopy studies of antenna surface, and cross sectional cuts and analysis of calorimetric heating measurements. Failure mitigation efforts are then described which include modifying the antenna geometry and our acceptance/installation criteria. Progress and status of the development of the SNS external antenna source, a long-term solution to the internal antenna problem, are then discussed. Currently, this source is capable of delivering comparable beam currents to the baseline source to the SNS and, an earlier version, has briefly demonstrated unanalyzed currents up to {approx}100 mA (1 ms, 60 Hz) on the test stand. In particular, this paper discusses plasma ignition (dc and RF plasma guns), antenna reliability, magnet overheating, and insufficient beam persistence.

  9. H- radio frequency source development at the Spallation Neutron Source.

    PubMed

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

    2012-02-01

    The Spallation Neutron Source (SNS) now routinely operates nearly 1 MW of beam power on target with a highly persistent ?38 mA peak current in the linac and an availability of ?90%. H(-) beam pulses (?1 ms, 60 Hz) are produced by a Cs-enhanced, multicusp ion source closely coupled with an electrostatic low energy beam transport (LEBT), which focuses the 65 kV beam into a radio frequency quadrupole accelerator. The source plasma is generated by RF excitation (2 MHz, ?60 kW) of a copper antenna that has been encased with a thickness of ?0.7 mm of porcelain enamel and immersed into the plasma chamber. The ion source and LEBT normally have a combined availability of ?99%. Recent increases in duty-factor and RF power have made antenna failures a leading cause of downtime. This report first identifies the physical mechanism of antenna failure from a statistical inspection of ?75 antennas which ran at the SNS, scanning electron microscopy studies of antenna surface, and cross sectional cuts and analysis of calorimetric heating measurements. Failure mitigation efforts are then described which include modifying the antenna geometry and our acceptance?installation criteria. Progress and status of the development of the SNS external antenna source, a long-term solution to the internal antenna problem, are then discussed. Currently, this source is capable of delivering comparable beam currents to the baseline source to the SNS and, an earlier version, has briefly demonstrated unanalyzed currents up to ?100 mA (1 ms, 60 Hz) on the test stand. In particular, this paper discusses plasma ignition (dc and RF plasma guns), antenna reliability, magnet overheating, and insufficient beam persistence. PMID:22380234

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

    PubMed

    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

  11. Neutron calibration sources in the Daya Bay experiment

    NASA Astrophysics Data System (ADS)

    Liu, J.; Carr, R.; Dwyer, D. A.; Gu, W. Q.; Li, G. S.; McKeown, R. D.; Qian, X.; Tsang, R. H. M.; Wu, F. F.; Zhang, C.

    2015-10-01

    We describe the design and construction of the low rate neutron calibration sources used in the Daya Bay Reactor Anti-neutrino Experiment. Such sources are free of correlated gamma-neutron emission, which is essential in minimizing induced background in the anti-neutrino detector. The design characteristics have been validated in the Daya Bay anti-neutrino detector.

  12. Neutron calibration sources in the Daya Bay experiment

    DOE PAGESBeta

    Liu, J.; Carr, R.; Dwyer, D. A.; Gu, W. Q.; Li, G. S.; McKeown, R. D.; Qian, X.; Tsang, R. H. M.; Wu, F. F.; Zhang, C.

    2015-07-09

    We describe the design and construction of the low rate neutron calibration sources used in the Daya Bay Reactor Anti-neutrino Experiment. Such sources are free of correlated gamma-neutron emission, which is essential in minimizing induced background in the anti-neutrino detector. Thus, the design characteristics have been validated in the Daya Bay anti-neutrino detector.

  13. The national spallation neutron source target station: A general overview

    SciTech Connect

    Gabriel, T.A.; Barnes, J.N.; Charlton, L.A.

    1997-06-01

    The technologies that are being utilized to design and build a state-of-the-art neutron spallation source, the National Spallation Neutron Source (NSNS), are discussed. Emphasis is given to the technology issues that present the greatest scientific challenges. The present facility configuration, ongoing analysis and the planned hardware research and development program are also described.

  14. Overview of the Target Systems for the Spallation Neutron Source

    SciTech Connect

    Gabriel, T.A.; Haines, J.R.; McManamy, T.J.

    1998-10-15

    The technologies that are being utilized to design and build the target systems for a state-of-the-art accelerator- based neutron source, the Spallation Neutron Source (SNS), are discussed. Emphasis is given to the technology issues that present the greatest challenges. The present facility configuration, ongoing analysis, and planned research and development program are also described.

  15. PREFACE: Neutrino physics at spallation neutron sources

    NASA Astrophysics Data System (ADS)

    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 to enrich our knowledge of neutrino physics and the multifaceted science it interfaces. In fact, the neutrino energy spectra expected at spallation neutron facilities overlap remarkably with those emanating from distant supernovae and these sources seem `made to order' for terrestrial studies of supernova reactions. They are also in a suitable energy regime to pursue neutrino-mediated studies of nuclear structure, fundamental symmetries and solar reactions. Recent research indicates neutrino-nuclear reactions may be even more influential in supernova dynamics and detection than hitherto believed. The need for in-depth understanding of the individual neutrino-nuclear reactions that collectively have dramatic effects on the large-scale dynamics of evolving stars points to laboratory measurements of neutrino reactions on various nuclei as a premier requirement of neutrino-nuclear astrophysics. Such experimental data can improve our input to the extensive modelling projects that investigate the evolutionary stages of exploding supernovae and further our understanding of their internal physics. State-of-the-art simulations exploring the neutrino-reheating phases fail to produce explosions---yet clearly nature explodes her supernovae. Matters pertaining to the galactic abundance of very p-rich nuclei and the various isotope ratios are by no means well defined and demand further research, as do the intricacies of the nucleo-synthesis channels. Neutrino-nuclear experiments are also essential for proper development and calibration of appropriate supernova detectors. Solar neutrino research and detection have contributed vastly to our current understanding of neutrino science and have helped to validate the standard solar model. The chapter is by no means closed and experiments with intense neutrino fluxes could enrich valuably our understanding of both neutrino and solar physics. Neutrino nuclear reactions are not only important for their role in nuclear astrophysics, but also for the insight they provide on nuclear structure and the theoretical models used to calculat

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

    SciTech Connect

    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 reencapsulators domestically and internationally. Sealed {sup 252}Cf sources are also available for loan to agencies and subcontractors of the U.S. 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 {sup 252}Cf 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.

  17. An overview of the planned advanced neutron source facility

    SciTech Connect

    West, C.D.

    1990-01-01

    The Advanced Neutron Source (ANS), now in the conceptual design stage, will be a new user facility for neutron research, including neutron beam experiments, materials irradiation testing and materials analysis capabilities, and production facilities for transuranic and lighter isotopes. The neutron source is to be the world's highest flux beam reactor and is based on existing reactor technology to minimize safety issues. The preferred fuel, U{sub 3}Si{sub 2}, has been tested in operating reactors in the United States, Japan, and Europe. The core is cooled, moderated, and reflected by heavy water, common practice for research reactors. 3 refs., 9 figs., 3 tabs.

  18. Virtual Gamma Ray Radiation Sources through Neutron Radiative Capture

    SciTech Connect

    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.

  19. Fissile mass estimation by pulsed neutron source interrogation

    NASA Astrophysics Data System (ADS)

    Israelashvili, I.; Dubi, C.; Ettedgui, H.; Ocherashvili, A.; Pedersen, B.; Beck, A.; Roesgen, E.; Crochmore, J. M.; Ridnik, T.; Yaar, I.

    2015-06-01

    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.

  20. 78 FR 21567 - Installation of Radiation Alarms for Rooms Housing Neutron Sources

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-11

    ...of Radiation Alarms for Rooms Housing Neutron Sources AGENCY: Nuclear Regulatory Commission...of radiation alarms for rooms housing neutron sources. DATES: The docket for the petition...of radiation alarms for rooms housing neutron sources. The petitioner stated that...

  1. 76 FR 76327 - Installation of Radiation Alarms for Rooms Housing Neutron Sources

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-07

    ...of Radiation Alarms for Rooms Housing Neutron Sources AGENCY: Nuclear Regulatory Commission...installation of radiation alarms in rooms housing neutron sources. DATES: Submit comments by February...Hamawy is concerned about the security of neutron sources. III. Petition The...

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

    SciTech Connect

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

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

    SciTech Connect

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

    1992-01-01

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

  4. Pulsed neutron source cold moderators --- concepts, design and engineering

    SciTech Connect

    Bauer, Guenter S.

    1997-01-01

    Moderator design for pulsed neutron sources is becoming more and more an interface area between source designers and instrument designers. Although there exists a high degree of flexibility, there are also physical and technical limitations. This paper aims at pointing out these limitations and examining ways to extend the current state of moderator technology in order to make the next generation neutron sources even more versatile and flexible tools for science in accordance with the users' requirements. (auth)

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

    PubMed

    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

  6. Neutron sources for test and calibration of neutron detectors for space research

    NASA Astrophysics Data System (ADS)

    Granja, C.; Kralik, M.; Kohout, Z.; Masek, P.; Pospisil, S.; Solar, M.; Solc, J.; Vykydal, Z.; Owens, A.; Vacik, J.; Chvatil, D.; Bem, P.; Krist, P.; Stursa, J.; Rypar, V.

    2012-02-01

    This work reports on the current status of neutron sources in the Czech Republic as calibrated and ESA compliant stations for space related applications such as the testing and calibration of neutron detectors and neutron sensitive devices as well as for studies of radiation effects of electric and electronic components. The work was carried out as part of the preparatory accession activities of the Czech Republic with ESA. The goal and one of the tasks is to test and evaluate neutron sensitive devices, both conventional and prototypes, developed at ESA and at the IEAP CTU Prague. The facilities consist of both fast and thermal neutron sources providing testing and absolute calibration of a wide range of neutron detectors. The evaluation and calibration of the sources were carried out in cooperation with the Nuclear Physics Institute, Academy of Sciences of the Czech Republic, the Research Center Rez, and the Czech Metrology Institute in Prague.

  7. A Dipole Assisted IEC Neutron Source

    SciTech Connect

    Prajakti Joshi Shrestha

    2005-11-28

    A potential opportunity to enhance Inertial Electrostatic Confinement (IEC) fusion exists by augmenting it with a magnetic dipole configuration. The theory is that the dipole fields will enhance the plasma density in the center region of the IEC and the combined IEC and dipole confinement properties will reduce plasma losses. To demonstrate that a hybrid Dipole-IEC configuration can provide an improved neutron source vs. a stand alone IEC, a first model Dipole-IEC experiment was benchmarked against a reference IEC. A triple Langmuir probe was used to find the electron temperature and density. It was found that the magnetic field increases the electron density by a factor of 16, the electron temperature decreases in the presence of a magnetic field, the discharge voltage decreases in the presence of a magnetic field, the potential of the dipole strongly influences the densities obtained in the center. The experimental set-up and plasma diagnostics are discussed in detail, as well as the results, and the developmental issues.

  8. Characterization of short-pulse laser driven neutron source

    NASA Astrophysics Data System (ADS)

    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.

  9. Microtron MT 25 as a source of neutrons

    SciTech Connect

    Kralik, M.; Solc, J.; Chvatil, D.; Krist, P.; Turek, K.; Granja, C.

    2012-08-15

    The objective was to describe Microtron MT25 as a source of neutrons generated by bremsstrahlung induced photonuclear reactions in U and Pb targets. Bremsstrahlung photons were produced by electrons accelerated at energy 21.6 MeV. Spectral fluence of the generated neutrons was calculated with MCNPX code and then experimentally determined at two positions by means of a Bonner spheres spectrometer in which the detector of thermal neutrons was replaced by activation Mn tablets or track detectors CR-39 with a {sup 10}B radiator. The measured neutron spectral fluence and the calculated anisotropy served for the estimation of neutron yield from the targets and for the determination of ambient dose equivalent rate at the place of measurement. Microtron MT25 is intended as one of the sources for testing neutron sensitive devices which will be sent into the space.

  10. Facility for fast neutron irradiation tests of electronics at the ISIS spallation neutron source

    SciTech Connect

    Andreani, C.; Pietropaolo, A.; Salsano, A.; Gorini, G.; Tardocchi, M.; Paccagnella, A.; Gerardin, S.; Frost, C. D.; Ansell, S.; Platt, S. P.

    2008-03-17

    The VESUVIO beam line at the ISIS spallation neutron source was set up for neutron irradiation tests in the neutron energy range above 10 MeV. The neutron flux and energy spectrum were shown, in benchmark activation measurements, to provide a neutron spectrum similar to the ambient one at sea level, but with an enhancement in intensity of a factor of 10{sup 7}. Such conditions are suitable for accelerated testing of electronic components, as was demonstrated here by measurements of soft error rates in recent technology field programable gate arrays.

  11. Neutron producing target for accelerator based neutron source for

    E-print Network

    Taskaev, Sergey Yur'evich

    beam. v) Cleaning the target surface from radioactive 7 Be isotope. Liquid metal heat carrier was proposed to cool the target, instead of water. Liquid metal heat carrier allows to keep lower temperature specimen of neutron producing stationary target with liquid metal heat carrier was made (Fig. 1). Steel

  12. Summary of alpha-neutron sources in GADRAS.

    SciTech Connect

    Mitchell, Dean James; Thoreson, Gregory G.; Harding, Lee T.

    2012-05-01

    A common source of neutrons for calibration and testing is alpha-neutron material, named for the alpha-neutron nuclear reaction that occurs within. This material contains a long-lived alpha-emitter and a lighter target element. When the alpha particle from the emitter is absorbed by the target, neutrons and gamma rays are released. Gamma Detector Response and Analysis Software (GADRAS) includes built-in alpha-neutron source definitions for AcC, AmB, AmBe, AmF, AmLi, CmC, and PuC. In addition, GADRAS users may create their own alpha-neutron sources by placing valid alpha-emitters and target elements in materials within their one-dimensional models (1DModel). GADRAS has the ability to use pre-built alpha-neutron sources for plotting or as trace-sources in 1D models. In addition, if any material (existing or user-defined) specified in a 1D model contains both an alpha emitter in conjunction with a target nuclide, or there is an interface between such materials, then the appropriate neutron-emission rate from the alpha-neutron reaction will be computed. The gamma-emissions from these sources are also computed, but are limited to a subset of nine target nuclides. If a user has experimental data to contribute to the alpha-neutron gamma emission database, it may be added directly or submitted to the GADRAS developers for inclusion. The gadras.exe.config file will be replaced when GADRAS updates are installed, so sending the information to the GADRAS developers is the preferred method for updating the database. This is also preferable because it enables other users to benefit from your efforts.

  13. A Bright Neutron Source Driven by a Short Pulse Laser

    NASA Astrophysics Data System (ADS)

    Roth, Markus

    2012-10-01

    Neutrons are a unique tool to alter and diagnose material properties, and to exciting nuclear reactions, for many applications. Accelerator based spallation sources provide high neutron fluxes for research, but there is a growing need for more compact sources with higher peak brightness, whether fast or moderated neutrons. Intense lasers promise such as source, readily linkable to other experimental facilities, or deployable outside a laboratory setting. We present experimental results on the first short-pulse laser-driven neutron source powerful enough for radiography. A novel laser-driven ion acceleration mechanism (Breakout Afterburner), operating in the relativistic transparency regime, is used. Based on the mechanism's advantages, a laser-driven deuteron beam is used to achieve a new record in laser-neutron production, in numbers, energy and directionality. This neutron beam is a highly directional pulse < 1 ns at ˜ 1 cm from the target, with a flux > 40/2?, and thus suitable for imaging applications with high temporal resolution. The beam contained, for the first time, neutrons with energies of up to 150 MeV. Thus using short pulse lasers, it is now possible to use the resulting hard x-rays and neutrons of different energies to radiograph an unknown object and to determine its material composition. Our data matches the simulated data for our test samples.

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

    PubMed

    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

  15. Advanced Neutron Source radiological design criteria

    SciTech Connect

    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.

  16. Radionuclide neutron sources in calibration laboratory--neutron and gamma doses and their changes in time.

    PubMed

    Józefowicz, K; Golnik, N; Tulik, P; Zielczynski, M

    2007-01-01

    The calibration laboratory, having standard neutron fields of radionuclide sources, should perform regular measurements of fields' parameters in order to check their stability and to get knowledge of any changes. Usually, accompanying gamma radiation is not of serious concern, but some personal dosemeters, old neutron dose equivalent meters with scintillation detectors and the dose meters of mixed radiation require the determination of this component. In the Laboratory of Radiation Protection Measurements in the Institute of Atomic Energy, Poland, the fields of radionuclide neutron sources (252)Cf, (241)Am-Be and (239)Pu-Be were examined for nearly 20 y. A number of detectors and methods have been applied for the determination of neutron ambient dose equivalent rate and for the determination of neutron and gamma dose components. This paper presents the recent results of measurements of gamma and neutron dose and dose equivalent, compared with the results accumulated in nearly 20 y. PMID:17513855

  17. Compact, energy EFFICIENT neutron source: enabling technology for various applications

    SciTech Connect

    Hershcovitch, A.; Roser, T.

    2009-12-01

    A novel neutron source comprising of a deuterium beam (energy of about 100 KeV) injected into a tube filled with tritium gas and/or tritium plasma that generates D-T fusion reactions, whose products are 14.06 MeV neutrons and 3.52 MeV alpha particles, is described. At the opposite end of the tube, the energy of deuterium ions that did not interact is recovered. Beryllium walls of proper thickness can be utilized to absorb 14 MeV neutrons and release 2-3 low energy neutrons. Each ion source and tube forms a module. Larger systems can be formed from multiple units. Unlike currently proposed methods, where accelerator-based neutron sources are very expensive, large, and require large amounts of power for operation, this neutron source is compact, inexpensive, easy to test and to scale up. Among possible applications for this neutron source concept are sub-critical nuclear breeder reactors and transmutation of radioactive waste.

  18. Slower, colder, longer : prospects for a very cold neutron source.

    SciTech Connect

    Micklich, B. J.; Carpenter, J. M.; Intense Pulsed Neutron Source

    2007-01-01

    The motivation for our study is to establish the prospects for a neutron source providing intense pulsed beams with spectra as cold as is realistic. The scientific motivation is to serve applications in nanoscience, biology and technology.

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

    NASA Astrophysics Data System (ADS)

    Fomin, N.; Greene, G. L.; Allen, R. R.; Cianciolo, V.; Crawford, C.; Tito, T. M.; Huffman, P. R.; Iverson, E. B.; Mahurin, R.; Snow, W. M.

    2015-02-01

    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. Brazilian gamma-neutron dosemeter: response to 241AmBe and 252Cf neutron sources.

    PubMed

    Souto, E B; Campos, L L

    2011-03-01

    With the aim of improving the monitoring of workers potentially exposed to neutron radiation in Brazil, the IPEN/CNEN-SP in association with PRO-RAD designed and developed a passive individual gamma-neutron mixed-field dosemeter calibrated to be used to (241)AmBe sources. To verify the dosimetry system response to different neutron spectra, prototypes were irradiated with a (252)Cf source and evaluated using the dose-calculation algorithm developed for (241)AmBe sources. PMID:21186217

  1. Overview of target systems for the Spallation Neutron Source

    SciTech Connect

    Gabriel, Tony A.; Barnes, John M.; Charlton, Lowell A.; DiStefano, James; Farrell, Ken; Haines, John; Johnson, Jeffrey O.; Mansur, Louis K.; Pawel, Steve J.; Siman-Tov, Moshe; Taleyarkhan, Rusi; Wendel, Mark W.; McManamy, Thomas J.; Rennich, Mark J.

    1997-01-01

    The purpose and requirements of target systems as well as the technologies that are being utilized to design and build a state-of-the-art neutron spallation source, the Spallation Neutron Source (SNS), are discussed. Emphasis is given to the technology issues that present the greatest scientific challenges. The present facility configuration, ongoing analysis, and the planned hardware research and development program are also described.

  2. Characteristics of the WNR: a pulsed spallation neutron source

    SciTech Connect

    Russell, G.J.; Lisowski, P.W.; Howe, S.D.; King, N.S.P.; Meier, M.M.

    1982-01-01

    The Weapons Neutron Research facility (WNR) is a pulsed spallation neutron source in operation at the Los Alamos National Laboratory. The WNR uses part of the 800-MeV proton beam from the Clinton P. Anderson Meson Physics Facility accelerator. By choosing different target and moderator configurations and varying the proton pulse structure, the WNR can provide a white neutron source spanning the energy range from a few MeV to 800 MeV. The neutron spectrum from a bare target has been measured and is compared with predictions using an Intranuclear Cascade model coupled to a Monte Carlo transport code. Calculations and measurements of the neutronics of WNR target-moderator assemblies are presented.

  3. Design and Demonstration of a Quasi-monoenergetic Neutron Source

    SciTech Connect

    Joshi, T.; Sangiorgio, Samuele; Mozin, Vladimir V.; Norman, E. B.; Sorensen, Peter F.; Foxe, Michael P.; Bench, G.; Bernstein, A.

    2014-03-05

    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 7Li(p,n)7Be 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 lters such as vanadium and manganese are also explored and the possibility of studying the response of di*erent materials to low-energy nuclear recoils using the resultant neutron beams is discussed.

  4. A compact ion source for intense neutron generation

    NASA Astrophysics Data System (ADS)

    Perkins, Luke Torrilhon

    Today, numerous applications for neutrons, beyond those of the nuclear power industry, are beginning to emerge and become viable. From neutron radiography which, not unlike conventional X-rays, can provide an in-depth image through various materials, to neutron radiotherapy, for the treatment of certain forms of cancer, all these applications promise to improve our quality of life. To meet the growing need for neutrons, greater demands are being made on the neutron 'generator' technology, demands for improved neutron output and reliability at reduced physical sizes and costs. One such example in the field of borehole neutron generators, where, through neutron activation analysis, the elemental composition, concentration and location in the surrounding borehole media can be ascertained. These generators, which commonly rely on the fusion of deuterium (D) and tritium (T) at energies of the order of one hundred thousand Volts, seem to defy their physical limitations to provide neutron outputs approaching a billion per second in packages no greater than two inches in diameter. In an attempt to answer this demand, we, at Lawrence Berkeley National Laboratory (LBNL), have begun developing a new generation of neutron generators making use of recent developments in ion source technology. The specific application which motivates this development is in the environmental monitoring field, where pollutants and their concentrations in the subsurface must be assessed. To achieve the desired direction of low-level concentrations and obtain a better directional sensitivity, a neutron output of 109 to 1010 D-T neutrons per second was targeted for generator package which can fit inside a ~5 cm diameter borehole. To accomplish this performance, a radio-frequency (RF)- driven ion source developed at LBNL was adapted to the requirements of this application. The advantages of this type of ion source are its intrinsic ability to tailor the delivery of RF power to the ion source and therefore control the neutron output (pulse width, repetition rate and magnitude) while operating at low pressures (~5 mTorr). In the experimental testing presented herein, a prototype, 5 cm-diameter, inductively driven ion source has produced unsaturated hydrogen beam current densities in excess of 1 A/cm2 and monatomic species fractions in excess of 90%. This satisfactory performance, with respect to the targeted neutron output, was achieved with a 2 MHz, 60 kW pulse of RF to produce a ~20?s plasma pulse at <100 Hz.

  5. A method for using neutron elastic scatter to create a variable energy neutron beam from a nearly monoenergetic neutron source

    NASA Astrophysics Data System (ADS)

    Whetstone, Z. D.; Kearfott, K. J.

    2015-07-01

    This work describes preliminary investigation into the design of a compact, portable, variable energy neutron source. The proposed method uses elastic neutron scatter at specific angles to reduce the energy of deuterium-deuterium or deuterium-tritium (D-T) neutrons. The research focuses on D-T Monte Carlo simulations, both in idealized and more realistic scenarios. Systematic uncertainty of the method is also analyzed. The research showed promise, but highlighted the need for discrimination of multiply-scattered neutrons, either through a pulsed generator or associated particle imaging.

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

    SciTech Connect

    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.

  7. A Detector for 2-D Neutron Imaging for the Spallation Neutron Source

    SciTech Connect

    Britton Jr, Charles L; Bryan, W. L.; Wintenberg, Alan Lee; Clonts, Lloyd G; Warmack, Robert J Bruce; McKnight, Timothy E; Frank, Steven Shane; Cooper, Ronald G; Dudney, Nancy J; Veith, Gabriel M

    2006-01-01

    Abstract - We have designed, built, and tested a 2-D pixellated thermal neutron detector. The detector is modeled after the MicroMegas-type structure previously published for collider-type experiments. The detector consists of a 4X4 square array of 1 cm 2 pixels each of which is connected to an individual preamplifier-shaper-data acquisition system. The neutron converter is a 10B film on an aluminum substrate. We describe the construction of the detector and the test results utilizing 252Cf sources in Lucite to thermalize the neutrons.Drift electrode (Aluminum) Converter (10B) 3 mm Conversion gap neutron (-900 V)

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

    SciTech Connect

    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.

  9. Body composition to climate change studies - the many facets of neutron induced prompt gamma-ray analysis

    SciTech Connect

    Mitra,S.

    2008-11-17

    In-vivo body composition analysis of humans and animals and in-situ analysis of soil using fast neutron inelastic scattering and thermal neutron capture induced prompt-gamma rays have been described. By measuring carbon (C), nitrogen (N) and oxygen (O), protein, fat and water are determined. C determination in soil has become important for understanding below ground carbon sequestration process in the light of climate change studies. Various neutron sources ranging from radio isotopic to compact 14 MeV neutron generators employing the associated particle neutron time-of-flight technique or micro-second pulsing were implemented. Gamma spectroscopy using recently developed digital multi-channel analyzers has also been described.

  10. Neutron Repulsion Confirmed as Energy Source

    NASA Astrophysics Data System (ADS)

    Manuel, O.; Miller, E.; Katragada, A.

    2001-12-01

    Systematic properties of heavy nuclides reveal a fine structure in Coulomb energy that parallels variations in mass arising from n-n interactions between neutrons. These results confirm an earlier suggestion that n-n interactions in the nucleus are repulsive. Neutron emission may release up to 1.1%-2.4% of the nuclear rest mass as energy. By comparison, 0.8% of the rest mass is converted to energy in hydrogen fusion and 0.1% is converted to energy in fission. Neutron emission in the core of the Sun may trigger a series of reactions that collectively produce the Sun's luminosity and an outpouring of protons and neutrinos from its surface.

  11. Optimizing Moderator Dimensions for Neutron Scattering at the Spallation Neutron Source

    SciTech Connect

    Zhao, Jinkui; Robertson, Lee; Herwig, Kenneth W; Gallmeier, Franz X; Riemer, Bernie

    2013-01-01

    In this work, we investigate the effect of neutron moderator dimensions on the performance of neutron scattering instruments at the Spallation Neutron Source. In a recent study of the planned second target station at the Spallation Neutron Source (SNS) facility [1,2], 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 for a smaller viewing area [4]. 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. We found that the cross-sections of the sample and the neutron guide, respectively, are the deciding factors for choosing the moderator. Beam divergence plays no role as long as it is within the reach of practical constraints. Namely, the required divergence is not too large for the guide or sample to be located close enough to the moderator on an actual spallation source.

  12. Utilization of the intense pulsed neutron source (IPNS) at Argonne National Laboratory for neutron activation analysis

    SciTech Connect

    Heinrich, R.R.; Greenwood, L.R.; Popek, R.J.; Schulke, A.W. Jr.

    1983-01-01

    The Intense Pulsed Neutron Source (IPNS) neutron scattering facility (NSF) has been investigated for its applicability to neutron activation analysis. A polyethylene insert has been added to the vertical hole VT3 which enhances the thermal neutron flux by a factor of two. The neutron spectral distribution at this position has been measured by the multiple-foil technique which utilized 28 activation reactions and the STAYSL computer code. The validity of this spectral measurement was tested by two irradiations of National Bureau of Standards SRM-1571 (orchard leaves), SRM-1575 (pine needles), and SRM-1645 (river sediment). The average thermal neutron flux for these irradiations normalized to 10 ..mu..amp proton beam is 4.0 x 10/sup 11/ n/cm/sup 2/-s. Concentrations of nine trace elements in each of these SRMs have been determined by gamma-ray spectrometry. Agreement of measured values to certified values is demonstrated to be within experiment error.

  13. Epithermal Neutron Source for Neutron Resonance Spectroscopy (NRS) using High Intensity, Short Pulse Lasers

    SciTech Connect

    Higginson, D P; McNaney, J M; Swift, D C; Bartal, T; Hey, D S; Pape, S L; Mackinnon, A; Mariscal, D; Nakamura, H; Nakanii, N; Beg, F N

    2010-04-22

    A neutron source for neutron resonance spectroscopy (NRS) has been developed using high intensity, short pulse lasers. This measurement technique will allow for robust measurements of interior ion temperature of laser-shocked materials and provide insight into equation of state (EOS) measurements. The neutron generation technique uses protons accelerated by lasers off of Cu foils to create neutrons in LiF, through (p,n) reactions with {sup 7}Li and {sup 19}F. The distribution of the incident proton beam has been diagnosed using radiochromic film (RCF). This distribution is used as the input for a (p,n) neturon prediction code which is compared to experimentally measured neutron yields. From this calculation, a total fluence of 1.8 x 10{sup 9} neutrons is infered, which is shown to be a reasonable amount for NRS temperature measurement.

  14. Gyrotron-driven high current ECR ion source for boron-neutron capture therapy neutron generator

    NASA Astrophysics Data System (ADS)

    Skalyga, V.; Izotov, I.; Golubev, S.; Razin, S.; Sidorov, A.; Maslennikova, A.; Volovecky, A.; Kalvas, T.; Koivisto, H.; Tarvainen, O.

    2014-12-01

    Boron-neutron capture therapy (BNCT) is a perspective treatment method for radiation resistant tumors. Unfortunately its development is strongly held back by a several physical and medical problems. Neutron sources for BNCT currently are limited to nuclear reactors and accelerators. For wide spread of BNCT investigations more compact and cheap neutron source would be much more preferable. In present paper an approach for compact D-D neutron generator creation based on a high current ECR ion source is suggested. Results on dense proton beams production are presented. A possibility of ion beams formation with current density up to 600 mA/cm2 is demonstrated. Estimations based on obtained experimental results show that neutron target bombarded by such deuteron beams would theoretically yield a neutron flux density up to 6·1010 cm-2/s. Thus, neutron generator based on a high-current deuteron ECR source with a powerful plasma heating by gyrotron radiation could fulfill the BNCT requirements significantly lower price, smaller size and ease of operation in comparison with existing reactors and accelerators.

  15. Core Vessel Insert Handling Robot for the Spallation Neutron Source

    SciTech Connect

    Graves, Van B; Dayton, Michael J

    2011-01-01

    The Spallation Neutron Source provides the world's most intense pulsed neutron beams for scientific research and industrial development. Its eighteen neutron beam lines will eventually support up to twenty-four simultaneous experiments. Each beam line consists of various optical components which guide the neutrons to a particular instrument. The optical components nearest the neutron moderators are the core vessel inserts. Located approximately 9 m below the high bay floor, these inserts are bolted to the core vessel chamber and are part of the vacuum boundary. They are in a highly radioactive environment and must periodically be replaced. During initial SNS construction, four of the beam lines received Core Vessel Insert plugs rather than functional inserts. Remote replacement of the first Core Vessel Insert plug was recently completed using several pieces of custom-designed tooling, including a highly complicated Core Vessel Insert Robot. The design of this tool are discussed.

  16. Active Neutron-Based Interrogation System with D-D Neutron Source for Detection of Special Nuclear Materials

    NASA Astrophysics Data System (ADS)

    Takahashi, Y.; Misawa, T.; Yagi, T.; Pyeon, C. H.; Kimura, M.; Masuda, K.; Ohgaki, H.

    2015-10-01

    The detection of special nuclear materials (SNM) is an important issue for nuclear security. The interrogation systems used in a sea port and an airport are developed in the world. The active neutron-based interrogation system is the one of the candidates. We are developing the active neutron-based interrogation system with a D-D fusion neutron source for the nuclear security application. The D-D neutron source is a compact discharge-type fusion neutron source called IEC (Inertial-Electrostatic Confinement fusion) device which provides 2.45 MeV neutrons. The nuclear materials emit the highenergy neutrons by fission reaction. High-energy neutrons with energies over 2.45 MeV amount to 30% of all the fission neutrons. By using the D-D neutron source, the detection of SNMs is considered to be possible with the attention of fast neutrons if there is over 2.45 MeV. Ideally, neutrons at En>2.45 MeV do not exist if there is no nuclear materials. The detection of fission neutrons over 2.45 MeV are hopeful prospect for the detection of SNM with a high S/N ratio. In the future, the experiments combined with nuclear materials and a D-D neutron source will be conducted. Furthermore, the interrogation system will be numerically investigated by using nuclear materials, a D-D neutron source, and a steel container.

  17. Time-correlated neutron analysis of a multiplying HEU source

    NASA Astrophysics Data System (ADS)

    Miller, E. C.; Kalter, J. M.; Lavelle, C. M.; Watson, S. M.; Kinlaw, M. T.; Chichester, D. L.; Noonan, W. A.

    2015-06-01

    The ability to quickly identify and characterize special nuclear material remains a national security challenge. In counter-proliferation applications, identifying the neutron multiplication of a sample can be a good indication of the level of threat. Currently neutron multiplicity measurements are performed with moderated 3He proportional counters. These systems rely on the detection of thermalized neutrons, a process which obscures both energy and time information from the source. Fast neutron detectors, such as liquid scintillators, have the ability to detect events on nanosecond time scales, providing more information on the temporal structure of the arriving signal, and provide an alternative method for extracting information from the source. To explore this possibility, a series of measurements were performed on the Idaho National Laboratory's MARVEL assembly, a configurable HEU source. The source assembly was measured in a variety of different HEU configurations and with different reflectors, covering a range of neutron multiplications from 2 to 8. The data was collected with liquid scintillator detectors and digitized for offline analysis. A gap based approach for identifying the bursts of detected neutrons associated with the same fission chain was used. Using this approach, we are able to study various statistical properties of individual fission chains. One of these properties is the distribution of neutron arrival times within a given burst. We have observed two interesting empirical trends. First, this distribution exhibits a weak, but definite, dependence on source multiplication. Second, there are distinctive differences in the distribution depending on the presence and type of reflector. Both of these phenomena might prove to be useful when assessing an unknown source. The physical origins of these phenomena can be illuminated with help of MCNPX-PoliMi simulations.

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

    NASA Astrophysics Data System (ADS)

    Ghetti, R.; Colonna, N.; Helgesson, J.; De Filippo, E.; Tagliente, G.; Anzalone, A.; Bellini, V.; Carlèn, L.; Cavallaro, S.; Celano, L.; D'Erasmo, G.; Di Santo, D.; Fiore, E. M.; Fokin, A.; Geraci, M.; Jakobsson, B.; Kuznetsov, A.; Lanzanò, G.; Mahboub, D.; Murin, Yu.; Mårtensson, 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.; CHIC Collaboration

    1999-12-01

    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.

  19. A thermal neutron source imager using coded apertures

    SciTech Connect

    Vanier, P.E.; Forman, L.; Selcow, E.C.

    1995-08-01

    To facilitate the process of re-entry vehicle on-site inspections, it would be useful to have an imaging technique which would allow the counting of deployed multiple nuclear warheads without significant disassembly of a missile`s structure. Since neutrons cannot easily be shielded without massive amounts of materials, they offer a means of imaging the separate sources inside a sealed vehicle. Thermal neutrons carry no detailed spectral information, so their detection should not be as intrusive as gamma ray imaging. A prototype device for imaging at close range with thermal neutrons has been constructed using an array of {sup 3}He position-sensitive gas proportional counters combined with a uniformly redundant coded aperture array. A sealed {sup 252}Cf source surrounded by a polyethylene moderator is used as a test source. By means of slit and pinhole experiments, count rates of image-forming neutrons (those which cast a shadow of a Cd aperture on the detector) are compared with the count rates for background neutrons. The resulting ratio, which limits the available image contrast, is measured as a function of distance from the source. The envelope of performance of the instrument is defined by the contrast ratio, the angular resolution, and the total count rate as a function of distance from the source. These factors will determine whether such an instrument could be practical as a tool for treaty verification.

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

    SciTech Connect

    Sailor, W.C.; Byrd, R.C.; Gavron, A.; Hammock, R. ); Yariv, Y. )

    1991-11-01

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

  1. Neutron dosimetry, moderated energy spectrum, and neutron capture therapy for californium-252 medical sources

    NASA Astrophysics Data System (ADS)

    Rivard, Mark Joseph

    Examination of neutron dosimetry for 252Cf has been conducted using calculative and experimental means. Monte Carlo N-Particle (MCNP) transport code was used in a distributed computing environment as a parallel virtual machine (PVM) to determine the absorbed neutron dose and neutron energy spectrum from 252Cf in a variety of clinically relevant materials. Herein, a Maxwellian spectrum was used to model the 252Cf neutron emissions within these materials. 252Cf mixed-field dosimetry of Applicator Tube (AT) type sources was measured using 1.0 and 0.05 cm3 tissue-equivalent ion chambers and a miniature GM counter. A dosimetry protocol was formulated similar that of ICRU 45. The 252Cf AT neutron dosimetry was determined in the cylindrical coordinate system formalism recommended by the AAPM Task Group 43. These results demonstrated the overwhelming dependence of dosimetry on the source geometry factor as there was no significant neutron attenuation within the source or encapsulation. Gold foils and TLDs were used to measure the thermal flux in the vicinity of 252Cf AT sources to compare with the results calculated using MCNP. As the fast neutron energy spectrum did not markedly changed at increasing distances from the AT source, neutron dosimetry results obtained with paired ion chambers using fixed sensitivity factors agreed well with MCNP results and those in the literature. Calculations of moderated 252Cf neutron energy spectrum with various loadings of 10B and 157Gd were performed, in addition to analysis of neutron capture therapy dosimetry with these isotopes. Radiological concerns such as personnel exposure and shielding of 252Cf emissions were examined. Feasibility of a high specific-activity 252Cf HDR source was investigated through radiochemical and metallurgical studies using stand-ins such as Tb, Gd and 249Cf. Issues such as capsule burst strength due to helium production for a variety of proposed HDR sources were addressed. A recommended 252Cf source strength of at least 1mg was necessary for fabrication of a 252Cf HDR source.

  2. 14-MeV Neutron Generator Used as a Thermal Neutron Source

    SciTech Connect

    Dioszegi,I.

    2008-08-10

    One of the most important applications of the general purpose Monte Carlo N-Particle (MCNPS and MCNPX) codes is neutron shielding design. We employed this method to simulate the shield of a 14-MeV neutron generator used as a thermal neutron source providing an external thermal neutron beam for testing large area neutron detectors developed for diffraction studies in biology and also useful for national security applications. Nuclear reactors have been the main sources of neutrons used for scientific applications. In the past decade, however, a large number of reactors have been shut down, and the importance of other, smaller devices capable of providing neutrons for research has increased. At Brookhaven National Laboratory a moderated Am-Be neutron source with shielding is used for neutron detector testing. This source is relatively weak, but provides a constant flux of neutrons, even when not in use. The use of a 14 MeV energized neutron generator, with an order of magnitude higher neutron flux has been considered to replace the Am-Be source, but the higher fast neutron yield requires a more careful design of moderator and shielding. In the present paper we describe a proposed shielding configuration based on Monte Carlo calculations, and provide calculated neutron flux and dose distributions. We simulated the neutron flux distribution of our existing Am-Be source surrounded by a paraffin thermalizer cylinder (radius of 17.8 cm), 0.8 mm cadmium, and borated polyethylene as biological shield. The thermal neutrons are available through a large opening through the polyethylene and cadmium. The geometrical model for the MCNPS and MCNPX2 simulations is shown in Fig. 1. We simulated the Am-Be source neutron energy distribution as a point source having an energy distribution of four discrete lines at 3.0 (37%), 5.0 (35%), 8.0 (20%) and 11.0 (8%) MeV energies. The estimated source strength based on the original specifications is 6.6 {center_dot} 10{sup 6} neutrons/sec. The simulation accurately predicts the measured thermal neutron flux at the collimator (Figure 2), thus providing validation for this method. Using MCNPX we simulated the neutron and photon dose distribution and also obtained a good agreement with the measured values. Having established a validated framework for the shield calculation we then scaled up the Am-Be arrangement to simulate the shielding required for the higher neutron energy and flux of the neutron generator (-10{sup 8} neutrodsec at 14 MeV). Given the physical dimensions of the generator we have chosen a cylindrical geometry, where the generator tube is placed vertically into a cylindrical thermalizer (25 cm paraffin) from above. The thermalizer is surrounded by 0.8 mm cadmium, and a cylindrical borated polyethylene shield. A cylindrical opening (radius of 7.6 cm) serves to direct the neutrons out towards the experimental area (on the right side). The initial model is shown in figure 3. The first goal of the calculations was to establish the minimal required radius of the biological shield. For this purpose we performed MCNPX neutron and photon dose distribution calculations by tallying the absorbed dose on a 200 x 200 cm mesh in the vertical center plane superimposed over the geometry. Figure 4. displays the neutron dose distribution along the central horizontal (X) axis. As observed from the figure, a shielding radius of -80 cm is sufficient to obtain a dose level of < -4 mrem/hour outside the shield (except from the open neutron channel on the right). In the next step we studied the optimization of the thickness of the paraffin thermalizer by increasing the depth of the neutron exit channel into the paraffin cylinder. It was found, that the thermal flux greatly increases if we have thinner paraffin layer, an optimal value being about 5 cm thickness. But as a drawback the flux of fast neutrons also increased. A thicker thermalizer layer, in fact, acts as shielding. A slightly off centered, tangential placement of the neutron channel provides a solution which maximizes the thermal flux to fast n

  3. The new Cold Neutron Chopper Spectrometer at the Spallation Neutron Source -- Design and Performance

    SciTech Connect

    Ehlers, Georg; Podlesnyak, Andrey A.; Niedziela, Jennifer L.; Iverson, Erik B.; Sokol, Paul E.

    2011-01-01

    The design and performance of the new cold neutron chopper spectrometer (CNCS) at the Spallation Neutron Source in Oak Ridge are described. CNCS is a direct-geometry inelastic time-of-flight spectrometer, designed essentially to cover the same energy and momentum transfer ranges as IN5 at ILL, LET at ISIS, DCS at NIST, TOFTOF at FRM-II, AMATERAS at J-PARC, PHAROS at LANSCE, and NEAT at HZB, at similar energy resolution. Measured values of key figures such as neutron flux at sample position and energy resolution are compared between measurements and ray tracing Monte Carlo simulations, and good agreement (better than 20% of absolute numbers) has been achieved. The instrument performs very well in the cold and thermal neutron energy ranges, and promises to become a workhorse for the neutron scattering community for quasielastic and inelastic scattering experiments.

  4. The new cold neutron chopper spectrometer at the Spallation Neutron Source: Design and performance

    SciTech Connect

    Ehlers, G.; Podlesnyak, A. A.; Niedziela, J. L.; Iverson, E. B.; Sokol, P. E.

    2011-08-15

    The design and performance of the new cold neutron chopper spectrometer (CNCS) at the Spallation Neutron Source in Oak Ridge are described. CNCS is a direct-geometry inelastic time-of-flight spectrometer, designed essentially to cover the same energy and momentum transfer ranges as IN5 at ILL, LET at ISIS, DCS at NIST, TOFTOF at FRM-II, AMATERAS at J-PARC, PHAROS at LANSCE, and NEAT at HZB, at similar energy resolution. Measured values of key figures such as neutron flux at sample position and energy resolution are compared between measurements and ray tracing Monte Carlo simulations, and good agreement (better than 20% of absolute numbers) has been achieved. The instrument performs very well in the cold and thermal neutron energy ranges, and promises to become a workhorse for the neutron scattering community for quasielastic and inelastic scattering experiments.

  5. Neutron source design for the Los Alamos APT system

    SciTech Connect

    Cappiello, M.W. )

    1993-01-01

    The Los Alamos National Laboratory accelerator production of tritium (APT) design incorporates a high-energy (1-GeV), high-current (200-mA) proton accelerator, a tungsten neutron source, and a moderating blanket that contains [sup 3]He for the production of tritium. To reduce the power density in the neutron source to acceptable levels, the incident proton beam is expanded to a 0.5- x 1.0-m [open quotes]beam spot.[close quotes] The beam passes through a double-wall vacuum interface window that is constructed of Inconel and is cooled with D[sub 2]O. The protons then enter a 1.3-m-diam x 3.5-m-long vessel also made of Inconel that contains [sup 3]He at moderate pressure (0.66 MPa) and 104 tungsten rod bundles that are distributed along the length of the vessel. The protons impinge on the tungsten and produce high-energy neutrons through the process of spallation. Behind the Inconel vessel is a proton backstop made of zirconium and lead that provides an additional source of neutrons and fully stops the proton beam. The Inconel vessel is surrounded by an annulus of aluminum-clad lead that is cooled with D[sub 2]O. Neutron multiplication occurs in the lead through additional spallation and (n,xn) reactions. Surrounding the lead is a thin annulus of [sup 3]He contained in aluminum tubing, a D[sub 2]O moderator, another annulus of [sup 3]He, and a D[sub 2]O reflector. Neutrons are moderated to near thermal energies in the D[sub 2]O. Tritium is produced through neutron capture in [sup 3]He that is circulated and processed continually. Thermal neutrons that are scattered back into the neutron source are preferentially captured in the [sup 3]He, thereby reducing the parasitic capture in the tungsten. The entire assembly of the neutron source vessel and surrounding blanket of lead, [sup 3]He, and D[sub 2]O are contained in a steel vessel.

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

    PubMed

    Vega-Carrillo, H R; Manzanares-Acuña, E; Hernández-Dávila, V M; Gallego, E; Lorente, A; Donaire, I

    2007-01-01

    A Monte Carlo study to determine the shielding features to neutrons of water-extended polyester was carried out. During calculations, (252)Cf 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 (252)Cf and due to capture gamma rays in the shielding were included. PMID:17496334

  7. Proton Driver Linac for the Frankfurt Neutron Source

    SciTech Connect

    Wiesner, C.; Chau, L. P.; Dinter, H.; Droba, M.; Heilmann, M.; Joshi, N.; Maeder, D.; Metz, A.; Meusel, O.; Noll, D.; Podlech, H.; Ratzinger, U.; Reichau, H.; Schempp, A.; Schmidt, S.; Schweizer, W.; Volk, K.; Wagner, C.; Mueller, I.

    2010-08-04

    The Frankfurt Neutron Source at the Stern-Gerlach-Zentrum (FRANZ) will deliver high neutron fluxes in the energy range of 1 to 500 keV. The Activation Mode provides a high averaged neutron flux created by a cw proton beam of up to 5 mA, while in the Compressor Mode intense neutron pulses of 1 ns length are formed with a repetition rate of up to 250 kHz. The Compressor Mode is well-suited for energy-dependent neutron capture measurements using the Time-of-Flight method in combination with a 4{pi} BaF{sub 2} detector array. The design of the proton driver linac for both operation modes is presented. This includes the volume type ion source, the ExB chopper located in the low energy section, the RFQ-IH combination for beam acceleration and the bunch compressor. Finally, the neutron production at the lithium-7 target and the resulting energy spectrum is described.

  8. Accelerator-based neutron source for boron neutron capture therapy (BNCT) and method

    DOEpatents

    Yoon, Woo Y. (Idaho Falls, ID); Jones, James L. (Idaho Falls, ID); Nigg, David W. (Idaho Falls, ID); Harker, Yale D. (Idaho Falls, ID)

    1999-01-01

    A source for boron neutron capture therapy (BNCT) comprises a body of photoneutron emitter that includes heavy water and is closely surrounded in heat-imparting relationship by target material; one or more electron linear accelerators for supplying electron radiation having energy of substantially 2 to 10 MeV and for impinging such radiation on the target material, whereby photoneutrons are produced and heat is absorbed from the target material by the body of photoneutron emitter. The heavy water is circulated through a cooling arrangement to remove heat. A tank, desirably cylindrical or spherical, contains the heavy water, and a desired number of the electron accelerators circumferentially surround the tank and the target material as preferably made up of thin plates of metallic tungsten. Neutrons generated within the tank are passed through a surrounding region containing neutron filtering and moderating materials and through neutron delimiting structure to produce a beam or beams of epithermal neutrons normally having a minimum flux intensity level of 1.0.times.10.sup.9 neutrons per square centimeter per second. Such beam or beams of epithermal neutrons are passed through gamma ray attenuating material to provide the required epithermal neutrons for BNCT use.

  9. Accelerator-based neutron source for boron neutron capture therapy (BNCT) and method

    DOEpatents

    Yoon, W.Y.; Jones, J.L.; Nigg, D.W.; Harker, Y.D.

    1999-05-11

    A source for boron neutron capture therapy (BNCT) comprises a body of photoneutron emitter that includes heavy water and is closely surrounded in heat-imparting relationship by target material; one or more electron linear accelerators for supplying electron radiation having energy of substantially 2 to 10 MeV and for impinging such radiation on the target material, whereby photoneutrons are produced and heat is absorbed from the target material by the body of photoneutron emitter. The heavy water is circulated through a cooling arrangement to remove heat. A tank, desirably cylindrical or spherical, contains the heavy water, and a desired number of the electron accelerators circumferentially surround the tank and the target material as preferably made up of thin plates of metallic tungsten. Neutrons generated within the tank are passed through a surrounding region containing neutron filtering and moderating materials and through neutron delimiting structure to produce a beam or beams of epithermal neutrons normally having a minimum flux intensity level of 1.0{times}10{sup 9} neutrons per square centimeter per second. Such beam or beams of epithermal neutrons are passed through gamma ray attenuating material to provide the required epithermal neutrons for BNCT use. 3 figs.

  10. Neutron Radiographic Inspection of Industrial Components using Kamini Neutron Source Facility

    SciTech Connect

    Raghu, N.; Anandaraj, V.; Kasiviswanathan, K. V.; Kalyanasundaram, P.

    2008-03-17

    Kamini (Kalpakkam Mini) reactor is a U{sup 233} fuelled, demineralised light water moderated and cooled, beryllium oxide reflected, low power (30 kW) nuclear research reactor. This reactor functions as a neutron source with a flux of 10{sup 12} n/cm{sup 2} s{sup -1} at core centre with facilitates for carrying out neutron radiography, neutron activation analysis and neutron shielding experiments. There are two beam tubes for neutron radiography. The length/diameter ratio of the collimators is about 160 and the aperture size is 220 mmx70 mm. Flux at the outer end of the beam tube is {approx}10{sup 6}-10{sup 7} n/cm{sup 2} s. The north end beam tube is for radiography of inactive object while the south side beam tube is for radiography of radioactive objects. The availability of high neutron flux coupled with good collimated beam provides high quality radiographs with short exposure time. The reactor being a unique national facility for neutron radiography has been utilized in the examination of irradiated components, aero engine turbine blades, riveted plates, automobile chain links and for various types of pyro devices used in the space programme. In this paper, an overview of the salient features of this reactor facility for neutron radiography and our experience in the inspection of a variety of industrial components will be given.

  11. Development and study of a portable plasma focus neutron source

    NASA Astrophysics Data System (ADS)

    Vinogradov, V. P.; Nashilevskii, A. V.; Krauz, V. I.; Remnev, G. E.; Vinogradova, Yu. V.; Kanaev, G. G.; Mitrofanov, K. N.; Myalton, V. V.

    2014-02-01

    The work is devoted to designing a compact pulsed neutron source on the basis of a plasma focus (PF) discharge. The main task was to study the physical processes accompanying a sub-kilojoule repetitive PF discharge. A device with a power supply energy of up to 600 J and pulse repetition rate of up to 10 Hz has been developed and put into operation. The dependence of the neutron yield as a function of the pulse repetition rate has been studied experimentally. A neutron flux of ˜108 neutrons/s has been obtained in the 3-s-long packet mode with a repetition rate of 10 Hz and discharge current of 80-90 kA.

  12. High Flux Isotope Reactor cold neutron source reference design concept

    SciTech Connect

    Selby, D.L.; Lucas, A.T.; Hyman, C.R.

    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.

