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Sample records for relative neutronic performance

  1. Neutron spectroscopy, nuclear structure, related topics. Abstracts

    International Nuclear Information System (INIS)

    Sukhovoj, A.M.

    1996-01-01

    Neutron spectroscopy, nuclear structure and related topics are considered. P, T-breaking, neutron beta decay, neutron radiative capture and neutron polarizability are discussed. Reaction with fast neutrons, methodical aspect low-energy fission are considered too

  2. Performance of neutron scattering relative to Diviner2000 for estimating soil water content in salt affected soils

    International Nuclear Information System (INIS)

    Al-Ain, F.; Attar, J.; Hussein, F.

    2007-05-01

    A field experiment was conducted on sandy clay and clayey soils at Deir Ezzor to compare the performance of Neutron Scattering (NS) relative to a capacitance probe (CP), Diviner2000, in our local conditions under saline soils. The effect of soil electrical conductivity (ECe) and bulk density (?b) on the precession, accuracy and sensitivity of the tested equipment s were evaluated. Also, the ability to improve the calibration equation for these equipment s, by including ECe and ?b as independent variables in the equation formula, was studied. The study showed that, Diviner2000 was very sensitive to soil bulk density and electrical conductivity of the soil (i.e. soil salinity) compared to the NS. Multiple non-linear regressions improved the fitting when both parameters (?b and ECe) were included in the equation, even though the correlation coefficient (R2) remained low in the case of Diviner2000.(author)

  3. Design and construction of a triple-axis crystal neutron spectrometer and performance testing by means of measurements of dispersion relations in copper

    International Nuclear Information System (INIS)

    Fuhrmann, C.

    1979-01-01

    The Triple-Axis Crystal Neutron Spectrometer is the best instrument for the study of lattice dynamics, when the neutron inelastic scattering technique is used. Design, construction and operation of a triple-axis crystal neutron spectrometer, whose construction was recently finished at IEA are described. The design principles employed are directed to mechanical simplicity, facility of construction and flexibility in operation, with no adapted components to industrial applications were used in the construction. The operational characteristics of the spectrometer, such as the neutron wavelenght of the incoming beam and the resolution have been determined. With the purpose to check the performance of IEA Triple-Axis Crystal Neutron Spectrometer, dispersion relation curves for copper, at room temperature, have been measured. The frequency of phonons propagating along three major symmetry directions have been determined. The measurements were carried out operating the Triple-Axis Spectrometer in the 'sup(→)Q-constant' mode. An excelent agreement could be observed between the results obtained in the present experiment and the data for copper presented in the literature. This comparison indicates that the IEA Triple-Axis Crystal Neutron Spectrometer is in good operational conditions and is able to perform original experiments. Details on the experimental procedures for the case of a Triple-Axis Spectrometer operating in 'sup(→)Q-constant' mode are also presented. (Author) [pt

  4. Neutronic performance issues for the Spallation Neutron Source moderators

    International Nuclear Information System (INIS)

    Iverson, E.B.; Murphy, B.D.

    2001-01-01

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

  5. Effective source size as related to 252Cf neutron radiography

    International Nuclear Information System (INIS)

    Wada, Nobuo; Enomoto, Shigemasa; Tachikawa, Noboru; Nojiri, Toshiaki.

    1977-01-01

    The effective source size in 252 Cf thermal neutron radiography, relating to its geometrical unsharpness in image formation, is experimentally studied. A neutron radiographic system consists of a 160 μg 252 Cf neutron source, water moderator and divergent cadmium lined collimator. Thermal neutron image detection is performed with using a LiF scintillator and a high speed X-ray film to employ direct exposure method. The modulation transfer function, used for describing image quality, is derived from radiographic image corresponding to a cadmium plate with sharp edge. The modulation transfer function for the system is expressed by the product of the function for both geometrical and inherent unsharpness, and allows isolation of geometrical unsharpness as related to the effective size of the thermal neutron source. It is found to be 80 -- 90% of the collimator inlet diameter. (auth.)

  6. Performance Test of BF3 Neutron Detection System

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yu Sun; Shin, Ho Cheol [KHNP-CRI, Daejeon (Korea, Republic of); Cho, Jin Bok; Oh, Sae Hyun; Ryou, Seok Jean [USERS, Daejeon (Korea, Republic of)

    2015-10-15

    The neutron detecting system of First-of-a-kind plant such an APR1400 at Shin Kori should have been verified in the condition of low operating temperature and pressure of the primary coolant system before receiving the operation license. Auxiliary Ex-core Neutron Flux Monitoring System (AENFMS) is supposed to be installed using BF3 neutron detector in Shin Kori plant. The performance test of AENFMS was conducted to measure neutron sensitivity, moderation ratio and count rate in the same condition with Ex-core Neutron Flux Monitoring System (ENFMS) of APR1400 to verify its detection characteristics in compliance with the functional requirement. Performance test has been conducted for AENFMS of APR1400 to verify BF3 neutron sensitivity, moderation ration of PE, expecting neutron signal count rate from AENFMS, possible extending cable length from detector to pre-amplifier. As a result of measurement, the neutron sensitivity of 34.246±0.168(95%CI)cps/nv, moderation ratio of 11.343±0.039(95%CI) and AENFMS expecting count rate related to ENFMS of 17.8 times are acceptable in compliance with functional requirement, respectively.

  7. Aluminum alloy excellent in neutron absorbing performance

    International Nuclear Information System (INIS)

    Iida, Tetsuya; Tamamura, Tadao; Morimoto, Hiroyuki; Ouchi, Ken-ichiro.

    1987-01-01

    Purpose: To obtain structural materials made of aluminum alloys having favorable neutron absorbing performance and excellent in the performance as structural materials such as processability and strength. Constitution: Powder of Gd 2 O 3 as a gadolinium compound or metal gadolinium is uniformly mixed with the powder of aluminum or aluminum alloy. The amount of the gadolinium compound added is set to 0.1 - 30 % by weight. No sufficient neutron absorbing performance can be obtained if it is less than 0.1 % by weight, whereas the processability and mechanical property of the alloy are degraded if it exceeds 30 % by weight. Further, the grain size is set to less about 50 μm. Further, since the neutron absorbing performance varies greatly if the aluminum powder size exceeds 100 μm, the diameter is set to less than about 100 μm. These mixtures are molded in a hot press. This enables to obtain aimed structural materials. (Takahashi, M.)

  8. A neutron irradiator to perform nuclear activation

    International Nuclear Information System (INIS)

    Zamboni, C. B.; Zahn, G.S.; Figueredo, A. M. G.; Madi, T. F.; Yoriyaz, H.; Lima, R. B.; Shtejer, K.; Dalaqua Jr, L.

    2001-01-01

    The development of appropriate nuclear instrumentation to perform neutron activation analyze (NAA), using thermal and fast neutrons, can be useful to investigate materials outside the reactor premises. Considering this fact, a small size neutron irradiator prototype was developed at IPEN facilities (Instituto de Pesquisas Energeticas e Nucleares - Brazil). Basically, this prototype consists of a cylinder of 1200 mm long and 985 mm diameter (filled with paraffin) with two Am-Be sources (600GBq each) arranged in the longitudinal direction of its geometric center. The material to be irradiated is positioned at a radial direction of the cylinder between the two Am-Be sources. The main advantage of this irradiator is a very stable neutron flux eliminating the use of standard material (measure of the induced activity in the sample by comparative method). This way the process became agile, practical and economic, but quantities at mg levels of samples are necessary to achieve good sensitivity, when the material has a low microscopy neutron cross section. As fast and thermal neutron can be used, the flux distribution, for both, were calculated and the prototype performance is discussed

  9. Study of influence of transport performance of the neutron guide

    International Nuclear Information System (INIS)

    Li Xinxi; Wang Yan; Huang Chaoqiang; Chen Bo; Chen Liang

    2009-01-01

    For the sake of improving the performance of the neutron scattering instrument, usually we need use the neutron guide, it's very important to select the right type and optimizing of neutron guide. The papers calculate the focus neutron guide and the single channel neutron guide by numeric method. The results shows that the choice of neutron guide should consult the resolution requirement of neutron scattering instrument, and the length of the neutron guide should be optimized. The calculation results can be the theoretical reference for the design of neutron scattering instrument. (authors)

  10. Simulation of merging neutron stars in full general relativity

    International Nuclear Information System (INIS)

    Shibata, M.

    2001-01-01

    We have performed 3D numerical simulations for merger of equal mass binary neutron stars in full general relativity. We adopt a Γ-law equation of state in the form P = (Γ - 1)ρε where P, ρ, ε and Γ are the pressure, rest mass density, specific internal energy, and the adiabatic constant. As initial conditions, we adopt models of irrotational binary neutron stars in a quasiequilibrium state. Simulations have been carried out for a wide range of Γ and compactness of neutron stars, paying particular attention to the final product and gravitational waves. We find that the final product depends sensitively on the initial compactness of the neutron stars: In a merger between sufficiently compact neutron stars, a black hole is formed in a dynamical timescale. As the compactness is decreased, the formation timescale becomes longer and longer. It is also found that a differentially rotating massive neutron star is formed instead of a black hole for less compact binary cases. In the case of black hole formation, the disk mass around the black hole appears to be very small; less than 1% of the total rest mass. It is indicated that waveforms of high-frequency gravitational waves after merger depend strongly on the compactness of neutron stars before the merger. We point out importance of detecting such gravitational waves of high frequency to constrain the maximum allowed mass of neutron stars. (author)

  11. Relative neutronic performance of proposed high-density dispersion fuels in water-moderated and D2O-reflected research reactors

    International Nuclear Information System (INIS)

    Bretscher, M.M.; Matos, J.E.; Snelgrove, J.L.

    1996-01-01

    This paper provides an overview of the neutronic performance of an idealized research reactor using several high density LEU fuels that are being developed by the RERTR program. High-density LEU dispersion fuels are needed for new and existing high-performance research reactors and to extend the lifetime of fuel elements in other research reactors. This paper discusses the anticipated neutronic behavior of proposed advanced fuels containing dispersions of U 3 Si 2 , UN, U 2 Mo and several uranium alloys with Mo, or Zr and Nb. These advanced fuels are ranked based on the results of equilibrium depletion calculations for a simplified reactor model having a small H 2 O-cooled core and a D 2 O reflector. Plans have been developed to fabricate and irradiate several uranium alloy dispersion fuels in order to test their stability and compatibility with the matrix material and to establish practical loading limits

  12. Relative neutronic performance of proposed high-density dispersion fuels in water-moderated and D2O-reflected research reactors

    International Nuclear Information System (INIS)

    Bretscher, M.M.; Matos, J.E.; Snelgrove, J.L.

    1996-01-01

    This paper provides an overview of the neutronic performance of an idealized research reactor using several high density Leu fuels that are being developed by the Rarita program. High-density Leu dispersion fuels are needed for new and existing high-performance research reactors and to extend the lifetime of fuel elements in other research reactors. This paper discusses the anticipated neutronic behavior of proposed advanced fuels containing dispersions of U 3 Si 2 , UN, U 2 Mo and several uranium alloys with Mo, or Zr and Nb. These advanced fuels are ranked based on the results of equilibrium depletion calculations for a simplified reactor model having a small H 2 O-cooled core and a D 2 O reflector. Plans have been developed to fabricate and irradiate several uranium alloy dispersion fuels in order to test their stability and compatibility with the matrix material and to establish practical loading limits. (author)

  13. Materials performance experience at spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, W.F. [Los Alamos National Laboratory, NM (United States)

    1995-10-01

    There is a growing, but not yet substantial, data base for materials performance at spallation neutron sources. Specially designed experiments using medium energy protons (650 MeV) have been conducted at the Proton Irradiation Experiment (PIREX) facility at the Swiss Nuclear Institute accelerator (SIN). Specially designed experiments using 760-800 MeV copper target have been completed at the Los Alamos Spallation Radiation Effects Facility (LASREF) at Los Alamos Meson Physics Facility (LAMPF). An extensive material testing program was initiated at LASREF in support of the German spallation neutron source (SNQ) project, before it terminated in 1985.

  14. Neutron performance analysis for ESS target proposal

    International Nuclear Information System (INIS)

    Magán, M.; Terrón, S.; Thomsen, K.; Sordo, F.; Perlado, J.M.; Bermejo, F.J.

    2012-01-01

    In the course of discussing different target types for their suitability in the European Spallation Source (ESS) one main focus was on neutronics' performance. Diverse concepts have been assessed baselining some preliminary engineering and geometrical details and including some optimization. With the restrictions and resulting uncertainty imposed by the lack of detailed designs optimizations at the time of compiling this paper, the conclusion drawn is basically that there is a little difference in the neutronic yield of the investigated targets. Other criteria like safety, environmental compatibility, reliability and cost will thus dominate the choice of an ESS target.

  15. A proposal on evaluation method of neutron absorption performance to substitute conventional neutron attenuation test

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Je Hyun; Shim, Chang Ho [Dept. of Nuclear Engineering, Hanyang University, Seoul (Korea, Republic of); Kim, Sung Hyun [Nuclear Fuel Cycle Waste Treatment Research Division, Research Reactor Institute, Kyoto University, Osaka (Japan); Choe, Jung Hun; Cho, In Hak; Park, Hwan Seo [Ionizing Radiation Center, Nuclear Fuel Cycle Waste Treatment Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Hyun Seo; Kim, Jung Ho; Kim, Yoon Ho [Ionizing Radiation Center, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2016-12-15

    For a verification of newly-developed neutron absorbers, one of guidelines on the qualification and acceptance of neutron absorbers is the neutron attenuation test. However, this approach can cause a problem for the qualifications that it cannot distinguish how the neutron attenuates from materials. In this study, an estimation method of neutron absorption performances for materials is proposed to detect both direct penetration and back-scattering neutrons. For the verification of the proposed method, MCNP simulations with the experimental system designed in this study were pursued using the polyethylene, iron, normal glass and the vitrified form. The results show that it can easily test neutron absorption ability using single absorber model. Also, from simulation results of single absorber and double absorbers model, it is verified that the proposed method can evaluate not only the direct thermal neutrons passing through materials, but also the scattered neutrons reflected to the materials. Therefore, the neutron absorption performances can be accurately estimated using the proposed method comparing with the conventional neutron attenuation test. It is expected that the proposed method can contribute to increase the reliability of the performance of neutron absorbers.

  16. A proposal on evaluation method of neutron absorption performance to substitute conventional neutron attenuation test

    International Nuclear Information System (INIS)

    Kim, Je Hyun; Shim, Chang Ho; Kim, Sung Hyun; Choe, Jung Hun; Cho, In Hak; Park, Hwan Seo; Park, Hyun Seo; Kim, Jung Ho; Kim, Yoon Ho

    2016-01-01

    For a verification of newly-developed neutron absorbers, one of guidelines on the qualification and acceptance of neutron absorbers is the neutron attenuation test. However, this approach can cause a problem for the qualifications that it cannot distinguish how the neutron attenuates from materials. In this study, an estimation method of neutron absorption performances for materials is proposed to detect both direct penetration and back-scattering neutrons. For the verification of the proposed method, MCNP simulations with the experimental system designed in this study were pursued using the polyethylene, iron, normal glass and the vitrified form. The results show that it can easily test neutron absorption ability using single absorber model. Also, from simulation results of single absorber and double absorbers model, it is verified that the proposed method can evaluate not only the direct thermal neutrons passing through materials, but also the scattered neutrons reflected to the materials. Therefore, the neutron absorption performances can be accurately estimated using the proposed method comparing with the conventional neutron attenuation test. It is expected that the proposed method can contribute to increase the reliability of the performance of neutron absorbers

  17. Eurados trial performance test for neutron personal dosimetry

    DEFF Research Database (Denmark)

    Bordy, J.M.; Stadtmann, H.; Ambrosi, P.

    2001-01-01

    This paper reports on the results of a neutron trial performance test sponsored by the European Commission and organised by EURADOS. As anticipated, neutron dosimetry results were very dependent on the dosemeter type and the dose calculation algorithm. Fast neutron fields were generally well...

  18. Performance of an elliptically tapered neutron guide

    International Nuclear Information System (INIS)

    Muehlbauer, Sebastian; Stadlbauer, Martin; Boeni, Peter; Schanzer, Christan; Stahn, Jochen; Filges, Uwe

    2006-01-01

    Supermirror coated neutron guides are used at all modern neutron sources for transporting neutrons over large distances. In order to reduce the transmission losses due to multiple internal reflection of neutrons, ballistic neutron guides with linear tapering have been proposed and realized. However, these systems suffer from an inhomogeneous illumination of the sample. Moreover, the flux decreases significantly with increasing distance from the exit of the neutron guide. We propose using elliptically tapered guides that provide a more homogeneous phase space at the sample position as well as a focusing at the sample. Moreover, the design of the guide system is simplified because ellipses are simply defined by their long and short axes. In order to prove the concept we have manufactured a doubly focusing guide and investigated its properties with neutrons. The experiments show that the predicted gains using the program package McStas are realized. We discuss several applications of elliptic guides in various fields of neutron physics

  19. 8-group relative delayed neutron yields for monoenergetic neutron induced fission of 239Pu

    International Nuclear Information System (INIS)

    Piksaikin, V.M.; Kazakov, L.E.; Isaev, S.G.; Korolev, G.G.; Roshchenko, V.A.; Tertychnyj, R.G

    2002-01-01

    The energy dependence of the relative yield of delayed neutrons in an 8-group model representation was obtained for monoenergetic neutron induced fission of 239 Pu. A comparison of this data with the available experimental data by other authors was made in terms of the mean half-life of the delayed neutron precursors. (author)

  20. Neutron shielding performance of water-extended polyester

    International Nuclear Information System (INIS)

    Vega Carrillo, H.R.; Manzanares-Acuna, E.; Hernandez-Davila, V.M.; Vega Carrillo, H.R.; Hernandez-Davila, V.M.; Gallego, E.; Lorente, A.

    2006-01-01

    A Monte Carlo study to determine the shielding features to neutrons of water-extended polyester (WEP) was carried out. Materials with low atomic number are predominantly used for neutron shielding because these materials effectively attenuate neutrons, mainly through elastic and inelastic collisions. In addition to neutron attenuation properties, other desirable properties for neutron shielding materials include mechanical strength, stability, low cost, and ease of handling. During the selection of materials to design a neutron shield, prompt gamma production as well as radionuclide induced by neutron activation must be considered. In this investigation the Monte Carlo method (MCNP code) was used to evaluate the performance of a water-extended polyester shield designed for the transportation, storage, and use of a 252 Cf isotopic neutron source, for comparison the calculations were extended to water shielding, the bare source in vacuum and in air. (authors)

  1. Neutron shielding performance of water-extended polyester

    International Nuclear Information System (INIS)

    Vega Carrillo, H.R.; Manzanares-Acuna, E.; Hernandez-Davila, V.M.; Vega Carrillo, H.R.; Gallegoc, E.; Lorentec, A.; Hernandez-Davila, V.M.

    2006-01-01

    A Monte Carlo study to determine the shielding features to neutrons of water-extended polyester was carried out. Materials with low atomic number are predominantly used for neutron shielding because these materials effectively attenuate neutrons, mainly through elastic and inelastic collisions. In addition to neutron attenuation properties, other desirable properties for neutron shielding materials include mechanical strength, stability, low cost, and ease of handling. During the selection of materials to design a neutron shield, prompt gamma production as well as radionuclide induced by neutron activation must be considered. In this investigation the Monte Carlo method (M.C.N.P. code) was used to evaluate the performance of a water-extended polyester shield designed for the transportation, storage, and use of a 252 Cf isotopic neutron source, for comparison the calculations were extended to water shielding, the bare source in vacuum and in air. (authors)

  2. Neutron shielding performance of water-extended polyester

    Energy Technology Data Exchange (ETDEWEB)

    Vega Carrillo, H.R.; Manzanares-Acuna, E.; Hernandez-Davila, V.M. [Zacatecas Univ. Autonoma, Nuclear Studies (Mexico); Vega Carrillo, H.R.; Hernandez-Davila, V.M. [Zacatecas Univ. Autonoma, Electric Engineering Academic Units (Mexico); Gallego, E.; Lorente, A. [Madrid Univ. Politecnica, cNuclear Engineering Department (Mexico)

    2006-07-01

    A Monte Carlo study to determine the shielding features to neutrons of water-extended polyester (WEP) was carried out. Materials with low atomic number are predominantly used for neutron shielding because these materials effectively attenuate neutrons, mainly through elastic and inelastic collisions. In addition to neutron attenuation properties, other desirable properties for neutron shielding materials include mechanical strength, stability, low cost, and ease of handling. During the selection of materials to design a neutron shield, prompt gamma production as well as radionuclide induced by neutron activation must be considered. In this investigation the Monte Carlo method (MCNP code) was used to evaluate the performance of a water-extended polyester shield designed for the transportation, storage, and use of a {sup 252}Cf isotopic neutron source, for comparison the calculations were extended to water shielding, the bare source in vacuum and in air. (authors)

  3. Direct neutron capture and related mechanisms

    International Nuclear Information System (INIS)

    Lynn, J.E.; Raman, S.

    1990-01-01

    We consider the evidence for the role of direct and related mechanisms in neutron capture at low and medium energies. Firstly, we compare the experimental data on the thermal neutron cross sections for El transitions in light nuclei with careful estimates of direct capture. Over the full range of light nuclei with small cross sections direct capture is found to be the predominant mechanism, in some cases being remarkable accurate, but in a few showing evidence for collective effects. When resonance effects become substantial there is evidence for an important contribution from the closely related valence mechanism, but full agreement with the data in such cases appears to require the introduction of a more generalised valence model. The possibility of direct and valence mechanisms playing a role in M1 capture is studied, and it is concluded that in light nuclei at relatively low gamma ray energies, it does indeed play some role. In heavier nuclei it appears that the evidence, especially from the correlations between E1 and M1 transitions to the same final states, favours the hypothesis that the main transition strength is governed by the M1 giant resonance. 31 refs., 2 tabs

  4. The measurement of neutron and neutron induced photon spectra in fusion reactor related assemblies

    CERN Document Server

    Unholzer, S; Klein, H; Seidel, K

    2002-01-01

    The spectral neutron and photon fluence (or flux) measured outside and inside of assemblies related to fusion reactor constructions are basic quantities of fusion neutronics. The comparison of measured spectra with the results of MCNP neutron and photon transport calculations allows a crucial test of evaluated nuclear data as generally used in fusion applications to be carried out. The experiments concern mixed neutron/photon fields with about the same intensity of the two components. An NE-213 scintillation spectrometer, well described by response matrices for both neutrons and photons, is used as proton-recoil and Compton spectrometer. The experiments described here in more detail address the background problematic of two applications, an iron benchmark experiment with an ns-pulsed neutron source and a deep penetration mock-up experiment for the investigation of the ITER in-board shield system. The measured spectral neutron and photon fluences are compared with spectra calculated with the MCNP code on the b...

  5. Performance of a thermal neutron radiographic system using imaging plates

    International Nuclear Information System (INIS)

    Silvani, Maria Ines; Almeida, Gevaldo L. de; Furieri, Rosanne; Lopes, Ricardo T.

    2009-01-01

    A performance evaluation of a neutron radiographic system equipped with a thermal neutron sensitive imaging plate has been undertaken. It includes the assessment of spatial resolution, linearity, dynamic range and the response to exposure time, as well as a comparison of these parameters with the equivalent ones for neutron radiography employing conventional films and a gadolinium foil as converter. The evaluation and comparison between the radiographic systems have been performed at the Instituto de Engenharia Nuclear - CNEN, using the Argonauta Reactor as source of thermal neutrons and a commercially available imaging plate reader. (author)

  6. Performance evaluation of METAMIC neutron absorber in spent fuel storage rack

    Directory of Open Access Journals (Sweden)

    Kiyoung Kim

    2018-06-01

    Full Text Available High-density spent fuel (SF storage racks have been installed to increase SF pool capacity. In these SF racks, neutron absorber materials were placed between fuel assemblies allowing the storage of fuel assemblies in close proximity to one another. The purpose of the neutron absorber materials is to preclude neutronic coupling between adjacent fuel assemblies and to maintain the fuel in a subcritical storage condition. METAMIC neutron absorber has been used in high-density storage racks. But, neutron absorber materials can be subject to severe conditions including long-term exposure to gamma radiation and neutron radiation. Recently, some of them have experienced degradation, such as white spots on the surface. Under these conditions, the material must continue to serve its intended function of absorbing neutrons. For the first time in Korea, this article uses a neutron attenuation test to examine the performance of METAMIC surveillance coupons. Also, scanning electron microscope analysis was carried out to verify the white spots that were detected on the surface of METAMIC. In the neutron attenuation test, there was no significant sign of boron loss in most of the METAMIC coupons, but the coupon with white spots had relatively less B-10 content than the others. In the scanning electron microscope analysis, corrosion material was detected in all METAMIC coupons. Especially, it was confirmed that the coupon with white spots contains much more corrosion material than the others. Keywords: Blister, Criticality, METAMIC, Neutron Absorber, Neutron Attenuation Test, Scanning Electron Microscope

  7. METHODS OF ASSESSMENT OF THE RELATIVE BIOLOGICAL EFFECTIVENESS OF NEUTRONS IN NEUTRON THERAPY

    Directory of Open Access Journals (Sweden)

    V. A. Lisin

    2017-01-01

    Full Text Available The relative biological effectiveness (RBE of fast neutrons is an important factor influencing the quality of neutron therapy therefore, the assessment of RBE is of great importance. Experimental and clinical studies as well as different mathematical and radiobiological models are used for assessing RBE. Research is conducted for neutron sources differing in the method of producing particles, energy and energy spectrum. Purpose: to find and analyze the dose-dependence of fast neutron RBE in neutron therapy using the U-120 cyclotron and NG-12I generator. Material and methods: The optimal method for assessing the relative biological effectiveness of neutrons for neutron therapy was described. To analyze the dependence of the RBE on neutron dose, the multi-target model of cell survival was applied. Results: The dependence of the RBE of neutrons produced from the U-120 cyclotron and NG-120 generator on the dose level was found for a single irradiation of biological objects. It was shown that the function of neutron dose was consistent with similar dependencies found by other authors in the experimental and clinical studies.

  8. ISINN-3. Neutron spectroscopy, nuclear structure, related topics

    International Nuclear Information System (INIS)

    1995-01-01

    The proceedings contain the materials presented at the Third International Seminar on Neutron-Nucleus Interactions (ISINN-3) dealing with the problems of neutron spectroscopy, nuclear structure and related topics. The Seminar took place in Dubna on April 26-28, 1995. Over 100 scientists from Belgium, Bulgaria, Czech Republic, Germany, Japan, Latvia, Mexico, Poland, Slovakia, Ukraine, USA and from more than 10 Russian research institutes took part in the Seminar. The Seminar is dedicated to the memory of the founder of the Neutron Physics Laboratory of JINR, the famous soviet scientist Professor Fedor L. Shapiro, whose 80th anniversary is being observed. The main problems discussed are the following: fundamental interactions and symmetries in neutron-induced reactions, fundamental properties of the neutron, properties of excited nuclei after neutron capture and some other ones. Special emphasis is laid upon γ decay and neutron induced nuclear fission as well as upon the methodical aspects of new experiments

  9. Neutron metrology file NMF-90. An integrated database for performing neutron spectrum adjustment calculations

    International Nuclear Information System (INIS)

    Kocherov, N.P.

    1996-01-01

    The Neutron Metrology File NMF-90 is an integrated database for performing neutron spectrum adjustment (unfolding) calculations. It contains 4 different adjustment codes, the dosimetry reaction cross-section library IRDF-90/NMF-G with covariances files, 6 input data sets for reactor benchmark neutron fields and a number of utility codes for processing and plotting the input and output data. The package consists of 9 PC HD diskettes and manuals for the codes. It is distributed by the Nuclear Data Section of the IAEA on request free of charge. About 10 MB of diskspace is needed to install and run a typical reactor neutron dosimetry unfolding problem. (author). 8 refs

  10. Albedo neutron dosimetry in Germany: regulations and performance

    International Nuclear Information System (INIS)

    Luszik-Bhadra, M.; Zimbal, A.; Busch, F.; Jordan, M.; Eichelberger, A.; Engelhardt, J.; Martini, E.; Figel, M.; Haninger, T.; Frasch, G.; Guenther, K.; Seifert, R.; Rimpler, A.

    2014-01-01

    Personal neutron dosimetry has been performed in Germany using albedo dosemeters for >20 y. This paper describes the main principles, the national standards, regulations and recommendations, the quality management and the overall performance, giving some examples. (authors)

  11. Performance of neutron polarimeter SMART-NPOL

    International Nuclear Information System (INIS)

    Noji, S.; Miki, K.; Yako, K.; Kawabata, T.; Kuboki, H.; Sakai, H.; Sekiguchi, K.; Suda, K.

    2007-01-01

    The neutron polarimeter SMART-NPOL has been constructed at the RIKEN Accelerator Research Facility for measuring polarization correlations of proton-neutron systems. The SMART-NPOL system consists of 12 parallel neutron counter planes of two dimensionally position-sensitive plastic scintillators with a size of 60x60x3.0cm 3 . Polarimetry measurements were made using the analyzing power of the H1(n-vector,n)H1 reaction occurring in the plastic scintillators. The effective analyzing power of SMART-NPOL was measured with polarized neutrons from the zero-degree Li6(d-vector,n-vector) reaction with an incident deuteron energy of 135MeV/A. The effective analyzing power thus obtained was 0.26±0.01 stat ±0.03 syst and the double scattering efficiency was 1.1x10 -3

  12. Neutronic performances of the MEGAPIE target

    Energy Technology Data Exchange (ETDEWEB)

    Panebianco, S.; Bringer, O.; Chabod, S.; Dupont, E.; Letourneau, A. [CEA Saclay, Dept. d' Astrophysique de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee (DSM/DAPNIA/SPhN), 91- Gif sur Yvette (France); Beauvais, P.; Lotrus, P.; Molinie, F.; Toussaint, J.Ch. [CEA Saclay, Dept. d' Astrophysique de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee (DSM/DAPNIA), 91- Gif sur Yvette (France); Chartier, F. [CEA Saclay, Dept. de Physico-Chimie (DEN/DPC/SECR), 91 - Gif sur Yvette (France); Oriol, L. [CEA Cadarache, Dept. d' Etudes des Reacteurs (DEN/DER/SPEX), 13 - Saint Paul lez Durance (France)

    2008-07-01

    The MEGAPIE project is a key experiment on the road to Accelerator Driven Systems and it provides the scientific community with unique data on the behavior of a liquid lead-bismuth spallation target under realistic and long term irradiation conditions. The neutronic of such target is of course of prime importance when considering its final destination as an intense neutron source. This is the motivation to characterize the inside neutron flux of the target in operation. A complex detector, made of 8 'micro' fission-chambers, has been built and installed in the core of the target, few tens of centimeters from the proton/Pb-Bi interaction zone. This detector is designed to measure the absolute neutron flux inside the target, to give its spatial distribution and to correlate its temporal variations with the beam intensity. Moreover, integral information on the neutron energy distribution as a function of the position along the beam axis could be extracted, giving integral constraints on the neutron production models implemented in transport codes such as MCNPX. (authors)

  13. Performance of neutron kinetics models for ADS transient analyses

    International Nuclear Information System (INIS)

    Rineiski, A.; Maschek, W.; Rimpault, G.

    2002-01-01

    Within the framework of the SIMMER code development, neutron kinetics models for simulating transients and hypothetical accidents in advanced reactor systems, in particular in Accelerator Driven Systems (ADSs), have been developed at FZK/IKET in cooperation with CE Cadarache. SIMMER is a fluid-dynamics/thermal-hydraulics code, coupled with a structure model and a space-, time- and energy-dependent neutronics module for analyzing transients and accidents. The advanced kinetics models have also been implemented into KIN3D, a module of the VARIANT/TGV code (stand-alone neutron kinetics) for broadening application and for testing and benchmarking. In the paper, a short review of the SIMMER and KIN3D neutron kinetics models is given. Some typical transients related to ADS perturbations are analyzed. The general models of SIMMER and KIN3D are compared with more simple techniques developed in the context of this work to get a better understanding of the specifics of transients in subcritical systems and to estimate the performance of different kinetics options. These comparisons may also help in elaborating new kinetics models and extending existing computation tools for ADS transient analyses. The traditional point-kinetics model may give rather inaccurate transient reaction rate distributions in an ADS even if the material configuration does not change significantly. This inaccuracy is not related to the problem of choosing a 'right' weighting function: the point-kinetics model with any weighting function cannot take into account pronounced flux shape variations related to possible significant changes in the criticality level or to fast beam trips. To improve the accuracy of the point-kinetics option for slow transients, we have introduced a correction factor technique. The related analyses give a better understanding of 'long-timescale' kinetics phenomena in the subcritical domain and help to evaluate the performance of the quasi-static scheme in a particular case. One

  14. Performance modeling of parallel algorithms for solving neutron diffusion problems

    International Nuclear Information System (INIS)

    Azmy, Y.Y.; Kirk, B.L.

    1995-01-01

    Neutron diffusion calculations are the most common computational methods used in the design, analysis, and operation of nuclear reactors and related activities. Here, mathematical performance models are developed for the parallel algorithm used to solve the neutron diffusion equation on message passing and shared memory multiprocessors represented by the Intel iPSC/860 and the Sequent Balance 8000, respectively. The performance models are validated through several test problems, and these models are used to estimate the performance of each of the two considered architectures in situations typical of practical applications, such as fine meshes and a large number of participating processors. While message passing computers are capable of producing speedup, the parallel efficiency deteriorates rapidly as the number of processors increases. Furthermore, the speedup fails to improve appreciably for massively parallel computers so that only small- to medium-sized message passing multiprocessors offer a reasonable platform for this algorithm. In contrast, the performance model for the shared memory architecture predicts very high efficiency over a wide range of number of processors reasonable for this architecture. Furthermore, the model efficiency of the Sequent remains superior to that of the hypercube if its model parameters are adjusted to make its processors as fast as those of the iPSC/860. It is concluded that shared memory computers are better suited for this parallel algorithm than message passing computers

  15. ISINN-2. Neutron spectroscopy, nuclear structure and related topics

    International Nuclear Information System (INIS)

    1994-01-01

    The proceedings contain the materials presented at the Second International Seminar on Neutron-Nucleus Interactions (ISINN-2) dealing with the problems of neutron spectroscopy, nuclear structure and related topics. The Seminar took place in Dubna on April 26-28, 1994. Over 120 scientists from Belgium, Bulgaria, Czech Republic, Germany, Holland, Italy, Japan, Latvia, Mexico, Poland, Slovakia, Slovenia, Ukraine, US and about 10 Russian research institutes took part in the Seminar. The main problems discussed are the following: P-odd and P-even angular correlation and T-reversal invariance in neutron reactions, nuclear structure investigations by neutron capture, the mechanism of neutron reactions, nuclear fission processes, as well as neutron data for nuclear astrophysics

  16. Time-dependent pseudo-reciprocity relations in neutronics

    International Nuclear Information System (INIS)

    Modak, R.S.; Sahni, D.C.

    2002-01-01

    Earlier, certain reciprocity-like relations have been shown to hold in some restricted steady state cases in neutron diffusion and transport theories. Here, the possibility of existence of similar relations in time-dependent situations is investigated

  17. Massively parallel performance of neutron transport response matrix algorithms

    International Nuclear Information System (INIS)

    Hanebutte, U.R.; Lewis, E.E.

    1993-01-01

    Massively parallel red/black response matrix algorithms for the solution of within-group neutron transport problems are implemented on the Connection Machines-2, 200 and 5. The response matrices are dericed from the diamond-differences and linear-linear nodal discrete ordinate and variational nodal P 3 approximations. The unaccelerated performance of the iterative procedure is examined relative to the maximum rated performances of the machines. The effects of processor partitions size, of virtual processor ratio and of problems size are examined in detail. For the red/black algorithm, the ratio of inter-node communication to computing times is found to be quite small, normally of the order of ten percent or less. Performance increases with problems size and with virtual processor ratio, within the memeory per physical processor limitation. Algorithm adaptation to courser grain machines is straight-forward, with total computing time being virtually inversely proportional to the number of physical processors. (orig.)

  18. Performance review: neutron hodoscope at TREAT

    International Nuclear Information System (INIS)

    Stanford, G.S.; DeVolpi, A.; Fink, C.L.; Regis, J.P.; Rhodes, E.A.; Stewart, R.R.

    1976-01-01

    The current fuel-motion-detection capabilities of the neutron hodoscopes at TREAT are outlined and discussed, including such topics as spatial and fuel-density resolution, dynamic range, and corrections for detector dead time and supralinearity. Capabilities and analytical techniques are illustrated with examples from several of the power-transient experiments that have been run in the TREAT reactor

  19. The neutronic performance of solid-target alternatives for SINQ

    International Nuclear Information System (INIS)

    Atchison, F.

    1991-01-01

    The results from calculations of the neutronic performance of three possible 'solid' targets and that of the current version of the liquid Pb-Bi target are presented. Two are 'conventional' transverse cooled plate structures, one using tantalum, the other tungsten. The third is a Pb-shot based pebble-bed design. Some general results on the effect of neutron absorption on the performance of the Pebble-bed target are given. (author)

  20. Practical implications of neutron survey instrument performance

    International Nuclear Information System (INIS)

    Tanner, R. J.; Bartlett, D. T.; Hager, I. G.; Jones, I. N.; Molinos, C.; Roberts, N. J.; Taylor, G. C.; Thomas, D. J.

    2004-01-01

    Improvements have been made to the Monte Carlo modelling used to calculate the response of the neutron survey instruments most commonly used in the UK, for neutron energies up to 20 MeV. The improved modelling of the devices includes the electronics and battery pack, allowing better calculations of both the energy and angle dependence of response. These data are used to calculate the response of the instruments in rotationally and fully isotropic, as well as unidirectional fields. Experimental measurements with radionuclide sources and monoenergetic neutron fields have been, and continue to be made, to test the calculated response characteristics. The enhancements to the calculations have involved simulation of the sensitivity of the response to variations in instrument manufacture, and will include the influence of the user and floor during measurements. The practical implications of the energy and angle dependence of response, variations in manufacture, and the influence of the user are assessed by folding the response characteristics with workplace energy and direction distributions. (authors)

  1. How to polarise all neutrons in one beam: a high performance polariser and neutron transport system

    Science.gov (United States)

    Rodriguez, D. Martin; Bentley, P. M.; Pappas, C.

    2016-09-01

    Polarised neutron beams are used in disciplines as diverse as magnetism,soft matter or biology. However, most of these applications often suffer from low flux also because the existing neutron polarising methods imply the filtering of one of the spin states, with a transmission of 50% at maximum. With the purpose of using all neutrons that are usually discarded, we propose a system that splits them according to their polarisation, flips them to match the spin direction, and then focuses them at the sample. Monte Carlo (MC) simulations show that this is achievable over a wide wavelength range and with an outstanding performance at the price of a more divergent neutron beam at the sample position.

  2. Uncertainties related to numerical methods for neutron spectra unfolding

    International Nuclear Information System (INIS)

    Glodic, S.; Ninkovic, M.; Adarougi, N.A.

    1987-10-01

    One of the often used techniques for neutron detection in radiation protection utilities is the Bonner multisphere spectrometer. Besides its advantages and universal applicability for evaluating integral parameters of neutron fields in health physics practices, the outstanding problems of the method are data analysis and the accuracy of the results. This paper briefly discusses some numerical problems related to neutron spectra unfolding, such as uncertainty of the response matrix as a source of error, and the possibility of real time data reduction using spectrometers. (author)

  3. High-performance instruments in neutron arena of JHP. Preliminary version

    International Nuclear Information System (INIS)

    Furusaka, M.; Itoh, S.; Otomo, T.; Arai, M.

    1996-05-01

    This report is a preliminary report of high-performance instruments in neutron arena of JHP (Japan Hadron Project). This report consists of as follows; neutron intensity of neutron arena, development of neutron sources in neutron arena, experimental devices and instrumentation. (J.P.N.)

  4. Neutron Exposures in Human Cells: Bystander Effect and Relative Biological Effectiveness

    Science.gov (United States)

    Seth, Isheeta; Schwartz, Jeffrey L.; Stewart, Robert D.; Emery, Robert; Joiner, Michael C.; Tucker, James D.

    2014-01-01

    Bystander effects have been observed repeatedly in mammalian cells following photon and alpha particle irradiation. However, few studies have been performed to investigate bystander effects arising from neutron irradiation. Here we asked whether neutrons also induce a bystander effect in two normal human lymphoblastoid cell lines. These cells were exposed to fast neutrons produced by targeting a near-monoenergetic 50.5 MeV proton beam at a Be target (17 MeV average neutron energy), and irradiated-cell conditioned media (ICCM) was transferred to unirradiated cells. The cytokinesis-block micronucleus assay was used to quantify genetic damage in radiation-naïve cells exposed to ICCM from cultures that received 0 (control), 0.5, 1, 1.5, 2, 3 or 4 Gy neutrons. Cells grown in ICCM from irradiated cells showed no significant increase in the frequencies of micronuclei or nucleoplasmic bridges compared to cells grown in ICCM from sham irradiated cells for either cell line. However, the neutron beam has a photon dose-contamination of 5%, which may modulate a neutron-induced bystander effect. To determine whether these low doses of contaminating photons can induce a bystander effect, cells were irradiated with cobalt-60 at doses equivalent to the percent contamination for each neutron dose. No significant increase in the frequencies of micronuclei or bridges was observed at these doses of photons for either cell line when cultured in ICCM. As expected, high doses of photons induced a clear bystander effect in both cell lines for micronuclei and bridges (pbystander effect in these cells. Finally, neutrons had a relative biological effectiveness of 2.0±0.13 for micronuclei and 5.8±2.9 for bridges compared to cobalt-60. These results may be relevant to radiation therapy with fast neutrons and for regulatory agencies setting standards for neutron radiation protection and safety. PMID:24896095

  5. A High Resolution Spallation Driven Facility at the CERN-PS to Measure Neutron Cross Sections in the Interval from 1 eV to 250 MeV a Relative Performance Assessment

    CERN Document Server

    Rubbia, Carlo; Bouvet-Bensimon, D; Buono, S; Cappi, R; Cennini, P; Gelès, C; Goulas, I; Kadi, Y; Pavlopoulos, P; Revol, Jean Pierre Charles; Tzima, A; Vlachoudis, V

    1998-01-01

    In the proposed facility with 24 GeV PS beam on a Lead target, the number of produced neutrons exceeds 760 per proton. In comparison, with a LINAC (GELINA) one currently obtains only about 0.05 neutrons per electron of about 100 MeV. An additional factor of 2.5 for the CERN facility is due to the strong, forward peaking of the neutron flux, arising from the high proton energy and corresponding longitudinal boost. This huge factor in neutron yield per incident particle, namely 2.5 x 760/0.05 = 3.8 x 10^4, is only partially off-set by the higher, time averaged current of the LINAC e.g. 100 mA vs . 2 mA of the CERN-PS. Therefore the useful, initial neutron rate at the CERN facility is about three orders of magnitude larger than in the most performing electron LINAC’s, GELINA in Belgium and ORELLA in the US. The time duration of the PS pulse is presently Deltat|_r.m.s.=13.5 ns and we believe it could be reduced to Deltat|_r.m.s.= 6.75 ns. The electron LINAC has much shorter pulses Deltat| _r.m.s.= 1 ns, to which...

  6. Neutron detection performance of silicon carbide and diamond detectors with incomplete charge collection properties

    Energy Technology Data Exchange (ETDEWEB)

    Hodgson, M., E-mail: michael.hodgson@becq.co.uk [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Lohstroh, A.; Sellin, P. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Thomas, D. [NPL, Teddington TW11 0LW (United Kingdom)

    2017-03-01

    The benefits of neutron detection and spectroscopy with carbon based, wide band gap, semiconductor detectors have previously been discussed within the literature. However, at the time of writing there are still limitations with these detectors related to availability, cost, size and perceived quality. This study demonstrates that lower quality materials—indicated by lower charge collection efficiency (CCE), poor resolution and polarisation effect—available at wafer scale and lower cost, can fulfil requirements for fast neutron detection and spectroscopy for fluxes over several orders of magnitude, where only coarse energy discrimination is required. In this study, a single crystal diamond detector (D-SC, with 100% CCE), a polycrystalline diamond (D-PC, with ≈4% CCE) and semi-insulating silicon carbide (SiC-SI, with ≈35% CCE) have been compared for alpha and fast neutron performance. All detectors demonstrated alpha induced polarisation effects in the form of a change of both energy peak position and count rate with irradiation time. Despite these operational issues the ability to detect fast neutrons and distinguish neutron energies was observed. This performance was demonstrated over a wide dynamic range (500–40,000 neutrons/s), with neutron induced polarisation being demonstrated in D-PC and SiC-SI at high fluxes.

  7. 8-group relative delayed neutron yields for epithermal neutron induced fission of 235U and 239Pu

    International Nuclear Information System (INIS)

    Piksaikin, V.M.; Kazakov, L.E.; Isaev, S.G.; Korolev, G.G.; Roshchenko, V.A.; Tertychnyj, R.G

    2002-01-01

    An 8-group representation of relative delayed neutron yields was obtained for epithermal neutron induced fission of 235 U and 239 Pu. These data were compared with ENDF/B-VI data in terms of the average half- life of the delayed neutron precursors and on the basis of the dependence of reactivity on the asymptotic period. (author)

  8. The neutronic design and performance of the Indiana University Cyclotron Facility (IUCF) Low Energy Neutron Source (LENS)

    Science.gov (United States)

    Lavelle, Christopher M.

    Neutron scattering research is performed primarily at large-scale facilities. However, history has shown that smaller scale neutron scattering facilities can play a useful role in education and innovation while performing valuable materials research. This dissertation details the design and experimental validation of the LENS TMR as an example for a small scale accelerator driven neutron source. LENS achieves competitive long wavelength neutron intensities by employing a novel long pulse mode of operation, where the neutron production target is irradiated on a time scale comparable to the emission time of neutrons from the system. Monte Carlo methods have been employed to develop a design for optimal production of long wavelength neutrons from the 9Be(p,n) reaction at proton energies ranging from 7 to 13 MeV proton energy. The neutron spectrum was experimentally measured using time of flight, where it is found that the impact of the long pulse mode on energy resolution can be eliminated at sub-eV neutron energies if the emission time distribution of neutron from the system is known. The emission time distribution from the TMR system is measured using a time focussed crystal analyzer. Emission time of the fundamental cold neutron mode is found to be consistent with Monte Carlo results. The measured thermal neutron spectrum from the water reflector is found to be in agreement with Monte Carlo predictions if the scattering kernels employed are well established. It was found that the scattering kernels currently employed for cryogenic methane are inadequate for accurate prediction of the cold neutron intensity from the system. The TMR and neutronic modeling have been well characterized and the source design is flexible, such that it is possible for LENS to serve as an effective test bed for future work in neutronic development. Suggestions for improvements to the design that would allow increased neutron flux into the instruments are provided.

  9. Chart of nuclides relating to neutron activation

    International Nuclear Information System (INIS)

    Okada, Minoru

    1981-09-01

    This chart is for frequent use in the prediction of the product species of neutron activation. The first edition of the chart has been made in 1976 after the repeated trial preparation. It has the following good points. (1) Any letter in chart is as large as one can read easily. [This condition has been obtained by the selection of items to be shown in chart. They are the name (the symbol of element, mass number, and half-life) of nuclide or of isomer, and the type of decay.]. (2) Decay product has been shown indirectly for branchings with two-step decay via short-lived daughter in an excited state. [This matter has been realized by use of the new mode of indication.] (3) Nuclides shown in chart are (a) naturally occurring nuclides and (b) nuclides formed from naturally occurring nuclides through one of the following reactions: (n, γ), (n, n'), (n, p), (n, α), (n, 2n), (n, pn), (n, 3n), (n, αn), (n, t), (n, 3 He), (n, 2p), and (n, γ)(n, γ). In the revision of the first edition, some modes of indication have become a little simpler, and the isomers of shorter half-lives (0.1 - 1 μs) have been added. (author)

  10. The minireactor Mirene for neutron-radiography: performances and applications

    International Nuclear Information System (INIS)

    Houelle, M.; Gerberon, J.M.

    1981-05-01

    The MIRENE neutron radiograhy mini-reactor is described. The core contains only one kilogram of enriched uranium in solution form. It works by pulsed operation. The neutron bursts produced are collimated into two beams which pass through the concrete protection around the reactor block. The performance of the reactor and the results achieved since it went into service in 1977 are described. These concern various fields. In the nuclear field: examination of fast neutron reactor fissile pins, monitoring of neutron absorbing screens employed to guarantee the safety-criticality of the transport and storage of the nuclear fuel cycle, observation of irradiated oxide fuel pellets in order to determine the fuel state equation of the fast neutron system, examination of UO 2 and water mixtures for criticality experiments. In the industrial field, Mirene has a vast field of application. Two examples are given: monitoring of electric insulation sealing, visualization of the bonding of two high density metal parts. Finally an original application in agronomy has given very good results: this concerns the on-site follow-up of the root growth of maize plants [fr

  11. The EUROBALL neutron wall - design and performance tests of neutron detectors

    CERN Document Server

    Skeppstedt, Ö; Lindström, L; Wadsworth, R; Hibbert, I; Kelsall, N; Jenkins, D; Grawe, H; aGórska, M; Moszynski, M; Sujkowski, Z; Wolski, D; Kapusta, M; Hellström, M; Kalogeropoulos, S; Oner, D; Johnson, A; Cederkäll, J; Klamra, W; Nyberg, J; Weiszflog, M; Kay, J; Griffiths, R; Garces-Narro, J; Pearson, C; Eberth, J

    1999-01-01

    The mechanical design of the EUROBALL neutron wall and neutron detectors, and their performance measured with a sup 2 sup 4 sup 6 sup , sup 2 sup 4 sup 8 Cm fission source are described. The array consists of 15 pseudohexaconical detector units subdivided into three, 149 mm high, hermetically separated segments and a smaller central pentagonal unit subdivided into five segments. The detectors are filled with Bicron BC501A liquid scintillator. Each section of the hexaconical detectors is viewed by a 130 mm diameter Philips XP4512PA photomultiplier while the sections of pentagonal detectors are viewed by Philips XP4312B PMTs. The tests of n-gamma discrimination performed by zero-crossing and time-of-flight methods show a full separation of gamma- and neutron events down to 50 keV recoil electron energy. These tests demonstrate the excellent timing properties of the detectors and an average time resolution of 1.56 ns. The factors determining the efficiency of neutron detectors are discussed. The total efficiency...

  12. LANSCE (Los Alamos Neutron Scattering Center) target system performance

    International Nuclear Information System (INIS)

    Russell, G.J.; Gilmore, J.S.; Robinson, H.; Legate, G.L.; Bridge, A.; Sanchez, R.J.; Brewton, R.J.; Woods, R.; Hughes, H.G. III

    1989-01-01

    The authors measured neutron beam fluxes at LANSCE using gold foil activation techniques. They did an extensive computer simulation of the as-built LANSCE Target/Moderator/Reflector/Shield geometry. They used this mockup in a Monte Carlo calculation to predict LANSCE neutronic performance for comparison with measured results. For neutron beam fluxes at 1 eV, the ratio of measured data to calculated varies from ∼0.6-0.9. The computed 1 eV neutron leakage at the moderator surface is 3.9 x 10 10 n/eV-sr-s-μA for LANSCE high-intensity water moderators. The corresponding values for the LANSCE high-resolution water moderator and the liquid hydrogen moderator are 3.3 and 2.9 x 10 10 , respectively. LANSCE predicted moderator intensities (per proton) for a tungsten target are essentially the same as ISIS predicted moderator intensities for a depleted uranium target. The calculated LANSCE steady state unperturbed thermal (E 13 n/cm 2 -s. The unique LANSCE split-target/flux-trap-moderator system is performing exceedingly well. The system has operated without a target or moderator change for over three years at nominal proton currents of 25 μA of 800-MeV protons. 17 refs., 8 figs., 3 tabs

  13. New spallation neutron sources, their performance and applications

    International Nuclear Information System (INIS)

    1985-01-01

    Pulsed spallation sources now operating in the world are at the KEK Laboratory in Japan (the KENS source), at Los Alamos National Laboratory (WNR) and at Argonne National Laboratory (IPNS), both the latter being in the US. The Intense Pulsed Neutron Source (IPNS) is currently the world's most intense source with a peak neutron flux of 4 x 10 14 n cm -2 s -1 at a repetition rate of 30 Hz, and globally producing approx. 1.5 x 10 15 n/sec. Present pulsed sources are still relatively weak compared to their potential. In 1985 the Rutherford Spallation Neutron Source will come on line, and eventually be approx. 30 more intense than the present IPNS. Later, in 1986 the WNR/PSR option at Los Alamos will make that facility of comparable intensity, while a subcritical fission booster at IPNS will keep IPNS competitive. These new sources will expand the applications of pulsed neutrons but are still based on accelerators built for other scientific purposes, usually nuclear or high-energy physics. Accelerator physicists are now designing machines expressly for spallation neutron research, and the proton currents attainable appear in the milliamps. (IPNS now runs at 0.5 GeV and 14 μA). Such design teams are at the KFA Laboratory Julich, Argonne National Laboratory and KEK. Characteristics, particularly the different time structure of the pulses, of these new sources will be discussed. Such machines will be expensive and require national, if not international, collaboration across a wide spectrum of scientific disciplines. The new opportunities for neutron research will, of course, be dramatic with these new sources

  14. Neutronic performance of a benchmark 1-MW LPSS

    International Nuclear Information System (INIS)

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

    1995-01-01

    We used split-target/flux-trap-moderator geometry in our 1-MW LPSS computational benchmark performance calculations because the simulation models were readily available. Also, this target/moderator arrangement is a proven LANSCE design and a good neutronic performer. The model has four moderator viewed surfaces, each with a 13x13 cm field-of-view. For our scoping neutronic-performance calculations, we attempted to get as much engineering realism into the target-system mockup as possible. In our present model, we account for target/reflector dilution by cooling; the D 2 O coolant fractions are adequate for 1 MW of 800-MeV protons (1.25 mA). We have incorporated a proton beam entry window and target canisters into the model, as well as (partial) moderator and vacuum canisters. The model does not account for target and moderator cooling lines and baffles, entire moderator canisters, and structural material in the reflector

  15. Extended I-Love relations for slowly rotating neutron stars

    Science.gov (United States)

    Gagnon-Bischoff, Jérémie; Green, Stephen R.; Landry, Philippe; Ortiz, Néstor

    2018-03-01

    Observations of gravitational waves from inspiralling neutron star binaries—such as GW170817—can be used to constrain the nuclear equation of state by placing bounds on stellar tidal deformability. For slowly rotating neutron stars, the response to a weak quadrupolar tidal field is characterized by four internal-structure-dependent constants called "Love numbers." The tidal Love numbers k2el and k2mag measure the tides raised by the gravitoelectric and gravitomagnetic components of the applied field, and the rotational-tidal Love numbers fo and ko measure those raised by couplings between the applied field and the neutron star spin. In this work, we compute these four Love numbers for perfect fluid neutron stars with realistic equations of state. We discover (nearly) equation-of-state independent relations between the rotational-tidal Love numbers and the moment of inertia, thereby extending the scope of I-Love-Q universality. We find that similar relations hold among the tidal and rotational-tidal Love numbers. These relations extend the applications of I-Love universality in gravitational-wave astronomy. As our findings differ from those reported in the literature, we derive general formulas for the rotational-tidal Love numbers in post-Newtonian theory and confirm numerically that they agree with our general-relativistic computations in the weak-field limit.

  16. Performance following a 500-675 rad neutron pulse

    International Nuclear Information System (INIS)

    Yochmowitz, M.G.; Brown, G.C.; Hardy, K.A.

    1985-01-01

    A three-light, three-lever discrete avoidance behavioral task was initiated to study the effects of a 500-675 rad neutron pulse upon performance. Eight primates performed the task for 4 h (3.5 h postexposure) on exposure day and for 4 h on each of 3 d postexposure. For the exposure day, five subjects had a decrease in correct responses, seven had increased reaction times, and six experienced productive emesis within 3.5 hours postexposure. Although the performance degradations were not severe, these data suggest that the performance of time critical tasks could be significantly impaired. 10 references

  17. Validation of SCALE code package on high performance neutron shields

    International Nuclear Information System (INIS)

    Bace, M.; Jecmenica, R.; Smuc, T.

    1999-01-01

    The shielding ability and other properties of new high performance neutron shielding materials from the KRAFTON series have been recently published. A comparison of the published experimental and MCNP results for the two materials of the KRAFTON series, with our own calculations has been done. Two control modules of the SCALE-4.4 code system have been used, one of them based on one dimensional radiation transport analysis (SAS1) and other based on the three dimensional Monte Carlo method (SAS3). The comparison of the calculated neutron dose equivalent rates shows a good agreement between experimental and calculated results for the KRAFTON-N2 material.. Our results indicate that the N2-M-N2 sandwich type is approximately 10% inferior as neutron shield to the KRAFTON-N2 material. All values of neutron dose equivalent obtained by SAS1 are approximately 25% lower in comparison with the SAS3 results, which indicates proportions of discrepancies introduced by one-dimensional geometry approximation.(author)

  18. Systematic study on the performance of elliptic focusing neutron guides

    International Nuclear Information System (INIS)

    Martin Rodriguez, D.; DiJulio, D.D.; Bentley, P.M.

    2016-01-01

    In neutron scattering experiments there is an increasing trend towards the study of smaller volume samples, which make the use of focusing optics more important. Focusing guide geometries based on conic-sections, such as those with parabolic and elliptic shapes, have been extensively used in both recently built neutron instruments and upgrades of existing hardware. A large fraction of proposed instruments at the European Spallation Source feature the requirement of good performance when measuring on small samples. The optimised design of a focusing system comes after time consuming Monte-Carlo (MC) simulations. Therefore, in order to help reduce the time needed to design such focusing systems, it is necessary to study systematically the performance of focusing guides. In the present work, we perform a theoretical analysis of the focusing properties of neutron beams, and validate them using a combination of Monte-Carlo simulations and Particle Swarm Optimisations (PSOs), where there is a close correspondence between the maximum divergence of the beam and the shape of the guide. The analytical results show that two limits can be considered, which bound a range of conic section shapes that provide optimum performance. Finally, we analyse a more realistic guide example and we give an assessment of the importance of the contribution from multiple reflections in different systems.

  19. Fast neutron irradiation deteriorates hippocampus-related memory ability in adult mice.

    Science.gov (United States)

    Yang, Miyoung; Kim, Hwanseong; Kim, Juhwan; Kim, Sung-Ho; Kim, Jong-Choon; Bae, Chun-Sik; Kim, Joong-Sun; Shin, Taekyun; Moon, Changjong

    2012-03-01

    Object recognition memory and contextual fear conditioning task performance in adult C57BL/6 mice exposed to cranial fast neutron irradiation (0.8 Gy) were examined to evaluate hippocampus-related behavioral dysfunction following acute exposure to relatively low doses of fast neutrons. In addition, hippocampal neurogenesis changes in adult murine brain after cranial irradiation were analyzed using the neurogenesis immunohistochemical markers Ki-67 and doublecortin (DCX). In the object recognition memory test and contextual fear conditioning, mice trained 1 and 7 days after irradiation displayed significant memory deficits compared to the sham-irradiated controls. The number of Ki-67- and DCX-positive cells decreased significantly 24 h post-irradiation. These results indicate that acute exposure of the adult mouse brain to a relatively low dose of fast neutrons interrupts hippocampal functions, including learning and memory, possibly by inhibiting neurogenesis.

  20. Performance of neutron and gamma personnel dosimetry in mixed radiation fields

    International Nuclear Information System (INIS)

    Swaja, R.E.; Sims, C.S.

    1981-01-01

    From 1974 to 1980, six personnel dosimetry intercomparison studies (PDIS) were conducted at the Oak Ridge National Laboratory (ORNL) to evaluate the performance of personnel dosimeters in a variety of neutron and gamma fields produced by operating the Health Physics Research Reactor (HPRR) in the steady state mode with and without spectral modifying shields. A total of 58 different organizations participated in these studies which produced approximately 2000 measurements of neutron and gamma dose equivalents on anthropomorphic phantoms for five different reactor spectra. Based on these data, the relative performance of three basic types of neutron dosimeters [nuclear emulsion film, thermoluminescent (TLD), and track-etch] and two basic types of gamma dosimeters (film and TLD) in mixed radiation fields was assessed

  1. Description and performance characteristics for the neutron Coincidence Collar for the verification of reactor fuel assemblies

    International Nuclear Information System (INIS)

    Menlove, H.O.

    1981-08-01

    An active neutron interrogation method has been developed for the measurement of 235 U content in fresh fuel assemblies. The neutron Coincidence Collar uses neutron interrogation with an AmLi neutron source and coincidence counting the induced fission reaction neutrons from the 235 U. This manual describes the system components, operation, and performance characteristics. Applications of the Coincidence Collar to PWR and BWR types of reactor fuel assemblies are described

  2. Performance of non-conventional factorization approaches for neutron kinetics

    International Nuclear Information System (INIS)

    Bulla, S.; Nervo, M.

    2013-01-01

    The use of factorization techniques provides a interesting option for the simulation of the time-dependent behavior of nuclear systems with a reduced computational effort. While point kinetics neglects all spatial and spectral effects, quasi-statics and multipoint kinetics allow to produce results with a higher accuracy for transients involving relevant modifications of the neutron distribution. However, in some conditions these methods can not work efficiently. In this paper, we discuss some possible alternative formulations for the factorization process for neutron kinetics, leading to mathematical models of reduced complications that can allow an accurate simulation of transients involving spatial and spectral effects. The performance of these innovative approaches are compared to standard techniques for some test cases, showing the benefits and shortcomings of the method proposed. (authors)

  3. Deriving Quantitative Crystallographic Information from the Wavelength-Resolved Neutron Transmission Analysis Performed in Imaging Mode

    Directory of Open Access Journals (Sweden)

    Hirotaka Sato

    2017-12-01

    Full Text Available Current status of Bragg-edge/dip neutron transmission analysis/imaging methods is presented. The method can visualize real-space distributions of bulk crystallographic information in a crystalline material over a large area (~10 cm with high spatial resolution (~100 μm. Furthermore, by using suitable spectrum analysis methods for wavelength-dependent neutron transmission data, quantitative visualization of the crystallographic information can be achieved. For example, crystallographic texture imaging, crystallite size imaging and crystalline phase imaging with texture/extinction corrections are carried out by the Rietveld-type (wide wavelength bandwidth profile fitting analysis code, RITS (Rietveld Imaging of Transmission Spectra. By using the single Bragg-edge analysis mode of RITS, evaluations of crystal lattice plane spacing (d-spacing relating to macro-strain and d-spacing distribution’s FWHM (full width at half maximum relating to micro-strain can be achieved. Macro-strain tomography is performed by a new conceptual CT (computed tomography image reconstruction algorithm, the tensor CT method. Crystalline grains and their orientations are visualized by a fast determination method of grain orientation for Bragg-dip neutron transmission spectrum. In this paper, these imaging examples with the spectrum analysis methods and the reliabilities evaluated by optical/electron microscope and X-ray/neutron diffraction, are presented. In addition, the status at compact accelerator driven pulsed neutron sources is also presented.

  4. Effect of blanket assembly shuffling on LMR neutronic performance

    International Nuclear Information System (INIS)

    Khalil, H.; Fujita, E.K.

    1987-01-01

    Neutronic analyses of advanced liquid-metal reactors (LMRs) have generally been performed with assemblies in different batches scatter-loaded but not shuffled among the core lattice positions between cycles. While this refueling approach minimizes refueling time, significant improvements in thermal performance are believed to be achievable by blanket assembly shuffling. These improvements, attributable to mitigation of the early-life overcooling of the blankets, include reductions in peak clad temperatures and in the temperature gradients responsible for thermal striping. Here the authors summarize results of a study performed to: (1) assess whether the anticipated gains in thermal performance can be realized without sacrificing core neutronic performance, particularly the burnup reactivity swing rho/sub bu/, which determines the rod ejection worth; (2) determine the effect of various blanket shuffling operations on reactor performance; and (3) determine whether shuffling strategies developed for an equilibrium (plutonium-fueled) core can be applied during the transition from an initial uranium-fueled core as is being considered in the US advanced LMR program

  5. Performance of the intense pulsed neutron source accelerator system

    International Nuclear Information System (INIS)

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

    1983-01-01

    The Intense Pulsed Neutron Source (IPNS) facility has now been operating in a routine way for outside users since November 1, 1981. From that date through December of 1982, the accelerator system was scheduled for neutron science for 4500 hours. During this time the accelerator achieved its short-term goals by delivering about 380,000,000 pulses of beam totaling over 6 x 10 20 protons. The changes in equipment and operating practices that evolved during this period of intense running are described. The intensity related instability threshold was increased by a factor of two and the accelerator beam current has been ion source limited. Plans to increase the accelerator intensity are also described. Initial operating results with a new H - ion source are discussed

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

    International Nuclear Information System (INIS)

    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 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 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 2 moderator at the 1-MW LPSS is equivalent to about 1/4th the calculated neutronic performance of the best liquid D 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

  7. Performing Neutron Cross-Section Measurements at RIA

    International Nuclear Information System (INIS)

    Ahle, L.E.

    2003-01-01

    The Rare Isotope Accelerator (RIA) is a proposed accelerator for the low energy nuclear physics community. Its goal is to understand the natural abundances of the elements heavier than iron, explore the nuclear force in systems far from stability, and study symmetry violation and fundamental physics in nuclei. To achieve these scientific goals, RIA promises to produce isotopes far from stability in sufficient quantities to allow experiments. It would also produce near stability isotopes at never before seen production rates, as much as 10 12 pps. Included in these isotopes are many that are important to stockpile stewardship, such as 87 Y, 146-50 Eu, and 231 Th. Given the expected production rates at RIA and a reasonably intense neutron source, one can expect to make ∼10 μg targets of nuclei with a half-life of ∼1 day. Thus, it will be possible at RIA to obtain experimental information on the neutron cross section for isotopes that have to date only been determined by theory. There are two methods to perform neutron cross-section measurements, prompt and delayed. The prompt method tries to measure each reaction as it happens. The exact technique employed will depend on the reaction of interest, (n,2n), (n,γ), (n,p), etc. The biggest challenge with this method is designing a detector system that can handle the gamma ray background from the target. The delayed method, which is the traditional radiochemistry method for determining the cross-section, irradiates the targets and then counts the reaction products after the fact. While this allows one to avoid the target background, the allowed fraction of target impurities is extremely low. This is especially true for the desired reaction product with the required impurity fraction on the order of 10 -9 . This is particularly problematic for (n,2n) and (n,γ) reactions, whose reaction production cannot be chemically separated from the target. In either case, the first step at RIA to doing these measurements is

  8. Stakeholder relations and financial performance

    NARCIS (Netherlands)

    Scholtens, B.; Zhou, Y.

    2008-01-01

    We analyze how shareholder performance can be associated with stakeholder relations. As such, we try to find out whether there is an association between financial performance and stakeholder relations with respect to different theoretical notions about the firm. Financial performance is

  9. The use of multi-energy-group neutron diffusion theory to numerically evaluate the relative utility of three dial-detector neutron porosity well logging tools

    International Nuclear Information System (INIS)

    Zalan, T.A.

    1988-01-01

    Multi-energy-group neutron diffusion theory is used to numerically evaluate the utility of two different dual-detector neutron porosity logging devices, a 14 MeV (accelerator) neutron source - epithermal neutron detector device and a 4 MeV neutron source - capture gamma-ray detector device, relative to the traditional 4 MeV neutron source - thermal neutron detector device. Fast and epithermal neutron diffusion parameters are calculated using Monte Carlo - derived neutron flux distributions. Thermal parameters are calculated from tabulated cross sections. An existing analytical method to describe the transport of gamma-rays through common earth materials is modified in order to accommodate the modeling of the 4 MeV neutron - capture gamma-ray device. The 14 MeV neutron - epithermal neutron device is found to be less sensitive to porosity than the 4 MeV neutron - capture gamma-ray device, which in turn is found to be less sensitive to porosity than the traditional 4 MeV neutron - thermal neutron device. Salinity effects are found to be comparable for the 4 MeV neutron - capture gamma-ray and 4 MeV neutron - thermal neutron devices. The 4 MeV neutron capture gamma-ray measurement is found to be deepest investigating

  10. Performance Test for Neutron Detector and Associated System using Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Seongwoo; Park, Sung Jae; Cho, Man Soon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Oh, Se Hyun [USERS, Daejeon (Korea, Republic of); Shin, Ho Cheol [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    SPND (Self-Powered Neutron Detector) has been developed to extend its lifespan. ENFMS (Ex-Core Flux Monitoring System) of pressurized water reactor has been also improved. After the development and improvement, their performance must be verified under the neutron irradiation environment. We used a research reactor for the performance verification of neutron detector and associated system because the research reactor can meet the neutron flux level of commercial nuclear reactor. In this paper, we report the performance verification method and result for the SPND and ENFMS using the research reactor. The performance tests for the SPND and ENFMS were conducted using UCI TRIGA reactor. The test environment of commercial reactor’s neutron flux level must be required. However, it is difficult to perform the test in the commercial rector due to the constraint of time and space. The research reactor can be good alternative neutron source for the test of neutron detectors and associated system.

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

    International Nuclear Information System (INIS)

    Pynn, R.

    1995-01-01

    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

  12. Study on calibration of neutron efficiency and relative photo-yield of plastic scintillator

    International Nuclear Information System (INIS)

    Peng Taiping; Zhang Chuanfei; Li Rurong; Zhang Jianhua; Luo Xiaobing; Xia Yijun; Yang Zhihua

    2002-01-01

    A method used for the calibration of neutron efficiency and the relative photo yield of plastic scintillator is studied. T(p, n) and D(d, n) reactions are used as neutron resources. The neutron efficiencies and the relative photo yields of plastic scintillators 1421 (40 mm in diameter and 5 mm in thickness) and determined in the neutron energy range of 0.655-5 MeV

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

    International Nuclear Information System (INIS)

    Pynn, R.

    1997-01-01

    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

  14. Neutronic calculations for JET. Performed with the FURNACE2 program. (Final report JET contract JEO/9004)

    International Nuclear Information System (INIS)

    Verschuur, K.A.

    1996-10-01

    Neutron-transport calculations with the FURNACE(2) program system, in support of the Neutron Diagnostic Group at JET, have been performed since 1980, i.e. since the construction phase of JET. FURNACE(2) is a ray-tracing/multiple-reflection transport program system for toroidal geometries, that orginally was developed for blanket neutronics studies and which then was improved and extended for application to the neutron-diagnostics at JET. (orig./WL)

  15. Measurements of periods, relative abundances and absolute yields of delayed neutrons from fast neutron induced fission of {sup 237}Np

    Energy Technology Data Exchange (ETDEWEB)

    Piksaikine, V. [Institute of Physics and Power Engineering, Obninsk (Russian Federation)

    1997-03-01

    The experimental method for measurements of the delayed neutron yields and period is presented. The preliminary results of the total yield, relative abundances and periods are shown comparing with the previously reported values. (J.P.N.)

  16. ISINN-5. 5. International seminar on interaction of neutrons with nuclei. Neutron spectroscopy, nuclear structure, related topics

    International Nuclear Information System (INIS)

    1997-01-01

    The materials submitted at the fifth in a series of annual international seminar on interaction of neutrons with nuclei Neutron Spectroscopy, Nuclear Structure, Related Topics (ISINN-5) are given. The Seminar is organized by the Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research and took place in Dubna on May 14-17, 1997. About 130 specialists from Belgium, China, Germany, France, Japan, Korea, Latvia, Netherlands, Ukraine, 7 Russian research institutes and a number of JINR laboratories took part in the Seminar. The scope of the problems discussed is traditionally wide. It includes the problems of violation of fundamental symmetries in the interaction of neutrons with nuclei, the properties of the neutron as the fundamental particle, nonstatistical aspects of the radiation capture of neutrons by nuclei, topical problems of the theory of nucleus, and the fission mechanism of heavy nuclei. The latest results obtained with ultracold neutrons (UCN), in particular, different approaches to understanding of the cause of UCN anomalous leakage through the walls of the trap are considered as well. The wide spectrum of methodological aspects of neutron-aided experiments is also discussed in details

  17. ''In situ'' electronic testing method of a neutron detector performance

    International Nuclear Information System (INIS)

    Gonzalez, J.M.; Levai, F.

    1987-01-01

    The method allows detection of any important change in the electrical characteristics of a neutron sensor channel. It checks the response signal produced by an electronic detector circuit when a pulse generator is connected as input signal in the high voltage supply. The electronic circuit compares the detector capacitance value, previously measured, against a reference value, which is adjusted in a window type comparator electronic circuit to detect any important degrading condition of the capacitance value in a detector-cable system. The ''in-situ'' electronic testing method of neutron detector performance has been verified in a laboratory atmosphere to be a potential method to detect any significant change in the capacitance value of a nuclear sensor and its connecting cable, also checking: detector disconnections, cable disconnections, length changes of the connecting cable, electric short-opened circuits in the sensor channel, and any electrical trouble in the detector-connector-cable system. The experimental practices were carried out by simulation of several electric changes in a nuclear sensor-cable system from a linear D.C. channel which measures reactor power during nuclear reactor operation. It was made at the Training Reactor Electronic Laboratory. The results and conclusions obtained at the Laboratory were proved, satisfactorily, in the Electronic Instrumentation of Budapest Technical University Training Reactor, Hungary

  18. Numerical relativity simulations of precessing binary neutron star mergers

    Science.gov (United States)

    Dietrich, Tim; Bernuzzi, Sebastiano; Brügmann, Bernd; Ujevic, Maximiliano; Tichy, Wolfgang

    2018-03-01

    We present the first set of numerical relativity simulations of binary neutron mergers that include spin precession effects and are evolved with multiple resolutions. Our simulations employ consistent initial data in general relativity with different spin configurations and dimensionless spin magnitudes ˜0.1 . They start at a gravitational-wave frequency of ˜392 Hz and cover more than 1 precession period and about 15 orbits up to merger. We discuss the spin precession dynamics by analyzing coordinate trajectories, quasilocal spin measurements, and energetics, by comparing spin aligned, antialigned, and irrotational configurations. Gravitational waveforms from different spin configuration are compared by calculating the mismatch between pairs of waveforms in the late inspiral. We find that precession effects are not distinguishable from nonprecessing configurations with aligned spins for approximately face-on binaries, while the latter are distinguishable from nonspinning configurations. Spin precession effects are instead clearly visible for approximately edge-on binaries. For the parameters considered here, precession does not significantly affect the characteristic postmerger gravitational-wave frequencies nor the mass ejection. Our results pave the way for the modeling of spin precession effects in the gravitational waveform from binary neutron star events.

  19. Improvements in or relating to neutron beam collimators

    International Nuclear Information System (INIS)

    Lundberg, D.A.

    1975-01-01

    Reference is made to collimators suitable for use in neutron therapy equipment. The design of such collimators presents considerable difficulties, since neutrons are very penetrating. Scattering processes are also much more significant with neutrons than with x-rays or γ-rays. A further difficulty is that neutron activation causes some materials to become radioactive, which may present a hazard to users of the equipment. A novel form of collimator is described that overcomes these disadvantages to some extent. It comprises a body containing W for moderating the neutrons by inelastic collision processes, a slow neutron absorbing material intimately mixed with the W for reducing collisions between slow neutrons and the W atoms, a hydrogenous material for further moderating the neutrons to thermal energies by elastic collision processes with H atoms and for absorbing the thermal neutrons by capture processes, and a material having a density of at least 10g/cm 3 for attenuating γ-radiation produced in the hydrogenous material during neutron capture processes. The collimator is of sufficient thickness to be substantially opaque to neutrons of predetermined energy. The slow neutron absorbing material may be B, the hydrogenous material may be polyethylene, and the high density material may be Pb. Alternative methods of using and packing the various materials are described. (U.K.)

  20. Neutronic performance of a 14 MW TRIGA reactor: LEU vs HEU fuel

    International Nuclear Information System (INIS)

    Bretscher, M.M.; Snelgrove, J.L.; Cornella, R.J.

    1983-01-01

    A primary objective of the US Reduced Enrichment Research and Test Reactor (RERTR) Program is to develop means for replacing, wherever possible, currently used highly-enriched uranium (HEU) fuel ( 235 U enrichment > 90%) with low-enriched uranium (LEU) fuel ( 235 U enrichment < 20%) without significantly degrading the performance of research and test reactors. The General Atomic Company has developed a low-enriched but high uranium content Er-U-ZrH/sub 1.6/ fuel to enable the conversion of TRIGA reactors (and others) from HEU to LEU. One possible application is to the water-moderated 14 MW TRIGA Steady State Reactor (SSR) at the Romanian Institute for Nuclear Power Reactors. The work reported here was undertaken for the purpose of comparing the neutronic performance of the SSR for HEU fuel with that for LEU fuel. In order to make these relative comparisons as valid as possible, identical methods and models were used for the neutronic calculations

  1. Development of temperature related thermal neutron scattering database for MCNP

    International Nuclear Information System (INIS)

    Mei Longwei; Cai Xiangzhou; Jiang Dazhen; Chen Jingen; Guo Wei

    2013-01-01

    Based on ENDF/B-Ⅶ neutron library, the thermal neutron scattering library S(α, β) for molten salt reactor moderators was developed. The temperatures of this library were chose as the characteristic temperature of the molten salt reactor. The cross section of the thermal neutron scattering of ACE format was investigated, and this library was also validated by the benchmarks of ICSBEP. The uncertainties shown in the validation were in reasonable range when compared with the thermal neutron scattering library tmccs which included in the MCNP data library. It was proved that the thermal neutron scattering library processed in this study could be used in the molten salt reactor design. (authors)

  2. Diagnosing implosion performance at the National Ignition Facility (NIF) by means of neutron spectrometry

    International Nuclear Information System (INIS)

    Frenje, J.A.; Casey, D.T.; Johnson, M. Gatu; Bionta, R.; Bond, E.J.; Caggiano, J.A.; Cerjan, C.; Edwards, J.; Eckart, M.; Fittinghoff, D.N.; Friedrich, S.; Glenzer, S.; Haan, S.; Hatarik, R.; Hatchett, S.; Jones, O.S.; Glebov, V.Yu.; Knauer, J.P.; Grim, G.; Kilkenny, J.D.

    2013-01-01

    The neutron spectrum from a cryogenically layered deuterium–tritium (dt) implosion at the National Ignition Facility (NIF) provides essential information about the implosion performance. From the measured primary-neutron spectrum (13–15 MeV), yield (Y n ) and hot-spot ion temperature (T i ) are determined. From the scattered neutron yield (10–12 MeV) relative to Y n , the down-scatter ratio, and the fuel areal density (ρR) are determined. These implosion parameters have been diagnosed to an unprecedented accuracy with a suite of neutron-time-of-flight spectrometers and a magnetic recoil spectrometer implemented in various locations around the NIF target chamber. This provides good implosion coverage and excellent measurement complementarity required for reliable measurements of Y n , T i and ρR, in addition to ρR asymmetries. The data indicate that the implosion performance, characterized by the experimental ignition threshold factor, has improved almost two orders of magnitude since the first shot taken in September 2010. ρR values greater than 1 g cm −2 are readily achieved. Three-dimensional semi-analytical modelling and numerical simulations of the neutron-spectrometry data, as well as other data for the hot spot and main fuel, indicate that a maximum hot-spot pressure of ∼150 Gbar has been obtained, which is almost a factor of two from the conditions required for ignition according to simulations. Observed Y n are also 3–10 times lower than predicted. The conjecture is that the observed pressure and Y n deficits are partly explained by substantial low-mode ρR asymmetries, which may cause inefficient conversion of shell kinetic energy to hot-spot thermal energy at stagnation. (paper)

  3. Computer-Related Task Performance

    DEFF Research Database (Denmark)

    Longstreet, Phil; Xiao, Xiao; Sarker, Saonee

    2016-01-01

    The existing information system (IS) literature has acknowledged computer self-efficacy (CSE) as an important factor contributing to enhancements in computer-related task performance. However, the empirical results of CSE on performance have not always been consistent, and increasing an individual......'s CSE is often a cumbersome process. Thus, we introduce the theoretical concept of self-prophecy (SP) and examine how this social influence strategy can be used to improve computer-related task performance. Two experiments are conducted to examine the influence of SP on task performance. Results show...... that SP and CSE interact to influence performance. Implications are then discussed in terms of organizations’ ability to increase performance....

  4. Dispersion relation for long-wave neutrons and the possibility of its precise experimental verification

    International Nuclear Information System (INIS)

    Frank, A.I.; Nosov, V.G.

    1995-01-01

    Modern theoretical concepts concerning the dispersion relation for slow neutrons in matter are considered. The generally accepted optical-potential model is apparently not quite accurate and should be supplemented with some small corrections in the energy range attainable in experiments. For ultracold neutrons, these corrections are related to the proximity of the applicability boundary of the theory; for cold neutrons, these corrections are due to correlations in the positions of scatters. The accuracy of existing experiments is insufficient for confirmation or refutation these conclusions. A precision experiment is proposed to verify the dispersion relation for long-wave neutrons. 30 refs., 3 figs

  5. Research on neutron radiography in Research Reactor Institute, Kyoto University and activities related to it

    International Nuclear Information System (INIS)

    Fujine, Shigenori; Yoneda, Kenji

    1994-01-01

    The research on neutron radiography in Research Reactor Institute, Kyoto University was begun in 1974 using the E-2 experimental hole which was designed for neutron irradiation. It was reconstructed for the excellent performance as neutron radiography facility by fixing aluminum plugs, a collimator and so on. The research activities thereafter are briefly described. In 1989, the cold neutron facility was installed in the graphite thermal neutron facility, and the experiment on cold neutron radiography became feasible. The reactor in Kyoto University is of the thermal output of 5 MW, and is put to the joint utilization by universities and research institutes in whole Japan. The experimental items carried out so far are enumerated. At present, the main subjects of research are the development of the standard for establishing image evaluation method, the analysis of gas-liquid two-phase flow, the construction of the data base for the literatures and images of neutron radiography, the application of cold neutron radiography, the development of the imaging method using fast neutrons and so on. The thermal neutron radiography and the cold neutron radiography facilities of Kyoto University research reactor are described. The research and activities at Kyoto University research reactor and the investigation of problems are reported. (K.I.) 56 refs

  6. Effect of Different Structural Materials on Neutronic Performance of a Hybrid Reactor

    Science.gov (United States)

    Übeyli, Mustafa; Tel, Eyyüp

    2003-06-01

    Selection of structural material for a fusion-fission (hybrid) reactor is very important by taking into account of neutronic performance of the blanket. Refractory metals and alloys have much higher operating temperatures and neutron wall load (NWL) capabilities than low activation materials (ferritic/martensitic steels, vanadium alloys and SiC/SiC composites) and austenitic stainless steels. In this study, effect of primary candidate refractory alloys, namely, W-5Re, T111, TZM and Nb-1Zr on neutronic performance of the hybrid reactor was investigated. Neutron transport calculations were conducted with the help of SCALE 4.3 System by solving the Boltzmann transport equation with code XSDRNPM. Among the investigated structural materials, tantalum had the worst performance due to the fact that it has higher neutron absorption cross section than others. And W-5Re and TZM having similar results showed the best performance.

  7. Neutron radiography of heated high-performance mortar

    Directory of Open Access Journals (Sweden)

    Weber B.

    2013-09-01

    Full Text Available Neutron radiography was applied to investigate the water distribution in mortar samples heated from one side to 600 °C. In mortar, aggregates and anhydrous cement are almost transparent to neutrons, while hydration products and water-filled capillary pores bear the largest attenuation. The evolution of the moisture profile shows a sharp dehydration front and accumulation of water due to condensation of water vapor behind this front.

  8. On the reciprocity-like relations in linear neutron transport theory

    International Nuclear Information System (INIS)

    Modak, R.S.; Sahni, D.C.

    1997-01-01

    The existence of certain reciprocity-like relations in neutron transport theory was shown earlier under some quite restrictive conditions. Here, these relations are shown to be valid in more general situations by using a different approach based on individual neutron trajectories. (author)

  9. Neutronic design and performance analysis of Korean ITER TBM by Monte Carlo method

    International Nuclear Information System (INIS)

    Kim, Chang Hyo; Han, Beom Seok; Park, Ho Jin

    2006-01-01

    The objective of this project is to develop a neutronic design of the Korean TBM(Test Blanket Module) which will be installed in ITER(International Thermonuclear Experimental Reactor). This project is intended to analyze a neutronic design and nuclear performances of the Korean ITER TBM through the transport calculation of MCCARD. In detail, we will conduct numerical experiments for developing the neutronic design of the Korean ITER TBM and improving the nuclear performances. The results of the numerical experiments produced in this project will be utilized for a design optimization of the Korean ITER TBM. In this project, we proposed the neutronic methodologies for analyzing the nuclear characteristics of the fusion blanket. In order to investigate the behavior of neutrons and photons in the fusion blanket, Monte Carlo transport calculation was conducted with MCCARD. In addition, to optimize the neutronic performances of the fusion blanket, we introduced the design concept using a graphite reflector and a Pb multiplier. Through various numerical experiments, it was verified that these design concepts can be utilized efficiently to improve neutronic performances and resolve many drawbacks. The graphite-reflected HCML blanket can provide the neutronic performances far better than the non-reflected blanket, and a slightly-enriched Li breeder can satisfy the tritium self-sufficiency. The HCSB blanket design concept with a graphite reflector and a Pb multiplier was proposed. According to results of the neutronic analyses, the graphite-reflected HCSB blanket with a Pb multiplier can provide the neutronic performances comparable with those of the conventional HCSB blanket

  10. Phonon dispersion relation in zircon, ZrSiO4 using inelastic neutron scattering at a pulsed neutron source

    International Nuclear Information System (INIS)

    Mittal, R.; Chaplot, S.L.; Parthasarathy, R.; Bull, M.J.; Harris, M.J.

    2000-01-01

    The coherent inelastic neutron scattering technique is used for the measurements of phonon dispersion relation in a geophysically important mineral zircon using PRISMA spectrometer as ISIS, UK. Lattice dynamical calculations of the phonon dispersion relation are carried out using a shell model. The one-phonon structure factors are calculated for selecting the Bragg points for the measurements and assignment of phonons to different branches. The calculations are in good agreement with the measured phonon dispersion relation. (author)

  11. Optimising neutron polarizers--measuring the flipping ratio and related quantities

    CERN Document Server

    Goossens, D J

    2002-01-01

    The continuing development of gaseous spin polarized sup 3 He transmission filters for use as neutron polarizers makes the choice of optimum thickness for these filters an important consideration. The 'quality factors' derived for the optimisation of transmission filters for particular measurements are general to all neutron polarizers. In this work optimisation conditions for neutron polarizers are derived and discussed for the family of studies related to measuring the flipping ratio from samples. The application of the optimisation conditions to sup 3 He transmission filters and other types of neutron polarizers is discussed. Absolute comparisons are made between the effectiveness of different types of polarizers for this sort of work.

  12. Neutronic performance optimization study of Indian fusion demo reactor first wall and breeding blanket

    International Nuclear Information System (INIS)

    Swami, H.L.; Danani, C.

    2015-01-01

    In frame of design studies of Indian Nuclear Fusion DEMO Reactor, neutronic performance optimization of first wall and breeding blanket are carried out. The study mainly focuses on tritium breeding ratio (TBR) and power density responses estimation of breeding blanket. Apart from neutronic efficiency of existing breeding blanket concepts for Indian DEMO i.e. lead lithium ceramic breeder and helium cooled solid breeder concept other concepts like helium cooled lead lithium and helium-cooled Li_8PbO_6 with reflector are also explored. The aim of study is to establish a neutronically efficient breeding blanket concept for DEMO. Effect of first wall materials and thickness on breeding blanket neutronic performance is also evaluated. For this study 1 D cylindrical neutronic model of DEMO has been constructed according to the preliminary radial build up of Indian DEMO. The assessment is being done using Monte Carlo based radiation transport code and nuclear cross section data file ENDF/B- VII. (author)

  13. Developments of high-performance moderator vessel for JRR-3 cold neutron source

    International Nuclear Information System (INIS)

    Arai, Masaji; Tamura, Itaru; Hazawa, Tomoya

    2015-05-01

    The cold neutron source (CNS) facility converts thermal neutrons into cold neutrons to moderate neutrons with liquid hydrogen. The cold neutron beam at Japan Research Reactor No. 3 (JRR-3) is led to the beam experimental devices in the beam hall through neutron guide tubes. High intensities of the cold neutron beam are always demanded for increasing the experimental effectiveness and accuracy. In the Department of Research Reactor and Tandem Accelerator, developments of high-performance CNS moderator vessel that can produce cold neutron intensity about two times higher compared to the existing vessel have been performed in the second medium term plans. We compiled this report about the technological development to solve several problems with the design and manufacture of new vessel. In the present study, design strength evaluation, mockup test, simulation for thermo-fluid dynamics of the liquid hydrogen and strength evaluation of the different-material-bonding were studied. By these evaluation results, we verified that the developed new vessel can be applied to CNS moderator vessel of JRR-3. (author)

  14. Using FLUKA to Study Concrete Square Shield Performance in Attenuation of Neutron Radiation Produced by APF Plasma Focus Neutron Source

    Science.gov (United States)

    Nemati, M. J.; Habibi, M.; Amrollahi, R.

    2013-04-01

    In 2010, representatives from the Nuclear Engineering and physics Department of Amirkabir University of Technology (AUT) requested development of a project with the objective of determining the performance of a concrete shield for their Plasma Focus as neutron source. The project team in Laboratory of Nuclear Engineering and physics department of Amirkabir University of Technology choose some shape of shield to study on their performance with Monte Carlo code. In the present work, the capability of Monte Carlo code FLUKA will be explored to model the APF Plasma Focus, and investigating the neutron fluence on the square concrete shield in each region of problem. The physical models embedded in FLUKA are mentioned, as well as examples of benchmarking against future experimental data. As a result of this study suitable thickness of concrete for shielding APF will be considered.

  15. Performance Study of an aSi Flat Panel Detector for Fast Neutron Imaging of Nuclear Waste

    Energy Technology Data Exchange (ETDEWEB)

    Schumann, M.; Mauerhofer, E. [Institute of Energy and Climate Research - Nuclear Waste Management and Reactor Safety, Forschungszentrum Juelich GmbH, 52425 Juelich (Germany); Engels, R.; Kemmerling, G. [Central Institute for Engineering, Electronics and Analytics - Electronic Systems, Forschungszentrum Juelich GmbH, 52425 Juelich (Germany); Frank, M. [MATHCCES - Department of Mathematics, RWTH Aachen University, 52062 Aachen (Germany); Havenith, A.; Kettler, J.; Klapdor-Kleingrothaus, T. [Institute of Nuclear Engineering and Technology Transfer, RWTH Aachen University, 52062 Aachen (Germany); Schitthelm, O. [Corporate Technology, Siemens AG, 91058 Erlangen (Germany)

    2015-07-01

    }Am) were performed. A homemade algorithm was developed to determine a value which is related to the neutron absorption of the sample with the analysis of the raw detector data. The detector was placed 42 cm away from the neutron source. Distance between detector and the samples was 0.5 cm. At the sample position the fast neutron flux was estimated to 9x10{sup 3} n cm{sup -2} s{sup -1} for a neutron emission of 10{sup 8} n s{sup -1}. The acquisition time was 15 minutes. First neutron radiographs were successfully recorded despite the low detector efficiency and low neutron emission. Analysis of the data shows a correlation between the measured signal and determined neutron absorption. Thus discrimination between different materials of same thicknesses may be achieved. The measurements and results will be presented and discussed in details.

  16. Neutron irradiation effects in fusion or spallation structural materials: Some recent insights related to neutron spectra

    International Nuclear Information System (INIS)

    Garner, F.A.; Greenwood, L.R.

    1998-01-01

    A review is presented of recent insights on the role of transmutation in the development of radiation-induced changes in dimension or radiation-induced changes in physical or mechanical properties. It is shown that, in some materials and some neutron spectra, transmutation can significantly affect or even dominate a given property change process. When the process under study is also sensitive to displacement rate, and especially if it involves radiation-induced segregation and precipitation, it becomes much more difficult to separate the transmutation and displacement rate dependencies. This complicates the application of data derived from 'surrogate' spectra to predictions in other flux-spectra environments. It is also shown in this paper that one must be sensitive to the impact of previously -ignored 'small' variations in neutron spectra within a given reactor. In some materials these small variations have major consequences. (author)

  17. Recent performance of the Intense Pulsed Neutron Source accelerator system

    International Nuclear Information System (INIS)

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

    1987-03-01

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

  18. Performance of novel moderator for pulsed neutron diffraction

    International Nuclear Information System (INIS)

    Mayer, R.E.; Granada, J.R.; Dawidowski, J.; Gillette, V.H.

    1991-01-01

    Measurements of neutron pulse time-width and intensity have been carried out on grids of small moderators placed side by side and decoupled by cadmium strips. This moderator concept had been introduced at ICANS-10. The present measurements explore greater moderator thicknesses than those previously attained, yielding information on thickness optimization, while confirming the previous results on resolution which make this moderator a favourable choice in front of the conventional sandwich set-up. (author)

  19. Neutronic performance of Indian LLCB TBM set conceptual design in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Swami, H.L., E-mail: hswami@ipr.res.in; Shaw, A.K.; Mistry, A.N.; Danani, C.

    2016-12-15

    Highlights: • Neutronic analyses of conceptual design of LLCB test blanket module in ITER have been performed. • The estimated total tritium production rate in the LLCB TBM is 1.66E + 17 tritons/s. • Total heat deposited in the LLCB TBM is 0.46 MW and highest power density at TBM first wall is 5.2 Watt/cc. • The estimation shows the maximum DPA 2.72 at TBM FW. - Abstract: Tritium breeding blanket testing program in ITER is an important milestone towards the development of the fusion reactors. ITER organization is providing an opportunity to the partner countries to test their breeding blanket concepts. A mock-up of Indian Lead Lithium Ceramic Breeder (LLCB) tritium breeding blanket known as LLCB Test Blanket Module (TBM) will be tested in ITER equatorial port no. 2. LLCB blanket consists of lead lithium (PbLi) as a neutron multiplier & tritium breeder, ceramic breeder (Li{sub 2}TiO{sub 3}) as a tritium breeder and India specific Reduced Activation Ferretic Martinic Steel (IN-RAFMS) as a structural material. A stainless steel block which is cooled by water, called as shield block, is attached with TBM to provide neutron shield to ITER TBM port. A comprehensive neutronic performance evaluation is required for the design of the LLCB TBM set (TBM + shield block) and associated ancillary systems in ITER. The neutronic performance of the conceptual design of TBM set in ITER has been carried out and reported here. In order to carry out the neutronic performance evaluation, the neutronic models of the LLCB TBM set along with TBM frame have been constructed and inserted in the equatorial port of ITER reference neutronic model C-lite. Neutronic responses such as tritium production rate, nuclear heating, neutron flux & spectra, gas production & DPA in the LLCB TBM set are calculated considering 500 MW fusion power & fluence level of 0.3 MWa/m{sup 2}. Radiation transport code MCNP6 and FENDL 2.1 nuclear cross-section data library are used to perform the neutronic

  20. Stability of the Hall sensors performance under neutron irradiation

    International Nuclear Information System (INIS)

    Duran, I.; Hron, M.; Stockel, J.; Viererbl, L.; Vsolak, R.; Cerva, V.; Bolshakova, I.; Holyaka, R.; Vayakis, G.

    2004-01-01

    A principally new diagnostic method must be developed for magnetic measurements in steady state regime of operation of fusion reactor. One of the options is the use of transducers based on Hall effect. The use of Hall sensors in ITER is presently limited by their questionable radiation and thermal stability. Issues of reliable operation in ITER like radiation and thermal environment are addressed in the paper. The results of irradiation tests of candidate Hall sensors in LVR-15 and IBR-2 experimental fission reactors are presented. Stable operation (deterioration of sensitivity below one percent) of the specially prepared sensors was demonstrated during irradiation by the total fluence of 3.10 16 n/cm 2 in IBR-2 reactor. Increasing the total neutron fluence up to 3.10 17 n/cm 2 resulted in deterioration of the best sensor's output still below 10% as demonstrated during irradiation in LVR-15 fission reactor. This level of neutron is already higher than the expected ITER life time neutron fluence for a sensor location just outside the ITER vessel. (authors)

  1. Neutron activation analysis of archaeological artifacts using the conventional relative method: a realistic approach for analysis of large samples

    International Nuclear Information System (INIS)

    Bedregal, P.S.; Mendoza, A.; Montoya, E.H.; Cohen, I.M.; Universidad Tecnologica Nacional, Buenos Aires; Oscar Baltuano

    2012-01-01

    A new approach for analysis of entire potsherds of archaeological interest by INAA, using the conventional relative method, is described. The analytical method proposed involves, primarily, the preparation of replicates of the original archaeological pottery, with well known chemical composition (standard), destined to be irradiated simultaneously, in a well thermalized external neutron beam of the RP-10 reactor, with the original object (sample). The basic advantage of this proposal is to avoid the need of performing complicated effect corrections when dealing with large samples, due to neutron self shielding, neutron self-thermalization and gamma ray attenuation. In addition, and in contrast with the other methods, the main advantages are the possibility of evaluating the uncertainty of the results and, fundamentally, validating the overall methodology. (author)

  2. Special and general relativity with applications to white dwarfs, neutron stars and black holes

    CERN Document Server

    Glendenning, Norman K

    2007-01-01

    Special and General Relativity are concisely developed together with essential aspects of nuclear and particle physics. Problem sets are provided for many chapters, making the book ideal for a course on the physics of white dwarf and neutron star interiors.

  3. Flux gain for a next-generation neutron reflectometer resulting from improved supermirror performance

    CERN Document Server

    Rehm, C

    2002-01-01

    Next-generation spallation neutron source facilities will offer instruments with unprecedented capabilities through simultaneous enhancement of source power and usage of advanced optical components. The Spallation Neutron Source (SNS), already under construction at Oak Ridge National Laboratory and scheduled to be completed by 2006, will provide greater than an order of magnitude more effective source flux than current state-of-the-art facilities, including the most advanced research reactors. An additional order of magnitude gain is expected through the use of new optical devices and instrumentation concepts. Many instrument designs require supermirror neutron guides with very high critical angles for total reflection. In this contribution, we will discuss how the performance of a modern neutron-scattering instrument depends on the efficiency of these supermirrors. We summarize current limitations of supermirror coatings and outline ideas for enhancing their performance, particularly for improving the reflec...

  4. Neutron scatter studies of chromatin structures related to functions

    International Nuclear Information System (INIS)

    Bradbury, E.M.

    1992-01-01

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

  5. Research performed at the ET-RR-1 reactor using the neutron scattering equipment

    International Nuclear Information System (INIS)

    Adib, M.; Maayouf, R.M.A.; Abdel-Kawy, A.

    1990-02-01

    This report represents the results of studies and measurements, performed at the ET-RR-1 reactor, using the neutron scattering equipment supplied by the IAEA according to the technical assistance project EGY/1/11/10. The results of these studies, starting in 1980 and continuing to date, are discussed; the use of the equipment, both as a neutron monochromator and fixed scattering angle spectrometer, is also assessed. (author). 19 refs, 17 figs

  6. The performance of an amorphous silicon flat panel for neutron imaging at the PSI NEUTRA facility

    International Nuclear Information System (INIS)

    Estermann, Mirko; Frei, Gabriel; Lehmann, Eberhard; Vontobel, Peter

    2005-01-01

    Commonly applied imaging methods in neutron radiography use a CCD camera in conjunction with a scintillator or imaging plates. CCDs and imaging plates have desirable properties concerning resolution, linearity, dynamic range and signal-to-noise ratio (S/N) but both techniques have the disadvantage of a slow read out and for the CCD camera, an additional disadvantage is the loss of light through the optical system. Amorphous silicon detectors, originally developed for medical and industrial X-ray imaging, generally do not have the above-mentioned disadvantages. These detectors have a much faster readout and, in comparison to the generally used crystalline silicon, can be put directly in the X-ray or neutron beam without being damaged. This type of detector also does not require any optical interface, minimizing possible light loss. The detector is operated at room temperature, which has some influence on the noise. Using the whole dynamic range with a low gain, results in a S/N of up to 30, for normal applications, however, a S/N of about 15-20 is typical. The main drawback of this imaging device is the dynamic range of only 12 bits and the relatively complicated operating system in which different operation modes can be chosen. In 2003, successful experiments were performed with this new device, but it is still in its fledgling stages and improvements from the manufacturer as well as the experience from the NEUTRA team will help to advance this technique for neutron imaging in a most efficient way

  7. Study of Phonon Dispersion Relations in Cuprous Oxide by Inelastic Neutron Scattering

    DEFF Research Database (Denmark)

    Beg, M. M.; Shapiro, S. M.

    1976-01-01

    Phonon dispersion relations in Cu2O have been studied at 20°C using inelastic neutron scattering. Seven acoustic branches and twelve optical branches have been studied in detail in the three symmetry directions [00ζ], [ζζ0], and [ζζζ] of the cubic lattice. Four of the six zone-center phonons have...... been observed and the assignments and energies are confirmed as Γ25=87±2 cm-1, Γ12′=105±3 cm-1, Γ15=146±1 cm-1, and Γ2′≈347 cm-1. The dispersion relations agree only qualitatively with the rigid-ion-model calculations. It is suggested that more detailed calculations may be performed in the light...

  8. Scintillating-Glass-Fiber neutron sensors, their application and performance for plutonium detection and monitoring

    International Nuclear Information System (INIS)

    Seymour, R.S.; Richardson, B.; Morichi, M.; Bliss, M.; Craig, R.A.; Sunberg, D.S.

    1998-01-01

    Most neutron detection sensors presently employ 3 He gas-filled detectors. Despite their excellent performance and widespread use, there are significant limitations to this technology. A significant alternative neutron sensor utilizing neutron-active material incorporated into a glass scintillator is presented that offers novel commercial sensors not possible or practical with gas tube technology. The scintillating optical fiber permits sensors with a multitude of sizes ranging from devices of a single fiber of 150μm to sensors with tens of thousands of fibers with areas as large as 5m 2 depending on the neutron flux to be measured. A second significant advantage is the use of high-speed electronics that allow a greater dynamic range, not possible with gas detectors. These sensors are flexible, conformable and less sensitive to vibration that optimizes the source-to-detector geometry and provides robust performance in field applications. The glass-fibers are sensitive to both gamma rays and neutrons. However the coincidence electronics are optimized for neutron to gamma ray discrimination allowing very sensitive measurements with a low false-alarm rate. Applications include SNM surveillance, material control and accountability (MC and A), safeguard inspections, Pu health physics / bioassay and environmental characterization. (author)

  9. Performance assessment of self-interrogation neutron resonance densitometry for spent nuclear fuel assay

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jianwei, E-mail: huj1@ornl.gov [Reactor and Nuclear Systems Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, PO Box 2008, MS-6172, Oak Ridge, TN 37831-6172 (United States); Tobin, Stephen J.; LaFleur, Adrienne M.; Menlove, Howard O.; Swinhoe, Martyn T. [Nuclear Engineering and Nonproliferation Division, Los Alamos National Laboratory (United States)

    2013-11-21

    Self-Interrogation Neutron Resonance Densitometry (SINRD) is one of several nondestructive assay (NDA) techniques being integrated into systems to measure spent fuel as part of the Next Generation Safeguards Initiative (NGSI) Spent Fuel Project. The NGSI Spent Fuel Project is sponsored by the US Department of Energy's National Nuclear Security Administration to measure plutonium in, and detect diversion of fuel pins from, spent nuclear fuel assemblies. SINRD shows promising capability in determining the {sup 239}Pu and {sup 235}U content in spent fuel. SINRD is a relatively low-cost and lightweight instrument, and it is easy to implement in the field. The technique makes use of the passive neutron source existing in a spent fuel assembly, and it uses ratios between the count rates collected in fission chambers that are covered with different absorbing materials. These ratios are correlated to key attributes of the spent fuel assembly, such as the total mass of {sup 239}Pu and {sup 235}U. Using count rate ratios instead of absolute count rates makes SINRD less vulnerable to systematic uncertainties. Building upon the previous research, this work focuses on the underlying physics of the SINRD technique: quantifying the individual impacts on the count rate ratios of a few important nuclides using the perturbation method; examining new correlations between count rate ratio and mass quantities based on the results of the perturbation study; quantifying the impacts on the energy windows of the filtering materials that cover the fission chambers by tallying the neutron spectra before and after the neutrons go through the filters; and identifying the most important nuclides that cause cooling-time variations in the count rate ratios. The results of these studies show that {sup 235}U content has a major impact on the SINRD signal in addition to the {sup 239}Pu content. Plutonium-241 and {sup 241}Am are the two main nuclides responsible for the variation in the count

  10. Initial performance of the Cornell cold neutron beam

    International Nuclear Information System (INIS)

    Clark, D.D.; Spern, S.A.; Atwood, A.G.

    1997-01-01

    The cold source for a guided neutron beam has been installed in a Cornell TRIGA beamport and has successfully undergone thermal tests up to full power (normally 480 kW). Tests to date (8/1/96) include spectral and yield measurements at 10 kW with the first three meters of the 2-cm by 5-cm Ni-on-glass guide in place. A 110-cm 3 Al chamber, located 17 cm from the core, contains solid mesitylene and is cooled by conduction through a 269-cm long Cu rod connected to a cryorefrigerator outside the reactor shield. Distributions of flux per unit velocity have been measured at 10 kW by time-of-flight. Anticipated properties of the complete 13 m long beam at full power are discussed. (author)

  11. Gravitational waves from axisymmetric rotating stellar core collapse to a neutron star in full general relativity

    International Nuclear Information System (INIS)

    Shibata, Masaru; Sekiguchi, Yu-ichirou

    2004-01-01

    Axisymmetric numerical simulations of rotating stellar core collapse to a neutron star are performed in the framework of full general relativity. The so-called Cartoon method, in which the Einstein field equations are solved in Cartesian coordinates and the axisymmetric condition is imposed around the y=0 plane, is adopted. The hydrodynamic equations are solved in cylindrical coordinates (on the y=0 plane in Cartesian coordinates) using a high-resolution shock-capturing scheme with maximum grid size (2500,2500). A parametric equation of state is adopted to model collapsing stellar cores and neutron stars following Dimmelmeier, Font, and Mueller. It is found that the evolution of the central density during the collapse, bounce, and formation of protoneutron stars agrees well with that in the work of Dimmelmeier, Font, and Mueller in which an approximate general relativistic formulation is adopted. This indicates that such an approximation is appropriate for following axisymmetric stellar core collapses and the subsequent formation of protoneutron stars. Gravitational waves are computed using a quadrupole formula. It is found that the waveforms are qualitatively in good agreement with those by Dimmelmeier, Font, and Mueller. However, quantitatively, two waveforms do not agree well. The possible reasons for the disagreement are discussed

  12. [Neutron scatter studies of chromatin structure related to function

    International Nuclear Information System (INIS)

    Bradbury, E.M.

    1990-01-01

    This study is concerned with the application of neutron scatter techniques to the different structural states of nucleosomes and chromatin with the long term objective of understanding how the enormous lengths of DNA are folded into chromosomes. Micrococcal nuclease digestion kinetics have defined two subnucleosome particles; the chromatosome with 168 bp DNA, the histone octamer and one H1 and the nucleosome core particle with 146 bp DNA and the histone octamer. As will be discussed, the structure of the 146 bp DNA core particle is known in solution at low resolution from neutron scatter studies and in crystals. Based on this structure, the authors have a working model for the chromatosome and the mode of binding of H1. In order to define the structure of the nucleosome and also the different orders of chromatin structures they need to know the paths of DNA that link nucleosomes and the factors associated with chromosome functions that act on those DNA paths. The major region for this situation is the inherent variabilities in nucleosome DNA sequences, in the histone subtypes and their states of chemical modification and in the precise locations of nucleosomes. Such variabilities obscure the underlying principles that govern the packaging of DNA into the different structural states of nucleosomes and chromatin. The only way to elucidate these principles is to study the structures of nucleosomes and oligonucleosomes that are fully defined. They have largely achieved these objectives

  13. Engineering related neutron diffraction measurements probing strains, texture and microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Clausen, Bjorn [Los Alamos National Laboratory; Brown, Donald W [Los Alamos National Laboratory; Tome, Carlos N [Los Alamos National Laboratory; Balogh, Levente [Los Alamos National Laboratory; Vogel, Sven C [Los Alamos National Laboratory

    2010-01-01

    Neutron diffraction has been used for engineering applications for nearly three decades. The basis of the technique is powder diffraction following Bragg's Law. From the measured diffraction patterns information about internal, or residual, strain can be deduced from the peak positions, texture information can be extracted from the peak intensities, and finally the peak widths can provide information about the microstructure, e.g. dislocation densities and grain sizes. The strains are measured directly from changes in lattice parameters, however, in many cases it is non-trivial to determine macroscopic values of stress or strain from the measured data. The effects of intergranular strains must be considered, and combining the neutron diffraction measurements with polycrystal deformation modeling has proven invaluable in determining the overall stress and strain values of interest in designing and dimensioning engineering components. Furthelmore, the combined use of measurements and modeling has provided a tool for elucidating basic material properties, such as critical resolved shear stresses for the active deformation modes and their evolution as a function of applied deformation.