  13. Augmenting real data with synthetic data: an application in assessing radio-isotope identification algorithms

    SciTech Connect

    Burr, Tom L; Hamada, Michael; Graves, Todd; Myers, Steve

    2008-01-01

    The performance of Radio-Isotope Identification (RIID) algorithms using gamma spectroscopy is increasingly important. For example, sensors at locations that screen for illicit nuclear material rely on isotope identification to resolve innocent nuisance alarms arising from naturally occurring radioactive material. Recent data collections for RIID testing consist of repeat measurements for each of several scenarios to test RIID algorithms. Efficient allocation of measurement resources requires an appropriate number of repeats for each scenario. To help allocate measurement resources in such data collections for RIID algorithm testing, we consider using only a few real repeats per scenario. In order to reduce uncertainty in the estimated RIID algorithm performance for each scenario, the potential merit of augmenting these real repeats with realistic synthetic repeats is also considered. Our results suggest that for the scenarios and algorithms considered, approximately 10 real repeats augmented with simulated repeats will result in an estimate having comparable uncertainty to the estimate based on using 60 real repeats.

  14. A Californium-252 Neutron Source for Student Use

    ERIC Educational Resources Information Center

    Bowen, H. J.

    1975-01-01

    Describes an undergraduate chemistry experiment which utilizes small samples of Californium 252 as a neutron source for the activation of 12 other elements. The students prepare decay curves of the radioactive isotopes and perform nondestructive activation analyses for gram amounts of some elements. (MLH)

  15. Opportunities for Neutrino Physics at the Spallation Neutron Source (SNS)

    SciTech Connect

    Efremenko, Yuri; Hix, William Raphael

    2009-01-01

    In this paper we discuss opportunities for a neutrino program at the Spallation Neutrons Source (SNS) being commissioning at ORNL. Possible investigations can include study of neutrino-nuclear cross sections in the energy rage important for supernova dynamics and neutrino nucleosynthesis, search for neutrino-nucleus coherent scattering, and various tests of the standard model of electro-weak interactions.

  16. Performance of the Intense Pulsed Neutron Source Accelerator System

    SciTech Connect

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

    1986-09-22

    The performance of the Intense Pulsed Neutron Source (IPNS) Accelerator System is reported, including an increase in average beam current to 13.4 microamperes and increased reliability to 93.2%. Brief discussions are given for the performance of the major accelerator subsystems, including the H/sup -/ ion source and preaccelerator, the 50 MeV linac, and the synchrotron and its subsystems. (LEW)

  17. Optimizing moderator dimensions for neutron scattering at the spallation neutron source

    SciTech Connect

    Zhao, J. K.; Robertson, J. L.; Herwig, Kenneth W.; Gallmeier, Franz X.; Riemer, Bernard W.

    2013-12-15

    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)

  18. International workshop on plasma-based neutron sources

    SciTech Connect

    1996-12-09

    The workshop was devoted to discussion of the status and future directions of work on plasma-based neutron sources. The workshop presentations demonstrated significant progress in development of the concepts of these sources and in broadening the required data base. Two main groups of neutron source designs were presented at the workshop: tokamak-based and mirror-based. Designs of the tokamak- based devices use the extensive data base generated during decades of tokamak research. Their plasma physics performance can be predicted with a high degree of confidence. On the other hand, they are relatively large and expensive, and best suited for Volumetric Neutron Sources (VNSes) or other large scale test facilities. They also have the advantage of being on the direct path to a power- producing reactor as presently conceived, although alternatives to the tokamak are presently receiving serious consideration for a reactor. The data base for the mirror-based group of plasma sources is less developed, but they are generally more flexible and, with appropriate selection of parameters, have the potential to be developed as compact Accelerated Test Facilities (ATFs) as well as full-scale VNSes. Also discussed at the workshop were some newly proposed but potentially promising concepts, like those based on the flow-through pinch and electrostatic ion-beam sources.

  19. Material issues relating to high power spallation neutron sources

    NASA Astrophysics Data System (ADS)

    Futakawa, M.

    2015-02-01

    Innovative researches using neutrons are being performed at the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), in which a mercury target system is installed for MW-class pulse spallation neutron sources. In order to produce neutrons by the spallation reaction, proton beams are injected into the mercury target. At the moment, when the intense proton beam hits the target, pressure waves are generated in mercury because of the abrupt heat deposition. The pressure waves interact with the target vessel, leading to negative pressure that may cause cavitation along the vessel wall, i.e. on the interface between liquid and solid metals. On the other hand, the structural materials are subjected to irradiation damage due to protons and neutrons, very high cycle fatigue damages and so-called "liquid metal embrittlement". That is, the structural materials must be said to be exposed to the extremely severe environments. In the paper, research and development relating to the material issues in the high power spallation neutron sources that has been performed so far at J-PARC is summarized.

  20. Experience with position sensitive neutron detectors at the Intense Pulsed Neutron Source

    SciTech Connect

    Crawford, R.K.; Haumann, J.R.; Schultz, A.J.; Felcher, G.P.; Epperson, J.E.; Thiyagarajan, P.; Montague, D.G.; Dejus, R.J.

    1990-05-07

    At the Intense Pulsed Neutron Source (IPNS) pulses of protons accelerated in a synchrotron produce pulses of fast neutrons via the spallation process in an enriched uranium target. After moderation, the resulting pulses of slow neutrons are directed into beams which serve a variety of neutron scattering instruments. Currently there are thirteen neutron scattering instruments in operation or under development at IPNS, and six of these use position-sensitive neutron detectors (PSDs). These PSDs are: a 30 cm {times} 30 cm, {approximately}3 mm resolution, neutron Anger camera area PSD with {sup 6}Li-glass scintillator; a 2.5 cm dia, {approximately}0.7 mm resolution, microchannel-plate area PSD with {sup 6}Li-glass scintillator; a 20 cm {times} 20 cm, {approximately}5 mm resolution, {sup 3}He proportional counter area PSD; a 40 cm {times} 40 cm, {approximately}4 mm resolution, {sup 3}He proportional counter area PSD; a flat 20 cm long, {approximately}1.6 mm resolution, {sup 3}He proportional counter linear PSD; and 160 cylindrical {sup 3}He proportional counter linear PSDs, each of which is 1.27 cm in dia 60 cm long and has {approximately}14 mm resolution. These detectors, in addition to being position-sensitive, resolve the time of the neutron capture with {approximately}1 {mu}s precision for neutron time-of-flight measurements. This paper will discuss these various PSDs with emphasis on the instrumental specifications and the reasons for the selection of the different types of PSDs, and will also discuss the observed performances of these PSDs. 14 refs., 6 figs., 1 tab.

  1. An Overview of the Spallation Neutron Source Project

    E-print Network

    Kustom, R L

    2000-01-01

    The Spallation Neutron Source (SNS) is being designed, constructed, installed and commissioned by the staff of six national laboratories, Argonne National Laboratory, Brookhaven National Laboratory, Jefferson National Accelerator Laboratory, Lawrence Berkeley National Laboratory, Los Alamos National Laboratory, and Oak Ridge National Laboratory. The accelerator systems are designed to deliver a 695 ns proton-pulse onto a mercury target at a 60-Hz repetition rate and an average power of 2-MW. Neutron moderators that will convert the spallation neutrons into slow neutrons for material science research will surround the target. The Front-End systems are designed to generate an H- beam of minipulses, 68% beam on, 32% beam off every 965 ns, at 2.5 MeV for 1 ms, 60 times a second. The Front-End systems include a RF driven, volume-production ion source, beam chopping system, RFQ, and beam transport. The ion source will have to achieve about 65 mA to deliver 52 mA at the input to the linac. The linac consists of a dr...

  2. Accelerator-Driven Neutron Source for Cargo Screening

    SciTech Connect

    Ludewigt, B.A.; Bleuel, D.L.; Hoff, M.D.; Kwan, J.W.; Li, D.; Ratti, A.; Staples, J.W.; Virostek, S.P.; Wells, R.P.

    2006-11-15

    Advanced neutron interrogation systems for the screening ofsea-land cargo containers for shielded special nuclear materials (SNM)require a high-yield neutron source to achieve the desired detectionprobability, false alarm rate, and throughput. An accelerator-drivenneutron source is described that produces a forward directed beam ofhigh-energy (up to 8.5 MeV) neutrons utilizing the D(d,n)3He reaction atdeuteron beam energies of up to 6 MeV. The key components of the neutronsource are a high-current RFQ accelerator and an innovative neutronproduction target. A microwave-driven deuteron source is coupled to anelectrostatic LEBT that injects a 40 mA D+-beam into a 6 MeV, 5.1meter-long, 200 MHz RFQ. The RFQ is based on an unusual beam dynamicsdesign and is capable of operating at a duty factor that produces morethan 1.2 mA timeaverage beam current. The beam is transported to a2-atmosphere deuterium gas target with a specially-designed, thinentrance window. A high-frequency dipole magnet is used to spread thebeam over the long dimension of the 4 by 35 cm target window. The sourcewill be capable of delivering a neutron flux of ~;2 x 107 n/(cm2 x s) tothe center of a sea-land cargo container and is expected t o satisfy therequirements for full testing and demonstration of advanced neutroninterrogation techniques based on stimulated SNM signatures.

  3. Dense Plasma Focus Fusion Neutron Sources Progress at NSTec, September 2011

    SciTech Connect

    Hagen, E. C.

    2011-07-02

    A number of dense plasma focus (DPF) sources are introduced, including their operating characteristics and current activities. Neutron resonance spectroscopy is discussed and the feasibility of using DPF for neutron sources is considered.

  4. Small plasma focus as neutron pulsed source for nuclides identification

    SciTech Connect

    Milanese, M.; Moroso, R.; Barbaglia, M.; Universidad del Centro de la Provincia de Buenos Aires , Pinto 399, Tandil 7000, Buenos Aires ; Niedbalski, J.; Mayer, R.; Castillo, F.

    2013-10-15

    In this paper, we present preliminary results on the feasibility of employing a low energy (2 kJ, 31 kV) plasma focus device as a portable source of pulsed neutron beams (2.45 MeV) generated by nuclear fusion reactions D-D, for the “in situ” analysis of substances by nuclear activation. This source has the relevant advantage of being pulsed at requirement, transportable, not permanently radioactive, without radioactive waste, cheap, among others. We prove the feasibility of using this source showing several spectra of the characteristic emission line for manganese, gold, lead, and silver.

  5. Nuclear science research at the WNR and LANSCE neutron sources

    SciTech Connect

    Lisowski, P.W.

    1994-06-01

    The Weapons Neutron Research (WNR) Facility and the Los Alamos Neutron Scattering Center (LANSCE) use 800 MeV proton beam from the Los Alamos Meson Physics Facility (LAMPF) to generate intense bursts of neutrons. Experiments using time-of-flight (TOF) energy determination can cover an energy range from thermal to about 2 MeV at LANSCE and 0.1 to 800 MeV at WNR. At present, three flight paths at LANSCE and six flight paths at WNR are used in basic and applied nuclear science research. In this paper we present a status report on WNR and LANSCE, discuss plans for the future, and describe three experiments recently completed or underway that use the unique features of these sources.

  6. Magnified Neutron Radiography with Coded Sources

    NASA Astrophysics Data System (ADS)

    Bingham, P.; Santos-Villalobos, H.; Lavrik, N.; Gregor, J.; Bilheux, H.

    A coded source imaging (CSI) system has been developed and tested at the High Flux Isotope Reactor (HFIR) CG-1D beamline at Oak Ridge National Laboratory (ORNL). The goal of this system is to use magnification to improve resolution of the imaging system beyond the detector resolution. For this system, coded masks have been manufactured at 10 ?m resolution with 9 ?m thick Gd patterned on Si wafers, a system model base iterative reconstruction code developed, and experiments have been performed at resolutions of 200 ?m, 100 ?m, 50 ?m, 20 ?m, and 10 ?m with the object place greater than 5.5m from the detector giving magnifications up to 25 times.

  7. Measuring and monitoring KIPT Neutron Source Facility Reactivity

    SciTech Connect

    Cao, Yan; Gohar, Yousry; Zhong, Zhaopeng

    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.

  8. 76 FR 76327 - Installation of Radiation Alarms for Rooms Housing Neutron Sources

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-07

    ... 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....

  9. Post irradiation examination of the Spallation Neutron Source target vessels

    SciTech Connect

    McClintock, David A; Ferguson, Phillip D; Mansur, Louis K

    2010-01-01

    The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is an accelerator-based pulsed neutron source that produces high-energy spallation neutrons by bombarding liquid mercury flowing through a stainless steel target vessel. During operation the proton beam and spallation neutrons produce radiation damage in the AISI 316L austenitic stainless steel target vessel and water-cooled shroud. The beam pulses also cause rapid heating of the liquid mercury, which may produce cavitation erosion damage on the inner surface of the target vessel. The cavitation erosion rate is thought to be highly sensitive to beam power and predicted to be the primary life-limiting factor of target vessel. Though mitigation of cavitation erosion and radiation damage to the target vessel will be a critical for successful high-power operation of the SNS facility, the effects of radiation damage and cavitation erosion to target vessels in liquid metal spallation systems are not well known. Therefore preparations are being undertaken to perform post irradiation examination (PIE) of the liquid mercury target vessel and water-cooled shroud after end-of-life occurs. An overview of the planned PIE for the SNS target vessel is presented here, including proposed techniques for specimen acquisition and subsequent material properties characterization.

  10. Backscattering at a pulsed neutron source, the MUSICAL instrument

    NASA Astrophysics Data System (ADS)

    Alefeld, B.

    1995-02-01

    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 Jülich 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 cryst al (MUSICAL) leads to a very effective instrument, benefitting from the peak flux of the pulsed source.

  11. Dynamics of a self-gravitating neutron source

    SciTech Connect

    Paret, D. Manreza; Martínez, A. Pérez; Rey, A. Ulacia; Sussman, Roberto A. E-mail: aurora@icmf.inf.cu E-mail: sussman@nucleares.unam.mx

    2010-03-01

    We examine the dynamics of a self-gravitating magnetized neutron gas as a source of a Bianchi I spacetime described by the Kasner metric. The set of Einstein-Maxwell field equations can be expressed as a dynamical system in a 4-dimensional phase space. Numerical solutions of this system reveal the emergence of a point-like singularity as the final evolution state for a large class of physically motivated initial conditions. Besides the theoretical interest of studying this source in a fully general relativistic context, the resulting idealized model could be helpful in understanding the collapse of local volume elements of a neutron gas in the critical conditions that would prevail in the center of a compact object.

  12. SPALLATION NEUTRON SOURCE OPERATIONAL EXPERIENCE AT 1 MW

    SciTech Connect

    Galambos, John D

    2011-01-01

    The Spallation Neutron Source (SNS) has been operating at the MW level for about one year. Experience in beam loss control and machine activation at this power level is presented. Also experience with machine protection systems is reviewed, which is critical at this power level. One of the most challenging operational aspects of high power operation has been attaining high availability, which is also discussed

  13. Obsidian sources characterized by neutron-activation analysis.

    PubMed

    Gordus, A A; Wright, G A; Griffin, J B

    1968-07-26

    Concentrations of elements such as manganese, scandium, lanthanum, rubidium, samarium, barium, and zirconium in obsidian samples from different flows show ranges of 1000 percent or more, whereas the variation in element content in obsidian samples from a single flow appears to be less than 40 percent. Neutron-activation analysis of these elements, as well as of sodium and iron, provides a means of identifying the geologic source of an archeological artifact of obsidian. PMID:17776740

  14. Actinide/beryllium neutron sources with reduced dispersion characteristics

    SciTech Connect

    Schulte, Louis D.

    2012-08-14

    Neutron source comprising a composite, said composite comprising crystals comprising BeO and AmBe.sub.13, and an excess of beryllium, wherein the crystals have an average size of less than 2 microns; the size distribution of the crystals is less than 2 microns; and the beryllium is present in a 7-fold to a 75-fold excess by weight of the amount of AmBe.sub.13; and methods of making thereof.

  15. Characterization of nuclear sources from neutron-neutron, proton-proton and neutron-proton correlation functions

    NASA Astrophysics Data System (ADS)

    Ghetti, R.; Mårtensson, J.; Colonna, N.; Helgesson, J.; Jakobsson, B.; De Filippo, E.; Tagliente, G.; Lanzanò, G.; Pantaleo, A.; Bellini, V.; Anzalone, A.; Carlèn, 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.; CHIC Collaboration

    2000-07-01

    Two-neutron, two-proton and neutron-proton correlation functions have been measured simultaneously for the E/ A=45 MeV 58 Ni + 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.

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

    PubMed

    Blue, Thomas E; Yanch, Jacquelyn C

    2003-01-01

    This paper reviews the development of low-energy light ion accelerator-based neutron sources (ABNSs) for the treatment of brain tumors through an intact scalp and skull using boron neutron capture therapy (BNCT). A major advantage of an ABNS for BNCT over reactor-based neutron sources is the potential for siting within a hospital. Consequently, light-ion accelerators that are injectors to larger machines in high-energy physics facilities are not considered. An ABNS for BNCT is composed of: (1) the accelerator hardware for producing a high current charged particle beam, (2) an appropriate neutron-producing target and target heat removal system (HRS), and (3) a moderator/reflector assembly to render the flux energy spectrum of neutrons produced in the target suitable for patient irradiation. As a consequence of the efforts of researchers throughout the world, progress has been made on the design, manufacture, and testing of these three major components. Although an ABNS facility has not yet been built that has optimally assembled these three components, the feasibility of clinically useful ABNSs has been clearly established. Both electrostatic and radio frequency linear accelerators of reasonable cost (approximately 1.5 M dollars) appear to be capable of producing charged particle beams, with combinations of accelerated particle energy (a few MeV) and beam currents (approximately 10 mA) that are suitable for a hospital-based ABNS for BNCT. The specific accelerator performance requirements depend upon the charged particle reaction by which neutrons are produced in the target and the clinical requirements for neutron field quality and intensity. The accelerator performance requirements are more demanding for beryllium than for lithium as a target. However, beryllium targets are more easily cooled. The accelerator performance requirements are also more demanding for greater neutron field quality and intensity. Target HRSs that are based on submerged-jet impingement and the use of microchannels have emerged as viable target cooling options. Neutron fields for reactor-based neutron sources provide an obvious basis of comparison for ABNS field quality. This paper compares Monte Carlo calculations of neutron field quality for an ABNS and an idealized standard reactor neutron field (ISRNF). The comparison shows that with lithium as a target, an ABNS can create a neutron field with a field quality that is significantly better (by a factor of approximately 1.2, as judged by the relative biological effectiveness (RBE)-dose that can be delivered to a tumor at a depth of 6cm) than that for the ISRNF. Also, for a beam current of 10 mA, the treatment time is calculated to be reasonable (approximately 30 min) for the boron concentrations that have been assumed. PMID:12749700

  17. The Advanced Neutron Source research and development plan

    SciTech Connect

    Selby, D.L.

    1992-11-30

    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 {approximately} 330 MW fission power, producing an unprecedented peak thermal flux of > 7 {times} 10{sup 19} M{sup {minus}2} {center_dot} S{sup {minus}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&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&D activities are controlled and (2) a discussion of the individual tasks that have been identified for the R&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.

  18. The Advanced Neutron Source research and development plan

    SciTech Connect

    Selby, D.L.

    1992-11-30

    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 [approximately] 330 MW fission power, producing an unprecedented peak thermal flux of > 7 [times] 10[sup 19] M[sup [minus]2] [center dot] S[sup [minus]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 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 D activities are controlled and (2) a discussion of the individual tasks that have been identified for the R 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.

  19. The advanced neutron source research and development plan

    SciTech Connect

    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.

  20. Computational Benchmark Calculations Relevant to the Neutronic Design of the Spallation Neutron Source (SNS)

    SciTech Connect

    Gallmeier, F.X.; Glasgow, D.C.; Jerde, E.A.; Johnson, J.O.; Yugo, J.J.

    1999-11-14

    The Spallation Neutron Source (SNS) will provide an intense source of low-energy neutrons for experimental use. The low-energy neutrons are produced by the interaction of a high-energy (1.0 GeV) proton beam on a mercury (Hg) target and slowed down in liquid hydrogen or light water moderators. Computer codes and computational techniques are being benchmarked against relevant experimental data to validate and verify the tools being used to predict the performance of the SNS. The LAHET Code System (LCS), which includes LAHET, HTAPE ad HMCNP (a modified version of MCNP version 3b), have been applied to the analysis of experiments that were conducted in the Alternating Gradient Synchrotron (AGS) facility at Brookhaven National Laboratory (BNL). In the AGS experiments, foils of various materials were placed around a mercury-filled stainless steel cylinder, which was bombarded with protons at 1.6 GeV. Neutrons created in the mercury target, activated the foils. Activities of the relevant isotopes were accurately measured and compared with calculated predictions. Measurements at BNL were provided in part by collaborating scientists from JAERI as part of the AGS Spallation Target Experiment (ASTE) collaboration. To date, calculations have shown good agreement with measurements.

  1. Liquid Li based neutron source for BNCT and science application.

    PubMed

    Horiike, H; Murata, I; Iida, T; Yoshihashi, S; Hoashi, E; Kato, I; Hashimoto, N; Kuri, S; Oshiro, S

    2015-12-01

    Liquid lithium (Li) is a candidate material for a target of intense neutron source, heat transfer medium in space engines and charges stripper. For a medical application of BNCT, epithermal neutrons with least energetic neutrons and ?-ray are required so as to avoid unnecessary doses to a patient. This is enabled by lithium target irradiated by protons at 2.5MeV range, with utilizing the threshold reaction of (7)Li(p,n)(7)Be at 1.88MeV. In the system, protons at 2.5MeV penetrate into Li layer by 0.25mm with dissipating heat load near the surface. To handle it, thin film flow of high velocity is important for stable operation. For the proton accelerator, electrostatic type of the Schnkel or the tandem is planned to be employed. Neutrons generated at 0.6MeV are gently moderated to epithermal energy while suppressing accompanying ?-ray minimum by the dedicated moderator assembly. PMID:26253274

  2. Methods for lipid nanostructure investigation at neutron and synchrotron sources

    NASA Astrophysics Data System (ADS)

    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. Neutron source in the MCNPX shielding calculating for electron accelerator driven facility

    SciTech Connect

    Zhong, Z.; Gohar, Y.

    2012-07-01

    Argonne National Laboratory (ANL) of USA and Kharkov Inst. of Physics and Technology (KIPT) of Ukraine have been collaborating on the design development of an experimental neutron source facility. It is an accelerator driven system (ADS) utilizing a subcritical assembly driven by electron accelerator. The facility will be utilized for performing basic and applied nuclear researches, producing medical isotopes, and training young nuclear specialists. Monte Carlo code MCNPX has been utilized as a design tool due to its capability to transport electrons, photons, and neutrons at high energies. However the facility shielding calculations with MCNPX need enormous computational resources and the small neutron yield per electron makes sampling difficulty for the Monte Carlo calculations. A method, based on generating and utilizing neutron source file, was proposed and tested. This method reduces significantly the required computer resources and improves the statistics of the calculated neutron dose outside the shield boundary. However the statistical errors introduced by generating the neutron source were not directly represented in the results, questioning the validity of this methodology, because an insufficiently sampled neutron source can cause error on the calculated neutron dose. This paper presents a procedure for the validation of the generated neutron source file. The impact of neutron source statistic on the neutron dose is examined by calculating the neutron dose as a function of the number of electron particles used for generating the neutron source files. When the value of the calculated neutron dose converges, it means the neutron source has scored sufficient records and statistic does not have apparent impact on the calculated neutron dose. In this way, the validity of neutron source and the shield analyses could be verified. (authors)

  4. A Permanent-Magnet Microwave Ion Source for a Compact High-Yield Neutron Generator

    E-print Network

    A Permanent-Magnet Microwave Ion Source for a Compact High-Yield Neutron Generator O. Waldmanna-yield compact neutron generator for active interrogation applications. The sealed tube generator will be capable with an optimized magnetic field. Keywords: Neutron generator, Microwave ion source, Active interroga- tion PACS: 29

  5. DESIGN OPTIMIZATION AND THE PATH TOWARDS A 2 MW SPALLATION NEUTRON SOURCE.

    SciTech Connect

    WEI,J.; BLASKIEWICZ,M.; CATALAN-LASHERAS,N.; DAVINO,D.; FEDOTOV,A.; LEE,Y.Y.; MALITSKY,N.; ET AL

    2001-06-18

    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.

  6. Tomsk Polytechnic University cyclotron as a source for neutron based cancer treatment

    SciTech Connect

    Lisin, V. A.; Tomsk Polytechnic University, 30 Lenina av., Tomsk 634050 ; Bogdanov, A. V.; Golovkov, V. M.; Sukhikh, L. G.; Verigin, D. A.; Musabaeva, L. I.

    2014-02-15

    In this paper we present our cyclotron based neutron source with average energy 6.3 MeV generated during the 13.6 MeV deuterons interactions with beryllium target, neutron field dosimetry, and dosimetry of attendant gamma fields. We also present application of our neutron source for cancer treatment.

  7. A Search for Point Sources of EeV Neutrons

    NASA Astrophysics Data System (ADS)

    Pierre Auger Collaboration; Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Anti?i'c, T.; Aramo, C.; Arganda, E.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Badescu, A. M.; Balzer, M.; Barber, K. B.; Barbosa, A. F.; Bardenet, R.; Barroso, S. L. C.; Baughman, B.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellétoile, A.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Bohá?ová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Bruijn, R.; Buchholz, P.; Bueno, A.; Buroker, L.; Burton, R. E.; Caballero-Mora, K. S.; Caccianiga, B.; Caramete, L.; Caruso, R.; Castellina, A.; Catalano, O.; Cataldi, G.; Cazon, L.; Cester, R.; Chauvin, J.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chirinos Diaz, J.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cook, H.; Cooper, M. J.; Coppens, J.; Cordier, A.; Coutu, S.; Covault, C. E.; Creusot, A.; Criss, A.; Cronin, J.; Curutiu, A.; Dagoret-Campagne, S.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; De Donato, C.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; del Peral, L.; del Río, M.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Dutan, I.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fick, B.; Figueira, J. M.; Filevich, A.; Filip?i?, A.; Fliescher, S.; Fracchiolla, C. E.; Fraenkel, E. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Gascon Bravo, A.; Gemmeke, H.; Ghia, P. L.; Giller, M.; Gitto, J.; Glass, H.; Gold, M. S.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gouffon, P.; Grashorn, E.; Grebe, S.; Griffith, N.; Grigat, M.; Grillo, A. F.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hojvat, C.; Hollon, N.; Holmes, V. C.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Ionita, F.; Italiano, A.; Jansen, S.; Jarne, C.; Jiraskova, S.; Josebachuili, M.; Kadija, K.; Kampert, K. H.; Karhan, P.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kelley, J. L.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Koang, D.-H.; Kotera, K.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kulbartz, J. K.; Kunka, N.; La Rosa, G.; Lachaud, C.; LaHurd, D.; Latronico, L.; Lauer, R.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Macolino, C.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, J.; Marin, V.; Maris, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mazur, P. O.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Mertsch, P.; Meurer, C.; Meyhandan, R.; Mi'canovi'c, S.; Micheletti, M. I.; Minaya, I. A.; Miramonti, L.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, E.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nhung, P. T.; Niechciol, M.; Niemietz, L.; Nierstenhoefer, N.; Nitz, D.; Nosek, D.; Nožka, L.; Oehlschläger, J.; Olinto, A.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parizot, E.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; Pe?ala, J.; Pelayo, R.

    2012-12-01

    A thorough search of the sky exposed at the Pierre Auger Cosmic Ray Observatory reveals no statistically significant excess of events in any small solid angle that would be indicative of a flux of neutral particles from a discrete source. The search covers from -90° to +15° in declination using four different energy ranges above 1 EeV (1018 eV). The method used in this search is more sensitive to neutrons than to photons. The upper limit on a neutron flux is derived for a dense grid of directions for each of the four energy ranges. These results constrain scenarios for the production of ultrahigh energy cosmic rays in the Galaxy.

  8. BEAM DUMP WINDOW DESIGN FOR THE SPALLATION NEUTRON SOURCE.

    SciTech Connect

    RAPARIA,D.RANK,J.MURDOCH,G.ET AL.

    2004-03-10

    The Spallation Neutron Source accelerator systems will provide a 1 GeV, 1.44 MW proton beam to a liquid mercury target for neutron production. Beam tuning dumps are provided at the end of the linac (the Linac Dump) and in the Ring-to-Target transport line (the Extraction Dump) [1]. Thin windows are required to separate the accelerator vacuum from the poor vacuum upstream of the beam dump. There are several challenging engineering issues that have been addressed in the window design. Namely, handling of the high local power density deposited by the stripped electrons from the H-beam accelerated in the linac, and the need for low-exposure removal and replacement of an activated window. The thermal design of the linac dump window is presented, as is the design of a vacuum clamp and mechanism that allows remote removal and replacement of the window.

  9. Modeling of water radiolysis at spallation neutron sources

    SciTech Connect

    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 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.

  10. The continued development of the Spallation Neutron Source external antenna H- ion source.

    PubMed

    Welton, R F; Carmichael, J; Desai, N J; Fuga, R; Goulding, R H; Han, B; Kang, Y; Lee, S W; Murray, S N; Pennisi, T; Potter, K G; Santana, M; Stockli, M P

    2010-02-01

    The U.S. Spallation Neutron Source (SNS) is an accelerator-based, pulsed neutron-scattering facility, currently in the process of ramping up neutron production. In order to ensure that the SNS will meet its operational commitments as well as provide for future facility upgrades with high reliability, we are developing a rf-driven, H(-) ion source based on a water-cooled, ceramic aluminum nitride (AlN) plasma chamber. To date, early versions of this source have delivered up to 42 mA to the SNS front end and unanalyzed beam currents up to approximately 100 mA (60 Hz, 1 ms) to the ion source test stand. This source was operated on the SNS accelerator from February to April 2009 and produced approximately 35 mA (beam current required by the ramp up plan) with availability of approximately 97%. During this run several ion source failures identified reliability issues, which must be addressed before the source re-enters production: plasma ignition, antenna lifetime, magnet cooling, and cooling jacket integrity. This report discusses these issues, details proposed engineering solutions, and notes progress to date. PMID:20192396

  11. The RF system for the National Spallation Neutron Source linac

    SciTech Connect

    Tallerico, P.; Billen, J.; Jason, A.

    1997-06-01

    The National Spallation Neutron Source (NSNS) system has been proposed to dramatically improve the neutron capabilities for science applications in the US. The NSNS is a fast pulse neutron source that would consist of a 1000 MeV H-linac, an accumulator ring, a neutron target, and an experimental area. Although the NSNS is to be built at Oak Ridge, the design responsibility is delegated to five US national laboratories, and the Los Alamos National Laboratory is responsible for the linac portion of this machine, from the output of the radio frequency quadrupole (RFQ) accelerator, to the entrance to the accumulator ring. In the baseline design, a total of 59 klystrons are used to provide the RF power for a 1-MW average power beam in the accumulator ring, and a 1.04 ms pulse length, 6.24% duty factor beam in the linac. The frequencies chosen are 402.5 MHz for the RFQ and drift tube linac (DTL) portions of the machine, and 805 MHz for the coupled-cavity DTL (CCDTL) and coupled cavity (CCL) portions of the linac. The baseline 805 MHz klystron is capable of 2.5 MW peak power into a flat load, and it contains a modulating anode. The backup 805 MHz klystron is cathode pulsed, and has a 5 MW peak output power. The modulators for these two klystrons are vastly different. The challenges and compromises for the two klystrons and their associated modulators and RF systems are discussed. The baseline design RF system is presented in detail.

  12. Spallation neutron source saddle antenna H{sup -} ion source project

    SciTech Connect

    Dudnikov, Vadim; Johnson, Rolland P.; Dudnikova, Galina; Stockli, Martin; Welton, Robert

    2010-02-15

    In this project we are developing an H{sup -} source which will synthesize the most important developments in the field of negative ion sources to provide high current, high brightness, good lifetime, high reliability, and high power efficiency. We describe two planned modifications to the present spallation neutron source external antenna source in order to increase the plasma density near the output aperture: (1) replacing the present 2 MHz plasma-forming solenoid antenna with a 13 MHz saddle-type antenna and (2) replacing the permanent multicusp magnetic system with a weaker electromagnet.

  13. Novel Large Area High Resolution Neutron Detector for the Spallation Neutron Source

    SciTech Connect

    Lacy, Jeffrey L

    2009-05-22

    Neutron scattering is a powerful technique that is critically important for materials science and structural biology applications. The knowledge gained from past developments has resulted in far-reaching advances in engineering, pharmaceutical and biotechnology industries, to name a few. New facilities for neutron generation at much higher flux, such as the SNS at Oak Ridge, TN, will greatly enhance the capabilities of neutron scattering, with benefits that extend to many fields and include, for example, development of improved drug therapies and materials that are stronger, longer-lasting, and more impact-resistant. In order to fully realize this enhanced potential, however, higher neutron rates must be met with improved detection capabilities, particularly higher count rate capability in large size detectors, while maintaining practicality. We have developed a neutron detector with the technical and economic advantages to accomplish this goal. This new detector has a large sensitive area, offers 3D spatial resolution, high sensitivity and high count rate capability, and it is economical and practical to produce. The proposed detector technology is based on B-10 thin film conversion of neutrons in long straw-like gas detectors. A stack of many such detectors, each 1 meter in length, and 4 mm in diameter, has a stopping power that exceeds that of He-3 gas, contained at practical pressures within an area detector. With simple electronic readout methods, straw detector arrays can provide spatial resolution of 4 mm FWHM or better, and since an array detector of such form consists of several thousand individual elements per square meter, count rates in a 1 m^2 detector can reach 2?10^7 cps. Moreover, each individual event can be timetagged with a time resolution of less than 0.1 ?sec, allowing accurate identification of neutron energy by time of flight. Considering basic elemental cost, this novel neutron imaging detector can be commercially produced economically, probably at a small fraction of the cost of He-3 detectors. In addition to neutron scattering science, the fully developed base technology can be used as a rugged, low-cost neutron detector in area monitoring and surveying. Radiation monitors are used in a number of other settings for occupational and environmental radiation safety. Such a detector can also be used in environmental monitoring and remote nuclear power plant monitoring. For example, the Department of Energy could use it to characterize nuclear waste dumps, coordinate clean-up efforts, and assess the radioactive contaminants in the air and water. Radiation monitors can be used to monitor the age and component breakdown of nuclear warheads and to distinguish between weapons and reactor grade plutonium. The UN's International Atomic Energy Agency (IAEA) uses radiation monitors for treaty verification, remote monitoring, and enforcing the non-proliferation of nuclear weapons. As part of treaty verification, monitors can be used to certify the contents of containers during inspections. They could be used for portal monitoring to secure border checkpoints, sea ports, air cargo centers, public parks, sporting venues, and key government buildings. Currently, only 2% of all sea cargo shipped is inspected for radiation sources. In addition, merely the presence of radiation is detected and nothing is known about the radioactive source until further testing. The utilization of radiation monitors with neutron sensitivity and capability of operation in hostile port environments would increase the capacity and effectiveness of the radioactive scanning processes.

  14. Nuclear Material Detection by One-Short-Pulse-Laser-Driven Neutron Source

    SciTech Connect

    Favalli, Andrea; Aymond, F.; Bridgewater, Jon S.; Croft, Stephen; Deppert, O.; Devlin, Matthew James; Falk, Katerina; Fernandez, Juan Carlos; Gautier, Donald Cort; Gonzales, Manuel A.; Goodsell, Alison Victoria; Guler, Nevzat; Hamilton, Christopher Eric; Hegelich, Bjorn Manuel; Henzlova, Daniela; Ianakiev, Kiril Dimitrov; Iliev, Metodi; Johnson, Randall Philip; Jung, Daniel; Kleinschmidt, Annika; Koehler, Katrina Elizabeth; Pomerantz, Ishay; Roth, Markus; Santi, Peter Angelo; Shimada, Tsutomu; Swinhoe, Martyn Thomas; Taddeucci, Terry Nicholas; Wurden, Glen Anthony; Palaniyappan, Sasikumar; McCary, E.

    2015-01-28

    Covered in the PowerPoint presentation are the following areas: Motivation and requirements for active interrogation of nuclear material; laser-driven neutron source; neutron diagnostics; active interrogation of nuclear material; and, conclusions, remarks, and future works.

  15. Neutron total cross section measurements of gold and tantalum at the nELBE photoneutron source

    E-print Network

    Hannaske, Roland; Beyer, Roland; Junghans, Arnd; Bemmerer, Daniel; Birgersson, Evert; Ferrari, Anna; Grosse, Eckart; Kempe, Mathias; Kögler, Toni; Marta, Michele; Massarczyk, Ralph; Matic, Andrija; Schramm, Georg; Schwengner, Ronald; Wagner, Andreas

    2013-01-01

    Neutron total cross sections of $^{197}$Au and $^\\text{nat}$Ta have been measured at the nELBE photoneutron source in the energy range from 0.1 - 10 MeV with a statistical uncertainty of up to 2 % and a total systematic uncertainty of 1 %. This facility is optimized for the fast neutron energy range and combines an excellent time structure of the neutron pulses (electron bunch width 5 ps) with a short flight path of 7 m. Because of the low instantaneous neutron flux transmission measurements of neutron total cross sections are possible, that exhibit very different beam and background conditions than found at other neutron sources.

  16. Materials Selection for the HFIR Cold Neutron Source

    SciTech Connect

    Farrell, K.

    2001-08-24

    In year 2002 the High Flux Isotope Reactor (HFIR) will be fitted with a source of cold neutrons to upgrade and expand its existing neutron scattering facilities. The in-reactor components of the new source consist of a moderator vessel containing supercritical hydrogen gas moderator at a temperature of 20K and pressure of 15 bar, and a surrounding vacuum vessel. They will be installed in an enlarged beam tube located at the site of the present horizontal beam tube, HB-4; which terminates within the reactor's beryllium reflector. These components must withstand exceptional service conditions. This report describes the reasons and factors underlying the choice of 6061-T6 aluminum alloy for construction of the in-reactor components. The overwhelming considerations are the need to minimize generation of nuclear heat and to remove that heat through the flowing moderator, and to achieve a minimum service life of about 8 years coincident with the replacement schedule for the beryllium reflector. 6061-T6 aluminum alloy offers the best combination of low nuclear heating, high thermal conductivity, good fabricability, compatibility with hydrogen, superior cryogenic properties, and a well-established history of satisfactory performance in nuclear environments. These features are documented herein. An assessment is given of the expected performance of each component of the cold source.

  17. On-Site Inspection RadioIsotopic Spectroscopy (Osiris) System Development

    SciTech Connect

    Caffrey, Gus J.; Egger, Ann E.; Krebs, Kenneth M.; Milbrath, B. D.; Jordan, D. V.; Warren, G. A.; Wilmer, N. G.

    2015-09-01

    We have designed and tested hardware and software for the acquisition and analysis of high-resolution gamma-ray spectra during on-site inspections under the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The On-Site Inspection RadioIsotopic Spectroscopy—Osiris—software filters the spectral data to display only radioisotopic information relevant to CTBT on-site inspections, e.g.,132I. A set of over 100 fission-product spectra was employed for Osiris testing. These spectra were measured, where possible, or generated by modeling. The synthetic test spectral compositions include non-nuclear-explosion scenarios, e.g., a severe nuclear reactor accident, and nuclear-explosion scenarios such as a vented underground nuclear test. Comparing its computer-based analyses to expert visual analyses of the test spectra, Osiris correctly identifies CTBT-relevant fission product isotopes at the 95% level or better.The Osiris gamma-ray spectrometer is a mechanically-cooled, battery-powered ORTEC Transpec-100, chosen to avoid the need for liquid nitrogen during on-site inspections. The spectrometer was used successfully during the recent 2014 CTBT Integrated Field Exercise in Jordan. The spectrometer is controlled and the spectral data analyzed by a Panasonic Toughbook notebook computer. To date, software development has been the main focus of the Osiris project. In FY2016-17, we plan to modify the Osiris hardware, integrate the Osiris software and hardware, and conduct rigorous field tests to ensure that the Osiris system will function correctly during CTBT on-site inspections. The planned development will raise Osiris to technology readiness level TRL-8; transfer the Osiris technology to a commercial manufacturer, and demonstrate Osiris to potential CTBT on-site inspectors.

  18. A compact neutron generator using a field ionization source

    SciTech Connect

    Persaud, Arun; Waldmann, Ole; Kapadia, Rehan; Takei, Kuniharu; Javey, Ali; Schenkel, Thomas

    2011-10-31

    Field ionization as a means to create ions for compact and rugged neutron sources is pursued. Arrays of carbon nano-#12;bers promise the high #12;eld-enhancement factors required for efficient field ionization. We report on the fabrication of arrays of #12;field emitters with a density up to 10{sup 6} tips/cm{sup 2} and measure their performance characteristics using electron field emission. The critical issue of uniformity is discussed, as are efforts towards coating the nano-fibers to enhance their lifetime and surface properties.

  19. STUDY OF A 10-MW CONTINUOUS SPALLATION NEUTRON SOURCE.

    SciTech Connect

    RUGGIERO,A.G.LUDEWIG,H.SHAPIRO,S.

    2003-05-12

    This paper reports on the feasibility study of a proton Super-Conducting Linac as the driver for an Accelerator-based Continuous Neutron Source (ACNS) [1] to be located at Brookhaven National Laboratory (BNL). The Linac is to be operated in the Continuous Wave (CW) mode to produce an average 10 MW of beam power. The Linac beam energy is taken to be 1.25 GeV. The required average proton beam intensity in exit is then 8 mA.

  20. Advanced Neutron Source (ANS) Project. Progress report FY 1993

    SciTech Connect

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

    1994-01-01

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

  1. Area radiation monitor at the intense pulsed-neutron source

    SciTech Connect

    Eichholz, J.J.; Lynch, F.J.; Mundis, R.L.; Howe, M.L.; Dolecek, E.H.

    1981-01-01

    A tissue-equivalent ionization chamber with associated circuitry has been developed for area radiation monitoring in the Intense Pulsed-Neutron Source (IPNS) facility at Argonne National Laboratory. The conventional chamber configuration was modified in order to increase the electric field and effective volume thereby achieving higher sensitivity and linearity. The instrument provides local and remote radiation level indications and a high level alarm. Twenty-four of these instruments were fabricated for use at various locations in the experimental area of the IPNS-1 facility.

  2. Spallation Neutron Source Beam Dump Radiation Shielding Analysis

    SciTech Connect

    Johnson, J.O.

    2000-02-21

    Preliminary shielding calculations were performed to establish the dimensions of the radiation shielding surrounding the three Spallation Neutron Source (SNS) beam stops. Steel shielding thicknesses were sized to give dose levels of 1, 2, and 5 mrem/h at the top of the shield, and, to provide enough shielding along the sides and bottom of the beam dump so that soil activation is not a problem. It was concluded that 144 in. of steel shielding is needed above the beam stop. The thickness of the concrete floor in the service building above the dump was not a part of these calculations. This shielding design is current as of January 2000.

  3. Neutron source capability assessment for cumulative fission yields measurements

    SciTech Connect

    Descalle, M A; Dekin, W; Kenneally, J

    2011-04-06

    A recent analysis of high-quality cumulative fission yields data for Pu-239 published in the peer-reviewed literature showed that the quoted experimental uncertainties do not allow a clear statement on how the fission yields vary as a function of energy. [Prussin2009] To make such a statement requires a set of experiments with well 'controlled' and understood sources of experimental errors to reduce uncertainties as low as possible, ideally in the 1 to 2% range. The Inter Laboratory Working Group (ILWOG) determined that Directed Stockpile Work (DSW) would benefit from an experimental program with the stated goal to reduce the measurement uncertainties significantly in order to make a definitive statement of the relationship of energy dependence to the cumulative fission yields. Following recent discussions between Lawrence Livermore National Laboratory (LLNL) and Los Alamos National Laboratory (LANL), there is a renewed interest in developing a concerted experimental program to measure fission yields in a neutron energy range from thermal energy (0.025 eV) to 14 MeV with an emphasis on discrete energies from 0.5 to 4 MeV. Ideally, fission yields would be measured at single energies, however, in practice there are only 'quasi-monoenergetic' neutrons sources of finite width. This report outlines a capability assessment as of June 2011 of available neutron sources that could be used as part of a concerted experimental program to measure cumulative fission yields. In a framework of international collaborations, capabilities available in the United States, at the Atomic Weapons Establishment (AWE) in the United Kingdom and at the Commissariat Energie Atomique (CEA) in France are listed. There is a need to develop an experimental program that will reduce the measurement uncertainties significantly in order to make a definitive statement of the relationship of energy dependence to the cumulative fission yields. Fission and monoenergetic neutron sources are available that could support these fission yield experiments in the US, as well as at AWE and CEA. Considerations that will impact the final choice of experimental venues are: (1) Availability during the timeframe of interest; (2) Ability to accommodate special nuclear materials; (3) Cost; (4) Availability of counting facilities; and (5) Expected experimental uncertainties.

  4. SPALLATION NEUTRON SOURCE RING-DESIGN AND CONSTRUCTION SUMMARY.

    SciTech Connect

    WEI,J.

    2005-05-16

    After six years, the delivery of components for the Spallation Neutron Source (SNS) accumulator ring (AR) and the transport lines was completed in Spring 2005. Designed to deliver 1.5 MW beam power (1.5 x 10{sup 14} protons of 1 GeV kinetic energy at a repetition rate of 60 Hz), stringent measures were implemented in the fabrication, test, and assembly to ensure the quality of the accelerator systems. This paper summarizes the design, R&D, and construction of the ring and transport systems.

  5. Materials Consideration for the National Spallation Neutron Source Target

    SciTech Connect

    Mansur, LK

    2001-08-01

    The National Spallation Neutron Source (NSNS), in which neutrons are generated by bombarding a liquid mercury target with 1 GeV protons, will place extraordinary demands on materials performance. The target structural material will operate in an aggressive environment, subject to intense fluxes of high energy protons, neutrons, and other particles, while exposed to liquid mercury and to water. Components that require special consideration include the Hg liquid target container and protective shroud, beam windows, support structures, moderator containers, and beam tubes. In response to these demands a materials R and D program has been developed for the NSNS that includes: selection of materials; calculations of radiation damage; irradiations, post-irradiation testing, and characterization; compatibility testing and characterization; design and implementation of a plan for monitoring of materials performance in service; and materials engineering and technical support to the project. Irradiations are being carried out in actual and simulated spallation environments. Compatibility experiments in Hg are underway to ascertain whether the phenomena of liquid metal embrittlement and temperature gradient mass transfer will be significant. Results available to date are assessed in terms of the design and operational performance of the facility.

  6. Materials considerations for the National Spallation Neutron Source target

    SciTech Connect

    Mansur, L.K.; DiStefano, J.R.; Farrell, K.; Lee, E.H.; Pawel, S.J.; Wechsler, M.S.

    1997-08-01

    The National Spallation Neutron Source (NSNS), in which neutrons are generated by bombarding a liquid mercury target with 1 GeV protons, will place extraordinary demands on materials performance. The target structural material will operate in an aggressive environment, subject to intense fluxes of high energy protons, neutrons, and other particles, while exposed to liquid mercury and to water. Components that require special consideration include the Hg liquid target container and protective shroud, beam windows, support structures, moderator containers, and beam tubes. In response to these demands a materials R and D program has been developed for the NSNS that includes: selection of materials; calculations of radiation damage; irradiations, post irradiation testing, and characterization; compatibility testing and characterization; design and implementation of a plan for monitoring of materials performance in service; and materials engineering and technical support to the project. Irradiations are being carried out in actual and simulated spallation environments. Compatibility experiments in Hg are underway to ascertain whether the phenomena of liquid metal embrittlement and temperature gradient mass transfer will be significant. Results available to date are assessed in terms of the design and operational performance of the facility.

  7. Carbon Nanotube Based Deuterium Ion Source for Improved Neutron Generators

    SciTech Connect

    Fink, R. L.; Jiang, N.; Thuesen, L.; Leung, K. N.; Antolak, A. J.

    2009-03-10

    Field ionization uses high electric fields to cause the ionization and emission of ions from the surface of a sharp electrode. We are developing a novel field ionization neutron generator using carbon nanotubes (CNT) to produce the deuterium ion current. The generator consists of three major components: a deuterium ion source made of carbon nanotubes, a smooth negatively-biased target electrode, and a secondary electron suppression system. When a negative high voltage is applied on the target electrode, a high gradient electric field is formed at the tips of the carbon nanotubes. This field is sufficiently strong to create deuterium (D) ions at or near the nanotubes which are accelerated to the target causing D-D reactions to occur and the production of neutrons. A cross magnetic field is used to suppress secondary emission electrons generated on the target surface. We have demonstrated field ionization currents of 70 nA (1 {mu}A/cm{sup 2}) at hydrogen gas pressure of 10 mTorr. We have found that the current scales proportionally with CNT area and also with the gas pressure in the range of 1 mTorr to 10 mTorr. We have demonstrated pulse cut-off times as short as 2 {mu}sec. Finally, we have shown the feasibility of generating neutrons using deuterium gas.

  8. Generalization of the analytical solution of neutron point kinetics equations with time-dependent external source

    NASA Astrophysics Data System (ADS)

    Seidi, M.; Behnia, S.; Khodabakhsh, R.

    2014-09-01

    Point reactor kinetics equations with one group of delayed neutrons in the presence of the time-dependent external neutron source are solved analytically during the start-up of a nuclear reactor. Our model incorporates the random nature of the source and linear reactivity variation. We establish a general relationship between the expectation values of source intensity and the expectation values of neutron density of the sub-critical reactor by ignoring the term of the second derivative for neutron density in neutron point kinetics equations. The results of the analytical solution are in good agreement with the results obtained with numerical solution.

  9. Status report on the cold neutron source of the Garching neutron research facility FRM-II

    NASA Astrophysics Data System (ADS)

    Gobrecht, K.; Gutsmiedl, E.; Scheuer, A.

    2002-01-01

    The new high flux research reactor of the Technical University of Munich (Technische Universität München, TUM) will be equipped with a cold neutron source (CNS). The centre of the CNS will be located in the D 2O-reflector tank at 400 mm from the reactor core axis close to the thermal neutron flux maximum. The power of 4500 W developed by the nuclear heating in the 16 l of liquid deuterium at 25 K, and in the structures, is evacuated by a two-phase thermal siphon avoiding film boiling and flooding. The thermal siphon is a single tube with counter current flow. It is inclined by 10° from vertical, and optimised for a deuterium flow rate of 14 g/s. Optimisation of structure design and material, as well as safety aspects will be discussed. Those parts of the structure, which are exposed to high thermal neutron flux, are made from Zircaloy 4 and 6061T6 aluminium. Structure failure due to embrittlement of the structure material under high rapid neutron flux is very improbable during the lifetime of the CNS (30 years). Double, in pile even triple, containment with inert gas liner guarantees lack of explosion risk and of tritium contamination to the environment. Adding a few percent of hydrogen (H 2) to the deuterium (D 2) will improve the moderating properties of our relatively small moderator volume. Nearly all of the hydrogen is bound in the form of HD molecules. A long-term change of the hydrogen content in the deuterium is avoided by storing the mixture not in a gas buffer volume but as a metal hydride at low pressure. The metal hydride storage system contains two getter beds, one with 250 kg of LaCo 3Ni 2, the other one with 150 kg of ZrCo 0.8Ni 0.2. Each bed can take the total gas inventory, both beds together can absorb the total gas inventory in <6 min at a pressure <3 bar. The new reactor will have 13 beam tubes, 4 of which are looking at the CNS, including two for very cold (VCN) and ultra-cold neutron (UCN) production. The latter will take place in the horizontal beam tube SR4, which will house an additional cryogenic moderator (e.g. solid deuterium). More than 60% of the experiments foreseen in the new neutron research facility will use cold neutrons from the CNS. The mounting of the hardware components of the CNS into the reactor has started in the spring of 2000. The CNS went into trial operation in the end of year 2000.