  14. {sup 252}Cf spontaneous prompt fission neutron spectrum measured at 0 degree and 180 degree relative to the fragment motion

    Energy Technology Data Exchange (ETDEWEB)

    Shanglian, Bao; Jinquan, Liu [Beijing Univ., BJ (China); Batenkov, O I; Blinov, M V; Smirnov, S N [V.G. Khlopin Radium Institute, ST. Petersburg (Russian Federation)

    1994-09-01

    The {sup 252}Cf spontaneous prompt fission neutron spectrum at 0 degree and 180 degree relative to the motion direction of corresponding fission fragments was measured. High angular resolution for fragment measurements and high energy resolution for neutron measurements were obtained using multi-parameter TOF spectrometer. The results showed that there is a symmetric distribution of `forward` and `backward` for low energy in C.M.S. neutrons, which was an evidence of nonequilibrium neutrons existed in fission process.

  15. Measurements of Relative Biological Effectiveness and Oxygen Enhancement Ratio of Fast Neutrons of Different Energies

    Energy Technology Data Exchange (ETDEWEB)

    Barendsen, G. W.; Broerse, J. J. [Radiobiological Institute of the Health Research Council TNO, Rijswijk (ZH) (Netherlands)

    1968-03-15

    Impairment of the reproductive capacity of cultured cells of human kidney origin (T-l{sub g} cells) has been measured by the Puck cloning technique. From the dose-survival curves obtained in these experiments by irradiation of cells in equilibrium with air and nitrogen, respectively, the relative biological effectiveness (RBE) and the oxygen enhancement ratios (OER) were determined for different beams of fast neutrons. Monoenergetic neutrons of 3 and 15 MeV energy, fission spectrum fast neutrons (mean energy about 1.5 MeV), neutrons produced by bombarding Be with cyclotron-accelerated 16 MeV deuterons (mean energy about 6 MeV) and neutrons produced by bombarding Be with cyclotron- accelerated 20 MeV {sup 3}He ions (mean energy about 10 MeV) have been compared with 250 kVp X-rays as a standard reference. The RBE for 50% cell survival varies from 4.7 for fission-spectrum fast neutrons to 2.7 for 15 MeV monoenergetic neutrons. The OER is not strongly dependent on the neutron energy for the various beams investigated. For the neutrons with the highest and lowest energies used OER values of 1.6 {+-} 0.2 and 1.5 {+-} 0.1 were measured. An interpretation of these data on the basis of the shapes of the LET spectra is proposed and an approximate verification of this hypothesis is provided from measurements in which secondary particle equilibrium was either provided for or deliberately eliminated. (author)

  16. Performance of self-powered neutron detectors in pressurized water reactors

    International Nuclear Information System (INIS)

    Warren, H.D.; Bozarch, D.P.

    1977-01-01

    A typical Babcock and Wilcox pressurized water reactor (PWR) contains 364 rhodium self-powered neutron detectors (SPNDs) and 52 background detectors. The detectors are inserted into the reactor core in 52 dry, multidetector assemblies. Each assembly contains seven SPNDs and one background detector. By mid-1977, eight B and W PWRs, each fitted with SPNDs, were in operation. Many of the SPNDs have operated successfully for more than four years. This paper describes the operational performance of the SPNDs and special tests conducted to improve that performance. Topics included are (1) insulation performance versus neutron dose to the SPND, (2) background signals in the leadwire region of the SPND, and (3) depletion of the SPND emitter versus absorbed neutron dose

  17. Gravitational wave content and stability of uniformly, rotating, triaxial neutron stars in general relativity.

    Science.gov (United States)

    Tsokaros, Antonios; Ruiz, Milton; Paschalidis, Vasileios; Shapiro, Stuart L; Baiotti, Luca; Uryū, Kōji

    2017-06-15

    Targets for ground-based gravitational wave interferometers include continuous, quasiperiodic sources of gravitational radiation, such as isolated, spinning neutron stars. In this work, we perform evolution simulations of uniformly rotating, triaxially deformed stars, the compressible analogs in general relativity of incompressible, Newtonian Jacobi ellipsoids. We investigate their stability and gravitational wave emission. We employ five models, both normal and supramassive, and track their evolution with different grid setups and resolutions, as well as with two different evolution codes. We find that all models are dynamically stable and produce a strain that is approximately one-tenth the average value of a merging binary system. We track their secular evolution and find that all our stars evolve toward axisymmetry, maintaining their uniform rotation, rotational kinetic energy, and angular momentum profiles while losing their triaxiality.

  18. Neutron radiography

    International Nuclear Information System (INIS)

    Alaa eldin, M.T.

    2011-01-01

    The digital processing of the neutron radiography images gives the possibility for data quantification. In this case an exact relation between the measured neutron attenuation and the real macroscopic attenuation coefficient for every point of the sample is required. The assumption that the attenuation of the neutron beam through the sample is exponential is valid only in an ideal case where a monochromatic beam, non scattering sample and non background contribution are assumed. In the real case these conditions are not fulfilled and in dependence on the sample material we have more or less deviation from the exponential attenuation law. Because of the high scattering cross-sections of hydrogen (σs=80.26 barn) for thermal neutrons, the problem with the scattered neutrons at quantitative radiography investigations of hydrogenous materials (as PE, Oil, H 2 O, etc) is not trivial. For these strong scattering materials the neutron beam attenuation is no longer exponential and a dependence of the macroscopic attenuation coefficient on the material thickness and on the distance between the sample and the detector appears. When quantitative radiography (2 D) or tomography investigations (3 D) are performed, some image correction procedures for a description of the scattering effect are required. This thesis presents a method that can be used to enhance the neutron radiography image for objects with high scattering materials like hydrogen, carbon and other light materials. This method uses the Monte Carlo code, MCNP5, to simulate the neutron radiography process and get the flux distribution for each pixel of the image and determine the scattered neutrons distribution that causes the image blur and then subtract it from the initial image to improve its quality.

  19. Neutron scatter studies of chromatin structures related to functions

    International Nuclear Information System (INIS)

    Bradbury, E.M.

    1992-01-01

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

  20. The performance of neutron spectrometers AR a long-pulse spallation source

    International Nuclear Information System (INIS)

    Pynn, R.; Daemen, L.L.

    1995-01-01

    At a recent workshop at Lawrence Berkeley National Laboratory members of the international neutron scattering community discussed the performance to be anticipated from neutron scattering instruments installed at a 1 MW long-pulse spallation source (LPSS). Although the report of this workshop is long, its principal conclusions can be easily summarised and almost as easily understood. This article presents such a synthesis for a 60 Hz LPSS with 1 msec proton pulses. We discuss some of the limitations of the workshop conclusions and suggest a simple analysis of the performance differences that might be expected between short- and long-pulse sources both of which exploit coupled moderators

  1. Tritium solid targets for intense D-T neutron production and its related problems

    International Nuclear Information System (INIS)

    Sumita, Kenji

    1988-01-01

    This review paper is divided into three parts. Firstly, to attain an intense neutron production rate, the construction of a design with a higher tritium-containing surface and an effective cooling system like a rotating target device are discussed. The maximum attainable intensity based on tritium solid targets shall be estimated regarding planning for future D-T sources. Secondly, on the way to carry out some experiments, an absolute intensity calibration and an angular dependent neutron energy spectrum of the neutron source are essential parameters to analyse the results of the experiments. Sometimes the space dependent neutron spectrum is required as well as the space dependent neutron flux near the targets and irradiation samples. The measurement methods and their examples are reviewed for tritium solid targets. The third part is devoted to discuss the protection to tritium contamination problems due to unavoidable release of tritium gas from targets. Performance and effectiveness of tritium collection systems for intense D-T neutron sources shall be discussed in some examples. Tritium contamination incidents due to the faulted film powder of target surface are also reported in some real incident cases. (author). Abstract only

  2. Development and performance test of small angle neutron spectrometer at HANARO

    International Nuclear Information System (INIS)

    Han, Young Soo; Seong, Baek Seok; Lee, Chang Hee; Lee, Jeong Soo; Hong, Kwang Pyo; Choi, Byung Hoon; Choi, Young Hyun; Shin, Eun Joo; Park, Kook Nam

    2004-12-01

    The construction of Small Angle Neutron Spectrometer(SANS) at the CN beam port in HANARO was completed and has been opened to users in July 2001. the 2-D PSD (two dimensional position sensitive detector), the NVS (neutron velocity selector), the detector chamber rotation system, the detector horizontal moving system, the stepping motors, the beam shutter and the attenuator were fully tested and installed. The performance test of all the components was also completed. Wavelengths and resolutions of the neutron beam monochromatized by the NVS were calibrated using both the time-of-flight method and the diffraction measurement on standard material, the silver behenate. The relationship between the selector speed U[rpm] and the neutron wavelength λ[A] was obtained as λ[A]=0.11077+107171/U[rpm]. The controllers for the sample environments, the beam shutter and the stepping motors were constructed and its control programs for those controllers were also developed. The Beam test for the SANS has been finished and the characteristics of neutron beam was analyzed. The experimental methods of SANS and its data treatment method were established. The performance test of the HANARO SANS compared with that of foreign SANS's. shows that the HANARO SANS is quite well comparable with foreign SANS facilities

  3. Test Performance Related Dysfunctional Beliefs

    Directory of Open Access Journals (Sweden)

    Recep TÜTÜNCÜ

    2012-11-01

    Full Text Available Objective: Examinations by using tests are very frequently used in educational settings and successful studying before the examinations is a complex matter to deal with. In order to understand the determinants of success in exams better, we need to take into account not only emotional and motivational, but also cognitive aspects of the participants such as dysfunctional beliefs. Our aim is to present the relationship between candidates’ characteristics and distorted beliefs/schemata just before an examination. Method: The subjects of the study were 30 female and 30 male physicians who were about to take the medical specialization exam (MSE in Turkey. Dysfunctional Attitude Scale (DAS and Young Schema Questionnaire Short Form (YSQ-SF were applied to the subjects. The statistical analysis was done using the F test, Mann-Whitney, Kruskal-Wallis, chi-square test and spearman’s correlation test. Results: It was shown that some of the DAS and YSQ-SF scores were significantly higher in female gender, in the group who could not pass the exam, who had repetitive examinations, who had their first try taking an examination and who were unemployed at the time of the examination. Conclusion: Our findings indicate that candidates seeking help before MSE examination could be referred for cognitive therapy or counseling even they do not have any psychiatric diagnosis due to clinically significant cognitive distortion. Measurement and treatment of cognitive distortions that have negative impact on MSE performance may improve the cost-effectiveness and mental well being of the young doctors.

  4. Performance of the advanced cold neutron source and optics upgrades at the NIST Research Reactor

    International Nuclear Information System (INIS)

    Williams, R.E.; Kopetka, P.; Cook, J.C.; Rowe, J.M.

    2003-01-01

    On March 6, 2002, the NIST Research Reactor resumed routine operation following a six-month shutdown for facility upgrades and maintenance. During the shutdown, the original liquid hydrogen cold neutron source was removed, and the advanced cold source was installed. An optical filter was installed on one of the neutron guides, NG-3, replacing a crystal filter for the 30-m SANS instrument and the guide used between the chopper disks of the Disk Chopper time-of-flight Spectrometer (DCS) installed on NG-4 has been recently reconfigured. Additional improvements in the neutron optics of various instruments are being made. The advanced liquid hydrogen cold neutron source performs as expected, nearly doubling the flux available to most instruments. The measured gains range from about 1.4 at 2 A, to over a factor of two at 15 A. Also as expected, the heat load in the new source increased to 1200 watts, but the previously existing refrigerator has easily accommodated the increase. With intensity gains of a factor of two in the important long wavelength region of the spectrum, the advanced cold source significantly enhances the measurement capability of the cold neutron scattering instrumentation at NIST. The optical filter on NG-3 is also very successful; the 30-m SANS has an additional gain of two at 17 A. A system of refracting lenses and prisms near the SANS sample position has made possible measurements at low Q (0.0005 A -1 ) that were previously not feasible. The DCS has also seen additional intensity gain factors in excess of two for the majority of experiments and at short neutron wavelengths the gains exceed three. In addition, two new triple axis spectrometers will feature double-focusing monochromators in order to exploit the full size of the available thermal and cold neutron beam tubes. The success of the advanced cold source and enhanced neutron optics contributed to the recognition of the NIST Center for Neutron Research as 'the premiere neutron scattering

  5. Neutron radiography with ultracold neutrons

    International Nuclear Information System (INIS)

    Bates, J.C.

    1981-01-01

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

  6. Improved performances of 36 m small-angle neutron scattering spectrometer BATAN in Serpong Indonesia

    International Nuclear Information System (INIS)

    Putra, Edy Giri Rachman; Bharoto; Santoso, Eddy; Ikram, Abarrul

    2009-01-01

    SMARTer, a 36 m small-angle neutron scattering (SANS) spectrometer owned by the National Nuclear Energy Agency of Indonesia (BATAN) was installed at the Neutron Scattering Laboratory (NSL) in Serpong, Indonesia. Lots of works on replacing, upgrading and improving the control system, experimental methods, data collection and reduction in the last two years have been carried out to optimize the performance of SMARTer. Some standard samples such as silver behenate, monodisperse polystyrene nanoparticle, porous silica and block copolymer PS-PEP film were measured for the inter-laboratory comparison.

  7. RADIATION PERFORMANCE OF GAN AND INAS/GAAS QUANTUM DOT BASED DEVICES SUBJECTED TO NEUTRON RADIATION

    Directory of Open Access Journals (Sweden)

    Dhiyauddin Ahmad Fauzi

    2017-05-01

    Full Text Available In addition to their useful optoelectronics functions, gallium nitride (GaN and quantum dots (QDs based structures are also known for their radiation hardness properties. With demands on such semiconductor material structures, it is important to investigate the differences in reliability and radiation hardness properties of these two devices. For this purpose, three sets of GaN light-emitting diode (LED and InAs/GaAs dot-in-a well (DWELL samples were irradiated with thermal neutron of fluence ranging from 3×1013 to 6×1014 neutron/cm2 in PUSPATI TRIGA research reactor. The radiation performances for each device were evaluated based on the current-voltage (I-V and capacitance-voltage (C-V electrical characterisation method. Results suggested that the GaN based sample is less susceptible to electrical changes due to the thermal neutron radiation effects compared to the QD based sample.

  8. Flux Gain for Next-Generation Neutron-Scattering Instruments Resulting From Improved Supermirror Performance

    International Nuclear Information System (INIS)

    Rehm, C.

    2001-01-01

    Next-generation spallation neutron source facilities will offer instruments with unprecedented capabilities through simultaneous enhancement of source power and usage of advanced optical components. The Spallation Neutron Source (SNS), already under construction at Oak Ridge National Laboratory and scheduled to be completed by 2006, will provide greater than an order of magnitude more effective source flux than current state-of-the-art facilities, including the most advanced research reactors. An additional order of magnitude gain is expected through the use of new optical devices and instrumentation concepts. Many instrument designs require supermirror (SM) neutron guides with very high critical angles for total reflection. In this contribution, they discuss how the performance of modern neutron scattering instruments depends on the efficiency of these supermirrors. They outline ideas for enhancing the performance of the SM coatings, particularly for improving the reflectivity at the position of the critical wave vector transfer. A simulation program has been developed which allows different approaches for SM designs to be studied. Possible instrument performance gains are calculated for the example of the SNS reflectometer

  9. Performance of a MICROMEGAS-based TPC in a high-energy neutron beam

    Science.gov (United States)

    Snyder, L.; Manning, B.; Bowden, N. S.; Bundgaard, J.; Casperson, R. J.; Cebra, D. A.; Classen, T.; Duke, D. L.; Gearhart, J.; Greife, U.; Hagmann, C.; Heffner, M.; Hensle, D.; Higgins, D.; Isenhower, D.; King, J.; Klay, J. L.; Geppert-Kleinrath, V.; Loveland, W.; Magee, J. A.; Mendenhall, M. P.; Sangiorgio, S.; Seilhan, B.; Schmitt, K. T.; Tovesson, F.; Towell, R. S.; Walsh, N.; Watson, S.; Yao, L.; Younes, W.

    2018-02-01

    The MICROMEGAS (MICRO-MEsh GAseous Structure) charge amplification structure has found wide use in many detection applications, especially as a gain stage for the charge readout of Time Projection Chambers (TPCs). Here we report on the behavior of a MICROMEGAS TPC when operated in a high-energy (up to 800 MeV) neutron beam. It is found that neutron-induced reactions can cause discharges in some drift gas mixtures that are stable in the absence of the neutron beam. The discharges result from recoil ions close to the MICROMEGAS that deposit high specific ionization density and have a limited diffusion time. For a binary drift gas, increasing the percentage of the molecular component (quench gas) relative to the noble component and operating at lower pressures generally improves stability.

  10. Neutron star radii, universal relations, and the role of prior distributions

    Energy Technology Data Exchange (ETDEWEB)

    Steiner, A.W. [University of Tennessee, Department of Physics and Astronomy, Knoxville, TN (United States); Oak Ridge National Laboratory, Physics Division, Oak Ridge, TN (United States); Lattimer, J.M. [Stony Brook University, Dept. of Physics and Astronomy, Stony Brook, NY (United States); Brown, E.F. [Michigan State University, Department of Physics and Astronomy, East Lansing, MI (United States); Michigan State University, The Joint Institute for Nuclear Astrophysics-Center for the Evolution of the Elements, East Lansing, MI (United States); Michigan State University, National Superconducting Cyclotron Laboratory, East Lansing, MI (United States)

    2016-02-15

    We investigate constraints on neutron star structure arising from the assumptions that neutron stars have crusts, that recent calculations of pure neutron matter limit the equation of state of neutron star matter near the nuclear saturation density, that the high-density equation of state is limited by causality and the largest high-accuracy neutron star mass measurement, and that general relativity is the correct theory of gravity. We explore the role of prior assumptions by considering two classes of equation of state models. In a first, the intermediate- and high-density behavior of the equation of state is parameterized by piecewise polytropes. In the second class, the high-density behavior of the equation of state is parameterized by piecewise continuous line segments. The smallest density at which high-density matter appears is varied in order to allow for strong phase transitions above the nuclear saturation density. We critically examine correlations among the pressure of matter, radii, maximum masses, the binding energy, the moment of inertia, and the tidal deformability, paying special attention to the sensitivity of these correlations to prior assumptions about the equation of state. It is possible to constrain the radii of 1.4M {sub CircleDot} neutron stars to be larger than 10 km, even without consideration of additional astrophysical observations, for example, those from photospheric radius expansion bursts or quiescent low-mass X-ray binaries. We are able to improve the accuracy of known correlations between the moment of inertia and compactness as well as the binding energy and compactness. We also demonstrate the existence of a correlation between the neutron star binding energy and the moment of inertia. (orig.)

  11. The neutronic and fuel cycle performance of interchangeable 3500 MWth metal and oxide fueled LMRs

    International Nuclear Information System (INIS)

    Fujita, E.K.; Wade, D.C.

    1990-01-01

    This study summarizes the neutronic and fuel cycle analysis performed at Argonne National Laboratory for an oxide and a metal fueled 3500 MWth LMR. These reactor designs formed the basis for a joint US/European study of LMR ATWS events. The oxide and metal core designs were developed to meet reactor performance specifications that are constrained by requirements for core loading interchangeability and for a small burnup reactivity swing. Differences in the computed performance parameters of the oxide and metal cores, arising from basic differences in their neutronic characteristics, are identified and discussed. It is shown that metal and oxide cores designed to the same ground rules exhibit many similar performance characteristics; however, they differ substantially in reactivity coefficients, control strategies, and fuel cycle options. 12 refs., 2 figs., 12 tabs

  12. Performance test of micro-fission chambers for in-vessel neutron monitoring of ITER

    International Nuclear Information System (INIS)

    Yamauchi, Michinori; Nishitani, Takeo; Ochiai, Kentaro; Morimoto, Yuichi; Hori, Jun-ichi; Ebisawa, Katsuyuki; Kasai, Satoshi

    2002-03-01

    A micro-fission chamber with 12 mg UO 2 and a dummy chamber without uranium were fabricated and the performance was tested. They are designed to be installed inside the vacuum vessel of the compact ITER (ITER-FEAT) for neutron monitoring. The vacuum leak rate of the dummy chamber with MI cable, resistances of chambers between central conductor and outer sheath, and mechanical strength up to 50G acceleration were confirmed to meet the design criteria. The gamma-ray sensitivity was measured for the dummy chamber with the 60 Co gamma-ray irradiation facility at JAERI Takasaki. The output signals for gamma-rays in Campbelling mode were estimated to be less than 0.1% of those by neutrons at the location behind the blanket module in ITER-FEAT. The detector response for 14 MeV neutrons was investigated with the FNS facility. Excellent linearity between count rates, square of Campbelling voltage and neutron fluxes was confirmed in the temperature range from 20degC (room) to 250degC. However, a positive dependence of 14 MeV neutron count rates on temperature was observed, which might be caused by the increase in the pulse height with temperature rise. Effects of a change of surrounding materials were evaluated by the sensitivity measurements of the micro-fission chamber inserted into the shielding blanket mock-up. The sensitivity was enhanced by slow-downed neutrons, which agreed with the calculation result by MCNP-4C code. As a result, it was concluded that the developed micro-fission chamber is applicable for ITER-FEAT. (author)

  13. Studies Performed in Preparation for the Spallation Neutron Source Accumulator Ring Commissioning

    CERN Document Server

    Cousineau, Sarah M; Henderson, Stuart; Holmes, Jeffrey Alan; Plum, Michael

    2005-01-01

    The Spallation Neutron Source accumulator ring will compress 1.5?1014, 1 GeV protons from a 1 ms bunch train to a single 695 ns proton bunch for use in neutron spallation. Due to the high beam power, unprecedented control of beam loss will be required in order to control radiation and allow for hands-on maintenance in most areas of the ring. A number of detailed investigations have been performed to understand the primary sources of beam loss and to predict and mitigate problems associated with radiation hot spots in the ring. The ORBIT particle tracking code is used to perform realistic simulations of the beam accumulation in the ring, including detailed modeling of the injection system, transport through the measured magnet fields including higher order multipoles, and beam loss and collimation. In this paper we present the results of a number of studies performed in preparation for the 2006 commissioning of the accumulator ring.

  14. Relation between proton and neutron asymptotic normalization coefficients for light mirror nuclei and its relevance for nuclear astrophysics

    International Nuclear Information System (INIS)

    Timofeyuk, N.K.; Johnson, R.C.; Descouvemont, P.

    2006-01-01

    It has been realised recently that charge symmetry of the nucleon-nucleon interaction leads to a certain relation between Asymptotic Normalization Coefficients (ANCs) in mirror-conjugated one-nucleon overlap integrals. This relation can be approximated by a simple analytical formula that involves mirror neutron and proton separation energies, the core charge and the range of the strong nucleon-core interaction. We perform detailed microscopic multi-channel cluster model calculations and compare their predictions to the simple analytical formula as well as to calculations within a single-particle model in which mirror symmetry in potential wells and spectroscopic factors are assumed. The validity of the latter assumptions is verified on the basis of microscopic cluster model calculations. For mirror pairs in which one of the states is above the proton decay threshold, a link exists between the proton partial width and the ANC of the mirror neutron. This link is given by an approximate analytical formula similar to that for a bound-bound mirror pair. We compare predictions of this formula to the results of microscopic cluster model calculations. Mirror symmetry in ANCs can be used to predict cross sections for proton capture at stellar energies using neutron ANCs measured with stable or ''less radioactive'' beams. (orig.)

  15. Long-term performance of the CANDU-type of vanadium self-powered neutron detectors in NRU

    Energy Technology Data Exchange (ETDEWEB)

    Leung, T.C. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)]. E-mail: leungt@aecl.ca

    2007-07-01

    The CANDU-type of in-core vanadium self-powered neutron flux detectors have been installed in NRU to monitor the axial neutron flux distributions adjacent to the loop fuel test sites since 1996. This paper describes how the thermal neutron fluxes were measured at two monitoring sites, and presents a method of correcting the vanadium burn-up effect, which can be up to 2 to 3% per year, depending on the detector locations in the reactor. It also presents the results of measurements from neutron flux detectors that have operated for over eight-years in NRU. There is good agreement between the measured and simulated neutron fluxes, to within {+-} 6.5%, and the long-term performance of the CANDU-type of vanadium neutron flux detectors in NRU is satisfactory. (author)

  16. EJ-309 pulse shape discrimination performance with a high gamma-ray-to-neutron ratio and low threshold

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, A.C., E-mail: Alexis.C.Kaplan@gmail.com [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Blvd., Ann Arbor, MI 48104 (United States); Nuclear Engineering and Nonproliferation Division, Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Flaska, M.; Enqvist, A.; Dolan, J.L.; Pozzi, S.A. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Blvd., Ann Arbor, MI 48104 (United States)

    2013-11-21

    Measuring neutrons in the presence of high gamma-ray fluence is a challenge with multi-particle detectors. Organic liquid scintillators such as the EJ-309 are capable of accurate pulse-shape discrimination (PSD) but the chance for particle misclassification is not negligible for some applications. By varying the distance from an EJ-309 scintillator to a strong-gamma-ray source and keeping a weak-neutron source at a fixed position, various gamma-to-neutron ratios can be measured and PSD performance can be quantified. Comparing neutron pulse-height distributions allows for pulse-height specific PSD evaluation, and quantification and visualization of deviation from {sup 252}Cf alone. Even with the addition of the misclassified gamma-rays, the PSD is effective in separating particles so that neutron count rate can be predicted with less than 10% error up to a gamma-to-neutron ratio of almost 650. For applications which can afford a reduction in neutron detection efficiency, PSD can be sufficiently effective in discriminating particles to measure a weak neutron source in a high gamma-ray background. -- Highlights: •We measure neutrons in a high photon background with EJ-309 liquid scintillators. •A low threshold is used to test the limits of particle discrimination. •A weak neutron signal is detectable with a gamma/neutron ratio as high as 770. •Photon pileup most commonly adds to error in classification of neutrons. •Neutron count rates are within 10% of expected rate under high gamma background.

  17. EJ-309 pulse shape discrimination performance with a high gamma-ray-to-neutron ratio and low threshold

    International Nuclear Information System (INIS)

    Kaplan, A.C.; Flaska, M.; Enqvist, A.; Dolan, J.L.; Pozzi, S.A.

    2013-01-01

    Measuring neutrons in the presence of high gamma-ray fluence is a challenge with multi-particle detectors. Organic liquid scintillators such as the EJ-309 are capable of accurate pulse-shape discrimination (PSD) but the chance for particle misclassification is not negligible for some applications. By varying the distance from an EJ-309 scintillator to a strong-gamma-ray source and keeping a weak-neutron source at a fixed position, various gamma-to-neutron ratios can be measured and PSD performance can be quantified. Comparing neutron pulse-height distributions allows for pulse-height specific PSD evaluation, and quantification and visualization of deviation from 252 Cf alone. Even with the addition of the misclassified gamma-rays, the PSD is effective in separating particles so that neutron count rate can be predicted with less than 10% error up to a gamma-to-neutron ratio of almost 650. For applications which can afford a reduction in neutron detection efficiency, PSD can be sufficiently effective in discriminating particles to measure a weak neutron source in a high gamma-ray background. -- Highlights: •We measure neutrons in a high photon background with EJ-309 liquid scintillators. •A low threshold is used to test the limits of particle discrimination. •A weak neutron signal is detectable with a gamma/neutron ratio as high as 770. •Photon pileup most commonly adds to error in classification of neutrons. •Neutron count rates are within 10% of expected rate under high gamma background

  18. Biological effects of neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Ogiu, Toshiaki; Ohmachi, Yasushi; Ishida, Yuka [National Inst. of Radiological Sciences, Chiba (JP)] [and others

    2003-03-01

    Although the occasion to be exposed to neutrons is rare in our life, except for nuclear accidents like in the critical accident at Tokai-mura in 1999, countermeasures against accident should be always prepared. In the Tokai-mura accident, residents received less than 21 mSv of neutrons and gamma rays. The cancer risks and fetal effects of low doses of neutrons were matters of concern among residents. The purpose of this program is to investigate the relative biological effectiveness (RBE) for leukemias, and thereby to assess risks of neutrons. Animal experiments are planed to obtain the following RBEs: (1) RBE for the induction of leukemias in mice and (2) RBE for effects on fetuses. Cyclotron fast neutrons (10 MeV) and electrostatic accelerator-derived neutrons (2 MeV) are used for exposure in this program. Furthermore, cytological and cytogenetic analyses will be performed. (author)

  19. Energy dependence of relative abundances and periods of delayed neutron separate groups from neutron induced fission of 239Pu in the virgin neutron energy range 0.37-4.97 MeV

    International Nuclear Information System (INIS)

    Piksajkin, V.M.; Kazakov, L.E.; Isaev, S.T.; Korolev, G.G.; Roshchenko, V.A.; Tertychnyj, R.G.

    2002-01-01

    Relative yield and group period of delayed neutrons induced by the 239 Pu fission in the 0.37-4.97 MeV range were measured. Comparative analysis of experimental data was conducted in terms of middle period of half-life of delayed neutron nuclei-precursors. Character and scale of changing values of delayed neutron group parameters as changing excitation energy of fission compound-nucleus have been demonstrated for the first time. Considerable energy dependence of group parameters under the neutron induced 239 Pu fission that was expressed by the decreasing middle period of half-life of nuclei-precursors by 10 % in the 2.85 eV - 5 MeV range of virgin neutrons was detected [ru

  20. Low-mass neutron stars: universal relations, the nuclear symmetry energy and gravitational radiation

    Science.gov (United States)

    O. Silva, Hector; Berti, Emanuele; Sotani, Hajime

    2016-03-01

    Compact objects such as neutron stars are ideal astrophysical laboratories to test our understanding of the fundamental interactions in the regime of supranuclear densities, unachievable by terrestrial experiments. Despite recent progress, the description of matter (i.e., the equation of state) at such densities is still debatable. This translates into uncertainties in the bulk properties of neutron stars, masses and radii for instance. Here we will consider low-mass neutron stars. Such stars are expected to carry important information on nuclear matter near the nuclear saturation point. It has recently been shown that the masses and surface redshifts of low-mass neutron stars smoothly depend on simple functions of the central density and of a characteristic parameter η associated with the choice of equation of state. Here we extend these results to slowly-rotating and tidally deformed stars and obtain empirical relations for various quantities, such as the moment of inertia, quadrupole moment and ellipticity, tidal and rotational Love numbers, and rotational apsidal constants. We discuss how these relations might be used to constrain the equation of state by future observations in the electromagnetic and gravitational-wave spectra.

  1. Parametric neutronic analyses related to burnup credit cask design

    International Nuclear Information System (INIS)

    Parks, C.V.

    1989-01-01

    The consideration of spent fuel histories (burnup credit) in the design of spent fuel shipping casks will result in cost savings and public risk benefits in the overall fuel transportation system. The purpose of this paper is to describe the depletion and criticality analyses performed in conjunction with and supplemental to the referenced analysis. Specifically, the objectives are to indicate trends in spent fuel isotopic composition with burnup and decay time; provide spent fuel pin lattice values as a function of burnup, decay time, and initial enrichment; demonstrate the variation of k eff for infinite arrays of spent fuel assemblies separated by generic cask basket designs (borated and unborated) of varying thicknesses; and verify the potential cask reactivity margin available with burnup credit via analysis with generic cask models

  2. Effectively universal behavior of rotating neutron stars in general relativity makes them even simpler than their Newtonian counterparts.

    Science.gov (United States)

    Pappas, George; Apostolatos, Theocharis A

    2014-03-28

    Recently, it was shown that slowly rotating neutron stars exhibit an interesting correlation between their moment of inertia I, their quadrupole moment Q, and their tidal deformation Love number λ (the I-Love-Q relations), independently of the equation of state of the compact object. In the present Letter a similar, more general, universality is shown to hold true for all rotating neutron stars within general relativity; the first four multipole moments of the neutron star are related in a way independent of the nuclear matter equation of state we assume. By exploiting this relation, we can describe quite accurately the geometry around a neutron star with fewer parameters, even if we don't know precisely the equation of state. Furthermore, this universal behavior displayed by neutron stars could promote them to a more promising class of candidates (next to black holes) for testing theories of gravity.

  3. Design and performance of vacuum capable detector electronics for linear position sensitive neutron detectors

    International Nuclear Information System (INIS)

    Riedel, R.A.; Cooper, R.G.; Funk, L.L.; Clonts, L.G.

    2012-01-01

    We describe the design and performance of electronics for linear position sensitive neutron detectors. The eight tube assembly requires 10 W of power and can be controlled via digital communication links. The electronics can be used without modification in vacuum. Using a transimpedance amplifier and gated integration, we achieve a highly linear system with coefficient of determinations of 0.9999 or better. Typical resolution is one percent of tube length.

  4. Design and performance of vacuum capable detector electronics for linear position sensitive neutron detectors

    Energy Technology Data Exchange (ETDEWEB)

    Riedel, R.A., E-mail: riedelra@ornl.gov [Oak Ridge National Laboratories, Oak Ridge, TN 37830 (United States); Cooper, R.G.; Funk, L.L.; Clonts, L.G. [Oak Ridge National Laboratories, Oak Ridge, TN 37830 (United States)

    2012-02-01

    We describe the design and performance of electronics for linear position sensitive neutron detectors. The eight tube assembly requires 10 W of power and can be controlled via digital communication links. The electronics can be used without modification in vacuum. Using a transimpedance amplifier and gated integration, we achieve a highly linear system with coefficient of determinations of 0.9999 or better. Typical resolution is one percent of tube length.

  5. Thermal Performance and Operation Limit of Heat Pipe Containing Neutron Absorber

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyung Mo; Jeong, Yeong Shin; Kim, In Guk; Bang, In Choel [UNIST, Ulsan (Korea, Republic of)

    2015-05-15

    Recently, passive safety systems are under development to ensure the core cooling in accidents involving impossible depressurization such as station blackout (SBO). Hydraulic control rod drive mechanisms, passive auxiliary feedwater system (PAFS), Passive autocatalystic recombiner (PAR), and so on are types of passive safety systems to enhance the safety of nuclear power plants. Heat pipe is used in various engineering fields due to its advantages in terms of easy fabrication, high heat transfer rate, and passive heat transfer. Also, the various concepts associated with safety system and heat transfer using the heat pipe were developed in nuclear engineering field.. Thus, our group suggested the hybrid control rod which combines the functions of existing control rod and heat pipe. If there is significant temperature difference between active core and condenser, the hybrid control rod can shutdown the nuclear fission reaction and remove the decay heat from the core to ultimate heat sink. The unique characteristic of the hybrid control rod is the presence of neutron absorber inside the heat pipe. Many previous researchers studied the effect of parameters on the thermal performance of heat pipe. However, the effect of neutron absorber on the thermal performance of heat pipe has not been investigated. Thus, the annular heat pipe which contains B{sub 4}C pellet in the normal heat pipe was prepared and the thermal performance of the annular heat pipe was studied in this study. Hybrid control rod concept was developed as a passive safety system of nuclear power plant to ensure the safety of the reactor at accident condition. The hybrid control rod must contain the neutron absorber for the function as a control rod. So, the effect of neutron absorber on the thermal performance of heat pipe was experimentally investigated in this study. Temperature distributions at evaporator section of annular heat pipe were lower than normal heat pipe due to the larger volume occupied by

  6. A high performance neutron powder diffractometer at 3 MW Triga Mark-II research reactor in Bangladesh

    Energy Technology Data Exchange (ETDEWEB)

    Kamal, I., E-mail: imtiaz-kamal26@yahoo.com; Yunus, S. M., E-mail: yunussm11@yahoo.com; Datta, T. K., E-mail: tk-datta4@yahoo.com; Zakaria, A. K. M.; Das, A. K.; Aktar, S.; Hossain, S. [Institute of Nuclear Science and Technology, Atomic Energy Research Establishment, Ganakbari, Savar, Dhaka (Bangladesh); Berliner, R., E-mail: RB@instrumentationAssociates.com [Instrumentation Associates, Durham, North Carolina (United States); Yelon, W. B., E-mail: yelonwb@hotmail.com [Oak Ridge National Laboratory, Oak Ridge, Tennessee (United States)

    2016-07-12

    A high performance neutron diffractometer called Savar Neutron Diffractometer (SAND) was built and installed at radial beam port-2 of TRIGA Mark II research reactor at AERE, Savar, Dhaka, Bangladesh. Structural studies of materials are being done by this technique to characterize materials crystallograpohically and magnetically. The micro-structural information obtainable by neutron scattering method is very essential for determining its technological applications. This technique is unique for understanding the magnetic behavior in magnetic materials. Ceramic, steel, electronic and electric industries can be benefited from this facility for improving their products and fabrication process. This instrument consists of a Popovicimonochromator with a large linear position sensitive detector array. The monochromator consists of nine blades of perfect single crystal of silicon with 6 mm thickness each. The monochromator design was optimized to provide maximum flux on 3 mm diameter cylindrical sample with a relatively flat angular dependence of resolution. Five different wave lengths can be selected by orienting the crystal at various angles. A sapphire filter was used before the primary collimator to minimize the first neutron. The detector assembly is composed of 15 linear position sensitive proportional counters placed at either 1.1 m or 1.6 m from the sample position and enclosed in a air pad supported high density polythene shield. Position sensing is obtained by charge division using 1-wide NIM position encoding modules (PEM). The PEMs communicate with the host computer via USB. The detector when placed at 1.1 m, subtends 30° (2θ) at each step and covers 120° in 4 steps. When the detector is placed at 1.6 m it subtends 20° at each step and covers 120° in 6 steps. The instrument supports both low and high temperature sample environment. The instrument supports both low and high temperature sample environment. The diffractometer is a state-of-the art technology

  7. A comparison of back propagation and Generalized Regression Neural Networks performance in neutron spectrometry.

    Science.gov (United States)

    Martínez-Blanco, Ma Del Rosario; Ornelas-Vargas, Gerardo; Solís-Sánchez, Luis Octavio; Castañeda-Miranada, Rodrigo; Vega-Carrillo, Héctor René; Celaya-Padilla, José M; Garza-Veloz, Idalia; Martínez-Fierro, Margarita; Ortiz-Rodríguez, José Manuel

    2016-11-01

    The process of unfolding the neutron energy spectrum has been subject of research for many years. Monte Carlo, iterative methods, the bayesian theory, the principle of maximum entropy are some of the methods used. The drawbacks associated with traditional unfolding procedures have motivated the research of complementary approaches. Back Propagation Neural Networks (BPNN), have been applied with success in neutron spectrometry and dosimetry domains, however, the structure and learning parameters are factors that highly impact in the networks performance. In ANN domain, Generalized Regression Neural Network (GRNN) is one of the simplest neural networks in term of network architecture and learning algorithm. The learning is instantaneous, requiring no time for training. Opposite to BPNN, a GRNN would be formed instantly with just a 1-pass training on the development data. In the network development phase, the only hurdle is to optimize the hyper-parameter, which is known as sigma, governing the smoothness of the network. The aim of this work was to compare the performance of BPNN and GRNN in the solution of the neutron spectrometry problem. From results obtained it can be observed that despite the very similar results, GRNN performs better than BPNN. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. A comparison of back propagation and generalized regression neural networks performance in neutron spectrometry

    International Nuclear Information System (INIS)

    Ortiz R, J. M.; Martinez B, M. R.; Solis S, L. O.; Castaneda M, R.; Vega C, H. R.

    2015-10-01

    The process of unfolding the neutron energy spectrum has been the subject of research for many years. Monte Carlo, iterative methods, the bayesian theory, the principle of maximum entropy are some of the methods used. The drawbacks associated with traditional unfolding procedures have motivated the need of complementary approaches. Back Propagation Neural Networks (BPNN), have been applied with success in the neutron spectrometry and dosimetry domains, however, the structure and the learning parameters are factors that contribute in a significant way in the networks performance. In artificial neural network domain, Generalized Regression Neural Network (GRNN) is one of the simplest neural networks in term of network architecture and learning algorithm. The learning is instantaneous, which mean require no time for training. Opposite to BPNN, a GRNN would be formed instantly with just a 1-pass training with the development data. In the network development phase, the only hurdle is to tune the hyper parameter, which is known as sigma, governing the smoothness of the network. The aim of this work was to compare the performance of BPNN and GRNN in the solution of the neutron spectrometry problem. From results obtained can be observed that despite the very similar results, GRNN performs better than BPNN. (Author)

  9. Performance assessment of imaging plates for the JHR transfer Neutron Imaging System

    Science.gov (United States)

    Simon, E.; Guimbal, P. AB(; )

    2018-01-01

    The underwater Neutron Imaging System to be installed in the Jules Horowitz Reactor (JHR-NIS) is based on a transfer method using a neutron activated beta-emitter like Dysprosium. The information stored in the converter is to be offline transferred on a specific imaging system, still to be defined. Solutions are currently under investigation for the JHR-NIS in order to anticipate the disappearance of radiographic films commonly used in these applications. We report here the performance assessment of Computed Radiography imagers (Imaging Plates) performed at LLB/Orphée (CEA Saclay). Several imaging plate types are studied, in one hand in the configuration involving an intimate contact with an activated dysprosium foil converter: Fuji BAS-TR, Fuji UR-1 and Carestream Flex XL Blue imaging plates, and in the other hand by using a prototypal imaging plate doped with dysprosium and thus not needing any contact with a separate converter foil. The results for these imaging plates are compared with those obtained with gadolinium doped imaging plate used in direct neutron imaging (Fuji BAS-ND). The detection performances of the different imagers are compared regarding resolution and noise. The many advantages of using imaging plates over radiographic films (high sensitivity, linear response, high dynamic range) could palliate its lower intrinsic resolution.

  10. A comparison of back propagation and Generalized Regression Neural Networks performance in neutron spectrometry

    International Nuclear Information System (INIS)

    Martínez-Blanco, Ma. del Rosario

    2016-01-01

    The process of unfolding the neutron energy spectrum has been subject of research for many years. Monte Carlo, iterative methods, the bayesian theory, the principle of maximum entropy are some of the methods used. The drawbacks associated with traditional unfolding procedures have motivated the research of complementary approaches. Back Propagation Neural Networks (BPNN), have been applied with success in neutron spectrometry and dosimetry domains, however, the structure and learning parameters are factors that highly impact in the networks performance. In ANN domain, Generalized Regression Neural Network (GRNN) is one of the simplest neural networks in term of network architecture and learning algorithm. The learning is instantaneous, requiring no time for training. Opposite to BPNN, a GRNN would be formed instantly with just a 1-pass training on the development data. In the network development phase, the only hurdle is to optimize the hyper-parameter, which is known as sigma, governing the smoothness of the network. The aim of this work was to compare the performance of BPNN and GRNN in the solution of the neutron spectrometry problem. From results obtained it can be observed that despite the very similar results, GRNN performs better than BPNN.

  11. A comparison of back propagation and generalized regression neural networks performance in neutron spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz R, J. M.; Martinez B, M. R.; Solis S, L. O.; Castaneda M, R. [Universidad Autonoma de Zacatecas, Unidad Academica de Ingenieria Electrica, Av. Ramon Lopez Velarde 801, Col. Centro, 98000 Zacatecas, Zac. (Mexico); Vega C, H. R., E-mail: morvymm@yahoo.com.mx [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)

    2015-10-15

    The process of unfolding the neutron energy spectrum has been the subject of research for many years. Monte Carlo, iterative methods, the bayesian theory, the principle of maximum entropy are some of the methods used. The drawbacks associated with traditional unfolding procedures have motivated the need of complementary approaches. Back Propagation Neural Networks (BPNN), have been applied with success in the neutron spectrometry and dosimetry domains, however, the structure and the learning parameters are factors that contribute in a significant way in the networks performance. In artificial neural network domain, Generalized Regression Neural Network (GRNN) is one of the simplest neural networks in term of network architecture and learning algorithm. The learning is instantaneous, which mean require no time for training. Opposite to BPNN, a GRNN would be formed instantly with just a 1-pass training with the development data. In the network development phase, the only hurdle is to tune the hyper parameter, which is known as sigma, governing the smoothness of the network. The aim of this work was to compare the performance of BPNN and GRNN in the solution of the neutron spectrometry problem. From results obtained can be observed that despite the very similar results, GRNN performs better than BPNN. (Author)

  12. Performance of IPEN/CNEN-SP Neutron Activation Analysis Laboratory for microelement determinations in proficiency testing

    International Nuclear Information System (INIS)

    Armelin, Maria Jose A.; Saiki, Mitiko; Souza, Gilberto B. de; Nogueira, Ana Rita A.

    2009-01-01

    The performance of Neutron Activation Laboratory, IPEN - CNEN/SP, was evaluated for the Ca, Fe, K, Mn, Na and Zn determinations in animal feed samples for ruminants through a proficiency test (PT) program. This PT program is organized by EMBRAPA Cattle Southeast to evaluate laboratories that analyze animal feed samples. Considering the fractions of satisfactory z-scores (%) of evaluated analytes to determine the laboratories performance, the general performance indicator obtained by IPEN - CNEN/SP ranged from 90 to 95% of the satisfactory results during the period of participation in the evaluation, four years. (author)

  13. Neutronic performance of decoupled poisoned and unpoisoned composite moderators for high resolution experiments

    International Nuclear Information System (INIS)

    Kai, Tetsuya; Harada, Masahide; Watanabe, Noboru; Teshigawara, Makoto; Sakata, Hideaki; Ikeda, Yujiro

    2001-01-01

    We studied decoupled poisoned and un-poisoned composite moderators consisting of 20 mm thick hydrogen and 30 mm thick light water. The neutron pulses from un-poisoned one were much broader with longer decay times than a simple decoupled hydrogen moderator in 50 mm thickness. It was also found that the poisoned composite moderator provides higher pulse peak intensities relative to the hydrogen moderator (poisoned at 20 mm) below several tens meV with no penalty of pulse width. (author)

  14. Performance Related Pay and Labor Productivity

    NARCIS (Netherlands)

    Gielen, A. C.; Kerkhofs, M.J.M.; van Ours, J.C.

    2006-01-01

    This paper uses information from a panel of Dutch firms to investigate the labor productivity effects of performance related pay (PRP).We find that PRP increases labor productivity at the firm level with about 9%.

  15. Performance Related Pay and Labour Productivity

    OpenAIRE

    Gielen, Anne; Kerkhofs, Marcel J M; van Ours, Jan C

    2006-01-01

    This paper uses information from a panel of Dutch firms to investigate the labour productivity effects of performance related pay (PRP). We find that PRP increases labour productivity at the firm level with about 9%.

  16. Relative biological effectiveness measurements using murine lethality and survival of intestinal and hematopoietic stem cells after Fermilab neutrons compared to JANUS reactor neutrons and 60Co gamma rays

    International Nuclear Information System (INIS)

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

    1984-01-01

    The relative biological effectiveness (RBE) of the 25-MeV (average energy) neutron beam at the Fermi National Accelerator Laboratory was measured using murine bone marrow (LD/sub 50/30/) and gut (LD/sub 50/6/) lethality and killing of hematopoietic colony forming units (CFU-S) or intestinal clonogenic cells (ICC). The LD/sub 50/30/ and LD/sub 50/6/ for mice exposed to the Fermilab neutron beam were 6.6 and 8.7 Gy, respectively, intermediate between those of JANUS neutrons and 60 Co γ rays. The D 0 values for CFU-S and ICC were 47 cGy and 1.05 Gy, respectively, also intermediate between the lowest values found for JANUS neutrons and the highest values found after 60 Co γ rays. The split-dose survival ratios for CFU-S at intervals of 1-6 hr between doses were essentially 1.0 for both neutron sources. The 3-hr split-dose survival ratios for ICC were 1.0 for JANUS neutrons, 1.85 for Fermilab neutrons, and 6.5 for 60 Co γ rays. The RBE estimates for LD/sub 50/30/ were 1.5 and 2.3 for Fermilab and JANUS neutrons, respectively. Based on LD/sub 50/6/, the RBEs were 1.9 (Fermilab) and 3.0 (JANUS). The RBEs for CFU-S D 0 were 1.4 (Fermilab) and 1.9 (JANUS) and for jejunal microcolony D 0 1.4 (Fermilab) and 2.8 (JANUS)

  17. Related party transactions and firms financial performance ...

    African Journals Online (AJOL)

    Related party transactions and firms financial performance. ... African Research Review ... financial performance using Secondary data obtained from Nigeria stock ... on Asset, Return on Equity and Earnings per share of manufacturing firms. ... Result showed RPT has no significant effects on ROA and EPS and not used to ...

  18. Relating Performative and Ostensive Management Accounting Research

    DEFF Research Database (Denmark)

    Hansen, Allan

    2011-01-01

    . Findings – The paper illustrates how the process is a balancing act. On the one hand, it requires performative researchers to relate more closely to aspects decisive for ostensive researchers; yet, on the other, they need to preserve the distinctiveness of the performative approach. Originality....../value – This paper exemplifies these issues with reference to management accounting research and contributes by clarifying the methodological implications of moving performative research closer to ostensive research....

  19. Effect of Target Configuration on the Neutronic Performance of the Gas-Cooled ADS

    CERN Document Server

    Biss, K; Shetty, N; Nabbi, R

    2013-01-01

    With the utilization of nuclear energy transuranic elements like Pu, Am and Cm are produced causing high, long term radioactivity and radio toxicity, respectively. To reduce the radiological impact on the environment and to the repository Partitioning and Transmutation is considered as an efficient way. In this respect comprehensive research works are performed at different research institutes worldwide. The results show that the transmutation of TRU is achieved with fast neutrons due to the higher fission probability. Based on Accelerator Driven Systems (ADS) those neutrons are used in a particular system, in which mainly liquid metal eutectic (lead bismuth) is used as coolant. The neutronic performance of an ADS system based on gas cooling was studied in this work by using the simulation tool MCNPX. The usage of the Monte-Carlo method in MCNPX allows the simulation of the physical processes in a 3D-model of the core. In dependence of the spallation target material and design several parameters like the mult...

  20. Comparison of calculations with neutron dosimetry measurements performed at the Oak Ridge Poolside Facility

    Energy Technology Data Exchange (ETDEWEB)

    Maerker, R.E.; Williams, M.L.

    1981-01-01

    The Oak Ridge Poolside Facility (PSF), like the Pool Critical Assembly (PCA), is used for benchmark dosimetry measurements which can serve to validate the transport methods used in calculating the high-energy neutron fluences (> 0.1 MeV) in LWR pressure vessels required to estimate the neutron damage to the pressure vessels in the form of embrittlement. The PSF consists of an arrangement of two water gaps of 4 and 12 cm thickness separated by a simulated thermal shield and followed by a simulated pressure vessel wall and then a void box to represent a reactor cavity. The PSF is driven by the 30 MW ORR reactor, whereas the geometrically similar core of the PCA has a maximum power of only 10 KW. This paper reports the results of some calculated activities and compares them with published PSF measurements performed by HEDL and other laboratories on the so-called Westinghouse surveillance capsule perturbation experiment.

  1. Comparison of calculations with neutron dosimetry measurements performed at the Oak Ridge Poolside Facility

    International Nuclear Information System (INIS)

    Maerker, R.E.; Williams, M.L.

    1981-01-01

    The Oak Ridge Poolside Facility (PSF), like the Pool Critical Assembly (PCA), is used for benchmark dosimetry measurements which can serve to validate the transport methods used in calculating the high-energy neutron fluences (> 0.1 MeV) in LWR pressure vessels required to estimate the neutron damage to the pressure vessels in the form of embrittlement. The PSF consists of an arrangement of two water gaps of 4 and 12 cm thickness separated by a simulated thermal shield and followed by a simulated pressure vessel wall and then a void box to represent a reactor cavity. The PSF is driven by the 30 MW ORR reactor, whereas the geometrically similar core of the PCA has a maximum power of only 10 KW. This paper reports the results of some calculated activities and compares them with published PSF measurements performed by HEDL and other laboratories on the so-called Westinghouse surveillance capsule perturbation experiment

  2. Related Party Transactions and Firms Financial Performance

    African Journals Online (AJOL)

    Prof

    Chien and Hsu (2010) found a positive moderating effect of corporate governance on the related transactions-firm performance relationship and deduce that presence of corporate governance could 'transfer' related party transactions 'conflict- of-interest' to be efficient. Past studies on the impact of RPT on financial reporting ...

  3. Neutron star mergers as a probe of modifications of general relativity with finite-range scalar forces

    Science.gov (United States)

    Sagunski, Laura; Zhang, Jun; Johnson, Matthew C.; Lehner, Luis; Sakellariadou, Mairi; Liebling, Steven L.; Palenzuela, Carlos; Neilsen, David

    2018-03-01

    Observations of gravitational radiation from compact binary systems provide an unprecedented opportunity to test general relativity in the strong field dynamical regime. In this paper, we investigate how future observations of gravitational radiation from binary neutron star mergers might provide constraints on finite-range forces from a universally coupled massive scalar field. Such scalar degrees of freedom (d.o.f.) are a characteristic feature of many extensions of general relativity. For concreteness, we work in the context of metric f (R ) gravity, which is equivalent to general relativity and a universally coupled scalar field with a nonlinear potential whose form is fixed by the choice of f (R ). In theories where neutron stars (or other compact objects) obtain a significant scalar charge, the resulting attractive finite-range scalar force has implications for both the inspiral and merger phases of binary systems. We first present an analysis of the inspiral dynamics in Newtonian limit, and forecast the constraints on the mass of the scalar and charge of the compact objects for the Advanced LIGO gravitational wave observatory. We then perform a comparative study of binary neutron star mergers in general relativity with those of a one-parameter model of f (R ) gravity using fully relativistic hydrodynamical simulations. These simulations elucidate the effects of the scalar on the merger and postmerger dynamics. We comment on the utility of the full waveform (inspiral, merger, postmerger) to probe different regions of parameter space for both the particular model of f (R ) gravity studied here and for finite-range scalar forces more generally.