  10. Detection of buried explosives using portable neutron sources with nanosecond timing.

    PubMed

    Kuznetsov, A V; Evsenin, A V; Gorshkov, I Yu; Osetrov, O I; Vakhtin, D N

    2004-07-01

    Significant reduction of time needed to identify hidden explosives and other hazardous materials by the "neutron in, gamma out" method has been achieved by introducing timed (nanosecond) neutron sources-the so-called nanosecond neutron analysis technique. Prototype mobile device for explosives' detection based on a timed (nanosecond) isotopic (252)Cf neutron source has been created. The prototype is capable of identifying 400 g of hidden explosives in 10 min. Tests have been also made with a prototype device using timed (nanosecond) neutron source based on a portable D-T neutron generator with built-in segmented detector of accompanying alpha-particles. The presently achieved intensity of the neutron generator is 5x10(7)n/s into 4pi, with over 10(6) of these neutrons being correlated with alpha-particles detected by the built-in alpha-particle detector. Results of measurements with an anti-personnel landmine imitator are presented. PMID:15145438

  11. Demonstration of a solid deuterium source of ultra-cold neutrons

    E-print Network

    A. Saunders; J. M. Anaya; T. J. Bowles; B. W. Filippone; P. Geltenbort; R. E. Hill; M. Hino; S. Hoedl; G. E. Hogan; T. M. Ito; K. W. Jones; T. Kawai; K. Kirch; S. K. Lamoreaux; C. -Y. Liu; M. Makela; L. J. Marek; J. W. Martin; C. L. Morris; R. N. Mortensen; A. Pichlmaier; S. J. Seestrom; A. Serebrov; D. Smith; W. Teasdale; B. Tipton; R. B. Vogelaar; A. R. Young; J. Yuan

    2003-12-18

    Ultra-cold neutrons (UCN), neutrons with energies low enough to be confined by the Fermi potential in material bottles, are playing an increasing role in measurements of fundamental properties of the neutron. The ability to manipulate UCN with material guides and bottles, magnetic fields, and gravity can lead to experiments with lower systematic errors than have been obtained in experiments with cold neutron beams. The UCN densities provided by existing reactor sources limit these experiments. The promise of much higher densities from solid deuterium sources has led to proposed facilities coupled to both reactor and spallation neutron sources. In this paper we report on the performance of a prototype spallation neutron-driven solid deuterium source. This source produced bottled UCN densities of 145 +/-7 UCN/cm3, about three times greater than the largest bottled UCN densities previously reported. These results indicate that a production UCN source with substantially higher densities should be possible.

  12. 5 MW pulsed spallation neutron source, Preconceptual design study

    SciTech Connect

    Not Available

    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.

  13. Shielding Design of the Spallation Neutron Source (SNS)

    SciTech Connect

    Johnson, J.O.

    1998-09-17

    The shielding design is important for the construction of an intense high-energy accelerator facility like the proposed Spallation Neutron Source (SNS) due to its impact on conventional facility design, maintenance operations, and since the cost for the radiation shielding shares a considerable part of the total facility costs. A calculational strategy utilizing coupled high energy Monte Carlo calculations and multi-dimensional discrete ordinates calculations, along with semi-empirical calculations, was implemented to perform the conceptual design shielding assessment of the proposed SNS. Biological shields have been designed and assessed for the proton beam transport system and associated beam dumps, the target station, and the target service cell and general remote maintenance cell. Shielding requirements have been assessed with respect to weight, space, and dose-rate constraints for operating, shutdown, and accident conditions. A discussion of the proposed facility design, conceptual design shielding requirements, calculational strategy, source terms, preliminary results and conclusions, and recommendations for additional analyses are presented.

  14. The Spallation Neutron Source (SNS) conceptual design shielding analysis

    SciTech Connect

    Johnson, J.O.; Odano, N.; Lillie, R.A.

    1998-03-01

    The shielding design is important for the construction of an intense high-energy accelerator facility like the proposed Spallation Neutron Source (SNS) due to its impact on conventional facility design, maintenance operations, and since the cost for the radiation shielding shares a considerable part of the total facility costs. A calculational strategy utilizing coupled high energy Monte Carlo calculations and multi-dimensional discrete ordinates calculations, along with semi-empirical calculations, was implemented to perform the conceptual design shielding assessment of the proposed SNS. Biological shields have been designed and assessed for the proton beam transport system and associated beam dumps, the target station, and the target service cell and general remote maintenance cell. Shielding requirements have been assessed with respect to weight, space, and dose-rate constraints for operating, shutdown, and accident conditions. A discussion of the proposed facility design, conceptual design shielding requirements calculational strategy, source terms, preliminary results and conclusions, and recommendations for additional analyses are presented.

  15. Energy variable deuteron linac for materials research neutron source

    SciTech Connect

    Jameson, R.A.

    1990-01-01

    Basic research in new materials and materials technology is a key national resource, and several countries are making plans for advanced capabilities, including intense neutron sources. Advances in high-intensity linear accelerator technology can provide efficient drivers for such sources. Aspects such as energy variability, uniformity of target dose distribution, target bombardment from multiple directions, time-scheduled dose patterns, and other features can be provided, opening new opportunities in the experimental program. These considerations are discussed in the context of 20--40 mA continuous-current, 35-MeV compact deuteron linac facility, as a subset of designs with much larger (250 mA) current capability. The possibility for a current-upgradeable facility is briefly described. 11 refs., 2 figs., 1 tab.

  16. Spallation Neutron Source Accident Terms for Environmental Impact Statement Input

    SciTech Connect

    Devore, J.R.; Harrington, R.M.

    1998-08-01

    This report is about accidents with the potential to release radioactive materials into the environment surrounding the Spallation Neutron Source (SNS). As shown in Chap. 2, the inventories of radioactivity at the SNS are dominated by the target facility. Source terms for a wide range of target facility accidents, from anticipated events to worst-case beyond-design-basis events, are provided in Chaps. 3 and 4. The most important criterion applied to these accident source terms is that they should not underestimate potential release. Therefore, conservative methodology was employed for the release estimates. Although the source terms are very conservative, excessive conservatism has been avoided by basing the releases on physical principles. Since it is envisioned that the SNS facility may eventually (after about 10 years) be expanded and modified to support a 4-MW proton beam operational capability, the source terms estimated in this report are applicable to a 4-MW operating proton beam power unless otherwise specified. This is bounding with regard to the 1-MW facility that will be built and operated initially. See further discussion below in Sect. 1.2.

  17. The flow mechanism in the Chalk based on radio-isotope analyses of groundwater in the London Basin

    USGS Publications Warehouse

    Downing, R.A.; Pearson, F.J.; Smith, D.B.

    1979-01-01

    14C analyses of groundwaters from the Chalk of the London Basin are re-interpreted and the age of the groundwater is revised. Radio-isotope analyses are used to examine the flow mechanism in the aquifer. The evidence supports the view that a network of micro-fissures and larger intergranular pores in the matrix provides a significant part of the water pumped from Chalk wells and the major fissures distribute the water to the wells. Most of the matrix is fine-grained and contains a very old water. This diffuses into the micro-fissures and larger pores and is carried to the wells by the major fissures. ?? 1979.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. NEUTRON ACTIVATION ANALYSIS APPLICATIONS AT THE SAVANNAH RIVER SITE USING AN ISOTOPIC NEUTRON SOURCE

    SciTech Connect

    Diprete, D; C Diprete, C; Raymond Sigg, R

    2006-08-14

    NAA using {sup 252}Cf is used to address important areas of applied interest at SRS. Sensitivity needs for many of the applications are not severe; analyses are accomplished using a 21 mg {sup 252}Cf NAA facility. Because NAA allows analysis of bulk samples, it offers strong advantages for samples in difficult-to-digest matrices when its sensitivity is sufficient. Following radiochemical separation with stable carrier addition, chemical yields for a number methods are determined by neutron activation of the stable carrier. In some of the cases where no suitable stable carriers exist, the source has been used to generate radioactive tracers to yield separations.

  20. Intercalibration of physical neutron dosimetry for the RA-3 and MURR thermal neutron sources for BNCT small-animal research.

    PubMed

    Pozzi, Emiliano C C; Thorp, Silvia; Brockman, John; Miller, Marcelo; Nigg, David W; Hawthorne, M Frederick

    2011-12-01

    New thermal neutron irradiation facilities to perform cell and small-animal irradiations for Boron Neutron Capture Therapy research have been installed at the Missouri University Research Reactor and at the RA-3 research reactor facility in Buenos Aires, Argentina. Recognizing the importance of accurate and reproducible physical beam dosimetry as an essential tool for combination and intercomparisons of preclinical and clinical results from the different facilities, we have conducted an experimental intercalibration of the neutronic performance of the RA-3 and MURR thermal neutron sources. PMID:21330143

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Optimisation of the neutron source based on gas dynamic trap for transmutation of radioactive wastes

    NASA Astrophysics Data System (ADS)

    Anikeev, Andrey V.

    2012-06-01

    The Budker Institute of Nuclear Physics in collaboration with the Russian and foreign organizations develop the project of 14 MeV neutron source, which can be used for fusion material studies and for other application. The projected neutron source of plasma type is based on the plasma Gas Dynamic Trap (GDT), which is a special magnetic mirror system for plasma confinement. Presented work continues the subject of development the GDT-based neutron source (GDT-NS) for hybrid fusion-fission reactors. The paper presents the results of recent numerical optimization of such neutron source for transmutation of the long-lives radioactive wastes in spent nuclear fuel.

  3. Neutron generators with size scalability, ease of fabrication and multiple ion source functionalities

    DOEpatents

    Elizondo-Decanini, Juan M

    2014-11-18

    A neutron generator is provided with a flat, rectilinear geometry and surface mounted metallizations. This construction provides scalability and ease of fabrication, and permits multiple ion source functionalities.

  4. H- radio frequency source development at the Spallation Neutron Sourcea)

    NASA Astrophysics Data System (ADS)

    Welton, R. F.; Dudnikov, V. G.; Gawne, K. R.; Han, B. X.; Murray, S. N.; Pennisi, T. R.; Roseberry, R. T.; Santana, M.; Stockli, M. P.; Turvey, M. W.

    2012-02-01

    The Spallation Neutron Source (SNS) now routinely operates nearly 1 MW of beam power on target with a highly persistent ˜38 mA peak current in the linac and an availability of ˜90%. H- beam pulses (˜1 ms, 60 Hz) are produced by a Cs-enhanced, multicusp ion source closely coupled with an electrostatic low energy beam transport (LEBT), which focuses the 65 kV beam into a radio frequency quadrupole accelerator. The source plasma is generated by RF excitation (2 MHz, ˜60 kW) of a copper antenna that has been encased with a thickness of ˜0.7 mm of porcelain enamel and immersed into the plasma chamber. The ion source and LEBT normally have a combined availability of ˜99%. Recent increases in duty-factor and RF power have made antenna failures a leading cause of downtime. This report first identifies the physical mechanism of antenna failure from a statistical inspection of ˜75 antennas which ran at the SNS, scanning electron microscopy studies of antenna surface, and cross sectional cuts and analysis of calorimetric heating measurements. Failure mitigation efforts are then described which include modifying the antenna geometry and our acceptance/installation criteria. Progress and status of the development of the SNS external antenna source, a long-term solution to the internal antenna problem, are then discussed. Currently, this source is capable of delivering comparable beam currents to the baseline source to the SNS and, an earlier version, has briefly demonstrated unanalyzed currents up to ˜100 mA (1 ms, 60 Hz) on the test stand. In particular, this paper discusses plasma ignition (dc and RF plasma guns), antenna reliability, magnet overheating, and insufficient beam persistence.

  5. On replacing Am-Be neutron sources in compensated porosity logging tools.

    PubMed

    Peeples, Cody R; Mickael, Medhat; Gardner, Robin P

    2010-01-01

    Authors explored the direct replacement of Am-Be neutron sources in neutron porosity logging tools through Monte Carlo simulations using MCNP5. (252)Cf and electronic accelerator neutron sources based on the Deuterium-Tritium fusion reaction were considered. Between the sources, a tradeoff was noted between sensitivity to the presence of hydrogen and uncertainty due to counting statistics. It was concluded that both replacement sources as well as accelerator sources based on the Deuterium-Deuterium fusion reaction warrant further consideration as porosity log sources. PMID:20047837

  6. Materials compatibility studies for the Spallation Neutron Source

    SciTech Connect

    DiStefano, J.R.; Pawel, S.J.; Manneschmidt, E.T.

    1998-11-01

    The Spallation Neutron Source (SNS) is a high power facility for producing neutrons that utilizes flowing liquid mercury inside an austenitic stainless steel container as the target for a 1.0 GeV proton beam. Type 316 SS has been selected as the container material for the mercury and consequences of exposure of 316 SS to radiation, thermal shock, thermal stress, cavitation and hot, flowing mercury are all being addressed by R and D programs. In addition, corrosion studies also include evaluation of Inconel 718 because it has been successfully used in previous spallation neutron systems as a window material. Two types of compatibility issues relative to 316 SS/mercury and Inconel 718/mercury are being examined: (1) liquid metal embrittlement (LME) and (2) temperature gradient mass transfer. Studies have shown that mercury does not easily wet type 316 SS below 275 C. In the LME experiments, attempts were made to promote wetting of the steel by mercury either by adding gallium to the mercury or coating the specimen with a tin-silver solder that the mercury easily wets. The latter proved more reliable in establishing wetting, but there was no evidence of LME in any of the constant extension rate tensile tests either at 23 or 100 C. Inconel 718 also showed no change in room temperature properties when tested in mercury or mercury-gallium. However, there was evidence that the fracture was less ductile. Preliminary evaluation of mass transfer of either type 316 SS or Inconel 718 in mercury or mercury-gallium at 350 C (maximum temperature) did not reveal significant effects. Two 5,000 h thermal convection loop tests of type 316 SS are in progress, with specimens in both hot and cold test regions, at 300 and 240 C, respectively.

  7. On accelerator-based neutron sources and neutron field characterization with low energy neutron spectrometer based on position sensitive 3He counter.

    PubMed

    Murata, I; Miyamaru, H; Kato, I; Mori, Y

    2009-07-01

    The development of new neutron sources for BNCT applications, based on particle accelerators is currently underway all over the world. Though nuclear reactors were used for a long time as the only neutron source available having the requested flux levels, the accelerator-based ones have recently been investigated on the other hand due to its easy-to-use and acceptable performances. However, when using an accelerator, various secondary particles would be emitted which forms a troublesome background. Moreover, the neutrons produced have usually an energy spectrum somewhat different from the requested one and thus should be largely moderated. An additional issue to be taken into account is the patient positioning, which should be close to the neutron source, in order to take advantage of a neutron flux level high enough to limit the BNCT treatment time within 1h. This implies that, inside a relatively narrow space, neutrons should be moderated, while unnecessary secondary particles should be shielded. Considering that a background-free neutron field from an accelerator-driven neutron source dedicated to BNCT application is generally difficult to be provided, the characterization of such a neutron field will have to be clearly assessed. In the present study, a low energy neutron spectrometer has been thus designed and is now being developed to measure the accelerator-based neutron source performance. The presently proposed spectrometer is based on a (3)He proportional counter, which is 50 cm long and 5 cm in diameter, with a gas pressure of 0.5 MPa. It is quite unique that the spectrometer is set up in parallel with the incident neutron beam and a reaction depth distribution is measured by it as a position sensitive detector. Recently, a prototype detector has been developed and the signal test is now underway. In this paper, the feature of the accelerator-based neutron sources is outlined and importance of neutron field characterization is discussed. And the developed new low energy neutron spectrometer for the characterization is detailed. PMID:19376716

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

    SciTech Connect

    Campbell, J.H.; King-Jones, K.H.; Selby, D.L.; Harrington, R.M.; Thompson, P.B.

    1995-01-01

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

  9. Quantifying time in sedimentary successions by radio-isotopic dating of ash beds

    NASA Astrophysics Data System (ADS)

    Schaltegger, Urs

    2014-05-01

    Sedimentary rock sequences are an accurate record of geological, chemical and biological processes throughout the history of our planet. If we want to know more about the duration or the rates of some of these processes, we can apply methods of absolute age determination, i.e. of radio-isotopic dating. Data of highest precision and accuracy, and therefore of highest degree of confidence, are obtained by chemical abrasion, isotope-dilution, thermal ionization mass spectrometry (CA-ID-TIMS) 238U-206Pb dating techniques, applied to magmatic zircon from ash beds that are interbedded with the sediments. This techniques allows high-precision estimates of age at the 0.1% uncertainty for single analyses, and down to 0.03% uncertainty for groups of statistically equivalent 206Pb/238U dates. Such high precision is needed, since we would like the precision to be approximately equivalent or better than the (interpolated) duration of ammonoid zones in the Mesozoic (e.g., Ovtcharova et al. 2006), or to match short feedback rates of biological, climatic, or geochemical cycles after giant volcanic eruptions in large igneous provinces (LIP's), e.g., at the Permian/Triassic or the Triassic/Jurassic boundaries. We also wish to establish as precisely as possible temporal coincidence between the sedimentary record and short-lived volcanic events within the LIP's. Precision and accuracy of the U-Pb data has to be traceable and quantifiable in absolute terms, achieved by direct reference to the international kilogram, via an absolute calibration of the standard and isotopic tracer solutions. Only with a perfect control on precision and accuracy of radio-isotopic data, we can confidently determine whether two ages of geological events are really different, and avoid mistaking interlaboratory or interchronometer biases for age difference. The development of unprecedented precision of CA-ID-TIMS 238U-206Pb dates led to the recognition of protracted growth of zircon in a magmatic liquid (see, e.g., Schoene et al. 2012), which then becomes transferred into volcanic ashes as excess dispersion of 238U-206Pb dates (see, e.g., Guex et al. 2012). Zircon is crystallizing in the magmatic liquid shortly before the volcanic eruption; we therefore aim at finding the youngest zircon date or youngest statistically equivalent cluster of 238U-206Pb dates as an approximation of ash deposition (Wotzlaw et al. 2013). Time gaps between last zircon crystallization and eruption ("?t") may be as large as 100-200 ka, at the limits of analytical precision. Understanding the magmatic crystallization history of zircon is the fundamental background for interpreting ash bed dates in a sedimentary succession. Ash beds of different stratigraphic position and age my be generated within different magmatic systems, showing different crystallization histories. A sufficient number of samples (N) is therefore of paramount importance, not to lose the stratigraphic age control in a given section, and to be able to discard samples with large ?t - but, how large has to be "N"? In order to use the youngest zircon or zircons as an approximation of the age of eruption and ash deposition, we need to be sure that we have quantitatively solved the problem of post-crystallization lead loss - but, how can we be sure?! Ash bed zircons are prone to partial loss of radiogenic lead, because the ashes have been flushed by volcanic gases, as well as brines during sediment compaction. We therefore need to analyze a sufficient number of zircons (n) to be sure not to miss the youngest - but, how large has to be "n"? Analysis of trace elements or oxygen, hafnium isotopic compositions in dated zircon may sometimes help to distinguish zircon that is in equilibrium with the last magmatic liquid, from those that are recycled from earlier crystallization episodes, or to recognize zircon with partial lead loss (Schoene et al. 2010). Respecting these constraints, we may arrive at accurate correlation of periods of global environmental and biotic disturbance (from ash bed analysis

  10. Materials for spallation neutron sources, with emphasis on SNS facility

    SciTech Connect

    Mansur, L.K.

    1999-09-01

    The materials requirements in a high-power spallation neutron source like the SNS are particularly demanding. Materials at the target station are of special concern; these include the containment vessel and protective shroud for the mercury target material, beam windows, support structures, moderator housings, and beam tubes. The material chosen for the mercury containment vessel is Type 316 stainless steel (316SS). This choice is based on the extensive background of experience with 316SS and on its good fabricability and availability. While much has been learned about the effect of radiation on the properties of 316SS, the preponderance of this information stems from fission reactor irradiations, where the average neutron energy is only 1 to 2 MeV and relatively few neutrons are present with energies above {approximately}10 MeV. By contrast, the energies of the spallation neutrons at the SNS extend up to the 1000-MeV energy of the incident protons. However, because of the design of the target module, irradiation creep is not expected to be a significant problem. The major concern is for radiation embrittlement. Mercury is known to be an aggressive medium, and corrosion and compatibility studies for 316SS and INCONEL 718 are included in the research and development program on SNS materials. INCONEL 718 is under consideration as a beam window material. Two issues are receiving particular attention: liquid-metal embrittlement and temperature gradient mass transfer. Constant-strain-rate tensile tests were conducted in mercury and mercury-gallium at 23 C for 316SS and INCONEL 718 and at 100 C for 316SS; in all the tests there was no evidence of liquid metal embrittlement. In addition, preliminary mass transfer tests on 3165SS or INCONEL 718 at temperatures up to 350 C reveled no significant effects. Fatigue tests in mercury have recently been initiated. As a partial simulation of SNS conditions, they provide a more severe probe for possible ductility loss associated with a liquid-metal environment.

  11. Spallation neutron source cryomodule heat loads and thermal design

    SciTech Connect

    E. F. Daly; V. Ganni; C. H. Rode; W. J. Schneider; K. M. Wilson; M. A. Wiseman

    2002-05-10

    When complete, the Spallation Neutron Source (SNS) will provide a 1 GeV, 2 MW beam for experiments. One portion of the machine's linac consists of over 80 Superconducting Radio Frequency (SRF) 805 MHz cavities housed in a minimum of 23 cryomodules operating at a saturation temperature of 2.1 K. Minimization of the total heat load is critical to machine performance and for efficient operation of the system. The total heat load of the cryomodules consists of the fixed static load and the dynamic load, which is proportional to the cavity performance. The helium refrigerator supports mainly the cryomodule loads and to a lesser extent the distribution system loads. The estimated heat loads and calculated thermal performance are discussed along with two unique features of this design: the helium heat exchanger housed in the cryomodule return end can and the helium gas cooled fundamental power coupler.

  12. Electron Cloud Mitigation in the Spallation Neutron Source Ring

    SciTech Connect

    Wei, J.; Blaskiewicz, Michael; Brodowski, J.; Cameron, P.; Davino, Daniele; Fedotov, A.; He, P.; Hseuh, H.; Lee, Y.Y.; Ludewig, H.; Meng, W.; Raparia, D.; Tuozzolo, J.; Zhang, S.Y.; Catalan-Lasheras, N.; Macek, R.J.; Furman, Miguel A.; Aleksandrov, A.; Cousineau, S.; Danilov, V.; Henderson, S.; /Brookhaven /CERN /LANL, Ctr. for Nonlinear Studies /LBL, Berkeley /Oak Ridge /SLAC

    2008-03-17

    The Spallation Neutron Source (SNS) accumulator ring is designed to accumulate, via H{sup -} injection, protons of 2 MW beam power at 1 GeV kinetic energy at a repetition rate of 60 Hz [1]. At such beam intensity, electron-cloud is expected to be one of the intensity-limiting mechanisms that complicate ring operations. This paper summarizes mitigation strategy adopted in the design, both in suppressing electron-cloud formation and in enhancing Landau damping, including tapered magnetic field and monitoring system for the collection of stripped electrons at injection, TiN coated beam chamber for suppression of the secondary yield, clearing electrodes dedicated for the injection region and parasitic on BPMs around the ring, solenoid windings in the collimation region, and planning of vacuum systems for beam scrubbing upon operation.

  13. Electron-cloud mitigation in the spallation neutron source ring

    SciTech Connect

    Wei, J.; Blaskiewicz, M.; Brodowski, J.; Cameron, P.; Davino, D.; Fedotov, A.; He, P.; Hseuh, H.; Lee, Y.Y.; Meng, W.; Raparia, D.; Tuozzolo, J.; Zhang, S.Y.; Danilov, V.; Henderson, S.; Furman, M.; Pivi, M.; Macek, R.

    2003-05-01

    The Spallation Neutron Source (SNS) accumulator ring is designed to accumulate, via H- injection, protons of 2 MW beam power at 1 GeV kinetic energy at a repetition rate of 60 Hz [1]. At such beam intensity, electron cloud is expected to be one of the intensity-limiting mechanisms that complicate ring operations. This paper summarizes mitigation strategy adopted in the design, both in suppressing electron-cloud formation and in enhancing Landau damping, including tapered magnetic field and monitoring system for the collection of stripped electrons at injection, TiN coated beam chamber for suppression of the secondary yield, clearing electrodes dedicated for the injection region and parasitic on BPMs around the ring, solenoid windings in the collimation region, and planning of vacuum systems for beam scrubbing upon operation.

  14. CONSTRUCTION STATUS AND ISSUES OF THE SPALLATION NEUTRON SOURCE RING.

    SciTech Connect

    WEI,J.

    2004-07-05

    The Spallation Neutron Source (SNS) ring is designed to accumulate beam pulses of 1.5 x 10{sup 14} protons of 1 GeV kinetic energy at a repetition rate of 60 Hz [1]. At such beam intensity and power, key design challenges include control of beam loss and radio-activation, construction of high-quality large-aperture magnets and power supplies, design of robust injection and extraction systems, minimization of beam-coupling impedances, and mitigation of electron-cloud effects. This paper discusses the status of the ring systems with emphasis on technical challenges and issues, and presents future perspectives towards a next-generation high-intensity facility.

  15. Probing neutrino magnetic moments at Spallation Neutron Source facilities

    E-print Network

    T. S. Kosmas; O. G. Miranda; D. K. Papoulias; M. Tortola; J. W. F. Valle

    2015-07-15

    Majorana neutrino electromagnetic properties are studied through neutral current coherent neutrino-nucleus scattering. We focus on the potential of the recently planned COHERENT experiment at the Spallation Neutron Source to probe muon-neutrino magnetic moments. The resulting sensitivities are determined on the basis of a chi^2 analysis employing realistic nuclear structure calculations in the context of the quasi-particle random phase approximation. We find that they can improve existing limits by half an order of magnitude. In addition, we show that these facilities allow for Standard Model precision tests in the low energy regime, with a competitive determination of the weak mixing angle. Finally, they also offer the capability to probe other electromagnetic neutrino properties, such as the neutrino charge-radius. We illustrate our results for various choices of experimental setup and target material.

  16. Probing neutrino magnetic moments at Spallation Neutron Source facilities

    E-print Network

    Kosmas, T S; Papoulias, D K; Tortola, M; Valle, J W F

    2015-01-01

    Majorana neutrino electromagnetic properties are studied through neutral current coherent neutrino-nucleus scattering. We focus on the potential of the recently planned COHERENT experiment at the Spallation Neutron Source to probe muon-neutrino magnetic moments. The resulting sensitivities are determined on the basis of a $\\chi^2$ analysis employing realistic nuclear structure calculations in the context of the quasi-particle random phase approximation (QRPA). We find that they can improve existing limits by half an order of magnitude. In addition, we show that these facilities allow for Standard Model precision tests in the low energy regime, with a competitive determination of the weak mixing angle. Finally, they also offer the capability to probe other electromagnetic neutrino properties, such as the neutrino charge-radius. We illustrate our results for various choices of experimental setup and target material.

  17. Probing neutrino magnetic moments at the Spallation Neutron Source facility

    NASA Astrophysics Data System (ADS)

    Kosmas, T. S.; Miranda, O. G.; Papoulias, D. K.; Tórtola, M.; Valle, J. W. F.

    2015-07-01

    Majorana neutrino electromagnetic properties are studied through neutral current coherent neutrino-nucleus scattering. We focus on the potential of the recently planned COHERENT experiment at the Spallation Neutron Source to probe muon-neutrino magnetic moments. The resulting sensitivities are determined on the basis of a ?2 analysis employing realistic nuclear structure calculations in the context of the quasiparticle random phase approximation. We find that they can improve existing limits by half an order of magnitude. In addition, we show that these facilities allow for standard model precision tests in the low energy regime, with a competitive determination of the weak mixing angle. Finally, they also offer the capability to probe other electromagnetic neutrino properties, such as the neutrino charge radius. We illustrate our results for various choices of experimental setup and target material.

  18. Coded moderator approach for fast neutron source detection and localization at standoff

    NASA Astrophysics Data System (ADS)

    Littell, Jennifer; Lukosi, Eric; Hayward, Jason; Milburn, Robert; Rowan, Allen

    2015-06-01

    Considering the need for directional sensing at standoff for some security applications and scenarios where a neutron source may be shielded by high Z material that nearly eliminates the source gamma flux, this work focuses on investigating the feasibility of using thermal neutron sensitive boron straw detectors for fast neutron source detection and localization. We utilized MCNPX simulations to demonstrate that, through surrounding the boron straw detectors by a HDPE coded moderator, a source-detector orientation-specific response enables potential 1D source localization in a high neutron detection efficiency design. An initial test algorithm has been developed in order to confirm the viability of this detector system's localization capabilities which resulted in identification of a 1 MeV neutron source with a strength equivalent to 8 kg WGPu at 50 m standoff within ±11°.

  19. Determining 252Cf source strength by absolute passive neutron correlation counting

    NASA Astrophysics Data System (ADS)

    Croft, S.; Henzlova, D.

    2013-06-01

    Physically small, lightly encapsulated, radionuclide sources containing 252Cf are widely used for a vast variety of industrial, medical, educational and research applications requiring a convenient source of neutrons. For many quantitative applications, such as detector efficiency calibrations, the absolute strength of the neutron emission is needed. In this work we show how, by using a neutron multiplicity counter the neutron emission rate can be obtained with high accuracy. This provides an independent and alternative way to create reference sources in-house for laboratories such as ours engaged in international safeguards metrology. The method makes use of the unique and well known properties of the 252Cf spontaneous fission system and applies advanced neutron correlation counting methods. We lay out the foundation of the method and demonstrate it experimentally. We show that accuracy comparable to the best methods currently used by national bodies to certify neutron source strengths is possible.

  20. The Advanced Neutron Source (ANS) project: A world-class research reactor facility

    SciTech Connect

    Thompson, P.B.; Meek, W.E.

    1993-07-01

    This paper provides an overview of the Advanced Neutron Source (ANS), a new research facility being designed at Oak Ridge National Laboratory. The facility is based on a 330 MW, heavy-water cooled and reflected reactor as the neutron source, with a thermal neutron flux of about 7.5{times}10{sup 19}m{sup {minus}2}{center_dot}sec{sup {minus}1}. Within the reflector region will be one hot source which will serve 2 hot neutron beam tubes, two cryogenic cold sources serving fourteen cold neutron beam tubes, two very cold beam tubes, and seven thermal neutron beam tubes. In addition there will be ten positions for materials irradiation experiments, five of them instrumented. The paper touches on the project status, safety concerns, cost estimates and scheduling, a description of the site, the reactor, and the arrangements of the facilities.

  1. The COHERENT Experiment at the Spallation Neutron Source

    E-print Network

    COHERENT Collaboration; D. Akimov; P. An; C. Awe; P. S. Barbeau; P. Barton; B. Becker; V. Below; A. Bolozdynya; A. Burenkov; B. Cabrera-Palmer; J. I. Collar; R. J. Cooper; R. L. Cooper; C. Cuesta; D. Dean; J. Detwiler; Y. Efremenko; S. R. Elliott; N. Fields; W. Fox; A. Galindo-Uribarri; M. Green; M. Heath; S. Hedges; N. Herman; D. Hornback; E. B. Iverson; L. Kaufman; S. R. Klein; A. Khromov; A. Konovalev; A. Kumpan; C. Leadbetter; L. Li; W. Lu; A. Melikyan; D. Markoff; K. Miller; M. Middlebrook; P. Mueller; P. Naumov; J. Newby; D. Parno; S. Penttila; G. Perumpilly; D. Radford; H. Ray; J. Raybern; D. Reyna; G. C. Rich; D. Rimal; D. Rudik; K. Scholberg; B. Scholz; W. M. Snow; A. Sosnovchev; A. Shakirov; S. Suchyta; B. Suh; R. Tayloe; R. T. Thornton; A. Tolstukhin; K. Vetter; C. H. Yu

    2015-09-29

    The COHERENT collaboration's primary objective is to measure coherent elastic neutrino-nucleus scattering (CEvNS) using the unique, high-quality source of tens-of-MeV neutrinos provided by the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). In spite of its large cross section, the CEvNS process has never been observed, due to tiny energies of the resulting nuclear recoils which are out of reach for standard neutrino detectors. The measurement of CEvNS has now become feasible, thanks to the development of ultra-sensitive technology for rare decay and weakly-interacting massive particle (dark matter) searches. The CEvNS cross section is cleanly predicted in the standard model; hence its measurement provides a standard model test. It is relevant for supernova physics and supernova-neutrino detection, and enables validation of dark-matter detector background and detector-response models. In the long term, precision measurement of CEvNS will address questions of nuclear structure. COHERENT will deploy multiple detector technologies in a phased approach: a 14-kg CsI[Na] scintillating crystal, 15 kg of p-type point-contact germanium detectors, and 100 kg of liquid xenon in a two-phase time projection chamber. Following an extensive background measurement campaign, a location in the SNS basement has proven to be neutron-quiet and suitable for deployment of the COHERENT detector suite. The simultaneous deployment of the three COHERENT detector subsystems will test the $N^2$ dependence of the cross section and ensure an unambiguous discovery of CEvNS. This document describes concisely the COHERENT physics motivations, sensitivity and plans for measurements at the SNS to be accomplished on a four-year timescale.

  2. The COHERENT Experiment at the Spallation Neutron Source

    SciTech Connect

    Elliott, Steven Ray

    2015-09-30

    The COHERENT collaboration's primary objective is to measure coherent elastic neutrino- nucleus scattering (CEvNS) using the unique, high-quality source of tens-of-MeV neutrinos provided by the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). In spite of its large cross section, the CEvNS process has never been observed, due to tiny energies of the resulting nuclear recoils which are out of reach for standard neutrino detectors. The measurement of CEvNS has now become feasible, thanks to the development of ultra-sensitive technology for rare decay and weakly-interacting massive particle (dark matter) searches. The CEvNS cross section is cleanly predicted in the standard model; hence its measurement provides a standard model test. It is relevant for supernova physics and supernova-neutrino detection, and enables validation of dark-matter detector background and detector-response models. In the long term, precision measurement of CEvNS will address questions of nuclear structure. COHERENT will deploy multiple detector technologies in a phased approach: a 14-kg CsI[Na] scintillating crystal, 15 kg of p-type point-contact germanium detectors, and 100 kg of liquid xenon in a two-phase time projection chamber. Following an extensive background measurement campaign, a location in the SNS basement has proven to be neutron-quiet and suitable for deployment of the COHERENT detector suite. The simultaneous deployment of the three COHERENT detector subsystems will test the N=2 dependence of the cross section and ensure an unambiguous discovery of CEvNS. This document describes concisely the COHERENT physics motivations, sensitivity and plans for measurements at the SNS to be accomplished on a four-year timescale.

  3. Critical beam dynamical issues in neutron spallation sources

    NASA Astrophysics Data System (ADS)

    Pabst, M.; Bongardt, K.; Letchford, A. P.

    1996-06-01

    The accelerator part of proposed neutron spallation sources consists of a high intensity linac and compressor ring or rapid cycling synchrotron. The most critical part of such a high current machine is to keep activation caused by particle loss along the linac or at ring injection down to an acceptable limit. Sources of particle loss along the linac can be beam mismatch, resonances of any kind, temperature transfer within a bunch and/or nonlinear internal or external forces. In addition machine errors like misalignments, tolerances, and rf errors have to be considered. All these sources cause emittance growth. The common way of setting up the beam dynamics of high intensity linacs is governed by avoiding these sources and testing it by Monte-Carlo simulations. To get information on the possible loss mechanism, the only way is to increase the particle number of the Monte-Carlo simulations and to study phase space distributions in detail. Monte-Carlo simulations with 50000 particles for the 1.334 GeV coupled cavity linac of the European Spallation Source (ESS) are presented. It is shown that it is possible to design a non-space charge dominated linac for 200 mA bunch current with almost constant emittances. A detailed study of the phase space distribution along the linac shows a small number of halo particles nearby the bunch core. This halo is acceptable for ring injection. Some information related to particle loss in the linac and in the compressor ring afterwards is extracted and comments for positioning scrapers are made.

  4. A source of ultra-cold neutrons for the gravitational spectrometer GRANIT

    E-print Network

    Schmidt-Wellenburg, P; Nesvizhevsky, V V; Plonka, C; Soldner, T; Vezzu, F; Zimmer, O

    2007-01-01

    We present the status of the development of a dedicated high density ultra-cold neutron (UCN) source dedicated to the gravitational spectrometer GRANIT. The source employs superthermal conversion of cold neutrons to UCN in superfluid helium. Tests have shown that UCN produced inside the liquid can be extracted into vacuum. Furthermore a dedicated neutron selection channel was tested to maintain high initial density and extract only neutrons with a vertical velocity component 20 cm/s for the spectrometer. This new source would have a phase-space density of 0.18 cm-3(m/s)-3 for the spectrometer.

  5. A source of ultra-cold neutrons for the gravitational spectrometer GRANIT

    E-print Network

    P. Schmidt-Wellenburg; P. Geltenbort; V. V. Nesvizhevsky; C. Plonka; T. Soldner; F. Vezzu; O. Zimmer

    2007-08-21

    We present the status of the development of a dedicated high density ultra-cold neutron (UCN) source dedicated to the gravitational spectrometer GRANIT. The source employs superthermal conversion of cold neutrons to UCN in superfluid helium. Tests have shown that UCN produced inside the liquid can be extracted into vacuum. Furthermore a dedicated neutron selection channel was tested to maintain high initial density and extract only neutrons with a vertical velocity component 20 cm/s for the spectrometer. This new source would have a phase-space density of 0.18 cm-3(m/s)-3 for the spectrometer.

  6. Conceptual design of a high-intensity positron source for the Advanced Neutron Source

    SciTech Connect

    Hulett, L.D.; Eberle, C.C.

    1994-12-01

    The Advanced Neutron Source (ANS) is a planned new basic and applied research facility based on a powerful steady-state research reactor that provides neutrons for measurements and experiments in the fields of materials science and engineering, biology, chemistry, materials analysis, and nuclear science. The useful neutron flux will be at least five times more than is available in the world`s best existing reactor facility. Construction of the ANS provides a unique opportunity to build a positron spectroscopy facility (PSF) with very-high-intensity beams based on the radioactive decay of a positron-generating isotope. The estimated maximum beam current is 1000 to 5000 times higher than that available at the world`s best existing positron research facility. Such an improvement in beam capability, coupled with complementary detectors, will reduce experiment durations from months to less than one hour while simultaneously improving output resolution. This facility will remove the existing barriers to the routine use of positron-based analytical techniques and will be a giant step toward realization of the full potential of the application of positron spectroscopy to materials science. The ANS PSF is based on a batch cycle process using {sup 64}Cu isotope as the positron emitter and represents the status of the design at the end of last year. Recent work not included in this report, has led to a proposal for placing the laboratory space for the positron experiments outside the ANS containment; however, the design of the positron source is not changed by that relocation. Hydraulic and pneumatic flight tubes transport the source material between the reactor and the positron source where the beam is generated and conditioned. The beam is then transported through a beam pipe to one of several available detectors. The design presented here includes all systems necessary to support the positron source, but the beam pipe and detectors have not been addressed yet.

  7. Phantom studies of Cd, Hg and Cl by prompt gamma neutron activation analysis using a 238Pu Be neutron source

    NASA Astrophysics Data System (ADS)

    Grinyer, J.; Atanackovic, J.; Byun, S. H.; Chettle, D. R.

    2007-10-01

    Prompt gamma neutron activation analysis is a means of non-invasive monitoring for occupational exposure to toxic heavy metals such as Cd and Hg. Preliminary kidney detection limits from previous phantom studies at McMaster were 13.6 ± 0.2 ppm for Cd (125 mL phantom) and 315 ± 24 ppm for Hg (125 mL phantom) using the 238Pu-Be neutron source and 0.88 ± 0.01 ppm for Cd (125 mL phantom) and 16.91 ± 0.05 ppm for Hg (30 mL phantom) using the thermal neutron beam port at the McMaster Nuclear Reactor. The detection limits vary greatly between the two methods due to differences in experimental set-up, neutron energy spectra and a difference in dose by more than a factor of 100. The Hg detection limit from preliminary data is much higher than expected for both neutron source types. In order to explain the apparent detection limit discrepancy, measurements of Hg and Cd phantoms were performed using the 238Pu-Be neutron source. The results were compared to phantom measurements of Cl, a well-known neutron activation element.

  8. Accelerator based neutron source for neutron capture therapy B. Bayanov, Yu. Belchenko, V. Belov, V. Davydenko, A. Donin, A. Dranichnikov, A. Ivanov,

    E-print Network

    Taskaev, Sergey Yur'evich

    capture and fast neutron therapy for hospital. Innovative approach is based upon vacuum insulation tandem, Russia. In the present report, the pilot facility design is presented and discussed. Design features neutron source for neutron capture and fast neutron therapy for hospital (Bayanov, 1998). Innovative

  9. Overview of the national spallation neutron source with emphasis on the target station

    SciTech Connect

    Gabriel, T.A.; Barnes, J.N.; Charlton, L.A.

    1997-06-01

    The technologies that are being utilized to design and build a state-of-the-art neutron spallation source, the National Spallation Neutron Source (NSNS), are discussed. Emphasis is given to the technology issues that present the greatest scientific challenges. The present facility configuration, ongoing analysis and the planned hardware research and development program are also described.

  10. Initial tests of the Spallation Neutron Source H{sup -} ion source with an external antenna

    SciTech Connect

    Welton, R.F.; Stockli, M.P.; Murray, S.N.; Kang, Y.; Peters, J.

    2006-03-15

    The ion source for the Spallation Neutron Source (SNS) is a radio-frequency (rf) multicusp source designed to deliver H{sup -} beam pulses of 40 mA to the SNS accelerator with a normalized root-mean-square emittance of less than 0.2{pi} mm mrad, with a pulse length of 1 ms and a repetition rate of 60 Hz. In order to achieve this performance the source must operate with both high-pulse rf power, {approx}50 kW, and high average rf power, {approx}3.5 kW, over a continuous operational period of 3 weeks. During operation at these power levels the plasma-immersed, porcelain-coated rf antenna is susceptible to damage, limiting source lifetime. We are therefore developing an ion source where the plasma is separated from the Cu antenna by an Al{sub 2}O{sub 3} discharge chamber. This article describes the ion source, presents initial beam extraction measurements, and details our ongoing effort to develop this concept into a suitable ion source for the SNS.

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

    SciTech Connect

    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.

  12. Compact deuterium-tritium neutron generator using a novel field ionization source

    SciTech Connect

    Ellsworth, J. L. Falabella, S.; Sanchez, J.; Tang, V.; Wang, H.

    2014-11-21

    Active interrogation using neutrons is an effective method for detecting shielded nuclear material. A lightweight, lunch-box-sized, battery-operated neutron source would enable new concepts of operation in the field. We have developed at-scale components for a highly portable, completely self-contained, pulsed Deuterium-Tritium (DT) neutron source producing 14?MeV neutrons with average yields of 10{sup 7}?n/s. A gated, field ionization ion source using etched electrodes has been developed that produces pulsed ion currents up to 500?nA. A compact Cockcroft-Walton high voltage source is used to accelerate deuterons into a metal hydride target for neutron production. The results of full scale DT tests using the field ionization source are presented.

  13. Use of the WNR spallation neutron source at LAMPF to determine the absolute efficiency of a neutron scintillation detector

    SciTech Connect

    Staples, P.A.; Egan, J.J.; Kegel, G.H.R.; Woodring, M.L.; DeSimone, D.J.; Lisowski, P.W.

    1994-06-01

    Prompt fission neutron spectrum measurements at the University of Massachusetts Lowell 5.5 MV Van de Graaff accelerator laboratory require that the neutron detector efficiency be well known over a neutron energy range of 100 keV to 20 MeV. The efficiency of the detector, has been determined for energies greater than 5.0 MeV using the Weapons Neutron Research (WNR) white neutron source at the Los Alamos Meson Physics Facility (LAMPF) in a pulsed beam, time-of-flight (TOF) experiment. Carbon matched polyethylene and graphite scatterers were used to obtain a hydrogen spectrum. The detector efficiency was determined using the well known H(n,n) scattering cross section. Results are compared to the detector efficiency calculation program SCINFUL available from the Radiation Shielding Information Center at Oak Ridge National Laboratory.

  14. Characterization of an accelerator neutron source based on the Be(d,n) reaction

    SciTech Connect

    Meadows, J.W.; Smith, D.L.

    1992-07-01

    Small accelerator neutron sources offer considerable potential for applied neutron radiography applications. Among the desirable features are relatively low costs, limited operating hazards, opportunities for tailoring primary neutron spectra, compactness and portability, and modest licensing requirements (compared to fission reactors). However, exploitation of this potential has been somewhat limited, in part, by incomplete knowledge of the primary-neutron yields and energy spectra from the favorable source reactions. This work describes an extensive experimental determination of zero-degree neutron yields and energy spectra from the {sup 9}Be(d,n) {sup 10}B source reaction, for incident deuterons of 2.6 to 7.0 MeV on a thick beryllium metal target. This information was acquired by means of time-of-flight measurements that were conducted with a calibrated uranium fission detector. Tables and plots of neutron-producing reaction data are presented. This information provides input which will be essential for applications involving the primary spectrum as well as for the design of neutron moderators and for calculation of thermal-neutron yield factors. Such analyses will be prerequisites in assessing the suitability of this source for various possible neutron radiography applications and, also, for assisting in the design of appropriate detectors to be used in neutron imaging devices.

  15. Characterization of an accelerator neutron source based on the Be(d,n) reaction

    SciTech Connect

    Meadows, J.W.; Smith, D.L.

    1992-01-01

    Small accelerator neutron sources offer considerable potential for applied neutron radiography applications. Among the desirable features are relatively low costs, limited operating hazards, opportunities for tailoring primary neutron spectra, compactness and portability, and modest licensing requirements (compared to fission reactors). However, exploitation of this potential has been somewhat limited, in part, by incomplete knowledge of the primary-neutron yields and energy spectra from the favorable source reactions. This work describes an extensive experimental determination of zero-degree neutron yields and energy spectra from the {sup 9}Be(d,n) {sup 10}B source reaction, for incident deuterons of 2.6 to 7.0 MeV on a thick beryllium metal target. This information was acquired by means of time-of-flight measurements that were conducted with a calibrated uranium fission detector. Tables and plots of neutron-producing reaction data are presented. This information provides input which will be essential for applications involving the primary spectrum as well as for the design of neutron moderators and for calculation of thermal-neutron yield factors. Such analyses will be prerequisites in assessing the suitability of this source for various possible neutron radiography applications and, also, for assisting in the design of appropriate detectors to be used in neutron imaging devices.

  16. The COHERENT Experiment at the Spallation Neutron Source

    E-print Network

    Akimov, D; Awe, C; Barbeau, P S; Barton, P; Becker, B; Below, V; Bolozdynya, A; Burenkov, A; Cabrera-Palmer, B; Collar, J I; Cooper, R J; Cooper, R L; Cuesta, C; Dean, D; Detwiler, J; Efremenko, Y; Elliott, S R; Fields, N; Fox, W; Galindo-Uribarri, A; Green, M; Heath, M; Hedges, S; Herman, N; Hornback, D; Iverson, E B; Kaufman, L; Klein, S R; Khromov, A; Konovalev, A; Kumpan, A; Leadbetter, C; Li, L; Lu, W; Melikyan, A; Markoff, D; Miller, K; Middlebrook, M; Mueller, P; Naumov, P; Newby, J; Parno, D; Penttila, S; Perumpilly, G; Radford, D; Ray, H; Raybern, J; Reyna, D; Rich, G C; Rimal, D; Rudik, D; Scholberg, K; Scholz, B; Snow, W M; Sosnovchev, A; Shakirov, A; Suchyta, S; Suh, B; Tayloe, R; Thornton, R T; Tolstukhin, A; Vetter, K; Yu, C H

    2015-01-01

    The COHERENT collaboration's primary objective is to measure coherent elastic neutrino-nucleus scattering (CEvNS) using the unique, high-quality source of tens-of-MeV neutrinos provided by the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). In spite of its large cross section, the CEvNS process has never been observed, due to tiny energies of the resulting nuclear recoils which are out of reach for standard neutrino detectors. The measurement of CEvNS has now become feasible, thanks to the development of ultra-sensitive technology for rare decay and weakly-interacting massive particle (dark matter) searches. The CEvNS cross section is cleanly predicted in the standard model; hence its measurement provides a standard model test. It is relevant for supernova physics and supernova-neutrino detection, and enables validation of dark-matter detector background and detector-response models. In the long term, precision measurement of CEvNS will address questions of nuclear structure. COHERENT...

  17. Mechanical Engineering of the Linac for the Spallation Neutron Source

    SciTech Connect

    Bultman, N.K.; Chen, Z.; Collier, M.; Erickson, J.L.; Guthrie, A.; Hunter, W.T.; Ilg, T.; Meyer, R.K.; Snodgrass, N.L.

    1999-03-29

    The linac for the Spallation Neutron Source (SNS) Project will accelerate an average current of 1 mA of H{sup {minus}} ions from 20 MeV to 1GeV for injection into an accumulator ring. The linac will be an intense source of H{sup {minus}} ions and as such requires advanced design techniques to meet project technical goals as well as to minimize costs. The DTL, CCDTL and CCL are 466m long and operate at 805 MHz with a maximum H{sup {minus}} input current of 28 mA and 7% rf duty factor. The Drift Tube Linac is a copper-plated steel structure using permanent magnetic quadrupoles. The Coupled-Cavity portions are brazed copper structures and use electromagnetic quads. RF losses in the copper are 80 MW, with total rf power supplied by 52 klystrons. Additionally, the linac is to be upgraded to the 2- and 4-MW beam power levels with no increase in duty factor. The authors give an overview of the linac mechanical engineering effort and discuss the special challenges and status of the effort.

  18. A Long-Pulse Spallation Source at Los Alamos: Facility description and preliminary neutronic performance for cold neutrons

    SciTech Connect

    Russell, G.J.; Weinacht, D.J.; Pitcher, E.J.; Ferguson, P.D.

    1998-03-01

    The Los Alamos National Laboratory has discussed installing a new 1-MW spallation neutron target station in an existing building at the end of its 800-MeV proton linear accelerator. Because the accelerator provides pulses of protons each about 1 msec in duration, the new source would be a Long Pulse Spallation Source (LPSS). The facility would employ vertical extraction of moderators and reflectors, and horizontal extraction of the spallation target. An LPSS uses coupled moderators rather than decoupled ones. There are potential gains of about a factor of 6 to 7 in the time-averaged neutron brightness for cold-neutron production from a coupled liquid H{sub 2} moderator compared to a decoupled one. However, these gains come at the expense of putting ``tails`` on the neutron pulses. The particulars of the neutron pulses from a moderator (e.g., energy-dependent rise times, peak intensities, pulse widths, and decay constant(s) of the tails) are crucial parameters for designing instruments and estimating their performance at an LPSS. Tungsten is the reference target material. Inconel 718 is the reference target canister and proton beam window material, with Al-6061 being the choice for the liquid H{sub 2} moderator canister and vacuum container. A 1-MW LPSS would have world-class neutronic performance. The authors describe the proposed Los Alamos LPSS facility, and show that, for cold neutrons, the calculated time-averaged neutronic performance of a liquid H{sub 2} moderator at the 1-MW LPSS is equivalent to about 1/4th the calculated neutronic performance of the best liquid D{sub 2} moderator at the Institute Laue-Langevin reactor. They show that the time-averaged moderator neutronic brightness increases as the size of the moderator gets smaller.

  19. Final report on Seed Money Project 3210-0346: Feasibility study for californium cold neutron source

    SciTech Connect

    Alsmiller, R.G.; Henderson, D.L.; Montgomery, B.H.

    1988-10-01

    A study has been completed of the feasibility and cost of building a cold neutron source that is not dependent on a reactor or accelerator. The neutron source is provided by up to ten /sup 252/Cf capsules, each containing 50 mg of the isotope produced in the High-Flux Isotope Reactor. The neutrons are moderated by heavy water and liquid deuterium to attain, in practice, a peak cold neutron flux of 1.4 /times/ 10/sup 13/ neutrons/(m/sup 2//center dot/s). The new facility would be located in the TURF Californium Facility. The estimated cost of the Californium Cold Neutron Source Facility is $6.5 million. 6 figs., 1 tab.

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

    SciTech Connect

    Kim, Sang-Ho

    2009-01-01

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

  1. Materials Compatibility Studies for the Spallation Neutron Source

    SciTech Connect

    DiStefano, J.R.; Manneschmidt, E.T.; Pawel, S.J.

    1998-09-01

    The Spallation Neutron Source (SNS) is a high power facility for producing neutrons that utilizes flowing liquid mercury inside an austenitic stainless steel container as the target for a 1.0 GeV proton beam. The energy deposited in the target is transported by two separate mercury flow streams: one to transport heat in the interior target region and one to cool the stainless steel container. Three-dimensional computational fluid dynamics simulations have been performed to predict temperature, velocity, and pressure distributions in the target. Results have generally shown that the power deposited in the bulk mercury can be effectively transported with reasonable flow rates and the bulk mercury temperature should not exceed 160{deg}C. Assuming good thermal contact, the maximum stainless steel wall temperature should be 130 {deg}C. Type 316 SS has been selected as the container material for the mercury and consequences of exposure of 316 SS to radiation, thermal shock, thermal stress, cavitation and hot, flowing mercury are all being addressed by R&D programs. In addition, corrosion studies include evaluation of Inconel 718 because it has been successfully used in previous water cooled spallation neutron systems as a window material. With type 316 SS selected to contain the mercury target of the SNS, two types of compatibility issues have been examined: LME and temperature gradient mass transfer. Studies have shown that mercury does not easily wet type 316 SS below 275{deg}C. In the LME experiments, attempts were made to promote wetting of the steel by mercury either by adding gallium to the mercury or coating the specimen with a tin-silver solder that the mercury easily wets. The latter proved more reliable in establishing wetting, but there was no evidence of LME in any of the constant extension rate tensile tests either at 23 or 100 {deg}C. Inconel 718 also showed no change in room temperature properties when tested in mercwy or mercury-gallium. However, there was evidence that the fracture was less ductile. Preliminary evaluation of mass transfer of either type 304 SS, 316 SS, and Inconel 718 in mercury or mercury-gallium at 300-3500 C (maximum temperature) did not reveal significant effects. Two 5000 h thermal convection loop tests of type 316 SS are in progress, with specimens in both hot and cold test regions, at 300 and 240{deg}C, respectively.

  2. Computer simulations for rf design of a Spallation Neutron Source external antenna H- ion source.

    PubMed

    Lee, S W; Goulding, R H; Kang, Y W; Shin, K; Welton, R F

    2010-02-01

    Electromagnetic modeling of the multicusp external antenna H(-) ion source for the Spallation Neutron Source (SNS) has been performed in order to optimize high-power performance. During development of the SNS external antenna ion source, antenna failures due to high voltage and multicusp magnet holder rf heating concerns under stressful operating conditions led to rf characteristics analysis. In rf simulations, the plasma was modeled as an equivalent lossy metal by defining conductivity as sigma. Insulation designs along with material selections such as ferrite and Teflon could be included in the computer simulations to compare antenna gap potentials, surface power dissipations, and input impedance at the operating frequencies, 2 and 13.56 MHz. Further modeling and design improvements are outlined in the conclusion. PMID:20192395

  3. Multiplicity correlation between neutrons and gamma-rays emitted from SNM and non-SNM sources

    NASA Astrophysics Data System (ADS)

    Miloshevsky, Gennady; Hassanein, Ahmed

    2015-01-01

    The challenge in detection and identification of Special Nuclear Materials (SNM) is to discriminate between the time-correlated neutrons and gamma-rays emitted from SNM and those originating from non-correlated or differently-correlated environmental non-SNM sources. Time-correlated neutron and gamma-ray bursts can be generated by penetrating components of cosmic radiation. The characteristic features or attributes of correlated signatures can be revealed by analyzing the joint probability density functions (JPDFs) of various parameters of neutrons and gamma-rays. Monte Carlo simulations of SNM and cosmic-ray (non-SNM) sources of neutrons and gamma-rays are performed. For both SNM and non-SNM sources, energy-lifetime JPDF of neutrons, energy-lifetime JPDF of gamma-rays, and JPDFs of neutron-gamma-ray multiplicity are evaluated. Mean values, standard deviations, covariance and correlation are estimated. It is found that the number (multiplicity) of neutrons and gamma-rays emitted from an SNM source is moderately correlated (?0.48). The multiplicity of neutrons and gamma-rays generated by cosmic-ray showers at sea level is only weakly correlated (?-0.046). The exploitation of neutron-gamma-ray multiplicity correlation in detectors can provide a tool to discriminate non-SNM sources.

  4. Neutron guide optimisation for a time-of-flight neutron imaging instrument at the European Spallation Source.

    PubMed

    Hilger, A; Kardjilov, N; Manke, I; Zendler, C; Lieutenant, K; Habicht, K; Banhart, J; Strobl, M

    2015-01-12

    A neutron transport system for the planned imaging instrument ODIN at the future European Spallation Source (ESS) based on neutron optical components was designed and optimized. Different ways of prompt pulse suppression were studied. The spectral performance of the optimal neutron guide configuration is presented. In addition, the influence of the gaps in the guide system needed for the required chopper configuration was investigated. Given that the requirements for an imaging instrument located on a long guide system and hosting a complex chopper system are extremely demanding in terms of spectral and divergence needs, this study can be beneficial for a wide range of instruments in various ways. PMID:25835677

  5. Single-Volume Neutron Scatter Camera for High-Efficiency Neutron Imaging and Source Characterization. Year 2 of 3 Summary

    SciTech Connect

    Brubaker, Erik

    2015-10-01

    The neutron scatter camera (NSC), an imaging spectrometer for fission energy neutrons, is an established and proven detector for nuclear security applications such as weak source detection of special nuclear material (SNM), arms control treaty verification, and emergency response. Relative to competing technologies such as coded aperture imaging, time-encoded imaging, neutron time projection chamber, and various thermal neutron imagers, the NSC provides excellent event-by-event directional information for signal/background discrimination, reasonable imaging resolution, and good energy resolution. Its primary drawback is very low detection efficiency due to the requirement for neutron elastic scatters in two detector cells. We will develop a singlevolume double-scatter neutron imager, in which both neutron scatters can occur in the same large active volume. If successful, the efficiency will be dramatically increased over the current NSC cell-based geometry. If the detection efficiency approaches that of e.g. coded aperture imaging, the other inherent advantages of double-scatter imaging would make it the most attractive fast neutron detector for a wide range of security applications.

  6. Novel neutron sources at the Radiological Research Accelerator Facility

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Garty, G.; Marino, S. A.; Massey, T. N.; Randers-Pehrson, G.; Johnson, G. W.; Brenner, D. J.

    2012-03-01

    Since the 1960s, the Radiological Research Accelerator Facility (RARAF) has been providing researchers in biology, chemistry and physics with advanced irradiation techniques, using charged particles, photons and neutrons. We are currently developing a unique facility at RARAF, to simulate neutron spectra from an improvised nuclear device (IND), based on calculations of the neutron spectrum at 1.5 km from the epicenter of the Hiroshima atom bomb. This is significantly different from a standard fission spectrum, because the spectrum changes as the neutrons are transported through air, and is dominated by neutron energies between 0.05 and 8 MeV. This facility will be based on a mixed proton/deuteron beam impinging on a thick beryllium target. A second, novel facility under development is our new neutron microbeam. The neutron microbeam will, for the first time, provide a kinematically collimated neutron beam, 10-20 micron in diameter. This facility is based on a proton microbeam, impinging on a thin lithium target near the threshold of the 7Li(p,n)7Be reaction. This novel neutron microbeam will enable studies of neutron damage to small targets, such as single cells, individual organs within small animals or microelectronic components.

  7. Novel neutron sources at the Radiological Research Accelerator Facility

    PubMed Central

    Xu, Yanping; Garty, Guy; Marino, Stephen A.; Massey, Thomas N.; Randers-Pehrson, Gerhard; Johnson, Gary W.; Brenner, David J.

    2012-01-01

    Since the 1960s, the Radiological Research Accelerator Facility (RARAF) has been providing researchers in biology, chemistry and physics with advanced irradiation techniques, using charged particles, photons and neutrons. We are currently developing a unique facility at RARAF, to simulate neutron spectra from an improvised nuclear device (IND), based on calculations of the neutron spectrum at 1.5 km from the epicenter of the Hiroshima atom bomb. This is significantly different from a standard fission spectrum, because the spectrum changes as the neutrons are transported through air, and is dominated by neutron energies between 0.05 and 8 MeV. This facility will be based on a mixed proton/deuteron beam impinging on a thick beryllium target. A second, novel facility under development is our new neutron microbeam. The neutron microbeam will, for the first time, provide a kinematically collimated neutron beam, 10–20 micron in diameter. This facility is based on a Proton Microbeam, impinging on a thin lithium target near the threshold of the 7Li(p,n)7Be reaction. This novel neutron microbeam will enable studies of neutron damage to small targets, such as single cells, individual organs within small animals or microelectronic components. PMID:22545061

  8. Novel neutron sources at the Radiological Research Accelerator Facility.

    PubMed

    Xu, Yanping; Garty, Guy; Marino, Stephen A; Massey, Thomas N; Randers-Pehrson, Gerhard; Johnson, Gary W; Brenner, David J

    2012-03-16

    Since the 1960s, the Radiological Research Accelerator Facility (RARAF) has been providing researchers in biology, chemistry and physics with advanced irradiation techniques, using charged particles, photons and neutrons.We are currently developing a unique facility at RARAF, to simulate neutron spectra from an improvised nuclear device (IND), based on calculations of the neutron spectrum at 1.5 km from the epicenter of the Hiroshima atom bomb. This is significantly different from a standard fission spectrum, because the spectrum changes as the neutrons are transported through air, and is dominated by neutron energies between 0.05 and 8 MeV. This facility will be based on a mixed proton/deuteron beam impinging on a thick beryllium target.A second, novel facility under development is our new neutron microbeam. The neutron microbeam will, for the first time, provide a kinematically collimated neutron beam, 10-20 micron in diameter. This facility is based on a Proton Microbeam, impinging on a thin lithium target near the threshold of the (7)Li(p,n)(7)Be reaction. This novel neutron microbeam will enable studies of neutron damage to small targets, such as single cells, individual organs within small animals or microelectronic components. PMID:22545061

  9. Development of beryllium-based neutron target system with three-layer structure for accelerator-based neutron source for boron neutron capture therapy.

    PubMed

    Kumada, Hiroaki; Kurihara, Toshikazu; Yoshioka, Masakazu; Kobayashi, Hitoshi; Matsumoto, Hiroshi; Sugano, Tomei; Sakurai, Hideyuki; Sakae, Takeji; Matsumura, Akira

    2015-12-01

    The iBNCT project team with University of Tsukuba is developing an accelerator-based neutron source. Regarding neutron target material, our project has applied beryllium. To deal with large heat load and blistering of the target system, we developed a three-layer structure for the target system that includes a blistering mitigation material between the beryllium used as the neutron generator and the copper heat sink. The three materials were bonded through diffusion bonding using a hot isostatic pressing method. Based on several verifications, our project chose palladium as the intermediate layer. A prototype of the neutron target system was produced. We will verify that sufficient neutrons for BNCT treatment are generated by the device in the near future. PMID:26260448

  10. Report on the international workshop on cold moderators for pulsed neutron sources.

    SciTech Connect

    Carpenter, J. M.

    1999-01-06

    The International Workshop on Cold Moderators for Pulsed Neutron Sources resulted from the coincidence of two forces. Our sponsors in the Materials Sciences Branch of DOE's Office of Energy Research and the community of moderator and neutron facility developers both realized that it was time. The Neutron Sources Working Group of the Megascience Forum of the Organization for Economic Cooperation and Development offered to contribute its support by publishing the proceedings, which with DOE and Argonne sponsorship cemented the initiative. The purposes of the workshop were: to recall and improve the theoretical groundwork of time-dependent neutron thermalization; to pose and examine the needs for and benefits of cold moderators for neutron scattering and other applications of pulsed neutron sources; to summarize experience with pulsed source, cold moderators, their performance, effectiveness, successes, problems and solutions, and the needs for operational data; to compile and evaluate new ideas for cold moderator materials and geometries; to review methods of measuring and characterizing pulsed source cold moderator performance; to appraise methods of calculating needed source characteristics and to evaluate the needs and prospects for improvements; to assess the state of knowledge of data needed for calculating the neutronic and engineering performance of cold moderators; and to outline the needs for facilities for testing various aspects of pulsed source cold moderator performance.

  11. Advanced neutron source reactor probabilistic flow blockage assessment

    SciTech Connect

    Ramsey, C.T.

    1995-08-01

    The Phase I Level I Probabilistic Risk Assessment (PRA) of the conceptual design of the Advanced Neutron Source (ANS) Reactor identified core flow blockage as the most likely internal event leading to fuel damage. The flow blockage event frequency used in the original ANS PRA was based primarily on the flow blockage work done for the High Flux Isotope Reactor (HFIR) PRA. This report examines potential flow blockage scenarios and calculates an estimate of the likelihood of debris-induced fuel damage. The bulk of the report is based specifically on the conceptual design of ANS with a 93%-enriched, two-element core; insights to the impact of the proposed three-element core are examined in Sect. 5. In addition to providing a probability (uncertainty) distribution for the likelihood of core flow blockage, this ongoing effort will serve to indicate potential areas of concern to be focused on in the preliminary design for elimination or mitigation. It will also serve as a loose-parts management tool.

  12. Reactor installation and maintenance for the Advanced Neutron Source

    SciTech Connect

    Smith, B.R.

    1993-10-01

    Advanced Neutron Source (ANS) reactor assembly components have been modeled in great detail in IGRIP in order to realistically simulate preliminary installation and maintenance processes. Animation of these processes has been captured in a 15-minute video with narration. Approximately 90% of the parts were initially translated from CADAM (a two-dimensional drawing package) to IGRIP and then revolved or extruded. IGRIP`s IGES translator greatly reduced the time required to perform this operation. The interfacing of devices in the work cell has identified numerous design inconsistencies. Most of the modeled reactor components are devices with a single degree of freedom (DOF) however, some of the slanted experiments required 6 DOF so that they could be removed at an angle in order to clear the reflector vessel flanges. IGRIP`s collision detection feature proved to be extremely helpful in determining interferences when removing the experiments. The combination of three-dimensional visualization and collision detection allows engineers to clearly and easily visualize potential design problems before the construction phase of the project.

  13. Characterization of pulsed (plasma focus) neutron source with image plate and application to neutron radiography

    SciTech Connect

    Andola, Sanjay; Niranjan, Ram; Rout, R. K.; Kaushik, T. C.; Gupta, S. C.; Shaikh, A. M.

    2013-02-05

    Plasma focus device of Mather type developed in house has been used first time for neutron radiography of different objects. The device gives (1.2{+-}0.3) Multiplication-Sign 10{sup 9} neutrons per pulse produced by D-D fusion reaction with a pulse width of 50{+-}5 ns. The method involves exposing sample to be radiographed to thermalized D-D neutrons and recording the image on Fuji-film BAS-ND image plates. The thermal neutron component of the moderated beam was estimated using two image plates: a conventional IP for X-rays and gamma rays, and an IP doped with Gd for detecting neutrons.

  14. Advanced Neutron Source Cross Section Libraries (ANSL-V): ENDF/B-V based multigroup cross-section libraries for advanced neutron source (ANS) reactor studies

    SciTech Connect

    Ford, W.E. III; Arwood, J.W.; Greene, N.M.; Moses, D.L.; Petrie, L.M.; Primm, R.T. III; Slater, C.O.; Westfall, R.M.; Wright, R.Q.

    1990-09-01

    Pseudo-problem-independent, multigroup cross-section libraries were generated to support Advanced Neutron Source (ANS) Reactor design studies. The ANS is a proposed reactor which would be fueled with highly enriched uranium and cooled with heavy water. The libraries, designated ANSL-V (Advanced Neutron Source Cross Section Libraries based on ENDF/B-V), are data bases in AMPX master format for subsequent generation of problem-dependent cross-sections for use with codes such as KENO, ANISN, XSDRNPM, VENTURE, DOT, DORT, TORT, and MORSE. Included in ANSL-V are 99-group and 39-group neutron, 39-neutron-group 44-gamma-ray-group secondary gamma-ray production (SGRP), 44-group gamma-ray interaction (GRI), and coupled, 39-neutron group 44-gamma-ray group (CNG) cross-section libraries. The neutron and SGRP libraries were generated primarily from ENDF/B-V data; the GRI library was generated from DLC-99/HUGO data, which is recognized as the ENDF/B-V photon interaction data. Modules from the AMPX and NJOY systems were used to process the multigroup data. Validity of selected data from the fine- and broad-group neutron libraries was satisfactorily tested in performance parameter calculations.

  15. Development of Measurement Methods for Detection of Special Nuclear Materials using D-D Pulsed Neutron Source

    NASA Astrophysics Data System (ADS)

    Misawa, Tsuyoshi; Takahashi, Yoshiyuki; Yagi, Takahiro; Pyeon, Cheol Ho; Kimura, Masaharu; Masuda, Kai; Ohgaki, Hideaki

    2015-10-01

    For detection of hidden special nuclear materials (SNMs), we have developed an active neutron-based interrogation system combined with a D-D fusion pulsed neutron source and a neutron detection system. In the detection scheme, we have adopted new measurement techniques simultaneously; neutron noise analysis and neutron energy spectrum analysis. The validity of neutron noise analysis method has been experimentally studied in the Kyoto University Critical Assembly (KUCA), and was applied to a cargo container inspection system by simulation.

  16. Microwave Ion Source and Beam Injection for an Accelerator-drivenNeutron Source

    SciTech Connect

    Vainionpaa, J.H.; Gough, R.; Hoff, M.; Kwan, J.W.; Ludewigt,B.A.; Regis, M.J.; Wallig, J.G.; Wells, R.

    2007-02-15

    An over-dense microwave driven ion source capable ofproducing deuterium (or hydrogen) beams at 100-200 mA/cm2 and with atomicfraction>90 percent was designed and tested with an electrostaticlow energy beam transport section (LEBT). This ion source wasincorporatedinto the design of an Accelerator Driven Neutron Source(ADNS). The other key components in the ADNS include a 6 MeV RFQaccelerator, a beam bending and scanning system, and a deuterium gastarget. In this design a 40 mA D+ beam is produced from a 6 mm diameteraperture using a 60 kV extraction voltage. The LEBT section consists of 5electrodes arranged to form 2 Einzel lenses that focus the beam into theRFQ entrance. To create the ECR condition, 2 induction coils are used tocreate ~; 875 Gauss on axis inside the source chamber. To prevent HVbreakdown in the LEBT a magnetic field clamp is necessary to minimize thefield in this region. Matching of the microwave power from the waveguideto the plasma is done by an autotuner. We observed significantimprovement of the beam quality after installing a boron nitride linerinside the ion source. The measured emittance data are compared withPBGUNS simulations.

  17. Control system for the Spallation Neutron Source H{sup -} source test facility Allison scanner

    SciTech Connect

    Long, C. D.; Stockli, M. P.; Gorlov, T. V.; Han, B.; Murray, S. N.; Pennisi, T. R.

    2010-02-15

    Spallation Neutron Source is currently in progress of a multiyear plan to ramp ion beam power to the initial design power of 1.4 MW. Key to reaching this goal is understanding and improving the operation of the H{sup -} ion source. An Allison scanner was installed on the ion source in the test facility to support this improvement. This paper will discuss the hardware and the software control system of the installed Allison scanner. The hardware for the system consists of several parts. The heart of the system is the scanner head, complete with associated bias plates, slits, and signal detector. There are two analog controlled high voltage power supplies to bias the plates in the head, and a motor with associated controller to position the head in the beam. A multifunction data acquisition card reads the signals from the signal detector, as well as supplies the analog voltage control for the power supplies. To synchronize data acquisition with the source, the same timing signal that is used to trigger the source itself is used to trigger data acquisition. Finally, there is an industrial personal computer to control the rest of the hardware. Control software was developed using National Instruments LABVIEW, and consists of two parts: a data acquisition program to control the hardware and a stand alone application for offline user data analysis.

  18. Measurement of the 250Cf component in a 252Cf neutron source at KRISS.

    PubMed

    Kim, Jungho; Park, Hyeonseo; Choi, Kil-Oung

    2014-10-01

    Neutron emission rate measurements have been carried out at the Korea Research Institute of Standards and Science using a manganese sulphate bath system for (252)Cf and (241)Am-Be sources since 2004. The relative measurement method was chosen in 2012, and the neutron emission rates agreed with those by the absolute measurement method within uncertainties. The neutron emission rate of an old (252)Cf source has been measured three times: in 2004, 2009 and 2012. The (250)Cf component was fitted to a double-exponential function of (252)Cf+(250)Cf, and the ratio of the (250)Cf component to the (252)Cf component was estimated to be 7.8 % in 2004 and 46.8 % in 2012. Underestimation of the neutron emission rates of old (252)Cf sources can be corrected if the neutron emission rate of the (250)Cf component is taken into account. PMID:24344350

  19. A laser-induced repetitive fast neutron source applied for gold activation analysis

    SciTech Connect

    Lee, Sungman; Park, Sangsoon; Lee, Kitae; Cha, Hyungki

    2012-12-15

    A laser-induced repetitively operated fast neutron source was developed for applications in laser-driven nuclear physics research. The developed neutron source, which has a neutron yield of approximately 4 Multiplication-Sign 10{sup 5} n/pulse and can be operated up to a pulse repetition rate of 10 Hz, was applied for a gold activation analysis. Relatively strong delayed gamma spectra of the activated gold were measured at 333 keV and 355 keV, and proved the possibility of the neutron source for activation analyses. In addition, the nuclear reactions responsible for the measured gamma spectra of gold were elucidated by the 14 MeV fast neutrons resulting from the D(t,n)He{sup 4} nuclear reaction, for which the required tritium originated from the primary fusion reaction, D(d,p)T{sup 3}.

  20. ETHERNES: A new design of radionuclide source-based thermal neutron facility with large homogeneity area.

    PubMed

    Bedogni, R; Sacco, D; Gómez-Ros, J M; Lorenzoli, M; Gentile, A; Buonomo, B; Pola, A; Introini, M V; Bortot, D; Domingo, C

    2016-01-01

    A new thermal neutron irradiation facility based on an (241)Am-Be source embedded in a polyethylene moderator has been designed, and is called ETHERNES (Extended THERmal NEutron Source). The facility shows a large irradiation cavity (45cm×45cm square section, 63cm in height), which is separated from the source by means of a polyethylene sphere acting as shadowing object. Taking advantage of multiple scattering of neutrons with the walls of this cavity, the moderation process is especially effective and allows obtaining useful thermal fluence rates from 550 to 800cm(-2)s(-1) with a source having nominal emission rate 5.7×10(6)s(-1). Irradiation planes parallel to the cavity bottom have been identified. The fluence rate across a given plane is as uniform as 3% (or better) in a disk with 30cm (or higher) diameter. In practice, the value of thermal fluence rate simply depends on the height from the cavity bottom. The thermal neutron spectral fraction ranges from 77% up to 89%, depending on the irradiation plane. The angular distribution of thermal neutrons is roughly isotropic, with a slight prevalence of directions from bottom to top of the cavity. The mentioned characteristics are expected to be attractive for the scientific community involved in neutron metrology, neutron dosimetry and neutron detector testing. PMID:26516990

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

    SciTech Connect

    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.

  2. Fabrication and characterization of the source grating for visibility improvement of neutron phase imaging with gratings

    SciTech Connect

    Kim, Jongyul; Lee, Kye Hong; Lim, Chang Hwy; Kim, Taejoo; Ahn, Chi Won; Cho, Gyuseong; Lee, Seung Wook

    2013-06-15

    The fabrication of gratings including metal deposition processes for highly neutron absorbing lines is a critical issue to achieve a good visibility of the grating-based phase imaging system. The source grating for a neutron Talbot-Lau interferometer is an array of Gadolinium (Gd) structures that are generally made by sputtering, photo-lithography, and chemical wet etching. However, it is very challenging to fabricate a Gd structure with sufficient neutron attenuation of approximately more than 20 {mu}m using a conventional metal deposition method because of the slow Gd deposition rate, film stress, high material cost, and so on. In this article, we fabricated the source gratings for neutron Talbot-Lau interferometers by filling the silicon structure with Gadox particles. The new fabrication method allowed us a very stable and efficient way to achieve a much higher Gadox filled structure than a Gd film structure, and is even more suitable for thermal polychromatic neutrons, which are more difficult to stop than cold neutrons. The newly fabricated source gratings were tested at the polychromatic thermal neutron grating interferometer system of HANARO at the Korea Atomic Energy Research Institute, and the visibilities and images from the neutron phase imaging system with the new source gratings were compared with those fabricated by a Gd deposition method.

  3. Neutrons absorbed dose rate calculations for interstitial brachytherapy with 252Cf sources

    NASA Astrophysics Data System (ADS)

    Paredes, L.; Azorín, J.; Balcázar, M.; Francois, J. L.

    2007-09-01

    The AAPM TG-43 protocol was used to evaluate the neutron absorbed dose rate from 252Cf sources for two tissue substitute materials, five normal tissues and six malignant tumours. Three 252Cf source models (AT, VariSource and ?Selectron) were simulated using the Monte Carlo MCNPX code in spherical geometry for obtaining the following factors: (a) conversion coefficient of neutron air kerma strength, (b) neutron dose rate constant, (c) neutron radial dose function, (d) geometry function, (e) anisotropy function and (f) neutron absorbed dose rate. For the 252Cf AT source and a Watt fission spectrum, the calculated reference neutron dose rate in water was D(r0,?0)=1.916 cGy h -1 ?g -1. The results for the reference neutron dose rate in normal tissues and malignant tumours show how small variations in their elemental composition produce variations in the neutron absorbed dose rate up to 14.9% and 8.4%, respectively, when water and muscle are the reference medium.

  4. Energyangle correlation of neutrons and gamma-rays emitted from an HEU source

    E-print Network

    Harilal, S. S.

    Energy­angle correlation of neutrons and gamma-rays emitted from an HEU source G. Miloshevsky n , A and gamma-rays Joint and marginal probability density functions Covariance and correlation a b s t r a c t Special Nuclear Materials (SNM) yield very unique fission signatures, namely correlated neutrons and gamma-rays

  5. H{sup -} radio frequency source development at the Spallation Neutron Source

    SciTech Connect

    Welton, R. F.; Gawne, K. R.; Han, B. X.; Murray, S. N.; Pennisi, T. R.; Roseberry, R. T.; Santana, M.; Stockli, M. P.; Dudnikov, V. G.; Turvey, M. W.

    2012-02-15

    The Spallation Neutron Source (SNS) now routinely operates nearly 1 MW of beam power on target with a highly persistent {approx}38 mA peak current in the linac and an availability of {approx}90%. H{sup -} beam pulses ({approx}1 ms, 60 Hz) are produced by a Cs-enhanced, multicusp ion source closely coupled with an electrostatic low energy beam transport (LEBT), which focuses the 65 kV beam into a radio frequency quadrupole accelerator. The source plasma is generated by RF excitation (2 MHz, {approx}60 kW) of a copper antenna that has been encased with a thickness of {approx}0.7 mm of porcelain enamel and immersed into the plasma chamber. The ion source and LEBT normally have a combined availability of {approx}99%. Recent increases in duty-factor and RF power have made antenna failures a leading cause of downtime. This report first identifies the physical mechanism of antenna failure from a statistical inspection of {approx}75 antennas which ran at the SNS, scanning electron microscopy studies of antenna surface, and cross sectional cuts and analysis of calorimetric heating measurements. Failure mitigation efforts are then described which include modifying the antenna geometry and our acceptance/installation criteria. Progress and status of the development of the SNS external antenna source, a long-term solution to the internal antenna problem, are then discussed. Currently, this source is capable of delivering comparable beam currents to the baseline source to the SNS and, an earlier version, has briefly demonstrated unanalyzed currents up to {approx}100 mA (1 ms, 60 Hz) on the test stand. In particular, this paper discusses plasma ignition (dc and RF plasma guns), antenna reliability, magnet overheating, and insufficient beam persistence.

  6. Model-Based Least Squares Reconstruction of Coded Source Neutron Radiographs: Integrating the ORNL HFIR CG1D Source Model

    SciTech Connect

    Santos-Villalobos, Hector J; Gregor, Jens; Bingham, Philip R

    2014-01-01

    At the present, neutron sources cannot be fabricated small and powerful enough in order to achieve high resolution radiography while maintaining an adequate flux. One solution is to employ computational imaging techniques such as a Magnified Coded Source Imaging (CSI) system. A coded-mask is placed between the neutron source and the object. The system resolution is increased by reducing the size of the mask holes and the flux is increased by increasing the size of the coded-mask and/or the number of holes. One limitation of such system is that the resolution of current state-of-the-art scintillator-based detectors caps around 50um. To overcome this challenge, the coded-mask and object are magnified by making the distance from the coded-mask to the object much smaller than the distance from object to detector. In previous work, we have shown via synthetic experiments that our least squares method outperforms other methods in image quality and reconstruction precision because of the modeling of the CSI system components. However, the validation experiments were limited to simplistic neutron sources. In this work, we aim to model the flux distribution of a real neutron source and incorporate such a model in our least squares computational system. We provide a full description of the methodology used to characterize the neutron source and validate the method with synthetic experiments.

  7. High Field Pulsed Magnets for Neutron Scattering at the Spallation Neutron Source

    NASA Astrophysics Data System (ADS)

    Granroth, G. E.; Lee, J.; Fogh, E.; Christensen, N. B.; Toft-Petersen, R.; Nojiri, H.

    2015-03-01

    A High Field Pulsed Magnet (HFPM) setup, is in use at the Spallation Nuetron Source(SNS), Oak Ridge National Laboratory. With this device, we recently measured the high field magnetic spin structure of LiNiPO4. The results of this study will be highlighted as an example of possible measurements that can be performed with this device. To further extend the HFPM capabilities at SNS, we have learned to design and wind these coils in house. This contribution will summarize the magnet coil design optimization procedure. Specifically by varying the geometry of the multi-layer coil, we arrive at a design that balances the maximum field strength, neutron scattering angle, and the field homogeneity for a specific set of parameters. We will show that a 6.3kJ capacitor bank, can provide a magnetic field as high as 30T for a maximum scattering angle around 40° with homogeneity of +/- 4 % in a 2mm diameter spherical volume. We will also compare the calculations to measurements from a recently wound test coil. This work was supported in part by the Lab Directors' Research and Development Fund of ORNL.

  8. Intense Pulsed Neutron Source progress report for 1991

    SciTech Connect

    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.

  9. Intense Pulsed Neutron Source progress report for 1991

    SciTech Connect

    Not Available

    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.

  10. Designing and testing the neutron source deployment system and calibration plan for a dark matter detector

    E-print Network

    Westerdale, Shawn (Shawn S.)

    2011-01-01

    In this thesis, we designed and tested a calibration and deployment system for the MiniCLEAN dark matter detector. The deployment system uses a computer controlled winch to lower a canister containing a neutron source into ...

  11. Proceedings of the 10th meeting of the international collaboration on advanced neutron sources

    SciTech Connect

    Hyer, D.K.

    1989-03-01

    This report contains papers from the 10th meeting of the International Collaboration on Advanced Neutron Sources. Two general types of workshops are discussed, instrument and target-station. Individual papers are indexed separately elsewhere. (LSP)

  12. Monte Carlo calculation of skyshine'' neutron dose from ALS (Advanced Light Source)

    SciTech Connect

    Moin-Vasiri, M.

    1990-06-01

    This report discusses the following topics on skyshine'' neutron dose from ALS: Sources of radiation; ALS modeling for skyshine calculations; MORSE Monte-Carlo; Implementation of MORSE; Results of skyshine calculations from storage ring; and Comparison of MORSE shielding calculations.

  13. Optimization of a moderator assembly for use in an accelerator-based neutron source for boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Woollard, Jeffrey Earl

    In this dissertation, the development and application of in-phantom neutron field optimization parameters for use in evaluating neutron fields for Boron Neutron Capture Therapy (BNCT) is presented. These parameters are based on dose rate distributions in a head phantom and include the effects of fractionation and an energy dependent normal-tissue neutron RBE. As a step in the development of these parameters, a methodology for calculating the energy dependent normal-tissue neutron RBE, RBE(Esbn), was developed. This methodology was used to obtain reasonable estimates for the RBE of neutrons, as a function of neutron energy, for skeletal muscle and brain tissue. Additionally, a sensitivity analysis was performed to examine the robustness of the calculations of RBE(Esbn) to necessary assumptions regarding the level of cell-survival at tolerance for brain. This analysis showed that differences in the RBE-dose rate as a function of depth in an ellipsoidal head phantom, as a result of different assumptions regarding the level of cell-survival at tolerance, were negligible, thus increasing our confidence in our mathematical method. The in-phantom neutron field optimization parameters were used to evaluate the neutron fields produced by several potential moderator assemblies and to determine the optimum moderator assembly for use in our Accelerator-Based Neutron Source (ABNS) for BNCT. Based on a comparison of the calculated in-phantom neutron field optimization parameters, for a single irradiation from the superior aspect, a 10 mA proton beam current, and the specified treatment parameters, a BeO-Lisb2COsb3 moderator assembly, with a 20 cm thick BeO moderator, was found to be the optimum moderator assembly for use in the ABNS. The second best moderator assembly was a Dsb2O-Lisb2COsb3 moderator assembly with a 25 cm thick Dsb2O moderator. An optimization analysis, based on in-air optimization parameters, was also performed on the same moderator assemblies considered in the in-phantom moderator assembly optimization analysis. This analysis concluded that the moderator assemblies shown as optimum in the in-phantom moderator assembly optimization analysis, were also the optimum moderator assemblies based on the in-air parameters. This indicates that both types of parameters agree on the optimal neutron field for use in an ABNS for BNCT.

  14. Prompt-gamma neutron activation analysis system design: effects of D-T versus D-D neutron generator source selection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Prompt-gamma neutron activation analysis (PGNAA) is used for the non-invasive measurement of human body composition. Advancements in portable, compact neutron generator design have made those devices attractive as neutron sources. Two distinct generators are available: D-D with 2.5 MeV, and D-T wi...

  15. Prompt-gamma neutron activation analysis system design: Effects of D-T versus D-D neutron generator source selection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Prompt-gamma neutron activation (PGNA) analysis is used for the non-invasive measurement of human body composition. Advancements in portable, compact neutron generator design have made those devices attractive as neutron sources. Two distinct generators are available: D-D with 2.5 MeV and D-T with...

  16. Overview of the Conceptual Design of the Future VENUS Neutron Imaging Beam Line at the Spallation Neutron Source

    NASA Astrophysics Data System (ADS)

    Bilheux, Hassina; Herwig, Ken; Keener, Scott; Davis, Larry

    VENUS (Versatile Neutron Imaging Beam line at the Spallation Neutron Source) will be a world-class neutron-imaging instrument that will uniquely utilize the Spallation Neutron Source (SNS) time-of-flight (TOF) capabilities to measure and characterize objects across several length scales (mm to ?m). When completed, VENUS will provide academia, industry and government laboratories with the opportunity to advance scientific research in areas such as energy, materials, additive manufacturing, geosciences, transportation, engineering, plant physiology, biology, etc. It is anticipated that a good portion of the VENUS user community will have a strong engineering/industrial research focus. Installed at Beam line 10 (BL10), VENUS will be a 25-m neutron imaging facility with the capability to fully illuminate (i.e., umbra illumination) a 20 cm x 20 cm detector area. The design allows for a 28 cm x 28 cm field of view when using the penumbra to 80% of the full illumination flux. A sample position at 20 m will be implemented for magnification measurements. The optical components are comprised of a series of selected apertures, T0 and bandwidth choppers, beam scrapers, a fast shutter to limit sample activation, and flight tubes filled with Helium. Techniques such as energy selective, Bragg edge and epithermal imaging will be available at VENUS.

  17. Characterization of a novel, short pulse laser-driven neutron source

    SciTech Connect

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

    2013-05-15

    We present a full characterization of a short pulse laser-driven neutron source. Neutrons are produced by nuclear reactions of laser-driven ions deposited in a secondary target. The emission of neutrons is a superposition of an isotropic component into 4? and a forward directed, jet-like contribution, with energies ranging up to 80 MeV. A maximum flux of 4.4 × 10{sup 9} neutrons/sr has been observed and used for fast neutron radiography. On-shot characterization of the ion driver and neutron beam has been done with a variety of different diagnostics, including particle detectors, nuclear reaction, and time-of-flight methods. The results are of great value for future optimization of this novel technique and implementation in advanced applications.

  18. Ion Acceleration by Magnetic Pinch Instabilities- Powerful Neutron Sources

    NASA Astrophysics Data System (ADS)

    Hayes, Anna; Li, Hui

    2014-10-01

    Since the 1950s pinch discharges with deuterium gas have been known to produce large neutron bursts. During these early quests for laboratory fusion it was initially believed that the heat produced in the pinch led to sufficently high temperatures that these neutrons resulted from thermonuclear (TN) burn. However, a series of careful measurements led by Stirling Colgate was carried out to show that these neutrons did not result form TN burn. Rather, they resulted from an m = 0 sausage mode instability that accelerated the ions, causing beam-target interactions. Today, this same mechanism is used in dense plasma focus machines to generate intense neutron pulses for neutron activation experiments. One such experiment, to test the citicality of aging plutonium, is currently being planned at the Nevada Test Site. Helping to characterize the neutrons from the dense palsma focus to be used in this large experiment was the last applied physics project that Stirling work on. In this talk we will summarize the physics issues involved both in the original discovery in the 1950s and in today's experiments.

  19. Separation of beam and electrons in the spallation neutron source H{sup -} ion source

    SciTech Connect

    Whealton, J.H.; Raridon, R.J.; Leung, K.N.

    1997-12-01

    The Spallation Neutron Source (SNS) requires an ion source producing an H{sup {minus}} beam with a peak current of 35mA at a 6.2 percent duty factor. For the design of this ion source, extracted electrons must be transported and dumped without adversely affecting the H{sup {minus}} beam optics. Two issues are considered: (1) electron containment transport and controlled removal; and (2) first-order H{sup {minus}} 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.

  20. Preliminary probabilistic design accident evaluation of the cold source facilities of the advanced neutron source

    SciTech Connect

    Harrington, R.M.; Ramsey, C.T.

    1995-08-01

    Consistent with established Advanced Neutron Source (ANS) project policy for the use of probabilistic risk assessment (PRA) in design, a task has been established to use PRA techniques to help guide the design and safety analysis of the ANS cold sources. The work discussed in this report is the first formal output of the cold source PRA task. The major output at this stage is a list of design basis accidents, categorized into approximate frequency categories. This output is expected to focus attention on continued design work to define and optimize the design such that design basis accidents are better defined and have acceptable outcomes. Categorizing the design basis events (DBEs) into frequency categories should prove helpful because it will allow appropriate acceptance criteria to be applied. Because the design of the cold source is still proceeding, it is beyond the scope of this task to produce detailed event probability calculations or even, in some cases, detailed event sequence definitions. That work would take place as a logically planned follow-on task, to be completed as the design matures. Figure 1.1 illustrates the steps that would typically be followed in selecting design basis accidents with the help of PRA. Only those steps located above the dashed line on Fig. 1.1 are included in the scope of the present task. (Only an informal top-level failure modes and effects analysis was done.) With ANS project closeout expected in the near future, the scope of this task has been abbreviated somewhat beyond the state of available design information on the ANS cold sources, or what could be achieved in a reasonable time. This change was necessary to ensure completion before the closeout and because the in-depth analytical support necessary to define fully some of the accidents has already been curtailed.

  1. Neutron intensity monitor with activation foil for p-Li neutron source for BNCT - Feasibility test of the concept.

    PubMed

    Murata, Isao; Otani, Yuki; Sato, Fuminobu

    2015-12-01

    Proton-lithium (p-Li) reaction is being examined worldwide as a candidate nuclear production reaction for accelerator based neutron source (ABNS) for BNCT. In this reaction, the emitted neutron energy is not so high, below 1MeV, and especially in backward angles the energy is as low as about 100keV. The intensity measurement was thus known to be difficult so far. In the present study, a simple method was investigated to monitor the absolute neutron intensity of the p-Li neutron source by employing the foil activation method based on isomer production reactions in order to cover around several hundreds keV. As a result of numerical examination, it was found that (107)Ag, (115)In and (189)Os would be feasible. Their features found out are summarized as follows: (107)Ag: The most convenient foil, since the half life is short. (115)In: The accuracy is the best at 0°, though it cannot be used for backward angles. And (189)Os: Suitable nuclide which can be used in backward angles, though the gamma-ray energy is a little too low. These would be used for p-Li source monitoring depending on measuring purposes in real BNCT scenes. PMID:26242557

  2. A precise method to determine the activity of a weak neutron source using a germanium detector

    E-print Network

    M. J. M. Duke; A. L. Hallin; C. B. Krauss; P. Mekarski; L. Sibley

    2015-06-17

    A standard high purity germanium detector (HPGe) was used to determine the neutron activity of a weak americium-beryllium (AmBe) neutron source. Gamma rays were created through 27Al(n,n'), 27Al(n,gamma) and 1H(n,gamma) reactions induced by the neutrons on aluminum and acrylic disks. A Monte Carlo simulation was developed to model the efficiency of the detector system. The activity of our neutron source was determined to be 305.6 +/- 4.9 n/s. The result is consistent for the different gamma rays and was verified using additional simulations and measurements of the 4483 keV gamma ray produced directly from the AmBe source.

  3. A precise method to determine the activity of a weak neutron source using a germanium detector

    E-print Network

    Duke, M J M; Krauss, C B; Mekarski, P; Sibley, L

    2015-01-01

    A standard high purity germanium detector (HPGe) was used to determine the neutron activity of a weak americium-beryllium (AmBe) neutron source. Gamma rays were created through 27Al(n,n'), 27Al(n,gamma) and 1H(n,gamma) reactions induced by the neutrons on aluminum and acrylic disks. A Monte Carlo simulation was developed to model the efficiency of the detector system. The activity of our neutron source was determined to be 305.6 +/- 4.9 n/s. The result is consistent for the different gamma rays and was verified using additional simulations and measurements of the 4483 keV gamma ray produced directly from the AmBe source.

  4. Development of a Time-tagged Neutron Source for SNM Detection

    DOE PAGESBeta

    Ji, Qing; Ludewigt, Bernhard; Wallig, Joe; Waldron, Will; Tinsley, Jim

    2015-06-18

    Associated particle imaging (API) is a powerful technique for special nuclear material (SNM) detection and characterization of fissile material configurations. A sealed-tube neutron generator has been under development by Lawrence Berkeley National Laboratory to reduce the beam spot size on the neutron production target to 1 mm in diameter for a several-fold increase in directional resolution and simultaneously increases the maximum attainable neutron flux. A permanent magnet 2.45 GHz microwave-driven ion source has been adopted in this time-tagged neutron source. This type of ion source provides a high plasma density that allows the use of a sub-millimeter aperture for themore »extraction of a sufficient ion beam current and lets us achieve a much reduced beam spot size on target without employing active focusing. The design of this API generator uses a custom-made radial high voltage insulator to minimize source to neutron production target distance and to provide for a simple ion source cooling arrangement. Preliminary experimental results showed that more than 100 µA of deuterium ions have been extracted, and the beam diameter on the neutron production target is around 1 mm.« less

  5. Development of a Time-tagged Neutron Source for SNM Detection

    SciTech Connect

    Ji, Qing; Ludewigt, Bernhard; Wallig, Joe; Waldron, Will; Tinsley, Jim

    2015-06-18

    Associated particle imaging (API) is a powerful technique for special nuclear material (SNM) detection and characterization of fissile material configurations. A sealed-tube neutron generator has been under development by Lawrence Berkeley National Laboratory to reduce the beam spot size on the neutron production target to 1 mm in diameter for a several-fold increase in directional resolution and simultaneously increases the maximum attainable neutron flux. A permanent magnet 2.45 GHz microwave-driven ion source has been adopted in this time-tagged neutron source. This type of ion source provides a high plasma density that allows the use of a sub-millimeter aperture for the extraction of a sufficient ion beam current and lets us achieve a much reduced beam spot size on target without employing active focusing. The design of this API generator uses a custom-made radial high voltage insulator to minimize source to neutron production target distance and to provide for a simple ion source cooling arrangement. Preliminary experimental results showed that more than 100 µA of deuterium ions have been extracted, and the beam diameter on the neutron production target is around 1 mm.

  6. Neutron generator for BNCT based on high current ECR ion source with gyrotron plasma heating.

    PubMed

    Skalyga, V; Izotov, I; Golubev, S; Razin, S; Sidorov, A; Maslennikova, A; Volovecky, A; Kalvas, T; Koivisto, H; Tarvainen, O

    2015-12-01

    BNCT development nowadays is constrained by a progress in neutron sources design. Creation of a cheap and compact intense neutron source would significantly simplify trial treatments avoiding use of expensive and complicated nuclear reactors and accelerators. D-D or D-T neutron generator is one of alternative types of such sources for. A so-called high current quasi-gasdynamic ECR ion source with plasma heating by millimeter wave gyrotron radiation is suggested to be used in a scheme of D-D neutron generator in the present work. Ion source of that type was developed in the Institute of Applied Physics of Russian Academy of Sciences (Nizhny Novgorod, Russia). It can produce deuteron ion beams with current density up to 700-800mA/cm(2). Generation of the neutron flux with density at the level of 7-8·10(10)s(-1)cm(-2) at the target surface could be obtained in case of TiD2 target bombardment with deuteron beam accelerated to 100keV. Estimations show that it is enough for formation of epithermal neutron flux with density higher than 10(9)s(-1)cm(-)(2) suitable for BNCT. Important advantage of described approach is absence of Tritium in the scheme. First experiments performed in pulsed regime with 300mA, 45kV deuteron beam directed to D2O target demonstrated 10(9)s(-)(1) neutron flux. This value corresponds to theoretical estimations and proofs prospects of neutron generator development based on high current quasi-gasdynamic ECR ion source. PMID:26302662

  7. General Electric PETtrace cyclotron as a neutron source for boron neutron capture therapy 

    E-print Network

    Bosko, Andrey

    2005-11-01

    of various thicknesses were considered: light water, carbon, heavy water, and FluentalTM. The fluence rate tally was used to calculate photon and neutron dose, by applying fluence rate-to-dose conversion factors. Fifteen different geometries were considered...

  8. Neutron-source characterization for fusion-materials studies

    SciTech Connect

    Greenwood, L.R.

    1981-06-01

    Neutron-flux and energy-spectrum measurements are conducted for all major fusion-materials irradiation facilities, including fission reactors and accelerators. Dosimetry-characterization experiments and integral cross section measurements have been performed. Multiple activation and helium-production measurements are performed routinely to provide materials experimenters with neutron-exposure parameters including fluence, spectrum, displacements, gas production, and transmutation with typical accuracies of 10 to 15%. Such data are crucial to the fusion-materials program in order to correlate materials-property changes between irradiations and facilities and to confidently predict the performance of materials in fusion reactors.

  9. Influence of multiple sources on the two-neutron correlation function in Ni-induced, intermediate energy, heavy ion reactions

    NASA Astrophysics Data System (ADS)

    Ghetti, R.; Helgesson, J.; Colonna, N.; Jakobsson, B.; Anzalone, A.; Bellini, V.; Carlèn, L.; Cavallaro, S.; Celano, L.; de Filippo, E.; D'erasmo, G.; di Santo, D.; Fiore, E. M.; Fokin, A.; Geraci, M.; Giustolisi, F.; Kuznetsov, A.; Lanzanò, G.; Mahboub, D.; Marrone, S.; Merchez, F.; Mårtensson, J.; Palazzolo, F.; Palomba, M.; Pantaleo, A.; Paticchio, V.; Riera, G.; Sperduto, M. L.; Sutera, C.; Tagliente, G.; Urrata, M.; Westerberg, L.

    2001-07-01

    The strength of the neutron-neutron correlation function from the E=45A MeV 58Ni+27Al, natNi, and 197Au reactions depends on the neutron parallel velocity. This indicates the presence of multiple sources of neutron emission. We find these sources consistent with a dissipative, binary reaction mechanism as it is described by, e.g., Boltzmann-Uehling-Uhlenbeck calculations.

  10. Standardisation of water-moderated 241Am-Be neutron source using De Pangher neutron long counter: experimental and Monte Carlo modelling.