  4. Neutron activation analysis of reference materials by the k sub 0 standardization and relative methods

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, M C; Martinho, E [LNETI/ICEN, Sacavem (Portugal)

    1989-04-15

    Instrumental neutron activation analysis with the k{sub o}-standardization method was applied to eight geological, environmental and biological reference materials, including leaves, blood, fish, sediments, soils and limestone. To a first approximation, the results were normally distributed around the certified values with a standard deviation of 10%. Results obtained by using the relative method based on well characterized multi-element standards for IAEA CRM Soil-7 are reported.

  5. Determination of the relative power density distribution in a heterogeneous reactor from the results of measurements of the reactivity effects and the neutron importance function

    International Nuclear Information System (INIS)

    Bobrov, A. A.; Glushkov, E. S.; Zimin, A. A.; Kapitonova, A. V.; Kompaniets, G. V.; Nosov, V. I.; Petrushenko, R. P.; Smirnov, O. N.

    2012-01-01

    A method for experimental determination of the relative power density distribution in a heterogeneous reactor based on measurements of fuel reactivity effects and importance of neutrons from a californium source is proposed. The method was perfected on two critical assembly configurations at the NARCISS facility of the Kurchatov Institute, which simulated a small-size heterogeneous nuclear reactor. The neutron importance measurements were performed on subcritical and critical assemblies. It is shown that, along with traditionally used activation methods, the developed method can be applied to experimental studies of special features of the power density distribution in critical assemblies and reactors.

  6. Head-on collisions of binary white dwarf-neutron stars: Simulations in full general relativity

    International Nuclear Information System (INIS)

    Paschalidis, Vasileios; Etienne, Zachariah; Liu, Yuk Tung; Shapiro, Stuart L.

    2011-01-01

    We simulate head-on collisions from rest at large separation of binary white dwarf-neutron stars (WDNSs) in full general relativity. Our study serves as a prelude to our analysis of the circular binary WDNS problem. We focus on compact binaries whose total mass exceeds the maximum mass that a cold-degenerate star can support, and our goal is to determine the fate of such systems. A fully general relativistic hydrodynamic computation of a realistic WDNS head-on collision is prohibitive due to the large range of dynamical time scales and length scales involved. For this reason, we construct an equation of state (EOS) which captures the main physical features of neutron stars (NSs) while, at the same time, scales down the size of white dwarfs (WDs). We call these scaled-down WD models 'pseudo-WDs (pWDs)'. Using pWDs, we can study these systems via a sequence of simulations where the size of the pWD gradually increases toward the realistic case. We perform two sets of simulations; One set studies the effects of the NS mass on the final outcome, when the pWD is kept fixed. The other set studies the effect of the pWD compaction on the final outcome, when the pWD mass and the NS are kept fixed. All simulations show that after the collision, 14%-18% of the initial total rest mass escapes to infinity. All remnant masses still exceed the maximum rest mass that our cold EOS can support (1.92M · ), but no case leads to prompt collapse to a black hole. This outcome arises because the final configurations are hot. All cases settle into spherical, quasiequilibrium configurations consisting of a cold NS core surrounded by a hot mantle, resembling Thorne-Zytkow objects. Extrapolating our results to realistic WD compactions, we predict that the likely outcome of a head-on collision of a realistic, massive WDNS system will be the formation of a quasiequilibrium Thorne-Zytkow-like object.

  7. The performance of prototype position-sensitive neutron detectors on SXD at ISIS

    International Nuclear Information System (INIS)

    Wilson, C.C.

    1989-02-01

    The performance of two position-sensitive neutron detector designed for use on the single crystal diffractometer (SXD) at ISIS is assessed. The two detectors examined were the Anger camera 6 Li-glass scintillator PSD and a prototype fibre-optic encoded PSD based on 6 Li-doped ZnS plastic scintillator. The latter detector is found to be both simpler to fabricate and to produce better results on the evidence to date. A summary of some of the expected science from SXD and the performance of the detectors with respect to this is also given. (author)

  8. Cased Hole Evaluation Using Pulsed Neutron measurements and remedial actions on non-performing wells

    International Nuclear Information System (INIS)

    Mukerji, P.

    2002-01-01

    Advances in pulsed neutron spectroscopy tools have improved accuracy and precision of measured carbon-oxygen rations. The C/O ratios relate to the volumes of oil and water in the formation. Some of the improvements in accuracy and precision have resulted from better tool characterization in a wider variety of logging environments in the calibration facility and new spectral standards. The ability to combine advanced logging measurements has provided the operator with better diagnosis tools for identifying candidates for possible remedial actions. The successful diagnosis and treatment of water production problems requires the identification of specific influx zones. The information obtained from such logs allows effective treatment of unwanted wellbore fluid entries. This paper will present examples from logs run in the Niger delta. We will show how the application of pulsed neutron logs can optimise subsequent well intervention to reduce water production and/or increase oil production

  9. The new vertical neutron beam line at the CERN n-TOF facility design and outlook on the performance

    Energy Technology Data Exchange (ETDEWEB)

    Weiß, C., E-mail: christina.weiss@cern.ch [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Chiaveri, E.; Girod, S.; Vlachoudis, V.; Aberle, O. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Barros, S. [Instituto Tecnológico e Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, Lisboa (Portugal); Bergström, I. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Berthoumieux, E. [Commissariat à l’Énergie Atomique (CEA) Saclay – Irfu, Gif-sur-Yvette (France); Calviani, M. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Guerrero, C.; Sabaté-Gilarte, M. [Universidad de Sevilla (Spain); European Organization for Nuclear Research (CERN), Geneva (Switzerland); Tsinganis, A. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); National Technical University of Athens (NTUA) (Greece); Andrzejewski, J. [Uniwersytet Łódzki, Lodz (Poland); Audouin, L. [Centre National de la Recherche Scientifique/IN2P3 – IPN, Orsay (France); Bacak, M. [Atominstitut, Technische Universität Wien (Austria); Balibrea-Correa, J. [Centro de Investigaciones Energeticas Medioambientales y Tecnológicas (CIEMAT), Madrid (Spain); Barbagallo, M. [Istituto Nazionale di Fisica Nucleare, Bari (Italy); Bécares, V. [Centro de Investigaciones Energeticas Medioambientales y Tecnológicas (CIEMAT), Madrid (Spain); and others

    2015-11-01

    At the neutron time-of-flight facility n-TOF at CERN a new vertical beam line was constructed in 2014, in order to extend the experimental possibilities at this facility to an even wider range of challenging cross-section measurements of interest in astrophysics, nuclear technology and medical physics. The design of the beam line and the experimental hall was based on FLUKA Monte Carlo simulations, aiming at maximizing the neutron flux, reducing the beam halo and minimizing the background from neutrons interacting with the collimator or back-scattered in the beam dump. The present paper gives an overview on the design of the beam line and the relevant elements and provides an outlook on the expected performance regarding the neutron beam intensity, shape and energy resolution, as well as the neutron and photon backgrounds.

  10. The design of a multisource americium-beryllium (Am-Be) neutron irradiation facility using MCNP for the neutronic performance calculation.

    Science.gov (United States)

    Sogbadji, R B M; Abrefah, R G; Nyarko, B J B; Akaho, E H K; Odoi, H C; Attakorah-Birinkorang, S

    2014-08-01

    The americium-beryllium neutron irradiation facility at the National Nuclear Research Institute (NNRI), Ghana, was re-designed with four 20 Ci sources using Monte Carlo N-Particle (MCNP) code to investigate the maximum amount of flux that is produced by the combined sources. The results were compared with a single source Am-Be irradiation facility. The main objective was to enable us to harness the maximum amount of flux for the optimization of neutron activation analysis and to enable smaller sample sized samples to be irradiated. Using MCNP for the design construction and neutronic performance calculation, it was realized that the single-source Am-Be design produced a thermal neutron flux of (1.8±0.0007)×10(6) n/cm(2)s and the four-source Am-Be design produced a thermal neutron flux of (5.4±0.0007)×10(6) n/cm(2)s which is a factor of 3.5 fold increase compared to the single-source Am-Be design. The criticality effective, k(eff), of the single-source and the four-source Am-Be designs were found to be 0.00115±0.0008 and 0.00143±0.0008, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Neutron Research in HANARO

    International Nuclear Information System (INIS)

    Kim, Hark Rho

    2005-01-01

    monochromators, collimators, and precision motion units with its motion controller specific to heavy load neutron instruments, etc. The development and application of position sensitive detector (PSD) was a great success. In 2003, we started development of neutron mirror techniques and devices, which would be successfully utilized to develop neutron guides for the cold neutron research facility project. All of these efforts together make us enable to develop high performance neutron instruments and researches in cost-effective way. The project of constructing the cold neutron research facility (CNRF) at HANARO was re-initiated in July 2003. The first phase duration of CNRF project is five years, and the project envisions installation of cold neutron source, related systems, 3 neutron guides, and 6 cold neutron scattering instruments to satisfy the imminent needs of cold neutron beam. 6 neutron instruments include the relocation of 3 reactor hall instruments (8m-SANS, REF-V, REF-H) and the installation of 3 new instruments (40M-SANS, Cold-TAS, DC-TOF). The Ni guide manufacturing technology has been developed, and the super-mirror and the large area 2D detector are being developed. The design of the cold neutron laboratory building has been completed, of which safety analysis report has been submitted to the regulatory body, too

  12. Neutronic analysis of JET external neutron monitor response

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-01

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

  13. Octalithium plumbate as breeding blanket ceramic: Neutronic performances, synthesis and partial characterization

    International Nuclear Information System (INIS)

    Colominas, S.; Palermo, I.; Abellà, J.; Gómez-Ros, J.M.; Sanz, J.; Sedano, L.

    2012-01-01

    Highlights: ► Definition of a suitable configuration for the Li 8 PbO 6 breeding blanket design. ► Demonstration of the feasibility of Li 8 PbO 6 as a breeding material. ► Synthesis optimization in the Li 8 PbO 6 production. ► Characterization of Li 8 PbO 6 by X-ray phase analysis is discussed. - Abstract: A neutronic assessment of the performances of a helium-cooled Li 8 PbO 6 breeding blanket (BB) for the conceptual design of a DEMO fusion reactor is given. Different BB configurations have been considered in order to minimize the amount of beryllium required for neutron multiplication, including the use of graphite as reflector material. The calculated neutronic responses: tritium breeding ratio (TBR), power deposition in TF coils and power amplification factor, indicate the feasibility of Li 8 PbO 6 as breeding material. Furthermore, the synthesis and characterization of Li 8 PbO 6 by X-ray phase analysis are also discussed.

  14. Speciation analysis of cobalt in foods by high-performance liquid chromatography and neutron activation analysis

    International Nuclear Information System (INIS)

    Muto, Toshio; Koyama, Motoko

    1994-01-01

    A combined method by coupling high-performance liquid chromatography (HPLC, as a separation method) with neutron activation analysis (as a detection method) have been applied to the speciation analysis of cobalt in daily foods (e.g. egg, fish and milk). Cobalt species including free cobalt, vitamin B 12 and protein-bound cobalt were separated with a preparative HPLC and a centrifuge. Subsequently, the determination of cobalt in the separated species was made by neutron activation analysis. The results showed that the content of the total cobalt in the foods was found to lie in the range 0.4-11ng/g(0.4-11ppb) based on wet weight. The compositions of free cobalt, vitamin B 12 and protein-bound cobalt were ranged 16-43%, 55-73%, 2.3-17%, respectively. These experimental evidences suggest that the combination of HPLC and neutron activation analysis is expected to be a useful tool for speciation analysis of trace elements in biological as well as environmental materials. (author)

  15. FPGA hardware acceleration for high performance neutron transport computation based on agent methodology - 318

    International Nuclear Information System (INIS)

    Shanjie, Xiao; Tatjana, Jevremovic

    2010-01-01

    The accurate, detailed and 3D neutron transport analysis for Gen-IV reactors is still time-consuming regardless of advanced computational hardware available in developed countries. This paper introduces a new concept in addressing the computational time while persevering the detailed and accurate modeling; a specifically designed FPGA co-processor accelerates robust AGENT methodology for complex reactor geometries. For the first time this approach is applied to accelerate the neutronics analysis. The AGENT methodology solves neutron transport equation using the method of characteristics. The AGENT methodology performance was carefully analyzed before the hardware design based on the FPGA co-processor was adopted. The most time-consuming kernel part is then transplanted into the FPGA co-processor. The FPGA co-processor is designed with data flow-driven non von-Neumann architecture and has much higher efficiency than the conventional computer architecture. Details of the FPGA co-processor design are introduced and the design is benchmarked using two different examples. The advanced chip architecture helps the FPGA co-processor obtaining more than 20 times speed up with its working frequency much lower than the CPU frequency. (authors)

  16. Assessment of the Neutronic and Fuel Cycle Performance of the Transatomic Power Molten Salt Reactor Design

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Sean [Transatomic Power Corp., Cambridge, MA (United States); Dewan, Leslie [Transatomic Power Corp., Cambridge, MA (United States); Massie, Mark [Transatomic Power Corp., Cambridge, MA (United States); Davidson, Eva E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Betzler, Benjamin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Worrall, Andrew [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Powers, Jeffrey J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-09-01

    This report presents results from a collaboration between Transatomic Power Corporation (TAP) and Oak Ridge National Laboratory (ORNL) to provide neutronic and fuel cycle analysis of the TAP core design through the Department of Energy Gateway for Accelerated Innovation in Nuclear (GAIN) Nuclear Energy Voucher program. The TAP concept is a molten salt reactor using configurable zirconium hydride moderator rod assemblies to shift the neutron spectrum in the core from mostly epithermal at beginning of life to thermal at end of life. Additional developments in the ChemTriton modeling and simulation tool provide the critical moderator-to-fuel ratio searches and time-dependent parameters necessary to simulate the continuously changing physics in this complex system. The implementation of continuous-energy Monte Carlo transport and depletion tools in ChemTriton provide for full-core three-dimensional modeling and simulation. Results from simulations with these tools show agreement with TAP-calculated performance metrics for core lifetime, discharge burnup, and salt volume fraction, verifying the viability of reducing actinide waste production with this concept. Additional analyses of mass feed rates and enrichments, isotopic removals, tritium generation, core power distribution, core vessel helium generation, moderator rod heat deposition, and reactivity coeffcients provide additional information to make informed design decisions. This work demonstrates capabilities of ORNL modeling and simulation tools for neutronic and fuel cycle analysis of molten salt reactor concepts.

  17. Performance of the upgraded ultracold neutron source at Los Alamos National Laboratory and its implication for a possible neutron electric dipole moment experiment

    Science.gov (United States)

    Ito, T. M.; Adamek, E. R.; Callahan, N. B.; Choi, J. H.; Clayton, S. M.; Cude-Woods, C.; Currie, S.; Ding, X.; Fellers, D. E.; Geltenbort, P.; Lamoreaux, S. K.; Liu, C.-Y.; MacDonald, S.; Makela, M.; Morris, C. L.; Pattie, R. W.; Ramsey, J. C.; Salvat, D. J.; Saunders, A.; Sharapov, E. I.; Sjue, S.; Sprow, A. P.; Tang, Z.; Weaver, H. L.; Wei, W.; Young, A. R.

    2018-01-01

    The ultracold neutron (UCN) source at Los Alamos National Laboratory (LANL), which uses solid deuterium as the UCN converter and is driven by accelerator spallation neutrons, has been successfully operated for over 10 years, providing UCN to various experiments, as the first production UCN source based on the superthermal process. It has recently undergone a major upgrade. This paper describes the design and performance of the upgraded LANL UCN source. Measurements of the cold neutron spectrum and UCN density are presented and compared to Monte Carlo predictions. The source is shown to perform as modeled. The UCN density measured at the exit of the biological shield was 184 (32 ) UCN /cm3 , a fourfold increase from the highest previously reported. The polarized UCN density stored in an external chamber was measured to be 39 (7 ) UCN /cm3 , which is sufficient to perform an experiment to search for the nonzero neutron electric dipole moment with a one-standard-deviation sensitivity of σ (dn) =3 ×10-27e cm .

  18. Investigation of fuel lattice pitch changes influence on reactor performance through evaluate the neutronic parameters

    International Nuclear Information System (INIS)

    Zareian Ronizi, F.; Fadaei, A.H.; Setayeshi, S.; Shahidi, A.R.

    2015-01-01

    Highlights: • One of the most complex issues that Nu-engineers deal with is the design of NR core. • Numerous factors in nuclear core design depend on Fuel-to-Moderator volume ratio. • Aim of this research is to investigate RX performance for different lattice pitches. - Abstract: Nuclear reactor core design is one of the most complex issues that nuclear engineers deal with. The number and complexity of effective parameters and their impact on reactor design, which makes the problem difficult to solve, require precise knowledge of these parameters and their influence on the reactor operation. Numerous factors in a nuclear reactor core design depend on the Fuel-to-Moderator volume ratio, V F /V M , in a fuel cell. This ratio can be modified by changing the lattice pitch which is the thickness of water channels between fuels plates while keeping fuel slab dimensions fixed. Cooling and moderating properties of water are affected by such a change in a reactor core, and hence some parameters related to these properties might be changed. The aim of this research is to provide the suitable knowledge for nuclear core designing. To reach this goal, the first operating core of Tehran Research Reactor (TRR) with different lattice pitches is simulated, and the effect of different lattice pitches on some parameters such as effective multiplication factor (K eff ), reactor life time, distribution of neutron flux and power density in the core, as well as moderator temperature and density coefficient of reactivity are evaluated. The nuclear reactor analysis code, MTR-PC package is employed to carry out the considered calculation. Finally, the results are presented in some tables and graphs that provide useful information for nuclear engineers in the nuclear reactor core design

  19. Relating corporate social investment with financial performance

    OpenAIRE

    Kgabo L. Kobo; Collins C. Ngwakwe

    2017-01-01

    Previous researchers have found conflicting results between CSI and firm financial performance. This paper moves this debate further by examining the extent to which corporate social investment (CSI) relates with corporate financial performance (CFP) from a developing country perspective. The main aim of the paper was to determine the relationship between CSI, stock price, sales turnover and return on equity (ROE) amongst the socially responsible investing (SRI) companies in the Johannesburg ...

  20. Preliminary performance analysis of exponential experimental system for the determination of neutron effective multiplication factor of PWR spent fuel

    International Nuclear Information System (INIS)

    Shin, Heesung; Lee, Sang-Yun; Ro, Seung-Gy; Seo, Gi-Seok; Kim, Ho-Dong

    2002-01-01

    An exponential experiment system which is composed of neutron detector, signal analysis system and neutron source, 10 mCi Cf-252 has been installed in the storage pool of PIEF at KAERI in order to experimentally determining neutron effective multiplication factors of PWR spent fuel assemblies. Preliminary functional characteristic tests of the experimental system are performed for C15, J14 and J44 assemblies loaded in the pool. As a result of preliminary tests, the average neutron counts obtained for 3 minutes in the plateau of the C15, J14 and J44 assemblies are about 1900, 3800 and 3200, respectively. A dip of the neutron flux density distribution is noticed in the spacer grid position. Neutron counts at those positions appear to be reduced to about 70 % in comparison to the fuel position. The measured axial neutron distribution shapes are compared with the result for the P14 assembly and Cs-137 gamma scanning data performed in KAERI. It is revealed that the spacer grid position measured is consistent with the design specifications within a 2.3 % error. The exponential decay constants for the C15 assembly were determined to be 0.152 and 0.165 for detector and source scanning, respectively. (author)

  1. Enhancements and Health-Related Studies of Neutron Activation Analysis Technique

    International Nuclear Information System (INIS)

    Soliman, M.A.M.

    2012-01-01

    The work presented in this thesis covers two major points. One algorithm concerns with establishment of an accurate standardization method with multi-elemental capabilities and low workload suitable for NAA standardization at ETRR-2. The second one deals with constructing and developing an effective nondestructive technique for analysis of liquid samples based on NAA using (very) short-lived radionuclides. To achieve the first goal, attention has been directed toward implementation of the k 0 -method for calculation of the elements concentrations in the samples. The k 0 -method of NAA standardization has a considerable success as a method for accurate multi-elemental analysis with comparable low workload. The k 0 - method is based on the fact that the unknown sample is irradiated with only one standard element as comparator. To access the implementation of this method at ETRR-2, careful and complete characterization of the neutron flux parameters in the irradiation positions as well as the efficiency calibration of the γ-ray spectrometer must be carried out. The required neutron flux parameters are: the ratio of the thermal to epithermal neutron fluxes (f) and the deviation factor (α) of the epithermal neutron flux from the ideal 1/E law. The work presented in Chapter 4 shows the efficiency calibration curve of the γ ray spectrometer system which was obtained using standard radioactive point sources. Moreover, the f and α parameters were determined in some selected irradiation sites using sets of Zr-Au as neutron flux monitors. Due to different locations relative to the reactor core, the available neutron fluxes in the selected irradiation positions differ substantially, so that different irradiation demands can be satisfied. The reference materials coal NIST 1632c and IAEA-Soil 7 were analyzed for data validation and good agreement between the experimental values and the certified values was obtained. The obtained results have revealed that the k 0 -NAA

  2. Event-by-event simulation of single-neutron experiments to test uncertainty relations

    International Nuclear Information System (INIS)

    Raedt, H De; Michielsen, K

    2014-01-01

    Results from a discrete-event simulation of a recent single-neutron experiment that tests Ozawa's generalization of Heisenberg's uncertainty relation are presented. The event-based simulation algorithm reproduces the results of the quantum theoretical description of the experiment but does not require the knowledge of the solution of a wave equation, nor does it rely on detailed concepts of quantum theory. In particular, the data from these non-quantum simulations satisfy uncertainty relations derived in the context of quantum theory. (paper)

  3. The Design and Performance of the Spallation Neutron Source Low-Level RF Control System

    CERN Document Server

    Champion, M; Kasemir, K; Ma, H; Piller, C

    2004-01-01

    The Spallation Neutron Source linear accelerator low-level RF control system has been developed within a collaboration of Lawrence Berkeley, Los Alamos, and Oak Ridge national laboratories. Three distinct generations of the system, described in a previous publication [1], have been used to support beam commissioning at Oak Ridge. The third generation system went into production in early 2004, with installation in the coupled-cavity and superconducting linacs to span the remainder of the year. The final design of this system will be presented along with results of performance measurements.

  4. Experimental demonstration of H∞ filter performance for dynamic compensation of rhodium neutron detectors

    International Nuclear Information System (INIS)

    Park, Moon-Ghu; Choi, Yu-Sun; Lee, Kwang-Dae

    2008-01-01

    This paper describes the experimental demonstration of the theoretical result of the previous work on LMI (linear matrix inequality) based H ∞ filter for time-delay compensation of self-powered neutron detectors. The filter gains are optimized in the sense of noise attenuation level of H ∞ setting. By introducing bounded real lemma, the conventional algebraic Riccati inequalities are converted into linear matrix inequalities (LMIs). Finally, the filter design problem is solved via the convex optimization framework using LMIs. The experimental measurements of rhodium detector signal from a research reactor show that the predicted theoretical filter performance is verified by showing successful reconstruction of the reference power signal

  5. Performance test results of noninvasive characterization of RCRA surrogate waste by prompt gamma neutron activation analysis

    International Nuclear Information System (INIS)

    Gehrke, R.J.; Propp, W.A.

    1997-11-01

    A performance evaluation to determine the feasibility of using prompt gamma neutron activation analysis (PGNAA) for noninvasive, quantitative assay of mixed waste containers was sponsored by DOE's Office of Technology Development (OTD), the Mixed Waste Focus Area (MWFA), and the Idaho National Engineering and Environmental Laboratory (INEEL). The evaluation was conducted using a surrogate waste, based on Portland cement, that was spiked with three RCRA metals, mercury, cadmium, and lead. The results indicate that PGNAA has potential as a process monitor. However, further development is required to improve its sensitivity to meet regulatory requirements for determination of these RCRA metals

  6. Performance of the second Deep Inelastic Neutron Scatering spectrometer at the Bariloche electron LINAC

    International Nuclear Information System (INIS)

    Palomino, L A Rodríguez; Blostein, J J; Dawidowski, J

    2013-01-01

    We report on the new Deep Inelastic Neutron Scattering detector bank recently implemented at the Bariloche electron LINAC. We show the characterization and calibration process carried out, which comprises the determinarion of the detector bank efficiency, and the evaluation of the performance of the filter difference technique. As part of the benchmarking process, polyethylene spectra were measured and analyzed, and the scattering cross sections for carbon and hydrogen were determined in the process. With the addition of this new detector bank to the existing one, we evaluate the combined capacity of the two banks

  7. Cadmium-emitter self-powered thermal neutron detector performance characterization & reactor power tracking capability experiments performed in ZED-2

    Energy Technology Data Exchange (ETDEWEB)

    LaFontaine, M.W., E-mail: physics@execulink.com [LaFontaine Consulting, Kitchener, Ontario (Canada); Zeller, M.B. [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); Nielsen, K. [Royal Military College of Canada, SLOWPOKE-2 Reactor, Kingston, Ontario (Canada)

    2014-07-01

    Cadmium-emitter self-powered thermal neutron flux detectors (SPDs), are typically used for flux monitoring and control applications in low temperature, test reactors such as the SLOWPOKE-2. A collaborative program between Atomic Energy of Canada, academia (Royal Military College of Canada (RMCC)) and industry (LaFontaine Consulting) was initiated to characterize the incore performance of a typical Cd-emitter SPD; and to obtain a definitive measure of the capability of the detector to track changes in reactor power in real time. Prior to starting the experiment proper, Chalk River Laboratories' ZED-2 was operated at low power (5 watts nominal) to verify the predicted moderator critical height. Test measurements were then performed with the vertical center of the SPD emitter positioned at the vertical mid-plane of the ZED-2 reactor core. Measurements were taken with the SPD located at lattice position L0 (near center), and repeated at lattice position P0 (in D{sub 2}O reflector). An ionization chamber (part of the ZED-2 control instrumentation) monitored reactor power at a position located on the south side of the outside wall of the reactor's calandria. These experiments facilitated measurement of the absolute thermal neutron sensitivity of the subject Cd-emitter SPD, and validated the power tracking capability of said SPD. Procedural details of the experiments, data, calculations and associated graphs, are presented and discussed. (author)

  8. Performance Evaluation of the Neutron Coincidence Counter for the Advanced Spent Fuel Conditioning Process

    International Nuclear Information System (INIS)

    Lee, S.Y.; Li, T.K.; Menlove, Howard O.; Kim, H.D.; Ko, W.I.; Park, S.W.

    2005-01-01

    The Advanced Spent Fuel Conditioning Process (ACP) is a pyrochemical dry reprocessing technique to convert oxide-type spent nuclear fuel into a metallic form. The Korea Atomic Energy Research Institute (KAERI) has been developing this technology for the purpose of spent fuel management and is planning to perform a lab-scale demonstration in 2006. With this technology, a significant reduction of the volume and heat load of spent fuel is expected, which could decrease the burden of safety and economics. In this study, MCNPX code calculations were carried out to estimate the performance of a neutron coincidence counter designed for measruement of the process materials in the pilot-scale ACP facility. To verify the design requirement, the singles and doubles counting rates of the detectors were simulated with the latest coincidence capability of the MCNPX code. Then, the precision of the coincidence measurements were evaluated on various process materials from the ACP. It was verified that the performance of the neutron coincidence counter could meet the design criteria for all samples in the ACP, and the material accounting system for the pilot-scale ACP facility could meet the IAEA safeguards goals.

  9. Performance test of a gamma/neutron mapper on stored TRU waste durms at the RWMC

    International Nuclear Information System (INIS)

    Gehrke, R.J.; Josten, N.E.; Lawrence, R.S.

    1995-01-01

    The results from a performance test of a γ- and neutron-radiation measurement instrument used to provide two-dimensional radiation field maps are reported. The performance test was conducted at the Transuranic Storage Area of the Radioactive Waste Management Complex (RWMC) where interim storage is provided for 55-gal. drums of TRU waste from the Department of Energy's Rocky Flats Plant. The performance test consisted of scanning drums stacked five high and five wide to identify high radiation areas and possible discrepancies with the waste manifest. Scans were taken at standoff distances of 15 cm, 30 cm, 45 cm and 90 cm. Data were acquired at scan speeds of 7.5 cm/s and 15 cm/s. The results of these scans are presented as one, two and three dimensional contour plots of the radiation fields. A comparison of these results with manifests of these drums are compared and discussed. While the T-radiation fields as measured by the Health Physicist and by the radiation maps are in general in agreement, the TRU content as given in the manifest did not often correlate with the neutron map

  10. Business factors related to manufacturing firms' performance

    Directory of Open Access Journals (Sweden)

    Stergios Vranakis

    2014-01-01

    Full Text Available Purpose: The main goal is to understand the way many factors affect the investment decision making process and business performance. Design/methodology/approach: This study proposes a new conceptual framework for examining the reasons that manufacturing firms decide to invest on the acquisition of new machinery and equipment in order to improve their infrastructure. It incorporates various factors related to the internal business environment (quality management, investment decisions etc. Findings and Originality/value: A new conceptual framework, establishing the relations between many factors, has been developed, allowing the determinants of adoption of many implications to be discussed and to relate them to the peculiarities of the Greek manufacturing industry. Originality/value: This study presents an overview of the impact of machinery and equipment investment on firm’s performance, giving grasp for further research of the inter-organizational relationships that exist between them. 

  11. A neutronics study for improving the safety and performance parameters of a 3600 MWth Sodium-cooled Fast Reactor

    International Nuclear Information System (INIS)

    Sun, Kaichao; Krepel, Jiri; Mikityuk, Konstantin; Chawla, Rakesh

    2013-01-01

    , having almost no impact on the other considered parameters. A lower H/D ratio can also reduce void reactivity, but normally corresponds to worse neutron economy and, as such, leads to a less positive breeding gain and a smaller nominal reactivity margin. The Doppler constant, which is very sensitive to the neutron spectrum, can be significantly improved by the spectrum softening in the moderator pins case. Initial plutonium content effectively influences the nominal reactivity and breeding gain at the beginning-of-life, without significant changes of the safety related parameters. Finally, two different “synthesis core” concepts are proposed for further study, the common boundary condition set being to have a positive nominal reactivity margin at the end of equilibrium closed fuel cycle. Their considered safety and performance parameters at different fuel cycle states are presented in the end

  12. Performance of a tagged neutron inspection system (TNIS) based on portable sealed generators

    International Nuclear Information System (INIS)

    Nebbia, G.; Pesente, S.; Lunardon, M.; Viesti, G.; LeTourneur, P.; Heuveline, F.; Mangeard, M.; Tcheng, C.

    2004-01-01

    A portable sealed neutron generator has been modified to produce 14MeV tagged neutron beams with an embedded YAP:Ce scintillation detector. The system has been tested by detecting the coincident gamma-rays produced in the irradiation of a graphite sample by means of a standard NaI(Tl) scintillator. Time resolution of about δt=4-5ns (FWHM) has been measured. The sealed neutron tube has been operated up to 10 7 neutron/s. Possible applications in non-destructive assays and future developments of the Tagged Neutron Inspection System concept are discussed

  13. Mechanical performance optimization of neutron shielding material based on short carbon fiber reinforced B4C/epoxy resin

    International Nuclear Information System (INIS)

    Wang Peng; Tang Xiaobin; Chen Feida; Chen Da

    2013-01-01

    To satisfy engineering requirements for mechanics performance of neutron shielding material, short carbon fiber was used to reinforce the traditional containing B 4 C neutron shielding material and effects of fiber content, length and surface treatment to mechanics performance of material was discussed. Based on Americium-Beryllium neutron source, material's neutron shielding performance was tested. The result of experiment prove that tensile strength of material which the quality ratio of resin and fiber is 5:1 is comparatively excellent for 10wt% B 4 C of carbon fiber reinforced epoxy resin. The tensile properties of material change little with the fiber length ranged from 3-10 mm The treatment of fiber surface with silane coupling agent KH-550 can increase the tensile properties of materials by 20% compared with the untreated of that. A result of shielding experiment that the novel neutron shielding material can satisfy the neutron shielding requirements can be obtained by comparing with B 4 C/polypropylene materials. The material has good mechanical properties and wide application prospect. (authors)

  14. Rapidly rotating neutron stars with a massive scalar field—structure and universal relations

    International Nuclear Information System (INIS)

    Doneva, Daniela D.; Yazadjiev, Stoytcho S.

    2016-01-01

    We construct rapidly rotating neutron star models in scalar-tensor theories with a massive scalar field. The fact that the scalar field has nonzero mass leads to very interesting results since the allowed range of values of the coupling parameters is significantly broadened. Deviations from pure general relativity can be very large for values of the parameters that are in agreement with the observations. We found that the rapid rotation can magnify the differences several times compared to the static case. The universal relations between the normalized moment of inertia and quadrupole moment are also investigated both for the slowly and rapidly rotating cases. The results show that these relations are still EOS independent up to a large extend and the deviations from pure general relativity can be large. This places the massive scalar-tensor theories amongst the few alternative theories of gravity that can be tested via the universal I -Love- Q relations.

  15. Rapidly rotating neutron stars with a massive scalar field—structure and universal relations

    Energy Technology Data Exchange (ETDEWEB)

    Doneva, Daniela D.; Yazadjiev, Stoytcho S., E-mail: daniela.doneva@uni-tuebingen.de, E-mail: yazad@phys.uni-sofia.bg [Theoretical Astrophysics, Eberhard Karls University of Tübingen, Tübingen 72076 (Germany)

    2016-11-01

    We construct rapidly rotating neutron star models in scalar-tensor theories with a massive scalar field. The fact that the scalar field has nonzero mass leads to very interesting results since the allowed range of values of the coupling parameters is significantly broadened. Deviations from pure general relativity can be very large for values of the parameters that are in agreement with the observations. We found that the rapid rotation can magnify the differences several times compared to the static case. The universal relations between the normalized moment of inertia and quadrupole moment are also investigated both for the slowly and rapidly rotating cases. The results show that these relations are still EOS independent up to a large extend and the deviations from pure general relativity can be large. This places the massive scalar-tensor theories amongst the few alternative theories of gravity that can be tested via the universal I -Love- Q relations.

  16. I-Love-Q relations for neutron stars in dynamical Chern Simons gravity

    Science.gov (United States)

    Gupta, Toral; Majumder, Barun; Yagi, Kent; Yunes, Nicolás

    2018-01-01

    Neutron stars are ideal to probe, not only nuclear physics, but also strong-field gravity. Approximate universal relations insensitive to the star’s internal structure exist among certain observables and are useful in testing general relativity, as they project out the uncertainties in the equation of state. One such set of universal relations between the moment of inertia (I), the tidal Love number and the quadrupole moment (Q) has been studied both in general relativity and in modified theories. In this paper, we study the relations in dynamical Chern–Simons gravity, a well-motivated, parity-violating effective field theory, extending previous work in various ways. First, we study how projected constraints on the theory using the I-Love relation depend on the measurement accuracy of I with radio observations and that of the Love number with gravitational-wave observations. Provided these quantities can be measured with future observations, we find that the latter could place bounds on dynamical Chern–Simons gravity that are six orders of magnitude stronger than current bounds. Second, we study the I–Q and Q-Love relations in this theory by constructing slowly-rotating neutron star solutions to quadratic order in spin. We find that the approximate universality continues to hold in dynamical Chern–Simons gravity, and in fact, it becomes stronger than in general relativity, although its existence depends on the normalization of the dimensional coupling constant of the theory. Finally, we study the variation of the eccentricity of isodensity contours inside a star and its relation to the degree of universality. We find that, in most cases, the eccentricity variation is smaller in dynamical Chern–Simons gravity than in general relativity, providing further support to the idea that the approximate self-similarity of isodensity contours is responsible for universality.

  17. Neutronic and Thermal-hydraulic Modelling of High Performance Light Water Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Seppaelae, Malla [VTT Technical Research Centre of Finland, P.O.Box 1000, FI02044 VTT (Finland)

    2008-07-01

    High Performance Light Water Reactor (HPLWR), which is studied in EU project 'HPLWR2', uses water at supercritical pressures as coolant and moderator to achieve higher core outlet temperature and thus higher efficiency compared to present reactors. At VTT Technical Research Centre of Finland, functionality of the thermal-hydraulics in the coupled reactor dynamics code TRAB3D/ SMABRE was extended to supercritical pressures for the analyses of HPLWR. Input models for neutronics and thermal-hydraulics were made for TRAB3D/ SMABRE according to the latest HPLWR design. A preliminary analysis was performed in which the capability of SMABRE in the transition from supercritical pressures to subcritical pressures was demonstrated. Parameterized two-group cross sections for TRAB3D neutronics were received from Hungarian Academy of Sciences KFKI Atomic Energy Research Institute together with a subroutine for handling them. PSG, a new Monte Carlo transport code developed at VTT, was also used to generate two-group constants for HPLWR and comparisons were made with the KFKI cross sections and MCNP calculations. (author)

  18. Baseline drift effect on the performance of neutron and γ ray discrimination using frequency gradient analysis

    International Nuclear Information System (INIS)

    Liu Guofu; Luo Xiaoliang; Yang Jun; Lin Cunbao; Hu Qingqing; Peng Jinxian

    2013-01-01

    Frequency gradient analysis (FGA) effectively discriminates neutrons and γ rays by examining the frequency-domain features of the photomultiplier tube anode signal. This approach is insensitive to noise but is inevitably affected by the baseline drift similar to other pulse shape discrimination methods. The baseline drift effect is attributed to factors such as power line fluctuation, dark current, noise disturbances, hum, and pulse tail in front-end electronics. This effect needs to be elucidated and quantified before the baseline shift can be estimated and removed from the captured signal. Therefore, the effect of baseline shift on the discrimination performance of neutrons and γ rays with organic scintillation detectors using FGA is investigated in this paper. The relationship between the baseline shift and discrimination parameters of FGA is derived and verified by an experimental system consisting of an americium—beryllium source, a BC501A liquid scintillator detector, and a 5 GSample/s 8-bit oscilloscope. The theoretical and experimental results both show that the estimation of the baseline shift is necessary, and the removal of baseline drift from the pulse shapes can improve the discrimination performance of FGA. (authors)

  19. Neutronic and Thermal-hydraulic Modelling of High Performance Light Water Reactor

    International Nuclear Information System (INIS)

    Seppaelae, Malla

    2008-01-01

    High Performance Light Water Reactor (HPLWR), which is studied in EU project 'HPLWR2', uses water at supercritical pressures as coolant and moderator to achieve higher core outlet temperature and thus higher efficiency compared to present reactors. At VTT Technical Research Centre of Finland, functionality of the thermal-hydraulics in the coupled reactor dynamics code TRAB3D/ SMABRE was extended to supercritical pressures for the analyses of HPLWR. Input models for neutronics and thermal-hydraulics were made for TRAB3D/ SMABRE according to the latest HPLWR design. A preliminary analysis was performed in which the capability of SMABRE in the transition from supercritical pressures to subcritical pressures was demonstrated. Parameterized two-group cross sections for TRAB3D neutronics were received from Hungarian Academy of Sciences KFKI Atomic Energy Research Institute together with a subroutine for handling them. PSG, a new Monte Carlo transport code developed at VTT, was also used to generate two-group constants for HPLWR and comparisons were made with the KFKI cross sections and MCNP calculations. (author)

  20. The TOFOR Neutron Spectrometer For High-Performance Measurements of D Plasma Fuel Ion Properties

    International Nuclear Information System (INIS)

    Johnson, M. Gatu; Giacomelli, L.; Hjalmarsson, A.; Weiszflog, M.; Sunden, E. Andersson; Conroy, S.; Ericsson, G.; Hellesen, C.; Ronchi, E.; Sjoestrand, H.; Kaellne, J.; Gorini, G.; Tardocch, M.

    2008-01-01

    The impact of scattered neutrons on the total flux reaching the TOFOR spectrometer at JET has been studied to allow for improvement of the data analysis. The scattered neutrons are demonstrated to contribute significantly to the flux. This will have implications for any neutron diagnostic on ITER

  1. Calculation of thermal neutron self-shielding correction factors for aqueous bulk sample prompt gamma neutron activation analysis using the MCNP code

    International Nuclear Information System (INIS)

    Nasrabadi, M.N.; Jalali, M.; Mohammadi, A.

    2007-01-01

    In this work thermal neutron self-shielding in aqueous bulk samples containing neutron absorbing materials is studied using bulk sample prompt gamma neutron activation analysis (BSPGNAA) with the MCNP code. The code was used to perform three dimensional simulations of a neutron source, neutron detector and sample of various material compositions. The MCNP model was validated against experimental measurements of the neutron flux performed using a BF 3 detector. Simulations were performed to predict thermal neutron self-shielding in aqueous bulk samples containing neutron absorbing solutes. In practice, the MCNP calculations are combined with experimental measurements of the relative thermal neutron flux over the sample's surface, with respect to a reference water sample, to derive the thermal neutron self-shielding within the sample. The proposed methodology can be used for the determination of the elemental concentration of unknown aqueous samples by BSPGNAA where knowledge of the average thermal neutron flux within the sample volume is required

  2. Neutronics of pulsed spallation neutron sources

    CERN Document Server

    Watanabe, N

    2003-01-01

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

  3. A contribution to the development of the modular neutron detector (DEMON): performance evaluation through measurements and simulations; Contribution a la realisation du detecteur modulaire de neutrons (DEMON): etudes des performances par mesures et simulations

    Energy Technology Data Exchange (ETDEWEB)

    Mouatassim, S

    1994-07-01

    The modular neutron detector is dedicated to the study of heavy ion reaction mechanisms. Monte Carlo simulations are performed for the optimization of the NE213 scintillator cell size and the general geometrical setup for the DEMON multidetector of neutrons with a minimum of cross-talk. Tests are performed with various types of photomultiplier tubes and scintillators. Using high energy neutron beams, more than six different reaction processes were identified with pulse shape discrimination by the charge comparison method. Cross sections were estimated. Light yields of charged particles p, d, t and alpha in the NE213 organic scintillator were analyzed using different theoretical approaches, and the intrinsic efficiency of the DEMON`s modules was measured and compared to Monte Carlo calculations. The DEMON experimental filter was simulated and has been associated with the Gemini physical events generator to study the performance of such a multidetector. Thus, the DEMON response for neutron evaporation of excited nuclei and its influence on energy measurement and temperature determination were studied. The same filter was used to simulate pre- and post-fission emission of neutrons for the fission process of the composite {sup 126}Ba system formed in the {sup 19}F + {sup 107}Ag entrance channel. (from author) 70 figs., 99 refs.

  4. Performance of a reflectometer at continuous wave and pulsed neutron sources

    International Nuclear Information System (INIS)

    Fitzsimmons, M.R.

    1995-01-01

    The Monte-Carlo simulations presented here involve simulations of reflectivity measurements of one sample using a reflectometer of traditional geometry at different neutron sources. The same reflectometer was used in all simulations. Only the characteristics of the neutron source, and the technique used to measure neutron wavelength were changed. In the case of the CW simulation, a monochromating crystal was used to select a nearly monochromatic beam (MB) from the neutron spectrum. In the simulations of the pulse sources, the time needed to traverse a fixed distance was measured, from which neutron wavelength is deduced

  5. Some reciprocity-like relations in multi-group neutron diffusion and transport theory over bare homogeneous regions

    International Nuclear Information System (INIS)

    Modak, R.S.; Sahni, D.C.

    1996-01-01

    Some simple reciprocity-like relations that exist in multi-group neutron diffusion and transport theory over bare homogeneous regions are presented. These relations do not involve the adjoint solutions and are directly related to numerical schemes based on an explicit evaluation of the fission matrix. (author)

  6. Neutron optical potential of 28Si derived from the dispersion relation

    International Nuclear Information System (INIS)

    Kitazawa, H.; Igarasi, S.; Katsuragi, D.; Harima, Y.

    1992-01-01

    Based upon the dispersion theory, an optical potential of 28 Si was determined at the neutron energies from the Fermi energy to 20 MeV. In particular, discussion was given on a characteristic behavior of the optical potential for low-energy neutrons. Moreover, the validity of the dispersion theory was investigated for neutron single-particle bound states in 29 Si. (orig.)

  7. Merger of binary neutron stars of unequal mass in full general relativity

    International Nuclear Information System (INIS)

    Shibata, Masaru; Taniguchi, Keisuke; Uryu-bar, Ko-barji

    2003-01-01

    We present results of three dimensional numerical simulations of the merger of unequal-mass binary neutron stars in full general relativity. A Γ-law equation of state P=(Γ-1)ρε is adopted, where P, ρ, ε, and Γ are the pressure, rest mass density, specific internal energy, and the adiabatic constant, respectively. We take Γ=2 and the baryon rest-mass ratio Q M to be in the range 0.85-1. The typical grid size is (633,633,317) for (x,y,z). We improve several implementations since the latest work. In the present code, the radiation reaction of gravitational waves is taken into account with a good accuracy. This fact enables us to follow the coalescence all the way from the late inspiral phase through the merger phase for which the transition is triggered by the radiation reaction. It is found that if the total rest mass of the system is more than ∼1.7 times of the maximum allowed rest mass of spherical neutron stars, a black hole is formed after the merger, irrespective of the mass ratios. The gravitational waveforms and outcomes in the merger of unequal-mass binaries are compared with those in equal-mass binaries. It is found that the disk mass around the so formed black holes increases with decreasing rest-mass ratios and decreases with increasing compactness of neutron stars. The merger process and the gravitational waveforms also depend strongly on the rest-mass ratios even for the range Q M =0.85-1

  8. Testing universal relations of neutron stars with a nonlinear matter-gravity coupling theory

    International Nuclear Information System (INIS)

    Sham, Y.-H.; Lin, L.-M.; Leung, P. T.

    2014-01-01

    Due to our ignorance of the equation of state (EOS) beyond nuclear density, there is still no unique theoretical model for neutron stars (NSs). It is therefore surprising that universal EOS-independent relations connecting different physical quantities of NSs can exist. Lau et al. found that the frequency of the f-mode oscillation, the mass, and the moment of inertia are connected by universal relations. More recently, Yagi and Yunes discovered the I-Love-Q universal relations among the mass, the moment of inertia, the Love number, and the quadrupole moment. In this paper, we study these universal relations in the Eddington-inspired Born-Infeld (EiBI) gravity. This theory differs from general relativity (GR) significantly only at high densities due to the nonlinear coupling between matter and gravity. It thus provides us an ideal case to test how robust the universal relations of NSs are with respect to the change of the gravity theory. Due to the apparent EOS formulation of EiBI gravity developed recently by Delsate and Steinhoff, we are able to study the universal relations in EiBI gravity using the same techniques as those in GR. We find that the universal relations in EiBI gravity are essentially the same as those in GR. Our work shows that, within the currently viable coupling constant, there exists at least one modified gravity theory that is indistinguishable from GR in view of the unexpected universal relations.

  9. Testing Universal Relations of Neutron Stars with a Nonlinear Matter-Gravity Coupling Theory

    Science.gov (United States)

    Sham, Y.-H.; Lin, L.-M.; Leung, P. T.

    2014-02-01

    Due to our ignorance of the equation of state (EOS) beyond nuclear density, there is still no unique theoretical model for neutron stars (NSs). It is therefore surprising that universal EOS-independent relations connecting different physical quantities of NSs can exist. Lau et al. found that the frequency of the f-mode oscillation, the mass, and the moment of inertia are connected by universal relations. More recently, Yagi and Yunes discovered the I-Love-Q universal relations among the mass, the moment of inertia, the Love number, and the quadrupole moment. In this paper, we study these universal relations in the Eddington-inspired Born-Infeld (EiBI) gravity. This theory differs from general relativity (GR) significantly only at high densities due to the nonlinear coupling between matter and gravity. It thus provides us an ideal case to test how robust the universal relations of NSs are with respect to the change of the gravity theory. Due to the apparent EOS formulation of EiBI gravity developed recently by Delsate and Steinhoff, we are able to study the universal relations in EiBI gravity using the same techniques as those in GR. We find that the universal relations in EiBI gravity are essentially the same as those in GR. Our work shows that, within the currently viable coupling constant, there exists at least one modified gravity theory that is indistinguishable from GR in view of the unexpected universal relations.

  10. A contribution to the development of the modular neutron detector (DEMON): performance evaluation through measurements and simulations

    International Nuclear Information System (INIS)

    Mouatassim, S.

    1994-07-01

    The modular neutron detector is dedicated to the study of heavy ion reaction mechanisms. Monte Carlo simulations are performed for the optimization of the NE213 scintillator cell size and the general geometrical setup for the DEMON multidetector of neutrons with a minimum of cross-talk. Tests are performed with various types of photomultiplier tubes and scintillators. Using high energy neutron beams, more than six different reaction processes were identified with pulse shape discrimination by the charge comparison method. Cross sections were estimated. Light yields of charged particles p, d, t and alpha in the NE213 organic scintillator were analyzed using different theoretical approaches, and the intrinsic efficiency of the DEMON's modules was measured and compared to Monte Carlo calculations. The DEMON experimental filter was simulated and has been associated with the Gemini physical events generator to study the performance of such a multidetector. Thus, the DEMON response for neutron evaporation of excited nuclei and its influence on energy measurement and temperature determination were studied. The same filter was used to simulate pre- and post-fission emission of neutrons for the fission process of the composite 126 Ba system formed in the 19 F + 107 Ag entrance channel. (from author) 70 figs., 99 refs

  11. Determination of the decay constants and relative abundances of delayed neutrons by noise analysis in zero-power reactors

    International Nuclear Information System (INIS)

    Diniz, Ricardo

    2005-01-01

    A reactor noise approach has been employed at the IPEN/MB-01 research reactor facility in order to determine experimentally the effective delayed neutron parameters β i and λ i in a six group model and assuming the point reactor. The method can be considered a novice one because exploits the very low frequency domain of the spectral densities. The proposed method has some advantages to other in-pile methods since it does not disturb the reactor system and consequently does not 'excite' any sort of harmonic modes. As a byproduct and a consistency check, the β eff parameter was obtained without the need of the Diven factor and the power normalization and it is in excellent agreement with independent measurements. The theory/experiment comparison shows that for the abundances the JENDL 3.3 presents the best performance while for the decay constants the revised version of ENDF/B-VI.8 shows the best agreement. The best performance for the β eff determination is obtained with JENDL3.3. In contrast, ENDF/B-VI.8 and its revised version performed at LANL overestimate β eff by as much as 4%. The β eff results of this work support totally the proposal of reducing the thermal delayed neutron number for 235 U fission as made by Sakurai and Okajima. A new observed effect related to the correlation between the fluctuations of both measurement channels is also presented and discussed. This effect can be considered as an indirect evidence for the use of the point reactor model in this work as well as a possible useful tool in the understanding of reactor dynamics. (author)

  12. Performance of a neutron transport code with full phase space decomposition on the Cray Research T3D

    International Nuclear Information System (INIS)

    Dorr, M.R.; Salo, E.M.

    1995-01-01

    We present performance results obtained on a 128-node Cray Research T3D computer by a neutron transport code implementing a standard mtiltigroup, discrete ordinates algorithm on a three-dimensional Cartesian grid. After summarizing the implementation strategy used to obtain a full decomposition of phase space (i.e., simultaneous parallelization of the neutron energy, directional and spatial variables), we investigate the scalability of the fundamental source iteration step with respect to each phase space variable. We also describe enhancements that have enabled performance rates approaching 10 gigaflops on the full 128-node machine

  13. Studies performed on neutron-irradiated copper-doped iron specimens by means of neutron small-angle scattering

    International Nuclear Information System (INIS)

    Naraghi, M.

    1978-01-01

    By means of neutron small-angle scattering precipitation arising from heat-treatment and reactor irradiation in copper-alloyed iron specimens were studied. Copper content varried between 0 and 1.5%, irradiation temperature between 310 and 563K. The specimens had been cooled from the melt partly fast, partly slowely. By taking account of magnetic scattering and by investigating the azimuthal dependence of the total scattering it became possible to distinguish between copper precipitations and vacancy agglomerates. The most obvious effect in the slowly cooled specimens after irradiation with 2-10 19 fast neutrons per cm 2 at a temperature of 563 K is the existence of copper agglomerates with diameters of the order of magnitude of 5nm. Precipitation already occurs to a much lesser extent by the influence of temperature alone. Fast cooling from the melt or low irradiation temperature reduce precipitation during reactor irradiation. Moreover, there are indications on the formation of vacancy accumulations and dislocation rings, the latter especially in the fast cooled specimens. (orig.) [de

  14. Neutron beam applications

    International Nuclear Information System (INIS)

    Lee, Chang Hee; Lee, J. S.; Seong, B. S.

    2000-05-01

    For the materials science by neutron technique, the development of the various complementary neutron beam facilities at horizontal beam port of HANARO and the techniques for measurement and analysis has been performed. High resolution powder diffractometer, after the installation and performance test, has been opened and used actively for crystal structure analysis, magnetic structure analysis, phase transition study, etc., since January 1998. The main components for four circle diffractometer were developed and, after performance test, it has been opened for crystal structure analysis and texture measurement since the end of 1999. For the small angle neutron spectrometer, the main component development and test, beam characterization, and the preliminary experiment for the structure study of polymer have been carried out. Neutron radiography facility, after the precise performance test, has been used for the non-destructive test of industrial component. Addition to the development of main instruments, for the effective utilization of those facilities, the scattering techniques relating to quantitative phase analysis, magnetic structure analysis, texture measurement, residual stress measurement, polymer study, etc, were developed. For the neutron radiography, photographing and printing technique on direct and indirect method was stabilized and the development for the real time image processing technique by neutron TV was carried out. The sample environment facilities for low and high temperature, magnetic field were also developed

  15. GPU-based high performance Monte Carlo simulation in neutron transport

    Energy Technology Data Exchange (ETDEWEB)

    Heimlich, Adino; Mol, Antonio C.A.; Pereira, Claudio M.N.A. [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. de Inteligencia Artificial Aplicada], e-mail: cmnap@ien.gov.br

    2009-07-01

    Graphics Processing Units (GPU) are high performance co-processors intended, originally, to improve the use and quality of computer graphics applications. Since researchers and practitioners realized the potential of using GPU for general purpose, their application has been extended to other fields out of computer graphics scope. The main objective of this work is to evaluate the impact of using GPU in neutron transport simulation by Monte Carlo method. To accomplish that, GPU- and CPU-based (single and multicore) approaches were developed and applied to a simple, but time-consuming problem. Comparisons demonstrated that the GPU-based approach is about 15 times faster than a parallel 8-core CPU-based approach also developed in this work. (author)

  16. GPU-based high performance Monte Carlo simulation in neutron transport

    International Nuclear Information System (INIS)

    Heimlich, Adino; Mol, Antonio C.A.; Pereira, Claudio M.N.A.