    PubMed

    Ghodke, Shobha; Kumari, Sujatha; Singh, Yashoda; Sathian, V; Mahant, A K; Sharma, D N

    2012-02-01

    A convenient neutron source is made for calibration of neutron survey instruments and personal dosimeters that are used in various nuclear installations such as fuel reprocessing, waste management, fuel fabrication and oil and well logging facilities, etc. This source consists of a bare (241)Am-Be neutron source placed at the centre of a 15-cm radius stainless steel spherical shell filled with distilled water. This paper describes the standardisation of the source at Bhabha Atomic Research Centre, using De Pangher neutron long counter both experimentally and using the Monte Carlo simulation. The ratio of neutron yield of water moderated to the bare (241)Am-Be neutron source was found to be 0.573. From the simulation, the neutron-fluence-weighted average energy of water-moderated (241)Am-Be source (fluence-weighted average energy of 2.25 MeV, dose-weighted average energy of 3.55 MeV) was found to be nearly the same as that of a (252)Cf source (fluence-weighted average energy of 2.1 MeV, dose-weighted average energy of 2.3 MeV). This source can be used for calibration in addition to (252)Cf, to study the variation in response of neutron monitoring instruments. PMID:21498862

  11. A Targeted Search for Point Sources of EeV Neutrons

    E-print Network

    Aab, A; Aglietta, M; Ahlers, M; Ahn, E J; Samarai, I Al; Albuquerque, I F M; Allekotte, I; Allen, J; Allison, P; Almela, A; Castillo, J Alvarez; Alvarez-Muñiz, J; Batista, R Alves; Ambrosio, M; Aminaei, A; Anchordoqui, L; Andringa, S; Aramo, C; Arqueros, F; Asorey, H; Assis, P; Aublin, J; Ave, M; Avenier, M; Avila, G; Badescu, A M; Barber, K B; Bäuml, J; Baus, C; Beatty, J J; Becker, K H; Bellido, J A; Berat, C; Bertou, X; Biermann, P L; Billoir, P; Blanco, F; Blanco, M; Bleve, C; Blümer, H; Bohá?ová, M; Boncioli, D; Bonifazi, C; Bonino, R; Borodai, N; Brack, J; Brancus, I; Brogueira, P; Brown, W C; Buchholz, P; Bueno, A; Buscemi, M; Caballero-Mora, K S; Caccianiga, B; Caccianiga, L; Candusso, M; Caramete, L; Caruso, R; Castellina, A; Cataldi, G; Cazon, L; Cester, R; Chavez, A G; Cheng, S H; Chiavassa, A; Chinellato, J A; Chudoba, J; Cilmo, M; Clay, R W; Cocciolo, G; Colalillo, R; Collica, L; Coluccia, M R; Conceição, R; Contreras, F; Cooper, M J; Coutu, S; Covault, C E; Criss, A; Cronin, J; Curutiu, A; Dallier, R; Daniel, B; Dasso, S; Daumiller, K; Dawson, B R; de Almeida, R M; De Domenico, M; de Jong, S J; Neto, J R T de Mello; De Mitri, I; de Oliveira, J; de Souza, V; del Peral, L; Deligny, O; Dembinski, H; Dhital, N; Di Giulio, C; Di Matteo, A; Diaz, J C; Castro, M L Díaz; Diep, P N; Diogo, F; Dobrigkeit, C; Docters, W; D'Olivo, J C; Dong, P N; Dorofeev, A; Dova, M T; Ebr, J; Engel, R; Erdmann, M; Erfani, M; Escobar, C O; Espadanal, J; Etchegoyen, A; Luis, P Facal San; Falcke, H; Fang, K; Farrar, G; Fauth, A C; Fazzini, N; Ferguson, A P; Fernandes, M; Fick, B; Figueira, J M; Filevich, A; Filip?i?, A; Fox, B D; Fratu, O; Fröhlich, U; Fuchs, B; Fuji, T; Gaior, R; García, B; Roca, S T Garcia; Garcia-Gamez, D; Garcia-Pinto, D; Garilli, G; Bravo, A Gascon; Gate, F; Gemmeke, H; Ghia, P L; Giaccari, U; Giammarchi, M; Giller, M; Glaser, C; Glass, H; Albarracin, F Gomez; Berisso, M Gómez; Vitale, P F Gómez; Gonçalves, P; Gonzalez, J G; Gookin, B; Gorgi, A; Gorham, P; Gouffon, P; Grebe, S; Griffith, N; Grillo, A F; Grubb, T D; Guardincerri, Y; Guarino, F; Guedes, G P; Hansen, P; Harari, D; Harrison, T A; Harton, J L; Hasankiadeh, Q D; Haungs, A; Hebbeker, T; Heck, D; Heimann, P; Herve, A E; Hill, G C; Hojvat, C; Hollon, N; Holt, E; Homola, P; Hörandel, J R; Horvath, P; Hrabovský, M; Huber, D; Huege, T; Insolia, A; Isar, P G; Islo, K; Jandt, I; Jansen, S; Jarne, C; Josebachuili, M; Kääpä, A; Kambeitz, O; Kampert, K H; Kasper, P; Katkov, I; Kégl, B; Keilhauer, B; Keivani, A; Kemp, E; Kieckhafer, R M; Klages, H O; Kleifges, M; Kleinfeller, J; Krause, R; Krohm, N; Krömer, O; Kruppke-Hansen, D; Kuempel, D; Kunka, N; La Rosa, G; LaHurd, D; Latronico, L; Lauer, R; Lauscher, M; Lautridou, P; Coz, S Le; Leão, M S A B; Lebrun, D; Lebrun, P; de Oliveira, M A Leigui; Letessier-Selvon, A; Lhenry-Yvon, I; Link, K; López, R; Agüera, A Lopez; Louedec, K; Bahilo, J Lozano; Lu, L; Lucero, A; Ludwig, M; Lyberis, H; Maccarone, M C; Malacari, M; Maldera, S; Maller, J; Mandat, D; Mantsch, P; Mariazzi, A G; Marin, V; Mari?, I C; Marsella, G; Martello, D; Martin, L; Martinez, H; Bravo, O Martínez; Martraire, D; Meza, J J Masías; Mathes, H J; Mathys, S; Matthews, A J; Matthews, J; Matthiae, G; Maurel, D; Maurizio, D; Mayotte, E; Mazur, P O; Medina, C; Medina-Tanco, G; Melissas, M; Melo, D; Menichetti, E; Menshikov, A; Messina, S; Meyhandan, R; Mi?anovi?, S; Micheletti, M I; Middendorf, L; Minaya, I A; Miramonti, L; Mitrica, B; Molina-Bueno, L; Mollerach, S; Monasor, M; Ragaigne, D Monnier; Montanet, F; Morello, C; Moreno, J C; Mostafá, M; Moura, C A; Muller, M A; Müller, G; Münchmeyer, M; Mussa, R; Navarra, G; Navas, S; Necesal, P; Nellen, L; Nelles, A; Neuser, J; Niechciol, M; Niemietz, L; Niggemann, T; Nitz, D; Nosek, D; Novotny, V; Nožka, L; Ochilo, L; Olinto, A; Oliveira, M; Ortiz, M; Pacheco, N; Selmi-Dei, D Pakk; Palatka, M; Pallotta, J; Palmieri, N; Papenbreer, P; Parente, G; Parra, A; Pastor, S; Paul, T; Pech, M; P?kala, J; Pelayo, R; Pepe, I M; Perrone, L; Pesce, R; Petermann, E; Peters, C; Petrera, S; Petrolini, A; Petrov, Y; Piegaia, R; Pierog, T; Pieroni, P; Pimenta, M; Pirronello, V; Platino, M; Plum, M; Porcelli, A; Porowski, C; Privitera, P; Prouza, M; Purrello, V; Quel, E J; Querchfeld, S; Quinn, S; Rautenberg, J; Ravel, O; Ravignani, D; Revenu, B; Ridky, J; Riggi, S; Risse, M; Ristori, P; Rizi, V; Roberts, J; de Carvalho, W Rodrigues; Cabo, I Rodriguez; Fernandez, G Rodriguez; Rojo, J Rodriguez; Rodríguez-Frías, M D; Ros, G; Rosado, J; Rossler, T; Roth, M; Roulet, E; Rovero, A C; Rühle, C; Saffi, S J; Saftoiu, A; Salamida, F; Salazar, H; Greus, F Salesa; Salina, G; Sánchez, F; Sanchez-Lucas, P; Santo, C E; Santos, E; Santos, E M; Sarazin, F; Sarkar, B; Sarmento, R; Sato, R; Scharf, N; Scherini, V; Schieler, H; Schiffer, P; Schmidt, A

    2014-01-01

    A flux of neutrons from an astrophysical source in the Galaxy can be detected in the Pierre Auger Observatory as an excess of cosmic-ray air showers arriving from the direction of the source. To avoid the statistical penalty for making many trials, classes of objects are tested in combinations as nine "target sets", in addition to the search for a neutron flux from the Galactic Center or from the Galactic Plane. Within a target set, each candidate source is weighted in proportion to its electromagnetic flux, its exposure to the Auger Observatory, and its flux attenuation factor due to neutron decay. These searches do not find evidence for a neutron flux from any class of candidate sources. Tabulated results give the combined p-value for each class, with and without the weights, and also the flux upper limit for the most significant candidate source within each class. These limits on fluxes of neutrons significantly constrain models of EeV proton emission from non-transient discrete sources in the Galaxy.

  12. A TARGETED SEARCH FOR POINT SOURCES OF EeV NEUTRONS

    SciTech Connect

    Aab, A.; Abreu, P.; Andringa, S.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Al Samarai, I.; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Castillo, J. Alvarez; Alvarez-Muñiz, J.; Batista, R. Alves; Ambrosio, M.; Aramo, C.; Aminaei, A.; Anchordoqui, L.; Arqueros, F.; Collaboration: Pierre Auger Collaboration101; and others

    2014-07-10

    A flux of neutrons from an astrophysical source in the Galaxy can be detected in the Pierre Auger Observatory as an excess of cosmic-ray air showers arriving from the direction of the source. To avoid the statistical penalty for making many trials, classes of objects are tested in combinations as nine ''target sets'', in addition to the search for a neutron flux from the Galactic center or from the Galactic plane. Within a target set, each candidate source is weighted in proportion to its electromagnetic flux, its exposure to the Auger Observatory, and its flux attenuation factor due to neutron decay. These searches do not find evidence for a neutron flux from any class of candidate sources. Tabulated results give the combined p-value for each class, with and without the weights, and also the flux upper limit for the most significant candidate source within each class. These limits on fluxes of neutrons significantly constrain models of EeV proton emission from non-transient discrete sources in the Galaxy.

  13. Modified big bang nucleosynthesis with non-standard neutron sources

    E-print Network

    Alain Coc; Maxim Pospelov; Jean-Philippe Uzan; Elisabeth Vangioni

    2014-05-07

    During big bang nucleosynthesis, any injection of extra neutrons around the time of the $^7$Be formation, i.e. at a temperature of order $T \\simeq 50$~keV, can reduce the predicted freeze-out amount of $^7$Be + $^7$Li that otherwise remains in sharp contradiction with the Spite plateau value inferred from the observations of Pop II stars. However, the growing confidence in the primordial D/H determinations puts a strong constraint on any such scenario. We address this issue in detail, analyzing different temporal patterns of neutron injection, such as decay, annihilation, resonant annihilation, and oscillation between mirror and standard model world neutrons. For this latter case, we derive the realistic injection pattern taking into account thermal effects (damping and refraction) in the primordial plasma. If the extra neutron supply is the sole non-standard mechanism operating during the BBN, the suppression of lithium abundance below Li/H~$\\leq 1.9 \\times 10^{-10}$ always leads to the overproduction of deuterium, D/H~$\\geq 3.6 \\times 10^{-5}$, well outside the error bars suggested by recent observations.

  14. Consideration of a ultracold neutron source in two-dimensional cylindrical geometry by taking simulated boundaries

    SciTech Connect

    Gheisari, R.; Firoozabadi, M. M.; Mohammadi, H.

    2014-01-15

    A new idea to calculate ultracold neutron (UCN) production by using Monte Carlo simulation method to calculate the cold neutron (CN) flux and an analytical approach to calculate the UCN production from the simulated CN flux was given. A super-thermal source (UCN source) was modeled based on an arrangement of D{sub 2}O and solid D{sub 2} (sD{sub 2}). The D{sub 2}O was investigated as the neutron moderator, and sD{sub 2} as the converter. In order to determine the required parameters, a two-dimensional (2D) neutron balance equation written in Matlab was combined with the MCNPX simulation code. The 2D neutron-transport equation in cylindrical (? ? z) geometry was considered for 330 neutron energy groups in the sD{sub 2}. The 2D balance equation for UCN and CN was solved using simulated CN flux as boundary value. The UCN source dimensions were calculated for the development of the next UCN source. In the optimal condition, the UCN flux and the UCN production rate (averaged over the sD{sub 2} volume) equal to 6.79?×?10{sup 6} cm{sup ?2}s{sup ?1} and 2.20 ×10{sup 5} cm{sup ?3}s{sup ?1}, respectively.

  15. Comparison of LaBr3:Ce and NaI(Tl) Scintillators for Radio-Isotope Identification Devices

    SciTech Connect

    Milbrath, Brian D.; Choate, Bethany J.; Fast, Jim E.; Hensley, Walter K.; Kouzes, Richard T.; Schweppe, John E.

    2007-03-11

    Lanthanum bromide (LaBr3:Ce) scintillators offer significantly better resolution [<3 percent at 662 kilo-electron volt (keV)] relative to sodium iodide [NaI(Tl)] but contain internal radioactivity that contributes to spectral counts. LaBr3:Ce has recently become available commercially in sizes large enough for the hand-held radio-isotope identification device (RIID) market. To study its potential for RIIDs, a series of measurements were performed comparing a 1.5 ´ 1.5 inch LaBr¬3:Ce detector with an Exploranium GR 135 RIID, which contains a 1.5 ´ 2.2 inch NaI(Tl) detector. Measurements were taken for short time frames and included examples of naturally occurring radioactive material (NORM), typically found in cargo, and special nuclear materials. To facilitate direct comparison, spectra from the different detectors were analyzed with the same isotope identification software (ORTEC ScintiVision?). In general, the LaBr3:Ce detector was able to find more peaks and find them faster than the NaI(Tl) detector. To the same level of significance, the LaBr3:Ce detector was usually two to three times faster. The notable exception was for 40K containing NORM where interfering internal activity due to 138La in the LaBr3:Ce detector exists and NaI(Tl) consistently outperformed LaBr3:Ce.

  16. Comparison of LaBr 3:Ce and NAI(Tl) scintillators for radio-isotope identification devices

    NASA Astrophysics Data System (ADS)

    Milbrath, B. D.; Choate, B. J.; Fast, J. E.; Hensley, W. K.; Kouzes, R. T.; Schweppe, J. E.

    2007-03-01

    Lanthanum bromide (LaBr 3:Ce) scintillators offer significantly better resolution (<3 percent at 662 keV) relative to sodium iodide (NaI(Tl)) but contain internal radioactivity that contributes to spectral counts. LaBr 3:Ce has recently become available commercially in sizes large enough for the hand-held radio-isotope identification device (RIID) market. To study its potential for RIIDs, a series of measurements were performed comparing a 1.5×1.5-in. LaBr 3:Ce detector with an Exploranium GR-135 RIID, which contains a 1.5×2.2-in. NaI(Tl) detector. Measurements were taken for short time frames and included examples of naturally occurring radioactive material (NORM), typically found in cargo, and special nuclear materials. To facilitate direct comparison, spectra from the different detectors were analyzed with the same isotope identification software (ORTEC ScintiVision™). In general, the LaBr 3:Ce detector was able to find more peaks and find them faster than the NaI(Tl) detector. To the same level of significance, the LaBr 3:Ce detector was usually two to three times faster. The notable exception was for 40K-containing NORM where interfering internal activity due to 138La in the LaBr 3:Ce detector exists and NaI(Tl) consistently outperformed LaBr 3:Ce.

  17. Comparison of LaBr3:Ce and NaI(Tl) Scintillators for Radio-Isotope Identification Devices

    SciTech Connect

    Milbrath, Brian D.; Choate, Bethany J.; Fast, Jim E.; Kouzes, Richard T.; Schweppe, John E.

    2005-10-23

    LaBr3:Ce scintillators offer significantly better resolution (< 3% at 662 keV) relative to NaI(Tl) and have recently become commercially available in sizes large enough for the handheld, Radio-Isotope Identification Device (RIID) market. Drawbacks to lanthanum halide detectors, however, include internal radioactivity contributing to spectral counts, and a low-energy response which can cause detector resolution to be worse than that of NaI(Tl) below 100 keV. To study the potential of this new material for RIIDs we performed a series of measurements comparing a 1.5² ´ 1.5² LaBr¬3:Ce detector with an Exploranium GR-135 RIID, which contains a 1.5² ´ 2.2² NaI(Tl) detector. Measurements were taken for short timeframes, as typifies RIID usage. Measurements included examples of naturally occurring radioactive material (NORM), typically found in cargo, and special nuclear materials. Some measurements were non-contact, involving short distances or cargo shielding scenarios. To facilitate direct comparison, spectra from the different detectors were analyzed with the same isotope-identification software (ORTEC ScintiVision).

  18. Using polycrystalline bismuth filter in an ultracold neutron source with superfluid helium

    NASA Astrophysics Data System (ADS)

    Serebrov, A. P.; Lyamkin, V. A.; Runov, V. V.; Ivanov, S. A.; Onegin, M. S.; Fomin, A. K.

    2015-10-01

    Placing polycrystalline bismuth filter in front of an ultracold neutron (UCN) source with superfluid helium at 1 K is shown to be effective. The use of this filter ensures a 30-fold decrease (down to 0.5 W) in the level of heat load in the UCN source, while reducing by 30% the flux of neutrons with 9-Å wavelength (which are converted into UCNs). The phenomenon of small-angle scattering on polycrystalline bismuth has been studied and shown to be insignificant. Cooling of the filter to liquid nitrogen temperature increases the transmission of 9-Å neutrons by only 8%; hence, creation of this cooling system is inexpedient. A project of a technological complex designed for the UCN source at the PIK reactor is presented, which ensures the removal of 1-W heat load from the UCN source with superfluid helium at a 1-K temperature level.

  19. Performance evaluation of the source description of the THOR BNCT epithermal neutron beam.

    PubMed

    Liu, Yuan-Hao; Tsai, Pi-En; Yu, Hui-Ting; Lin, Yi-Chun; Huang, Yu-Shiang; Huang, Chun-Kai; Liu, Yen-Wan Hsueh; Liu, Hong-Ming; Jiang, Shiang-Huei

    2011-12-01

    This paper aims to evaluate the performance of the source description of the THOR BNCT beam via different measurement techniques in different phantoms. The measurement included (1) the absolute reaction rate measurement of a set of triple activation foils, (2) the neutron and gamma-ray dose rates measured using the paired ionization chamber method, and (3) the relative reaction rate distributions obtained using the indirect neutron radiography. Three source descriptions, THOR-Y09, surface source file RSSA, and THOR-50C, were tested. The comparison results concluded that THOR-Y09 is a well-tested source description not only for neutron components, but also for gamma-ray component. PMID:21570855

  20. Evaluation of the characteristics of the neutron reference field using D2O-moderated 252Cf source.

    PubMed

    Kowatari, M; Fujii, K; Takahashi, M; Yoshizawa, M; Shimizu, S; Kawasaki, K; Yamaguchi, Y

    2007-01-01

    The ambient/personal dose equivalent per fluence for D(2)O moderated (252)Cf neutron source was determined by measurement. An appropriate subtraction of the scattered neutrons is required for the accurate measurement of direct neutrons. A cubic shadow object was used for the subtraction of the scattered neutrons from the surroundings. The scattered neutrons to be subtracted vary with the position of the shadow object due to the large volume of the source. Using the Monte Carlo code MCNP-4C, the optimum positions of the shadow object were surveyed for subtracting the scattered neutrons. The energy spectra of direct neutrons were measured in the optimum position. The dosimetric parameters for the D(2)O moderated (252)Cf neutron source were reasonable, taking into account the uncertainties of the parameters. PMID:17525058

  1. A strongly heated neutron star in the transient z source MAXI J0556-332

    SciTech Connect

    Homan, Jeroen; Remillard, Ronald A.; Fridriksson, Joel K.; Wijnands, Rudy; Cackett, Edward M.; Degenaar, Nathalie; Linares, Manuel

    2014-11-10

    We present Chandra, XMM-Newton, and Swift observations of the quiescent neutron star in the transient low-mass X-ray binary MAXI J0556-332. Observations of the source made during outburst (with the Rossi X-ray Timing Explorer) reveal tracks in its X-ray color-color and hardness-intensity diagrams that closely resemble those of the neutron-star Z sources, suggesting that MAXI J0556-332 had near- or super-Eddington luminosities for a large part of its ?16 month outburst. A comparison of these diagrams with those of other Z sources suggests a source distance of 46 ± 15 kpc. Fits to the quiescent spectra of MAXI J0556-332 with a neutron-star atmosphere model (with or without a power-law component) result in distance estimates of 45 ± 3 kpc, for a neutron-star radius of 10 km and a mass of 1.4 M {sub ?}. The spectra show the effective surface temperature of the neutron star decreasing monotonically over the first ?500 days of quiescence, except for two observations that were likely affected by enhanced low-level accretion. The temperatures we obtain for the fits that include a power law (kT{sub eff}{sup ?} = 184-308 eV) are much higher than those seen for any other neutron star heated by accretion, while the inferred cooling (e-folding) timescale (?200 days) is similar to other sources. Fits without a power law yield higher temperatures (kT{sub eff}{sup ?} = 190-336 eV) and a shorter e-folding time (?160 days). Our results suggest that the heating of the neutron-star crust in MAXI J0556-332 was considerably more efficient than for other systems, possibly indicating additional or more efficient shallow heat sources in its crust.

  2. Characterization of the graphite pile as a source of thermal neutrons

    NASA Astrophysics Data System (ADS)

    Vykydal, Zdenek; Králík, Miloslav; Jan?á?, Aleš; Kopecký, Zden?k; Dressler, Jan; Veškrna, Martin

    2015-11-01

    A new graphite pile designed to serve as a standard source of thermal neutrons has been built at the Czech Metrology Institute. Actual dimensions of the pile are 1.95 m (W)×1.95 m (L)×2.0 m (H). At its center, there is a measurement channel whose dimensions are 0.4 m×0.4 m×1.25 m (depth). The channel is equipped with a calibration bench, which allows reproducible placement of the tested/calibrated device. At a distance of 80 cm from the channel axis, six holes are symmetrically located allowing the placement of radionuclide neutron sources of Pu-Be and/or Am-Be type. Spatial distribution of thermal neutron fluence in the cavity was calculated in detail with the MCNP neutron transport code. Experimentally, it was measured with two active detectors: a small 3He proportional detector by the French company LMT, type 0.5 NH 1/1 KF, and a silicon pixel detector Timepix with 10B converter foil. The relative values of thermal neutron fluence rate obtained with active detectors were converted to absolute ones using thermal neutron fluence rates measured by means of gold foil activation. The quality of thermal neutron field was characterized by the cadmium ratio.

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

    NASA Astrophysics Data System (ADS)

    Korobkina, E.; Medlin, G.; Wehring, B.; Hawari, A. I.; Huffman, P. R.; Young, A. R.; Beaumont, B.; Palmquist, G.

    2014-12-01

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

  4. Calibration of Time Of Flight Detectors Using Laser-driven Neutron Source

    E-print Network

    S. R. Mirfayzi; S. Kar; H. Ahmed; A. G. Krygier; A. Green; A. Alejo; R. Clarke; R. R. Freeman; J. Fuchs; D. Jung; A. Kleinschmidt; J. T. Morrison; Z. Najmudin; H. Nakamura; P. Norreys; M. Oliver; M. Roth; L. Vassura; M. Zepf; M. Borghesi

    2015-06-15

    Calibration of three scintillators (EJ232Q, BC422Q and EJ410) in a time-of-flight (TOF) arrangement using a laser drive-neutron source is presented. The three plastic scintillator detectors were calibrated with gamma insensitive bubble detector spectrometers, which were absolutely calibrated over a wide range of neutron energies ranging from sub MeV to 20 MeV. A typical set of data obtained simultaneously by the detectors are shown, measuring the neutron spectrum emitted from a petawatt laser irradiated thin foil.

  5. Collinear Cluster Tripartition as a Neutron Source--Evaluation of the Setup Parameters

    SciTech Connect

    Kamanin, D. V.; Kuznetsova, E. A.; Aleksandrov, A. A.; Aleksandrova, I. A.; Borzakov, S. B.; Chelnokov, M. L.; Pham Minh, D.; Kondratyev, N. A.; Kopach, Yu. N.; Panteleev, Ts.; Penionzhkevich, Yu. E.; Svirikhin, A. I.; Sokol, E. A.; Testov, D. A.; Zhuchko, V. E.; Yeremin, A. V.; Pyatkov, Yu. V.; Jacobs, N.; Ryabov, Yu. V.

    2010-04-30

    Forthcoming experiments aimed at studying the mechanism of collinear cluster tripartition are planning to be performed with the new facility. Charged products will be registered with the double arm time-of-flight spectrometer composed of mosaics of PIN -diodes and MCP (micro channel plates) based timing detectors. Several tens of {sup 3}He-filled counters will be gathered round the {sup 252}Cf source. In order to choose an optimal configuration of the neutron detector and other parameters of the experiment special modeling has performed using both 'neutron barrel' and known MCNP code. The first test run of the new facility is in progress also its 'neutron skin' in under construction.

  6. Design and simulation of an optimized e-linac based neutron source for BNCT research.

    PubMed

    Durisi, E; Alikaniotis, K; Borla, O; Bragato, F; Costa, M; Giannini, G; Monti, V; Visca, L; Vivaldo, G; Zanini, A

    2015-12-01

    The paper is focused on the study of a novel photo-neutron source for BNCT preclinical research based on medical electron Linacs. Previous studies by the authors already demonstrated the possibility to obtain a mixed thermal and epithermal neutron flux of the order of 10(7)cm(-2)s(-1). This paper investigates possible Linac's modifications and a new photo-converter design to rise the neutron flux above 5 10(7)cm(-2)s(-1), also reducing the gamma contamination. PMID:26315098

  7. Proceedings of the workshop on ion source issues relevant to a pulsed spallation neutron source: Part 2 workshop presentations

    SciTech Connect

    Schroeder, L.; Leung, Ka-Ngo; Alonso, J.

    1994-10-01

    As part of the Lawrence Berkeley Laboratory Pulsed Spallation Source study, this Workshop was convened to address ion-source technology`s present status with respect to the next-generation Pulsed Spallation Source in the 1-5 MW range for the neutron scattering community. Considerations of Low Energy Beam Transport (LEBT) parameters and designs were included in the discussions throughout the Workshop. Ion-source requirements and actually-achieved performances were assessed, resulting in a determination of research and development requirements to bridge the gap. Part 1 of these Proceedings summarizes the Workshop; Part 2 contains viewgraphs of Workshop presentations.

  8. Secondary Startup Neutron Sources as a Source of Tritium in a Pressurized Water Reactor (PWR) Reactor Coolant System (RCS)

    SciTech Connect

    Shaver, Mark W.; Lanning, Donald D.

    2010-02-01

    The hypothesis of this paper is that the Zircaloy clad fuel source is minimal and that secondary startup neutron sources are the significant contributors of the tritium in the RCS that was previously assigned to release from fuel. Currently there are large uncertainties in the attribution of tritium in a Pressurized Water Reactor (PWR) Reactor Coolant System (RCS). The measured amount of tritium in the coolant cannot be separated out empirically into its individual sources. Therefore, to quantify individual contributors, all sources of tritium in the RCS of a PWR must be understood theoretically and verified by the sum of the individual components equaling the measured values.

  9. Compact D-D Neutron Source-Driven Subcritical Multiplier and Beam-Shaping Assembly for Boron Neutron Capture Therapy

    SciTech Connect

    Francesco Ganda; Jasmina Vujic; Ehud Greenspan; Ka-Ngo Leung

    2010-12-01

    This work assesses the feasibility of using a small, safe, and inexpensive keff 0.98 subcritical fission assembly [subcritical neutron multiplier (SCM)] to amplify the treatment neutron beam intensity attainable from a compact deuterium-deuterium (D-D) fusion neutron source delivering [approximately]1012 n/s. The objective is to reduce the treatment time for deep-seated brain tumors to [approximately]1 h. The paper describes the optimal SCM design and two optimal beam-shaping assemblies (BSAs) - one designed to maximize the dose rate and the other designed to maximize the total dose that can be delivered to a deep-seated tumor. The neutron beam intensity amplification achieved with the optimized SCM and BSA results in an increase in the treatment dose rate by a factor of 18: from 0.56 Gy/h without the SCM to 10.1 Gy/h. The entire SCM is encased in an aluminum structure. The total amount of 20% enriched uranium required for the SCM is 8.5 kg, and the cost (not including fabrication) is estimated to be less than $60,000. The SCM power level is estimated at 400 W when driven by a 1012 n/s D-D neutron source. This translates into consumption of only [approximately]0.6% of the initially loaded 235U atoms during 50 years of continuous operation and implies that the SCM could operate continuously for the entire lifetime of the facility without refueling. Cooling the SCM does not pose a challenge; it may be accomplished by natural circulation as the maximum heat flux is only 0.034 W/cm2.

  10. Viability of the ESS-Bilbao neutron source for irradiation of nuclear fusion materials

    NASA Astrophysics Data System (ADS)

    Páramo, A. R.; Sordo, F.; Perlado, J. M.; Rivera, A.

    2014-01-01

    The ESS-Bilbao neutron source, currently under construction, is conceived as a multipurpose facility. It will offer a fast neutron beam line for materials irradiation. In this paper we discuss the viability of ESS-Bilbao for experimental studies of fusion materials. Making use of the already designed target station we have calculated the neutron spectrum expected in the fast neutron line. Then, we have studied the neutron irradiation effects in two model materials: iron and silica. We have calculated the expected PKA (primary knock-on atom) spectra and light species production as well as the damage production in these materials. Regarding structural materials, we conclude that the ESS-Bilbao neutron irradiation facility will play a minor role due to the resulting low neutron fluxes (about two orders of magnitude lower than in fusion reactors). On the other hand, ESS-Bilbao turns out to be relevant for studies of final lenses in laser fusion power plants. A comparison with the conditions expected for HiPER final lenses shows that the fluxes will be only a factor 5 smaller in ESS-Bilbao and the PKA spectra will be very similar. Taking into account, in addition, that relevant effects on lenses occur from the onset of irradiation, we conclude that an appropriate irradiation cell with in situ characterisation techniques will make ESS-Bilbao very attractive for applied neutron damage studies of laser fusion final lenses. Finally, we compare ESS-Bilbao with other facilities.

  11. Gamma-ray measurements at the WNR white neutron source

    SciTech Connect

    Nelson, R.O.; Wender, S.A.; Mayo, D.R.

    1994-12-31

    Photon production data have been acquired in the incident neutron energy range, 1 < E{sub n} < 400 MeV, for a number of target nuclei, gamma-ray energy ranges, and reactions, using the continuous-energy neutron beam of the WNR facility at Los Alamos. Gamma-ray production measurements using high resolution Ge detectors have been employed for gamma-rays in the energy range, 0.1 < E{sub {gamma}} < 10 MeV. These measurements allow identification of reactions from the known energies of the gamma-ray transitions between low-lying states in the final nucleus. Some of the targets studied include: N, O, Al, Na, {sup 56}Fe, and {sup 207,208}Pb. These data are useful both for testing nuclear reaction models at intermediate energies and for numerous applied purposes. BGO detectors do not have the good energy resolution of Ge detectors, but have much greater detection efficiency for gamma rays with energies greater than a few MeV. We have used an array of 5 BGO detectors to measure cross sections and angular distributions for photon production from C and N. A large, well-shielded BGO detector has been used to measure fast neutron capture in the giant resonance region with a maximum gamma-ray energy of 52 MeV. We present results of our study of the isovector giant quadrupole resonance in {sup 41}Ca via these capture measurements. Recent measurements of inclusive photon spectra from our neutron proton Bremsstrahlung experiment have been made using a gamma-ray telescope to detect gamma-rays in the energy range, 40 < E{sub {gamma}} < 300 MeV. This detector is briefly described. The advantages and disadvantages of these detector systems are discussed using examples from our measurements. The status of current measurements is presented.

  12. HYSPEC : A CRYSTAL TIME OF FLIGHT HYBRID SPECTROMETER FOR THE SPALLATION NEUTRON SOURCE.

    SciTech Connect

    SHAPIRO,S.M.; ZALIZNYAK,I.A.

    2002-12-30

    This document lays out a proposal by the Instrument Development Team (IDT) composed of scientists from leading Universities and National Laboratories to design and build a conceptually new high-flux inelastic neutron spectrometer at the pulsed Spallation Neutron Source (SNS) at Oak Ridge. This instrument is intended to supply users of the SNS and scientific community, of which the IDT is an integral part, with a platform for ground-breaking investigations of the low-energy atomic-scale dynamical properties of crystalline solids. It is also planned that the proposed instrument will be equipped with a polarization analysis capability, therefore becoming the first polarized beam inelastic spectrometer in the SNS instrument suite, and the first successful polarized beam inelastic instrument at a pulsed spallation source worldwide. The proposed instrument is designed primarily for inelastic and elastic neutron spectroscopy of single crystals. In fact, the most informative neutron scattering studies of the dynamical properties of solids nearly always require single crystal samples, and they are almost invariably flux-limited. In addition, in measurements with polarization analysis the available flux is reduced through selection of the particular neutron polarization, which puts even more stringent limits on the feasibility of a particular experiment. To date, these investigations have mostly been carried out on crystal spectrometers at high-flux reactors, which usually employ focusing Bragg optics to concentrate the neutron beam on a typically small sample. Construction at Oak Ridge of the high-luminosity spallation neutron source, which will provide intense pulsed neutron beams with time-averaged fluxes equal to those at medium-flux reactors, opens entirely new opportunities for single crystal neutron spectroscopy. Drawing upon experience acquired during decades of studies with both crystal and time-of-flight (TOF) spectrometers, the IDT has developed a conceptual design for a focused-beam, hybrid time-of-flight instrument with a crystal monochromator for the SNS called HYSPEC (an acronym for hybrid spectrometer). The proposed instrument has a potential to collect data more than an order of magnitude faster than existing steady-source spectrometers over a wide range of energy transfer ({h_bar}{omega}) and momentum transfer (Q) space, and will transform the way that data in elastic and inelastic single-crystal spectroscopy are collected. HYSPEC is optimized to provide the highest neutron flux on sample in the thermal and epithermal neutron energy ranges at a good-to-moderate energy resolution. By providing a flux on sample several times higher than other inelastic instruments currently planned for the SNS, the proposed instrument will indeed allow unique ground-breaking measurements, and will ultimately make polarized beam studies at a pulsed spallation source a realistic possibility.

  13. Advanced concept proof-of-principle demonstration: Switchable radioactive neutron source

    SciTech Connect

    Rhodes, E.A.; Bowers, D.L.; Boyar, R.E.; Dickerman, C.E.

    1995-10-01

    An advanced concept proof-of-principle demonstration was successfully performed to show the feasibility of a practical switchable radioactive neutron source (SRNS) that can be switched on and off like an accelerator, but without requiring accelerator equipment such as high voltage supply, control unit, etc. This source concept would provide a highly portable neutron source for field radiation measurement applications. Such a source would require minimal, if any, shielding when not in use. The SRNS, previously patented by Argonne staff, provides a means of constructing the alpha-emitting and light-element components of a radioactive neutron source, in such a fashion that these two components can brought together to turn the source ``on`` and then be separated to turn the source ``off``. An SRNS could be used for such field applications as active neutron interrogation of objects to detect fissile materials or to measure their concentration; and to excite gamma-ray emission for detection of specific elements that indicate toxic chemicals, drugs, explosives, etc. The demonstration was performed using Pu-238 as the alpha emitter and Be as the light element, in an air-atmosphere glovebox having no atmosphere purification capability. A stable, thin film of Pu-238 oxide was deposited on a stainless steel planchet. The ``on`` output of the demonstration Pu-238 film was measured to be 2.5 {times} 10{sup 6} neutrons/sec-gram of Pu-238. The measured ``off`` neutron rate was satisfactory, only about 5% of the ``on`` output, after two weeks of exposure to the glovebox atmosphere. After several weeks additional exposure, the ``off`` rate had increased to about 15%. This work demonstrates the feasibility of constructing practical, highly portable SRNS units with very low gamma-ray dose in the ``off`` position.

  14. Investigation of the neutron spectrum of americium-beryllium sources by Bonner sphere spectrometry

    NASA Astrophysics Data System (ADS)

    Bedogni, R.; Domingo, C.; Roberts, N.; Thomas, D. J.; Chiti, M.; Esposito, A.; Garcia, M. J.; Gentile, A.; Liu, Z. Z.; de-San-Pedro, M.

    2014-11-01

    Americium-beryllium neutron sources are certainly the most widely used in neutron dosimetry laboratories, basically due to their long half-life and their energy distribution, which covers the energy domain of interest for many applications in ambient and personal dosimetry. Nevertheless, the spectrum of this source depends on the materials and dimension of the capsule and on the amount and physical-chemical properties of the active material, thus affecting relevant quantities such as the spectrum-averaged fluence-to-dose equivalent conversion coefficient. A EURAMET (European Association of National Metrology Institutes) project (n. 1104) was initiated to experimentally investigate how the neutron spectrum changes for different source sizes and encapsulations with a view to providing improved data for a planned revision of the ISO 8529 Standard Series. The experimental campaign was carried out in the low scatter facility at NPL. Here three different Bonner sphere spectrometers, BSSs, were exposed to the neutron fields produced by three different neutron sources formats: one X3 capsule (1 Ci) and two X14 capsules (10 Ci and 15 Ci). The specific advantage of the BSS is the large sensitivity to low-energy neutrons (E<0.1 MeV) which is the component expected to be most affected by the capsule-to-capsule variations and the component which is least well known. This paper summarises the results of the campaign with emphasis on (1) estimating the low-energy component of the Am-Be neutron spectrum, according to the encapsulation type; (2) evaluating the coherence between the Bonner spheres data and the previous studies performed with high-resolution spectrometers but limited in energy to E>0.1 MeV; (3) understanding whether the ISO-recommended Am-Be spectrum needs to be amended, and for which source formats.

  15. Low-level measuring techniques for neutrons: High accuracy neutron source strength determination and fluence rate measurement at an underground laboratory

    NASA Astrophysics Data System (ADS)

    Zimbal, Andreas; Degering, Detlev; Reginatto, Marcel; Schuhmacher, Helmut; Wiegel, Burkhard; Zuber, Kai

    2013-08-01

    We report on measuring techniques for neutrons that have been developed at the Physikalisch-Technische Bundesanstalt (PTB), the German National Metrology Institute. PTB has characterized radioactive sources used in the BOREXINO and XENON100 experiments. For the BOREXINO experiment, a 228Th gamma radiation source was required which would not emit more than 10 neutrons per second. The determination of the neutron emission rate of this specially designed 228Th source was challenging due to the low neutron emission rate and because the ratio of neutron to gamma radiation was expected to be extremely low, of the order of 10-6. For the XENON100 detector, PTB carried out a high accuracy measurement of the neutron emission rate of an AmBe source. PTB has also done measurements in underground laboratories. A two month measurement campaign with a set of 3He-filled proportional counters was carried out in PTB's former UDO underground laboratory at the Asse salt mine. The aim of the campaign was to determine the intrinsic background of detectors, which is needed for the analysis of data taken in lowintensity neutron fields. At a later time, PTB did a preliminary measurement of the neutron fluence rate at the underground laboratory Felsenkeller operated by VKTA. By taking into account data from UDO, Felsenkeller, and detector calibrations made at the PTB facility, it was possible to estimate the neutron fluence rate at the Felsenkeller underground laboratory.

  16. SOURCES 4A: A Code for Calculating (alpha,n), Spontaneous Fission, and Delayed Neutron Sources and Spectra

    SciTech Connect

    Madland, D.G.; Arthur, E.D.; Estes, G.P.; Stewart, J.E.; Bozoian, M.; Perry, R.T.; Parish, T.A.; Brown, T.H.; England, T.R.; Wilson, W.B.; Charlton, W.S.

    1999-09-01

    SOURCES 4A is a computer code that determines neutron production rates and spectra from ({alpha},n) reactions, spontaneous fission, and delayed neutron emission due to the decay of radionuclides. The code is capable of calculating ({alpha},n) source rates and spectra in four types of problems: homogeneous media (i.e., a mixture of {alpha}-emitting source material and low-Z target material), two-region interface problems (i.e., a slab of {alpha}-emitting source material in contact with a slab of low-Z target material), three-region interface problems (i.e., a thin slab of low-Z target material sandwiched between {alpha}-emitting source material and low-Z target material), and ({alpha},n) reactions induced by a monoenergetic beam of {alpha}-particles incident on a slab of target material. Spontaneous fission spectra are calculated with evaluated half-life, spontaneous fission branching, and Watt spectrum parameters for 43 actinides. The ({alpha},n) spectra are calculated using an assumed isotropic angular distribution in the center-of-mass system with a library of 89 nuclide decay {alpha}-particle spectra, 24 sets of measured and/or evaluated ({alpha},n) cross sections and product nuclide level branching fractions, and functional {alpha}-particle stopping cross sections for Z < 106. The delayed neutron spectra are taken from an evaluated library of 105 precursors. The code outputs the magnitude and spectra of the resultant neutron source. It also provides an analysis of the contributions to that source by each nuclide in the problem.

  17. Monte Carlo modeling and analyses of YALINA- booster subcritical assembly Part II : pulsed neutron source.

    SciTech Connect

    Talamo, A.; Gohar, M. Y. A.; Rabiti, C.; Nuclear Engineering Division

    2008-10-22

    One of the most reliable experimental methods for measuring the kinetic parameters of a subcritical assembly is the Sjoestrand method applied to the reaction rate generated from a pulsed neutron source. This study developed a new analytical methodology for characterizing the kinetic parameters of a subcritical assembly using the Sjoestrand method, which allows comparing the analytical and experimental time dependent reaction rates and the reactivity measurements. In this methodology, the reaction rate, detector response, is calculated due to a single neutron pulse using MCNP/MCNPX computer code or any other neutron transport code that explicitly simulates the fission delayed neutrons. The calculation simulates a single neutron pulse over a long time period until the delayed neutron contribution to the reaction is vanished. The obtained reaction rate is superimposed to itself, with respect to the time, to simulate the repeated pulse operation until the asymptotic level of the reaction rate, set by the delayed neutrons, is achieved. The superimposition of the pulse to itself was calculated by a simple C computer program. A parallel version of the C program is used due to the large amount of data being processed, e.g. by the Message Passing Interface (MPI). The new calculation methodology has shown an excellent agreement with the experimental results available from the YALINA-Booster facility of Belarus. The facility has been driven by a Deuterium-Deuterium or Deuterium-Tritium pulsed neutron source and the (n,p) reaction rate has been experimentally measured by a {sup 3}He detector. The MCNP calculation has utilized the weight window and delayed neutron biasing variance reduction techniques since the detector volume is small compared to the assembly volume. Finally, this methodology was used to calculate the IAEA benchmark of the YALINA-Booster experiment.

  18. Plans for a Collaboratively Developed Distributed Control System for the Spallation Neutron Source

    SciTech Connect

    DeVan, W.R.; Gurd, D.P.; Hammonds, J.; Lewis, S.A.; Smith, J.D.

    1999-03-29

    The Spallation Neutron Source (SNS) is an accelerator-based pulsed neutron source to be built in Oak Ridge, Tennessee. The facility has five major sections - a ''front end'' consisting of a 65 keV H{sup -} ion source followed by a 2.5 MeV RFQ; a 1 GeV linac; a storage ring; a 1MW spallation neutron target (upgradeable to 2 MW); the conventional facilities to support these machines and a suite of neutron scattering instruments to exploit them. These components will be designed and implemented by five collaborating institutions: Lawrence Berkeley National Laboratory (Front End), Los Alamos National Laboratory (Linac); Brookhaven National Laboratory (Storage Ring); Argonne National Laboratory (Instruments); and Oak Ridge National Laboratory (Neutron Source and Conventional Facilities). It is proposed to implement a fully integrated control system for all aspects of this complex. The system will be developed collaboratively, with some degree of local autonomy for distributed systems, but centralized accountability. Technical integration will be based upon the widely-used EPICS control system toolkit, and a complete set of hardware and software standards. The scope of the integrated control system includes site-wide timing and synchronization, networking and machine protection. This paper discusses the technical and organizational issues of planning a large control system to be developed collaboratively at five different institutions, the approaches being taken to address those issues, as well as some of the particular technical challenges for the SNS control system.

  19. Calculated shielding characteristics of eight materials for neutrons and secondary photons produced by monoenergetic source neutrons with energies less than 400 MeV

    SciTech Connect

    Nakanishi, Noriyoshi; Shikata, Takashi; Fujita, Shin; Kosako, Toshiso

    1995-10-01

    Shielding characteristics of iron, lead, ordinary concrete, heavy concrete, graphite, marble, water, and paraffin were calculated for monoenergetic source neutrons with energies < 400 MeV. The depth dependence of neutron and secondary photon transmitted dose equivalents at the exit surfaces of shields of varying thickness is exhibited for some monoenergetic source neutrons and for each material. Their shielding characteristics are compared and discussed in terms of the degradation process of neutron energy and the change of neutron spectrum in typical shielding materials. Calculations were carried out by using the one-dimensional discrete ordinates code ANISN-JR and the cross-section library DLC-87/HILO. Systematic knowledge concerning the shielding of neutrons with energies < 400 MeV was successfully obtained.

  20. Establishment of a simple neutron calibration field from a moderated 252Cf source . Part I. Design and calculation of the simple neutron calibration field

    NASA Astrophysics Data System (ADS)

    Hara, A.; Iwai, S.; Nakamura, T.

    1987-02-01

    This paper describes the development and standardization of simple neutron reference calibration fields. These fields have been arranged for calibration of neutron detectors particularly used for radiation control and environmental measurements, having four different neutron spectra formed by a 252Cf source with or without moderators of iron, carbon or polyethylene. These calibration fields are independent of room-scattered neutrons, since they use only direct neutron components which are obtained by subtracting the results with shadow blocks from the results without those. The absolute energy spectra and dose equivalents of direct neutrons and room-scattered neutrons, and the effect of a shadow shield have been calculated by the one-dimensional ANISN-W, two-dimensional DOT-3.5 discrete ordinates codes and the three-dimensional MORSE-CG Monte Carlo code, for these four fields.

  1. A time-of-flight backscattering spectrometer at the Spallation Neutron Source, BASIS

    SciTech Connect

    Mamontov, E.; Herwig, K. W.

    2011-08-15

    We describe the design and current performance of the backscattering silicon spectrometer (BASIS), a time-of-flight backscattering spectrometer built at the spallation neutron source (SNS) of the Oak Ridge National Laboratory (ORNL). BASIS is the first silicon-based backscattering spectrometer installed at a spallation neutron source. In addition to high intensity, it offers a high-energy resolution of about 3.5 {mu}eV and a large and variable energy transfer range. These ensure an excellent overlap with the dynamic ranges accessible at other inelastic spectrometers at the SNS.

  2. Measurement and calculation of the emission anisotropy of an X1 252Cf neutron source.

    PubMed

    Hawkes, N P; Freedman, R; Tagziria, H; Thomas, D J

    2007-01-01

    The authors have measured the emission anisotropy from a (252)Cf spontaneous fission neutron source in an X1 encapsulation. The measurements were made in a large low-scatter laboratory using a long counter, and data were taken at angles varying in 10 degrees steps from 0 degrees to 180 degrees relative to the cylindrical axis of the source. Corrections were made for room scatter, loss of neutrons due to air scatter and detector dead time. Calculations corresponding to these measurements were subsequently carried out using the two Monte Carlo codes MCNP and MCBEND, and the results are compared with the measurements and with each other. PMID:17496296

  3. Target station design for a 1 MW pulsed spallation neutron source

    SciTech Connect

    Russell, G.J.; Baker, G.D.; Brewton, R.J.

    1993-12-31

    Target stations are vital components of the 1 MW, next generation spallation neutron source proposed for LANSCE. By and large, target stations design determines the overall performance of the facility. Many traditional concepts will probably have to be rethought, and many new concepts will have to be put forward to meet the 1 MW challenge. This article gives a brief overview of the proposed neutron spallation source from the target station viewpoint, as well as the general philosophy adopted for the design of the LANSCE-II target stations. Some of the saliant concepts and features envisioned for LANSCE-II are briefly described.

  4. Awareness, Preference, Utilization, and Messaging Research for the Spallation Neutron Source and High Flux Isotope Reactor

    SciTech Connect

    Bryant, Rebecca; Kszos, Lynn A

    2011-03-01

    Oak Ridge National Laboratory (ORNL) offers the scientific community unique access to two types of world-class neutron sources at a single site - the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR). The 85-MW HFIR provides one of the highest steady-state neutron fluxes of any research reactor in the world, and the SNS is one of the world's most intense pulsed neutron beams. Management of these two resources is the responsibility of the Neutron Sciences Directorate (NScD). NScD commissioned this survey research to develop baseline information regarding awareness of and perceptions about neutron science. Specific areas of investigative interest include the following: (1) awareness levels among those in the scientific community about the two neutron sources that ORNL offers; (2) the level of understanding members of various scientific communities have regarding benefits that neutron scattering techniques offer; and (3) any perceptions that negatively impact utilization of the facilities. NScD leadership identified users of two light sources in North America - the Advanced Photon Source (APS) at Argonne National Laboratory and the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory - as key publics. Given the type of research in which these scientists engage, they would quite likely benefit from including the neutron techniques available at SNS and HFIR among their scientific investigation tools. The objective of the survey of users of APS, NSLS, SNS, and HFIR was to explore awareness of and perceptions regarding SNS and HFIR among those in selected scientific communities. Perceptions of SNS and FHIR will provide a foundation for strategic communication plan development and for developing key educational messages. The survey was conducted in two phases. The first phase included qualitative methods of (1) key stakeholder meetings; (2) online interviews with user administrators of APS and NSLS; and (3) one-on-one interviews and traditional and online focus groups with scientists. The latter include SNS, HFIR, and APS users as well as scientists at ORNL, some of whom had not yet used HFIR and/or SNS. These approaches informed development of the second phase, a quantitative online survey. The survey consisted of 16 questions and 7 demographic categorizations, 9 open-ended queries, and 153 pre-coded variables and took an average time of 18 minutes to complete. The survey was sent to 589 SNS/HFIR users, 1,819 NSLS users, and 2,587 APS users. A total of 899 individuals provided responses for this study: 240 from NSLS; 136 from SNS/HFIR; and 523 from APS. The overall response rate was 18%.

  5. SOURCES 4C : a code for calculating ([alpha],n), spontaneous fission, and delayed neutron sources and spectra.

    SciTech Connect

    Wilson, W. B.; Perry, R. T.; Shores, E. F.; Charlton, W. S.; Parish, Theodore A.; Estes, G. P.; Brown, T. H.; Arthur, Edward D. ,; Bozoian, Michael; England, T. R.; Madland, D. G.; Stewart, J. E.

    2002-01-01

    SOURCES 4C is a computer code that determines neutron production rates and spectra from ({alpha},n) reactions, spontaneous fission, and delayed neutron emission due to radionuclide decay. The code is capable of calculating ({alpha},n) source rates and spectra in four types of problems: homogeneous media (i.e., an intimate mixture of a-emitting source material and low-Z target material), two-region interface problems (i.e., a slab of {alpha}-emitting source material in contact with a slab of low-Z target material), three-region interface problems (i.e., a thin slab of low-Z target material sandwiched between {alpha}-emitting source material and low-Z target material), and ({alpha},n) reactions induced by a monoenergetic beam of {alpha}-particles incident on a slab of target material. Spontaneous fission spectra are calculated with evaluated half-life, spontaneous fission branching, and Watt spectrum parameters for 44 actinides. The ({alpha},n) spectra are calculated using an assumed isotropic angular distribution in the center-of-mass system with a library of 107 nuclide decay {alpha}-particle spectra, 24 sets of measured and/or evaluated ({alpha},n) cross sections and product nuclide level branching fractions, and functional {alpha}-particle stopping cross sections for Z < 106. The delayed neutron spectra are taken from an evaluated library of 105 precursors. The code provides the magnitude and spectra, if desired, of the resultant neutron source in addition to an analysis of the'contributions by each nuclide in the problem. LASTCALL, a graphical user interface, is included in the code package.

  6. Cold neutron source supercritical, variable speed, magnetic bearing circulator

    NASA Astrophysics Data System (ADS)

    Batton, W. D.; Dillard, J. E.; Lucas, T.; Sundset, K. T.

    2002-05-01

    Intense beams of cold neutrons are used to investigate how materials are assembled at the atomic level. The neutrons are passed through a moderator vessel cooled with hydrogen. One such system under construction at Oak Ridge National Laboratory starts operation at room temperature then cools the hydrogen loop down to the operating point of 17 K. To avoid the liquid to vapor phase changes, the system operates at a supercritical pressure of a 15 bar. The hydrogen prime mover is a centrifugal cryogenic circulator that operates over the entire temperature range. This wide temperature (and corresponding density) range requires wide speed variation in the circulator to maintain the correct moderator cooling flow. Additionally, a requirement for high efficiency at the low temperature normal operating point requires high overall operating speed. The solution to this wide operating range and high efficiency requirement is a circulator that operates continuously between the speeds of 60,000 rpm and 15,000 rpm. Magnetic bearings were selected to make the wide speed range and high speed operation practical and reliable. The resulting design provides 4.15 liters per minute of 288 K hydrogen with a 0.27 bar pressure rise (60,000 rpm) and achieves a flow rate of 1.02 liters per minute of 20 K hydrogen with 1.0 bar pressure rise at the normal operating condition (15,000 rpm).

  7. The advanced neutron source--designing to meet the needs of the user community

    SciTech Connect

    Peretz, F.J. )

    1989-01-01

    The Advanced Neutron Source (ANS) is to be a multi-purpose neutron research center, constructed around a high-flux reactor now being designed at the Oak Ridge National Laboratory (ORNL). Its primary purpose is to place the United States in the forefront of neutron scattering in the twenty-first century. Other research programs include nuclear and fundamental physics, isotopes production, materials irradiation, and analytical chemistry. The Advanced Neutron Source will be a unique and invaluable research tool because of the unprecedented neutron flux available from the high intensity research reactor. But that reactor would be ineffective without world-class research facilities that allow the fullest utilization of the available neutrons. And, in turn, those research facilities will not produce new and exciting science without a broad population of users coming from all parts of the nation, and the world, placed in a simulating environment in which experiments can be effectively conducted, and in which scientific exchange is encouraged. This paper discusses the measures being taken to ensure that the design of the ANS focuses not only on the reactor, but on providing the experiment and user support facilities needed to allow its effective use. 5 refs., 4 figs.

  8. A feasibility study of the Tehran research reactor as a neutron source for BNCT.

    PubMed

    Kasesaz, Yaser; Khalafi, Hossein; Rahmani, Faezeh; Ezati, Arsalan; Keyvani, Mehdi; Hossnirokh, Ashkan; Shamami, Mehrdad Azizi; Monshizadeh, Mahdi

    2014-08-01

    Investigation on the use of the Tehran Research Reactor (TRR) as a neutron source for Boron Neutron Capture Therapy (BNCT) has been performed by calculating and measuring energy spectrum and the spatial distribution of neutrons in all external irradiation facilities, including six beam tubes, thermal column, and the medical room. Activation methods with multiple foils and a copper wire have been used for the mentioned measurements. The results show that (1) the small diameter and long length beam tubes cannot provide sufficient neutron flux for BNCT; (2) in order to use the medical room, the TRR core should be placed in the open pool position, in this situation the distance between the core and patient position is about 400 cm, so neutron flux cannot be sufficient for BNCT; and (3) the best facility which can be adapted for BNCT application is the thermal column, if all graphite blocks can be removed. The epithermal and fast neutron flux at the beginning of this empty column are 4.12×10(9) and 1.21×10(9) n/cm(2)/s, respectively, which can provide an appropriate neutron beam for BNCT by designing and constructing a proper Beam Shaping Assembly (BSA) structure. PMID:24742535

  9. High yield neutron generator based on a high-current gasdynamic electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Skalyga, V.; Izotov, I.; Golubev, S.; Sidorov, A.; Razin, S.; Strelkov, A.; Tarvainen, O.; Koivisto, H.; Kalvas, T.