    2009-01-01

    Graphics Processing Units (GPU) are high performance co-processors intended, originally, to improve the use and quality of computer graphics applications. Since researchers and practitioners realized the potential of using GPU for general purpose, their application has been extended to other fields out of computer graphics scope. The main objective of this work is to evaluate the impact of using GPU in neutron transport simulation by Monte Carlo method. To accomplish that, GPU- and CPU-based (single and multicore) approaches were developed and applied to a simple, but time-consuming problem. Comparisons demonstrated that the GPU-based approach is about 15 times faster than a parallel 8-core CPU-based approach also developed in this work. (author)

  17. Neutron activation analysis of bird bowls and related archaic ceramics from Miletus

    International Nuclear Information System (INIS)

    Kerschner, M.; Mommsen, H.; Beier, T.; Heimermann, D.; Hein, A.

    1993-01-01

    In this paper we present the results of a chemical investigation by neutron activation analysis of sherds of different kinds of bird kotylai, bird bowls and related wares excavated in Kalabaktepe, a hill of the ancient city of Miletus. A new archaeological classification of this well-known group of Archaic ceramics of eastern Greece is presented. A number of kiln wasters of misfired vessels from Kalabaktepe revealed a characteristic local pattern. This pattern helped to clarify the provenance of some of the bird bowls classified archaeologically as of orientalizing type: they have been made in Miletus. But bird kotylai and bird bowls in the ''standard fabric'' as well as other archaeologically related vessels show a different chemical pattern of unknown provenance. (author)

  18. Neutron activation analysis of bird bowls and related archaic ceramics from Miletus

    International Nuclear Information System (INIS)

    Kerschner, M.; Mommsen, H.; Beier, T.; Heimermann, D.; Hein, A.

    1993-01-01

    In this paper we present the results of a chemical investigation by neutron activation analysis of sherds of different kinds of bird kotylai, bird bowls and related wares excavated in Kalabaktepe, a hill of the ancient city of Miletus. A new archaeological classification of this well-known group of Archaic ceramics of eastern Greece is represented. A number of kiln wasters of misfired vessels from Kalabaktepe revealed a characteristic local pattern. This pattern helped to clarify the provenance of some of the bird bowls classified archaeologically as of orientalizing type: they have been made in Miletus. But bird kotylai and bird bowls in the 'standard fabric' as well as other archaeologically related vessels show a different chemical pattern of unknown provenance. (author)

  19. Results of the gamma-neutron mapper performance test on 55-gallon drums at the RWMC

    International Nuclear Information System (INIS)

    Gehrke, R.J.; Lawrence, R.S.; Roybal, L.G.; Svoboda, J.M.; Harker, D.J.; Thompson, D.N.; Carpenter, M.V.; Josten, N.E.

    1995-07-01

    The primary purpose of the gamma-neutron mapper (G at sign) is to provide accurate and quantitative spatial information of the gamma-ray and neutron radiation fields as a function of position about the excavation of a radioactive waste site. The GNM is designed to operate remotely and can be delivered to any point on an excavation by the robotic gantry crane developed by the dig-face project at the Idaho National Engineering Laboratory (INEL). It can also be easily adapted to other delivery systems. The GNM can be deployed over a waste site at a predetermined scan rate and has sufficient accuracy to identify and quantify radioactive contaminants of importance. The results reported herein are from a performance test conducted at the Transuranic Storage Area, Building 628, of the Radioactive Waste Management Complex located at the INEL. This building is an active interim-storage area for 55-gal drums of transuranic waste from the Department of Energy's Rocky Flats Plant. The performance test consisted of scanning a stack of drums five high by five wide. Prior to the test, radiation fields were measured by a health physicist at the center of the drums and ranged from 0.5 mR/h to 35 mR/h. Scans of the drums using the GNM were taken at standoff distances from the vertical drum stack of 15 cm, 30 cm, 45 cm, and 90 cm. Data were acquired at scan speeds of 7.5 cm/s and 15 cm/s. The results of these scans and a comparison of these results with the manifests of these drums are compared and discussed

  20. Performance assessment of new neutron cross section libraries using MCNP code and some critical benchmarks

    International Nuclear Information System (INIS)

    Bakkari, B El; Bardouni, T El.; Erradi, L.; Chakir, E.; Meroun, O.; Azahra, M.; Boukhal, H.; Khoukhi, T El.; Htet, A.

    2007-01-01

    Full text: New releases of nuclear data files made available during the few recent years. The reference MCNP5 code (1) for Monte Carlo calculations is usually distributed with only one standard nuclear data library for neutron interactions based on ENDF/B-VI. The main goal of this work is to process new neutron cross sections libraries in ACE continuous format for MCNP code based on the most recent data files recently made available for the scientific community : ENDF/B-VII.b2, ENDF/B-VI (release 8), JEFF3.0, JEFF-3.1, JENDL-3.3 and JEF2.2. In our data treatment, we used the modular NJOY system (release 99.9) (2) in conjunction with its most recent upadates. Assessment of the processed point wise cross sections libraries performances was made by means of some criticality prediction and analysis of other integral parameters for a set of reactor benchmarks. Almost all the analyzed benchmarks were taken from the international handbook of Evaluated criticality safety benchmarks experiments from OECD (3). Some revised benchmarks were taken from references (4,5). These benchmarks use Pu-239 or U-235 as the main fissionable materiel in different forms, different enrichments and cover various geometries. Monte Carlo calculations were performed in 3D with maximum details of benchmark description and the S(α,β) cross section treatment was adopted in all thermal cases. The resulting one standard deviation confidence interval for the eigenvalue is typically +/-13% to +/-20 pcm [fr

  1. Incidence of leukemia among atomic bomb survivors in relation to neutron and gamma dose, Hiroshima and Nagasaki, 1950-71

    International Nuclear Information System (INIS)

    Ishimaru, Toranosuke; Otake, Masanori; Ichimaru, Michito.

    1978-03-01

    The incidence of leukemia during 1950-71 in the fixed mortality sample of atomic bomb survivors in Hiroshima and Nagasaki has been analyzed as a function of individual gamma and neutron kerma and marrow dose. Two dose response models were tested for each of acute leukemia, chronic granulocytic leukemia, and all types of leukemia, respectively. Each model postulates that leukemia incidence depends upon the sum of the separate risks imposed by the gamma ray and neutron doses; in Model I both are assumed to be directly proportional to the respective doses, while Model II assumes that while the risk from neutrons is directly proportional to the dose, the risk from gamma rays is proportional to dose-squared. Weighted regression analyses were performed for each model. When the two models were fitted to the data for all types of leukemia, the estimated regression coefficients corresponding to the neutron and gamma ray doses both differed significantly from zero, for each model. However, when analysis was restricted to acute leukemia, both the neutron and gamma ray coefficients were significant only for Model II, and with respect to chronic granulocytic leukemia, only the coefficient of the neutron dose was significant, using either Model I or Model II. It appeared that the responses of the two leukemia types differed by type of radiation. If the chronic granulocytic and acute leukemias are considered together, the Model II appears to fit the data slightly better than Model I, but neither models is rejected by the data. (author)

  2. Neutronic performance of high-density LEU fuels in water-moderated and water-reflected research reactors

    International Nuclear Information System (INIS)

    Bretscher, M.M.; Matos, J.E.

    1996-01-01

    At the Reduced Enrichment for Research and Test Reactors (RERTR) meeting in September 1994, Durand reported that the maximum uranium loading attainable with U 3 Si 2 fuel is about 6.0 g U/cm 3 . The French Commissariat a l'Energie Atomique (CEA) plan to perform irradiation tests with 5 plates at this loading. Compagnie pour L'Etude et La Realisation de Combustibles Atomiques (CERCA) has also fabricated a few uranium nitride (UN) plates with a uranium density in the fuel meat of 7.0 g/cm 3 and found that UN is compatible with the aluminum matrix at temperatures below 500 C. High density dispersion fuels proposed for development include U-Zr(4 wt%)-Nb(2 wt%), U-Mo(5 wt%), and U-Mo(9 wt%). The purpose of this note is to examine the relative neutronic behavior of these high density fuels in a typical light water-reflected and water-moderated MTR-type research reactor. The results show that a dispersion of the U-Zr-Nb alloy has the most favorable neutronic properties and offers the potential for uranium densities greater than 8.0 g/cm 3 . On the other hand, UN is the least reactive fuel because of the relatively large 14 N(n,p) cross section. For a fixed value of k eff , the required 235 U loading per fuel element is least for the U-Zr-Nb fuel and steadily increases for the U-Mo(5%), U-Mo(9%), and UN fuels. Because of volume fraction limitations, the UO 2 dispersions are only useful for uranium densities below 5.0 g/cm 3 . In this density range, however, UO 2 is more reactive than U 3 Si 2

  3. Containment performance analyses for the Advanced Neutron Source Reactor at the Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Kim, S.H.; Taleyarkhan, R.P.; Georgevich, V.

    1992-10-01

    This paper discusses salient aspects of methodology, assumptions, and modeling of various features related to estimation of source terms from two conservatively scoped severe accident scenarios in the Advanced Neutron Source (ANS) reactor at the Oak Ridge National Laboratory. Various containment configurations are considered for steaming-pool-type accidents and an accident involving molten core-concrete interaction. Several design features (such as rupture disks) are examined to study containment response during postulated severe accidents. Also, thermal-hydraulic response of the containment and radionuclide transport and retention in the containment are studied. The results are described as transient variations of source terms for each scenario, which are to be used for studying off-site radiological consequences and health effects for these postulated severe accidents. Also highlighted will be a comparison of source terms estimated by two different versions of the MELCOR code

  4. Quantitative neutron radiography using neutron absorbing honeycomb

    International Nuclear Information System (INIS)

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

    1993-01-01

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

  5. Neutron detector

    Science.gov (United States)

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

    2011-04-05

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

  6. Bioremediation performance as related to chemical availability

    International Nuclear Information System (INIS)

    Loehr, R.; Olivera, F.; Webster, M.

    1995-01-01

    Two side-by-side field prepared bed land treatment units (PBLTU) were evaluated. One PBLTU (H unit) treated soils containing chemicals from a diesel spill that had occurred about 12 months earlier. The other PBLTU (G unit) treated soils containing crude oil that had been in the soil for many decades. Laboratory slurry treatability studies and indicated that the hydrocarbons in both soils could be bioremediated if adequate nutrients were provided. The PBLTU had nutrients applied periodically, and were operated in a manner consistent with good operational guidelines. PBLTU performance was based on reductions in mobility, toxicity, and chemical concentration. Spatially random soil samples were taken from the two field PBLTU monthly and analyzed for the above parameters as well as nutrients and pH. Periodically, microbial numbers and type in the soil samples also were evaluated. Performance was monitored over an 18 month period. In the H unit, no detectable TPH reductions occurred although petroleum hydrocarbon degrading microorganisms existed in the soil and other conditions were appropriate for bioremediation. GC/MS analyses indicated reduction in some specific hydrocarbons. The H unit soils had low chemical mobility as determined by leachability tests (TCLP, SPLP) and had low relative toxicity as determined by Microtox trademark

  7. The CERN n_TOF Facility: Neutron Beams Performances for Cross Section Measurements

    CERN Document Server

    Chiaveri, E; Andrzejewski, J; Audouin, L; Barbagallo, M; Bécares, V; Bečvář, F; Belloni, F; Berthoumieux, E; Billowes, J; Boccone, V; Bosnar, D; Brugger, M; Calviani, M; Calviño, F; Cano-Ott, D; Carrapiço, C; Cerutti, F; Chin, M; Colonna, N; Cortés, G; Cortés-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Duran, I; Dressler, R; Dzysiuk, N; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; García, A R; Giubrone, G; Gómez-Hornillos, M B; Gonçalves, I F; González-Romero, E; Griesmayer, E; Guerrero, C; Gunsing, F; Gurusamy, P; Hernández-Prieto, A; Jenkins, D G; Jericha, E; Kadi, Y; Käppeler, F; Karadimos, D; Kivel, N; Koehler, P; Kokkoris, M; Krtička, M; Kroll, J; Lampoudis, C; Langer, C; Leal-Cidoncha, E; Lederer, C; Leeb, H; Leong, L S; Losito, R; Mallick, A; Manousos, A; Marganiec, J; Martínez, T; Massimi, C; Mastinu, P F; Mastromarco, M; Meaze, M; Mendoza, E; Mengoni, A; Milazzo, P M; Mingrone, F; Mirea, M; Mondalaers, W; Paradela, C; Pavlik, A; Perkowski, J; Plompen, A; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Robles, M S; Roman, F; Rubbia, C; Sabaté-Gilarte, M; Sarmento, R; Saxena, A; Schillebeeckx, P; Schmidt, S; Schumann, D; Tagliente, G; Tain, J L; Tarrío, D; Tassan-Got, L; Tsinganis, A; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Versaci, R; Vermeulen, M J; Vlachoudis, V; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiss, C; Wright, T; Žugec, P

    2014-01-01

    This paper presents the characteristics of the existing CERN n\\_TOF neutron beam facility (n\\_TOF-EAR1 with a flight path of 185 meters) and the future one (n\\_TOF EAR-2 with a flight path of 19 meters), which will operate in parallel from Summer 2014. The new neutron beam will provide a 25 times higher neutron flux delivered in 10 times shorter neutron pulses, thus offering more powerful capabilities for measuring small mass, low cross section and/or high activity samples.

  8. Research on preparation and performance of graphite cement-based materials used for fast neutron shielding

    International Nuclear Information System (INIS)

    Xu Jun; Kang Qing; Shen Zhiqiang; Wang Zhenggang; Wang Zhiqiang

    2014-01-01

    Measurements have been carried out to investigate the 14.8 MeV neutron attenuation properties for 3 kinds of cement-graphite composites. In comparison with the void group, the 14.8 MeV neutron attenuation properties of cement-graphite composites raised not clearly in 8 mm thickness, and drop not remarkably in 40 mm thickness; with the increase of graphite content and the thickness, the 14.8 MeV neutron attenuation properties were enhanced clearly. The data may be useful to the radiation shielding design of neutron. (authors)

  9. Recent experience related to neutronic transients in Ontario Hydro CANDU nuclear generating stations

    International Nuclear Information System (INIS)

    Frescura, G.M.; Smith, A.J.; Lau, J.H.

    1991-01-01

    Ontario Hydro presently operates 18 CANDU reactors in the province of Ontario, Canada. All of these reactors are of the CANDU Pressurized Heavy Water design, although their design features differ somewhat reflecting the evolution that has taken place from 1971 when the first Pickering unit started operation to the present as the Darlington units are being placed in service. Over the last three years, two significant neutronic transients took place at the Pickering Nuclear Generating Station 'A' (NGS A) one of which resulted in a number of fuel failures. Both events provided valuable lessons in the areas of operational safety, fuel performance And accident analysis. The events and the lessons learned are discussed in this paper

  10. Evaluating the performance of two neutron spectrum unfolding codes based on iterative procedures and artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz-Rodriguez, J. M.; Reyes Alfaro, A.; Reyes Haro, A.; Solis Sanches, L. O.; Miranda, R. Castaneda; Cervantes Viramontes, J. M. [Universidad Autonoma de Zacatecas, Unidad Academica de Ingenieria Electrica. Av. Ramon Lopez Velarde 801. Col. Centro Zacatecas, Zac (Mexico); Vega-Carrillo, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Ingenieria Electrica. Av. Ramon Lopez Velarde 801. Col. Centro Zacatecas, Zac., Mexico. and Unidad Academica de Estudios Nucleares. C. Cip (Mexico)

    2013-07-03

    In this work the performance of two neutron spectrum unfolding codes based on iterative procedures and artificial neural networks is evaluated. The first one code based on traditional iterative procedures and called Neutron spectrometry and dosimetry from the Universidad Autonoma de Zacatecas (NSDUAZ) use the SPUNIT iterative algorithm and was designed to unfold neutron spectrum and calculate 15 dosimetric quantities and 7 IAEA survey meters. The main feature of this code is the automated selection of the initial guess spectrum trough a compendium of neutron spectrum compiled by the IAEA. The second one code known as Neutron spectrometry and dosimetry with artificial neural networks (NDSann) is a code designed using neural nets technology. The artificial intelligence approach of neural net does not solve mathematical equations. By using the knowledge stored at synaptic weights on a neural net properly trained, the code is capable to unfold neutron spectrum and to simultaneously calculate 15 dosimetric quantities, needing as entrance data, only the rate counts measured with a Bonner spheres system. Similarities of both NSDUAZ and NSDann codes are: they follow the same easy and intuitive user's philosophy and were designed in a graphical interface under the LabVIEW programming environment. Both codes unfold the neutron spectrum expressed in 60 energy bins, calculate 15 dosimetric quantities and generate a full report in HTML format. Differences of these codes are: NSDUAZ code was designed using classical iterative approaches and needs an initial guess spectrum in order to initiate the iterative procedure. In NSDUAZ, a programming routine was designed to calculate 7 IAEA instrument survey meters using the fluence-dose conversion coefficients. NSDann code use artificial neural networks for solving the ill-conditioned equation system of neutron spectrometry problem through synaptic weights of a properly trained neural network. Contrary to iterative procedures, in

  11. Evaluating the performance of two neutron spectrum unfolding codes based on iterative procedures and artificial neural networks

    Science.gov (United States)

    Ortiz-Rodríguez, J. M.; Reyes Alfaro, A.; Reyes Haro, A.; Solís Sánches, L. O.; Miranda, R. Castañeda; Cervantes Viramontes, J. M.; Vega-Carrillo, H. R.

    2013-07-01

    In this work the performance of two neutron spectrum unfolding codes based on iterative procedures and artificial neural networks is evaluated. The first one code based on traditional iterative procedures and called Neutron spectrometry and dosimetry from the Universidad Autonoma de Zacatecas (NSDUAZ) use the SPUNIT iterative algorithm and was designed to unfold neutron spectrum and calculate 15 dosimetric quantities and 7 IAEA survey meters. The main feature of this code is the automated selection of the initial guess spectrum trough a compendium of neutron spectrum compiled by the IAEA. The second one code known as Neutron spectrometry and dosimetry with artificial neural networks (NDSann) is a code designed using neural nets technology. The artificial intelligence approach of neural net does not solve mathematical equations. By using the knowledge stored at synaptic weights on a neural net properly trained, the code is capable to unfold neutron spectrum and to simultaneously calculate 15 dosimetric quantities, needing as entrance data, only the rate counts measured with a Bonner spheres system. Similarities of both NSDUAZ and NSDann codes are: they follow the same easy and intuitive user's philosophy and were designed in a graphical interface under the LabVIEW programming environment. Both codes unfold the neutron spectrum expressed in 60 energy bins, calculate 15 dosimetric quantities and generate a full report in HTML format. Differences of these codes are: NSDUAZ code was designed using classical iterative approaches and needs an initial guess spectrum in order to initiate the iterative procedure. In NSDUAZ, a programming routine was designed to calculate 7 IAEA instrument survey meters using the fluence-dose conversion coefficients. NSDann code use artificial neural networks for solving the ill-conditioned equation system of neutron spectrometry problem through synaptic weights of a properly trained neural network. Contrary to iterative procedures, in neural

  12. Evaluating the performance of two neutron spectrum unfolding codes based on iterative procedures and artificial neural networks

    International Nuclear Information System (INIS)

    Ortiz-Rodríguez, J. M.; Reyes Alfaro, A.; Reyes Haro, A.; Solís Sánches, L. O.; Miranda, R. Castañeda; Cervantes Viramontes, J. M.; Vega-Carrillo, H. R.

    2013-01-01

    In this work the performance of two neutron spectrum unfolding codes based on iterative procedures and artificial neural networks is evaluated. The first one code based on traditional iterative procedures and called Neutron spectrometry and dosimetry from the Universidad Autonoma de Zacatecas (NSDUAZ) use the SPUNIT iterative algorithm and was designed to unfold neutron spectrum and calculate 15 dosimetric quantities and 7 IAEA survey meters. The main feature of this code is the automated selection of the initial guess spectrum trough a compendium of neutron spectrum compiled by the IAEA. The second one code known as Neutron spectrometry and dosimetry with artificial neural networks (NDSann) is a code designed using neural nets technology. The artificial intelligence approach of neural net does not solve mathematical equations. By using the knowledge stored at synaptic weights on a neural net properly trained, the code is capable to unfold neutron spectrum and to simultaneously calculate 15 dosimetric quantities, needing as entrance data, only the rate counts measured with a Bonner spheres system. Similarities of both NSDUAZ and NSDann codes are: they follow the same easy and intuitive user's philosophy and were designed in a graphical interface under the LabVIEW programming environment. Both codes unfold the neutron spectrum expressed in 60 energy bins, calculate 15 dosimetric quantities and generate a full report in HTML format. Differences of these codes are: NSDUAZ code was designed using classical iterative approaches and needs an initial guess spectrum in order to initiate the iterative procedure. In NSDUAZ, a programming routine was designed to calculate 7 IAEA instrument survey meters using the fluence-dose conversion coefficients. NSDann code use artificial neural networks for solving the ill-conditioned equation system of neutron spectrometry problem through synaptic weights of a properly trained neural network. Contrary to iterative procedures, in neural

  13. Neutronic performance issues of the breeding blanket options for the European DEMO fusion power plant

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, U., E-mail: ulrich.fischer@kit.edu [Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Bachmann, C. [EUROfusion—Programme Management Unit, Boltzmannstr. 2, 85748 Garching (Germany); Jaboulay, J.-C. [CEA-Saclay, DEN, DM2S, SERMA, LPEC, 91191 Gif-sur-Yvette (France); Moro, F. [ENEA, Dipartimento Fusione e tecnologie per la Sicurezza Nucleare, Via E. Fermi 45, 00044 Frascati, Rome (Italy); Palermo, I. [Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid (Spain); Pereslavtsev, P. [Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Villari, R. [ENEA, Dipartimento Fusione e tecnologie per la Sicurezza Nucleare, Via E. Fermi 45, 00044 Frascati, Rome (Italy)

    2016-11-01

    Highlights: • Breeder blanket concepts for DEMO—design features. • Neutronic characteristics of breeder blankets. • Evaluation of Tritium breeding potential. • Evaluation of shielding performance. - Abstract: This paper presents nuclear performance issues of the HCPB, HCLL, DCLL and WCLL breeder blankets, which are under development within the PPPT (Power Plant Physics and Technology) programme of EUROfusion, with the objective to assess the potential and suitability of the blankets for the application to DEMO. The assessment is based on the initial design versions of the blankets developed in 2014. The Tritium breeding potential is considered sufficient for all breeder blankets although the initial design versions of the HCPB, HCLL and DCLL blankets were shown to require further design improvements. Suitable measures have been proposed and proven to be sufficient to achieve the required Tritium Breeding Ratio (TBR) ≥ 1.10. The shielding performance was shown to be sufficient to protect the super-conducting toroidal field coil provided that efficient shielding material mixtures including WC or borated water are utilized. The WCLL blanket does not require the use of such shielding materials due to a very compact blanket support structure/manifold configuration which yet requires design verification. The vacuum vessel can be safely operated over the full anticipated DEMO lifetime of 6 full power years for all blanket concepts considered.

  14. Neutron imaging methods for the investigation of energy related materials. Fuel cells, battery, hydrogen storage and nuclear fuel

    Science.gov (United States)

    Lehmann, Eberhard H.; Boillat, Pierre; Kaestner, Anders; Vontobel, Peter; Mannes, David

    2015-10-01

    After a short explanation of the state-of-the-art in the field of neutron imaging we give some examples how energy related materials can be studied successfully. These are in particular fuel cell studies, battery research approaches, the storage of hydrogen, but also some investigations with nuclear fuel components. The high contrast for light isotopes like H-1, Li-6 or B-10 are used to trace low amounts of material even within compact sealing of metals which are relatively transparent for neutrons at the same time.

  15. Effects of mixed neutron-γ total-body irradiation on physical activity performance of rhesus monkeys

    International Nuclear Information System (INIS)

    Franz, C.G.

    1985-01-01

    Behavioral incapacitation for a physical activity task and its relationship to emesis and survival time following exposure to ionizing radiation were evaluated in 39 male rhesus monkeys (Macaca mulatta). Subjects were trained to perform a shock avoidance activity task for 6 hr on a 10-min work/5-min rest schedule in a nonmotorized physical activity wheel. Following stabilization of performance, each subject received a single, pulsed dose of mixed neutron-γ, whole-body radiation (n/γ = 3.0) ranging between 1274 and 4862 rad. Performance testing was started 45 sec after exposure. A dose-response function for early transient incapacitation (ETI) during the first 2 hr after irradiation was fitted, and the median effective dose (ED 50 ) was calculated to be 1982 rad. Analysis done on the relationship of dose to ETI, emesis, and survival time found (a) a significant relationship between the radiation dose and the number and duration of ETIs; (b) no correlation between emesis and dose, survival time, or ETI; (c) no relation between survival time and ETI at any dose; and (d) no significant difference in survival time for dose groups between 1766 +/- 9 (SEM) and 2308 +/- 23 rad

  16. Relative performance of several inexpensive accelerometers

    Science.gov (United States)

    Evans, John R.; Rogers, John A.

    1995-01-01

    We examined the performance of several low-cost accelerometers for highly cost-driven applications in recording earthquake strong motion. We anticipate applications for such sensors in providing the lifeline and emergency-response communities with an immediate, comprehensive picture of the extent and characteristics of likely damage. We also foresee their use as 'filler' instruments sited between research-grade instruments to provide spatially detailed and near-field records of large earthquakes (on the order of 1000 stations at 600-m intervals in San Fernando Valley, population 1.2 million, for example). The latter applications would provide greatly improved attenuation relationships for building codes and design, the first examples of mainshock information (that is, potentially nonlinear regime) for microzonation, and a suite of records for structural engineers. We also foresee possible applications in monitoring structural inter-story drift during earthquakes, possibly leading to local and remote alarm functions as well as design criteria. This effort appears to be the first of its type at the USGS. It is spurred by rapid advances in sensor technology and the recognition of potential non-classical applications. In this report, we estimate sensor noise spectra, relative transfer functions and cross-axis sensitivity of six inexpensive sensors. We tested three micromachined ('silicon-chip') sensors in addition to classical force-balance and piezoelectric examples. This sample of devices is meant to be representative, not comprehensive. Sensor noise spectra were estimated by recording system output with the sensor mounted on a pneumatically supported 545-kg optical-bench isolation table. This isolation table appears to limit ground motion to below our system noise level. These noise estimates include noise introduced by signal-conditioning circuitry, the analog-to-digital converter (ADC), and noise induced in connecting wiring by ambient electromagnetic fields in

  17. Analysis of relation between the mutation frequencies and somatic recombination induced by neutrons and the age of D. Melanogaster larvae

    International Nuclear Information System (INIS)

    Guzman R, J.; Zambrano A, F.; Paredes G, L.; Delfin L, A.; Quiroz R, C.

    1998-01-01

    Neutrons are subatomic particles with neutral electric charge, equal zero, which are emitted during the fissile material fission in nuclear reactors. It is known a little about biological effects induced by neutrons. There is a world interest in the use of reactors and accelerators for patients radiotherapy using neutrons with the purpose to destroy malignant cells of deep tumours where traditional methods have not given satisfactory results. There for it is required to do wide studies of biological effects of neutrons as well as their dosimetry. It was used the Smart test (Somatic Mutation and Recombination Test) of D. Melanogaster for quantifying the mutation induction and somatic recombination induced by neutrons of the National Institute of Nuclear Research reactor, at power of 300 and 1000 k W, with equivalent doses calculated 95.14 and 190.2 Sv for 300 k W and of 25.64 and 51.29 Sv for 1000 k W, using larvae with 72 or 96 hours aged. It was observed a linear relation between equivalent dose and genetic effects frequency, these last were greater when the reactor power was 1000 k W than those 300 k W. It was observed too that the damage was greater in 96 hours larvae than those 72 hours. The stain size presented an inverse relation with respect to larvae age. It is concluded that the Smart system is sensitive to neutrons effect and it responds of a directly proportional form to radiation dose, as well as to dose rate. It is noted more the effect when are used larvas in pre pupa stage where the irradiation target (imagal cells) is greater. The Smart is sensitive to damage induced by neutrons , thus can be used to studying its direct biological effects or by the use of chemical modulators. (Author)

  18. Neutron source

    International Nuclear Information System (INIS)

    Cason, J.L. Jr.; Shaw, C.B.

    1975-01-01

    A neutron source which is particularly useful for neutron radiography consists of a vessel containing a moderating media of relatively low moderating ratio, a flux trap including a moderating media of relatively high moderating ratio at the center of the vessel, a shell of depleted uranium dioxide surrounding the moderating media of relatively high moderating ratio, a plurality of guide tubes each containing a movable source of neutrons surrounding the flux trap, a neutron shield surrounding one part of each guide tube, and at least one collimator extending from the flux trap to the exterior of the neutron source. The shell of depleted uranium dioxide has a window provided with depleted uranium dioxide shutters for each collimator. Reflectors are provided above and below the flux trap and on the guide tubes away from the flux trap

  19. EL2-related defects in neutron irradiated GaAs1/sub -x/P/sub x/ alloys

    International Nuclear Information System (INIS)

    Munoz, E.; Garcia, F.; Jimenez, B.; Calleja, E.; Gomez, A.; Alcober, V.

    1985-01-01

    The generation of EL2-related defects in GaAsP alloys by fast neutron irradiation has been studied through deep level transient spectroscopy and photocapacitance techniques. After irradiation p-n junctions were not annealed at high temperatures. In the composition range x>0.4, fast neutrons generate a broad center at E/sub c/-0.7 eV that it is suggested to belong to the EL2 family. The presence of photocapacitance quenching effects has been taken as a preliminary fingerprint to make the above assignment. From computer analysis of the nonexponential transient capacitance waveforms, evidence that neutron irradiation creates a family of midgap levels, EL2-related, is found

  20. Simulation of Neutron Backscattering applied to organic material detection

    International Nuclear Information System (INIS)

    Forero, N. C.; Cruz, A. H.; Cristancho, F.

    2007-01-01

    The Neutron Backscattering technique is tested when performing the task of localizing hydrogenated explosives hidden in soil. Detector system, landmine, soil and neutron source are simulated with Geant4 in order to obtain the number of neutrons detected when several parameters like mine composition, relative position mine-source and soil moisture are varied

  1. Preliminary study on zinc-carbon battery performance by using neutron tomography

    International Nuclear Information System (INIS)

    Abdul Aziz Mohamed; Nor Abidin Ashari; Mohd Zaid Abdullah; Junita Mohamad Saleh; Azraf Azman; Megat Harun AlRashid Megat Ahmad; Rafhayudi Jamro

    2008-08-01

    This paper describes on the discharging characteristic of zinc-carbon batteries (dry cells) by using a neutron imaging technique called a monochromatic neutron tomography. Experiment was conducted on the Nuclear Malaysia neutron tomography prototype instrument which based on 1-dimensional position sensitive neutron detector. The instrument is constructed at the small angle neutron scattering (SANS) beam line built at the one of the beam ports of TRIGA MARK II Research reactor, Malaysian Nuclear Agency, Bangi, Selangor. The main aim of this preliminary experiment was to test the instrument capability on a real industrial component. It was also aimed to understand structural and chemical changes of these battery particles after experiencing a discharging process. In this preliminary work, new and used batteries used were the products of Eveready company. (Author)

  2. The relative biological effectiveness of a high energy neutron beam for micronuclei induction in T-lymphocytes of different individuals

    Energy Technology Data Exchange (ETDEWEB)

    Slabbert, J.P., E-mail: jps@tlabs.ac.z [NRF iThemba LABS (Laboratory for Accelerated Based Sciences), Somerset West (South Africa); Dept. of Medical Imaging and Clinical Oncology, University of Stellenbosch (South Africa); August, L. [NRF iThemba LABS (Laboratory for Accelerated Based Sciences), Somerset West (South Africa); Vral, A. [Dept. of Basic Medical Sciences, Ghent University (Belgium); Symons, J. [NRF iThemba LABS (Laboratory for Accelerated Based Sciences), Somerset West (South Africa)

    2010-12-15

    In assessing the radiation risk of personnel exposed to cosmic radiation fields as it pertains to radiological damage during travel in civilian aircrafts, it is particularly important to know the relative biological effectiveness (RBE) for high energy neutrons. It has been the subject of numerous investigations in recent years using different neutron energies and cytogenetic examinations. Variations in the radiosensitivity of white blood cells for different individuals are likely to influence the estimate of the relative biological effectiveness for high energy neutrons. This as such observations have been noted in the response of different cancer cell lines with varying inherent sensitivities. In this work the radiosensitivities of T-lymphocytes of different individuals to the p(66)/Be neutron beam at iThemba LABS were measured using micronuclei formations and compared to that noted following exposure to {sup 60}Co {gamma}-rays. The principle objective of this investigation was to establish if a relationship between neutron RBE and variation in biological response to {sup 60}Co {gamma}-rays for lymphocytes from different individuals could be determined. Peripheral blood samples were collected from four healthy donors and isolated lymphocytes were exposed to different doses of {sup 60}Co {gamma}-rays (1-5 Gy) and p(66)/Be neutrons (0.5-2.5 Gy). One sample per donor was not exposed to radiation and served as a control. Lymphocytes were stimulated using PHA and cultured to induce micronuclei in cytokinesis-blocked cells. Micronuclei yields were numerated using fluorescent microscopy. Radiosensitivities and RBE values were calculated from the fitted parameters describing the micronuclei frequency dose response data. Dissimilar dose response curves for different donors were observed reflecting varying inherent sensitivities to both neutron and gamma radiation. A clear reduction in the dose limiting RBE{sub M} is noted for donors with lymphocytes more sensitive to

  3. Neutronic analyses of design issues affecting the tritium breeding performance in different DEMO blanket concepts

    Energy Technology Data Exchange (ETDEWEB)

    Pereslavtsev, Pavel, E-mail: pavel.pereslavtsev@kit.edu [Karlsruhe Institute for Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Bachmann, Christian [EUROfusion – Programme Management Unit, Boltzmannstrasse 2, 85748 Garching (Germany); Fischer, Ulrich [Karlsruhe Institute for Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2016-11-01

    Highlights: • Realistic 3D MCNP model based on the CAD engineering model of DEMO. • Automated procedure for the generation and arrangement of the blanket modules for different DEMO concepts: HCPB, HCLL, WCLL, DCLL. • Several parameters affecting tritium breeding ratio (TBR) were investigated. • A set of practical guidelines was prepared for the designers developing the individual breeding blanket concepts. - Abstract: Neutronic analyses were performed to assess systematically the tritium breeding ratio (TBR) variations in the DEMO for the different blanket concepts HCPB, HCLL, WCLL and DCLL DEMOs due to modifications of the blanket configurations. A dedicated automated procedure was developed to fill the breeding modules in the common generic model in correspondence to the different concepts. The TBR calculations were carried out using the MCNP5 Monte Carlo code. The following parameters affecting the global TBR were investigated: TBR poloidal distribution, radial breeder zone depth, {sup 6}Li enrichment, steel content in the breeder modules, poloidal segmentation of the breeder blanket volume, size of gaps between blankets, thickness of the first wall and of the tungsten armour. Based on the results a set of practical guidelines was prepared for the designers developing the individual breeding blanket concepts with the goal to achieve the required tritium breeding performance in DEMO.

  4. Neutronic analyses of design issues affecting the tritium breeding performance in different DEMO blanket concepts

    International Nuclear Information System (INIS)

    Pereslavtsev, Pavel; Bachmann, Christian; Fischer, Ulrich

    2016-01-01

    Highlights: • Realistic 3D MCNP model based on the CAD engineering model of DEMO. • Automated procedure for the generation and arrangement of the blanket modules for different DEMO concepts: HCPB, HCLL, WCLL, DCLL. • Several parameters affecting tritium breeding ratio (TBR) were investigated. • A set of practical guidelines was prepared for the designers developing the individual breeding blanket concepts. - Abstract: Neutronic analyses were performed to assess systematically the tritium breeding ratio (TBR) variations in the DEMO for the different blanket concepts HCPB, HCLL, WCLL and DCLL DEMOs due to modifications of the blanket configurations. A dedicated automated procedure was developed to fill the breeding modules in the common generic model in correspondence to the different concepts. The TBR calculations were carried out using the MCNP5 Monte Carlo code. The following parameters affecting the global TBR were investigated: TBR poloidal distribution, radial breeder zone depth, "6Li enrichment, steel content in the breeder modules, poloidal segmentation of the breeder blanket volume, size of gaps between blankets, thickness of the first wall and of the tungsten armour. Based on the results a set of practical guidelines was prepared for the designers developing the individual breeding blanket concepts with the goal to achieve the required tritium breeding performance in DEMO.

  5. Performance of Large Neutron Detectors Containing Lithium-Gadolinium-Borate Scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Slaughter, David M.; Stuart, Cory R.; Klaass, R. Fred; Merrill, David B. [MSI/Photogenics Division, Orem, Utah (United States)

    2015-07-01

    This paper describes the development and testing of a neutron counter, spectrometer, and dosimeter that is compact, efficient, and accurate. A self-contained neutron detection instrument has wide applications in health physics, scientific research, and programs to detect, monitor, and control strategic nuclear materials (SNM). The 1.3 liter detector head for this instrument is a composite detector with an organic scintillator containing uniformly distributed {sup 6}Li{sub 6}{sup nat}Gd{sup 10}B{sub 3}O{sub 9}:Ce (LGB:Ce) microcrystals. The plastic scintillator acts to slow impinging neutrons and emits light proportional to the energy lost by the neutrons as they moderate in the detector body. Moderating neutrons that have slowed sufficiently capture in one of the Lithium-6, Boron-10, or Gadolinium-157 atoms in the LGB:Ce scintillator, which then releases the capture energy in a characteristic cerium emission pulse. The measured captured pulses indicate the presence of neutrons. When a scintillating fluor is present in the plastic, the light pulse resulting from the neutron moderating in the plastic is paired with the LGB:Ce capture pulse to identify the energy of the neutron. About 2% of the impinging neutrons lose all of their energy in a single collision with the detector. There is a linear relationship between the pulse areas of this group of neutrons and energy. The other 98% of neutrons have a wide range of collision histories within the detector body. When these neutrons are 'binned' into energy groups, each group contains a distribution of pulse areas. This data was used to assist in the unfolding of the neutron spectra. The unfolded spectra were then validated with known spectra, at both neutron emitting isotopes and fission/accelerator facilities. Having validated spectra, the dose equivalent and dose rate are determined by applying standard, regulatory damage coefficients to the measured neutron counts for each energy bin of the spectra. Testing

  6. Calibration of the JET neutron yield monitors using the delayed neutron counting technique

    International Nuclear Information System (INIS)

    van Belle, P.; Jarvis, O.N.; Sadler, G.; de Leeuw, S.; D'Hondt, P.; Pillon, M.

    1990-01-01

    The time-resolved neutron yield is routinely measured on the JET tokamak using a set of fission chambers. At present, the preferred technique is to employ activation reactions to determine the neutron fluence at a well-chosen position and to relate the measured fluence to the total neutron emission by means of neutron transport calculations. The delayed neutron counting method is a particularly convenient method of performing the activation measurement and the fission cross sections are accurately known. This paper outlines the measurement technique as used on JET

  7. A measurement of the absolute neutron beam polarization produced by an optically pumped 3He neutron spin filter

    International Nuclear Information System (INIS)

    Rich, D.R.; Bowman, J.D.; Crawford, B.E.; Delheij, P.P.J.; Espy, M.A.; Haseyama, T.; Jones, G.; Keith, C.D.; Knudson, J.; Leuschner, M.B.; Masaike, A.; Masuda, Y.; Matsuda, Y.; Penttilae, S.I.; Pomeroy, V.R.; Smith, D.A.; Snow, W.M.; Szymanski, J.J.; Stephenson, S.L.; Thompson, A.K.; Yuan, V.

    2002-01-01

    The capability of performing accurate absolute measurements of neutron beam polarization opens a number of exciting opportunities in fundamental neutron physics and in neutron scattering. At the LANSCE pulsed neutron source we have measured the neutron beam polarization with an absolute accuracy of 0.3% in the neutron energy range from 40 meV to 10 eV using an optically pumped polarized 3 He spin filter and a relative transmission measurement technique. 3 He was polarized using the Rb spin-exchange method. We describe the measurement technique, present our results, and discuss some of the systematic effects associated with the method

  8. Performance, Accuracy and Efficiency Evaluation of a Three-Dimensional Whole-Core Neutron Transport Code AGENT

    International Nuclear Information System (INIS)

    Jevremovic, Tatjana; Hursin, Mathieu; Satvat, Nader; Hopkins, John; Xiao, Shanjie; Gert, Godfree

    2006-01-01

    The AGENT (Arbitrary Geometry Neutron Transport) an open-architecture reactor modeling tool is deterministic neutron transport code for two or three-dimensional heterogeneous neutronic design and analysis of the whole reactor cores regardless of geometry types and material configurations. The AGENT neutron transport methodology is applicable to all generations of nuclear power and research reactors. It combines three theories: (1) the theory of R-functions used to generate real three-dimensional whole-cores of square, hexagonal or triangular cross sections, (2) the planar method of characteristics used to solve isotropic neutron transport in non-homogenized 2D) reactor slices, and (3) the one-dimensional diffusion theory used to couple the planar and axial neutron tracks through the transverse leakage and angular mesh-wise flux values. The R-function-geometrical module allows a sequential building of the layers of geometry and automatic sub-meshing based on the network of domain functions. The simplicity of geometry description and selection of parameters for accurate treatment of neutron propagation is achieved through the Boolean algebraic hierarchically organized simple primitives into complex domains (both being represented with corresponding domain functions). The accuracy is comparable to Monte Carlo codes and is obtained by following neutron propagation through real geometrical domains that does not require homogenization or simplifications. The efficiency is maintained through a set of acceleration techniques introduced at all important calculation levels. The flux solution incorporates power iteration with two different acceleration techniques: Coarse Mesh Re-balancing (CMR) and Coarse Mesh Finite Difference (CMFD). The stand-alone originally developed graphical user interface of the AGENT code design environment allows the user to view and verify input data by displaying the geometry and material distribution. The user can also view the output data such

  9. Neutron diffraction for studying the influence of the relative humidity on the carbonation process of cement pastes

    International Nuclear Information System (INIS)

    Galan, I; Andrade, C; Castellote, M; Rebolledo, N; Sanchez, J; Toro, L; Puente, I; Campo, J; Fabelo, O

    2011-01-01

    The effect of humidity on hydrated cement carbonation has been studied by means of in-situ neutron diffraction measurements. The evolution of the main crystalline phases in the bulk of the sample, portlandite and calcite, has been monitored during the process. Data obtained from neutron diffraction allow the quantification of the phases involved. The results highlight the great influence of humidity on carbonation. At very low humidity there are almost no changes. Between 53 and 75% relative humidity, portlandite decrease and calcite increase data can be fitted to exponential decay functions. At very high humidity portlandite remains nearly constant while calcite increases slightly with time, almost linearly.

  10. Calculations of the relative effectiveness of alanine for neutrons with energies up to 17.1 MeV

    International Nuclear Information System (INIS)

    Gerstenberg, H.M.; Coyne, J.J.

    1990-01-01

    The relative effectiveness (RE) of alanine has been calculated for neutrons using the RE of alanine for charged particles. The neutrons interact with one or more of the elements (hydrogen, carbon, nitrogen and oxygen) that compose the alanine. These interactions produce spectra of secondary charged particles consisting of ions of H, D, He, Be, B, C, N and O. From a combination of the calculated secondary charged particle spectra generated by the slowing down neutrons, and the calculated RE of the ions produced, a RE for the neutrons can be obtained. In addition, lineal energy spectra were determined for neutrons with energies up to 17.1 MeV interacting with alanine. An analytical code was used to calculate these spectra for a 1 μm diameter alanine cell surrounded by an alanine medium. For comparison, similar calculations were made for muscle tissue. Finally, the calculated differential RE was folded with dose distributions to obtain RE-weighted distributions for alanine. (author)

  11. Experiments on the Biological Action of Neutrons Performed in the Former Soviet Union: A Historical Review

    Science.gov (United States)

    2006-10-01

    Exposed to x-rays and Fission Neutrons at Different Stages of Postnatal Development. Radio- biologia , 1982, vol. 22, no. 1, pp. 76-81. 10. Bogatyrev A.V...Cyclotron U-120. Radio- biologia , vol. 24, no. 4, pp. 567-569, 1986. 17. Dokshina G.A., Naumenko L.A., Effect of Mixed Gamma-Neutron Radia- tion on...in Drosophila Spermatogenesis on Dose from Fast Neutrons. Radio- biologia , v. 2, no. 3, pp. 420-421, 1963. 4. Alexandrov I.D., Different RBE for Gene

  12. Relative measurements of fast neutron contamination in 18-MV photon beams from two linear accelerators and a betatron

    International Nuclear Information System (INIS)

    Gur, D.; Bukovitz, A.G.; Rosen, J.C.; Holmes, B.G.

    1979-01-01

    Fast neutron contamination in photon beams in the 20 MV range have been reported in recent years. In order to determine if the variations were due mainly to differences in measurement procedures, or inherent in the design of the accelerators, three different 18-MV (BJR) photon beams were compared using identical analytical techniques. The units studied were a Philips SL/75-20 and a Siemens Mevatron-20 linear accelerators and a Schimadzu betatron. Gamma spectroscopy of an activated aluminum foil was the method used. By comparing the relative amounts of neutron contamination, errors associated with absolute measurements such as detector efficiency and differences in activation foils were eliminated. Fast neutron contaminations per rad of x rays in a ratio of 6.7:3.7:1 were found for the Philips, Schimadzu and Siemens accelerators, respectively

  13. The relative biological effectiveness of fractionated doses of fast neutrons (42 MeVd→Be) for normal tissues. Pt. 3

    International Nuclear Information System (INIS)

    Rezvani, M.; Hopewell, J.W.; Robbins, M.E.C.; Hamlet, R.; Barnes, D.W.H.; Sansom, J.M.; Adams, P.J.V.

    1990-01-01

    The effect of single and fractionated doses of fast neutrons (42 MeV d→Bc ) on the early and late radiation responses of the pig lung have been assessed by the measurement of changes in lung function using a 133 Xe washout technique. The results obtained for irradiation schedules with fast neutrons have been compared with those after photon irradiation. There was no statistically significant difference between the values for the relative biological effectiveness (RBE) for the early and late radiation response of the lung. The RBE of the neutron beam increased with decreasing size of dose/fraction with an upper limit value of 4.39 ± 0.94 for infinitely small X-ray doses per fraction. (author)

  14. The relation between conscientiousness, empowerment and performance

    Directory of Open Access Journals (Sweden)

    Riëtte Sutherland

    2007-02-01

    Full Text Available This study examined the relationship between conscientiousness, empowerment and job performance among information technology professionals. An Employee Empowerment Questionnaire (EEQ, a Conscientiousness Scale and a Social Desirability Scale were administered to 101 information technology customer service engineers. Managers completed a Performance Evaluation Questionnaire (PEQ for each customer service engineer. The results indicated a significant relationship between conscientiousness and empowerment. A curvilinear relationship was found between empowerment and performance. The practical and theoretical implications of the findings are discussed.

  15. Simulations and measurements of the performance of a channeled neutron guide for a time-of-flight spectrometer at the NIST Center for Neutron Research

    International Nuclear Information System (INIS)

    Cook, Jeremy C.; Copley, John R.D.

    2004-01-01

    We describe the identification and analysis of the principal sources of intensity loss within the five-channeled neutron guide tube that was originally installed in the chopper section of the Disk Chopper Spectrometer at the National Institute of Standards and Technology Center for Neutron Research. (The purpose of the five channels was to optimize intensity and resolution in three different modes of operation known as ''resolution modes.'') By combining measurements, Monte Carlo simulations, and analytical calculations, we have developed a model that successfully explains performance losses in the original guide. We have used this model to quantify expected returns in performance using a replacement guide in which the principal contributions to the intensity loss are reduced to the minimum achievable with current technology. We have also estimated the intensity gains that would be achieved if one of the limited number of options were adopted for modifying the original guide in a manner likely to produce such gains. We describe factors that affect the performance of the original guide and compare the measured and predicted performance of the modified guide against predictions for the optimal replacement guide. The simulations indicate that the modified guide (which has three channels rather than the original five) produces greater intensity gains over a large incident wavelength band for the low and medium resolution modes, whereas a high quality replacement guide greatly improves performance in the high resolution mode of operation. Because the low and medium resolution modes are most heavily demanded, we opted to modify the guide rather than replace it. We describe the nature of this modification and present intensity measurements that meet or exceed predictions in all resolution modes with no detectable change in the energy resolution nor increase in the instrumental background

  16. Fatigue performance of copper and copper alloys before and after irradiation with fission neutrons

    International Nuclear Information System (INIS)

    Singh, B.N.; Toft, P.; Stubbins, J.F.

    1997-05-01

    The fatigue performance of pure copper of the oxygen free, high conductivity (OFHC) grade and two copper alloys (CuCrZr and CuAl-25) was investigated. Mechanical testing and microstructural analysis were carried out to establish the fatigue life of these materials in the unirradiated and irradiated states. The present report provides the first information on the ability of these copper alloys to perform under cyclic loading conditions when they have undergone significant irradiation exposure. Fatigue specimens of OFHC-Cu, CuCrZr and CuAl-25 were irradiated with fission neutrons in the DR-3 reactor at Risoe with a flux of ∼2.5 x 10 17 n/m 2 s (E > 1 MeV) to fluence levels of 1.5 - 2.5 x 10 24 n/m 2 s (E > 1 MeV) at ∼47 and 100 deg. C. Specimens irradiated at 47 deg. C were fatigue tested at 22 deg. C, whereas those irradiated at 100 deg. C were tested at the irradiation temperature. The major conclusion of the present work is that although irradiation causes significant hardening of copper and copper alloys, it does not appear to be a problem for the fatigue life of these materials. In fact, the present experimental results clearly demonstrate that the fatigue performance of the irradiated CuAl-25 alloy is considerably better in the irradiated than that in the unirradiated state tested both at 22 and 100 deg. C. This improvement, however, is not so significant in the case of the irradiated OFHC-copper and CuCrZr alloy tested at 22 deg. C. These conclusions are supported by the microstructural observations and cyclic hardening experiments. (au) 4 tabs., 26 ills., 10 refs

  17. Neutronic performance calculations with alternative fluids in a hybrid reactor by using the Monte Carlo method

    Energy Technology Data Exchange (ETDEWEB)

    Guenay, Mehtap [Malatya Univ. (Turkey). Physics Department

    2015-03-15

    In this study, salt-heavy metal mixtures consisting of 93-85% Li{sub 20}Sn{sub 80} + 5% SFG-PuO{sub 2} and 2-10% UO{sub 2}, 93-85% Li{sub 20}Sn{sub 80} + 5% SFG-PuO{sub 2} and 2-10% NpO{sub 2}, and 93-85% Li{sub 20}Sn{sub 80} + 5% SFG-PuO{sub 2} and 2-10% UCO were used as fluids. The fluids were used in the liquid first wall, blanket, and shield zones of a fusion-fission hybrid reactor system. A beryllium (Be) zone with a width of 3 cm was used for neutron multiplicity between the liquid first wall and the blanket. 9Cr2WVTa ferritic steel with the width of 4 cm was used as the structural material. The contributions of each isotope in the fluids to the nuclear parameters, such as tritium breeding ratio (TBR), energy multiplication factor (M), and heat deposition rate, of the fusion-fission hybrid reactor were calculated in the liquid first wall, blanket, and shield zones. Three-dimensional analyses were performed using the Monte Carlo code MCNPX-2.7.0 and nuclear data library ENDF/B-VII.0.

  18. Measured performances on vectorization and multitasking with a Monte Carlo code for neutron transport problems

    International Nuclear Information System (INIS)

    Chauvet, Y.

    1985-01-01

    This paper summarized two improvements of a real production code by using vectorization and multitasking techniques. After a short description of Monte Carlo algorithms employed in neutron transport problems, the authors briefly describe the work done in order to get a vector code. Vectorization principles are presented and measured performances on the CRAY 1S, CYBER 205 and CRAY X-MP compared in terms of vector lengths. The second part of this work is an adaptation to multitasking on the CRAY X-MP using exclusively standard multitasking tools available with FORTRAN under the COS 1.13 system. Two examples are presented. The goal of the first one is to measure the overhead inherent to multitasking when tasks become too small and to define a granularity threshold, that is to say a minimum size for a task. With the second example they propose a method that is very X-MP oriented in order to get the best speedup factor on such a computer. In conclusion they prove that Monte Carlo algorithms are very well suited to future vector and parallel computers

  19. Measured performances on vectorization and multitasking with a Monte Carlo code for neutron transport problems

    International Nuclear Information System (INIS)

    Chauvet, Y.

    1985-01-01

    This paper summarized two improvements of a real production code by using vectorization and multitasking techniques. After a short description of Monte Carlo algorithms employed in our neutron transport problems, we briefly describe the work we have done in order to get a vector code. Vectorization principles will be presented and measured performances on the CRAY 1S, CYBER 205 and CRAY X-MP compared in terms of vector lengths. The second part of this work is an adaptation to multitasking on the CRAY X-MP using exclusively standard multitasking tools available with FORTRAN under the COS 1.13 system. Two examples will be presented. The goal of the first one is to measure the overhead inherent to multitasking when tasks become too small and to define a granularity threshold, that is to say a minimum size for a task. With the second example we propose a method that is very X-MP oriented in order to get the best speedup factor on such a computer. In conclusion we prove that Monte Carlo algorithms are very well suited to future vector and parallel computers. (orig.)

  20. Neutronic performance calculations with alternative fluids in a hybrid reactor by using the Monte Carlo method

    International Nuclear Information System (INIS)

    Guenay, Mehtap

    2015-01-01

    In this study, salt-heavy metal mixtures consisting of 93-85% Li 20 Sn 80 + 5% SFG-PuO 2 and 2-10% UO 2 , 93-85% Li 20 Sn 80 + 5% SFG-PuO 2 and 2-10% NpO 2 , and 93-85% Li 20 Sn 80 + 5% SFG-PuO 2 and 2-10% UCO were used as fluids. The fluids were used in the liquid first wall, blanket, and shield zones of a fusion-fission hybrid reactor system. A beryllium (Be) zone with a width of 3 cm was used for neutron multiplicity between the liquid first wall and the blanket. 9Cr2WVTa ferritic steel with the width of 4 cm was used as the structural material. The contributions of each isotope in the fluids to the nuclear parameters, such as tritium breeding ratio (TBR), energy multiplication factor (M), and heat deposition rate, of the fusion-fission hybrid reactor were calculated in the liquid first wall, blanket, and shield zones. Three-dimensional analyses were performed using the Monte Carlo code MCNPX-2.7.0 and nuclear data library ENDF/B-VII.0.

  1. A low noise ASIC for two dimensional neutron gas detector with performance of high spatial resolution (Contract research)

    International Nuclear Information System (INIS)

    Yamagishi, Hideshi; Toh, Kentaro; Nakamura, Tatsuya; Sakasai, Kaoru; Soyama, Kazuhiko

    2012-02-01

    An ASD-ASIC (Amplifier-Shaper-Discriminator ASIC) with fast response and low noise performances has been designed for two-dimensional position sensitive neutron gas detectors (InSPaD). The InSPaD is a 2D neutron detector system with 3 He gas and provides a high spatial resolution by making distinction between proton and triton particles generated in the gas chamber. The new ASD-ASIC is required to have very low noise, a wide dynamic range, good output linearity and high counting rate. The new ASD-ASIC has been designed by using CMOS and consisted of 64-channel ASDs, a 16-channel multiplexer with LVTTL drivers and sum amplifier system for summing all analog signals. The performances were evaluated by the Spice simulation. It was confirmed that the new ASD-ASIC had very low noise performance, wide dynamic range and fast signal processing functions. (author)

  2. Radiolabeling of intact dosage forms by neutron activation: effects on in vitro performance

    International Nuclear Information System (INIS)

    Parr, A.; Jay, M.

    1987-01-01

    Compressed tablets containing various quantities of stable isotopes of Ba, Er, and Sm for use in neutron activation studies were evaluated for the effect of stable isotope incorporation on tablet hardness and disintegration times. At concentrations likely to be used in scintigraphic studies employing neutron activation as a radiolabeling method, no significant effect on in vitro parameters were observed. While the incorporation of stable isotopes influenced tablet hardness to a greater degree than disintegration time, irradiation of tablets in a neutron flux of 4.4 x 10(13) n/cm2 sec had a direct effect on tablet disintegration time. Thus, future neutron activation studies should focus on minimizing the amount of stable isotope to be incorporated with the formulation while using the shortest feasible irradiation time

  3. Correlation of microdosimetric measurements with relative biological effectiveness from clinical experience for two neutron therapy beams

    International Nuclear Information System (INIS)

    Stinchcomb, T.G.; Kuchnir, F.T.; Myrianthopoulos, L.C.; Horton, J.L. Jr.; Roberts, W.K.

    1986-01-01

    Microdosimetric measurements were made for the neutron therapy beams at the University of Chicago and at the Cleveland Clinic with the same geometry and phantom material using the same tissue-equivalent spherical proportional counter and standard techniques. The energy deposition spectra (dose distributions in lineal energy) are compared for these beams and for their scattered components (direct beam blocked). The model of dual radiation action (DRA) of Kellerer and Rossi is employed to interpret these data in terms of biological effectiveness over this limited range of radiation qualities. The site-diameter parameter of the DRA theory is determined for the Cleveland beam by setting the biological effectiveness (relative to 60 Co gamma radiation) equal to the relative biological effectiveness value deduced from radiobiology experiments and clinical experience. The resulting value of this site-diameter parameter is then used to predict the biological effectiveness of the Chicago beam. The prediction agrees with the value deduced from radiobiology and clinical experience. The biological effectiveness of the scattered components of both beams is also estimated using the model

  4. Characterization of weak, fair and strong neutron absorbing materials by means of neutron transmission: Beam hardening effect

    Science.gov (United States)

    Kharfi, F.; Bastuerk, M.; Boucenna, A.

    2006-09-01

    The characterization of neutron absorbing materials as well as quantification of neutron attenuation through matter is very essential in various fields, namely in shielding calculation. The objective of this work is to describe an experimental procedure to be used for the determination of neutron transmission through different materials. The proposed method is based on the relation between the gray value measured on neutron radiography image and the corresponding inducing neutron beam. For such a purpose, three kinds of materials (in shape of plate) were investigated using thermal neutrons: (1) boron-alloyed stainless steel as strong absorber; (2) copper and steel as fair absorbers and (3) aluminum as weak absorber. This work is not limited to the determination of neutron transmission through matters; it is also spread out to the measure of the surface density of the neutron absorbing elements (ρs) as a function of thickness of neutron absorbing material such as boron-alloyed stainless steel. The beam hardening effect depending on material thickness was also studied using the neutron transmission measurements. A theoretical approach was used to interpret the experimental results. The neutron transmission measurements were performed at the Neutron Radiography and Tomography facility of the Atomic Institute of the Austrian Universities in Vienna. Finally, a Maxwellian neutron distribution of incident neutron beam was used in the theoretical calculations of neutron energy shift in order to compare with experiments results. The obtained experimental results are in a good agreement with the developed theoretical approach.

  5. Reference radiation fields - Simulated workplace neutron fields - Part 2: Calibration fundamentals related to the basic quantities

    International Nuclear Information System (INIS)

    2008-01-01

    ISO 8529-1, ISO 8529-2 and ISO 8529-3, deal with the production, characterization and use of neutron fields for the calibration of personal dosimeters and area survey meters. These International Standards describe reference radiations with neutron energy spectra that are well defined and well suited for use in the calibration laboratory. However, the neutron spectra commonly encountered in routine radiation protection situations are, in many cases, quite different from those produced by the sources specified in the International Standards. Since personal neutron dosimeters, and to a lesser extent survey meters, are generally quite energy dependent in their dose equivalent response, it might not be possible to achieve an appropriate calibration for a device that is used in a workplace where the neutron energy spectrum and angular distribution differ significantly from those of the reference radiation used for calibration. ISO 8529-1 describes four radionuclide based neutron reference radiations in detail. This part of ISO 12789 includes the specification of neutron reference radiations that were developed to closely resemble radiation that is encountered in practice

  6. The Clatterbridge high-energy neutron therapy facility: specification and performance

    International Nuclear Information System (INIS)

    Bonnett, D.E.; Blake, S.W.; Shaw, J.E.; Bewley, D.K.

    1988-01-01

    A high energy neutron therapy facility has been installed at the Douglas Cyclotron Centre, Clatterbridge Hospital Merseyside, to extend M.R.C. clinical trials of fast neutrons. The neutron beam is produced by bombarding a beryllium target with 62 MeV protons. The target is isocentrically mounted with potential for 360 0 rotation, with a fully variable collimator, giving a range of rectilinear field sizes from 5 cm x 5 cm to 30 cm x 30 cm. Basic neutron beam data including output, field flatness, penumbra and depth-dose data have been measured. For a 10 cm x 10 cm field, 50% depth dose occurs at 16.2 cm in water and output is 1.63 cGy μ A -1 min -1 at maximum dose depth. Effectiveness of the target shielding and neutron-induced radioactivity in the treatment head were also measured. It is concluded that the equipment meets design specifications and fully satisfies criticisms of earlier neutron therapy equipment. A full radiation survey showed that radiation levels present no significant staff hazard. (UK)

  7. Neutron scattering

    International Nuclear Information System (INIS)

    Furrer, A.

    1993-01-01

    This report contains the text of 16 lectures given at the Summer School and the report on a panel discussion entitled ''the relative merits and complementarities of x-rays, synchrotron radiation, steady- and pulsed neutron sources''. figs., tabs., refs

  8. Neutron relative biological effectiveness for solid cancer incidence in the Japanese A-bomb survivors: an analysis considering the degree of independent effects from γ-ray and neutron absorbed doses with hierarchical partitioning

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, Linda [Federal Office for Radiation Protection, Department Radiation Protection and Health, Oberschleissheim (Germany); University of Manchester, The Faculty of Medical and Human Sciences, Manchester (United Kingdom)

    2013-03-15

    It has generally been assumed that the neutron and γ-ray absorbed doses in the data from the life span study (LSS) of the Japanese A-bomb survivors are too highly correlated for an independent separation of the all solid cancer risks due to neutrons and due to γ-rays. However, with the release of the most recent data for all solid cancer incidence and the increased statistical power over previous datasets, it is instructive to consider alternatives to the usual approaches. Simple excess relative risk (ERR) models for radiation-induced solid cancer incidence fitted to the LSS epidemiological data have been applied with neutron and γ-ray absorbed doses as separate explanatory covariables. A simple evaluation of the degree of independent effects from γ-ray and neutron absorbed doses on the all solid cancer risk with the hierarchical partitioning (HP) technique is presented here. The degree of multi-collinearity between the γ-ray and neutron absorbed doses has also been considered. The results show that, whereas the partial correlation between the neutron and γ-ray colon absorbed doses may be considered to be high at 0.74, this value is just below the level beyond which remedial action, such as adding the doses together, is usually recommended. The resulting variance inflation factor is 2.2. Applying HP indicates that just under half of the drop in deviance resulting from adding the γ-ray and neutron absorbed doses to the baseline risk model comes from the joint effects of the neutrons and γ-rays - leaving a substantial proportion of this deviance drop accounted for by individual effects of the neutrons and γ-rays. The average ERR/Gy γ-ray absorbed dose and the ERR/Gy neutron absorbed dose that have been obtained here directly for the first time, agree well with previous indirect estimates. The average relative biological effectiveness (RBE) of neutrons relative to γ-rays, calculated directly from fit parameters to the all solid cancer ERR model with both

  9. Simulated Performance of the Integrated Passive Neutron Albedo Reactivity and Self-Interrogation Neutron Resonance Densitometry Detector Designed for Spent Fuel Measurement at the Fugen Reactor in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Ulrich, Timothy J. II [Los Alamos National Laboratory; Lafleur, Adrienne M. [Los Alamos National Laboratory; Menlove, Howard O. [Los Alamos National Laboratory; Swinhoe, Martyn T. [Los Alamos National Laboratory; Tobin, Stephen J. [Los Alamos National Laboratory; Seya, Michio [Los Alamos National Laboratory; Bolind, Alan M. [Los Alamos National Laboratory

    2012-07-16

    An integrated nondestructive assay instrument, which combined the Passive Neutron Albedo Reactivity (PNAR) and the Self-Interrogation Neutron Resonance Densitometry (SINRD) techniques, is the research focus for a collaborative effort between Los Alamos National Laboratory (LANL) and the Japanese Atomic Energy Agency as part of the Next Generation Safeguard Initiative. We will quantify the anticipated performance of this experimental system in two physical environments: (1) At LANL we will measure fresh Low Enriched Uranium (LEU) assemblies for which the average enrichment can be varied from 0.2% to 3.2% and for which Gd laced rods will be included. (2) At Fugen we will measure spent Mixed Oxide (MOX-B) and LEU spent fuel assemblies from the heavy water moderated Fugen reactor. The MOX-B assemblies will vary in burnup from {approx}3 GWd/tHM to {approx}20 GWd/tHM while the LEU assemblies ({approx}1.9% initial enrichment) will vary from {approx}2 GWd/tHM to {approx}7 GWd/tHM. The estimated count rates will be calculated using MCNPX. These preliminary results will help the finalization of the hardware design and also serve a guide for the experiment. The hardware of the detector is expected to be fabricated in 2012 with measurements expected to take place in 2012 and 2013. This work is supported by the Next Generation Safeguards Initiative, Office of Nuclear Safeguards and Security, National Nuclear Security Administration.

  10. Neutron cross section measurements at n-TOF for ADS related studies

    Science.gov (United States)

    Mastinu, P. F.; Abbondanno, U.; Aerts, G.; Álvarez, H.; Alvarez-Velarde, F.; Andriamonje, S.; Andrzejewski, J.; Assimakopoulos, P.; Audouin, L.; Badurek, G.; Bustreo, N.; aumann, P.; vá, F. Be; Berthoumieux, E.; Calviño, F.; Cano-Ott, D.; Capote, R.; Carrillo de Albornoz, A.; Cennini, P.; Chepel, V.; Chiaveri, E.; Colonna, N.; Cortes, G.; Couture, A.; Cox, J.; Dahlfors, M.; David, S.; Dillmann, I.; Dolfini, R.; Domingo-Pardo, C.; Dridi, W.; Duran, I.; Eleftheriadis, C.; Embid-Segura, M.; Ferrant, L.; Ferrari, A.; Ferreira-Marques, R.; itzpatrick, L.; Frais-Kölbl, H.; Fujii, K.; Furman, W.; Guerrero, C.; Goncalves, I.; Gallino, R.; Gonzalez-Romero, E.; Goverdovski, A.; Gramegna, F.; Griesmayer, E.; Gunsing, F.; Haas, B.; Haight, R.; Heil, M.; Herrera-Martinez, A.; Igashira, M.; Isaev, S.; Jericha, E.; Kadi, Y.; Käppeler, F.; Karamanis, D.; Karadimos, D.; Kerveno, M.; Ketlerov, V.; Koehler, P.; Konovalov, V.; Kossionides, E.; Krti ka, M.; Lamboudis, C.; Leeb, H.; Lindote, A.; Lopes, I.; Lozano, M.; Lukic, S.; Marganiec, J.; Marques, L.; Marrone, S.; Massimi, C.; Mengoni, A.; Milazzo, P. M.; Moreau, C.; Mosconi, M.; Neves, F.; Oberhummer, H.; O'Brien, S.; Oshima, M.; Pancin, J.; Papachristodoulou, C.; Papadopoulos, C.; Paradela, C.; Patronis, N.; Pavlik, A.; Pavlopoulos, P.; Perrot, L.; Plag, R.; Plompen, A.; Plukis, A.; Poch, A.; Pretel, C.; Quesada, J.; Rauscher, T.; Reifarth, R.; Rosetti, M.; Rubbia, C.; Rudolf, G.; Rullhusen, P.; Salgado, J.; Sarchiapone, L.; Savvidis, I.; Stephan, C.; Tagliente, G.; Tain, J. L.; Tassan-Got, L.; Tavora, L.; Terlizzi, R.; Vannini, G.; Vaz, P.; Ventura, A.; Villamarin, D.; Vincente, M. C.; Vlachoudis, V.; Vlastou, R.; Voss, F.; Walter, S.; Wendler, H.; Wiescherand, M.; Wisshak, K.

    2006-05-01

    A neutron Time-of-Flight facility (n_TOF) is available at CERN since 2001. The innovative features of the neutron beam, in particular the high instantaneous flux, the wide energy range, the high resolution and the low background, make this facility unique for measurements of neutron induced reactions relevant to the field of Emerging Nuclear Technologies, as well as to Nuclear Astrophysics and Fundamental Nuclear Physics. The scientific motivations that have led to the construction of this new facility are here presented. The main characteristics of the n_TOF neutron beam are described, together with the features of the experimental apparata used for cross-section measurements. The main results of the first measurement campaigns are presented. Preliminary results of capture cross-section measurements of minor actinides, important to ADS project for nuclear waste transmutation, are finally discussed.

  11. Neutron cross section measurements at n-TOF for ADS related studies

    International Nuclear Information System (INIS)

    Mastinu, P F; Abbondanno, U; Aerts, G

    2006-01-01

    A neutron Time-of-Flight facility (n T OF) is available at CERN since 2001. The innovative features of the neutron beam, in particular the high instantaneous flux, the wide energy range, the high resolution and the low background, make this facility unique for measurements of neutron induced reactions relevant to the field of Emerging Nuclear Technologies, as well as to Nuclear Astrophysics and Fundamental Nuclear Physics. The scientific motivations that have led to the construction of this new facility are here presented. The main characteristics of the n T OF neutron beam are described, together with the features of the experimental apparata used for cross-section measurements. The main results of the first measurement campaigns are presented. Preliminary results of capture cross-section measurements of minor actinides, important to ADS project for nuclear waste transmutation, are finally discussed

  12. Neutron cross section measurements at n-TOF for ADS related studies

    CERN Document Server

    Mastinu, P F; Aerts, G; Alvarez, H; Alvarez-Velarde, F; Andriamonje, Samuel A; Andrzejewski, J; Assimakopoulos, P A; Audouin, L; Badurek, G; Bustreo, N; Aumann, P; Beva, F; Berthoumieux, E; Calviño, F; Cano-Ott, D; Capote, R; Carillo de Albornoz, A; Cennini, P; Chepel, V; Chiaveri, Enrico; Colonna, N; Cortés, G; Couture, A; Cox, J; Dahlfors, M; David, S; Dillmann, I; Dolfini, R; Domingo-Pardo, C; Dridi, W; Durán, I; Eleftheriadis, C; Segura, M E; Ferrant, L; Ferrari, A; Ferreira-Marques, R; itzpatrick, L; Frais-Kölbl, H; Fujii, K; Furman, W; Guerrero, C; Gonçalves, I; Gallino, R; González-Romero, E M; Goverdovski, A; Gramegna, F; Griesmayer, E; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martínez, A; Igashira, M; Isaev, S; Jericha, E; Kadi, Y; Käppeler, F K; Karamanis, D; Karadimos, D; Kerveno, M; Ketlerov, V; Köhler, P; Konovalov, V; Kossionides, E; Krticka, M; Lamboudis, C; Leeb, H; Lindote, A; Lopes, I; Lozano, M; Lukic, S; Marganiec, J; Marques, L; Marrone, S; Massimi, C; Mengoni, A; Milazzo, P M; Moreau, C; Mosconi, M; Neves, F; Oberhummer, Heinz; O'Brien, S; Oshima, M; Pancin, J; Papachristodoulou, C; Papadopoulos, C; Paradela, C; Patronis, N; Pavlik, A; Pavlopoulos, P; Perrot, L; Plag, R; Plompen, A; Plukis, A; Poch, A; Pretel, C; Quesada, J; Rauscher, T; Reifarth, R; Rosetti, M; Rubbia, Carlo; Rudolf, G; Rullhusen, P; Salgado, J; Sarchiapone, L; Savvidis, I; Stéphan, C; Tagliente, G; Taín, J L; Tassan-Got, L; Tavora, L; Terlizzi, R; Vannini, G; Vaz, P; Ventura, A; Villamarín, D; Vincente, M C; Vlachoudis, V; Vlastou, R; Voss, F; Walter, S; Wendler, H; Wiescherand, M; Wisshak, K

    2006-01-01

    A neutron Time-of-Flight facility (n_TOF) is available at CERN since 2001. The innovative features of the neutron beam, in particular the high instantaneous flux, the wide energy range, the high resolution and the low background, make this facility unique for measurements of neutron induced reactions relevant to the field of Emerging Nuclear Technologies, as well as to Nuclear Astrophysics and Fundamental Nuclear Physics. The scientific motivations that have led to the construction of this new facility are here presented. The main characteristics of the n_TOF neutron beam are described, together with the features of the experimental apparata used for cross-section measurements. The main results of the first measurement campaigns are presented. Preliminary results of capture cross-section measurements of minor actinides, important to ADS project for nuclear waste transmutation, are finally discussed.

  13. Evaluation of Neutron-induced Cross Sections and their Related Covariances with Physical Constraints

    Science.gov (United States)

    De Saint Jean, C.; Archier, P.; Privas, E.; Noguère, G.; Habert, B.; Tamagno, P.

    2018-02-01

    Nuclear data, along with numerical methods and the associated calculation schemes, continue to play a key role in reactor design, reactor core operating parameters calculations, fuel cycle management and criticality safety calculations. Due to the intensive use of Monte-Carlo calculations reducing numerical biases, the final accuracy of neutronic calculations increasingly depends on the quality of nuclear data used. This paper gives a broad picture of all ingredients treated by nuclear data evaluators during their analyses. After giving an introduction to nuclear data evaluation, we present implications of using the Bayesian inference to obtain evaluated cross sections and related uncertainties. In particular, a focus is made on systematic uncertainties appearing in the analysis of differential measurements as well as advantages and drawbacks one may encounter by analyzing integral experiments. The evaluation work is in general done independently in the resonance and in the continuum energy ranges giving rise to inconsistencies in evaluated files. For future evaluations on the whole energy range, we call attention to two innovative methods used to analyze several nuclear reaction models and impose constraints. Finally, we discuss suggestions for possible improvements in the evaluation process to master the quantification of uncertainties. These are associated with experiments (microscopic and integral), nuclear reaction theories and the Bayesian inference.

  14. Study of organohalogens in foodstuffs and environmental samples by neutron activation analysis and related techniques

    International Nuclear Information System (INIS)

    Xu, D. D.; Mao, X.Y.; Ouyang, H.; Chai, Z. F.; Zhang, H.; Sun, H. B.

    2004-01-01

    Pine needles and foodstuffs collected from Beijing, China, were analyzed by instrumental neutron activation analysis (INAA) combined with organic solvent extraction for total halogens, extractable organohalogens (EOX) and extractable persistent organohalogens (EPOX). The INAA detection limits are 50 ng, 8 ng and 3.5 ng for Cl, Br and I, respectively. The contents and distribution patterns of organohalogens in these samples are reported. EOCl accounted for 0.013-0.016% and 1.6-2.7% of the total chlorine in yogurt and apples, respectively, which suggested that chlorine in foodstuffs mainly existed as inorganic species and non-extractable organochlorines. EOCl contents in pine needles and foodstuffs were noticeably higher than those of EOBr and EOI. For pine needles, yogurt and apples, 1.6-34%, 23-58% and 29-35% of EOCl remained as extractable persistent organochlorine (EPOCl), respectively. Pine needle containing higher EOCl contents in chemical industrial and traffic hub areas indicated that chemical industries and exhaust emission from vehicle were the main sources of organochlorines in the Beijing's air. The relative proportions of the known organochlorines (such as HCHs, DDTs, chlordanes, heptachlor, HCB and PCBs) to the total EOCl and EPOCl were 0.04-1.6% and 0.7-21.5%, respectively, which implied that the identity of species of a major portion of the EOCl and EPOCl measured in pine needles was unknown. (author)

  15. Multidisk neutron velocity selectors

    International Nuclear Information System (INIS)

    Hammouda, B.

    1992-01-01

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

  16. Neutron stars

    International Nuclear Information System (INIS)

    Irvine, J.M.

    1978-01-01

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

  17. Performance relations in Capacitive Deionization systems

    NARCIS (Netherlands)

    Limpt, van B.

    2010-01-01

    Capacitive Deionization (CDI) is a relatively new deionization technology based on the temporary storage of ions on an electrically charged surface. By directing a flow between two oppositely charged surfaces, negatively charged ions will adsorb onto the positively charged surface, and positively

  18. Performance of an RPM based on Gd-lined plastic scintillator for neutron and gamma detection [ANIMMA--2015-IO-372

    Energy Technology Data Exchange (ETDEWEB)

    Fanchini, Erica [INFN/ANN and SCINTILLA groups, Isituto Nazionale di Fisica Nucleare - INFN (Italy)

    2015-07-01

    A Radiation Portal Monitor (RPM) was developed by the Istituto Nazionale di Fisica Nucleare (INFN) and Ansaldo Nucleare (ANN) within the FP7 SCINTILLA European project. The system was designed to detect both gamma and neutron radiation with a single technology. It is conceived to monitor vehicle and cargo containers in transits across borders or ports, to find radioactive elements and to avoid illegal trafficking of strategic nuclear materials. The system is based on a {sup 3}He-free neutron detection technology using plastic scintillators coupled to Gadolinium to detect and discriminate gamma from neutron signals. During the 3 years of the SCINTILLA project the construction and test of the first two prototypes drove the definition of the final layout of a full RPM system consisting of two twin pillars as a portal for vehicle and cargo container scan. A custom System Control Software (SCS) manages the electronics of the RPM, the ancillary devices and the data analysis. The combination of the detector layout and of the software functionalities enables both to distinguish neutrons and gammas and to identify the energy range of a detected gamma source. The system was initially characterized via static tests with gamma and neutron sources in the INFN laboratory. These measurements were used to calibrate the detector, evaluate the response of the single pillars as well as of the full system, and optimize the RPM configuration and discrimination algorithm. During this phase, specific tests were performed to study the stability over time of the system, monitoring the measured the neutron and gamma count rates over periods of several weeks. The results allow us to demonstrate the reliability and robustness of the RPM. In a second time the RPM performance was studied via dynamic tests performed during the SCINTILLA test and benchmark campaigns. These measurements took place in the JRC ITRAP+10 facility at Ispra (Varese-Italy). The laboratory is equipped with an experimental

  19. Comparison of different methods for activation analysis of geological and pedological samples: Reactor and epithermal neutron activation, relative and monostandard method

    International Nuclear Information System (INIS)

    Alian, A.; Sansoni, B.

    1980-04-01

    Using purely instrumental methods, a comparative study is presented on neutron activation analysis of rock and soil samples by whole reactor neutron spectrum and epithermal neutrons with both relative and monostandard procedures. The latter procedure used with epithermal neutron activation analysis of soil samples necessitated the use of the 'effective resonance integrals' which were determined experimentally. The incorporation of the #betta# factor, representing deviation of reactor epithermal neutron flux from 1/E law, is developed in the present work. The main criteria for the choice of one or more of the procedures studied for a given purpose are also indicated. Analysis of 15 trace elements, Ca and Fe in the standard Japanese granite JG-1 using monostandard epithermal neutron activation gave results in good agreement with the average literature values. (orig./RB) [de

  20. A large, high performance, curved 2D position-sensitive neutron detector

    CERN Document Server

    Fried, J W; Mahler, G J; Makowiecki, D S; Mead, J A; Radeka, V; Schaknowski, N A; Smith, G C; Yu, B

    2002-01-01

    A new position-sensitive neutron detector has been designed and constructed for a protein crystallography station at LANL's pulsed neutron source. This station will be one of the most advanced instruments at a major neutron user facility for protein crystallography, fiber and membrane diffraction. The detector, based on neutron absorption in sup 3 He, has a large sensitive area of 3000 cm sup 2 , angular coverage of 120 deg. , timing resolution of 1 mu s, rate capability in excess of 10 sup 6 s sup - sup 1 , position resolution of about 1.5 mm FWHM, and efficiency >50% for neutrons of interest in the range 1-10 A. Features that are key to these remarkable specifications are the utilization of eight independently operating segments within a single gas volume, fabrication of the detector vessel and internal segments with a radius of curvature of about 70 cm, optimized position readout based on charge division and signal shaping with gated baseline restoration, and engineering design with high-strength aluminum ...

  1. Study on neutron capture cross sections using the filtered neutron beams of 55 keV and 144 keV at the Dalat reactor and related applications

    International Nuclear Information System (INIS)

    Vuong Huu Tan; Nguyen Canh Hai; Pham Ngoc Son; Tran Tuan Anh

    2007-01-01

    In this fundamental research project on nuclear physics in period of 2006, the neutron capture cross sections for the reactions of 139 La (n,γ) 140 La, 152 Sm (n,γ) 153 Sm, 191 Ir (n,γ) 192 Ir and 193 Ir (n,γ) 194 Ir have been measured at 55 keV and 144 keV by the activation method using the filtered neutron beams of the Dalat nuclear research reactor. The cross sections were determined relative to the standard capture cross sections of 197 Au. The samples and standard were prepaid from high purity (99.99%) foil of Au and natural oxide powders of La 2 O 3 , Sm 2 O 3 and IrO 2 . A high efficient HPGe detector (58%) was used to detect the gamma rays, emitted from the activated samples. The absolute efficiency curve of the detector has been precisely calibrated thanks to a set of standard radioisotope sources and a multi-nuclide standard solution, supported by IAEA. The present results were compared with the previous measurements from EXFOR-2003, and the evaluated values of JENDL 3.3 and ENDF/B-6.8. (author)

  2. Performance of the coupled thermalhydraulics/neutron kinetics code R/P/C on workstation clusters and multiprocessor systems

    International Nuclear Information System (INIS)

    Hammer, C.; Paffrath, M.; Boeer, R.; Finnemann, H.; Jackson, C.J.

    1996-01-01

    The light water reactor core simulation code PANBOX has been coupled with the transient analysis code RELAP5 for the purpose of performing plant safety analyses with a three-dimensional (3-D) neutron kinetics model. The system has been parallelized to improve the computational efficiency. The paper describes the features of this system with emphasis on performance aspects. Performance results are given for different types of parallelization, i. e. for using an automatic parallelizing compiler, using the portable PVM platform on a workstation cluster, using PVM on a shared memory multiprocessor, and for using machine dependent interfaces. (author)

  3. The performance and radiation exposure of some neutron probes in measuring the water content of the topsoil layer

    International Nuclear Information System (INIS)

    Arslan, A.; Razzouk, A.K.; Al-Ain, F.

    1997-01-01

    The use of neutron scattering technique for determining the soil surface water content is not popular due to the radiation escaping from the soil surface and the large errors in measurement. To compare the radiation exposure and the performance of different techniques statistically, 3 sites were selected. Five different neutron probe models and different adaptors were used with the depth probes. Exposure to neutrons and γ radiations, at various distances from the probes, were determined. In situ calibration curves were determined using different models of depth probes with a Solo surface reflector block, CPN surface adaptor, and different numbers of plastic Teflon parallelepiped, as well as surface Troxler 3401-B probes. Depth neutron probe readings increased with increasing number of Teflon plastic blocks deposited on the soil surface. The intercept of the straight line regression analysis of CR (count ratio, surface count over standard count) v. percentage water content on a volume basis decreased with increasing number of blocks deposited on the soil surface at all sites. The determination coefficient values of any depth probe with a Solo surface reflector or a block of 4-8 cm thickness were higher than those of a Troxler 3401-B surface probe or CPN 503 depth probe with its surface adaptor. The least exposure to radiation was with a depth probe with surface reflectors. This study proves the possibility of measuring the moisture content of the soil surface by using a depth neutron probe with a block laid on the surface, without danger of receiving the threshold dose of radiation. (authors)

  4. Design of a neutron interrogation cell based on an electron accelerator and performance assessment on 220 liter nuclear waste mock-up drums

    International Nuclear Information System (INIS)

    Sari, A.; Carrel, F.; Laine, F.; Lyoussi, A.

    2013-01-01

    Radiological characterization of nuclear waste drums is an important task for the nuclear industry. The amount of actinides, such as 235 U or 239 Pu, contained in a package can be determined using non-destructive active methods based on the fission process. One of these techniques, known as neutron interrogation, uses a neutron beam to induce fission reactions on the actinides. Optimization of the neutron flux is an important step towards improving this technique. Electron accelerators enable to achieve higher neutron flux intensities than the ones delivered by deuterium-tritium generators traditionally used on neutron interrogation industrial facilities. In this paper, we design a neutron interrogation cell based on an electron accelerator by MCNPX simulation. We carry out photoneutron interrogation measurements on uranium samples placed at the center of 220 liter nuclear waste drums containing different types of matrices. We quantify impact of the matrix on the prompt neutron signal, on the ratio between the prompt and delayed neutron signals, and on the interrogative neutron half-life time. We also show that characteristics of the conversion target of the electron accelerator enable to improve significantly measurement performances. (authors)

  5. Relational Aggression and Academic Performance in Elementary School

    Science.gov (United States)

    Risser, Scott D.

    2013-01-01

    To investigate the relationship between relational aggression and school performance, this study examined the relative and combined associations among relational aggression, overt aggression, and victimization and children's academic performance. Additionally this study examined the relative associations among relational and overt aggression and…

  6. Performance of silicon pad detectors after mixed irradiations with neutrons and fast charged hadrons

    Energy Technology Data Exchange (ETDEWEB)

    Kramberger, G. [Jozef Stefan Institute, Department of Physics, University of Ljubljana, Jamova 39, SI-1000 Ljubljana (Slovenia)], E-mail: Gregor.Kramberger@ijs.si; Cindro, V.; Dolenc, I.; Mandic, I.; Mikuz, M.; Zavrtanik, M. [Jozef Stefan Institute, Department of Physics, University of Ljubljana, Jamova 39, SI-1000 Ljubljana (Slovenia)

    2009-10-11

    A large set of silicon pad detectors produced on MCz and FZ wafer of p- and n-type was irradiated in two steps, first by fast charged hadrons followed by reactor neutrons. In this way the irradiations resemble the real irradiation fields at LHC. After irradiations controlled annealing started in steps during which the evolution of full depletion voltage, leakage current and charge collection efficiency was monitored. The damage introduced by different irradiation particles was found to be additive. The most striking consequence of that is a decrease of the full depletion voltage for n-type MCz detectors after additional neutron irradiation. This confirms that effective donors introduced by charged hadron irradiation are compensated by acceptors from neutron irradiation.

  7. Performance of silicon pad detectors after mixed irradiations with neutrons and fast charged hadrons

    International Nuclear Information System (INIS)

    Kramberger, G.; Cindro, V.; Dolenc, I.; Mandic, I.; Mikuz, M.; Zavrtanik, M.

    2009-01-01

    A large set of silicon pad detectors produced on MCz and FZ wafer of p- and n-type was irradiated in two steps, first by fast charged hadrons followed by reactor neutrons. In this way the irradiations resemble the real irradiation fields at LHC. After irradiations controlled annealing started in steps during which the evolution of full depletion voltage, leakage current and charge collection efficiency was monitored. The damage introduced by different irradiation particles was found to be additive. The most striking consequence of that is a decrease of the full depletion voltage for n-type MCz detectors after additional neutron irradiation. This confirms that effective donors introduced by charged hadron irradiation are compensated by acceptors from neutron irradiation.

  8. Reference neutron radiations. Part 2: Calibration fundamentals of radiation protection devices related to the basic quantities characterizing the radiation field

    International Nuclear Information System (INIS)

    2000-01-01

    ISO 8529 consists of the following parts, under the general title Reference neutron radiations: Part 1: Characteristics and methods of production; Part 2: Calibration fundamentals of radiation protection devices related to the basic quantities characterizing the radiation field; Part 3: Calibration of area and personal dosimeters and determination of response as a function of energy and angle of incidence. This Part 2. of ISO 8529 takes as its starting point the neutron sources described in ISO 8529-1. It specifies the procedures to be used for realizing the calibration conditions of radiation protection devices in neutron fields produced by these calibration sources, with particular emphasis on the corrections for extraneous effects (e.g., the neutrons scattered from the walls of the calibration room). In this part of ISO 8529, particular emphasis is placed on calibrations using radionuclide sources (clauses 4 to 6) due to their widespread application, with less details given on the use of accelerator and reactor sources (8.2 and 8.3). This part of ISO 8529 then leads to ISO 8529-3 which gives conversion coefficients and the general rules and procedures for calibration

  9. Neutronic performance of high molecular weight coolants for a prismatic VHTR

    International Nuclear Information System (INIS)

    Schriener, T. M.; El-Genk, M. S.

    2008-01-01

    A neutronic model is developed of a prismatic Very High Temperature Reactor (VHTR) to investigate the effects on the excess reactivity and operation cycle length of replacing helium with binary gas mixtures of He-Ne, He-N 2 , or He-Xe as reactor coolants and working fluids in the direct Closed Brayton Cycle (CBC) for energy conversion. Also investigated is the neutron activation of these binary gas mixtures in the VHTR. The motivation for using the heavy binary mixtures is the smaller size and the fewer number of stages of the CBC turbo-machinery. The present analysis uses the Monte Carlo code MCNPX 2.6D at typical operating conditions (500-1000 degrees and 7.12 MPa) in the VHTR. He-Ne (15 g/mol) is the best neutronically, but not thermal-hydraulically, followed by He-N 2 . Although He-Ne has ∼13.6% lower heat transfer coefficient than helium, it insignificantly affects the initial excess reactivity and the operation life cycle and experiences no neutrons activation. On the other hand, He-N 2 has 4.4% higher heat transfer coefficient than helium and experiences insignificant neutron activation in the reactor, but decreases the initial excess reactivity by ∼5.2% and the operation cycle length by 6.7%. He-Xe (15 g/mol) has 8% higher heat transfer coefficient than helium, but decreases the initial excess reactivity by 18.2% and the operational cycle length by 17%. In addition, neutron activation of xenon produces a significant source term, requiring shielding of the CBC loop and could contaminate the turbo-machinery with long-lived radioactive cesium. Thus, He-Xe is not recommended as a reactor coolant, but could be used as working fluid in a CBC loop that is indirectly coupled to helium cooled VHTR. (authors)

  10. Performance processes within affect-related performance zones: a multi-modal investigation of golf performance.

    Science.gov (United States)

    van der Lei, Harry; Tenenbaum, Gershon

    2012-12-01

    Individual affect-related performance zones (IAPZs) method utilizing Kamata et al. (J Sport Exerc Psychol 24:189-208, 2002) probabilistic model of determining the individual zone of optimal functioning was utilized as idiosyncratic affective patterns during golf performance. To do so, three male golfers of a varsity golf team were observed during three rounds of golf competition. The investigation implemented a multi-modal assessment approach in which the probabilistic relationship between affective states and both, performance process and performance outcome, measures were determined. More specifically, introspective (i.e., verbal reports) and objective (heart rate and respiration rate) measures of arousal were incorporated to examine the relationships between arousal states and both, process components (i.e., routine consistency, timing), and outcome scores related to golf performance. Results revealed distinguishable and idiosyncratic IAPZs associated with physiological and introspective measures for each golfer. The associations between the IAPZs and decision-making or swing/stroke execution were strong and unique for each golfer. Results are elaborated using cognitive and affect-related concepts, and applications for practitioners are provided.

  11. Neutron radiography

    International Nuclear Information System (INIS)

    Bayon, G.

    1989-01-01

    Neutronography or neutron radiography, a non-destructive test method which is similar in its principle to conventional X-ray photography, presently occupies a marginal position among non-destructive test methods (NDT) (no source of suitable performance or cost). Neutron radiography associated with the ORPHEE reactor permits industrial testing; it can very quickly meet a cost requirement comparable to that of conventional test methods. In 1988, 2500 parts were tested on this unit [fr

  12. Experiments on the Biological Actions of Neutrons Performed in the Former Soviet Union: A Historical Review

    Science.gov (United States)

    2006-10-01

    Radio- biologia , 1982, vol. 22, no. 1, pp. 76-81. 10. Bogatyrev A.V., Timoshenko S.I., Lavrova G.A., Nikanorova N.G., Kalmykova G.I., Sverdlov A.G., On...Chernichenko V.A., Cytogenetic Effectiveness of the Therapeutic Fast Neutron Beam Emitted by Cyclotron U-120. Radio- biologia , vol. 24, no. 4, pp. 567-569, 1986...Dependence of Recessive Sex-Linked Lethal Mu- tations in Drosophila Spermatogenesis on Dose from Fast Neutrons. Radio- biologia , v. 2, no. 3, pp. 420-421

  13. Neutron therapy

    International Nuclear Information System (INIS)

    Riesler, Rudi

    1995-01-01

    Standard radiotherapy uses Xrays or electrons which have low LET (linear energy transfer); in contrast, particles such as neutrons with high LET have different radiobiological responses. In the late 1960s, clinical trials by Mary Catterall at the Hammersmith Hospital in London indicated that fast neutron radiation had clinical advantages for certain malignant tumours. Following these early clinical trials, several cyclotron facilities were built in the 1980s for fast neutron therapy, for example at the University of Washington, Seattle, and at UCLA. Most of these newer machines use extracted cyclotron proton beams in the range 42 to 66 MeV with beam intensities of 15 to 60 microamps. The proton beams are transported to dedicated therapy rooms, where neutrons are produced from beryllium targets. Second-generation clinical trials showed that accurate neutron beam delivery to the tumour site is more critical than for photon therapy. In order to achieve precise beam geometries, the extracted proton beams have to be transported through a gantry which can rotate around the patient and deliver beams from any angle; also the neutron beam outline (''field shape'') must be adjusted to extremely irregular shapes using a flexible collimation system. A therapy procedure has to be appropriately organized, with physicians, radiotherapists, nurses, medical physicists and other staff in attendance; other specialized equipment, such as CT or MRI scanners and radiation simulators must be made available. Neutron therapy is usually performed only in radiation oncology departments of major medical centres

  14. Design and performance of high-pressure PLANET beamline at pulsed neutron source at J-PARC

    Energy Technology Data Exchange (ETDEWEB)

    Hattori, T.; Sano-Furukawa, A. [J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Quantum Beam Science Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Arima, H. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Komatsu, K. [Geochemical Research Center, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan); Yamada, A. [University of Shiga Prefecture, Shiga 522-8533 (Japan); Inamura, Y.; Nakatani, T. [J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Seto, Y. [Graduate School of Science, Kobe University, Kobe 657-8501 (Japan); Nagai, T. [Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan); Utsumi, W. [Quantum Beam Science Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Iitaka, T. [Computational Astrophysics Laboratory, RIKEN, Saitama 351-0198 (Japan); Kagi, H. [Geochemical Research Center, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan); Katayama, Y. [Quantum Beam Science Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Inoue, T. [Geodynamic Research Center, Ehime University, Matsuyama 790-8577 (Japan); Otomo, T. [J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 205-001 (Japan); Suzuya, K. [J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Kamiyama, T. [J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 205-001 (Japan); Arai, M. [J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Yagi, T. [Geochemical Research Center, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan)

    2015-04-21

    PLANET is a time-of-flight (ToF) neutron beamline dedicated to high-pressure and high-temperature experiments. The large six-axis multi-anvil high-pressure press designed for ToF neutron diffraction experiments enables routine data collection at high pressures and high temperatures up to 10 GPa and 2000 K, respectively. To obtain clean data, the beamline is equipped with the incident slits and receiving collimators to eliminate parasitic scattering from the high-pressure cell assembly. The high performance of the diffractometer for the resolution (Δd/d~0.6%) and the accessible d-spacing range (0.2–8.4 Å) together with low-parasitic scattering characteristics enables precise structure determination of crystals and liquids under high pressure and temperature conditions.

  15. Design and performance of high-pressure PLANET beamline at pulsed neutron source at J-PARC

    International Nuclear Information System (INIS)

    Hattori, T.; Sano-Furukawa, A.; Arima, H.; Komatsu, K.; Yamada, A.; Inamura, Y.; Nakatani, T.; Seto, Y.; Nagai, T.; Utsumi, W.; Iitaka, T.; Kagi, H.; Katayama, Y.; Inoue, T.; Otomo, T.; Suzuya, K.; Kamiyama, T.; Arai, M.; Yagi, T.

    2015-01-01

    PLANET is a time-of-flight (ToF) neutron beamline dedicated to high-pressure and high-temperature experiments. The large six-axis multi-anvil high-pressure press designed for ToF neutron diffraction experiments enables routine data collection at high pressures and high temperatures up to 10 GPa and 2000 K, respectively. To obtain clean data, the beamline is equipped with the incident slits and receiving collimators to eliminate parasitic scattering from the high-pressure cell assembly. The high performance of the diffractometer for the resolution (Δd/d~0.6%) and the accessible d-spacing range (0.2–8.4 Å) together with low-parasitic scattering characteristics enables precise structure determination of crystals and liquids under high pressure and temperature conditions

  16. Study of the performance of collision short time approximation for neutron scattering using discrete frequency distribution

    International Nuclear Information System (INIS)

    D'Oliveira, A.B.; Amorim, E.S. do; Galvao, O.B.

    1981-03-01

    Double differential cross sections for thermal neutrons, based on incoherent approximation, using continum distribution as discrete frequency set are theoretically estimated, regarding two models previously done. The FASTT computer program is used in order to obtain a numerical estimation. (L.C.) [pt

  17. Performance test of Si PIN photodiode line scanner for thermal neutron detection

    Energy Technology Data Exchange (ETDEWEB)

    Totsuka, Daisuke, E-mail: totsuka@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Nihon Kessho Kogaku Co., Ltd., 810-5 Nobe-cho Tatebayashi, Gunma 374-0047 (Japan); Yanagida, Takayuki [New Industry Creation Hatchery Center (NICHe) 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Fukuda, Kentaro; Kawaguchi, Noriaki [Tokuyama Corp., 3 Shibuya Shibuya-ku, Tokyo 150-8383 (Japan); Fujimoto, Yutaka [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Pejchal, Jan [Institute of Physics AS CR, Cukrovarnicka 10, Prague 6, 162-53 (Czech Republic); Yokota, Yuui [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Yoshikawa, Akira [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); New Industry Creation Hatchery Center (NICHe) 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan)

    2011-12-11

    Thermal neutron imaging using Si PIN photodiode line scanner and Eu-doped LiCaAlF{sub 6} crystal scintillator has been developed. The pixel dimensions of photodiode are 1.18 mm (width) Multiplication-Sign 3.8 mm (length) with 0.4 mm gap and the module has 192 channels in linear array. The emission peaks of Eu-doped LiCaAlF{sub 6} after thermal neutron excitation are placed at 370 and 590 nm, and the corresponding photon sensitivities of photodiode are 0.04 and 0.34 A/W, respectively. Polished scintillator blocks with a size of 1.18 mm (width) Multiplication-Sign 3.8 mm (length) Multiplication-Sign 5.0 mm (thickness) were wrapped by several layers of Teflon tapes as a reflector and optically coupled to the photodiodes by silicone grease. JRR-3 MUSASI beam line emitting 13.5 meV thermal neutrons with the flux of 8 Multiplication-Sign 10{sup 5} n/cm{sup 2} s was used for the imaging test. As a subject for imaging, a Cd plate was moved at the speed of 50 mm/s perpendicular to the thermal neutron beam. Analog integration time was set to be 416.6 {mu}s, then signals were converted by a delta-sigma A/D converter. After the image processing, we successfully obtained moving Cd plate image under thermal neutron irradiation using PIN photodiode line scanner coupled with Eu-doped LiCaAlF{sub 6} scintillator.

  18. Performance test of Si PIN photodiode line scanner for thermal neutron detection

    International Nuclear Information System (INIS)

    Totsuka, Daisuke; Yanagida, Takayuki; Fukuda, Kentaro; Kawaguchi, Noriaki; Fujimoto, Yutaka; Pejchal, Jan; Yokota, Yuui; Yoshikawa, Akira

    2011-01-01

    Thermal neutron imaging using Si PIN photodiode line scanner and Eu-doped LiCaAlF 6 crystal scintillator has been developed. The pixel dimensions of photodiode are 1.18 mm (width)×3.8 mm (length) with 0.4 mm gap and the module has 192 channels in linear array. The emission peaks of Eu-doped LiCaAlF 6 after thermal neutron excitation are placed at 370 and 590 nm, and the corresponding photon sensitivities of photodiode are 0.04 and 0.34 A/W, respectively. Polished scintillator blocks with a size of 1.18 mm (width)×3.8 mm (length)×5.0 mm (thickness) were wrapped by several layers of Teflon tapes as a reflector and optically coupled to the photodiodes by silicone grease. JRR-3 MUSASI beam line emitting 13.5 meV thermal neutrons with the flux of 8×10 5 n/cm 2 s was used for the imaging test. As a subject for imaging, a Cd plate was moved at the speed of 50 mm/s perpendicular to the thermal neutron beam. Analog integration time was set to be 416.6 μs, then signals were converted by a delta-sigma A/D converter. After the image processing, we successfully obtained moving Cd plate image under thermal neutron irradiation using PIN photodiode line scanner coupled with Eu-doped LiCaAlF 6 scintillator.

  19. Evaluation of the fusion-related neutron nuclear data for JENDL-3

    International Nuclear Information System (INIS)

    Chiba, Satoshi

    1988-01-01

    Status of the neutron nuclear data evaluations for JENDL-3 will be described for nuclides important in the development of D-T fusion reactors. In this article, however, only explanation of the evaluations for the very light mass region will be presented to avoid overlapping with what are given in another papers submitted to this seminar. Emphases are placed on the tritium production cross sections, inelastic scattering cross sections including the double-differential neutron emission spectrum (DDX), threshold reaction cross sections and photon production cross sections. The methods employed to prepare JENDL-3T library and their results will be summarized. (author)

  20. Measurement of Relative Biological Effectiveness (RBE) for the Radiation Beam from Neutron Source Reactor YAYOI -Comparisons with Cyclotron Neutron and 60Co Gamma Ray-

    OpenAIRE

    HIROAKI, WAKABAYASHI; SHOZO, SUZUKI; AKIRA, ITO; Nuclear Engineering Research Laboratory, Faculty of Engineering, the University of Tokyo; Institute of Medical Science, the University of Tokyo; Institute of Medical Science, the University of Tokyo

    1983-01-01

    Radiation biology and/or therapy research and development for a research reactor beam need specific RBEs of neutrons as well as of specific reactions. RBEs for reactor beams measured in situ condition are interesting because actual radiation effects on each biological system are different depending on detailed conditions of irradiation. A small powered research reactor (Fast Neutron Source Reactor: YAYOI) was examined here as a neutron beam source for obtaining survival curves in a manner usu...

  1. Relative biological effectiveness (RBE) of fission neutrons and gamma rays at occupational exposure levels: Volume 1, Studies on the genetic effects in mice of 60 equal once-weekly exposures to fission neutrons and gamma rays

    International Nuclear Information System (INIS)

    Grahn, D.; Carnes, B.A.

    1987-10-01

    The relative biological effectiveness (RBE) values for low doses of fission neutrons compared to 60 Co gamma rays were determined with four separate assessments of genetic damage induced in young hybrid male mice. Both radiations were delivered at low dose levels over about one-half the adult lifetime as 60 once-weekly exposures. Genetic damage assessed included both transient and residual injury. The latter is more critical, as residual genetic injury can be transmitted to subsequent generations long after the radiation exposures have ceased. Assays were performed periodically during the 60-week exposure period and at 10 or more weeks after the irradiations had terminated. RBE values, with few exceptions, ranged between 5 and 15 for transient injury and between 25 and 50 for different types of residual genetic injury. The most important form of residual genetic damage in this study was the balanced reciprocal chromosome translocation. These translocations continue to be transmitted throughout reproductive life and can lead to reduced fertility and increased prenatal mortality. The best estimate of the RBE value for translocations was 45 +- 10. Implications and recommendations with regard to the neutron quality factor will be presented conjointly with the findings from the data obtained in this same project on life shortening and on the risks of incidence or death from neoplastic disease. 64 refs., 23 tabs

  2. Relating FTS Catalyst Properties to Performance

    Science.gov (United States)

    Ma, Wenping; Ramana Rao Pendyala, Venkat; Gao, Pei; Jermwongratanachai, Thani; Jacobs, Gary; Davis, Burton H.

    2016-01-01

    During the reporting period June 23, 2011 to August 31, 2013, CAER researchers carried out research in two areas of fundamental importance to the topic of cobalt-based Fischer-Tropsch Synthesis (FTS): promoters and stability. The first area was research into possible substitute promoters that might be used to replace the expensive promoters (e.g., Pt, Re, and Ru) that are commonly used. To that end, three separate investigations were carried out. Due to the strong support interaction of ?-Al2O3 with cobalt, metal promoters are commonly added to commercial FTS catalysts to facilitate the reduction of cobalt oxides and thereby boost active surface cobalt metal sites. To date, the metal promoters examined have been those up to and including Group 11. Because two Group 11 promoters (i.e., Ag and Au) were identified to exhibit positive impacts on conversion, selectivity, or both, research was undertaken to explore metals in Groups 12 - 14. The three metals selected for this purpose were Cd, In, and Sn. At a higher loading of 25%Co on alumina, 1% addition of Cd, In, or Sn was found to-on average-facilitate reduction by promoting a heterogeneous distribution of cobalt consisting of larger lesser interacting cobalt clusters and smaller strongly interacting cobalt species. The lesser interacting species were identified in TPR profiles, where a sharp low temperature peak occurred for the reduction of larger, weakly interacting, CoO species. In XANES, the Cd, In, and Sn promoters were found to exist as oxides, whereas typical promoters (e.g., Re, Ru, Pt) were previously determined to exist in an metallic state in atomic coordination with cobalt. The larger cobalt clusters significantly decreased the active site density relative to the unpromoted 25%Co/Al2O3 catalyst. Decreasing the cobalt loading to 15%Co eliminated the large non-interacting species. The TPR peak for reduction of strongly interacting CoO in the Cd promoted catalyst occurred at a measurably lower temperature

  3. Neutron detection in the frame of spatial magnetic spin resonance

    Energy Technology Data Exchange (ETDEWEB)

    Jericha, Erwin, E-mail: jericha@ati.ac.at [TU Wien, Atominstitut, Stadionallee 2, 1020 Wien (Austria); Bosina, Joachim [TU Wien, Atominstitut, Stadionallee 2, 1020 Wien (Austria); Austrian Academy of Sciences, Stefan Meyer Institute, Boltzmanngasse 3, 1090 Wien (Austria); Institut Laue–Langevin, 71 Avenue des Martyrs, 38042 Grenoble (France); Geltenbort, Peter [Institut Laue–Langevin, 71 Avenue des Martyrs, 38042 Grenoble (France); Hino, Masahiro [Kyoto University, Research Reactor Institute, Kumatori, Osaka 590-0494 (Japan); Mach, Wilfried [TU Wien, Atominstitut, Stadionallee 2, 1020 Wien (Austria); Oda, Tatsuro [Kyoto University, Department of Nuclear Engineering, Kyoto 615-8540 (Japan); Badurek, Gerald [TU Wien, Atominstitut, Stadionallee 2, 1020 Wien (Austria)

    2017-02-11

    This work is related to neutron detection in the context of the polarised neutron optics technique of spatial magnetic spin resonance. By this technique neutron beams may be tailored in their spectral distribution and temporal structure. We have performed experiments with very cold neutrons (VCN) at the high-flux research reactor of the Institut Laue Langevin (ILL) in Grenoble to demonstrate the potential of this method. A combination of spatially and temporally resolving neutron detection allowed us to characterize a prototype neutron resonator. With this detector we were able to record neutron time-of-flight spectra, assess and minimise neutron background and provide for normalisation of the spectra owing to variations in reactor power and ambient conditions at the same time.