    2015-09-01

    In present paper, an approach for high yield compact D-D neutron generator based on a high current gasdynamic electron cyclotron resonance ion source is suggested. Results on dense pulsed deuteron beam production with current up to 500 mA and current density up to 750 mA/cm2 are demonstrated. Neutron yield from D2O and TiD2 targets was measured in case of its bombardment by pulsed 300 mA D+ beam with 45 keV energy. Neutron yield density at target surface of 109 s-1 cm-2 was detected with a system of two 3He proportional counters. Estimations based on obtained experimental results show that neutron yield from a high quality TiD2 target bombarded by D+ beam demonstrated in present work accelerated to 100 keV could reach 6 × 1010 s-1 cm-2. It is discussed that compact neutron generator with such characteristics could be perspective for a number of applications like boron neutron capture therapy, security systems based on neutron scanning, and neutronography.

  10. GEANT4 and PHITS simulations of the shielding of neutrons from $^{252}$Cf source

    E-print Network

    Shin, Jae Won

    2014-01-01

    Neutron shielding simulations by using GEANT4 and PHITS code are performed. As a neutron source, $^{252}$Cf is considered and the energy distribution of the neutrons emitted from $^{252}$Cf is assumed the Watt fission spectrum. The neutron dose equivalent rates with and without the shield are estimated for shielding materials such as graphite, iron, polyethylene, NS-4-FR and KRAFTON-HB. For the neutron shielding simulations by using GEANT4, high precision (G4HP) model with G4NDL 4.2 based on ENDF-VII data are used. And for PHITS simulations, JENDL-4.0 library are used for the same purpose. It is found that differences between the shielding calculations by using GEANT4 with G4NDL 4.2 and PHITS with JENDL-4.0 library are not significant for all cases considered in this work. We investigate the accuracy of the neutron dose equivalent rates obtained from GEANT4 and PHITS by comparing our simulation results with experimental data and other values calculated earlier. Calculated neutron dose equivalent rates agree w...

  11. Characteristics of the simulated workplace neutron fields using a 252Cf source surrounded with cylindrical moderators.

    PubMed

    Tsujimura, N; Yoshida, T

    2004-01-01

    The authors established the simulated workplace neutron fields using a 252Cf source surrounded with cylindrical moderators at the Japan Nuclear Cycle Development Institute (JNC), Tokai Works. The moderators are annular cylinders made of polymethyl methacrylate and steel. The neutron energy spectrum at the reference calibration point was evaluated from the calculations by MCNP-4B and the measurements by the Bonner multisphere spectrometer and the hydrogen-filled proportional counters. The calculated neutron spectra were in good agreements with the measured ones. These fields can provide the realistic neutron spectra similar to those encountered around the glove-boxes of the fabrication process of MOX (PuO2-UO2 mixed oxide) fuel. PMID:15353633

  12. Source test of the prototype neutron detector for the large-acceptance multipurpose spectrometer at RAON

    NASA Astrophysics Data System (ADS)

    Lee, Kisoo; Lee, Kyong Sei; Mulilo, Benard; Hong, Byungsik

    2013-05-01

    A neutron detector array will be essential for the study of the nuclear symmetry energy in the large-acceptance multipurpose spectrometer (LAMPS) at the planned rare-isotope beam facility RAON in Korea. We have built the prototype neutron detector for LAMPS and examined its performance by using radiation sources. For data taking, we tested the voltage-threshold discriminator (VTD) and the constant-fraction discriminator (CFD) modules for the pulse process. The intrinsic time resolution of the prototype detector is estimated to be 723 ps for VTD and 488 ps for CFD. The fission neutrons and gammas emitted from 252Cf can be clearly separated in the time distribution. We reconstruct the energy spectrum of the spontaneous fission neutrons from 252Cf, which can be described well by using the empirical Watt spectrum.

  13. Neutron Generation in a Vacuum Diode with Laser-plasma Source of Deuterons

    NASA Astrophysics Data System (ADS)

    Kozlovskij, K. I.; Vovchenko, E. D.; Isaev, A. A.

    The generation of neutrons in a coaxial vacuum diode with laser-plasma source of deuteron on anode and outer hollow cylindrical cathode is investigated. The experiments were carried out at accelerating voltages in the diode gap of UA ? 280 kV for two configurations of the electrode system: the cathode made from magnetic NdFeB compound material, providing suppression of electrons stray currents in the accelerating gap, and an aluminum A1 cathode. For the magnetic field inductance on the axis of the NdFeB cathode about B ? 0.4 on the D(d, n)3He reaction the maximum neutron output in the total solid angle Q = 5×107 neutrons per pulse was received. The absence of magnetic insulation reduced the accelerating voltage on the diode gap and the neutrons output.

  14. Optimizing moderation of He-3 neutron detectors for shielded fission sources

    SciTech Connect

    Rees, Lawrence B.; Czirr, J. Bart

    2012-07-10

    Abstract: The response of 3-He neutron detectors is highly dependent on the amount of moderator incorporated into the detector system. If there is too little moderation, neutrons will not react with the 3-He. If there is too much moderation, neutrons will not reach the 3-He. In applications for portal or border monitors where 3He detectors are used to interdict illicit Importation of plutonium, the fission source is always shielded to some extent. Since the energy distribution of neutrons emitted from the source depends on the amount and type of shielding present, the optimum placement of moderating material around 3-He tubes is a function of shielding. In this paper, we use Monte Carlo techniques to model the response of 3-He tubes placed in polyethylene boxes for moderation. To model the shielded fission neutron source, we use a 252-Cf source placed in the center of spheres of water of varying radius. Detector efficiency as a function of box geometry and shielding are explored. We find that increasing the amount of moderator behind and to the sides of the detector generally improves the detector response, but that benefits are limited if the thickness of the polyethylene moderator is greater than about 5-7 cm. The thickness of the moderator in front of the 3He tubes, however, is very important. For bare sources, about 5-6 cm of moderator is optimum, but as the shielding increases, the optimum thickness of this moderator decreases to 0-1 cm. A two-tube box with a moderator thickness of 5 cm in front of the first tube and a thickness of 1 cm in front of the second tube is proposed to improve the detector's sensitivity to lower-energy neutrons.

  15. Optimizing moderation of He-3 neutron detectors for shielded fission sources

    DOE PAGESBeta

    Rees, Lawrence B.; Czirr, J. Bart

    2012-07-10

    Abstract: The response of 3-He neutron detectors is highly dependent on the amount of moderator incorporated into the detector system. If there is too little moderation, neutrons will not react with the 3-He. If there is too much moderation, neutrons will not reach the 3-He. In applications for portal or border monitors where 3He detectors are used to interdict illicit Importation of plutonium, the fission source is always shielded to some extent. Since the energy distribution of neutrons emitted from the source depends on the amount and type of shielding present, the optimum placement of moderating material around 3-He tubesmore »is a function of shielding. In this paper, we use Monte Carlo techniques to model the response of 3-He tubes placed in polyethylene boxes for moderation. To model the shielded fission neutron source, we use a 252-Cf source placed in the center of spheres of water of varying radius. Detector efficiency as a function of box geometry and shielding are explored. We find that increasing the amount of moderator behind and to the sides of the detector generally improves the detector response, but that benefits are limited if the thickness of the polyethylene moderator is greater than about 5-7 cm. The thickness of the moderator in front of the 3He tubes, however, is very important. For bare sources, about 5-6 cm of moderator is optimum, but as the shielding increases, the optimum thickness of this moderator decreases to 0-1 cm. A two-tube box with a moderator thickness of 5 cm in front of the first tube and a thickness of 1 cm in front of the second tube is proposed to improve the detector's sensitivity to lower-energy neutrons.« less

  16. Neutron imaging with coded sources: new challenges and the implementation of a simultaneous iterative reconstruction technique

    SciTech Connect

    Santos-Villalobos, Hector J; Bingham, Philip R; Gregor, Jens

    2013-01-01

    The limitations in neutron flux and resolution (L/D) of current neutron imaging systems can be addressed with a Coded Source Imaging system with magnification (xCSI). More precisely, the multiple sources in an xCSI system can exceed the flux of a single pinhole system for several orders of magnitude, while maintaining a higher L/D with the small sources. Moreover, designing for an xCSI system reduces noise from neutron scattering, because the object is placed away from the detector to achieve magnification. However, xCSI systems are adversely affected by correlated noise such as non-uniform illumination of the neutron source, incorrect sampling of the coded radiograph, misalignment of the coded masks, mask transparency, and the imperfection of the system Point Spread Function (PSF). We argue that a model-based reconstruction algorithm can overcome these problems and describe the implementation of a Simultaneous Iterative Reconstruction Technique algorithm for coded sources. Design pitfalls that preclude a satisfactory reconstruction are documented.

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

    SciTech Connect

    Doyle, Barney Lee; King, Michael; Rossi, Paolo; McDaniel, Floyd Del; Morse, Daniel Henry; Antolak, Arlyn J.; Provencio, Paula Polyak; 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.

  18. Benchmarking shielding simulations for an accelerator-driven spallation neutron source

    NASA Astrophysics Data System (ADS)

    Cherkashyna, Nataliia; DiJulio, Douglas D.; Panzner, Tobias; Rantsiou, Emmanouela; Filges, Uwe; Ehlers, Georg; Bentley, Phillip M.

    2015-08-01

    The shielding at an accelerator-driven spallation neutron facility plays a critical role in the performance of the neutron scattering instruments, the overall safety, and the total cost of the facility. Accurate simulation of shielding components is thus key for the design of upcoming facilities, such as the European Spallation Source (ESS), currently in construction in Lund, Sweden. In this paper, we present a comparative study between the measured and the simulated neutron background at the Swiss Spallation Neutron Source (SINQ), at the Paul Scherrer Institute (PSI), Villigen, Switzerland. The measurements were carried out at several positions along the SINQ monolith wall with the neutron dosimeter WENDI-2, which has a well-characterized response up to 5 GeV. The simulations were performed using the Monte-Carlo radiation transport code geant4, and include a complete transport from the proton beam to the measurement locations in a single calculation. An agreement between measurements and simulations is about a factor of 2 for the points where the measured radiation dose is above the background level, which is a satisfactory result for such simulations spanning many energy regimes, different physics processes and transport through several meters of shielding materials. The neutrons contributing to the radiation field emanating from the monolith were confirmed to originate from neutrons with energies above 1 MeV in the target region. The current work validates geant4 as being well suited for deep-shielding calculations at accelerator-based spallation sources. We also extrapolate what the simulated flux levels might imply for short (several tens of meters) instruments at ESS.

  19. Research and Development of Landmine Detection System by a Compact Fusion Neutron Source

    SciTech Connect

    Yoshikawa, Kiyoshi; Masuda, Kai; Toku, Hisayuki; Nagasaki, Kazunobu; Mizutani, Toshiyuki; Takamatsu, Teruhisa; Imoto, Masaki; Yamamoto, Yasushi; Ohnishi, Masami; Osawa, Hodaka; Hotta, Eiki; Kohno, Toshiyuki; Okino, Akitoshi; Watanabe, Masato; Yamauchi, Kunihito; Yuura, Morimasa; Shiroya, Seiji; Misawa, Tsuyoshi; Mori, Takamasa

    2005-05-15

    Current results are described on the research and development of an advanced anti-personnel landmine detection system by using a compact discharge-type fusion neutron source called IECF (Inertial-Electrostatic Confinement Fusion). Landmines are to be identified through backscattering of neutrons, and specific-energy capture {gamma}-rays by hydrogen and nitrogen atoms in the landmine explosives.For this purpose, improvements in the IECF were made by various methods to achieve a drastic enhancement of neutron yields of more than 10{sup 8} n/s in pulsed operation. This required R and D on the power source, as well as analysis of envisaged detection systems with multi-sensors. The results suggest promising and practical features for humanitarian landmine detection, particularly, in Afghanistan.

  20. Experiment Automation with a Robot Arm using the Liquids Reflectometer Instrument at the Spallation Neutron Source

    SciTech Connect

    Zolnierczuk, Piotr A; Vacaliuc, Bogdan; Sundaram, Madhan; Parizzi, Andre A; Halbert, Candice E; Hoffmann, Michael C; Greene, Gayle C; Browning, Jim; Ankner, John Francis

    2013-01-01

    The Liquids Reflectometer instrument installed at the Spallation Neutron Source (SNS) enables observations of chemical kinetics, solid-state reactions and phase-transitions of thin film materials at both solid and liquid surfaces. Effective measurement of these behaviors requires each sample to be calibrated dynamically using the neutron beam and the data acquisition system in a feedback loop. Since the SNS is an intense neutron source, the time needed to perform the measurement can be the same as the alignment process, leading to a labor-intensive operation that is exhausting to users. An update to the instrument control system, completed in March 2013, implemented the key features of automated sample alignment and robot-driven sample management, allowing for unattended operation over extended periods, lasting as long as 20 hours. We present a case study of the effort, detailing the mechanical, electrical and software modifications that were made as well as the lessons learned during the integration, verification and testing process.

  1. Saturn Neutron Exosphere as Source for Inner and Innermost Radiation Belts

    NASA Technical Reports Server (NTRS)

    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 (<10 MeV) protons in the inner belt region. Either the source of these lower energy protons is also 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 water molecules. But one must then account somehow for local acceleration to the observed keV-MeV energies, since moon sweeping and E-ring absorption would remove protons diffusing inward from the middle magnetosphere. Although the main rings block further inward diffusion from the inner radiation belts, the exospheric neutron-decay source, combined with much slower diffusion of protons relative to electrons, may produce an innermost radiation belt in the gap between the upper atmosphere and the D-ring. This innermost belt will first be explored in-situ during the final proximal orbits of the Cassini mission.

  2. A Fast Pulse, High Intensity Neutron Source Based Upon The Dense Plasma Focus

    SciTech Connect

    Krishnan, M.; Bures, B.; Madden, R.; Blobner, F.; Elliott, K. Wilson

    2009-12-02

    Alameda Applied Sciences Corporation (AASC) has built a bench-top source of fast neutrons (approx10-30 ns, 2.45 MeV), that is portable and can be scaled to operate at approx100 Hz. The source is a Dense Plasma Focus driven by three different capacitor banks: a 40 J/30 kA/100 Hz driver; a 500 J/130 kA/2 Hz driver and a 3 kJ/350 kA/0.5 Hz driver. At currents of approx130 kA, this source produces approx1x10{sup 7} (DD) n/pulse. The neutron pulse widths are approx10-30 ns and may be controlled by adjusting the DPF electrode geometry and operating parameters. This paper describes the scaling of the fast neutron output with current from such a Dense Plasma Focus source. For each current and driver, different DPF head designs are required to match to the current rise-time, as the operating pressure and anode radius/shape are varied. Doping of the pure D{sub 2} gas fill with Ar or Kr was shown earlier to increase the neutron output. Results are discussed in the light of scaling laws suggested by prior literature.

  3. Summary of mirror experiments relevant to beam-plasma neutron source

    SciTech Connect

    Molvik, A.W.

    1988-10-18

    A promising design for a deuterium-tritium (DT) neutron source is based on the injection of neutral beams into a dense, warm plasma column. Its purpose is to test materials for possible use in fusion reactors. A series of designs have evolved, from a 4-T version to an 8-T version. Intense fluxes of 5--10 MW/m/sup 2/ is achieved at the plasma surface, sufficient to complete end-of-life tests in one to two years. In this report, we review data from earlier mirror experiments that are relevant to such neutron sources. Most of these data are from 2XIIB, which was the only facility to ever inject 5 MW of neutral beams into a single mirror call. The major physics issues for a beam-plasma neutron source are magnetohydrodynamic (MHD) equilibrium and stability, microstability, startup, cold-ion fueling of the midplane to allow two-component reactions, and operation in the Spitzer conduction regime, where the power is removed to the ends by an axial gradient in the electron temperature T/sub e/. We show in this report that the conditions required for a neutron source have now been demonstrated in experiments. 20 refs., 15 figs., 3 tabs.

  4. Applications of compact accelerator-driven neutron sources: An updated assessment from the perspective of materials research in Italy

    SciTech Connect

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

    2014-12-24

    In 2005 the International Atomic Energy Agency (IAEA) in Vienna published a report [1] on ‘Development Opportunities of Small and Medium Scale Accelerator Driven Neutron Sources’ which summarized the prospect of smaller sources in supporting the large spallation neutron sources for materials characterization and instrumentation, a theme advocated by Bauer, Clausen, Mank, and Mulhauser in previous publications [2-4]. In 2010 the Union for Compact Accelerator-driven Neutron Sources (UCANS) was established [5], galvanizing cross-disciplinary collaborations on new source and neutronics development and expanded applications based on both slow-neutron scattering and other neutron-matter interactions of neutron energies ranging from 10?? to 10² MeV [6]. Here, we first cover the recent development of ongoing and prospective projects of compact accelerator-driven neutron sources (CANS) but concentrate on prospective accelerators currently proposed in Italy. Two active R&D topics, irradiation effects on electronics and cultural heritage studies, are chosen to illustrate the impact of state-of-the-art CANS on these programs with respect to the characteristics and complementarity of the accelerator and neutronics systems as well as instrumentation development.

  5. Applications of compact accelerator-driven neutron sources: An updated assessment from the perspective of materials research in Italy

    DOE PAGESBeta

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

    2014-12-24

    In 2005 the International Atomic Energy Agency (IAEA) in Vienna published a report [1] on ‘Development Opportunities of Small and Medium Scale Accelerator Driven Neutron Sources’ which summarized the prospect of smaller sources in supporting the large spallation neutron sources for materials characterization and instrumentation, a theme advocated by Bauer, Clausen, Mank, and Mulhauser in previous publications [2-4]. In 2010 the Union for Compact Accelerator-driven Neutron Sources (UCANS) was established [5], galvanizing cross-disciplinary collaborations on new source and neutronics development and expanded applications based on both slow-neutron scattering and other neutron-matter interactions of neutron energies ranging from 10?? to 10²more »MeV [6]. Here, we first cover the recent development of ongoing and prospective projects of compact accelerator-driven neutron sources (CANS) but concentrate on prospective accelerators currently proposed in Italy. Two active R&D topics, irradiation effects on electronics and cultural heritage studies, are chosen to illustrate the impact of state-of-the-art CANS on these programs with respect to the characteristics and complementarity of the accelerator and neutronics systems as well as instrumentation development.« less

  6. The performance of neutron scattering spectrometers at a long-pulse spallation source

    SciTech Connect

    Pynn, R.

    1997-06-01

    In this document the author considers the performance of a long pulse spallation source for those neutron scattering experiments that are usually performed with a monochromatic beam at a continuous wave (CW) source such as a nuclear reactor. The first conclusion drawn is that comparison of the performance of neutron scattering spectrometers at CW and pulsed sources is simpler for long-pulsed sources than it is for the short-pulse variety. Even though detailed instrument design and assessment will require Monte Carlo simulations (which have already been performed at Los Alamos for SANS and reflectometry), simple arguments are sufficient to assess the approximate performance of spectrometers at an LPSS and to support the contention that a 1 MW long-pulse source can provide attractive performance, especially for instrumentation designed for soft-condensed-matter science. Because coupled moderators can be exploited at such a source, its time average cold flux is equivalent to that of a research reactor with a power of about 15 MW, so only a factor of 4 gain from source pulsing is necessary to obtain performance that is comparable with the ILL. In favorable cases, the gain from pulsing can be even more than this, approaching the limit set by the peak flux, giving about 4 times the performance of the ILL. Because of its low duty factor, an LPSS provides the greatest performance gains for relatively low resolution experiments with cold neutrons. It should thus be considered complementary to short pulse sources which are most effective for high resolution experiments using thermal or epithermal neutrons.

  7. Coherent Scattering Investigations at the Spallation Neutron Source: a Snowmass White Paper

    SciTech Connect

    Akimov, D. Moscow Engineering Physics Institute , Russia; Bernstein, A. Lawrence Livermore National Laboratory; BarbeauP.,; Barton, P. J. Lawrence Berkeley National Laboratory; Bolozdynya, A. Moscow Engineering Physics Institute , Russia; Cabrera-Palmer, B. Sandia National Laboratories; Cavanna, F. Yale University; Cianciolo, Vince ORNL; Collar, J. University of Chicago, Enrico Fermi Institute; Cooper, R. J. Indiana University; Dean, D. J. Oak Ridge National Laboratory; Efremenko, Yuri University of Tennessee and Oak Ridge National Laboratory; Etenko, A. Moscow Engineering Physics Institute , Russia; Fields, N. University of Chicago, Enrico Fermi Institute; Foxe, M. Pennsylvania State University, University Park, PA; Figueroa-Feliciano, E. Massachusetts Institute of Technology; Fomin, N. University of Tennessee, Knoxville; Gallmeier, F. Oak Ridge National Laboratory; Garishvili, I. University of Tennessee, Knoxville; Gerling, M. Sandia National Laboratories; Green, M. University of North Carolina, Chapel Hill; Greene, Geoffrey University of Tennessee, Knoxville; Hatzikoutelis, A. University of Tennessee, Knoxville; Henning, Reyco University of North Carolina, Chapel Hill; Hix, R. University of Tennessee and Oak Ridge National Laboratory; Hogan, D. University of California-Berkeley; Hornback, D. University of Tennessee and Oak Ridge National Laboratory; Jovanovic, I. Pennsylvania State University, University Park, PA; Hossbach, T. Pacific Northwest National Laboratory; Iverson, Erik B ORNL; Klein, S. R. Lawrence Berkeley National Laboratory; Khromov, A. Moscow Engineering Physics Institute , Russia; Link, J. Virginia Polytechnic Institute and State University; Louis, W. Los Alamos National Laboratory; Lu, W. Oak Ridge National Laboratory; Mauger, C. Los Alamos National Laboratory; Marleau, P. Sandia National Laboratories; Markoff, D. North Carolina Central University, Durham; Martin, R. D. University of South Dakota; Mueller, Paul Edward ORNL; Newby, J. Oak Ridge National Laboratory; Orrell, John L. Pacific Northwest National Laboratory; O'Shaughnessy, C. University of North Carolina, Chapel Hill; Penttila, Seppo Oak Ridge National Laboratory; Patton, K. North Carolina State University, Raleigh; Poon, A. W. Lawrence Berkeley National Laboratory; Radford, David C ORNL; Reyna, D. Sandia National Laboratories; Ray, H. University of Florida, Gainesville; Scholberg, K. Duke University, North Carolina; Sosnovtsev, V. Moscow Engineering Physics Institute , Russia; Tayloe, R. Indiana University; Vetter, K. Lawrence Berkeley National Laboratory; Virtue, C. Laurentian University, Canada; Wilkerson, J. University of North Carolina, Chapel Hill; Yoo, J. Fermi National Accelerator Laboratory; Yu, Chang-Hong ORNL

    2013-01-01

    The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, Tennessee, provides an intense flux of neutrinos in the few tens-of-MeV range, with a sharply-pulsed timing structure that is beneficial for background rejection. In this white paper, we describe how the SNS source can be used for a measurement of coherent elastic neutrino-nucleus scattering (CENNS), and the physics reach of different phases of such an experimental program (CSI: Coherent Scattering Investigations at the SNS).

  8. The performance of neutron scattering spectrometers at a long-pulse spallation source

    SciTech Connect

    Pynn, R.

    1995-04-01

    The first conclusion the author wants to draw is that comparison of the performance of neutron scattering spectrometers at CW and pulsed sources is simpler for long-pulsed sources than it is for the short-pulse variety. Even though detailed instrument design and assessment will require Monte Carlo simulations (which have already been performed at Los Alamos for SANS and reflectometry), simple arguments are sufficient to assess the approximate performance of spectrometers at an LPSS and to support the contention that a 1 MW long-pulse source can provide attractive performance, especially for instrumentation designed for soft-condensed-matter science. Because coupled moderators can be exploited at such a source, its time average cold flux is equivalent to that of a research reactor with a power of about 15 MW, so only a factor of 4 gain from source pulsing is necessary to obtain performance that is comparable with the ILL. In favorable cases, the gain from pulsing can be even more than this, approaching the limit set by the peak flux, giving about 4 times the performance of the ILL. Because of its low duty factor, an LPSS provides the greatest performance gains for relatively low resolution experiments with cold neutrons. It should thus be considered complementary to short pulse sources which are most effective for high resolution experiments using thermal or epithermal neutrons.

  9. Compact sub-kilojoule range fast miniature plasma focus as portable neutron source

    NASA Astrophysics Data System (ADS)

    Verma, Rishi; Roshan, M. V.; Malik, F.; Lee, P.; Lee, S.; Springham, S. V.; Tan, T. L.; Krishnan, M.; Rawat, R. S.

    2008-11-01

    As a first step toward the development of a compact and portable, quasi-continuous pulsed neutron source, we have demonstrated a 'fast miniature plasma focus (PF) device' as a compact nuclear fusion apparatus. The system operates with deuterium gas and produces an average neutron yield (Y90°) of (1 ± 0.27) × 104 neutrons/shot at ~70 kA peak discharge current. In the range of 1.5-4 mbar, a distinct and sharp dip in the current derivative signal indicates a strong pinching action with subsequent emission of hard x-rays followed by a neutron pulse. The yield and the time history of the neutrons were measured by both active and passive detection techniques (such as a 3He proportional counter, NE102A plastic scintillator and CR-39 SSNTDs). The overall dimensions of the apparatus, which includes a capacitor bank, sparkgap switch and the focus chamber, are 0.2 m × 0.2 m × 0.5 m and the total mass of the system is ~25 kg. The scope of this paper is to evaluate/demonstrate the potential of such a fast miniature PF device as a compact and portable fusion apparatus producing neutrons while operating at relatively low energy.

  10. The PSI ultra-cold neutron source A. Anghel a

    E-print Network

    Zejma, Jacek

    with a fast kicker magnet [3] into a beam line leading to the UCN source. The duty cycle is 1%, e.g. the pulse of an electrostatic splitter (EHT, see Fig. 1) situated very close to the kicker magnet in order to have almost

  11. High-flux neutron source based on a liquid-lithium target

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    A prototype compact Liquid Lithium Target (LiLiT), able to constitute an accelerator-based intense neutron source, was built. The neutron source is intended for nuclear astrophysical research, boron neutron capture therapy (BNCT) in hospitals and material studies for fusion reactors. The LiLiT setup is presently being commissioned at Soreq Nuclear research Center (SNRC). The lithium target will produce neutrons through the 7Li(p,n)7Be reaction and it will overcome the major problem of removing the thermal power generated by a high-intensity proton beam, necessary for intense neutron flux for the above applications. The liquid-lithium loop of LiLiT is designed to generate a stable lithium jet at high velocity on a concave supporting wall with free surface toward the incident proton beam (up to 10 kW). During off-line tests, liquid lithium was flown through the loop and generated a stable jet at velocity higher than 5 m/s on the concave supporting wall. The target is now under extensive test program using a high-power electron-gun. Up to 2 kW electron beam was applied on the lithium flow at velocity of 4 m/s without any flow instabilities or excessive evaporation. High-intensity proton beam irradiation will take place at SARAF (Soreq Applied Research Accelerator Facility) superconducting linear accelerator currently in commissioning at SNRC.

  12. Monte Carlo Simulations of the Response of Shielded SNM to a Pulsed Neutron Source

    SciTech Connect

    E.H. Seabury; D.L. Chichester

    2010-08-01

    Active interrogation (AI) has been used as a technique for the detection and identification of Special Nuclear Material (SNM) for both proposed and field-tested systems. Idaho National Laboratory (INL) has been studying this technique for systems ranging from small systems employing portable electronic neutron generators (ENGs) 1 to larger systems employing linear accelerators as high-energy photon sources for assessment of vehicles and cargo2. In order to assess the feasibility of new systems, INL has undertaken a campaign of Monte Carlo simulations of the response of a variety of masses of SNM in multiple shielding configurations to a pulsed neutron source using the MCNPX3 code, with emphasis on the neutron and photon response of the system as a function of time after the initial neutron pulse. We present here some preliminary results from these calculations. 1. D.L. Chichester and E.H. Seabury, “ Using Electronic Neutron Generators in Active Interrogation to Detect Shielded Nuclear Material,” IEEE Transactions on Nuclear Science 56 (2009) pp 441-447. 2. J.L. Jones et al., “Photonuclear-based, nuclear material detection system for cargo containers,” Nuclear Instruments and Methods in Physics Research B 241 (2005) pp 770-776. 3. D.B. Pelowitz, “MCNPXTM User’s Manual version 2.6.0,” Los Alamos National Laboratory Report LA-CP-07-1473 (2008).

  13. High-flux neutron source based on a liquid-lithium target

    SciTech Connect

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

    2013-04-19

    A prototype compact Liquid Lithium Target (LiLiT), able to constitute an accelerator-based intense neutron source, was built. The neutron source is intended for nuclear astrophysical research, boron neutron capture therapy (BNCT) in hospitals and material studies for fusion reactors. The LiLiT setup is presently being commissioned at Soreq Nuclear research Center (SNRC). The lithium target will produce neutrons through the {sup 7}Li(p,n){sup 7}Be reaction and it will overcome the major problem of removing the thermal power generated by a high-intensity proton beam, necessary for intense neutron flux for the above applications. The liquid-lithium loop of LiLiT is designed to generate a stable lithium jet at high velocity on a concave supporting wall with free surface toward the incident proton beam (up to 10 kW). During off-line tests, liquid lithium was flown through the loop and generated a stable jet at velocity higher than 5 m/s on the concave supporting wall. The target is now under extensive test program using a high-power electron-gun. Up to 2 kW electron beam was applied on the lithium flow at velocity of 4 m/s without any flow instabilities or excessive evaporation. High-intensity proton beam irradiation will take place at SARAF (Soreq Applied Research Accelerator Facility) superconducting linear accelerator currently in commissioning at SNRC.

  14. Advantages and limitations of nuclear physics experiments at an ISIS-class spallation neutron source

    NASA Astrophysics Data System (ADS)

    Mocko, M.; Muhrer, G.; Tovesson, F.

    2008-05-01

    Nuclear physics experiments have a long history of being conducted on spallation neutron sources. Like other experiments, these measurements take advantage of the identification of the incident neutron energy by the time-of-flight (ToF) technique. However, in some ways these experiments are often in direct conflict with other experiments. Especially in large (ISIS or SNS class) facilities, the design of the source often reflects a compromise between different experimental needs and requirements. It has been a long standing question for nuclear physics experiments how limiting these compromises are and how they can be dealt with. We have therefore calculated the incident neutron energy spectrum, along with the gamma background spectrum, for flight path (FP) 5 at the Los Alamos Neutron Science Center (LANSCE) Manuel Lujan Jr. Neutron Scattering Center (Lujan Center) including a detailed evaluation of the signal shape. We will discuss the advantages and limitations of the nuclear physics experiments at FP-5 in the light of our results.

  15. New opportunities for quasielastic and inelastic neutron scattering at steady-state sources using mechanical selection of the incident and final neutron energy

    DOE PAGESBeta

    Mamantov, Eugene

    2015-06-12

    We propose a modification of the neutron wide-angle velocity selector (WAVES) device that enables inelastic (in particular, quasielastic) scattering measurements not relying on the neutron time-of-flight. The proposed device is highly suitable for a steady-state neutron source, somewhat similar to a triple-axis spectrometer, but with simultaneous selection of the incident and final neutron energy over a broad range of scattering momentum transfer. Both the incident and final neutron velocities are defined by the WAVES geometry and rotation frequency. The variable energy transfer is achieved through the natural variation of the velocity of the transmitted neutrons as a function of themore »scattering angle component out of the equatorial plane.« less

  16. Impact of switching to the ICRP-74 neutron flux-to-dose equivalent rate conversion factors at the Sandia National Laboratory Building 818 Neutron Source Range.

    SciTech Connect

    Ward, Dann C.

    2009-03-01

    Sandia National Laboratories (SNL) maintains a neutron calibration facility which supports the calibration, maintenance, and repair of Radiation Protection Instruments. The SNL neutron reference fields are calibrated using the following methodology: Fluence rate is initially established by calculation using the NIST traceable source emission rate (decay corrected). Correction factors for the effects of room return or scatter, and source anisotropy are then developed by using a suitable radiation transport code to model the geometry of the facility. The conventionally true neutron dose rates are then determined using the appropriate fluence-todose equivalent conversion coefficients at several reference positions. This report describes the impact on calculated neutron dose rates of switching from NCRP-38 to CRP-74 neutron flux-todose equivalent rate conversion factors. This switch is driven by recent changes to dosimetry requirements addressed in 10 CFR 835 (Occupational Radiation Protection).

  17. Compact Short-Pulsed Electron Linac Based Neutron Sources for Precise Nuclear Material Analysis

    NASA Astrophysics Data System (ADS)

    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 the operation and measurement.

  18. Flux stabilization in neutron problems with fixed sources

    SciTech Connect

    Tomatis, D.; Dall'Osso, A.

    2012-07-01

    Although critical core calculations are the most common in design and safety analysis, fixed source calculations are needed for specific applications, e.g. to compute ex-core detector response functions, to develop new methodologies for dilution and reload error accidents and more in general for all situations involving sub-critical shut-down states. It is well known that the source problem becomes difficult to be solved with core configuration close to criticality, i.e. with the multiplication factor approaching unity, for the occurrence of numerical ill-conditioning and very high number of iterations, possibly leading to failure in the flux convergence. In this work, the Wielandt Eigen-shift technique used in iterative methods of critical problems is developed for source problems too, in order to stabilize the solution. The mathematical basis and the proof of the convergence are discussed. Compared to the existing methods, this technique allows also more control to avoid singular behavior at inner iterations. Numerical tests with a 1D analytical benchmark are reported to prove the robustness of the technique. (authors)

  19. Comparison of LaBr3:Ce and NaI(Tl) Scintillators for Radio-Isotope Identification Devices

    SciTech Connect

    Milbrath, Brian D.; Choate, Bethany J.; Fast, Jim E.; Hensley, Walter K.; Kouzes, Richard T.; Schweppe, John E.

    2006-07-31

    Lanthanum halide (LaBr3:Ce) scintillators offer significantly better resolution (<3 percent at 662 kilo-electron volt [keV]) relative to sodium iodide (NaI(Tl)) and have recently become commercially available in sizes large enough for the hand-held radio-isotope identification device (RIID) market. There are drawbacks to lanthanum halide detectors, however. These include internal radioactivity that contributes to spectral counts and a low-energy response that can cause detector resolution to be lower than that of NaI(Tl) below 100 keV. To study the potential of this new material for RIIDs, we performed a series of measurements comparing a 1.5?1.5 inch LaBr?3:Ce detector with an Exploranium GR 135 RIID, which contains a 1.5-2.2 inch NaI(Tl) detector. Measurements were taken for short time frames, as typifies RIID usage. Measurements included examples of naturally occurring radioactive material (NORM), typically found in cargo, and special nuclear materials. Some measurements were noncontact, involving short distances or cargo shielding scenarios. To facilitate direct comparison, spectra from the different detectors were analyzed with the same isotope identification software (ORTEC ScintiVision TM). In general, the LaBr3:Ce detector was able to find more peaks and find them faster than the NaI(Tl) detector. To the same level of significance, the LaBr3:Ce detector was usually two to three times faster. The notable exception was for 40K containing NORM where interfering internal contamination in the LaBr3:Ce detector exist. NaI(Tl) consistently outperformed LaBr3:Ce for this important isotope. LaBr3:Ce currently costs much more than NaI(Tl), though this cost-difference is expected to diminish (but not completely) with time. As is true of all detectors, LaBr3:Ce will need to be gain-stabilized for RIID applications. This could possibly be done using the internal contaminants themselves. It is the experience of the authors that peak finding software in RIIDs needs to be improved, regardless of the detector material.

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

    PubMed

    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 5ppm 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

  1. The Impact of Pulsed Spallation Neutron Sources on Condensed Matter Research

    NASA Astrophysics Data System (ADS)

    Finney, J. L.

    1993-03-01

    The exploitation of neutron scattering techniques in studies of the structure and dynamics of condensed matter has been one of the major scientific successes of the past 20 years. Based initially on high flux reactors, which produce continuous beams of neutrons, a wide range of pure and applied problems in physics, chemistry, biological sciences, engineering, materials and earth sciences have been tackled, and much new understanding gained. More recently, sources based on proton accelerators have been built, and their particular characteristics - all of which derive from the fact that sharp pulses of neutrons are produced at frequencies of between 20 and 50 Hz - explored. These characteristics, which allow science to be done that would be difficult, inefficient or impossible on a reactor source, have greatly widened the range of scientific problems that can be tackled using neutrons. This chapter gives examples from experiments performed on the most powerful such source - ISIS in the UK - and looks forward briefly to future developments in the next millenium.

  2. Laser fusion neutron source employing compression with short pulse lasers

    DOEpatents

    Sefcik, Joseph A; Wilks, Scott C

    2013-11-05

    A method and system for achieving fusion is provided. The method includes providing laser source that generates a laser beam and a target that includes a capsule embedded in the target and filled with DT gas. The laser beam is directed at the target. The laser beam helps create an electron beam within the target. The electron beam heats the capsule, the DT gas, and the area surrounding the capsule. At a certain point equilibrium is reached. At the equilibrium point, the capsule implodes and generates enough pressure on the DT gas to ignite the DT gas and fuse the DT gas nuclei.

  3. On three-dimensional reconstruction of a neutron/x-ray source from very few two-dimensional projections

    NASA Astrophysics Data System (ADS)

    Volegov, P. L.; Danly, C. R.; Merrill, F. E.; Simpson, R.; Wilde, C. H.

    2015-11-01

    The neutron imaging system at the National Ignition Facility is an important diagnostic tool for measuring the two-dimensional size and shape of the source of neutrons produced in the burning deuterium-tritium plasma during the stagnation phase of inertial confinement fusion implosions. Very few two-dimensional projections of neutron images are available to reconstruct the three-dimensional neutron source. In this paper, we present a technique that has been developed for the 3D reconstruction of neutron and x-ray sources from a minimal number of 2D projections. We present the detailed algorithms used for this characterization and the results of reconstructed sources from experimental data collected at Omega.

  4. STATUS OF THE OAK RIDGE SPALLATION NEUTRON SOURCE (SNS) RF SYSTEMS *

    SciTech Connect

    Crofford, Mark T; Kang, Yoon W; Lee, Sung-Woo; Piller, Chip; Middendorf, Mark E; Vassioutchenko, Alexandre V; Hardek, Thomas W

    2011-01-01

    The SNS has been delivering production neutrons for five years with first beam delivered to the neutron target at the end of April 2006. On September 18, 2009 SNS officially reached 1 megawatt of beam on target marking the achievement of a decades-old dream of providing a U.S. megawatt class pulsed spallation source. The SNS is now routinely delivering 1 megawatt of beam power to the neutron target at over 85 percent of the scheduled beam time. The present effort is aimed at increasing availability eventually to 95 percent and gradually increasing the intensity to the 1.4 megawatt design level. While the RF systems have performed well since initial installation some improvements have been implemented. This paper provides a review of the SNS RF Systems, an overview of the performance of the various components and a detailed review of RF related issues addressed over the past several years.

  5. Relative performance properties of the ORNL Advanced Neutron Source Reactor with reduced enrichment fuels

    SciTech Connect

    Bretscher, M.M.; Deen, J.R.; Hanan, N.A.; Matos, J.E.; Mo, S.C.; Pond, R.B.; Travelli, A.; Woodruff, W.L.

    1994-12-31

    Three cores for the Advanced Neutron Source reactor, differing in size, enrichment, and uranium density in the fuel meat, have been analyzed. Performance properties of the reduced enrichment cores are compared with those of the HEU reference configuration. Core lifetime estimates suggest that none of these configurations will operate for the design goal of 17 days at 330 MW. With modes increases in fuel density and/or enrichment, however, the operating lifetimes of the HEU and MEU designs can be extended to the desired length. Achieving this lifetime with LEU fuel in any of the three studies cores, however, will require the successful development of denser fuels and/or structural materials with thermal neutron absorption cross sections substantially less than that of Al-6061. Relative to the HEU reference case, the peak thermal neutron flux in cores with reduced enrichment will be diminished by about 25--30%.

  6. Measurements of the neutron spectra from the 7Li(p,n) accelerator based neutron source: Position and angular dependences

    NASA Astrophysics Data System (ADS)

    Matysiak, W.; Prestwich, W. V.; Byun, S. H.

    2012-11-01

    Thick target 7Li(p,n) neutron spectra were measured using a 3He ion chamber in the proton energy range of 1.95 to 2.30 MeV. The fast neutron spectra were collected for various distances from the lithium target as well as for various neutron emission angles. By unfolding the 3He raw data with the iterative van Cittert algorithm, the neutron fluence spectra were obtained. The 3He measured neutron spectra were compared with both analytically computed and Monte Carlo simulated spectra to account for neutron scatterings in the lithium target assembly and in the experimental area. To verify the accuracy of the neutron dose computation, the fast neutron kerma was obtained for each neutron spectrum using the fluence to kerma conversion coefficients and was compared with the measured neutron dose using tissue-equivalent proportional counters. In the position dependence investigation at the 0° emission angle, the analytically computed neutron kerma overestimates the experimental kerma by a factor of two mainly due to neutron moderation. The corresponding neutron kerma from the 3He measured spectra were in agreement with the neutron doses measured using tissue-equivalent proportional counters within 20% for lower proton energies, but the discrepancy increased to ˜50% for higher proton energies. In the angular distribution investigation, a notable discrepancy between measured and computed neutron spectra were observed due to the neutron scattering effects in the target assembly and experimental room.

  7. A neutron pinhole camera for PF-24 source: Conceptual design and optimization

    NASA Astrophysics Data System (ADS)

    Bielecki, J.; Wójcik-Gargula, A.; Wiacek, U.; Scholz, M.; Igielski, A.; Drozdowicz, K.; Wo?nicka, U.

    2015-07-01

    A fast-neutron pinhole camera based on small-area (5mm × 5 mm) BCF-12 scintillation detectors with nanosecond time resolution has been designed. The pinhole camera is dedicated to the investigation of the spatial and temporal distributions of DD neutrons from the Plasma Focus (PF-24) source. The geometrical parameters of the camera have been optimized in terms of maximum neutron flux at the imaging plane by means of MCNP calculations. The detection system consists of four closely packed scintillation detectors coupled via long optical fibres to Hamamatsu H3164-10 photomultiplier tubes. The pinhole consists of specially designed 420 mm long copper collimator with an effective aperture of 1.7 mm mounted inside a cylindrical polyethylene tube. The performance of the presented detection system in the mixed (hard X-ray and neutron) radiation field of the PF-24 plasma focus device has been tested. The results of the tests showed that the small-area BCF-12 scintillation detectors can be successfully applied as the detection system of the neutron pinhole camera for the PF-24 device.

  8. Phase 1 environmental report for the Advanced Neutron Source at Oak Ridge National Laboratory

    SciTech Connect

    Blasing, T.J.; Brown, R.A.; Cada, G.F.; Easterly, C.; Feldman, D.L.; Hagan, C.W.; Harrington, R.M.; Johnson, R.O.; Ketelle, R.H.; Kroodsma, R.L.; McCold, L.N.; Reich, W.J.; Scofield, P.A.; Socolof, M.L.; Taleyarkhan, R.P.; Van Dyke, J.W.

    1992-02-01

    The US Department of Energy (DOE) has proposed the construction and operation of the Advanced Neutron Source (ANS), a 330-MW(f) reactor, at Oak Ridge National Laboratory (ORNL) to support neutron scattering and nuclear physics experiments. ANS would provide a steady-state source of neutrons that are thermalized to produce sources of hot, cold, and very coal neutrons. The use of these neutrons in ANS experiment facilities would be an essential component of national research efforts in basic materials science. Additionally, ANS capabilities would include production of transplutonium isotopes, irradiation of potential fusion and fission reactor materials, activation analysis, and production of medical and industrial isotopes such as {sup 252}Cf. Although ANS would not require licensing by the US Nuclear Regulatory Commission (NRC), DOE regards the design, construction, and operation of ANS as activities that would produce a licensable facility; that is, DOE is following the regulatory guidelines that NRC would apply if NRC were licensing the facility. Those guidelines include instructions for the preparation of an environmental report (ER), a compilation of available data and preliminary analyses regarding the environmental impacts of nuclear facility construction and operation. The ER, described and outlined in NRC Regulatory Guide 4.2, serves as a background document to facilitate the preparation of environmental impact statements (EISs). Using Regulatory Guide 4.2 as a model, this ANS ER provides analyses and information specific to the ANS site and area that can be adopted (and modified, if necessary) for the ANS EIS. The ER is being prepared in two phases. Phase 1 ER includes many of the data and analyses needed to prepare the EIS but does not include data or analyses of alternate sites or alternate technologies. Phase 2 ER will include the additional data and analyses stipulated by Regulatory Guide 4.2.

  9. Self characterization of a coded aperture array for neutron source imaging

    SciTech Connect

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

    2014-12-15

    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 stagnation stage of inertial confinement fusion implosions. Since the neutron source is small (?100 ?m) and neutrons are deeply penetrating (>3 cm) in all materials, the apertures used to achieve the desired 10-?m resolution are 20-cm long, triangular tapers machined in gold foils. These gold foils are stacked to form an array of 20 apertures for pinhole imaging and three apertures for penumbral imaging. These apertures must be precisely aligned to accurately place the field of view of each aperture at the design location, or the location of the field of view for each aperture must be measured. In this paper we present a new technique that has been developed for the measurement and characterization of the precise location of each aperture in the array. We present the detailed algorithms used for this characterization and the results of reconstructed sources from inertial confinement fusion implosion experiments at NIF.

  10. Thermal neutron detection system

    DOEpatents

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

    2000-01-01

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

  11. Ion-source and LEBT issues with the front-end systems for the Spallation Neutron Source

    SciTech Connect

    Keller, R.; Cheng, D.; DiGennaro, R.; Gough, R.A.; Greer, J.; Leung, K.N.; Ratti, A.; Reijonen, J.; Thomae, R.W.; Schenkel, T.; Staples, J.W.; Yourd, R.; Aleksandrov, A.; Stockli, M.P.; Welton, R.W.

    2001-09-01

    The Front-End Systems (FES) of the Spallation Neutron Source (SNS) project are being built by Berkeley Lab and will deliver a pulsed 40-mA H{sup -} ion beam at 2.5 MeV energy to the subsequent Drift-Tube Linac. The FES accelerator components comprise an rf driven, volume-production, cesium-enhanced, multi-cusp Ion Source; an electrostatic Low-Energy Beam Transport (LEBT) that includes provisions for transverse focusing, steering, and beam chopping; an RFQ accelerator; and a Medium-Energy Beam Transport (MEBT) line. The challenges for Ion Source and LEBT design are the generation of a plasma suitable for creating the required high H{sup -} ion density, lifetime of the rf antenna at 6% duty factor, removal of the parasitic electron population from the extracted negative ions, and emittance conservation. The paper discusses these issues in detail and highlights key experimental results obtained so far.

  12. Evaluation of two-stage system for neutron measurement aiming at increase in count rate at Japan Atomic Energy Agency-Fusion Neutronics Source

    SciTech Connect

    Shinohara, K. Ochiai, K.; Sukegawa, A.; Ishii, K.; Kitajima, S.; Baba, M.; Sasao, M.

    2014-11-15

    In order to increase the count rate capability of a neutron detection system as a whole, we propose a multi-stage neutron detection system. Experiments to test the effectiveness of this concept were carried out on Fusion Neutronics Source. Comparing four configurations of alignment, it was found that the influence of an anterior stage on a posterior stage was negligible for the pulse height distribution. The two-stage system using 25 mm thickness scintillator was about 1.65 times the count rate capability of a single detector system for d-D neutrons and was about 1.8 times the count rate capability for d-T neutrons. The results suggested that the concept of a multi-stage detection system will work in practice.

  13. Development of high-intensity D-D and D-T neutron sources and neutron filters for medical and industrial applications

    SciTech Connect

    Verbeke, J.M.

    2000-05-10

    This thesis consists of three main parts. The first one relates to boron neutron capture therapy. It summarizes the guidelines obtained by numerical simulations for the treatment of shallow and deep-seated brain tumors, as well as the results on the design of beam-shaping assemblies to moderate D-D and D-T neutrons to epithermal energies. The second part is about boron neutron capture synovectomy for the treatment of rheumatoid arthritis. Optimal neutron energy for treatment and beam-shaping assembly designs are summarized in this section. The last part is on the development of the sealed neutron generator, including experimental results on the prototype ion source and the prototype accelerator column.

  14. (9)Be(d,n)(10)B-based neutron sources for BNCT.

    PubMed

    Capoulat, M E; Herrera, M S; Minsky, D M; González, S J; Kreiner, A J

    2014-06-01

    In the frame of accelerator-based BNCT, the (9)Be(d,n)(10)B reaction was investigated as a possible source of epithermal neutrons. In order to determine the configuration in terms of bombarding energy, target thickness and Beam Shaping Assembly (BSA) design that results in the best possible beam quality, a systematic optimization study was carried out. From this study, the optimal configuration resulted in tumor doses ?40Gy-Eq, with a maximum value of 51Gy-Eq at a depth of about 2.7cm, in a 60min treatment. The optimal configuration was considered for the treatment planning assessment of a real Glioblastoma Multiforme case. From this, the resulted dose performances were comparable to those obtained with an optimized (7)Li(p,n)-based neutron source, under identical conditions and subjected to the same clinical protocol. PMID:24332880

  15. The Mission and Technology of a Gas Dynamic Trap Neutron Source for Fusion Material and Component Testing and Qualification

    SciTech Connect

    Molvik, A W; Simonen, T C

    2009-07-17

    This report summarizes discussions and conclusions of the workshop to 'Assess The Mission and Technology of a Gas Dynamic Trap Neutron Source for Fusion Material and Component Testing and Qualification'. The workshop was held at LBNL, Berkeley, CA on March 12, 2009. Most workshop attendees have worked on magnetic mirror systems, several have worked on similar neutron source designs, and others are knowledgeable of materials, fusion component, and neutral beams The workshop focused on the gas dynamic trap DT Neutron Source (DTNS) concept being developed at the Budker Institute of Nuclear Physics (BINP) in Novosibirsk, Russia. The DTNS may be described as a line source of neutrons, in contrast to a spallation or a D-Lithium source with neutrons beaming from a point, or a tokamak volume source. The DTNS is a neutral beam driven linear plasma system with magnetic mirrors to confine the energetic deuterium and tritium beam injected ions, which produce the 14 MeV neutrons. The hot ions are imbedded in warm-background plasma, which traps the neutral atoms and provides both MHD and micro stability to the plasma. The 14 MeV neutron flux ranges typically at the level of 1 to 4 MW/m2.

  16. Computational characterization and experimental validation of the thermal neutron source for neutron capture therapy research at the University of Missouri

    SciTech Connect

    Broekman, J. D.; Nigg, D. W.; Hawthorne, M. F.

    2013-07-01

    Parameter studies, design calculations and neutronic performance measurements have been completed for a new thermal neutron beamline constructed for neutron capture therapy cell and small-animal radiobiology studies at the University of Missouri Research Reactor. The beamline features the use of single-crystal silicon and bismuth sections for neutron filtering and for reduction of incident gamma radiation. The computational models used for the final beam design and performance evaluation are based on coupled discrete-ordinates and Monte Carlo techniques that permit detailed modeling of the neutron transmission properties of the filtering crystals with very few approximations. Validation protocols based on neutron activation spectrometry measurements and rigorous least-square adjustment techniques show that the beam produces a neutron spectrum that has the anticipated level of thermal neutron flux and a somewhat higher than expected, but radio-biologically insignificant, epithermal neutron flux component. (authors)

  17. A Permanent-Magnet Microwave Ion Source for a Compact High-Yield Neutron Generator

    SciTech Connect

    Waldmann, Ole; Ludewigt, Bernhard

    2010-10-11

    We present recent work on the development of a microwave ion source that will be used in a high-yield compact neutron generator for active interrogation applications. The sealed tube generator will be capable of producing high neutron yields, 5x1011 n/s for D-T and ~;;1x1010 n/s for D-D reactions, while remaining transportable. We constructed a microwave ion source (2.45 GHz) with permanent magnets to provide the magnetic field strength of 87.5 mT necessary for satisfying the electron cyclotron resonance (ECR) condition. Microwave ion sources can produce high extracted beam currents at the low gas pressures required for sealed tube operation and at lower power levels than previously used RF-driven ion sources. A 100 mA deuterium/tritium beam will be extracted through a large slit (60x6 mm2) to spread the beam power over a larger target area. This paper describes the design of the permanent-magnet microwave ion source and discusses the impact of the magnetic field design on the source performance. The required equivalent proton beam current density of 40 mA/cm2 was extracted at a moderate microwave power of 400 W with an optimized magnetic field.