  4. Performance characteristics of a prompt gamma-ray activation analysis (PGAA) system equipped with a new compact D-D neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yong Joon; Song, Byung Chul; Im, Hee-Jung [Nuclear Chemistry Research Division, Korea Atomic Energy Research Institute, Dukjin-dong 150-1, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Kim, Jong-Yun [Nuclear Chemistry Research Division, Korea Atomic Energy Research Institute, Dukjin-dong 150-1, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)], E-mail: kjy@kaeri.re.kr

    2009-07-21

    A new prompt gamma-ray activation analysis (PGAA) system equipped with a compact deuterium-deuterium (D-D) neutron generator has been developed for fast detection of explosives and chemical warfare agents. The PGAA system was built based on a fully high-voltage-shielded, axial D-D neutron generator with a radio frequency (RF)-driven ion source. The ionic current of the compact neutron generator was determined as a function of the acceleration voltage at various RF powers. Monoenergetic neutrons (2.45 MeV) with a neutron yield of >1x10{sup 7} n/s were obtained at a deuterium pressure of 8.0 mTorr, an acceleration voltage of 80 kV, and an RF power of 1.1 kW. The performance of the PGAA system was examined by studying the dependence of a prompt gamma-ray count rate on crucial operating parameters.

  5. Prospects for neutron-antineutron transition search

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  6. Neutron scattering in Indonesia. Country report

    Energy Technology Data Exchange (ETDEWEB)

    Ikram, Abarrul [Neutron Scattering Laboratory, R and D Center for Materials Science and Technology, National Nuclear Energy Agency, Serpong (Indonesia)

    2000-10-01

    Neutron scattering in Indonesia is still alienated due to some reasons and conditions which are discussed. The reactor and its latest operation mode are also described. The neutron beam facilities which include one diffractometer for residual stress measurement, one diffractometer for single crystal structural determination and texture measurement, one high resolution powder diffractometer, one neutron radiography facility, one triple axis spectrometer, one small angle neutron scattering spectrometer and one high resolution small angle neutron scattering spectrometer were presented briefly together with improvements of neutron intensities at some spectrometers in connection with the setting of main beam shutter position. Special attention is given for four instruments mostly related to this workshop. Their performances and problems faced in the past 9 months are presented as well as the future plan for refurbishment and development. (author)

  7. Textures of iron oxide ores by neutron diffraction and topotactical relation

    International Nuclear Information System (INIS)

    Wagner, F.; Esling, C.; Baro, R.; Englander, M.

    1977-01-01

    Two samples are cut from a polycrystalline haematite block. The first one is directly submitted to texture analysis by neutron diffraction, whereas the second one is first reduced into magnetite. The comparison of both textures is in agreement with a topotactical relationship previously reported for monocrystals. (orig.) [de

  8. Relative biological effectiveness (RBE) of fast neutrons with the Dunning rat prostate tumor R3327-HI

    International Nuclear Information System (INIS)

    Wenz, F.; Lohr, F.; Peschke, P.; Wolber, G.; Hoever, K.H.; Hahn, E.W.

    1993-01-01

    Human prostate tumors are known to be good candidates for neutron therapy. The Dunning rat prostate tumor system R3327 was found in many studies to be an excellent model for human prostate tumors. There is still a paucity of studies on the response of the Dunning tumors to fast neutrons. Tumors of the R3327-HI subline are moderately well differentiated and mucin producing. They show one euploid cell population, a bromodeoxyuridine labelling index of 5%, a potential doubling time of 8.9 days, a volume doubling time of about ten days and a cell loss rate of 10%. Tumors were transplanted s.c. in the distal thigh of Copenhagen rats and treated with 60 Co-photons (10, 20, 30, 40 Gy, 45 cGy/min) and 14-MeV-neutrons (8, 10, 12 Gy, 7 to 11 cGy/min). Tumor volumes were measured twice weekly. Growth delay was defined as time in days until the tumors reached twice their treatment volume. Linear regressions on the median growth delays of the different treatment groups were calculated. The ratio of the neutron- and photon-slopes yielded an RBE of 3.1±0.3. Additionally isoeffect-RBE values between 2.3 and 2.6 were graphically estimated. (orig.) [de

  9. FENDL-3 benchmark test with neutronics experiments related to fusion in Japan

    International Nuclear Information System (INIS)

    Konno, Chikara; Ohta, Masayuki; Takakura, Kosuke; Ochiai, Kentaro; Sato, Satoshi

    2014-01-01

    Highlights: •We have benchmarked FENDL-3.0 with integral experiments with DT neutron sources in Japan. •The FENDL-3.0 is as accurate as FENDL-2.1 and JENDL-4.0 or more. •Some data in FENDL-3.0 may have some problems. -- Abstract: The IAEA supports and promotes the gathering of the best data from evaluated nuclear data libraries for each nucleus involved in fusion reactor applications and compiles these data as FENDL. In 2012, the IAEA released a major update to FENDL, FENDL-3.0, which extends the neutron energy range from 20 MeV to greater than 60 MeV for 180 nuclei. We have benchmarked FENDL-3.0 versus in situ and TOF experiments using the DT neutron source at FNS at the JAEA and TOF experiments using the DT neutron source at OKTAVIAN at Osaka University in Japan. The Monte Carlo code MCNP-5 and the ACE file of FENDL-3.0 supplied from the IAEA were used for the calculations. The results were compared with measured ones and those obtained using the previous version, FENDL-2.1, and the latest version, JENDL-4.0. It is concluded that FENDL-3.0 is as accurate as or more so than FENDL-2.1 and JENDL-4.0, although some data in FENDL-3.0 may be problematic

  10. Moment of inertia, quadrupole moment, Love number of neutron star and their relations with strange-matter equations of state

    Science.gov (United States)

    Bandyopadhyay, Debades; Bhat, Sajad A.; Char, Prasanta; Chatterjee, Debarati

    2018-02-01

    We investigate the impact of strange-matter equations of state involving Λ hyperons, Bose-Einstein condensate of K- mesons and first-order hadron-quark phase transition on moment of inertia, quadrupole moment and tidal deformability parameter of slowly rotating neutron stars. All these equations of state are compatible with the 2 M_{solar} constraint. The main findings of this investigation are the universality of the I- Q and I -Love number relations, which are preserved by the EoSs including Λ hyperons and antikaon condensates, but broken in the presence of a first-order hadron-quark phase transition. Furthermore, it is also noted that the quadrupole moment approaches the Kerr value of a black hole for maximum-mass neutron stars.

  11. Calibration issues for neutron diagnostics

    International Nuclear Information System (INIS)

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

    1997-01-01

    The performance of diagnostic systems are limited by their weakest constituents, including their calibration issues. Neutron diagnostics are notorious for problems encountered while determining their absolute calibrations, due mainly to the nature of the neutron transport problem. In order to facilitate the determination of an accurate and precise calibration, the diagnostic design should be such as to minimize the scattered neutron flux. ITER will use a comprehensive set of neutron diagnostics--comprising radial and vertical neutron cameras, neutron spectrometers, a neutron activation system and internal and external fission chambers--to provide accurate measurements of fusion power and power densities as a function of time. The calibration of such an important diagnostic system merits careful consideration. Some thoughts have already been given to this subject during the conceptual design phase in relation to the time-integrated neutron activation and time-dependent neutron yield monitors. However, no overall calibration strategy has been worked out so far. This paper represents a first attempt to address this vital issue. Experience gained from present large tokamaks (JET, TFTR and JT60U) and proposals for ITER are reviewed. The need to use a 14-MeV neutron generator as opposed to radioactive sources for in-situ calibration of D-T diagnostics will be stressed. It is clear that the overall absolute determination of fusion power will have to rely on a combination of nuclear measuring techniques, for which the provision of accurate and independent calibrations will constitute an ongoing process as ITER moves from one phase of operation to the next

  12. Performance of a parallel algorithm for solving the neutron diffusion equation on the hypercube

    International Nuclear Information System (INIS)

    Kirk, B.L.; Azmy, Y.Y.

    1989-01-01

    The one-group, steady state neutron diffusion equation in two- dimensional Cartesian geometry is solved using the nodal method technique. By decoupling sets of equations representing the neutron current continuity along the length of rows and columns of computational cells a new iterative algorithm is derived that is more suitable to solving large practical problems. This algorithm is highly parallelizable and is implemented on the Intel iPSC/2 hypercube in three versions which differ essentially in the total size of communicated data. Even though speedup was achieved, the efficiency is very low when many processors are used leading to the conclusion that the hypercube is not as well suited for this algorithm as shared memory machines. 10 refs., 1 fig., 3 tabs

  13. Neutronics of pulsed spallation neutron sources

    International Nuclear Information System (INIS)

    Watanabe, Noboru

    2003-01-01

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

  14. Performance of the prototype LANL solid deuterium ultra-cold neutron source

    CERN Document Server

    Hill, R E; Bowles, T J; Greene, G L; Hogan, G; Lamoreaux, S; Marek, L; Mortenson, R; Morris, C L; Saunders, A; Seestrom, S J; Teasdale, W A; Hoedl, S; Liu, C Y; Smith, D A; Young, A; Filippone, B W; Hua, J; Ito, T; Pasyuk, E A; Geltenbort, P; García, A; Fujikawa, B; Baessler, S; Serebrov, A

    2000-01-01

    A prototype of a solid deuterium (SD sub 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 ( sup 5 sup 8 Ni). The rates and time-of-flight data from this detector are compared with calculated values. Measurements of UCN production as a function of SD sub 2 volume (thickness) are compared with predicted values. The dependence of UCN production on SD sub 2 temperature and proton beam...

  15. Enhancing the performances of a resonance detector spectrometer for deep inelastic neutron scattering measurements

    International Nuclear Information System (INIS)

    Filabozzi, A.; Pace, E.; Pietropaolo, A.

    2012-01-01

    The possibility is explored to sum up neutron Compton profiles at different scattering angles in deep inelastic neutron scattering measurements within the Resonance Detector (RD) configuration to enhance the statistics for a more reliable extraction of the momentum distribution of the constituents in the target. The RD configuration allows to select the energy of the scattered neutrons up to several tens of electron Volt, thus accessing energy and wave vector transfers well above 1 eV and 30 Å −1 , respectively. In the high-q/ω regime, the final state effects could be considered as negligible, as shown in a series of simulations using a Monte Carlo method with different inverse geometry instrument setups. The simulations show that it could be possible to conceive an instrument set up where the RD configuration allows the proper summation of several spectra at different scattering angles, providing a good separation of the proton recoil signal from that of the heavier atoms, thus avoiding the cell subtraction by fitting procedure.

  16. A development and integration of the concentration database for relative method, k0 method and absolute method in instrumental neutron activation analysis using Microsoft Access

    International Nuclear Information System (INIS)

    Hoh Siew Sin

    2012-01-01

    Instrumental Neutron Activation Analysis (INAA) is offen used to determine and calculate the concentration of an element in the sample by the National University of Malaysia, especially students of Nuclear Science Program. The lack of a database service leads consumers to take longer time to calculate the concentration of an element in the sample. This is because we are more dependent on software that is developed by foreign researchers which are costly. To overcome this problem, a study has been carried out to build an INAA database software. The objective of this study is to build a database software that help the users of INAA in Relative Method and Absolute Method for calculating the element concentration in the sample using Microsoft Excel 2010 and Microsoft Access 2010. The study also integrates k 0 data, k 0 Concent and k 0 -Westcott to execute and complete the system. After the integration, a study was conducted to test the effectiveness of the database software by comparing the concentrations between the experiments and in the database. Triple Bare Monitor Zr-Au and Cr-Mo-Au were used in Abs-INAA as monitor to determine the thermal to epithermal neutron flux ratio (f). Calculations involved in determining the concentration are the net peak area (N p ), the measurement time (t m ), the irradiation time (t irr ), k-factor (k), thermal to epithermal neutron flux ratio (f), the parameters of the neutron flux distribution epithermal (α) and detection efficiency (ε p ). For Com-INAA databases, reference material IAEA-375 Soil was used to calculate the concentration of elements in the sample. CRM, SRM are also used in this database. After the INAA database integration, a verification process was to examine the effectiveness of the Abs-INAA was carried out by comparing the sample concentration between the in database and the experiment. The result of the experimental concentration value of INAA database software performed with high accuracy and precision. ICC

  17. Very slow neutrons

    International Nuclear Information System (INIS)

    Frank, A.

    1983-01-01

    The history is briefly presented of the research so far of very slow neutrons and their basic properties are explained. The methods are described of obtaining very slow neutrons and the problems of their preservation are discussed. The existence of very slow neutrons makes it possible to perform experiments which may deepen the knowledge of the fundamental properties of neutrons. Their wavelength approximates that of visible radiation. The possibilities and use are discussed of neutron optical systems (neutron microscope) which could be an effective instrument for the study of the detailed arrangement, especially of organic substances. (B.S.)

  18. The Dilemmas of Adopting Performance Related Pay as a Reward ...

    African Journals Online (AJOL)

    The Dilemmas of Adopting Performance Related Pay as a Reward Strategy for ... over automatic pay increase (formal and transparent reward systems linked to ... of reward and compensation, and low level of motivation and performance.

  19. Neutron Scattering

    International Nuclear Information System (INIS)

    Fayer, Michael J.; Gee, Glendon W.

    2005-01-01

    The neutron probe is a standard tool for measuring soil water content. This article provides an overview of the underlying theory, describes the methodology for its calibration and use, discusses example applications, and identifies the safety issues. Soil water makes land-based life possible by satisfying plant water requirements, serving as a medium for nutrient movement to plant roots and nutrient cycling, and controlling the fate and transport of contaminants in the soil environment. Therefore, a successful understanding of the dynamics of plant growth, nutrient cycling, and contaminant behavior in the soil requires knowledge of the soil water content as well as its spatial and temporal variability. After more than 50 years, neutron probes remain the most reliable tool available for field monitoring of soil water content. Neutron probes provide integrated measurements over relatively large volumes of soil and, with proper access, allow for repeated sampling of the subsurface at the same locations. The limitations of neutron probes include costly and time-consuming manual operation, lack of data automation, and costly regulatory requirements. As more non-radioactive systems for soil water monitoring are developed to provide automated profiling capabilities, neutron-probe usage will likely decrease. Until then, neutron probes will continue to be a standard for reliable measurements of field water contents in soils around the globe

  20. Use and imaging performance of CMOS flat panel imager with LiF/ZnS(Ag) and Gadox scintillation screens for neutron radiography

    Science.gov (United States)

    Cha, B. K.; kim, J. Y.; Kim, T. J.; Sim, C.; Cho, G.; Lee, D. H.; Seo, C.-W.; Jeon, S.; Huh, Y.

    2011-01-01

    In digital neutron radiography system, a thermal neutron imaging detector based on neutron-sensitive scintillating screens with CMOS(complementary metal oxide semiconductor) flat panel imager is introduced for non-destructive testing (NDT) application. Recently, large area CMOS APS (active-pixel sensor) in conjunction with scintillation films has been widely used in many digital X-ray imaging applications. Instead of typical imaging detectors such as image plates, cooled-CCD cameras and amorphous silicon flat panel detectors in combination with scintillation screens, we tried to apply a scintillator-based CMOS APS to neutron imaging detection systems for high resolution neutron radiography. In this work, two major Gd2O2S:Tb and 6LiF/ZnS:Ag scintillation screens with various thickness were fabricated by a screen printing method. These neutron converter screens consist of a dispersion of Gd2O2S:Tb and 6LiF/ZnS:Ag scintillating particles in acrylic binder. These scintillating screens coupled-CMOS flat panel imager with 25x50mm2 active area and 48μm pixel pitch was used for neutron radiography. Thermal neutron flux with 6x106n/cm2/s was utilized at the NRF facility of HANARO in KAERI. The neutron imaging characterization of the used detector was investigated in terms of relative light output, linearity and spatial resolution in detail. The experimental results of scintillating screen-based CMOS flat panel detectors demonstrate possibility of high sensitive and high spatial resolution imaging in neutron radiography system.

  1. Survey of trace elements in coals and coal-related materials by neutron activation analysis

    International Nuclear Information System (INIS)

    Ruch, R.R.; Cahill, R.A.; Frost, J.K.; Camp, L.R.; Gluskoter, H.J.

    1977-01-01

    Utilizing primarily instrumental neutron activation analysis and other analytical methods such as neutron-activation analysis with radiochemical separation, emission spectrochemical analysis, atomic absorption spectroscopy, X-ray fluorescence analysis, ion-selective electrode analysis, and American Society for Testing of Materials procedures (ASTM), as many as 61 elements were quantitatively surveyed in 170 U.S. whole coals, 70 washed coals, and 40 bench samples. Data on areal and vertical distributions in various regions were obtained along with extensive information on the mode of occurence of various elements in the coal matrix itself. Efforts have been made to attain the maximal accuracy and precision possible for a wide variety of elements in the inhomogeneous coal matrix. (T.G.)

  2. The comparison of four neutron sources for Prompt Gamma Neutron Activation Analysis (PGNAA) in vivo detections of boron.

    Science.gov (United States)

    Fantidis, J G; Nicolaou, G E; Potolias, C; Vordos, N; Bandekas, D V

    A Prompt Gamma Ray Neutron Activation Analysis (PGNAA) system, incorporating an isotopic neutron source has been simulated using the MCNPX Monte Carlo code. In order to improve the signal to noise ratio different collimators and a filter were placed between the neutron source and the object. The effect of the positioning of the neutron beam and the detector relative to the object has been studied. In this work the optimisation procedure is demonstrated for boron. Monte Carlo calculations were carried out to compare the performance of the proposed PGNAA system using four different neutron sources ( 241 Am/Be, 252 Cf, 241 Am/B, and DT neutron generator). Among the different systems the 252 Cf neutron based PGNAA system has the best performance.

  3. Instrumental neutron activation analysis of human hair and related radiotracer experiments on washing and leaching

    International Nuclear Information System (INIS)

    Das, H.A.; Hoede, D.; Sloot, H.A. van der; Herber, R.F.M.

    1981-11-01

    The work done under the IAEA-contract 2440/RB is summarized. The aim was to develop a fast and reliable system for the determination of tracer elements in human head hair by instrumental neutron activation analysis (INAA) and radiotracer washing experiments. The standardized procedure for INAA was applied to hair samples collected by the Coronel Laboratory of the University of Amsterdam. The correlation between trace element contents is considered

  4. Investigation of magnon dispersion relations and neutron scattering cross sections with special attention to anisotropy effects

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker; Kowalska, A.; Laut, Peter

    1967-01-01

    curves are suggested. The magnon cross section for unpolarized neutrons is calculated and shown to be dependent on the anisotropy in the spin interaction. Thus in principle it allows the detection of anisotropy in the exchange interaction. Some remarks are made concerning antiferromagnetic and plane...... for the exchange interaction seem to be necessary for agreement with experimental dispersion curves be obtained. The effect of the anisotropy in the cross section is estimated and shown to be important for small magnon energies....

  5. Neutron in biology

    Energy Technology Data Exchange (ETDEWEB)

    Niimura, Nobuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-11-01

    Neutron in biology can provide an experimental method of directly locating relationship of proteins and DNA. However, there are relatively few experimental study of such objects since it takes a lot of time to collect a sufficient number of Bragg reflections and inelastic spectra due to the low flux of neutron illuminating the sample. Since a next generation neutron source of JAERI will be 5MW spallation neutron source and its effective neutron flux will be 10{sup 2} to 10{sup 3} times higher than the one of JRR-3M, neutron in biology will open a completely new world for structural biology. (author)

  6. Layered semiconductor neutron detectors

    Science.gov (United States)

    Mao, Samuel S; Perry, Dale L

    2013-12-10

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

  7. Neutron in biology

    International Nuclear Information System (INIS)

    Niimura, Nobuo

    1997-01-01

    Neutron in biology can provide an experimental method of directly locating relationship of proteins and DNA. However, there are relatively few experimental study of such objects since it takes a lot of time to collect a sufficient number of Bragg reflections and inelastic spectra due to the low flux of neutron illuminating the sample. Since a next generation neutron source of JAERI will be 5MW spallation neutron source and its effective neutron flux will be 10 2 to 10 3 times higher than the one of JRR-3M, neutron in biology will open a completely new world for structural biology. (author)

  8. The coupling of the neutron transport application RATTLESNAKE to the nuclear fuels performance application BISON under the MOOSE framework

    Energy Technology Data Exchange (ETDEWEB)

    Gleicher, Frederick N.; Williamson, Richard L.; Ortensi, Javier; Wang, Yaqi; Spencer, Benjamin W.; Novascone, Stephen R.; Hales, Jason D.; Martineau, Richard C.

    2014-10-01

    The MOOSE neutron transport application RATTLESNAKE was coupled to the fuels performance application BISON to provide a higher fidelity tool for fuel performance simulation. This project is motivated by the desire to couple a high fidelity core analysis program (based on the self-adjoint angular flux equations) to a high fidelity fuel performance program, both of which can simulate on unstructured meshes. RATTLESNAKE solves self-adjoint angular flux transport equation and provides a sub-pin level resolution of the multigroup neutron flux with resonance treatment during burnup or a fast transient. BISON solves the coupled thermomechanical equations for the fuel on a sub-millimeter scale. Both applications are able to solve their respective systems on aligned and unaligned unstructured finite element meshes. The power density and local burnup was transferred from RATTLESNAKE to BISON with the MOOSE Multiapp transfer system. Multiple depletion cases were run with one-way data transfer from RATTLESNAKE to BISON. The eigenvalues are shown to agree well with values obtained from the lattice physics code DRAGON. The one-way data transfer of power density is shown to agree with the power density obtained from an internal Lassman-style model in BISON.

  9. Evaluation of the dark signal performance of different SiPM-technologies under irradiation with cold neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Durini, Daniel, E-mail: d.durini@fz-juelich.de [Central Institute of Engineering, Electronics and Analytics ZEA-2 – Electronic Systems, Forschungszentrum Jülich GmbH, D-52425 Jülich (Germany); Degenhardt, Carsten; Rongen, Heinz [Central Institute of Engineering, Electronics and Analytics ZEA-2 – Electronic Systems, Forschungszentrum Jülich GmbH, D-52425 Jülich (Germany); Feoktystov, Artem [Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, D-85748 Garching (Germany); Schlösser, Mario; Palomino-Razo, Alejandro [Central Institute of Engineering, Electronics and Analytics ZEA-2 – Electronic Systems, Forschungszentrum Jülich GmbH, D-52425 Jülich (Germany); Frielinghaus, Henrich [Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, D-85748 Garching (Germany); Waasen, Stefan van [Central Institute of Engineering, Electronics and Analytics ZEA-2 – Electronic Systems, Forschungszentrum Jülich GmbH, D-52425 Jülich (Germany)

    2016-11-01

    In this paper we report the results of the assessment of changes in the dark signal delivered by three silicon photomultiplier (SiPM) detector arrays, fabricated by three different manufacturers, when irradiated with cold neutrons (wavelength λ{sub n}=5 Å or neutron energy of E{sub n}=3.27 meV) up to a neutron dose of 6×10{sup 12} n/cm{sup 2}. The dark signals as well as the breakdown voltages (V{sub br}) of the SiPM detectors were monitored during the irradiation. The system was characterized at room temperature. The analog SiPM detectors, with and without a 1 mm thick Cerium doped {sup 6}Li-glass scintillator material located in front of them, were operated using a bias voltage recommended by the respective manufacturer for a proper detector performance. I{sub out}-V{sub bias} measurements, used to determine the breakdown voltage of the devices, were repeated every 30 s during the first hour and every 300 s during the rest of the irradiation time. The digital SiPM detectors were held at the advised bias voltage between the respective breakdown voltage and dark count mappings repeated every 4 min. The measurements were performed on the KWS-1 instrument of the Heinz Maier-Leibnitz Zentrum (MLZ) in Garching, Germany. The two analog and one digital SiPM detector modules under investigation were respectively fabricated by SensL (Ireland), Hamamatsu Photonics (Japan), and Philips Digital Photon Counting (Germany).

  10. Neutron magnetic scattering experiments performed by VIKRA group at the RA reactor in Vinca; Eksperimenti grupe VIKRA na reaktoru RA u Vinci sa rasejanjem neutrona na magnetnim materijalima

    Energy Technology Data Exchange (ETDEWEB)

    Kranicki, S; Rzany, H; Wanic, A [Institute of Nuclear Physics, Krakov (Poland); Szytula, A [Jagiellonian University, Krakov (Poland); Todorovic, J; Dimitrijevic, Z; Radenkovic, S [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

    1978-05-15

    A short communication about investigations of magnetic materials by means of the neutron magnetic scattering performed by Polish-Yugoslav group VIKRA (Vinca-Krakov) at the RA reactor in Vinca in the period 1962-1977 will be presented. In the field of neutron inelastic scattering information about magnetic interactions (exchange integrals) and their temperature behaviour in such substances as Fe{sub 7}S{sub 8}, {alpha}-Fe{sub 2}O{sub 3}, CR{sub 2}O{sub 3}, {alpha}-Co, Cu{sub 2}MnAl and Mn{sub 1.88}Cr{sub 0.12}Sb was obtained by measuring magnon dispersion relations. In the field of neutron elastic scattering valuable results concerning crystallographic and magnetic structures of oxyhydroxides, several Heusler alloys and intermetallic compounds of 3d metals (for instance of NiMnGe, CoMnSi) were obtained. A short description of the KSN spectrometer used in all experiments will also be given. (author) Dato je kratko saopstenje o istrazivanjima magnetnih materijala magnetnim neutronskim rasejanjem izvrsenim od strane poljsko-jugoslovenske grupe VIKRA (Vinca-Krakov) na reaktoru RA u Vinci u periodu od 1962-1977. U oblasti neelasticnog rasejanja neutrona, obavestenja o magnetnim uzajamnim dejstvima (integralima izmene) i njihovim temperaturskim ponasanjima su dobijeni merenjem disperzione relacije magnona u takvim materijalima kao sto su Fe{sub 7}S{sub 8}, {alpha}-Fe{sub 2}O{sub 3}, CR{sub 2}O{sub 3}, {alpha}-Co, Cu{sub 2}MnAl and Mn{sub 1.88}Cr{sub 0.12}Sb. U oblasti neutronskog elasticnog rasejanja dobijeni su korisni rezultati o kristalografskim i magnetnim strukturama oksihidroksida gvozdja, niza Heuslerovih legura i intermetalnih jedinjenja 3d metala (napr. NiMnGe, Co,MnSi). Dat je kratak opis KSN spektrometra upotrebljenog u svim ovim eksperimentima. (author)

  11. Study of variation of materials patients room's door related of neutron flux iradiation

    Science.gov (United States)

    Nirmalasari, Yuliana Dian; Suparmi, A.; Sardjono, Y.

    2017-08-01

    The treatment chamber of patients has been simulating with MCNPX Code. Optimation of simulation design of Irradiation chamber is corresponding to ISO standards for 30 MeV cyclotron generator. The simulation has used the variation of door's materials that was applied at treatment room's door. The variation of materials was Stainless Steel 202 and Pb, the thickness Pb and stainless steel 202 with the thickness were 2 cm, respectively. Neutron flux that was radiated to stainless steel 202 in the sequence was 3.34195 × 105 n . Cm-2 s-1 and 8.41568 × 104 n . Cm-2 s-1, while for Pb was 4.01349 × 105 n . Cm-2 s-1 and 2.58058 × 104 n . Cm-2 s-1. The further, neutron flux that was radiated to Pb and stainless steel 202 with the thickness were 4 cm in sequence was 4.00601 × 105 n . Cm-2 s-1 and 1.71713 × 104 n . Cm-2 s-1 for Pb, while for SS 202 was 3.09925 × 105 n . Cm-2 s-1. From this ratio we concluded that material Pb absorbed higher neutron flux than material Stainless Steel 202. On the other hand, the cost of Pb was more expensive than Stainless Steel 202. In addition, the material Stainless Steel 202 was obtaine more easily than the material Pb. There fore to overcome the economics problem, can try to build the door with stainless still 202 sheet and Pb sheet together. The further, the neutron dose with 2 cm of thickness was 7.69603 × 10-2 Gy and 2.10623 × 10-2 Gy for SS 202, while for Pb was 4.19444 × 10-2 Gy and 1.50581 × 10-2 Gy. While the neutron dose with 4 cm of thickness for SS 202 was 9.39602 × 10-2 Gy and for Pb was 4.46541 × 10-2 Gy and 1.50502 × 10-2 Gy. We recommend that this simulation should be further optimized.

  12. Measuring neutron spectra in radiotherapy using the nested neutron spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Maglieri, Robert, E-mail: robert.maglieri@mail.mcgill.ca; Evans, Michael; Seuntjens, Jan; Kildea, John [Medical Physics Unit, McGill University, Montreal, Quebec H4A 3J1 (Canada); Licea, Angel [Canadian Nuclear Safety Commission, Ottawa, Ontario K1P 5S9 (Canada)

    2015-11-15

    Purpose: Out-of-field neutron doses resulting from photonuclear interactions in the head of a linear accelerator pose an iatrogenic risk to patients and an occupational risk to personnel during radiotherapy. To quantify neutron production, in-room measurements have traditionally been carried out using Bonner sphere systems (BSS) with activation foils and TLDs. In this work, a recently developed active detector, the nested neutron spectrometer (NNS), was tested in radiotherapy bunkers. Methods: The NNS is designed for easy handling and is more practical than the traditional BSS. Operated in current-mode, the problem of pulse pileup due to high dose-rates is overcome by measuring current, similar to an ionization chamber. In a bunker housing a Varian Clinac 21EX, the performance of the NNS was evaluated in terms of reproducibility, linearity, and dose-rate effects. Using a custom maximum-likelihood expectation–maximization algorithm, measured neutron spectra at various locations inside the bunker were then compared to Monte Carlo simulations of an identical setup. In terms of dose, neutron ambient dose equivalents were calculated from the measured spectra and compared to bubble detector neutron dose equivalent measurements. Results: The NNS-measured spectra for neutrons at various locations in a treatment room were found to be consistent with expectations for both relative shape and absolute magnitude. Neutron fluence-rate decreased with distance from the source and the shape of the spectrum changed from a dominant fast neutron peak near the Linac head to a dominant thermal neutron peak in the moderating conditions of the maze. Monte Carlo data and NNS-measured spectra agreed within 30% at all locations except in the maze where the deviation was a maximum of 40%. Neutron ambient dose equivalents calculated from the authors’ measured spectra were consistent (one standard deviation) with bubble detector measurements in the treatment room. Conclusions: The NNS may

  13. Developmental testing of partially volatile neutron shields for high-performance shipping casks

    International Nuclear Information System (INIS)

    Pope, R.B.; Allen, G.C.; Rack, H.J.; Joseph, B.J.; Dupree, S.A.

    1980-01-01

    Results of the phase one tests have demonstrated that the neutron-shielding concept described in this paper is a viable design option for spent fuel shipping casks. The tests have shown that the Boro-silicone 236 shield is superior to the other shield materials considered. Repeated TGA, aging and fire tests demonstrated the reliability of the data. A second phase of the test program is now being pursued where the Boro-silicone 236 is injected into all-steel slab sections, and cured in place. 5 tables

  14. Performance of neutron activation analysis in the evaluation of bismuth iodide purification methodology

    International Nuclear Information System (INIS)

    Armelin, Maria Jose A.; Ferraz, Caue de Mello; Hamada, Margarida M.

    2015-01-01

    Bismuth tri-iodide (BrI 3 ) is an attractive material for using as a semiconductor. In this paper, BiI 3 crystals have been grown by the vertical Bridgman technique using commercially available powder. The impurities were evaluated by instrumental neutron activation analysis (INAA). The results show that INAA is an analytical method appropriate for monitoring the impurities of: Ag, As, Br, Cr, K, Mo, Na and Sb in the various stages of the BiI 3 purification methodology. (author)

  15. Radiation portal monitor with {sup 10}B+ZnS(Ag) neutron detector performance for the detection of special nuclear materials

    Energy Technology Data Exchange (ETDEWEB)

    Guzman G, K. A.; Gallego, E.; Lorente, A.; Ibanez F, S. [Universidad Politecnica de Madrid, Departamento de Ingenieria Energetica, ETSI Industriales, C. Jose Gutierrez Abascal 2, 28006 Madrid (Spain); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Gonzalez, J. A. [Universidad Politecnica de Madrid, Laboratorio de Ingenieria Nuclear, ETSI Caminos, Canales y Puertos, C. Prof. Aranguren 3, 28040 Madrid (Spain); Mendez, R., E-mail: ingkarenguzman@gmail.com [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Laboratorio de Patrones Neutronicos, Av. Complutense 40, 28040 Madrid (Spain)

    2016-10-15

    In homeland security, neutron detection is used to prevent the smuggling of special nuclear materials. Thermal neutrons are normally detected with {sup 3}He proportional counters, in the radiation portal monitors, Rpms, however due to the {sup 3}He shortage new procedures are being studied. In this work Monte Carlo methods, using the MCNP6 code, have been used to study the neutron detection features of a {sup 10}B+ZnS(Ag) under real conditions inside of a Rpm. The performance for neutron detection was carried out for {sup 252}Cf, {sup 238}U and {sup 239}Pu under different conditions. In order to mimic an actual situation occurring at border areas, a sample of SNM sited inside a vehicle was simulated and the Rpm with {sup 10}B+ZnS(Ag) response was calculated. At 200 cm the {sup 10}B+ZnS(Ag) on Rpm response is close to 2.5 cps-ng {sup 252}Cf, when the {sup 252}Cf neutron source is shielded with 0.5 cm-thick lead and 2.5 cm-thick polyethylene fulfilling the ANSI recommendations. Three different geometries of neutron detectors of {sup 10}B+ZnS(Ag) in a neutron detection system in Rpm were modeled. Therefore, the {sup 10}B+ZnS(Ag) detectors are an innovative and viable replacement for the {sup 3}He detectors in the Rpm. (Author)

  16. Radiation portal monitor with "1"0B+ZnS(Ag) neutron detector performance for the detection of special nuclear materials

    International Nuclear Information System (INIS)

    Guzman G, K. A.; Gallego, E.; Lorente, A.; Ibanez F, S.; Vega C, H. R.; Gonzalez, J. A.; Mendez, R.

    2016-10-01

    In homeland security, neutron detection is used to prevent the smuggling of special nuclear materials. Thermal neutrons are normally detected with "3He proportional counters, in the radiation portal monitors, Rpms, however due to the "3He shortage new procedures are being studied. In this work Monte Carlo methods, using the MCNP6 code, have been used to study the neutron detection features of a "1"0B+ZnS(Ag) under real conditions inside of a Rpm. The performance for neutron detection was carried out for "2"5"2Cf, "2"3"8U and "2"3"9Pu under different conditions. In order to mimic an actual situation occurring at border areas, a sample of SNM sited inside a vehicle was simulated and the Rpm with "1"0B+ZnS(Ag) response was calculated. At 200 cm the "1"0B+ZnS(Ag) on Rpm response is close to 2.5 cps-ng "2"5"2Cf, when the "2"5"2Cf neutron source is shielded with 0.5 cm-thick lead and 2.5 cm-thick polyethylene fulfilling the ANSI recommendations. Three different geometries of neutron detectors of "1"0B+ZnS(Ag) in a neutron detection system in Rpm were modeled. Therefore, the "1"0B+ZnS(Ag) detectors are an innovative and viable replacement for the "3He detectors in the Rpm. (Author)

  17. Relation between proton and neutron asymptotic normalization coefficients for light mirror nuclei and its relevance for nuclear astrophysics)

    International Nuclear Information System (INIS)

    Timofeyuk, N.K.; Johnson, R.C.; Descouvemont, P.

    2005-01-01

    In this talk, relation between proton and neutron Asymptotic Normalization Coefficients (ANCs) for light mirror nuclei will be discussed. This relation follows from charge symmetry of nucleon-nucleon interactions and is given by a simple approximate analytical formula which involves proton and neutron separation energies, charges of residual nuclei and the range of their strong interaction with the last nucleon. This relation is valid both for particle-bound mirror nuclear levels and for mirror pairs in which one of the levels is a narrow resonance. In the latter case, the width of this resonance is related to the ANC of its mirror particle-stable analog. Our theoretical study of mirror ANCs for several light nuclei within a framework of microscopic two-, three- and four-cluster models, have shown that the ratio of mirror ANCs changes as predicted by the simple approximate analytical formula. We will also compare the results from our microscopic calculations to the predictions of the single-particle model and discuss mirror symmetry of spectroscopic factors and single-particle ANCs. (author)

  18. Psychomotor speed is related to perceived performance in rowers

    NARCIS (Netherlands)

    Nederhof, Esther; Visscher, Chris; Lemmink, Koen

    2008-01-01

    The goal of the present study was to determine if psychomotor speed is related to perceived performance. It was hypothesized that lower perceived performance was related to longer reaction times. A total of 85 measurements were taken in 26 varsity rowers (mean age 21.3 years, s=1.6) on five

  19. Performance characteristics of specified power reactors in multidimensional neutron diffusion problems

    International Nuclear Information System (INIS)

    Kim, M.G.

    1980-01-01

    The multigroup neutron diffusion equations with the constraint of specified power distributions are investigated by the application of the straight-line method which can be considered as the limiting case of zero mesh space in the finite difference method. The standard partial differential form of the diffusion equation is reduced to sets of ordinary differential equations and then converted into sets of integral equations by using Green's functions defined on the pseudo straight lines. Coupling of each straight line to the adjacent lines arises from the application of a three-point central difference formula. The interfaces encountered between two regions are taken into account by imposing the continuity conditions for the grown fluxes and net currents with Taylor expansions of internal fluxes at the interface positions. A few sample problems are selected to test the validity of the method. It is found that the proposed method of solution is similar to the finite Fourier sine transform. Numerical results for the solutions obtained by the method of straight lines are compared with the results of the exact analytical solutions for simple geometries. These comparisons indicate that the proposed method is compatible with the analytical method, and in some problems considered the straight-line solutions are much more efficient than the exact solutions. The method is also extended to the reactor kinetics problem by expressing the kinetics parameters in terms of the basis functions which are used to obtain the solutions of the steady-state neutron diffusion equations

  20. Experimental assessment of the performance of a proposed lead slowing-down spectrometer at WNR/PSR [Weapons Neutron Research/Proton Storage Ring

    International Nuclear Information System (INIS)

    Moore, M.S.; Koehler, P.E.; Michaudon, A.; Schelberg, A.; Danon, Y.; Block, R.C.; Slovacek, R.E.; Hoff, R.W.; Lougheed, R.W.

    1990-01-01

    In November 1989, we carried out a measurement of the fission cross section of 247 Cm, 250 Cf, and 254 Es on the Rensselaer Intense Neutron Source (RINS) at Rensselaer Polytechnic Institute (RPI). In July 1990, we carried out a second measurement, using the same fission chamber and electronics, in beam geometry at the Los Alamos Neutron Scattering Center (LANSCE) facility. Using the relative count rates observed in the two experiments, and the flux-enhancement factors determined by the RPI group for a lead slowing-down spectrometer compared to beam geometry, we can assess the performance of a spectrometer similar to RINS, driven by the Proton Storage Ring (PSR) at the Los Alamos National Laboratory. With such a spectrometer, we find that is is feasible to make measurements with samples of 1 ng for fission 1 μg for capture, and of isotopes with half-lives of tens of minutes. It is important to note that, while a significant amount of information can be obtained from the low resolution RINS measurement, a definitive determination of average properties, including the level density, requires that the resonance structure be resolved. 12 refs., 5 figs., 3 tabs

  1. Experimental assessment of the performance of a proposed lead slowing-down spectrometer at WNR/PSR (Weapons Neutron Research/Proton Storage Ring)

    Energy Technology Data Exchange (ETDEWEB)

    Moore, M.S.; Koehler, P.E.; Michaudon, A.; Schelberg, A. (Los Alamos National Lab., NM (USA)); Danon, Y.; Block, R.C.; Slovacek, R.E. (Rensselaer Polytechnic Inst., Troy, NY (USA)); Hoff, R.W.; Lougheed, R.W. (Lawrence Livermore National Lab., CA (USA))

    1990-01-01

    In November 1989, we carried out a measurement of the fission cross section of {sup 247}Cm, {sup 250}Cf, and {sup 254}Es on the Rensselaer Intense Neutron Source (RINS) at Rensselaer Polytechnic Institute (RPI). In July 1990, we carried out a second measurement, using the same fission chamber and electronics, in beam geometry at the Los Alamos Neutron Scattering Center (LANSCE) facility. Using the relative count rates observed in the two experiments, and the flux-enhancement factors determined by the RPI group for a lead slowing-down spectrometer compared to beam geometry, we can assess the performance of a spectrometer similar to RINS, driven by the Proton Storage Ring (PSR) at the Los Alamos National Laboratory. With such a spectrometer, we find that is is feasible to make measurements with samples of 1 ng for fission 1 {mu}g for capture, and of isotopes with half-lives of tens of minutes. It is important to note that, while a significant amount of information can be obtained from the low resolution RINS measurement, a definitive determination of average properties, including the level density, requires that the resonance structure be resolved. 12 refs., 5 figs., 3 tabs.

  2. k0-measurements and related nuclear data compilation for (n, γ) reactor neutron activation analysis Pt. 3b

    International Nuclear Information System (INIS)

    Corte, F. de; Simonits, A.

    1989-01-01

    k 0 -factors and related nuclear data are tabulated for 112 radionuclides of interest in (n, γ) reactor neutron activation analysis. Whenever relevant, critical comments are made with respect to the accuracy of literature data for e. g. isotopic abundances, half-lives, absolute gamma-intensities and 2200 m · s -1 (n, γ) cross sections. As to the latter, a comparison is made with the values calculated from the experimentally determined k 0 -factors, by introduction of selected literature data for the input parameters. References to the table (79 pages) include 156 items. (author) 7 refs.; 1 tab

  3. Performance of a PADC personal neutron dosemeter at simulated and real workplace fields of the nuclear industry

    International Nuclear Information System (INIS)

    Fiechtner, A.; Boschung, M.; Wernli, C.

    2007-01-01

    In the framework of the EVIDOS (Evaluation of Individual Dosimetry in Mixed Neutron and Photon Radiation Fields) project, funded by the EC, measurements with PADC personal neutron dosemeters were carried out at several workplace fields of the nuclear industry and at simulated workplace fields. The measured personal neutron dose equivalents of the PADC personal neutron dosemeter are compared with values that were assessed within the EVIDOS project by other partners. The detection limits for different spectra types are given. In cases were the neutron dose was too low to be measured by the PADC personal neutron dosemeter, the response is estimated by convoluting the responses to monoenergetic neutrons with the dose energy distribution measured within EVIDOS. The advantages and limitations of the PADC personal neutron dosemeter are discussed. (authors)

  4. Reactor Neutron Sources

    International Nuclear Information System (INIS)

    Aksenov, V.L.

    1994-01-01

    The present status and the prospects for development of reactor neutron sources for neutron scattering research in the world are considered. The fields of application of neutron scattering relative to synchrotron radiation, the creation stages of reactors (steady state and pulsed) and their position in comparison with spallation neutron sources at present and in the foreseen future are discussed. (author). 15 refs.; 8 figs.; 3 tabs

  5. Evolution of magnetized, differentially rotating neutron stars: Simulations in full general relativity

    International Nuclear Information System (INIS)

    Duez, Matthew D.; Liu, Yuk Tung; Shapiro, Stuart L.; Stephens, Branson C.; Shibata, Masaru

    2006-01-01

    We study the effects of magnetic fields on the evolution of differentially rotating neutron stars, which can be formed in stellar core collapse or binary neutron star coalescence. Magnetic braking and the magnetorotational instability (MRI) both act on differentially rotating stars to redistribute angular momentum. Simulations of these stars are carried out in axisymmetry using our recently developed codes which integrate the coupled Einstein-Maxwell-MHD equations. We consider stars with two different equations of state (EOS), a gamma-law EOS with Γ=2, and a more realistic hybrid EOS, and we evolve them adiabatically. Our simulations show that the fate of the star depends on its mass and spin. For initial data, we consider three categories of differentially rotating, equilibrium configurations, which we label normal, hypermassive and ultraspinning. Normal configurations have rest masses below the maximum achievable with uniform rotation, and angular momentum below the maximum for uniform rotation at the same rest mass. Hypermassive stars have rest masses exceeding the mass limit for uniform rotation. Ultraspinning stars are not hypermassive, but have angular momentum exceeding the maximum for uniform rotation at the same rest mass. We show that a normal star will evolve to a uniformly rotating equilibrium configuration. An ultraspinning star evolves to an equilibrium state consisting of a nearly uniformly rotating central core, surrounded by a differentially rotating torus with constant angular velocity along magnetic field lines, so that differential rotation ceases to wind the magnetic field. In addition, the final state is stable against the MRI, although it has differential rotation. For a hypermassive neutron star, the MHD-driven angular momentum transport leads to catastrophic collapse of the core. The resulting rotating black hole is surrounded by a hot, massive, magnetized torus undergoing quasistationary accretion, and a magnetic field collimated along

  6. Hormone receptor densities in relation to 10B neutron capture therapy

    International Nuclear Information System (INIS)

    Hechter, O.; Schwartz, I.L.

    1982-01-01

    This presentation is a theoretical discussion of the possibility that appropriate steroid-carborane derivatives might be used to selectively deliver boron-10 ( 10 B) to tumor cells with sex-hormone receptors in sufficient concentration for effective neutron capture theory (NCT) of hormone-dependent mammary and prostatic cancer. The results indicate the concentrations of androgen receptors (AR) and progesterone receptors (PR) in malignant prostatic cells or of estrogen receptors (ER) in malignant mammary cells are two low to achieve nuclear 10 B concentrations of 1 + g per g of tumor by using a steroid ligand coupled to a single carborane cage

  7. Relative measurement of the fluxes of thermal, resonant and rapid neutrons in reactor G1

    International Nuclear Information System (INIS)

    Carle, R.; Mazancourt, T. de

    1957-01-01

    We sought to determine the behavior of the thermal, resonant and rapid neutron fluxes in the multiplier-reflector transition region, in the two principal directions of the system. We have also measured the variation of these different fluxes in the body of the multiplier medium in a canal filled with graphite and in an empty canal. The results are given in the form of curves representing: - the variation of the ratio of the thermal flux to the rapid flux in axial and radial transitions - the behavior of the thermal and resonant fluxes and the variation of their ratio in the same regions. (author) [fr

  8. Generalized Thermohydraulics Module GENFLO for Combining With the PWR Core Melting Model, BWR Recriticality Neutronics Model and Fuel Performance Model

    International Nuclear Information System (INIS)

    Miettinen, Jaakko; Hamalainen, Anitta; Pekkarinen, Esko

    2002-01-01

    Thermal hydraulic simulation capability for accident conditions is needed at present in VTT in several programs. Traditional thermal hydraulic models are too heavy for simulation in the analysis tasks, where the main emphasis is the rapid neutron dynamics or the core melting. The GENFLO thermal hydraulic model has been developed at VTT for special applications in the combined codes. The basic field equations in GENFLO are for the phase mass, the mixture momentum and phase energy conservation equations. The phase separation is solved with the drift flux model. The basic variables to be solved are the pressure, void fraction, mixture velocity, gas enthalpy, liquid enthalpy, and concentration of non-condensable gas fractions. The validation of the thermohydraulic solution alone includes large break LOCA reflooding experiments and in specific for the severe accident conditions QUENCH tests. In the recriticality analysis the core neutronics is simulated with a two-dimensional transient neutronics code TWODIM. The recriticality with one rapid prompt peak is expected during a severe accident scenario, where the control rods have been melted and ECCS reflooding is started after the depressurization. The GENFLO module simulates the BWR thermohydraulics in this application. The core melting module has been developed for the real time operator training by using the APROS engineering simulators. The core heatup, oxidation, metal and fuel pellet relocation and corium pool formation into the lower plenum are calculated. In this application the GENFLO model simulates the PWR vessel thermohydraulics. In the fuel performance analysis the fuel rod transient behavior is simulated with the FRAPTRAN code. GENFLO simulates the subchannel around a single fuel rod and delivers the heat transfer on the cladding surface for the FRAPTRAN. The transient boundary conditions for the subchannel are transmitted from the system code for operational transient, loss of coolant accidents and

  9. Analysis of zirconium and nickel based alloys and zirconium oxides by relative and internal monostandard neutron activation analysis methods

    International Nuclear Information System (INIS)

    Shinde, Amol D.; Acharya, Raghunath; Reddy, Annareddy V. R.

    2017-01-01

    The chemical characterization of metallic alloys and oxides is conventionally carried out by wet chemical analytical methods and/or instrumental methods. Instrumental neutron activation analysis (INAA) is capable of analyzing samples nondestructively. As a part of a chemical quality control exercise, Zircaloys 2 and 4, nimonic alloy, and zirconium oxide samples were analyzed by two INAA methods. The samples of alloys and oxides were also analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES) and direct current Arc OES methods, respectively, for quality assurance purposes. The samples are important in various fields including nuclear technology. Samples were neutron irradiated using nuclear reactors, and the radioactive assay was carried out using high-resolution gamma-ray spectrometry. Major to trace mass fractions were determined using both relative and internal monostandard (IM) NAA methods as well as OES methods. In the case of alloys, compositional analyses as well as concentrations of some trace elements were determined, whereas in the case of zirconium oxides, six trace elements were determined. For method validation, British Chemical Standard (BCS)-certified reference material 310/1 (a nimonic alloy) was analyzed using both relative INAA and IM-NAA methods. The results showed that IM-NAA and relative INAA methods can be used for nondestructive chemical quality control of alloys and oxide samples

  10. Analysis of zirconium and nickel based alloys and zirconium oxides by relative and internal monostandard neutron activation analysis methods

    Energy Technology Data Exchange (ETDEWEB)

    Shinde, Amol D.; Acharya, Raghunath; Reddy, Annareddy V. R. [Bhabha Atomic Research Centre, Mumbai (India)

    2017-04-15

    The chemical characterization of metallic alloys and oxides is conventionally carried out by wet chemical analytical methods and/or instrumental methods. Instrumental neutron activation analysis (INAA) is capable of analyzing samples nondestructively. As a part of a chemical quality control exercise, Zircaloys 2 and 4, nimonic alloy, and zirconium oxide samples were analyzed by two INAA methods. The samples of alloys and oxides were also analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES) and direct current Arc OES methods, respectively, for quality assurance purposes. The samples are important in various fields including nuclear technology. Samples were neutron irradiated using nuclear reactors, and the radioactive assay was carried out using high-resolution gamma-ray spectrometry. Major to trace mass fractions were determined using both relative and internal monostandard (IM) NAA methods as well as OES methods. In the case of alloys, compositional analyses as well as concentrations of some trace elements were determined, whereas in the case of zirconium oxides, six trace elements were determined. For method validation, British Chemical Standard (BCS)-certified reference material 310/1 (a nimonic alloy) was analyzed using both relative INAA and IM-NAA methods. The results showed that IM-NAA and relative INAA methods can be used for nondestructive chemical quality control of alloys and oxide samples.

  11. Relative light yield and temporal response of a stilbene-doped bibenzyl organic scintillator for neutron detection

    Energy Technology Data Exchange (ETDEWEB)

    Brown, J. A.; Goldblum, B. L., E-mail: bethany@nuc.berkeley.edu; Brickner, N. M.; Daub, B. H.; Kaufman, G. S.; Bibber, K. van; Vujic, J. [Department of Nuclear Engineering, University of California, Berkeley, California 94720 (United States); Bernstein, L. A.; Bleuel, D. L.; Caggiano, J. A.; Hatarik, R.; Phillips, T. W.; Zaitseva, N. P. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Wender, S. A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2014-05-21

    The neutron time-of-flight (nTOF) diagnostics used to characterize implosions at the National Ignition Facility (NIF) has necessitated the development of novel scintillators that exhibit a rapid temporal response and high light yield. One such material, a bibenzyl-stilbene mixed single-crystal organic scintillator grown in a 99.5:0.5 ratio in solution, has become the standard scintillator used for nTOF diagnostics at NIF. The prompt fluorescence lifetime and relative light yield as a function of proton energy were determined to calibrate this material as a neutron detector. The temporal evolution of the intensity of the prompt fluorescent response was modeled using first-order reaction kinetics and the prompt fluorescence decay constant was determined to be 2.46 ± 0.01 (fit) ± 0.13 (systematic) ns. The relative response of the bibenzyl-stilbene mixed crystal generated by recoiling protons was measured, and results were analyzed using Birks' relation to quantify the non-radiative quenching of excitation energy in the scintillator.

  12. Application of the Instrumental Neutron Activation Analysis and High Performance Liquid Chromatography (HPLC) in the rare earth elements determination in reference geological materials

    International Nuclear Information System (INIS)

    Figueiredo, Ana M.G.; Moraes, Noemia M.P. de; Shihomatsu, Helena M.

    1997-01-01

    Instrumental Neutron Activation Analysis (INAA) and High Performance Liquid Chromatography (HPLC) were applied to the determination of rare earth elements (REE) in the geological reference materials AGV-1, G-2 and GSP-1 (USGS). Results obtained by both techniques showed good agreement with certified values, giving relative errors less than 10%. The La, Ce, Nd, Sm, Eu, Tb, Yb and Lu REE elements were determined. All the REE except Dy and Y were determined by HPLC. The reference material G94, employed in the International Proficiency Test for Analytical Geochemistry Laboratories (GeoTP1) was analysed. The results obtained are a contribution to REE contents in this sample. The INAA and HPLC application to the determination of REE in this kind of matrix is also discussed. (author). 10 refs., 1 fig., 5 tabs

  13. Pulsed neutron sources for epithermal neutrons

    International Nuclear Information System (INIS)

    Windsor, C.G.

    1978-01-01

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

  14. Evaluation of three partially volatile neutron shields for high-performance shipping casks

    International Nuclear Information System (INIS)

    Rack, H.J.; Pearson, H.S.

    1981-02-01

    The thermal stability and mechanical behavior of three partially volatile candidate neutron shield materials have been evaluated. The results indicate that silicone based rubbers, impregnated with elemental boron or boron carbide, Boro-silicone 236 and Bisco NS-I respectively are more thermally stable than are borated beechwoods, e.g., Permali JN. Mechanical property measurements indicated however that the compressive strength of the borated beechwood is 10 to 48 times higher than that of the silicone-based rubbers. The compressive strengths of the borated beechwood and boron carbide impregnated silicone rubber were substantially more sensitive to test temperature than was the compressive strength of the boron impregnated silicone rubber. Finally the compressive strengths and energy absorbing capability of the boron impregnated silicone rubber is not affected by prior thermal exposure at 425 0 K for 1000h

  15. Merger of white dwarf-neutron star binaries: Prelude to hydrodynamic simulations in general relativity

    International Nuclear Information System (INIS)

    Paschalidis, Vasileios; MacLeod, Morgan; Baumgarte, Thomas W.; Shapiro, Stuart L.