  18. CHINA SPALLATION NEUTRON SOURCE PROJECT: DESIGN ITERATIONS AND R AND D STATUS.

    SciTech Connect

    WEI,J.

    2006-09-21

    The China Spallation Neutron Source (CSNS) is an accelerator based high power project currently under preparation in China. The accelerator complex is based on an H{sup -} linear accelerator and a rapid cycling proton synchrotron. During the past year, the design of most accelerator systems went through major iterations, and initial research and developments were started on the prototyping of several key components. This paper summarizes major activities of the past year.

  19. Initial global 2-D shielding analysis for the Advanced Neutron Source core and reflector

    SciTech Connect

    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.

  20. ACHIEVING THE REQUIRED COOLANT FLOW DISTRIBUTION FOR THE ACCELERATOR PRODUCTION OF TRITIUM (APT) TUNGSTEN NEUTRON SOURCE

    SciTech Connect

    D. SIEBE; K. PASAMEHMETOGLU

    2000-11-01

    The Accelerator Production of Tritium neutron source consists of clad tungsten targets, which are concentric cylinders with a center rod. These targets are arranged in a matrix of tubes, producing a large number of parallel coolant paths. The coolant flow required to meet thermal-hydraulic design criteria varies with location. This paper describes the work performed to ensure an adequate coolant flow for each target for normal operation and residual heat-removal conditions.

  1. Loss-of-coolant accident analyses of the Advanced Neutron Source Reactor

    SciTech Connect

    Chen, N.C.J.; Yoder, G.L. ); Wendel, M.W. )

    1991-01-01

    Currently in the conceptual design stage, the Advanced Neutron Source Reactor (ANSR) will operate at a high heat flux, a high mass flux, an a high degree of coolant subcooling. Loss-of-coolant accident (LOCA) analyses using RELAP5 have been performed as part of an early evaluation of ANSR safety issues. This paper discusses the RELAP5 ANSR conceptual design system model and preliminary LOCA simulation results. Some previous studies were conducted for the preconceptual design. 12 refs., 7 figs.

  2. Current progress and future prospects of the VITA based neutron source.

    PubMed

    Aleynik, V; Bashkirtsev, A; Kanygin, V; Kasatov, D; Kuznetsov, A; Makarov, A; Schudlo, I; Sorokin, I; Taskaev, S; Tiunov, M

    2014-06-01

    At the BINP, a pilot accelerator based epithermal neutron source is now in use. Most recent investigations on the facility are related with studying the dark current, X-ray radiation measuring, optimization of H(-)-beam injection and new gas stripping target calibrating. The results of these studies, ways of providing stability to the accelerator are presented and discussed, as well as the ways of creating the therapeutic beam and strategies of applying the facility for clinical use. PMID:24369890

  3. A NEW SINGLE-CRYSTAL FILTERED THERMAL NEUTRON SOURCE FOR NEUTRON CAPTURE THERAPY RESEARCH AT THE UNIVERSITY OF MISSOURI

    SciTech Connect

    John D. Brockman; David W. Nigg; M. Frederick Hawthorne

    2008-09-01

    Parameter studies, design calculations and initial neutronic performance measurements have been completed for a new thermal neutron beamline to be used for neutron capture therapy cell and small-animal radiobiology studies at the University of Missouri Research Reactor. The beamline features the use of single-crystal silicon and bismuth sections for neutron filtering and for reduction of incident gamma radiation. The calculated and measured thermal neutron flux produced at the irradiation location is on the order of 9.5x108 neutrons/cm2-s, with a measured cadmium ratio (Au foils) of 105, indicating a well-thermalized spectrum.

  4. Parameters optimization in a fission-fusion system with a mirror machine based neutron source

    NASA Astrophysics Data System (ADS)

    Yurov, D. V.; Anikeev, A. V.; Bagryansky, P. A.; Brednikhin, S. A.; Frolov, S. A.; Lezhnin, S. I.; Prikhodko, V. V.

    2012-06-01

    Long-lived fission products utilization is a problem of high importance for the modern nuclear reactor technology. BINP jointly with NSI RAS develops a conceptual design of a hybrid sub-critical minor actinides burner with a neutron source based on the gas dynamic mirror machine (GDT) to resolve the stated task. A number of modelling tools was created to calculate the main parameters of the device. First of the codes, GENESYS, is a zero-dimensional code, designed for plasma dynamics numerical investigation in a GDT-based neutron source. The code contains a Monte-Carlo module for the determination of linear neutron emission intensity along the machine axis. Fuel blanket characteristics calculation was implemented by means of a static Monte-Carlo code NMC. Subcritical core, which has been previously analyzed by OECD-NEA, was used as a template for the fuel blanket of the modelled device. This article represents the codes used and recent results of the described system parameters optimization. Particularly, optimum emission zone length of the source and core multiplicity dependence on buffer zone thickness were defined.

  5. Design of an RFQ-Based Neutron Source for Cargo ContainerInterrogation

    SciTech Connect

    Staples, John W.; Hoff, M.D.; Kwan, J.W.; Li, D.; Ludewigt, B.A.; Ratti, A.; Virostek, S.P.; Wells, R.P.

    2006-08-01

    An RFQ-based neutron generator system is described that produces pulsed neutrons for the active screening of sea-land cargo containers for the detection of shielded special nuclear materials (SNM).A microwave-driven deuteron source is coupled to an electrostatic LEBT that injects a 40 mA D+ beam into a 6 MeV, 5.1 meter-long 200 MHz RFQ.The RFQ has a unique beam dynamics design and is capable of operating at duty factors of 5 to 10 percent accelerating a D+ time-averaged current of up to 1.5 mA at 5 percent duty factor, including species and transmission loss. The beam is transported through a specially-designed thin window into a 2.5-atmosphere deuterium gas target. A high-frequency dipole magnet is used to scan the beam over the long dimension of the 5by 35 cm target window. The source will deliver a neutron flux of 1 cdot107 n/(cm2s) to the center of an empty cargo container. Details of the ion source, LEBT, RFQ beam dynamics and gas target design are presented.

  6. Neutron calibration facility with an Am-Be source for pulse shape discrimination measurement of CsI(Tl) crystals

    E-print Network

    H. S. Lee; H. Bhang; J. H. Choi; S. Choi; I. S. Hahn; E. J. Jeon; H. W. Joo; W. G. Kang; G. B. Kim; H. J. Kim; K. W. Kim; S. C. Kim; S. K. Kim; Y. D. Kim; Y. H. Kim; J. H. Lee; J. K. Lee; D. S. Leonard; J. Li; S. S. Myung; S. L. Olsen; J. H. So

    2014-11-06

    We constructed a neutron calibration facility based on a 300-mCi Am-Be source in conjunction with a search for weakly interacting massive particle candidates for dark matter. The facility is used to study the response of CsI(Tl) crystals to nuclear recoils induced by neutrons from the Am-Be source and comparing them with the response to electron recoils produced by Compton scattering of 662-keV $\\gamma$-rays from a $^{137}$Cs source. The measured results on pulse shape discrimination (PSD) between nuclear- and electron-recoil events are quantified in terms of quality factors. A comparison with similar result from a neutron reactor demonstrate the feasibility of performing calibrations of PSD measurements using neutrons from a Am-Be source.

  7. Evaluation and validation of d Li cross section data for the IFMIF neutron source term simulation

    NASA Astrophysics Data System (ADS)

    Fischer, U.; Avrigeanu, M.; Pereslavtsev, P.; Simakov, S. P.; Schmuck, I.

    2007-08-01

    A completely new evaluation of the d + 6,7Li interaction cross sections up to 50 MeV has been performed applying a new methodology which takes into account compound nucleus reactions, pre-equilibrium processes, stripping and direct interactions. The evaluated d + 6,7Li cross section data were prepared in the laboratory frame, stored in standard ENDF-6 data format and processed by the NJOY code system. A series of benchmark calculations was performed with the McDeLicious code to test the new data evaluations against experimental thick and thin lithium target neutron yield data up to 40 MeV deuteron energy. It was shown that the new d + 6,7Li cross section data can well reproduce both the thick target neutron yields and differential neutron emission cross sections. Thus there is a clear improvement of the prediction accuracy for the IFMIF neutron source term simulation with the new d + 6,7Li cross section data evaluations.

  8. An ultraluminous X-ray source powered by an accreting neutron star

    NASA Astrophysics Data System (ADS)

    Bachetti, M.; Harrison, F. A.; Walton, D. J.; Grefenstette, B. W.; Chakrabarty, D.; Fürst, F.; Barret, D.; Beloborodov, A.; Boggs, S. E.; Christensen, F. E.; Craig, W. W.; Fabian, A. C.; Hailey, C. J.; Hornschemeier, A.; Kaspi, V.; Kulkarni, S. R.; Maccarone, T.; Miller, J. M.; Rana, V.; Stern, D.; Tendulkar, S. P.; Tomsick, J.; Webb, N. A.; Zhang, W. W.

    2014-10-01

    The majority of ultraluminous X-ray sources are point sources that are spatially offset from the nuclei of nearby galaxies and whose X-ray luminosities exceed the theoretical maximum for spherical infall (the Eddington limit) onto stellar-mass black holes. Their X-ray luminosities in the 0.5-10 kiloelectronvolt energy band range from 1039 to 1041 ergs per second. Because higher masses imply less extreme ratios of the luminosity to the isotropic Eddington limit, theoretical models have focused on black hole rather than neutron star systems. The most challenging sources to explain are those at the luminous end of the range (more than 1040 ergs per second), which require black hole masses of 50-100 times the solar value or significant departures from the standard thin disk accretion that powers bright Galactic X-ray binaries, or both. Here we report broadband X-ray observations of the nuclear region of the galaxy M82 that reveal pulsations with an average period of 1.37 seconds and a 2.5-day sinusoidal modulation. The pulsations result from the rotation of a magnetized neutron star, and the modulation arises from its binary orbit. The pulsed flux alone corresponds to an X-ray luminosity in the 3-30 kiloelectronvolt range of 4.9 × 1039 ergs per second. The pulsating source is spatially coincident with a variable source that can reach an X-ray luminosity in the 0.3-10 kiloelectronvolt range of 1.8 × 1040 ergs per second. This association implies a luminosity of about 100 times the Eddington limit for a 1.4-solar-mass object, or more than ten times brighter than any known accreting pulsar. This implies that neutron stars may not be rare in the ultraluminous X-ray population, and it challenges physical models for the accretion of matter onto magnetized compact objects.

  9. An ultraluminous X-ray source powered by an accreting neutron star.

    PubMed

    Bachetti, M; Harrison, F A; Walton, D J; Grefenstette, B W; Chakrabarty, D; Fürst, F; Barret, D; Beloborodov, A; Boggs, S E; Christensen, F E; Craig, W W; Fabian, A C; Hailey, C J; Hornschemeier, A; Kaspi, V; Kulkarni, S R; Maccarone, T; Miller, J M; Rana, V; Stern, D; Tendulkar, S P; Tomsick, J; Webb, N A; Zhang, W W

    2014-10-01

    The majority of ultraluminous X-ray sources are point sources that are spatially offset from the nuclei of nearby galaxies and whose X-ray luminosities exceed the theoretical maximum for spherical infall (the Eddington limit) onto stellar-mass black holes. Their X-ray luminosities in the 0.5-10 kiloelectronvolt energy band range from 10(39) to 10(41) ergs per second. Because higher masses imply less extreme ratios of the luminosity to the isotropic Eddington limit, theoretical models have focused on black hole rather than neutron star systems. The most challenging sources to explain are those at the luminous end of the range (more than 10(40) ergs per second), which require black hole masses of 50-100 times the solar value or significant departures from the standard thin disk accretion that powers bright Galactic X-ray binaries, or both. Here we report broadband X-ray observations of the nuclear region of the galaxy M82 that reveal pulsations with an average period of 1.37 seconds and a 2.5-day sinusoidal modulation. The pulsations result from the rotation of a magnetized neutron star, and the modulation arises from its binary orbit. The pulsed flux alone corresponds to an X-ray luminosity in the 3-30 kiloelectronvolt range of 4.9 × 10(39) ergs per second. The pulsating source is spatially coincident with a variable source that can reach an X-ray luminosity in the 0.3-10 kiloelectronvolt range of 1.8 × 10(40) ergs per second. This association implies a luminosity of about 100 times the Eddington limit for a 1.4-solar-mass object, or more than ten times brighter than any known accreting pulsar. This implies that neutron stars may not be rare in the ultraluminous X-ray population, and it challenges physical models for the accretion of matter onto magnetized compact objects. PMID:25297433

  10. An Ultraluminous X-Ray Source Powered by an Accreting Neutron Star

    NASA Technical Reports Server (NTRS)

    Bachetti, M.; Harrison, F. A.; Walton, D. J.; Grefenstette, B. W.; Chakrabarty, D.; Furst, F.; Barret, D.; Beloborodov, A.; Boggs, S. E.; Christensen, F. E.; Hornschemeier, A.; Zhang, William W.

    2014-01-01

    The majority of ultraluminous X-ray sources are point sources that are spatially offset fromthe nuclei of nearby galaxies andwhoseX-ray luminosities exceed the theoretical maximum for spherical infall (the Eddington limit) onto stellar-mass black holes. Their X-ray luminosities in the 0.5-10 kiloelectronvolt energy band range from 10(exp. 39) to 10(exp. 41) ergs per second cube. Because higher masses imply less extreme ratios of the luminosity to the isotropic Eddington limit, theoretical models have focused on black hole rather than neutron star systems. Themost challenging sources to explain are those at the luminous end of the range (more than 10(exp. 40) ergs per second),which require black hole masses of 50-100 times the solar value or significant departures from the standard thin disk accretion that powers bright Galactic X-ray binaries, or both. Here we report broadband X-ray observations of the nuclear region of the galaxy M82 that reveal pulsations with an average period of 1.37 seconds and a 2.5-day sinusoidalmodulation. The pulsations result from the rotation of amagnetized neutron star, and the modulation arises fromits binary orbit.The pulsed flux alone corresponds to an X-ray luminosity inthe 3-30 kiloelectronvolt range of 4.9 x 10(exp. 39) ergs per second. The pulsating source is spatially coincident with a variable source that can reach an X-ray luminosity in the 0.3-10 kiloelectronvolt range of 1.8 x 10(exp. 40) ergs per second1.This association implies a luminosity of about 100 times the Eddington limit for a 1.4-solar-mass object, or more than ten times brighter than any known accreting pulsar. This implies that neutron stars may not be rare in the ultraluminous X-ray population, and it challenges physical models for the accretion of matter onto magnetized compact objects.

  11. Surviving to tell the tale : Argonne's Intense Pulsed Neutron Source from an ecosystem perspective.

    SciTech Connect

    Westfall, C.; Office of The Director

    2010-07-01

    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.

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

    SciTech Connect

    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.

  13. Performance of the prototype LANL solid deuterium ultra-cold neutron source

    NASA Astrophysics Data System (ADS)

    Hill, Roger E.; Anaya, J. M.; Bowles, T. J.; Greene, G. L.; Hogan, G.; Lamoreaux, S.; Marek, L.; Mortenson, R.; Morris, C. L.; Saunders, A.; Seestrom, S. J.; Teasdale, W.; Hoedl, S.; Liu, C.-Y.; Smith, D. A.; Young, A.; Filippone, B. W.; Hua, J.; Ito, T.; Pasyuk, E.; Geltenbort, P.; Garcia, A.; Fujikawa, B.; Baessler, S.; Serebrov, A.

    2000-02-01

    A prototype of a solid deuterium (SD 2) source of Ultra-Cold Neutrons (UCN) is currently being tested at LANSCE. The source is contained within an assembly consisting of a 4 K polyethylene moderator surrounded by a 77 K beryllium flux trap in which is embedded a spallation target. Time-of-flight measurements have been made of the cold neutron spectrum emerging directly from the flux trap assembly. A comparison is presented of these measurements with results of Monte Carlo (LAHET/MCNP) calculations of the cold neutron fluxes produced in the prototype assembly by a beam of 800 MeV protons incident on the tungsten target. A UCN detector was coupled to the assembly through a guide system with a critical velocity of 8 m/s ( 58Ni). The rates and time-of-flight data from this detector are compared with calculated values. Measurements of UCN production as a function of SD 2 volume (thickness) are compared with predicted values. The dependence of UCN production on SD 2 temperature and proton beam intensity are also presented.

  14. Accelerating Data Acquisition, Reduction, and Analysis at the Spallation Neutron Source

    SciTech Connect

    Campbell, Stuart I; Kohl, James Arthur; Granroth, Garrett E; Miller, Ross G; Doucet, Mathieu; Stansberry, Dale V; Proffen, Thomas E; Taylor, Russell J; Dillow, David

    2014-01-01

    ORNL operates the world's brightest neutron source, the Spallation Neutron Source (SNS). Funded by the US DOE Office of Basic Energy Science, this national user facility hosts hundreds of scientists from around the world, providing a platform to enable break-through research in materials science, sustainable energy, and basic science. While the SNS provides scientists with advanced experimental instruments, the deluge of data generated from these instruments represents both a big data challenge and a big data opportunity. For example, instruments at the SNS can now generate multiple millions of neutron events per second providing unprecedented experiment fidelity but leaving the user with a dataset that cannot be processed and analyzed in a timely fashion using legacy techniques. To address this big data challenge, ORNL has developed a near real-time streaming data reduction and analysis infrastructure. The Accelerating Data Acquisition, Reduction, and Analysis (ADARA) system provides a live streaming data infrastructure based on a high-performance publish subscribe system, in situ data reduction, visualization, and analysis tools, and integration with a high-performance computing and data storage infrastructure. ADARA allows users of the SNS instruments to analyze their experiment as it is run and make changes to the experiment in real-time and visualize the results of these changes. In this paper we describe ADARA, provide a high-level architectural overview of the system, and present a set of use-cases and real-world demonstrations of the technology.

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

    SciTech Connect

    Marzec, B.

    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.

  16. ANSL-V: ENDF/B-V based multigroup cross-section libraries for Advanced Neutron Source (ANS) reactor studies

    SciTech Connect

    Ford, W.E. III; Arwood, J.W.; Greene, N.M.; Petrie, L.M.; Primm, R.T. III; Waddell, M.W.; Webster, C.C.; Westfall, R.M.; Wright, R.Q.

    1987-01-01

    Multigroup P3 neutron, P0-P3 secondary gamma ray production (SGRP), and P6 gamma ray interaction (GRI) cross section libraries have been generated to support design work on the Advanced Neutron Source (ANS) reactor. The libraries, designated ANSL-V (Advanced Neutron Source Cross-Section Libraries), are data bases in a format suitable for subsequent generation of problem dependent cross sections. The ANSL-V libraries are available on magnetic tape from the Radiation Shielding Information Center at Oak Ridge National Laboratory.

  17. Dose Measurements of Bremsstrahlung-Produced Neutrons at the Advanced Photon Source

    SciTech Connect

    Job, P.K.; Pisharody, M.; Semones, E.

    1998-08-01

    Bremsstrahlung is generated in the storage rings of the synchrotron radiation facilities by the radiative interaction of the circulating particle beam with both the residual gas molecules and storage ring components. These bremsstrahlung photons, having an energy range of zero to the maximum energy of the particle beam, interact with beamline components like beam stops and collimators generating photoneutrons of varying energies. There are three main processes by which photoneutrons may be produced by the high energy bremsstrahlung photons: giant nuclear dipole resonance and decay (10 MeV < E{sub {gamma}} < 30 MeV), quasi-deuteron production and decay (50 MeV < E{sub {gamma}} < 300 MeV), and intranuclear cascade and evaporation (E{sub {gamma}} > 140 MeV). The giant resonance neutrons are emitted almost isotropically and have an average energy of about 2 MeV. High energy neutrons (E > 10 MeV) emitted from the quasi-deuteron decay and intranuclear cascade are peaked in the forward direction. At the Advanced Photon Source (APS), where bremsstrahlung energy can be as high as 7 GeV, production of photoneutrons in varying yields is possible from all of the above three processes. The bremsstrahlung produced along a typical 15.38-m straight path of the insertion device (ID) beamline of the APS has been measured and analyzed in previous studies. High-Z materials constituting the beamline components, such as collimators and beam stops, can produce photoneutrons upon interaction with these bremsstrahlung photons. The 1/E nature of the bremsstrahlung spectrum and the fact that the photoneutron production cross section is comparatively larger in the energy region 10 MeV < E{sub {gamma}} < 30 MeV, results in the giant resonance interaction being the dominant mechanism that generates photoneutrons at the APS. Such neutron flux in the vicinities of the first optics enclosures (FOEs) of ID beamlines is important, from the point of view of radiation protection of the personnel. Only a few of such neutron flux measurements were conducted at high photon energies. Monte Carlo codes and analytical formulas are used to calculate the differential photon track length in targets. Together with the known photoneutron cross sections, the neutron yields are then determined as a function of incident electron energy. Neutron fluence calculated from these yields assumes isotropic emission of neutrons from a point source target. Because neutron transport is not handled in most of these studies, possible neutron interactions inside the target are not accounted for in calculating the energy and intensity outside the target. There is also the uncertainty of photoneutron production cross section at higher energies. A simultaneous measurement of bremsstrahlung and corresponding photoneutron production will provide photoneutron dose rates as a function of bremsstrahlung energy or power. Along with our already existing bremsstrahlung spectrum measurement expertise, we conducted simultaneous photoneutron dose measurements at the APS from thick targets of Fe, Cu, W, and Pb that are placed in the bremsstrahlung beam inside the FOE of the insertion device beamlines. An Andersson-Braun (AB) remmeter that houses a BF{sub 3} detector, as well as a very sensitive pressurized {sup 3}He detector, is used for neutron dose measurements. The dose equivalent rates, normalized to bremsstrahlung power, beam current, and storage ring vacuum, are measured for various targets. This report details the experimental setup, data acquisition system, calibration procedures, analysis of the data and the results of the measurements.

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

    SciTech Connect

    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.

  19. Shielding analysis and design of the KIPT experimental neutron source facility of Ukraine.

    SciTech Connect

    Zhong, Z.; Gohar, M. Y. A.; Naberezhnev, D.; Duo, J.; Nuclear Engineering Division

    2008-10-31

    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 based on the use of an electron accelerator driven subcritical (ADS) facility [1]. The facility uses the existing electron accelerators of KIPT in Ukraine. The neutron source of the sub-critical assembly is generated from the interaction of 100 KW electron beam with a natural uranium target. The electron beam has a uniform spatial distribution and the electron energy in the range of 100 to 200 MeV, [2]. The main functions of the facility are the production of medical isotopes and the support of the Ukraine nuclear power industry. Reactor physics experiments and material performance characterization will also be carried out. The subcritical assembly is driven by neutrons generated by the electron beam interactions with the target material. A fraction of these neutrons has an energy above 50 MeV generated through the photo nuclear interactions. This neutron fraction is very small and it has an insignificant contribution to the subcritical assembly performance. However, these high energy neutrons are difficult to shield and they can be slowed down only through the inelastic scattering with heavy isotopes. Therefore the shielding design of this facility is more challenging relative to fission reactors. To attenuate these high energy neutrons, heavy metals (tungsten, iron, etc.) should be used. To reduce the construction cost, heavy concrete with 4.8 g/cm{sup 3} density is selected as a shielding material. The iron weight fraction in this concrete is about 0.6. The shape and thickness of the heavy concrete shield are defined to reduce the biological dose equivalent outside the shield to an acceptable level during operation. At the same time, special attention was give to reduce the total shield mass to reduce the construction cost. The shield design is configured to maintain the biological dose equivalent during operation {le} 0.5 mrem/h inside the subcritical hall, which is five times less than the allowable dose for working forty hours per week for 50 weeks per year. This study analyzed and designed the thickness and the shape of the radial and top shields of the neutron source based on the biological dose equivalent requirements inside the subcritical hall during operation. The Monte Carlo code MCNPX is selected because of its capabilities for transporting electrons, photons, and neutrons. Mesh based weight windows variance reduction technique is utilized to estimate the biological dose outside the shield with good statistics. A significant effort dedicated to the accurate prediction of the biological dose equivalent outside the shield boundary as a function of the shield thickness without geometrical approximations or material homogenization. The building wall was designed with ordinary concrete to reduce the biological dose equivalent to the public with a safety factor in the range of 5 to 20.

  20. Production and Characterization of 228Th Calibration Sources with Low Neutron Emission for GERDA

    E-print Network

    Baudis, Laura; Carconi, Pierluigi; Cattadori, Carla Maria; De Felice, Pierino; Eberhardt, Klaus; Eichler, Robert; Petrucci, Andrea; Tarka, Michal; Walter, Manuel

    2015-01-01

    The GERDA experiment at the Laboratori Nazionali del Gran Sasso (LNGS) searches for the neutrinoless double beta decay of 76-Ge. In view of the GERDA Phase II data collection, four new 228-Th radioactive sources for the calibration of the germanium detectors enriched in 76-Ge have been produced with a new technique, leading to a reduced neutron flux from ( alpha; n ) reactions. The gamma activities of the sources were determined with a total uncertainty of 4 percent using an ultra-low background HPGe detector operated underground at LNGS. The emitted neutron flux was determined using a low background LiI(Eu) detector and a 3-He counter at LNGS. In both cases, a reduction of about one order of magnitude with respect to commercially available 228-Th sources was obtained. Additionally, a specific leak test with a sensitivity to leaks down to 10 mBq was developed to investigate the tightness of the stainless steel capsules housing the sources after their use in cryogenic environment.

  1. Geometrical shape optimization of a cold neutron source using artificial intelligence strategies

    SciTech Connect

    Azmy, Y.Y.

    1989-01-01

    A new approach is developed for optimizing the geometrical shape of a cold neutron source to maximize its cold neutron outward leakage. An analogy is drawn between the shape optimization problem and a state space search, which is the fundamental problem in Artificial Intelligence applications. The new optimization concept is implemented in the computer code DAIT in which the physical model is represented by a two group, r-z geometry nodal diffusion method, and the state space search is conducted via the Nearest Neighbor algorithm. The accuracy of the nodal diffusion method solution is established on meshes of interest, and is shown to behave qualitatively the same as transport theory solutions. The dependence of the optimum shape and its value on several physical and search parameters is examined via numerical experimentation. 10 refs., 6 figs., 2 tabs.

  2. Oak Ridge Reservation site evaluation report for the Advanced Neutron Source

    SciTech Connect

    Sigmon, B.; Heitzman, A.C. Jr.; Morrissey, J. )

    1990-03-01

    The Advanced Neutron Source (ANS) is a research reactor that is the US Department of Energy (DOE) plans to build for initial service late in this century. The primary purpose of the ANS is to provide a useable neutron flux for scattering experiments 5 to 10 times as a high as that generated by any existing research reactor, secondary purposes include production of a variety of transuranic and other isotopes and irradiation of materials. The ANS is proposed to be located on the DOE Oak Ridge Reservation (ORR) at Oak Ridge, Tennessee, and operated by the Oak Ridge National Laboratory (ORNL). This report documents the evaluation of alternative sites on the ORR and the selection of a site for the ANS.

  3. OscSNS: Precision Neutrino Measurements at the Spallation Neutron Source

    E-print Network

    Heather Ray; for the OscSNS Collaboration

    2008-10-17

    The Spallation Neutron Source (SNS), located at Oak Ridge Laboratory in the United States, will be coming online over the next few years. In addition to producing fluxes of high-intensity neutrons, the interaction of the proton beam with the liquid mercury target produces copious pions. The pi+ and subsequent mu+ decay at rest, providing a neutrino beam comprising numu, nue, and anti-numu components. This neutrino beam is ideal for high-precision neutrino experiments. OscSNS is a proposed multi-purpose experiment that will perform a search for light sterile neutrinos, search for beyond the Standard Model interactions using neutrino oscillations, and provide tests of Standard Model predictions through world-record precision neutrino cross section measurements. OscSNS plans to submit a full proposal for funding in 2009.

  4. EXPLORATION OF BEAM FAULT SCENARIOS FOR THE SPALLATION NEUTRON SOURCE TARGET.

    SciTech Connect

    HENDERSON,S.RAPARIA,D.FEDOTOV,A.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 ensure adequate lifetime of the target system components, requirements on several beam parameters must be maintained. A series of error studies was performed to explore credible fault scenarios which can potentially violate the various beam-on-target parameters. The response of the beam-on-target parameters to errors associated with the phase-space painting process in the ring and field setpoint errors in all the ring-to-target beam transport line elements were explored and will be presented. The plan for ensuring beam-on-target parameters will also be described.

  5. Transmutation of nuclear waste with a low-aspect-ratio tokamak neutron source

    NASA Astrophysics Data System (ADS)

    Hong, Bong Guen; Moon, Se Youn

    2014-10-01

    The transmutation characteristics of transuranics (TRUs) in a transmutation reactor based on a LAR (Low-aspect-ratio) tokamak as a neutron source are investigated. The optimum radial build of a transmutation reactor is found by using a coupled analysis of the tokamak systems and the neutron transport. The dependences of the transmutation characteristics on the aspect ratio A in the range of 1.5 to 2.5 and on the fusion power in the range of 150 to 500 MW are investigated. An equilibrium fuel cycle is developed for effective transmutation, and show that with one unit of the transmutation reactor based on the LAR tokamak producing fusion power in the range of a few hundred MWs, up to 3 PWRs (1.0 GWe capacity) can be supported with a burn-up fraction larger than 50%.

  6. Laser-driven ?-ray, positron, and neutron source from ultra-intense laser-matter interactions

    NASA Astrophysics Data System (ADS)

    Nakamura, Tatsufumi; Hayakawa, Takehito

    2015-08-01

    In ultra-intense laser-matter interactions, ?-rays are effectively generated via the radiation reaction effect. Since a significant fraction of the laser energy is converted into ?-rays, understanding of the energy transport inside of the target is important. We have developed a Particle-in-Cell code which includes generation of the ?-rays, their energy transport, and photo-nuclear reactions. Using the code, we have investigated the characteristics of the quantum beams generated by the transport of the laser-driven ?-rays. It is shown that collimated, mono-energetic positron beams with hundreds of MeV are generated by using thick targets. Neutron beams are also effectively generated by using beryllium targets via photo-nuclear reactions. These lead to the proposal of quantum beam sources of ?-rays, positrons, and neutrons with distinctive characters, which are selectively generated by choosing target conditions.

  7. A comparison of four direct geometry time-of-flight spectrometers at the Spallation Neutron Source

    SciTech Connect

    Stone, M. B.; Abernathy, D. L.; Ehlers, G.; Garlea, O.; Podlesnyak, A.; Winn, B.; Niedziela, J. L.; DeBeer-Schmitt, L.; Graves-Brook, M.; Granroth, G. E.; Kolesnikov, A. I.

    2014-04-15

    The Spallation Neutron Source at Oak Ridge National Laboratory now hosts four direct geometry time-of-flight chopper spectrometers. These instruments cover a range of wave-vector and energy transfer space with varying degrees of neutron flux and resolution. The regions of reciprocal and energy space available to measure at these instruments are not exclusive and overlap significantly. We present a direct comparison of the capabilities of this instrumentation, conducted by data mining the instrument usage histories, and specific scanning regimes. In addition, one of the common science missions for these instruments is the study of magnetic excitations in condensed matter systems. We have measured the powder averaged spin wave spectra in one particular sample using each of these instruments, and use these data in our comparisons.

  8. A comparison of four direct geometry time-of-flight spectrometers at the Spallation Neutron Source

    SciTech Connect

    Stone, Matthew B; Niedziela, Jennifer L; Abernathy, Douglas L; Debeer-Schmitt, Lisa M; Garlea, Vasile O; Granroth, Garrett E; Graves-Brook, Melissa K; Ehlers, Georg; Kolesnikov, Alexander I; Podlesnyak, Andrey A; Winn, Barry L

    2014-04-01

    The Spallation Neutron Source at Oak Ridge National Laboratory now hosts four direct geometry time-of-flight chopper spectrometers. These instruments cover a range of wave vector and energy transfer space with varying degrees of neutron flux and resolution. The regions of reciprocal and energy space available to measure at these instruments is not exclusive and overlaps significantly. We present a direct comparison of the capabilities of this instrumentation, conducted by data mining the instrument usage histories, and specific scanning regimes. In addition, one of the common science missions for these instruments is the study of magnetic excitations in condensed matter systems. We have measured the powder averaged spin wave spectra in one particular sample using each of these instruments, and use these data in our comparisons.

  9. Modeling & analysis of core debris recriticality during hypothetical severe accidents in the Advanced Neutron Source Reactor

    SciTech Connect

    Kim, S.H.; Georgevich, V.; Simpson, D.B.; Slater, C.O.; Taleyarkhan, R.P.

    1992-10-01

    This paper discusses salient aspects of severe-accident-related recriticality modeling and analysis in the Advanced Neutron Source (ANS) reactor. The development of an analytical capability using the KEN05A-SCALE system is described including evaluation of suitable nuclear cross-section sets to account for the effects of system geometry, mixture temperature, material dispersion and other thermal-hydraulic conditions. Benchmarking and validation efforts conducted with KEN05-SCALE and other neutronic codes against critical experiment data are described. Potential deviations and biases resulting from use of the 16-group Hansen-Roach library are shown. A comprehensive test matrix of calculations to evaluate the threat of a criticality event in the ANS is described. Strong dependencies on geometry, material constituents, and thermal-hydraulic conditions are described. The introduction of designed mitigative features are described.

  10. Comparison of Measured and Calculated Mixed Neutron and Gamma Fields in Iron and Water Benchmark Assemblies Driven by CF-252 Neutron Source

    NASA Astrophysics Data System (ADS)

    Jánský, B.; Novák, E.; Turzík, Z.; Kyncl, J.; Cvachovec, F.; Kluso?, J.; Trykov, L. A.; Volkov, V. S.; ?uda, P.

    2003-06-01

    Iron and water are two main shielding materials used in nuclear reactors, therefore these two materials have been studied from the point of view of neutron and gamma radiation transport. WWER-440 and WWER-1000 mock-up arrangements have been assembled at the LR-0 experimental reactor in NRI Rez plc before with the purpose to study neutron and gamma flux impinging the reactor pressure vessel. In parallel, the neutron and gamma radiation transport have been studied on the simplest spherical geometry, i.e. on benchmark assemblies located in the LR-0 reactor hall. Iron spheres of 30, 50 and 100 cm in diameter and water spheres of 30 and 50 cm in diameter were used for that benchmark. A Cf-252 neutron source with emission of 3×108 n/s was each time positioned in the centre of a sphere. The leakage neutron and gamma spectra were measured by independent neutron and gamma spectrometers of the different laboratories. Neutron spectra were measured by proportional counters filled with hydrogen and by scintillation detectors of stilbene type in the energy range of 0.01-20 MeV. Gamma spectra were measured by detectors of stilbene, germanium and silicon type, in the energy range of 0.4-12 MeV. All the important parameters of the experimental assemblies, necessary for the computation (geometry, material composition, neutron source input spectra), were summarised. The calculations of neutron and gamma spectra were performed with the MCNP code using the ENDF/B-VI data library. The intercomparison of measured and calculated data has been done. In view of the good reproducibility of mixed neutron and gamma (n,g) field parameters and exact data setting for calculation the experimental assembly can be used for the following purposes:. - testing of spectrometry and dosimetry equipment in mixed n,g fields. - testing of calculation methods and small-group data libraries for Fe and H2O. In addition, upon a careful analysis of the obtained results, the neutron spectrum of the iron sphere with a diameter of 50 cm is proposed for an international standard of the moderated neutron field.

  11. A Strong Shallow Heat Source in the Accreting Neutron Star MAXI J0556-332

    NASA Astrophysics Data System (ADS)

    Deibel, Alex; Cumming, Andrew; Brown, Edward F.; Page, Dany

    2015-08-01

    An accretion outburst in an X-ray transient deposits material onto the neutron star primary; this accumulation of matter induces reactions in the neutron star’s crust. During the accretion outburst these reactions heat the crust out of thermal equilibrium with the core. When accretion halts, the crust cools to its long-term equilibrium temperature on observable timescales. Here we examine the accreting neutron star transient MAXI J0556-332, which is the hottest transient, at the start of quiescence, observed to date. Models of the quiescent light curve require a large deposition of heat in the shallow outer crust from an unknown source. The additional heat injected is ?4-10 MeV per accreted nucleon; when the observed decline in accretion rate at the end of the outburst is accounted for, the required heating increases to ?6-16 MeV. This shallow heating is still required to fit the light curve even after taking into account a second accretion episode, uncertainties in distance, and different surface gravities. The amount of shallow heating is larger than that inferred for other neutron star transients and is larger than can be supplied by nuclear reactions or compositionally driven convection; but it is consistent with stored mechanical energy in the accretion disk. The high crust temperature ({T}b? {10}9 {{K}}) makes its cooling behavior in quiescence largely independent of the crust composition and envelope properties, so that future observations will probe the gravity of the source. Fits to the light curve disfavor the presence of Urca cooling pairs in the crust.

  12. Background Studies for an Experimental Neutrino Program at the Spallation Neutron Source for the COHERENT Collaboration

    NASA Astrophysics Data System (ADS)

    Newby, Jason; Coherent Collaboration

    2014-09-01

    The Spallation Neutron Source at the Oak Ridge National Laboratory is a copious producer of neutrinos with multiple flavors, energies and timing structure ideally suited to conduct a broad range of neutrino measurements. Toward this goal of performing neutrino experiments, the recently formed COHERENT collaboration is measuring fast neutron backgrounds within the SNS target building and modeling multiple relevant detector technologies. While the collaboration has identified a rich multi-phased multi-nucleus experimental program, preparations are underway for a near-term observation of coherent elastic neutrino-nuclear scattering with at least one of three maturing detector development efforts within the collaboration. We will outline the proposed experimental program and present the results of our backgrounds measurement campaign and their implications for the feasibility and optimization for the neutrino experimental program. The Spallation Neutron Source at the Oak Ridge National Laboratory is a copious producer of neutrinos with multiple flavors, energies and timing structure ideally suited to conduct a broad range of neutrino measurements. Toward this goal of performing neutrino experiments, the recently formed COHERENT collaboration is measuring fast neutron backgrounds within the SNS target building and modeling multiple relevant detector technologies. While the collaboration has identified a rich multi-phased multi-nucleus experimental program, preparations are underway for a near-term observation of coherent elastic neutrino-nuclear scattering with at least one of three maturing detector development efforts within the collaboration. We will outline the proposed experimental program and present the results of our backgrounds measurement campaign and their implications for the feasibility and optimization for the neutrino experimental program. Research sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U. S. Department of Energy.

  13. Recovery of {sup 241}Am/Be neutron sources, Wooster, Ohio

    SciTech Connect

    Tompkins, J.A.; Wannigman, D.; Hatler, V.

    1998-07-01

    In August 1997, the Nuclear Regulatory Commission (NRC) submitted to the US Department of Energy (DOE) a partial list of licensed radioactive sealed sources to be recovered under a pilot project initiating Radioactive Source Recovery Program (RSRP) operations. The first of the pilot project recoveries was scheduled for September 1997 at Eastern Well Surveys in Wooster, Ohio, a company with five unwanted sealed sources on the NRC list. The sources were neutron emitters, each containing {sup 241}Am/Be with activities ranging from 2.49 to 3.0 Ci. A prior radiological survey had established that one of these sources, a Gulf Nuclear Model 71-1 containing 3 Ci of {sup 241}Am, was contaminated with {sup 241}Am and might be leaking. The other four sources were obsolete and could no longer be used by Eastern Well Surveys for their intended application in well-logging applications due to NRC decertification of these sources. All of the sources exceeded the limits established for Class C waste under 10 CFR 61.55 and, as a result, are the ultimate responsibility of the DOE under the provisions of PL 99-240. This report describes the cooperative effort between the DOE and NRC to recover the sources and transport them to Los Alamos National Laboratory (LANL) for deactivation under the RSRP. This operation alleviated any potential risk to the public health and safety from the site which might result from the leaking neutron sources or the potential mismanagement of unwanted sources. The on-site recovery occurred on September 23, 1997, and was performed by personnel from LANL and its contractor and was observed by staff from the Region III office of the NRC. All aspects of the recovery were successfully accomplished, and the sources were received at LANL on September 29, 1997. Experience gained during this operation will be used to formulate operational poilicies and procedures which will contribute to the eventual routine recovery operations of a full-scale RSRP.

  14. Plasma emission spectroscopy for operating and developing the Spallation Neutron Source (SNS) H(-) ion sources.

    PubMed

    Han, B X; Welton, R F; Murray, S N; Pennisi, T R; Santana, M; Stockli, M P

    2014-02-01

    A RF-driven, Cs-enhanced H(-) ion source feeds the SNS accelerator with a high current (typically >50 mA), ?1.0 ms pulsed beam at 60 Hz. To achieve the persistent high current beam for several weeks long service cycles, each newly installed ion source undergoes a rigorous conditioning and cesiation processes. Plasma conditioning outgases the system and sputter-cleans the ion conversion surfaces. A cesiation process immediately following the plasma conditioning releases Cs to provide coverage on the ion conversion surfaces. The effectiveness of the ion source conditioning and cesiation is monitored with plasma emission spectroscopy using a high-sensitivity optical spectrometer. Plasma emission spectroscopy is also used to provide a means for diagnosing and confirming a failure of the insulating coating of the ion source RF antenna which is immersed in the plasma. Emissions of composition elements of the antenna coating material, Na emission being the most significant, drastically elevate to signal a failure when it happens. Plasma spectra of the developmental ion source with an AlN (aluminum nitrite) chamber and an external RF antenna are also briefly discussed. PMID:24593570

  15. A high intensity slow positron facility for the Advanced Neutron Source

    SciTech Connect

    Hulett, L.D. Jr.; Eberle, C.C.

    1994-07-01

    A slow positron spectroscopy facility, based on {sup 64}Cu activation, has been designed for incorporation in the Advanced Neutron Source (ANS). The ANS is a reactor-based research center planned for construction at Oak Ridge, Tennessee, USA. Multiple sources of slow positron beams will be available. One-half mm diameter, copper-coated aluminum microspheres will be activated and transported to a positron spectroscopy building, where they will be dispersed over the surfaces of horizontal pans, 0.1 m{sup 2} in area, located in source chambers. Fast positions from the pans will be intercepted by cylinders coated inside with inert gas moderators. Yields will approach 10{sup 12} positrons per second before brightness enhancement. Beams will be transported to multiple experiment stations, which will include a 50 meter diameter, 20-detector angular correlation of annihilation radiation (ACAR) spectrometer, and other equipment for materials analysis and fundamental science.

  16. A high intensity slow positron facility for the advanced neutron source

    SciTech Connect

    Hulett, L.D. Jr.; Eberle, C.C.

    1994-12-31

    A slow positron spectroscopy facility, based on {sup 64}Cu activation, has been designed for incorporation in the Advanced Neutron Source (ANS). The ANS is a reactor-based research center planned for construction at Oak Ridge, Tennessee, U.S.A. Multiple sources of slow positron beams will be available. One-half mm diameter, copper-coated aluminum microspheres will be activated and transported to a positron spectroscopy building, where they will be dispersed over the surfaces of horizontal pans, 0.1 m{sup 2} in area, located in source chambers. Fast positrons from the pans will be intercepted by cylinders coated inside with inert gas moderators. Yields will approach 10{sup 12} positrons per second before brightness enhancement. Beams will be transported to multiple experiment stations, which will include a 50 meter diameter, 20-detector angular correlation of annihilation radiation (ACAR) spectrometer, and other equipment for materials analysis and fundamental science.

  17. Experimental characterization of the Advanced Liquid Hydrogen Cold Neutron Source spectrum of the NBSR reactor at the NIST Center for Neutron Research

    NASA Astrophysics Data System (ADS)

    Cook, J. C.; Barker, J. G.; Rowe, J. M.; Williams, R. E.; Gagnon, C.; Lindstrom, R. M.; Ibberson, R. M.; Neumann, D. A.

    2015-08-01

    The recent expansion of the National Institute of Standards and Technology (NIST) Center for Neutron Research facility has offered a rare opportunity to perform an accurate measurement of the cold neutron spectrum at the exit of a newly-installed neutron guide. Using a combination of a neutron time-of-flight measurement, a gold foil activation measurement, and Monte Carlo simulation of the neutron guide transmission, we obtain the most reliable experimental characterization of the Advanced Liquid Hydrogen Cold Neutron Source brightness to date. Time-of-flight measurements were performed at three distinct fuel burnup intervals, including one immediately following reactor startup. Prior to the latter measurement, the hydrogen was maintained in a liquefied state for an extended period in an attempt to observe an initial radiation-induced increase of the ortho (o)-hydrogen fraction. Since para (p)-hydrogen has a small scattering cross-section for neutron energies below 15 meV (neutron wavelengths greater than about 2.3 Å), changes in the o- p hydrogen ratio and in the void distribution in the boiling hydrogen influence the spectral distribution. The nature of such changes is simulated with a continuous-energy, Monte Carlo radiation-transport code using 20 K o and p hydrogen scattering kernels and an estimated hydrogen density distribution derived from an analysis of localized heat loads. A comparison of the transport calculations with the mean brightness function resulting from the three measurements suggests an overall o- p ratio of about 17.5(±1) % o- 82.5% p for neutron energies<15 meV, a significantly lower ortho concentration than previously assumed.

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

    NASA Astrophysics Data System (ADS)

    Stefanik, Milan; Bem, Pavel; Gotz, Miloslav; Katovsky, Karel; Majerle, Mitja; Novak, Jan; Simeckova, Eva

    2014-11-01

    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 9.2 ?A. 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.

  19. Intense combined source of neutrons and photons for interrogation based on compact deuteron RF accelerator

    DOE PAGESBeta

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

    2015-06-18

    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(?15.1), 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 (more »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, 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.« less

  20. Development of a Permanent-Magnet Microwave Ion Source for a Sealed-Tube Neutron Generator

    SciTech Connect

    Waldmann, Ole; Ludewigt, Bernhard

    2011-03-31

    A microwave ion source has been designed and constructed for use with a sealed-tube, high-yield neutron generator. When operated with a tritium-deuterium gas mixture the generator will be capable of producing 5*1011 n/s in non-proliferation applications. Microwave ion sources are well suited for such a device because they can produce high extracted beam currents with a high atomic fraction at low gas pressures of 0.2-0.3 Pa required for sealed tube operation. The magnetic field strength for achieving electron cyclotron resonance (ECR) condition, 87.5 mT at 2.45 GHz microwave frequency, was generated and shaped with permanent magnets surrounding the plasma chamber and a ferromagnetic plasma electrode. This approach resulted in a compact ion source that matches the neutron generator requirements. The needed proton-equivalent extracted beam current density of 40 mA/cm^2 was obtained at moderate microwave power levels of 400 W. Results on magnetic field design, pressure dependency and atomic fraction measured for different wall materials are presented.

  1. Intense combined source of neutrons and photons for interrogation based on compact deuteron RF accelerator

    SciTech Connect

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

    2015-06-18

    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(?15.1), 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, 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.

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

    NASA Astrophysics Data System (ADS)

    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.

  3. Recent advances in high pressure neutron scattering at the Spallation Neutron Source at Oak Ridge National Laboratory

    NASA Astrophysics Data System (ADS)

    Tulk, C.; dos Santos, A.; Klug, D.; Guthrie, M.; Machida, S.; Molaison, J.

    2012-12-01

    There have been significant improvements in the operation of the high pressure diffractometer, SNAP, at the Spallation Neutron Source over the past two years. This talk will highlight the current capacities which include low temperature systems, high temperature systems, and the introduction of new pressure cell technology that is based on supported diamond anvils and, with advances in software, is particularly suited for powder diffraction. Specific examples of our recent research will focus on high pressure transitions in hydrogen bonded systems such as methane and CO2 hydrate. The high pressure hexagonal phase of methane hydrate is studied to determine the nature of the hydrate cage loading, this provides detailed experimental data that will lead to better intermolecular potentials for methane - methane interactions, particularly when methane molecules are in close contact and strongly repelling. The high pressure structural systematics of carbon dioxide hydrate is reported. While the structural transformation sequence of most hydrates progress from sI (or sII) to the hexagonal form then to a flied ice structure, CO2 hydrate is an example of a system that skips the hexagonal phase and transforms directly into the filled ice structure. Finally examples of using SNAP to study disorder in amorphous systems will be given. Particularly amorphous vapor co-deposits of water, known as amorphous solid water, and clathrate forming molecules such as CO2, and the structural response of these systems to increased pressure at low temperature.

  4. Characterization of core debris/concrete interactions for the Advanced Neutron Source

    SciTech Connect

    Hyman, C.R.; Taleyarkhan, R.P.

    1992-02-01

    This report provides the results of a recent study conducted to explore the molten core/concrete interaction (MCCI) issue for the Advanced Neutron Source (ANS). The need for such a study arises from the potential threats to reactor system integrity posed by MCCI. These threats include direct attack of the concrete basemat of the containment; generation and release of large quantities of gas that can pressurize the containment; the combustion threat of these gases; and the potential generation, release, and transport of radioactive aerosols to the environment.

  5. Electron cloud development in the Proton Storage Ring and in theSpallation Neutron Source

    SciTech Connect

    Pivi, M.T.F.; Furman, M.A.

    2002-10-08

    We have applied our simulation code "POSINST" to evaluatethe contribution to the growth rate of the electron-cloud instability inproton storage rings. Recent simulation results for the main features ofthe electron cloud in the storage ring of the Spallation Neutron Source(SNS) at Oak Ridge, and updated results for the Proton Storage Ring (PSR)at Los Alamos are presented in this paper. A key ingredient in our modelis a detailed description of the secondary emitted-electron energyspectrum. A refined model for the secondary emission process includingthe so-called true secondary, rediffused and backscattered electrons hasrecently been included in the electron-cloud code.

  6. A Los Alamos design study for a high-power spallation-neutron-source driver

    SciTech Connect

    Jason, A.J.; Hardekopf, R.A.; Macek, R.W.; Schriber, S.O.; Thiessen, H.A.; Woods, R.

    1993-06-01

    A design study for an accelerator-driven spallation-neutron source is underway at Los Alamos. The driver, based on the LAMPF facility, produces a 1-MW proton beam and is upgradable to 5 MW. After linear acceleration to full energy, an H-beam is accumulated for approximately I ms in a compressor ring and then extracted to produce an intense proton burst, less than 1 {mu}s long, onto a spallation target system with a 60-Hz cycle rate. The design uses existing infrastructure insofar as possible while maintaining project goals. This paper summarizes the system specifications and design status.

  7. Testing Procedures and Results of the Prototype Fundamental Power Coupler for the Spallation Neutron Source

    SciTech Connect

    Stirbet, M; Campisi, I E; Daly, E F; Davis, G K; Drury, M; Kneisel, P; Myneni, G; Powers, T; Schneider, W J; Wilson, K M; Kang, Y; Cummings, K A; Hardek, T

    2001-06-01

    High-power RF testing with peak power in excess of 500 kW has been performed on prototype Fundamental Power Couplers (FPC) for the Spallation Neutron Source superconducting (SNS) cavities. The testing followed the development of procedures for cleaning, assembling and preparing the FPC for installation in the test stand. The qualification of the couplers has occurred for the time being only in a limited set of conditions (travelling wave, 20 pps) as the available RF system and control instrumentation are under improvement.

  8. A strong shallow heat source in the accreting neutron star MAXI J0556-332

    E-print Network

    Deibel, Alex; Brown, Edward F; Page, Dany

    2015-01-01

    An accretion outburst in an X-ray transient deposits material onto the neutron star primary; this accumulation of matter induces reactions in the neutron star's crust. During the accretion outburst these reactions heat the crust out of thermal equilibrium with the core. When accretion halts, the crust cools to its long-term equilibrium temperature on observable timescales. Here we examine the accreting neutron star transient MAXI J0556-332, which is the hottest transient, at the start of quiescence, observed to date. Models of the quiescent light curve require a large deposition of heat in the shallow outer crust from an unknown source. The additional heat injected is $\\approx 4\\textrm{-}10\\,\\mathrm{MeV}$ per accreted nucleon; when the observed decline in accretion rate at the end of the outburst is accounted for, the required heating increases to $\\approx 6\\textrm{-}16\\,\\mathrm{MeV}$. This shallow heating is still required to fit the lightcurve even after taking into account a second accretion episode, uncer...

  9. Design progress of cryogenic hydrogen system for China Spallation Neutron Source

    SciTech Connect

    Wang, G. P.; Zhang, Y.; Xiao, J.; He, C. C.; Ding, M. Y.; Wang, Y. Q.; Li, N.; He, K.

    2014-01-29

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

  10. Design progress of cryogenic hydrogen system for China Spallation Neutron Source

    NASA Astrophysics Data System (ADS)

    Wang, G. P.; Zhang, Y.; Xiao, J.; He, C. C.; Ding, M. Y.; Wang, Y. Q.; Li, N.; He, K.

    2014-01-01

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

  11. Neutron dose equivalents at the Advanced Light Source: Calculation using the MORSE code vs estimated values

    SciTech Connect

    Sun, Rai-Ko S.

    1991-02-01

    The Advanced Light Source (ALS) complex at the Lawrence Berkeley Laboratory (LBL) is surrounded by a mezzanine and auxiliary buildings. An important radiological problem is the neutron dose equivalent in nearby occupied areas and at the LBL site boundary. Both the direct and air-scattered (skyshine) components of the neutron dose equivalents are evaluated using the neutron transport code MORSE. The shielding was designed using an empirical method based on data scaled from a 1977 SLAC experiment and on a compilation of experimental and theoretical material relevant to shielding of electron accelerators. From the MORSE calculation, the total occupational dose equivalent rate in the center of the ALS mezzanine was found to be less than 1 mSv (100 mrem) per shift year (2000-hr), and the total environmental dose equivalent rate at the ALS boundary, 125 m from the storage-ring center, was found to be about 302 {mu}Sv (30 mrem) per year. A comparison of the dose equivalents shows that the calculated MORSE-code values agree well with those estimated by the empirical method. That is, dose equivalents obtained by the empirical methods are of the same order of magnitude as the corresponding MORSE values. 7 refs., 7 figs., 2 tabs.

  12. Operational performance characteristics of the WISH detector array on the ISIS spallation neutron source

    NASA Astrophysics Data System (ADS)

    Duxbury, D.; Khalyavin, D.; Manuel, P.; Raspino, D.; Rhodes, N.; Schooneveld, E.; Spill, E.

    2014-12-01

    The performance of the position sensitive neutron detector array of the WISH diffractometer is discussed. WISH (Wide angle In a Single Histogram) is one of the seven instruments currently available for users on the second target station (TS2) of the ISIS spallation neutron source, and is used mainly for magnetic studies of materials. WISH is instrumented with an array of 10 detector panels, covering an angular range of 320o, orientated in two semi-cylindrical annuli around a central sample position at a radius of 2.2m. In total the 10 detector panels are composed of 1520 3He based position sensitive detector tubes. Each tube has an active length of one metre, a diameter of 8mm and is filled with 3He at 15 bar. The specification for the WISH detectors included a neutron detection efficiency of 50% at a neutron wavelength of 1Å with good gamma rejection. A position resolution better than 8 mm FWHM along the length of the tubes was also required which has been met experimentally. Results obtained from the detector arrays showing pulse height and positional information both prior to and post installation are shown. The first 5 of the 10 detector panels have been operational since 2009, and comparable diffraction data from powder and single crystal samples taken from the remaining 5 panels (installation completed in 2013) shows that we have a detector array with a highly stable performance which is easily assembled and maintained. Finally some real user data is shown, highlighting the excellent quality of data attainable with this instrument.

  13. IMPROVED COMPUTATIONAL CHARACTERIZATION OF THE THERMAL NEUTRON SOURCE FOR NEUTRON CAPTURE THERAPY RESEARCH AT THE UNIVERSITY OF MISSOURI

    SciTech Connect

    Stuart R. Slattery; David W. Nigg; John D. Brockman; M. Frederick Hawthorne

    2010-05-01

    Parameter studies, design calculations and initial neutronic performance measurements have been completed for a new thermal neutron beamline to be used for neutron capture therapy cell and small-animal radiobiology studies at the University of Missouri Research Reactor. The beamline features the use of single-crystal silicon and bismuth sections for neutron filtering and for reduction of incident gamma radiation. The computational models used for the final beam design and performance evaluation are based on coupled discrete-ordinates and Monte Carlo techniques that permit detailed modeling of the neutron transmission properties of the filtering crystals with very few approximations. This is essential for detailed dosimetric studies required for the anticipated research program.

  14. Simultaneous usage of pinhole and penumbral apertures for imaging small scale neutron sources from inertial confinement fusion experiments

    SciTech Connect

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

    2012-10-15

    Inertial confinement fusion experiments at the National Ignition Facility are designed to understand the basic principles of creating self-sustaining fusion reactions by laser driven compression of deuterium-tritium (DT) filled cryogenic plastic capsules. The neutron imaging diagnostic provides information on the distribution of the central fusion reaction region and the surrounding DT fuel by observing neutron images in two different energy bands for primary (13-17 MeV) and down-scattered (6-12 MeV) neutrons. From this, the final shape and size of the compressed capsule can be estimated and the symmetry of the compression can be inferred. These experiments provide small sources with high yield neutron flux. An aperture design that includes an array of pinholes and penumbral apertures has provided the opportunity to image the same source with two different techniques. This allows for an evaluation of these different aperture designs and reconstruction algorithms.

  15. The fast neutron fluence and the activation detector activity calculations using the effective source method and the adjoint function

    SciTech Connect

    Hep, J.; Konecna, A.; Krysl, V.; Smutny, V.

    2011-07-01

    This paper describes the application of effective source in forward calculations and the adjoint method to the solution of fast neutron fluence and activation detector activities in the reactor pressure vessel (RPV) and RPV cavity of a VVER-440 reactor. Its objective is the demonstration of both methods on a practical task. The effective source method applies the Boltzmann transport operator to time integrated source data in order to obtain neutron fluence and detector activities. By weighting the source data by time dependent decay of the detector activity, the result of the calculation is the detector activity. Alternatively, if the weighting is uniform with respect to time, the result is the fluence. The approach works because of the inherent linearity of radiation transport in non-multiplying time-invariant media. Integrated in this way, the source data are referred to as the effective source. The effective source in the forward calculations method thereby enables the analyst to replace numerous intensive transport calculations with a single transport calculation in which the time dependence and magnitude of the source are correctly represented. In this work, the effective source method has been expanded slightly in the following way: neutron source data were performed with few group method calculation using the active core calculation code MOBY-DICK. The follow-up neutron transport calculation was performed using the neutron transport code TORT to perform multigroup calculations. For comparison, an alternative method of calculation has been used based upon adjoint functions of the Boltzmann transport equation. Calculation of the three-dimensional (3-D) adjoint function for each required computational outcome has been obtained using the deterministic code TORT and the cross section library BGL440. Adjoint functions appropriate to the required fast neutron flux density and neutron reaction rates have been calculated for several significant points within the RPV and RPV cavity of the VVER-440 reacto rand located axially at the position of maximum power and at the position of the weld. Both of these methods (the effective source and the adjoint function) are briefly described in the present paper. The paper also describes their application to the solution of fast neutron fluence and detectors activities for the VVER-440 reactor. (authors)

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

    NASA Astrophysics Data System (ADS)

    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 ?m size are resolved when projected at high magnification.

  17. Is the Bursting Radio-source GCRT J1745-3009 a Double Neutron Star Binary ?

    E-print Network

    R. Turolla; A. Possenti; A. Treves

    2005-06-18

    GCRT J1745-3009 is a peculiar transient radio-source in the direction of the Galactic Center. It was observed to emit a series of ~ 1 Jy bursts at 0.33 GHz, with typical duration ~ 10 min and at apparently regular intervals of ~ 77 min. If the source is indeed at the distance of the Galactic Center as it seems likely, we show that its observational properties are compatible with those expected from a double neutron star binary, similar to the double pulsar system J0737-3039. In the picture we propose the (coherent) radio emission comes from the shock originating in the interaction of the wind of the more energetic pulsar with the magnetosphere of the companion. The observed modulation of the radio signal is the consequence of an eccentric orbit, along which the separation between the two stars varies. This cyclically drives the shock inside the light cylinder radius of the less energetic pulsar.

  18. COHERENT First Steps for an Experimental Neutrino Program at the Spallation Neutron Source

    NASA Astrophysics Data System (ADS)

    Hornback, Donald; Coherent Collaboration

    2015-04-01

    The COHERENT Collaboration has been formed to make a first measurement of coherent neutral-current elastic neutrino-nucleus scattering (CENNS). Toward this, the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory has been identified as the premier facility for this measurement due to several factors, including: high neutrino flux, appropriate neutrino energies, SNS beam time structure for significant background reduction, and the ability to suitably place detector systems sufficiently near the neutrino source. An ongoing background measurement campaign at the SNS is identifying candidate locations and characterizing primary background signals for a CENNS detector system. The result of current efforts and their implications for a CENNS measurement at the SNS will be discussed.

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

    SciTech Connect

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

    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.

  20. Calculation of the ultracold neutron yield from a superfluid helium source in the WWR-M reactor

    NASA Astrophysics Data System (ADS)

    Serebrov, A. P.; Fomin, A. K.

    2015-08-01

    A new high-intensity source of ultracold neutrons (UCNs) is being developed on the WWR-M reactor at the Petersburg Nuclear Physics Institute. In this source, superfluid helium will be used, which will make it possible to attain the UCN density 2 to 3 orders of magnitude higher than in available sources in the world. With the most intense UCN source, the WWR-M reactor will become an international center of fundamental studies with UCNs. As a result of optimization of parameters of this source, the UCN density in the main trap is estimated as ?35 L = 1.3 × 104 neutrons/cm3 (for a trap with a volume of 35 L) and ?350 L = 8.4 × 103 neutrons/cm3 (for a trap with a volume of 350 L). For an auxiliary trap located on the platform, the calculated UCN densities are ?35 L = 150 neutrons/cm3 and ?350 L = 120 neutrons/cm3. The ratio of UCN densities amounts to 2 orders of magnitude and indicates the effectiveness of the method of UCN extraction in the case of accumulation in superfluid helium.

  1. Calculation of Ambient (H*(10)) and Personal (Hp(10)) Dose Equivalent from a 252Cf Neutron Source

    SciTech Connect

    Traub, Richard J.

    2010-03-26

    The purpose of this calculation is to calculate the neutron dose factors for the Sr-Cf-3000 neutron source that is located in the 318 low scatter room (LSR). The dose factors were based on the dose conversion factors published in ICRP-21 Appendix 6, and the Ambient dose equivalent (H*(10)) and Personal dose equivalent (Hp(10)) dose factors published in ICRP Publication 74.

  2. Neutronics methods, models, and applications at the Idaho National Engineering Laboratory for the advanced neutron source reactor three-element core design

    SciTech Connect

    Wemple, C.A.; Schnitzler, B.G.; Ryskamp, J.M.

    1995-08-01

    A summary of the methods and models used to perform neutronics analyses on the Advanced Neutron Source reactor three-element core design is presented. The applications of the neutral particle Monte Carlo code MCNP are detailed, as well as the expansion of the static role of MCNP to analysis of fuel cycle depletion calculations. Results to date of these applications are presented also. A summary of the calculations not yet performed is also given to provide a {open_quotes}to-do{close_quotes} list if the project is resurrected.

  3. A portable neutron/tunable x-ray source based on inertial electrostatic confinement

    NASA Astrophysics Data System (ADS)

    Miley, George H.

    2001-07-01

    Inertial Electrostatic Confinement (IEC) offers a unique ion-beam-plasma-target configuration for production of neutrons via D-D or D-T fusion reactions. Research at the U. of IL has developed a unique "STAR" mode of operation where a basketball-shaped grid in the spherical (r˜15 cm) vacuum vessel creates intense ion beams focused at the center of the vessel, forming a dense fusing plasma core (target). Key advantages of this unique design are that grid sputtering is greatly reduced and good beam focusing is achieved. Commercial versions of this concept have been developed that offer 107 2.45-MeV D-D neutrons/sec (or 109/sec D-T). Such units are typically used to replace Cf-252 sources for industrial NAA. Next generation devices with rates above 109/sec D-D are currently under development. The IEC also provides a small tunable x-ray source (5-100 keV) for research applications by reversing the grid potential and also installing electron emitters. The changeover requires several hours down time, or, if needed, a separate dedicated IEC x-ray unit could be constructed.

  4. Determination of the optimum-size californium-252 neutron source for borehole capture gamma-ray analysis

    USGS Publications Warehouse

    Senftle, F.E.; Macy, R.J.; Mikesell, J.L.

    1979-01-01

    The fast- and thermal-neutron fluence rates from a 3.7 ??g 252Cf neutron source in a simulated borehole have been measured as a function of the source-to-detector distance using air, water, coal, iron ore-concrete mix, and dry sand as borehole media. Gamma-ray intensity measurements were made for specific spectral lines at low and high energies for the same range of source-to-detector distances in the iron ore-concrete mix and in coal. Integral gamma-ray counts across the entire spectrum were also made at each source-to-detector distance. From these data, the specific neutron-damage rate, and the critical count-rate criteria, we show that in an iron ore-concrete mix (low hydrogen concentration), 252Cf neutron sources of 2-40 ??g are suitable. The source size required for optimum gamma-ray sensitivity depends on the energy of the gamma ray being measured. In a hydrogeneous medium such as coal, similar measurements were made. The results show that sources from 2 to 20 ??g are suitable to obtain the highest gamma-ray sensitivity, again depending on the energy of the gamma ray being measured. In a hydrogeneous medium, significant improvement in sensitivity can be achieved by using faster electronics; in iron ore, it cannot. ?? 1979 North-Holland Publishing Co.

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

    SciTech Connect

    Powell, J.; Ludewig, H.; Todosow, M.; Reich, M.

    1995-06-01

    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 ({approximately} 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.

  6. Plans for an Integrated Front-End Test Stand at the Spallation Neutron Source

    SciTech Connect

    Champion, Mark S; Aleksandrov, Alexander V; Crofford, Mark T; Heidenreich, Dale A; Kang, Yoon W; Moss, John; Roseberry, Jr., R Tom; Schubert, James Phillip

    2012-01-01

    A spare Radio-Frequency Quadrupole (RFQ) is presently being fabricated by industry with delivery to Oak Ridge National Laboratory planned in late 2012. The establishment of a test stand at the Spallation Neutron Source site is underway so that complete acceptance testing can be performed during the winter of 2012-2013. This activity is the first step in the establishment of an integrated front-end test stand that will include an ion source, low-energy beam transport (LEBT), RFQ, medium-energy beam transport, diagnostics, and a beam dump. The test stand will be capable of delivering an H- ion beam of up to 50 mA with a pulse length of 1 ms and a repetition rate of 60 Hz or a proton beam of up to 50 mA, 100us, 1Hz. The test stand will enable the following activities: complete ion source characterization; development of a magnetic LEBT chopper; development of a two-source layout; development of beam diagnostics; and study of beam dynamics of high intensity beam.

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

    SciTech Connect

    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.

  8. LOW LOSS DESIGN OF THE LINAC AND ACCUMULATOR RING FOR THE SPALLATION NEUTRON SOURCE.

    SciTech Connect

    RAPARIA,D.

    2003-02-03

    The Spallation Neutron Source (SNS) is a second generation pulsed neutron source and is presently in the fourth year of a seven-year construction cycle at Oak Ridge National Laboratory. A collaboration of six national laboratories (ANL, BNL, LANL, LBNL, ORNL, TJNAF) is responsible for the design and construction of the various subsystems. The operation of the facility will begin in 2006 and deliver a 1.0 GeV, 1.4 MW proton beam with pulse length of 650 nanosecond at a repetition rate of 60 Hz, on a liquid mercury target. It consists of an RF volume H{sup -} source of 50 mA peak current at 6% duty; an all electrostatic Low-Energy Beam Transport (LEBT) which also serves as a first stage beam chopper with {+-} 25 ns rise/fall time; a 402.5 MHz, 4-vane Radio-Frequency Quadrupole (RFQ) for acceleration up to 2.5 MeV; a Medium Energy Beam Transport (MEBT) housing a second stage chopper (<{+-} 10ns rise/fall), an adjustable beam halo scraper, and diagnostics devices; a 6-tank Drift Tube Linac (DTL) with permanent magnet quadrupoles up to 87 MeV; an 805 MHz, 4-module, Side Coupled Cavity Linac (CCL) up to 186 MeV; an 805 MHz, superconducting RF (SRF) linac with eleven medium beta ({beta} = 0.61) cryo-modules and twelve high beta ({beta} = 0.81) cryo-modules accelerating the beam to the full energy; a High Energy Beam transport (HEBT) for diagnostics, transverse and longitudinal collimation, energy correction, painting and matching; an accumulator ring compressing the 1 GeV, 1 ms pulse to 650 ns for delivery onto the target through a Ring to Target Beam Transport (RTBT) with transverse collimators.

  9. Neutron range spectrometer

    DOEpatents

    Manglos, S.H.

    1988-03-10

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

  10. Advanced neutron source project information management. A model for the future

    SciTech Connect

    King-Jones, K.; Cleaves, J.

    1995-12-31

    The Advanced Neutron Source (ANS) is a proposed new research facility that will provide steady-state beams of neutrons for experiments by more than 1000 researchers per year in the fields of materials science and engineering, biology, chemistry, materials analysis, and nuclear science. The facility will also include irradiation capabilities to produce radioisotopes for medical applications, research, industry, and materials testing. This paper discusses the architecture and data flow used by the project, some quantitative examinations of potential cost savings and return on investment and software applications used to generate and manage data across IBM-compatible personal computers, Macintosh, and Unix-based workstations. Personnel management aspects addressed include providing paper copy to users only when needed for adequate technical review, using graded approaches to providing support for numerous user-needed software applications, and implementing a phased approach to compliance with computer-aided acquisition and logistic support (CALS) standards that allows sufficient user flexibility for performing technical tasks while providing needed data sharing and integration.

  11. Advanced Neutron Source project information management: A model for the future

    SciTech Connect

    King-Jones, K.; Cleaves, J.

    1995-12-31

    The Advanced Neutron Source (ANS) is a proposed new research facility that will provide steady-state beams of neutrons for experiments by more than 1,000 researchers per year in the fields of materials science and engineering, biology, chemistry, materials analysis, and nuclear science. The facility will also include irradiation capabilities to produce radioisotopes for medical applications, research, industry, and materials testing. This paper discusses the architecture and data flow used by the project, some quantitative examinations of potential cost savings and return on investment, and software applications used to generate and manage data across IBM-compatible personal computers, Macintosh, and Unix-based workstations. Personnel management aspects addressed include providing paper copy to users only when needed for adequate technical review, using graded approaches to providing support for numerous user-needed software applications, and implementing a phased approach to compliance with computer-aided acquisition and logistic support (CALS) standards that allows sufficient user flexibility for performing technical tasks while providing needed data sharing and integration.

  12. The Status of Research Regarding Magnetic Mirrors as a Fusion Neutron Source or Power Plant

    SciTech Connect

    Simonen, T

    2008-12-23

    Experimental results, theory and innovative ideas now point with increased confidence to the possibility of a Gas Dynamic Trap (GDT) neutron source which would be on the path to an attractively simple Axisymmetric Tandem Mirror (ATM) power plant. Although magnetic mirror research was terminated in the US 20 years ago, experiments continued in Japan (Gamma 10) and Russia (GDT), with a very small US effort. This research has now yielded data, increased understanding, and generated ideas resulting in the new concepts described here. Early mirror research was carried out with circular axisymmetric magnets. These plasmas were MHD unstable due to the unfavorable magnetic curvature near the mid-plane. Then the minimum-B concept emerged in which the field line curvature was everywhere favorable and the plasma was situated in a MHD stable magnetic well (70% average beta in 2XII-B). The Ioffe-bar or baseball-coil became the standard for over 40 years. In the 1980's, driven by success with minimum-B stabilization and the control of ion cyclotron instabilities in PR6 and 2XII-B, mirrors were viewed as a potentially attractive concept with near-term advantages as a lower Q neutron source for applications such as a hybrid fission fuel factory or toxic waste burner. However there are down sides to the minimum-B geometry: coil construction is complex; restraining magnetic forces limit field strength and mirror ratios. Furthermore, the magnetic field lines have geodesic curvature which introduces resonant and neoclassical radial transport as observed in early tandem mirror experiments. So what now leads us to think that simple axisymmetric mirror plasmas can be stable? The Russian GDT experiment achieves on-axis 60% beta by peaking of the kinetic plasma pressure near the mirror throat (where the curvature is favorable) to counter-balance the average unfavorable mid-plane curvature. Then a modest augmentation of plasma pressure in the expander results in stability. The GDT experiments have confirmed the physics of effluent plasma stabilization predicted by theory. The plasma had a mean ion energy of 10 keV and a density of 5e19m-3. If successful, the axisymmetric tandem mirror extension of the GDT idea could lead to a Q {approx} 10 power plant of modest size and would yield important applications at lower Q. In addition to the GDT method, there are four other ways to augment stability that have been demonstrated; including: plasma rotation (MCX), diverter coils (Tara), pondermotive (Phaedrus & Tara), and end wall funnel shape (Nizhni Novgorod). There are also 5 stabilization techniques predicted, but not yet demonstrated: expander kinetic pressure (KSTM-Post), Pulsed ECH Dynamic Stabilization (Post), wall stabilization (Berk), non-paraxial end mirrors (Ryutov), and cusp ends (Kesner). While these options should be examined further together with conceptual engineering designs. Physics issues that need further analysis include: electron confinement, MHD and trapped particle modes, analysis of micro stability, radial transport, evaluation and optimization of Q, and the plasma density needed to bridge to the expansion-region. While promising all should be examined through increased theory effort, university-scale experiments, and through increased international collaboration with the substantial facilities in Russia and Japan The conventional wisdom of magnetic mirrors was that they would never work as a fusion concept for a number of reasons. This conventional wisdom is most probably all wrong or not applicable, especially for applications such as low Q (DT Neutron Source) aimed at materials testing or for a Q {approx} 3-5 fusion neutron source applied to destroying actinides in fission waste and breeding of fissile fuel.

  13. Spallation Neutron Source Availability Top-Down Apportionment Using Characteristic Factors and Expert Opinion

    SciTech Connect

    Haire, M.J.; Schryver, J.C.

    1999-10-01

    Apportionment is the assignment of top-level requirements to lower tier elements of the overall facility. A method for apportioning overall facility availability requirements among systems and subsystems is presented. Characteristics that influence equipment reliability and maintainability are discussed. Experts, using engineering judgment, scored each characteristic for each system whose availability design goal is to be established. The Analytic Hierarchy Process (AHP) method is used to produce a set of weighted rankings for each characteristic for each alternative system. A mathematical model is derived which incorporates these weighting factors. The method imposes higher availability requirements on those systems in which an incremental increase in availability is easier to achieve, and lower availability requirements where greater availability is more difficult and costly. An example is given of applying this top-down apportionment methodology to the Spallation Neutron Source (SNS) facility.

  14. Low-level rf control of Spallation Neutron Source: System and characterization

    NASA Astrophysics Data System (ADS)

    Ma, Hengjie; Champion, Mark; Crofford, Mark; Kasemir, Kay-Uwe; Piller, Maurice; Doolittle, Lawrence; Ratti, Alex

    2006-03-01

    The low-level rf control system currently commissioned throughout the Spallation Neutron Source (SNS) LINAC evolved from three design iterations over 1 yr intensive research and development. Its digital hardware implementation is efficient, and has succeeded in achieving a minimum latency of less than 150 ns which is the key for accomplishing an all-digital feedback control for the full bandwidth. The control bandwidth is analyzed in frequency domain and characterized by testing its transient response. The hardware implementation also includes the provision of a time-shared input channel for a superior phase differential measurement between the cavity field and the reference. A companion cosimulation system for the digital hardware was developed to ensure a reliable long-term supportability. A large effort has also been made in the operation software development for the practical issues such as the process automations, cavity filling, beam loading compensation, and the cavity mechanical resonance suppression.

  15. The Development of Automatic Sequences for the RF and Cryogenic Systems at the Spallation Neutron Source

    SciTech Connect

    Gurd, Pamela; Casagrande, Fabio; Mccarthy, Michael; Strong, William; Ganni, Venkatarao

    2005-10-01

    Automatic sequences both ease the task of operating a complex machine and ensure procedural consistency. At the Spallation Neutron Source project (SNS), a set of automatic sequences have been developed to perform the start up and shut down of the high power RF systems. Similarly, sequences have been developed to perform backfill, pump down, automatic valve control and energy management in the cryogenic system. The sequences run on Linux soft input-output controllers (IOCs), which are similar to ordinary EPICS (Experimental Physics and Industrial Control System) IOCs in terms of data sharing with other EPICS processes, but which share a Linux processor with other such processors. Each sequence waits for a command from an operator console and starts the corresponding set of instructions, allowing operators to follow the sequences either from an overview screen or from detail screens. We describe each system and our operational experience with it.

  16. Radiological Aspects of Heavy Metal Liquid Targets for Accelerator-Driven Systems as Intense Neutron Sources

    NASA Astrophysics Data System (ADS)

    Gai, E. V.; Ignatyuk, A. V.; Lunev, V. P.; Shubin, Yu. N.

    2001-11-01

    General problems arising in development of intense neutron sources as a part of accelerator-driven systems and first experience accumulated in IPPE during last several years are briefly discussed. The calculation and analysis of nuclear-physical properties of the targets, such as the accumulation of spallation reaction products, activity and heat release for various versions of heavy liquid metal targets were performed in IPPE. The sensitivity of the results of calculations to the various sets of nuclear data was considered. The main radiology characteristics of the lead-bismuth target, which is now under construction in the frame of ISTC Project # 559, are briefly described. The production of short-lived nuclides was estimated, the total activity and volatile nuclide accumulation, residual heat release, the energies of various decay modes were analysed.

  17. Globus-M plasma physics research for fusion application and compact neutron source development

    NASA Astrophysics Data System (ADS)

    Gusev, V. K.; Bakharev, N. N.; Ber, B. Ya; Bulanin, V. V.; Chernyshev, F. V.; Dyachenko, V. V.; Goncharov, P. R.; Gusakov, E. Z.; Iblyaminova, A. D.; Irzak, M. A.; Kaveeva, E. G.; Khitrov, S. A.; Khromov, N. A.; Kornev, V. A.; Kurskiev, G. S.; Melnik, A. D.; Minaev, V. B.; Mineev, A. B.; Mironov, M. I.; Novokhatsky, A. N.; Patrov, M. I.; Petrov, A. V.; Petrov, Yu V.; Rozhansky, V. A.; Sakharov, N. V.; Saveliev, A. N.; Senichenkov, I. Yu; Shchegolev, P. B.; Shcherbinin, O. N.; Tolstyakov, S. Yu; Varfolomeev, V. I.; Voronin, A. V.; Yashin, A. Yu

    2016-01-01

    During the past decade, plasma physics research promoting the physics base of ITER and developing novel concepts such as a compact fusion neutron source has been conducted on the Globus-M spherical tokamak (ST) (R??=??36?cm, a??=??24?cm, I p?????250 kA, B T?????0.4 T). Tokamak reconstruction is imminent. The upgraded tokamak Globus-M2 will have the same vacuum chamber and an enhanced magnetic system to provide B T??=??1 T and I p??=??500 kA. In this paper we outline the most important research directions and the main results obtained on Globus-M and make some predictions about the possibilities and parameters of Globus-M2.

  18. Numerical studies of the flux-to-current ratio method in the KIPT neutron source facility

    SciTech Connect

    Cao, Y.; Gohar, Y.; Zhong, Z.

    2013-07-01

    The reactivity of a subcritical assembly has to be monitored continuously in order to assure its safe operation. In this paper, the flux-to-current ratio method has been studied as an approach to provide the on-line reactivity measurement of the subcritical system. Monte Carlo numerical simulations have been performed using the KIPT neutron source facility model. It is found that the reactivity obtained from the flux-to-current ratio method is sensitive to the detector position in the subcritical assembly. However, if multiple detectors are located about 12 cm above the graphite reflector and 54 cm radially, the technique is shown to be very accurate in determining the k{sub eff} this facility in the range of 0.75 to 0.975. (authors)

  19. EXPERIENCE WITH COLLABORATIVE DEVELOPMENT FOR THE SPALLATION NEUTRON SOURCE FROM A PARTNER LAB PERSPECTIVE.

    SciTech Connect

    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.

  20. Basics of Fusion-Fissison Research Facility (FFRF) as a Fusion Neutron Source

    SciTech Connect

    Leonid E. Zakharov

    2011-06-03

    FFRF, standing for the Fusion-Fission Research Facility represents an option for the next step project of ASIPP (Hefei, China) aiming to a first fusion-fission multifunctional device [1]. FFRF strongly relies on new, Lithium Wall Fusion plasma regimes, the development of which has already started in the US and China. With R/a=4/1m/m, Ipl=5 MA, Btor=4-6 T, PDT=50- 100 MW, Pfission=80-4000MW, 1 m thick blanket, FFRF has a unique fusion mission of a stationary fusion neutron source. Its pioneering mission of merging fusion and fission consists in accumulation of design, experimental, and operational data for future hybrid applications.

  1. Application of the modified neutron source multiplication method to the prototype FBR Monju

    SciTech Connect

    Truchet, G.; Van Rooijen, W. F. G.; Shimazu, Y.

    2012-07-01

    The Modified Neutron Source Method (MNSM) is applied to the Monju reactor. This static method to estimate sub-criticality has already given good results on commercial Pressurized Water Reactors. The MNSM consists both in the extraction of the fundamental mode seen by a detector to avoid the effect of higher modes near sources, and the correction of flux distortion effects due to control rod movement. Among Monju's particularities that have a big influence on MNSM factors are: the presence of two californium sources and the position of the detector, which is located far from the core outside of the reactor vessel. The importance of spontaneous fission and ({alpha},n) reactions, which have increased during the shutdown period of 15 years, will also be discussed. In order to evaluate the detector count rate, an analytical propagation has been conducted from the reactor vessel. For two subcritical states, an estimation of the reactivity has been made and compared to experimental data obtained in the restart experiments at Monju (2010). Results indicate a good agreement between the MNSM reactivity and the reactivity measured with other methods. The reactivity dependence of the correction to apply to point kinetic equation is discussed. (authors)

  2. A DOUBLE NEUTRON STAR MERGER ORIGIN FOR THE COSMOLOGICAL RELATIVISTIC FADING SOURCE PTF11agg?

    SciTech Connect

    Wu, Xue-Feng; Gao, He; Ding, Xuan; Zhang, Bing; Dai, Zi-Gao; Wei, Jian-Yan

    2014-01-20

    The Palomar Transient Factory (PTF) team recently reported the discovery of a rapidly fading optical transient source, PTF11agg. A long-lived scintillating radio counterpart was identified, but the search for a high-energy counterpart showed negative results. The PTF team speculated that PTF11agg may represent a new class of relativistic outbursts. Here we suggest that a neutron star (NS)-NS merger system with a supra-massive magnetar central engine could be a possible source to power such a transient, if our line of sight is not on the jet axis direction of the system. These systems are also top candidates for gravitational wave sources to be detected in the advanced LIGO/Virgo era. We find that the PTF11agg data could be explained well with such a model, suggesting that at least some gravitational wave bursts due to NS-NS mergers may be associated with such a bright electromagnetic counterpart without a ?-ray trigger.

  3. Reconstruction algorithm for point source neutron imaging through finite thickness scintillator

    NASA Astrophysics Data System (ADS)

    Wang, H.; Tang, V.; McCarrick, J.; Moran, S.

    2012-11-01

    A new inversion algorithm based on the maximum entropy method (MEM) is proposed to remove unwanted effects in fast neutron imaging which result from an uncollimated source interacting with a finitely thick scintillator. The algorithm takes as an input the image from the thick scintillator (TS) and the radiography setup geometry. The algorithm then outputs a restored image which appears as if taken with an infinitesimally thin scintillator (ITS). The inversion is accomplished by numerically generating a probabilistic model relating the ITS image to the TS image and then inverting this model on the TS image through MEM. Algorithm details as well as numerical results using MCNP simulated images are presented. This reconstruction technique can reduce the exposure time or the required source intensity without undesirable object blurring on the image by allowing the use of both thicker scintillators with higher efficiencies and closer source-to-detector distances to maximize incident radiation flux. The technique should also be applicable to high energy gamma or x-ray radiography using thick scintillators.

  4. Analysis of radiation environmental safety for China's Spallation Neutron Source (CSNS)

    NASA Astrophysics Data System (ADS)

    Wang, Qing-Bin; Wu, Qing-Biao; Ma, Zhong-Jian; Zhang, Qing-Jiang; Li, Nan; Wu, Jing-Min; Liu, Jian; Zhang, Gang

    2010-07-01

    The China Spallation Neutron Source (CSNS) is going to be located in Dalang Town, Dongguan City in the Guangdong Province. In this paper we report the results of the parameters related with environment safety based on experiential calculations and Monte Carlo simulations. The main project of the accelerator is an under ground construction. On top there is a 0.5 m concrete and 5.0 m soil covering for shielding, which can reduce the dose out of the tunnel's top down to 0.2 ?Sv/h. For the residents on the boundary of the CSNS, the dose produced by skyshine, which is caused by the penetrated radiation leaking from the top of the accelerator, is no more than 0.68 ?Sv/a. When CSNS is operating normally, the maximal annual effective dose due to the emission of gas from the tunnel is 2.40×10-3 mSv/a to the public adult, and 2.29×10-3 mSv/a to a child, both values are two orders of magnitude less than the limiting value for control and management. CSNS may give rise to an activation of the soil and groundwater in the nearest tunnels, where the main productions are 3H, 7Be, 22Na, 54Mn, etc. But the specific activity is less than the exempt specific activity in the national standard GB13376-92. So it is safe to say that the environmental impact caused by the activation of soil and groundwater is insignificant. To sum up, for CSNS, as a powerful neutron source device, driven by a high-energy high-current proton accelerator, a lot of potential factors affecting the environment exist. However, as long as effective shieldings for protection are adopted and strict rules are drafted, the environmental impact can be kept under control within the limits of the national standard.

  5. Department of Energy review of the National Spallation Neutron Source Project

    SciTech Connect

    1997-06-01

    A Department of Energy (DOE) review of the Conceptual Design Report (CDR) for the National Spallation Neutron Source (NSNS) was conducted. The NSNS will be a new high-power spallation neutron source; initially, it will operate at 1 megawatt (MW), but is designed to be upgradeable to significantly higher power, at lower cost, when accelerator and target technologies are developed for higher power. The 53-member Review Committee examined the projected cost, schedule, technical scope, and management structure described in the CDR. For each of the major components of the NSNS, the Committee determined that the project team had produced credible designs that can be expected to work well. What remains to be done is to integrate the design of these components. With the exception of the liquid mercury target, the NSNS Project will rely heavily on proven technologies and, thus, will face a relatively low risk to successful project completion. The Total Project Cost (TPC) presented to the Committee in the CDR was $1.266 billion in as-spent dollars. In general, the Committee felt that the laboratory consortium had presented a credible estimate for each of the major components but that value engineering might produce some savings. The construction schedule presented to the Committee covered six years beginning in FY 1999. The Committee questioned whether all parts of the project could be completed according to this schedule. In particular, the linac and the conventional facilities appeared to have overly optimistic schedules. The NSNS project team was encouraged to reexamine these activities and to consider a more conservative seven-year schedule. Another concern of the Committee was the management structure. In summary, the Committee felt that this Conceptual Design Report was a very credible proposal, and that there is a high probability for successful completion of this major project within the proposed budget, although the six-year proposed schedule may be optimistic.

  6. Thermal-hydraulic analysis of the liquid mercury target for the national spallation neutron source

    SciTech Connect

    Siman-Tov, M.; Wendel, M.W.; Haines, J.R.; Rogers, M.

    1997-04-01

    The National Spallation Neutron Source (NSNS) is a high-energy, accelerator-based spallation neutron source being designed by a multi-laboratory team led by Oak Ridge National Laboratory (ORNL) to achieve very high fluxes of neutrons for scientific experiments. The NSNS is proposed to have a 1 MW beam of high-energy ({approximately}1 GeV) protons upgradable to 5 MW and operating at 60 Hz with a pulse duration of 0.5 {mu}s. Peak steady-state power density in the target is about 640 MW/m{sup 3} for 1 MW, whereas the pulse instantaneous peak power density is as high as 22,000 GW/m{sup 3}. The local peak temperature rise for a single pulse over it`s time-averaged value is only 6{degrees}C, but the rate of this temperature rise during the pulse is extremely fast ({approximately}12 million {degrees}C/s). In addition to the resulting thermal shock and materials compatibility concerns, key feasibility issues for the target are related to its thermal-hydraulic performance. These include proper flow distribution, flow reversals and stagnation zones, possible {open_quotes}hot spots{close_quotes}, cooling of the beam {open_quotes}window{close_quotes}, and the challenge of mitigating the effects of thermal shock through possible injection of helium bubbles. An analytic approach was used on the PC spreadsheet EXCEL to evaluate target design options and to determine the global T/H parameters in the current concept. The general computational fluid dynamics (CFD) code CFX was used to simulate the detailed time-averaged two-dimensional thermal and flow distributions in the liquid mercury. In this paper, an overview of the project and the results of this preliminary work are presented. Heat transfer characteristics of liquid mercury under wetting and non-wetting conditions are discussed, and future directions of the program in T/H analysis and R&D are outlined.

  7. Measured Total Cross Sections of Slow Neutrons Scattered by Solid Deuterium and Implications for Ultracold Neutron Sources

    SciTech Connect

    Atchison, F.; Blau, B.; Brandt, B. van den; Brys, T.; Daum, M.; Fierlinger, P.; Hautle, P.; Henneck, R.; Heule, S.; Kirch, K.; Kohlbrecher, J.; Kuehne, G.; Konter, J.A.; Pichlmaier, A.; Wokaun, A.; Bodek, K.; Kasprzak, M.; Kuzniak, M.; Geltenbort, P.; Zmeskal, J.

    2005-10-28

    The total scattering cross sections for slow neutrons with energies in the range 100 neV to 3 meV for solid ortho-{sup 2}H{sub 2} at 18 and 5 K, frozen from the liquid, have been measured. The 18 K cross sections are found to be in excellent agreement with theoretical expectations and for ultracold neutrons dominated by thermal up scattering. At 5 K the total scattering cross sections are found to be dominated by the crystal defects originating in temperature induced stress but not deteriorated by temperature cycles between 5 and 10 K.

  8. Measured total cross sections of slow neutrons scattered by solid deuterium and implications for ultracold neutron sources.

    PubMed

    Atchison, F; Blau, B; van den Brandt, B; Bry?, T; Daum, M; Fierlinger, P; Hautle, P; Henneck, R; Heule, S; Kirch, K; Kohlbrecher, J; Kühne, G; Konter, J A; Pichlmaier, A; Wokaun, A; Bodek, K; Kasprzak, M; Ku?niak, M; Geltenbort, P; Zmeskal, J

    2005-10-28

    The total scattering cross sections for slow neutrons with energies in the range 100 neV to 3 meV for solid ortho-2H2 at 18 and 5 K, frozen from the liquid, have been measured. The 18 K cross sections are found to be in excellent agreement with theoretical expectations and for ultracold neutrons dominated by thermal up scattering. At 5 K the total scattering cross sections are found to be dominated by the crystal defects originating in temperature induced stress but not deteriorated by temperature cycles between 5 and 10 K. PMID:16383898

  9. Researchers have been using STFC's ISIS neutron and muon source to investigate cracking in train wheels and potential methods of

    E-print Network

    Researchers have been using STFC's ISIS neutron and muon source to investigate cracking in train with a great business idea. For more information about how your business could benefit from access to ISIS: Tel: +44 (0)1925 603708 Email: innovations@stfc.ac.uk Twitter: @STFC_B2B Using ISIS to optimise train wheel

  10. Gamma-ray bursts during neutron star formation. Gamma-ray bursts and transient X-ray sources

    NASA Technical Reports Server (NTRS)

    Cohen, J. M.; Desai, U. D.; Holt, S. S.

    1973-01-01

    Discussions are presented of the associations between cosmic gamma ray bursts and transient X-ray sources, and the release of gravitational binding energy during the formation of neutron stars. The model for studying the associations is described along with the release of neutrinos during the collapse of white dwarfs.

  11. Suzaku View of the Neutron Star in the Dipping Source 4U 1822-37

    NASA Technical Reports Server (NTRS)

    Sasano, Makoto; Makishima, Kazuo; Sakurai, Soki; Zhang, Zhongli; Enoto, Teruaki

    2013-01-01

    The dipping X-ray source 4U 1822-37 was observed by Suzaku on 2006 Octrober 20 for a net exposure of 37 ks. The source was detected with the XIS at a 1-10 keV flux of 5.5 ×10(exp -10) erg per square centimeter per second, and with the HXD (HXD-PIN) at a 10-50 keV flux of 8.9 ×10(exp -10) erg per square centimeter per second. With HXD-PIN, the pulsation was detected at a barycentric period of 0.592437 seconds, and its change rate was reconfirmed as -2.43 × 10(exp -12) seconds per second. The 1-50 keV spectra of 4U 1822-37 were found to be very similar to those of Her X- 1 in the slopes, cutoff and iron lines. Three iron lines (Fe Kalpha, Fe XXV, and Fe XXVI) were detected, on top of a 1-50 keV continuum that is described by an NPEX model plus a soft blackbody. In addition, a cyclotron resonance scattering feature was detected significantly ( greater than 99% confidence), at an energy of 33+/-2 keV with a depth of 0.4(sup +0.6)/(sub -0.3). Therefore, the neutron star in this source is concluded to have a strong magnetic field of 2.8 × 10(exp 12) G. Further assuming that the source has a relatively high intrinsic luminosity of several times 10(exp 37) erg per second, its spectral and timing properties are consistently explained.

  12. Design and operation of the wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source

    SciTech Connect

    Abernathy, Douglas L; Stone, Matthew B; Loguillo, Mark; Lucas, Matthew; Delaire, Olivier A; Tang, Xiaoli; Lin, J. Y. Y.; Fultz, B.

    2012-01-01

    The wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source (SNS) is optimized to provide a high neutron flux at the sample position with a large solid angle of detector coverage. The instrument incorporates modern neutron instrumentation, such as an elliptically-focused neutron guide, high speed magnetic bearing choppers and a massive array of 3He linear position sensitive detectors. Novel features of the spectrometer include the use of a large gate valve between the sample and detector vacuum chambers and the placement of the detectors within the vacuum, both of which provide a window-free final flight path to minimize background scattering while allowing rapid changing of the sample and sample environment equipment. ARCS views the SNS decoupled ambient temperature water moderator, using neutrons with incident energy typically in the range from 15 to 1500 meV. This range, coupled with the large detector coverage, allows a wide variety of studies of excitations in condensed matter, such as lattice dynamics and magnetism, in both powder and single-crystal samples. Comparisons of early results to both analytical and Monte Carlo simulation of the instrument performance demonstrate that the instrument is operating as expected and its neutronic performance is understood. ARCS is currently in the SNS user program, and continues to improve its scientific productivity by incorporating new instrumentation to increase the range of science covered and improve its effectiveness in data collection.

  13. Pneumatic sample-transfer system for use with the Lawrence Livermore National Laboratory rotating target neutron source (RTNS-I)

    SciTech Connect

    Williams, R.E.

    1981-07-01

    A pneumatic sample-transfer system is needed to be able to rapidly retrieve samples irradiated with 14-MeV neutrons at the Rotating Target Neutron Source (RTNS-I). The rabbit system, already in place for many years, has been refurbished with modern system components controlled by an LSI-11 minicomputer. Samples can now be counted three seconds after an irradiation. There are many uses for this expanded 14-MeV neutron activation capability. Several fission products difficult to isolate from mixed fission fragments can be produced instead through (n,p) or (n,..cap alpha..) reactions with stable isotopes. Mass-separated samples of Nd, Mo, and Se, for example, can be irradiated to produce Pr, Nb, and As radionuclides sufficient for decay scheme studies. The system may also be used for multielement fast-neutron activation analysis because the neutron flux is greater than 2 x 10/sup 11/ n/cm/sup 2/-sec. Single element analyses of Si and O are also possible. Finally, measurements of fast-neutron cross sections producing short-lived activation products can be performed with this system. A description of the rabbit system and instructions for its use are presented in this report.

  14. Design and operation of the wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source.

    PubMed

    Abernathy, D L; Stone, M B; Loguillo, M J; Lucas, M S; Delaire, O; Tang, X; Lin, J Y Y; Fultz, B

    2012-01-01

    The wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source (SNS) is optimized to provide a high neutron flux at the sample position with a large solid angle of detector coverage. The instrument incorporates modern neutron instrumentation, such as an elliptically focused neutron guide, high speed magnetic bearing choppers, and a massive array of (3)He linear position sensitive detectors. Novel features of the spectrometer include the use of a large gate valve between the sample and detector vacuum chambers and the placement of the detectors within the vacuum, both of which provide a window-free final flight path to minimize background scattering while allowing rapid changing of the sample and sample environment equipment. ARCS views the SNS decoupled ambient temperature water moderator, using neutrons with incident energy typically in the range from 15 to 1500 meV. This range, coupled with the large detector coverage, allows a wide variety of studies of excitations in condensed matter, such as lattice dynamics and magnetism, in both powder and single-crystal samples. Comparisons of early results to both analytical and Monte Carlo simulation of the instrument performance demonstrate that the instrument is operating as expected and its neutronic performance is understood. ARCS is currently in the SNS user program and continues to improve its scientific productivity by incorporating new instrumentation to increase the range of science covered and improve its effectiveness in data collection. PMID:22299993

  15. Progress in Development of a Converging Beam Neutron Source for Driving a Sub-Critical Fission Reactor

    SciTech Connect

    Miley, G.H.; Momota, H.; Shaban, Y.; Hora, H.

    2002-07-01

    Several laboratories are studying the possibility of a fission reactor system based on driving a sub-critical assembly using an accelerator-spallation target neutron source. The objective is to effectively eliminate possible criticality and meltdown accidents, increasing plant safety. However, one disadvantage is the large cost projected for the accelerator-driven source. In an ICONE-8 paper we proposed to overcome this problem by use of a Converging Beam Neutron Source (CBNS) to produce 14-MeV D-T fusion neutrons to drive the sub-critical core. [1] The CBNS is analogous to an accelerator-plasma target device with built-in re-circulation of the ions. It offers the unique advantage of being small enough to allow insertion of multiple 'modular' units in fuel channel locations (cf. the large single target used in accelerator-drive designs). As proposed in an ICONE-9 paper, a first important step in development of such systems might be use in low power research reactors. [2] This reduces the neutron source strength requirement to a level only slightly above that obtained with present IEC experiments. Still, a key step for CBNS development is to increase the neutron production efficiency obtained in previous small-scale experiments. To do this we have recently developed a unique RF-driven ion source so that the ion production region can be separated from the main CBNS chamber. This has the combined advantages of allowing ion production at relatively high pressure, while the CBNS chamber can be pumped to ultra-low pressure. Initial experiments with this arrangement are presented here and it is shown that a very favorable scaling to the yields required for research reactor operation are predicted. (authors)

  16. Demonstration of a high-intensity neutron source based on a liquid-lithium target for Accelerator based Boron Neutron Capture Therapy.

    PubMed

    Halfon, S; Arenshtam, A; Kijel, D; Paul, M; Weissman, L; Berkovits, D; Eliyahu, I; Feinberg, G; Kreisel, A; Mardor, I; Shimel, G; Shor, A; Silverman, I; Tessler, M

    2015-12-01

    A free surface liquid-lithium jet target is operating routinely at Soreq Applied Research Accelerator Facility (SARAF), bombarded with a ~1.91MeV, ~1.2mA continuous-wave narrow proton beam. The experiments demonstrate the liquid lithium target (LiLiT) capability to constitute an intense source of epithermal neutrons, for Accelerator based Boron Neutron Capture Therapy (BNCT). The target dissipates extremely high ion beam power densities (>3kW/cm(2), >0.5MW/cm(3)) for long periods of time, while maintaining stable conditions and localized residual activity. LiLiT generates ~3×10(10)n/s, which is more than one order of magnitude larger than conventional (7)Li(p,n)-based near threshold neutron sources. A shield and moderator assembly for BNCT, with LiLiT irradiated with protons at 1.91MeV, was designed based on Monte Carlo (MCNP) simulations of BNCT-doses produced in a phantom. According to these simulations it was found that a ~15mA near threshold proton current will apply the therapeutic doses in ~1h treatment duration. According to our present results, such high current beams can be dissipated in a liquid-lithium target, hence the target design is readily applicable for accelerator-based BNCT. PMID:26300076

  17. The content of 250Cf and 248Cm in 252Cf neutron sources and the effect on the neutron emission rate.

    PubMed

    Roberts, N J; Jones, L N

    2007-01-01

    One of the most common radionuclide neutron sources used for the calibration of detectors is (252)Cf. However, these sources also contain (250)Cf, which is present in the material from which the sources are made, and (248)Cm, which is formed as the daughter of (252)Cf via alpha-decay. Both decay by spontaneous fission with longer half-lives than (252)Cf. Consequently, as the source becomes older, the emission rate does not follow the decay curve of (252)Cf. Fits have been made to emission rate measurements of (252)Cf sources at NPL spanning over 30 y to deduce their (250)Cf and (248)Cm content. The emission rate of a source can be significantly underestimated if the presence of (250)Cf and (248)Cm is not taken into account, and this has been investigated for a typical (252)Cf source. The importance of this problem to other calibration laboratories and users of (252)Cf sources is emphasised. PMID:17502315

  18. An attempt to decrease anisotropic emissions of neutrons from a cylindrical 241Am-Be-encapsulation source.

    PubMed

    Kowatari, M; Tanimura, Y; Yoshizawa, M

    2014-10-01

    An attempt to decrease the anisotropic emissions of neutrons from a cylindrical (241)Am-Be-encapsulated X3 source was conducted with Monte Carlo calculations and experiments. The influence of metal materials and shapes of the external casing to the anisotropy factor were focussed on. Results obtained by calculations using MCNP4C implied that a light and spherical-shaped external casing decreases the anisotropic emission of neutrons. Experimental results using the spherical-shaped aluminium protection case also revealed that the anisotropy factor was close to 1.0 with wide zenith angle ranges. PMID:24218643

  19. Assessment of the neutron emission anisotropy factor of a sealed AmBe source by means of measurements and Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Loreti, S.; Pietropaolo, A.

    2015-10-01

    The neutron emission anisotropy factor of a sealed Americium-Beryllium source is experimentally determined and compared to Monte Carlo simulations. The measurements were done at the Italian Institute for Metrology of Ionizing Radiations using a long counter neutron detector and a "X.3" type AmBe sealed neutron source. Experimental data are compared to simulations performed with the MCNP code where the precise structure of the source is taken into account starting from its technical design. The contributions of the single structural parts are described to point out the effective sources of the emission anisotropy.

  20. Results of the Development of Humanitarian Landmine Detection System by a Compact Fusion Neutron Source and Dual Sensors

    SciTech Connect

    Yoshikawa, Kiyoshi; Masuda, Kai; Takamatsu, Teruhisa; Yamamoto, Yasushi; Toku, Hisayuki; Fujimoto, Takashi; Hotta, Eiki; Yamauchi, Kunihito; Ohnishi, Masami; Osawa, Hodaka; Shiroya, Seiji; Misawa, Tsuyoshi; Takahashi, Yoshiyuki; Kubo, Yoshikazu; Doi, Toshiro

    2009-03-10

    A 5-year task is described on the research and development of the advanced humanitarian landmine detection system by using a compact discharge-type fusion neutron source called IECF (Inertial-Electrostatic Confinement Fusion) device and 3 dual sensors made of BGO and NaI(Tl). With 10{sup 7} D-D neutrons/s stably produced in steady-state mode, H-2.2 MeV, N-5.3, 10.8 MeV {gamma} rays from (n,{gamma}) reaction with hydrogen and nitrogen atoms in the explosives are measured for two kinds of explosives (TNT, RDX), under the conditions of three different buried depths, and soil moistures each. Final probabilities of detection for arid soil are found to be 100% in the present tests. The neutron backscattering method is also found to be efficient.