    2009-01-01

    White dwarf-neutron star binaries generate detectable gravitational radiation. We construct Newtonian equilibrium models of corotational white dwarf-neutron star (WDNS) binaries in circular orbit and find that these models terminate at the Roche limit. At this point the binary will undergo either stable mass transfer (SMT) and evolve on a secular time scale, or unstable mass transfer (UMT), which results in the tidal disruption of the WD. The path a given binary will follow depends primarily on its mass ratio. We analyze the fate of known WDNS binaries and use population synthesis results to estimate the number of LISA-resolved galactic binaries that will undergo either SMT or UMT. We model the quasistationary SMT epoch by solving a set of simple ordinary differential equations and compute the corresponding gravitational waveforms. Finally, we discuss in general terms the possible fate of binaries that undergo UMT and construct approximate Newtonian equilibrium configurations of merged WDNS remnants. We use these configurations to assess plausible outcomes of our future, fully relativistic simulations of these systems. If sufficient WD debris lands on the NS, the remnant may collapse, whereby the gravitational waves from the inspiral, merger, and collapse phases will sweep from LISA through LIGO frequency bands. If the debris forms a disk about the NS, it may fragment and form planets.

  16. Study of a nTHGEM-based thermal neutron detector

    Science.gov (United States)

    Li, Ke; Zhou, Jian-Rong; Wang, Xiao-Dong; Xiong, Tao; Zhang, Ying; Xie, Yu-Guang; Zhou, Liang; Xu, Hong; Yang, Gui-An; Wang, Yan-Feng; Wang, Yan; Wu, Jin-Jie; Sun, Zhi-Jia; Hu, Bi-Tao

    2016-07-01

    With new generation neutron sources, traditional neutron detectors cannot satisfy the demands of the applications, especially under high flux. Furthermore, facing the global crisis in 3He gas supply, research on new types of neutron detector as an alternative to 3He is a research hotspot in the field of particle detection. GEM (Gaseous Electron Multiplier) neutron detectors have high counting rate, good spatial and time resolution, and could be one future direction of the development of neutron detectors. In this paper, the physical process of neutron detection is simulated with Geant4 code, studying the relations between thermal conversion efficiency, boron thickness and number of boron layers. Due to the special characteristics of neutron detection, we have developed a novel type of special ceramic nTHGEM (neutron THick GEM) for neutron detection. The performance of the nTHGEM working in different Ar/CO2 mixtures is presented, including measurements of the gain and the count rate plateau using a copper target X-ray source. A detector with a single nTHGEM has been tested for 2-D imaging using a 252Cf neutron source. The key parameters of the performance of the nTHGEM detector have been obtained, providing necessary experimental data as a reference for further research on this detector. Supported by National Natural Science Foundation of China (11127508, 11175199, 11205253, 11405191), Key Laboratory of Neutron Physics, CAEP (2013DB06, 2013BB04) and CAS (YZ201512)

  17. Inelastic Neutron Scattering Measurements of Phonon Dispersion Relations in Andalusite and Sillimanite, Al2SiO5

    International Nuclear Information System (INIS)

    Goel, P.

    2001-01-01

    This paper reports inelastic neutron scattering (INS) measurements of the phonon dispersion relations of the aluminum silicate minerals andalusite and sillimanite, Al 2 SiO 5 . The single crystal INS measurements were undertaken using the Triple-axis-spectrometer at the Dhruva reactor, Trombay for andalusite and at the Oak Ridge National Laboratory, USA for sillimanite. The phonon dispersion relations (upto 50 mev) along various high symmetry directions have been measured and have been analyzed on the basis of lattice dynamics shell model calculations. The calculated structure factors based on the model calculations were used as guides for planning these single crystal measurements and were used to identify regions in reciprocal space with large cross-sections. The calculated structure factors have been very useful in the planning, execution and analysis of the experimental data. The calculated phonon dispersion relations are found to be in good agreement with the measured data

  18. Polarized neutrons

    International Nuclear Information System (INIS)

    Williams, W.G.

    1988-01-01

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

  19. Relative Performance Information, Rank Ordering and Employee Performance: A Research Note

    NARCIS (Netherlands)

    Kramer, S.; Maas, V.S.; van Rinsum, M.

    2016-01-01

    We conduct a laboratory experiment to examine whether the provision of detailed relative performance information (i.e., information about the specific performance levels of peers) affects employee performance. We also investigate how – if at all – explicit ranking of performance levels affects how

  20. Relative cataractogenic effects of X rays, fission-spectrum neutrons, and 56Fe particles: A comparison with mitotic effects

    International Nuclear Information System (INIS)

    Riley, E.F.; Lindgren, A.L.; Andersen, A.L.; Miller, R.C.; Ainsworth, E.J.

    1991-01-01

    The eyes of Sprague-Dawley rats were irradiated with doses of 2.5-10 Gy 250-kVp X rays, 1.25-2.25 Gy fission-spectrum neutrons (approximately 0.85 MeV), or 0.1-2.0 Gy 600-MeV/A 56Fe particles. Lens opacifications were evaluated for 51-61 weeks following X and neutron irradiations and for 87 weeks following X and 56Fe-particle irradiations. Average stage of opacification was determined relative to time after irradiation, and the time required for 50% of the irradiated lenses to achieve various stages (T50) was determined as a function of radiation dose. Data from two experiments were combined in dose-effect curves as T50 experimental values taken as percentages of the respective T50 control values (T50-% control). Simple exponential curves best describe dose responsiveness for both high-LET radiations. For X rays, a shallow dose-effect relationship (shoulder) up to 4.5 Gy was followed at higher doses by a steeper exponential dose-effect relationship. As a consequence, RBE values for the high-LET radiations are dose dependent. Dose-effect curves for cataracts were compared to those for mitotic abnormalities observed when quiescent lens epithelial cells were stimulated mechanically to proliferate at various intervals after irradiation. Neutrons were about 1.6-1.8 times more effective than 56Fe particles for inducing both cataracts and mitotic abnormalities. For stage 1 and 2 cataracts, the X-ray Dq was 10-fold greater and the D0 was similar to those for mitotic abnormalities initially expressed after irradiation

  1. Neutron--neutron logging

    International Nuclear Information System (INIS)

    Allen, L.S.

    1977-01-01

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

  2. Research related to boron neutron capture therapy at The Ohio State University

    International Nuclear Information System (INIS)

    Barth, R.F.; Soloway, A.H.; Alam, F.

    1986-01-01

    Research in the area of boron neutron capture therapy (BNCT) at The Ohio State University is a highly multidisciplinary effort involving approximately twenty investigators in nine different departments. Major areas of interest include: (1) Boronation of monoclonal antibodies directed against tumor-associated antigens for the delivery of 10 B; (2) Synthesis of 10 B-containing derivatives of promazines and porphyrins that possess tumor-localizing properties; (3) Development of a rat model for the treatment of glioblastoma by BNCT; (4) Quantitation and microdistribution of 10 B in tissues by means of a solid state nuclear track detector. The ultimate goal of this research is to carry out the extensive preclinical studies that are required to bring BNCT to the point of a clinical trial. 13 references

  3. Shape transitions in neutron rich 110-112Ru nuclei and empirical relations

    International Nuclear Information System (INIS)

    Bihari, Chhail; Singh, Yuvraj; Gupta, K.K.; Varshney, A.K.; Singh, M.; Gupta, D.K.

    2010-01-01

    In the study of even even neutron rich Ru isotopes, the electromagnetic properties of the γ-vibrational bands are well described by a rigid triaxial rotor for lower spin state and by the rotation vibration collective model for the higher spin states. Thus interpretation in further suggested by the observation of nearly identical moment of inertia, the rotational frequency below the first band crossing, between the ground state and the γ-structural bands for both 110 Ru and 112 Ru which conclude a weak pairing, a more likely suitable explanation of observations. In the present work, the soft rotor energy formula is undertaken suggested by Brentano et al. for yrast band, may be employed to calculate the perturbed energies of the anomalous rotational band (γ-band) generated by rotation of the rigid asymmetric atomic nucleus and the two parameter formula (TPF) of Gupta et al.

  4. Trends and Developments for Fast Neutron Reactors and Related Fuel Cycles

    International Nuclear Information System (INIS)

    Carré, Frank

    2013-01-01

    • FR13 – A unique and dedicated framework to share updates on national programs of Fast Reactor developments, projects of new builds and plans for the future: - Near term projects of sodium and lead-alloy Fast Reactors; - Gen-IV visions of sodium-cooled and alternative types of Fast Neutron Reactors (GFR, LFR…). • FR13 – A special emphasis put on Fast Reactor Safety, Sustainability of nuclear fuel cycle and Young Generation perspective. • FR13 – A catalyst for further collaborations and alliances: - To share visions of goals and advisable options for future Fast Reactors and Nuclear Fuel Cycle; - To share cost of R&D and large demonstrations (safety, security, recycling); - To progress towards harmonized international standards; - To integrate national projects into a consistent international roadmap

  5. Performance-related pay and gender wage differences

    OpenAIRE

    Kangasniemi, Mari; Kauhanen, Antti

    2011-01-01

    We study the impact of performance-related pay (PRP) on gender wage differences using Finnish linked employer-employee panel data. Controlling for unobserved person and firm effects, we find that bonuses increase women's earnings slightly less than men's, but the economic significance of the difference is negligible. Piece rates and reward rates, however, tend to increase gender wage differentials. Thus, the nature of a performance related pay plan is important for gauging the impact of PRP o...

  6. Neutron source investigations in support of the cross section program at the Argonne Fast-Neutron Generator

    International Nuclear Information System (INIS)

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

    1980-05-01

    Experimental methods related to the production of neutrons for cross section studies at the Argonne Fast-Neutron Generator are reviewed. Target assemblies commonly employed in these measurements are described, and some of the relevant physical properties of the neutron source reactions are discussed. Various measurements have been performed to ascertain knowledge about these source reaction that is required for cross section data analysis purposes. Some results from these studies are presented, and a few specific examples of neutron-source-related corrections to cross section data are provided. 16 figures, 3 tables

  7. Neutron transportation simulator

    International Nuclear Information System (INIS)

    Uenohara, Yuzo.

    1995-01-01

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

  8. Dimensions in Appraising Fatigue in Relation to Performance

    NARCIS (Netherlands)

    Dam, A. van; Keijsers, G.P.J.; Eling, P.A.T.M.

    2011-01-01

    Studies on the relation between fatigue and performance often fail to find a strong and direct link, implying that multiple factors may be involved. A literature search on the fatigue-performance relationship suggests that two different conceptual frameworks are employed concerning the appraisal of

  9. Factors Affecting Performance of Undergraduate Students in Construction Related Disciplines

    Science.gov (United States)

    Olatunji, Samuel Olusola; Aghimien, Douglas Omoregie; Oke, Ayodeji Emmanuel; Olushola, Emmanuel

    2016-01-01

    Academic performance of students in Nigerian institutions has been of much concern to all and sundry hence the need to assess the factors affecting performance of undergraduate students in construction related discipline in Nigeria. A survey design was employed with questionnaires administered on students in the department of Quantity Surveying,…

  10. Impact of neutron irradiation on mechanical performance of FeCrAl alloy laser-beam weldments

    Science.gov (United States)

    Gussev, M. N.; Cakmak, E.; Field, K. G.

    2018-06-01

    Oxidation-resistant iron-chromium-aluminum (FeCrAl) alloys demonstrate better performance in Loss-of-Coolant Accidents, compared with austenitic- and zirconium-based alloys. However, further deployment of FeCrAl-based materials requires detailed characterization of their performance under irradiation; moreover, since welding is one of the key operations in fabrication of light water reactor fuel cladding, FeCrAl alloy weldment performance and properties also should be determined prior to and after irradiation. Here, advanced C35M alloy (Fe-13%Cr-5%Al) and variants with aluminum (+2%) or titanium carbide (+1%) additions were characterized after neutron irradiation in Oak Ridge National Laboratory's High Flux Isotope Reactor at 1.8-1.9 dpa in a temperature range of 195-559 °C. Specimen sets included as-received (AR) materials and specimens after controlled laser-beam welding. Tensile tests with digital image correlation (DIC), scanning electron microscopy-electron back scatter diffraction analysis, fractography, and x-ray tomography analysis were performed. DIC allowed for investigating local yield stress in the weldments, deformation hardening behavior, and plastic anisotropy. Both AR and welded material revealed a high degree of radiation-induced hardening for low-temperature irradiation; however, irradiation at high-temperatures (i.e., 559 °C) had little overall effect on the mechanical performance.

  11. Fail-safe neutron shutter used for thermal neutron radiography

    International Nuclear Information System (INIS)

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

    1976-11-01

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

  12. New mass analysis and results for neutron rich nuclei performed with isochronous mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Diwisch, Marcel [Justus-Liebig-Universitaet Giessen, Giessen (Germany); Knoebel, Ronja; Geissel, Hans; Plass, Wolfgang; Scheidenberger, Christoph [Justus-Liebig-Universitaet Giessen, Giessen (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Patyk, Zygmunt [Soltan Institute for Nuclear Studies, Warsaw (Poland); Weick, Helmut [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany)

    2015-07-01

    The Isochronous Mass Spectrometry (IMS) allows to measure masses of rare exotic nuclei in a storage ring in a timescale of tens of μs. The ring is operated in an isochronous mode, i.e. such that particles with different velocities but same mass-to-charge ratio (m/q) travel different paths in the ring arcs (faster ions travel longer paths whereas slower ions travel shorter paths). This means that for each m/q a fix revolution time exists and can be measured by a time-of-flight (TOF) detector which then yields the masses of the nuclei for known charge states. A new analysis approach of IMS data with a correlation matrix method allowed combining data with different quality. The latest production run was using an additional determination of the magnetic rigidity which increased the resolving power of the experiment. Combining this experiment with previous experiments one can increase the statistics and accuracy of the overall mass determination. It was possible to deduce mass values of neutron rich isotopes which have not been measured before. One of those isotopes is {sup 130}Cd which is a very important nuclei involved in the r-process. Those mass values and a comparison to theoretical predictions will be presented in the poster.

  13. Database on Performance of Neutron Irradiated FeCrAl Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Briggs, Samuel A. [Univ. of Wisconsin, Madison, WI (United States); Littrell, Ken [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Parish, Chad M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-08-01

    The present report summarizes and discusses the database on radiation tolerance for Generation I, Generation II, and commercial FeCrAl alloys. This database has been built upon mechanical testing and microstructural characterization on selected alloys irradiated within the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) up to doses of 13.8 dpa at temperatures ranging from 200°C to 550°C. The structure and performance of these irradiated alloys were characterized using advanced microstructural characterization techniques and mechanical testing. The primary objective of developing this database is to enhance the rapid development of a mechanistic understanding on the radiation tolerance of FeCrAl alloys, thereby enabling informed decisions on the optimization of composition and microstructure of FeCrAl alloys for application as an accident tolerant fuel (ATF) cladding. This report is structured to provide a brief summary of critical results related to the database on radiation tolerance of FeCrAl alloys.

  14. Development and performance test of a system available for generating multiple extreme conditions for neutron scattering experiments

    International Nuclear Information System (INIS)

    Kawano, Shinji; Fukui, Susumu; Moriai, Atsushi; Ohtomo, Akitoshi; Ichimura, Shigeki; Onodera, Akifumi; Amita, F.; Katano, Susumu

    1998-01-01

    We have developed unique system available for controlling sample environment during the neutron scattering experiments. The system can simultaneously generate triple extreme conditions of low temperature, high magnetic field and high pressure. The system consists of: (i) a liquid-helium cryostat variable for sample temperature from 1.7 K to 200 K, (ii) a superconducting magnet providing a vertical field up to ±5 T with an antisymmetric split-coil geometry for polarized-beam experiments, and (iii) a non-magnetic piston-cylinder high-pressure cell designed with the aim of generating hydrostatic pressure up to 2.5 GPa. In the presentation, we will report the outline of the system and some results of performance tests at KURRI and JRR-3M of JAERI. (author)

  15. Performance Monitoring for Nuclear Safety Related Instrumentation at PUSPATI TRIGA Reactor (RTP)

    International Nuclear Information System (INIS)

    Zareen Khan Abdul Jalil Khan; Ridzuan Abdul Mutalib; Mohd Sabri Minhat

    2015-01-01

    The Reactor TRIGA PUSPATI (RTP) at Malaysia Nuclear Agency is a TRIGA Mark II type reactor and pool type cooled by natural circulation of light water. This paper describe on performance monitoring for nuclear safety related instrumentation in TRIGA PUSPATI Reactor (RTP) of based on various parameter of reactor safety instrument channel such as log power, linear power, Fuel temperature, coolant temperature will take into consideration. Methodology of performance on estimation and monitoring is to evaluate and analysis of reactor parameters which is important of reactor safety and control. And also to estimate power measurement, differential of log and linear power and fuel temperature during reactor start-up, operation and shutdown .This study also focus on neutron power fluctuation from fission chamber during reactor start-up and operation. This work will present result of performance monitoring from RTP which indicated the safety parameter identification and initiate safety action on crossing the threshold set point trip. Conclude that performance of nuclear safety related instrumentation will improved the reactor control and safety parameter during reactor start-up, operation and shutdown. (author)

  16. The Green's function approach to the neutron-inelastic-scattering determination of magnon dispersion relations for isotropic disordered magnets

    International Nuclear Information System (INIS)

    Czachor, A.; Al-Wahsh, H.

    1999-01-01

    Complete text of publication follows. To determine the neutron inelastic coherent scattering (MS) cross section for disordered magnets a system of equations of motion for the Green functions (GF) related to the localized-spin correlation-functions, has been exploited. The higher-order Green functions are decoupled using a symmetric 'equal access' (EA) form of the RPA decoupling scheme. The quasi-crystal approximation (QCA) was applied to construct the space-time Fourier transformed GF Q (ω)> related to neutron scattering. On assuming isotropy of the magnetic structure and a short range coupling between the spins (on the sphere approximation, OSA) we have found an explicit analytic form of this function. Poles of the Q (ω)> determine the dispersion relation ω = ω Q for elementary excitations, such as they are seen in the MS experiment - the positions of the MS profile maxima in the ω-Q space. Single formula for the dispersion relations derived here covers a variety of isotropic spin structures: in particular disordered 'longitudinal' ferrornagnets (ω ∼Q z , Q→ 0), disordered 'transverse' spin structures (ω ∼Q, Q→0), and some intermediate cases. For the system of spins coupled identically - the magnetization and the magnetic susceptibility calculated within the present EA-RPA approach do agree with the results of exact calculations. It provides an interesting insight into the nature of the RPA approach do agree with the results of exact calculations. It provides an interesting insight into the nature of the RPA - treatment of the localized spin dynamics. (author)

  17. Analysis of business process maturity and organisational performance relations

    Directory of Open Access Journals (Sweden)

    Kalinowski T. Bartosz

    2016-12-01

    Full Text Available The paper aims to present results of the study on business process maturity in relation to organisational performance. A two-phase methodology, based on literature review and survey was used. The literature is a source of knowledge about business process maturity and organisational performance, whereas the research on process maturity vs organisational performance in Polish Enterprises provides findings based on 84 surveyed companies. The main areas of the research covered: identification and analysis of maturity related variables and identification of organisational performance perspectives and its relation to process maturity. The study shows that there is a significant positive relation between process maturity and organisational performance. Although there are research on such relation available, they are scarce and have some significant limitations in terms of research sample or the scope of maturity or organisational performance covered. This publication is part of a project funded by the National Science Centre awarded by decision number DEC-2011/01/D/HS4/04070.

  18. First results of micro-neutron tomography by use of a focussing neutron lens

    CERN Document Server

    Masschaele, B; Cauwels, P; Dierick, M; Jolie, J; Mondelaers, W

    2001-01-01

    Since the appearance of high flux neutron beams, scientists experimented with neutron radiography. This high beam flux combined with modern neutron to visible light converters leads to the possibility of performing fast neutron micro-tomography. The first results of cold neutron tomography with a neutron lens are presented in this article. Samples are rotated in the beam and the projections are recorded with a neutron camera. The 3D reconstruction is performed with cone beam reconstruction software.

  19. Achievement and development of neutron beam utilization in research reactors

    International Nuclear Information System (INIS)

    Isshiki, Masahiko

    1996-01-01

    Especially regarding the neutron beam experiment in Japan, the basic research has been developed by utilizing the JRR-2 of Japan Atomic Energy Research Institute and the KUR of Kyoto University over long years. Now, the JRR-3M of JAERI was revived as a high performance, general purpose reactor, and bears important roles as the neutron beam experiment center in Japan. Thanks to one of the most powerful reactor neutron sources in the world and the cold neutron source, the environment of research was greatly improved, and the excellent results of researches began to be reported. The discovery of neutrons by Chadwick and the history of the related researches are described. As neutron sources, radioisotopes, accelerators and nuclear reactors are properly used corresponding to purposes. As the utilization of research reactors for neutron sources, the utilization for irradiation and neutron beam experiment are carried out. The outline of the research reactor JRR-3M is explained. The state of utilization in neutron scattering experiment, neutron radiography, prompt γ-ray analysis and the medical irradiation of neutrons is reported. (K.I.)

  20. Utilization of fusion neutrons in the tokamak fusion test reactor for blanket performance testing and other nuclear engineering experiments

    International Nuclear Information System (INIS)

    Caldwell, C.S.; Pettus, W.G.; Schmotzer, J.K.; Welfare, F.; Womack, R.

    1979-01-01

    In addition to developing a set of reacting-plasma/blanket-neutronics benchmark data, the TFTR fusion application experiments would provide operational experience with fast-neutron dosimetry and the remote handling of blanket modules in a tokamak reactor environment; neutron streaming and hot-spot information invaluable for the optimal design of penetrations in future fusion reactors; and the identification of the most damage-resistant insulators for a variety of fusion-reactor components

  1. Development of DUPIC safeguards neutron counter

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Gil; Cha, Hong Ryul; Kim, Ho Dong; Hong, Jong Sook; Kang, Hee Young

    1999-08-01

    KAERI, in cooperation with LANL, developed DSNC (DUPIC Safeguards Neutron Counter) for safeguards implementing on DUPIC process which is under development by KAERI for direct use of spent PWR fuel in CANDU reactors. DSNC is a well-type neutron coincidence counter with substantial shielding to protect system from high gamma radiation of spent fuel. General development procedures in terms of design, manufacturing, fabrication, cold and hot test, performance test for DSNC authentication by KAERI-IAEA-LANL are described in this report. It is expected that the techniques related DSNC development and associated neutron detection and evaluation method could be applied for safeguards improvement. (Author). 20 refs., 16 tabs. 98 figs.

  2. VESUVIO: a novel instrument for performing spectroscopic studies in condensed matter with eV neutrons at the ISIS facility

    Science.gov (United States)

    Senesi, R.; Andreani, C.; Bowden, Z.; Colognesi, D.; Degiorgi, E.; Fielding, A. L.; Mayers, J.; Nardone, M.; Norris, J.; Praitano, M.; Rhodes, N. J.; Stirling, W. G.; Tomkinson, J.; Uden, C.

    2000-03-01

    The VESUVIO project aims to provide unique prototype instrumentation at the ISIS-pulsed neutron source and to establish a routine experimental and theoretical program in neutron scattering spectroscopy at eV energies. This instrumentation will be specifically designed for high momentum, (20 Å-11 eV) inelastic neutron scattering studies of microscopic dynamical processes in materials and will represent a unique facility for EU researchers. It will allow to derive single-particle kinetic energies and single-particle momentum distributions, n(p), providing additional and/or complementary information to other neutron inelastic spectroscopic techniques.

  3. Energy dependence of relative abundances and periods of separate groups of delayed neutrons at neutron induced fission of 239Pu in a range of neutrons energies 0.37 - 5 MeV

    International Nuclear Information System (INIS)

    Roschenko, V.A.; Piksaikin, V.M.; Kazakov, L.E.; Isaev, S.G.; Korolev, G.G.; Tarasko, M.Z.; Tertychnyi, R.G.

    2001-01-01

    The fundamental role of delayed neutrons in behavior, control and safety of reactors is well known today. Delayed neutron data are of great interest not only for reactor physics but also for nuclear fission physics and astrophysics. The purpose of the present work was the measurement of energy dependence of delayed neutrons (DN) group parameters at fission of nuclei 239 Pu in a range of energies of primary neutrons from 0.37 up to 5 MeV. The measurements were executed on installation designed on the basis of the electrostatic accelerator of KG - 2.5 SSC RF IPPE. The data are obtained in 6-group representation. It is shown, that there is a significant energy dependence of DN group parameters in a range of primary neutrons energies from thermal meanings up to 5 MeV, which is expressed in reduction of the average half-life of nuclei of the DN precursors on 10 %. The data, received in the present work, can be used at creation of a set of group constants for reactors with an intermediate spectrum of neutrons. (authors)

  4. Characterization of the γ background in epithermal neutron scattering measurements at pulsed neutron sources

    International Nuclear Information System (INIS)

    Pietropaolo, A.; Tardocchi, M.; Schooneveld, E.M.; Senesi, R.

    2006-01-01

    This paper reports the characterization of the different components of the γ background in epithermal neutron scattering experiments at pulsed neutron sources. The measurements were performed on the VESUVIO spectrometer at ISIS spallation neutron source. These measurements, carried out with a high purity germanium detector, aim to provide detailed information for the investigation of the effect of the γ energy discrimination on the signal-to-background ratio. It is shown that the γ background is produced by different sources that can be identified with their relative time structure and relative weight

  5. Simulated astigmatism impairs academic-related performance in children.

    Science.gov (United States)

    Narayanasamy, Sumithira; Vincent, Stephen J; Sampson, Geoff P; Wood, Joanne M

    2015-01-01

    Astigmatism is an important refractive condition in children. However, the functional impact of uncorrected astigmatism in this population is not well established, particularly with regard to academic performance. This study investigated the impact of simulated bilateral astigmatism on academic-related tasks before and after sustained near work in children. Twenty visually normal children (mean age: 10.8 ± 0.7 years; six males and 14 females) completed a range of standardised academic-related tests with and without 1.50 D of simulated bilateral astigmatism (with both academic-related tests and the visual condition administered in a randomised order). The simulated astigmatism was induced using a positive cylindrical lens while maintaining a plano spherical equivalent. Performance was assessed before and after 20 min of sustained near work, during two separate testing sessions. Academic-related measures included a standardised reading test (the Neale Analysis of Reading Ability), visual information processing tests (Coding and Symbol Search subtests from the Wechsler Intelligence Scale for Children) and a reading-related eye movement test (the Developmental Eye Movement test). Each participant was systematically assigned either with-the-rule (WTR, axis 180°) or against-the-rule (ATR, axis 90°) simulated astigmatism to evaluate the influence of axis orientation on any decrements in performance. Reading, visual information processing and reading-related eye movement performance were all significantly impaired by both simulated bilateral astigmatism (p  0.05). Simulated astigmatism led to a reduction of between 5% and 12% in performance across the academic-related outcome measures, but there was no significant effect of the axis (WTR or ATR) of astigmatism (p > 0.05). Simulated bilateral astigmatism impaired children's performance on a range of academic-related outcome measures irrespective of the orientation of the astigmatism. These findings have

  6. Gamma and x radiation and thermal neutrons effects in lens solutions and the relation with proteins concentration

    International Nuclear Information System (INIS)

    Ramirez A, M.; Alarcon C, A.

    1996-01-01

    Radiation effects have been studied irradiating porcine lens solutions with doses which range between 52 Gy to 1042 Gy in the case of x-rays (30 kVp), 631 Gy to 4001 Gy in the case of 60 Co gamma rays and 314 Gy to 7596 Gy for thermal neutrons. The optics density time variation of solutions was determined using a Spectronic-501 spectrophotometer, and with this data an equation which describes the behavior in the mentioned cases was found. A phenomenological model is postulated which connects the optical time variation density increment macroscopic effect with proteins concentration in the crystalline lens obtaining relative biological effectiveness using the supra-molecular aggregate formation due to the denaturalization and destruction of lens proteins by radiation criteria. (authors). 5 refs., 3 figs

  7. Ultracold neutrons

    International Nuclear Information System (INIS)

    Steenstrup, S.

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

  8. Performative Identity as a Resource for Classroom Participation: Scientific Shane vs. Jimmy Neutron

    Science.gov (United States)

    Anderson, Kate T.; Zuiker, Steven J.

    2010-01-01

    This study introduces performative identity as a lens for understanding student participation in discursive classroom routines and potentials for fostering student agency and enhanced learning. We argue that student negotiation of performative identities can facilitate productive transformations of individual and group trajectories. This study…

  9. The Relation between Sustainable Innovation Strategy and Financial Performance Mediated By Environmental Performance

    Directory of Open Access Journals (Sweden)

    Hariyati Hariyati

    2015-06-01

    Full Text Available This study aims to examine the relationship of sustainable innovation strategy and financial performance through the mediation environmental performance. The hypothesis in this study is sustainable innovation strategy affect the financial performance which is mediated by environmental performance. This study is quantitative research in the explanatory level. The population of this study is all the manufacturer companies in East Java. The data is collected through questionnaire. The unit of analysis is a business unit. The respondent of this study is the manager of a business unit manufacturing company in East Java. The results showed that the environmental performance mediates partially the relation between sustainable innovation strategy and financial performance.

  10. Neutron structural biology

    Energy Technology Data Exchange (ETDEWEB)

    Niimura, Nobuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    Neutron diffraction provides an experimental method of directly locating hydrogen atoms in protein which play important roles in physiological functions. However, there are relatively few examples of neutron crystallography in biology since it takes a lot of time to collect a sufficient number of Bragg reflections due to the low flux of neutrons illuminating the sample. In order to overcome the flux problem, we have successfully developed the neutron IP, where the neutron converter, {sup 6}Li or Gd, was mixed with a photostimulated luminescence material on flexible plastic support. Neutron Laue diffraction 2A data from tetragonal lysozyme were collected for 10 days with neutron imaging plates, and 960 hydrogen atoms in the molecule and 157 bound water molecules were identified. These results explain the proposed hydrolysis mechanism of the sugar by the lysozyme molecule and that lysozyme is less active at pH7.0. (author)

  11. Neutron reflectivity

    Directory of Open Access Journals (Sweden)

    Cousin Fabrice

    2015-01-01

    Full Text Available The specular neutron reflectivity is a technique enabling the measurement of neutron scattering length density profile perpendicular to the plane of a surface or an interface, and thereby the profile of chemical composition. The characteristic sizes that are probed range from around 5 Å up 5000 Å. It is a scattering technique that averages information on the entire surface and it is therefore not possible to obtain information within the plane of the interface. The specific properties of neutrons (possibility of tuning the contrast by isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons makes it particularly interesting in the fields of soft matter, biophysics and magnetic thin films. This course is a basic introduction to the technique and does not address the magnetic reflectivity. It is composed of three parts describing respectively its principle and its formalism, the experimental aspects of the method (spectrometers, samples and two examples related to the materials for energy.

  12. Proposal of requirements for performance in Brazil for systems of external individual monitoring for neutrons applying the TLD-albedo technique

    International Nuclear Information System (INIS)

    Martins, Marcelo M.; Mauricio, Claudia L.P.; Pereira, Walsan W.; Fonseca, Evaldo S. da; Silva, Ademir X.

    2009-01-01

    This work presents a criteria and conditions proposal for the regulations in Brazil of individual monitoring systems for neutrons applying the albedo technique with thermoluminescent detectors. Tests are proposed for the characterization performance of the system based on the Regulation ISO 21909 and on the experience of the authors

  13. Procedure for measurement of anisotropy factor for neutron sources

    International Nuclear Information System (INIS)

    Creazolla, Prycylla Gomes

    2017-01-01

    Radioisotope neutron sources allow the production of reference fields for calibration of neutron detectors for radiation protection and analysis purposes. When the emission rate of these sources is isotropic, no correction is necessary. However, variations in source encapsulation and in the radioactive material concentration produce differences in its neutron emission rate, relative to the source axis, this effect is called anisotropy. In this study, is describe a procedure for measuring the anisotropy factor of neutron sources performed in the Laboratório de Metrologia de Neutrons (LN) using a Precision Long Counter (PLC) detector. A measurement procedure that takes into account the anisotropy factor of neutron sources contributes to solve some issues, particularly with respect to the high uncertainties associated with neutron dosimetry. Thus, a bibliographical review was carried out based on international standards and technical regulations specific to the area of neutron fields, and were later reproduced in practice by means of the procedure for measuring the anisotropy factor in neutron sources of the LN. The anisotropy factor is determined as a function of the angle of 90° in relation to the cylindrical axis of the source. This angle is more important due to its high use in measurements and also of its higher neutron emission rate if compared with other angles. (author)

  14. Spatial transformation abilities and their relation to later mathematics performance.

    Science.gov (United States)

    Frick, Andrea

    2018-04-10

    Using a longitudinal approach, this study investigated the relational structure of different spatial transformation skills at kindergarten age, and how these spatial skills relate to children's later mathematics performance. Children were tested at three time points, in kindergarten, first grade, and second grade (N = 119). Exploratory factor analyses revealed two subcomponents of spatial transformation skills: one representing egocentric transformations (mental rotation and spatial scaling), and one representing allocentric transformations (e.g., cross-sectioning, perspective taking). Structural equation modeling suggested that egocentric transformation skills showed their strongest relation to the part of the mathematics test tapping arithmetic operations, whereas allocentric transformations were strongly related to Numeric-Logical and Spatial Functions as well as geometry. The present findings point to a tight connection between early mental transformation skills, particularly the ones requiring a high level of spatial flexibility and a strong sense for spatial magnitudes, and children's mathematics performance at the beginning of their school career.

  15. Relating Standardized Visual Perception Measures to Simulator Visual System Performance

    Science.gov (United States)

    Kaiser, Mary K.; Sweet, Barbara T.

    2013-01-01

    Human vision is quantified through the use of standardized clinical vision measurements. These measurements typically include visual acuity (near and far), contrast sensitivity, color vision, stereopsis (a.k.a. stereo acuity), and visual field periphery. Simulator visual system performance is specified in terms such as brightness, contrast, color depth, color gamut, gamma, resolution, and field-of-view. How do these simulator performance characteristics relate to the perceptual experience of the pilot in the simulator? In this paper, visual acuity and contrast sensitivity will be related to simulator visual system resolution, contrast, and dynamic range; similarly, color vision will be related to color depth/color gamut. Finally, we will consider how some characteristics of human vision not typically included in current clinical assessments could be used to better inform simulator requirements (e.g., relating dynamic characteristics of human vision to update rate and other temporal display characteristics).

  16. Neutronic studies of the long life core concept: Part 1, Design and performance of 1000 MWe uranium oxide fueled low power density LMR cores

    International Nuclear Information System (INIS)

    Orechwa, Y.

    1987-04-01

    The parametric behavior of some key neutronic performance parameters for low power density LMR cores fueled with uranium oxide is investigated. The results are compared to reference homogeneous and heterogeneous cores with normal fuel management and Pu fueling. It can be concluded that with respect to minimizing the initial fissile mass and thereby economizing on the inventory costs and carrying charges, the superior neutron economy of the LMR fuel cycle is best exploited through normal fuel management with Pu recycling. In the once-through mode the LMR fuel cycle has disadvantages due to a higher fissile inventory and is not competitive with the LWR fuel cycle

  17. Evaluation of neutron dosimetry techniques for well-logging operations

    International Nuclear Information System (INIS)

    Cummings, F.M.; Haggard, D.L.; Endres, G.W.R.

    1985-07-01

    Neutron dose and energy spectral measurements from 241 AmBe and a 14 MeV neutron generator were performed at a well-logging laboratory. The measurement technique included the tissue equivalent proportional counter, multisphere, two types of remmeters and five types of personnel neutron dosimeters. Several source configurations were used to attempt to relate data to field situations. The results of the measurements indicated that the thermoluminescent albedo dosimeter was the most appropriate personnel neutron dosimeter, and that the most appropriate calibration source would be the source normally employed in the field with the calibration source being used in the unmoderated configuration. 7 refs., 35 figs., 14 tabs

  18. Measurements for the energy calibration of the TANSY neutron detectors

    International Nuclear Information System (INIS)

    Drozdowicz, K.; Hoek, M.; Aronsson, D.

    1990-05-01

    The report describes measurements performed for the energy calibration of the TANSY neutron detectors (two arrays of 16 detectors each one). The calibration procedure determines four calibration parameters for each detector. Results of the calibration measurements are given and test measurements are presented. A relation of the neutron detector calibration parameters to producer's data for the photomulipliers is analysed. Also the tests necessary during normal operation of the TANSY neutron spectrometer are elaborated (passive and active tests). A method how to quickly get the calibration parameters for a spare detector in an array of the neutron detectors is included

  19. Performance analysis of fusion nuclear-data benchmark experiments for light to heavy materials in MeV energy region with a neutron spectrum shifter

    International Nuclear Information System (INIS)

    Murata, Isao; Ohta, Masayuki; Miyamaru, Hiroyuki; Kondo, Keitaro; Yoshida, Shigeo; Iida, Toshiyuki; Ochiai, Kentaro; Konno, Chikara

    2011-01-01

    Nuclear data are indispensable for development of fusion reactor candidate materials. However, benchmarking of the nuclear data in MeV energy region is not yet adequate. In the present study, benchmark performance in the MeV energy region was investigated theoretically for experiments by using a 14 MeV neutron source. We carried out a systematical analysis for light to heavy materials. As a result, the benchmark performance for the neutron spectrum was confirmed to be acceptable, while for gamma-rays it was not sufficiently accurate. Consequently, a spectrum shifter has to be applied. Beryllium had the best performance as a shifter. Moreover, a preliminary examination of whether it is really acceptable that only the spectrum before the last collision is considered in the benchmark performance analysis. It was pointed out that not only the last collision but also earlier collisions should be considered equally in the benchmark performance analysis.

  20. Subjective performance evaluations and reciprocity in principal-agent relations

    DEFF Research Database (Denmark)

    Sebald, Alexander Christopher; Walzl, Markus

    2014-01-01

    . In contrast to existing models of reciprocity, we find that agents tend to sanction whenever the feedback of principals is below their subjective self-evaluations even if agents' pay-offs are independent of it. In turn, principals provide more positive feedback (relative to their actual performance assessment......We conduct a laboratory experiment with agents working on, and principals benefiting from, a real effort task in which the agents' performance can only be evaluated subjectively. Principals give subjective performance feedback to agents, and agents have an opportunity to sanction principals...... of the agent) if this does not affect their pay-off....

  1. The Budget-Related Antecedents of Job Performance

    Directory of Open Access Journals (Sweden)

    Emine Yilmaz Karakoc

    2016-04-01

    Full Text Available This study aims to investigate budget related antecedents of job performance of managers. For this purpose, relationships among budgetary participation, budget goal commitment, information sharing, and job performance of managers were examined. The sample consists of managers who are responsible from the budgets of their units in different private enterprises located in Turkey. Survey data was analyzed with confirmatory factor analyses and Structural Equation Modeling. Results indicate that budgetary participation has statistically significant and positive impact on job performance. It also positively affects budget goal commitment and information sharing. Budget goal commitment and information sharing have significant and positive impact on job performance. In addition, budget goal commitment positively affects information sharing of managers. Analyses also revealed that budget goal commitment and information sharing have partial mediation effect on the relationship between budgetary participation and job performance.

  2. Coupled neutronics/thermal-hydraulics analysis of a high-performance light-water reactor fuel assembly

    International Nuclear Information System (INIS)

    Waata, C.L.

    2006-07-01

    The use of water at supercritical pressure as coolant and moderator introduces a challenge in the design of a High-Performance Light-Water Reactor (HPLWR) fuel assembly. At supercritical pressure condition (P=25 MPa), the thermal-hydraulics behaviour of water differs strongly from that at sub-critical pressure due to a rapid variation of the thermal-physical properties across the pseudo-critical line. Due of the strong link between the water (moderation) and the neutron spectrum and subsequently the power distribution, a coupling of neutronics and thermal-hydraulics has become a necessity for reactor concepts operating at supercritical pressure condition. The effect of neutron moderation on the local parameters of thermal-hydraulics and vice-verse in a fuel assembly has to be considered for an accurate design analysis. In this study, the Monte Carlo N-Particle code (MCNP) and the sub-channel code STAFAS (Sub-channel Thermal-hydraulics Analysis of a Fuel Assembly under Supercritical conditions) have been coupled for the design analysis of a fuel assembly with supercritical water as coolant and moderator. Both codes are well known for complex geometry modelling. The MCNP code is used for neutronics analyses and for the prediction of power profiles of individual fuel rods. The sub-channel code STAFAS for the thermal-hydraulics analyses takes into account the coolant properties beyond the critical point as well as separate moderator channels. The coupling procedure is realized automatically. MCNP calculates the power distribution in each fuel rod, which is then transferred into STAFAS to obtain the corresponding thermal-hydraulic conditions in each sub-channel. The new thermal-hydraulic conditions are used to generate a new input deck for the next MCNP calculation. This procedure is repeated until a converged state is achieved. The coupled code system was tested on a proposed fuel assembly design of a HPLWR. An under-relaxation was introduced to achieve convergence

  3. Criterion for the engineering performance of carbon materials under neutron irradiation

    International Nuclear Information System (INIS)

    Virgil'ev, Yu.S.

    2002-01-01

    The criterion for the engineering performance and substation of its applicability to the reactor graphite are proposed. The complex indicator, representing the ratio of strength limits by compression and bending is proposed as the above criterion, characterizing the graphite quality. The growth of this criterion indicates the accumulation of large heterogeneities microcracks of technological or radiation character. The decrease in this indicator testifies to the growth of small heterogeneities, and consequently to the increase in the graphite engineering performance [ru

  4. Responses of commercially available neutron electronic personal dosemeters in neutron fields simulating workplaces at MOX fuel fabrication facilities

    International Nuclear Information System (INIS)

    Tsujimura, N.; Yoshida, T.; Takada, C.

    2011-01-01

    The authors investigated the performance of three commercially available electronic personal dosemeters (EPDs) in evaluating neutron dose equivalents and discussed their suitability to work environments in MOX fuel fabrication facilities. The EPDs selected for this study were NRY21 (Fuji Electric Systems), PDM-313 (Aloka) and DMC 2000 GN (MGP Instruments). All tests were conducted in moderated 252 Cf neutron fields with neutron spectral and dosimetric characteristics similar to those found in MOX fuel facilities. The test results revealed trends and the magnitude of response variations in relation to neutron spectral changes expected in work environments.

  5. Eurisol-DS Multi-MW target A proposal for improving overall performance in relation to the isotope yield

    CERN Document Server

    Samec, K; Kadi, Yacine; Rocca, Roberto; Kharoua, Cyril

    2008-01-01

    The Eurisol Design Study has been initiated by the European Commission to demonstrate the feasibility of a facility for producing large yields of exotic isotopes. At the core of the projected facility, the neutron source produces spallation neutrons from a proton beam impacting dense liquid metal. The neutrons emitted from the source are used to fission Uranium targets which, in turn, produce high yields of isotopes. This technical report summarises efforts to improve the overall performance of the planned facility, by optimising the neutron source and the disposition of the fission targets.

  6. EURISOL-DS Multi-MW Target. A proposal for improving overall performance in relation to the isotope yield

    CERN Document Server

    Karel Samec, Mats Lindroos, Yacine Kadi,Roberto Rocca, Cyril KharouaAB Dept. ATB

    The Eurisol Design Study has been initiated by the European Commission to demonstratethe feasibility of a facility for producing large yields of exotic isotopes.At the core of the projected facility, the neutron source produces spallation neutrons from aproton beam impacting dense liquid metal. The neutrons emitted from the source are usedto fission Uranium targets which, in turn, produce high yields of isotopes.This technical report summarises efforts to improve the overall performance of the plannedfacility, by optimising the neutron source and the disposition of the fission targets.

  7. Performance of the SciBar cosmic ray telescope (SciCRT) toward the detection of high-energy solar neutrons in solar cycle 24

    Science.gov (United States)

    Sasai, Yoshinori; Nagai, Yuya; Itow, Yoshitaka; Matsubara, Yutaka; Sako, Takashi; Lopez, Diego; Itow, Tsukasa; Munakata, Kazuoki; Kato, Chihiro; Kozai, Masayoshi; Miyazaki, Takahiro; Shibata, Shoichi; Oshima, Akitoshi; Kojima, Hiroshi; Tsuchiya, Harufumi; Watanabe, Kyoko; Koi, Tatsumi; Valdés-Galicia, Jose Francisco; González, Luis Xavier; Ortiz, Ernesto; Musalem, Octavio; Hurtado, Alejandro; Garcia, Rocio; Anzorena, Marcos

    2014-12-01

    We plan to observe solar neutrons at Mt. Sierra Negra (4,600 m above sea level) in Mexico using the SciBar detector. This project is named the SciBar Cosmic Ray Telescope (SciCRT). The main aims of the SciCRT project are to observe solar neutrons to study the mechanism of ion acceleration on the surface of the sun and to monitor the anisotropy of galactic cosmic-ray muons. The SciBar detector, a fully active tracker, is composed of 14,848 scintillator bars, whose dimension is 300 cm × 2.5 cm × 1.3 cm. The structure of the detector enables us to obtain the particle trajectory and its total deposited energy. This information is useful for the energy reconstruction of primary neutrons and particle identification. The total volume of the detector is 3.0 m × 3.0 m × 1.7 m. Since this volume is much larger than the solar neutron telescope (SNT) in Mexico, the detection efficiency of the SciCRT for neutrons is highly enhanced. We performed the calibration of the SciCRT at Instituto Nacional de Astrofisica, Optica y Electronica (INAOE) located at 2,150 m above sea level in Mexico in 2012. We installed the SciCRT at Mt. Sierra Negra in April 2013 and calibrated this detector in May and August 2013. We started continuous observation in March 2014. In this paper, we report the detector performance as a solar neutron telescope and the current status of the SciCRT.

  8. Background determination for the neutron-neutron scattering experiment at the reactor YAGUAR

    Energy Technology Data Exchange (ETDEWEB)

    Muzichka, A.Yu. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Furman, W.I. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Lychagin, E.V. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Krylov, A.R. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Nekhaev, G.V. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Sharapov, E.I. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Shvetsov, V.N. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Strelkov, A.V. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Levakov, B.G. [Russian Federal Nuclear Center-All-Russian Research Institute of Technical Physics, PO Box 245, 456770 Snezhinsk (Russian Federation); Lyzhin, A.E. [Russian Federal Nuclear Center-All-Russian Research Institute of Technical Physics, PO Box 245, 456770 Snezhinsk (Russian Federation); Chernukhin, Yu.I. [Russian Federal Nuclear Center-All-Russian Research Institute of Technical Physics, PO Box 245, 456770 Snezhinsk (Russian Federation); Kandiev, Ya.Z. [Russian Federal Nuclear Center-All-Russian Research Institute of Technical Physics, PO Box 245, 456770 Snezhinsk (Russian Federation); Howell, C.R. [Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Mitchell, G.E. [North Carolina State University, Raleigh, NC 27695-8202 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Crawford, B.E. [Gettysburg College, Box 405, Gettysburg, PA 17325 (United States); Stephenson, S.L. [Gettysburg College, Box 405, Gettysburg, PA 17325 (United States)]. E-mail: sstephen@gettysburg.edu; Tornow, W. [Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)

    2007-06-01

    The motivation and design is outlined for the experiment to measure the neutron-neutron singlet scattering length directly with thermal neutrons at the pulsed reactor YAGUAR. A statistical accuracy of 3% can be reached, though achieving the goal of an overall accuracy of 3-5% for the nn-scattering length depends on the background level. Possible sources of background are discussed in depth and the results of extensive modeling of the background are presented. Measurements performed at YAGUAR to test these background calculations are described. The experimental results indicate an anticipated background level up to 30% relative to the expected nn effect at the maximal energy burst of the reactor. The conclusion is made that the nn experiment at YAGUAR is feasible to produce the first directly measured value for the neutron-neutron scattering length.

  9. The Impact of Servitization Strategy on Relational Capital and Relational Performance: Evidences from China's Industrial Enterprises

    Institute of Scientific and Technical Information of China (English)

    SONG Hua; ZHANG Song-bo

    2014-01-01

    By identifying the characteristics of services management and the levels of specialty resources,the servitization strategy in the service supply chain management can be defined as the following three types,i.e.the business process oriented services,the technique application oriented services and the system integrated or packaged services.At the same time,it is found based on an empirical study of the data of China's enterprises that these strategies have different impact on relational capital and relational performance of the customers with different types of size.For large-scale enterprises,the business process oriented services and the technique application oriented services are significant factors impacting their relational capital and relational performance,while for SMEs,their relational capital and relational performance are impacted more by the technique application oriented services and the system integrated and packaged services.

  10. The Effect of Relational Constructs on Relationship Performance

    NARCIS (Netherlands)

    P.C. Verhoef (Peter); Ph.H.B.F. Franses (Philip Hans); J.C. Hoekstra (Janny)

    2000-01-01

    textabstractWe examine the effect of relational constructs, such as satisfaction, trust and commitment on relationship performance (that is, positive word-of-mouth communication and the margin provided by each customer) of customers of an insurance company. A central issue concerns the effect of

  11. The relation between breakfast skipping and school performance in adolescents

    NARCIS (Netherlands)

    Boschloo, Annemarie; Ouwehand, Carolijn; Dekker, Sanne; Lee, Nikki; De Groot, Renate; Krabbendam, Lydia; Jolles, Jelle

    2012-01-01

    Boschloo, A., Ouwehand, C., Dekker, S., Lee, N., De Groot, R., Krabbendam, L., & Jolles, J. (2012). The relation between breakfast skipping and school performance in adolescents. Mind, Brain, and Education, 6(2), 81-88. doi:10.1111/j.1751-228x.2012.01138.x

  12. Dynamic Incentive Effects of Relative Performance Pay: A Field Experiment

    NARCIS (Netherlands)

    J. Delfgaauw (Josse); A.J. Dur (Robert); J.A. Non (Arjan); W.J.M.I. Verbeke (Willem)

    2010-01-01

    textabstractWe conduct a field experiment among 189 stores of a retail chain to study dynamic incentive effects of relative performance pay. Employees in the randomly selected treatment stores could win a bonus by outperforming three comparable stores from the control group over the course of four

  13. Age-related decrements in cycling and running performance ...

    African Journals Online (AJOL)

    South African Journal of Sports Medicine ... This study examined age-related decrements in athletic performance during running and cycling activities. ... These findings establish a trend that there is 'accelerated' aging during running which can perhaps be attributed to the increased weight-bearing stress on the muscles ...

  14. 34 CFR 75.732 - Records related to performance.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Records related to performance. 75.732 Section 75.732 Education Office of the Secretary, Department of Education DIRECT GRANT PROGRAMS What Are the Administrative...) Determine progress in accomplishing project objectives; and (2) Revise those objectives, if necessary...

  15. Neutron Decay with PERC: a Progress Report

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  16. Nanodiamond Foils for H- Stripping to Support the Spallation Neutron Source (SNS) and Related Applications

    Energy Technology Data Exchange (ETDEWEB)

    Vispute, R D [Blue Wave Semiconductors; Ermer, Henry K [Blue Wave Semiconductors; Sinsky, Phillip [Blue Wave Semiconductors; Seiser, Andrew [Blue Wave Semiconductors; Shaw, Robert W [ORNL; Wilson, Leslie L [ORNL; Harris, Gary [Howard University; Piazza, Fabrice [Pontifica Universidad Catolica Madre y Maestra, Dominican Republic

    2013-01-01

    Thin diamond foils are needed in many particle accelerator experiments regarding nuclear and atomic physics, as well as in some interdisciplinary research. Particularly, nanodiamond texture is attractive for this purpose as it possesses a unique combination of diamond properties such as high thermal conductivity, mechanical strength and high radiation hardness; therefore, it is a potential material for energetic ion beam stripper foils. At the ORNL Spallation Neutron Source (SNS), the installed set of foils must be able to survive a nominal five-month operation period, without the need for unscheduled costly shutdowns and repairs. Thus, a single nanodiamond foil about the size of a postage stamp is critical to the entire operation of SNS and similar sources in U.S. laboratories and around the world. We are investigating nanocrystalline, polycrystalline and their admixture films fabricated using a hot filament chemical vapor deposition (HFCVD) system for H- stripping to support the SNS at Oak Ridge National Laboratory. Here we discuss optimization of process variables such as substrate temperature, process gas ratio of H2/Ar/CH4, substrate to filament distance, filament temperature, carburization conditions, and filament geometry to achieve high purity diamond foils on patterned silicon substrates with manageable intrinsic and thermal stresses so that they can be released as free standing foils without curling. An in situ laser reflectance interferometry tool (LRI) is used for monitoring the growth characteristics of the diamond thin film materials. The optimization process has yielded free standing foils with no pinholes. The sp3/sp2 bonds are controlled to optimize electrical resistivity to reduce the possibility of surface charging of the foils. The integrated LRI and HFCVD process provides real time information on the growth of films and can quickly illustrate growth features and control over film thickness. The results are discussed in the light of development

  17. Proficiency Testing by Interlaboratory Comparison Performed in 2010-2015 for Neutron Activation Analysis and Other Analytical Techniques

    International Nuclear Information System (INIS)

    2017-12-01

    The IAEA supports its Member States to increase the utilization of their research reactors. Small and medium sized reactors are mostly used for neutron activation analysis (NAA). Although the markets for NAA laboratories have been identified, demonstration of valid analytical results and organizational quality of the work process are preconditions for expanding the stakeholder community, particularly in commercial routine application of this powerful technique. The IAEA has implemented a new mechanism for supporting NAA laboratories in demonstrating their analytical performance by participation in proficiency testing schemes by interlaboratory comparison. This activity makes possible the identification of deviations and non-conformities, their causes and the process to implement effective approaches to eliminate them. Over 30 laboratories participated between 2010 and 2015 in consecutive proficiency tests organized by the IAEA in conjunction with the Wageningen Evaluating Programmes for Analytical Laboratories (WEPAL) to assess their analytical performances. This publication reports the findings and includes lessons learned of this activity. An attached CD-ROM contains many individual participating laboratory papers sharing their individual results and experience gained through this participation.

  18. Performance Evaluation of Java Based Object Relational Mapping Tools

    Directory of Open Access Journals (Sweden)

    Shoaib Mahmood Bhatti

    2013-04-01

    Full Text Available Object persistency is the hot issue in the form of ORM (Object Relational Mapping tools in industry as developers use these tools during software development. This paper presents the performance evaluation of Java based ORM tools. For this purpose, Hibernate, Ebean and TopLinkhave been selected as the ORM tools which are popular and open source. Their performance has been measured from execution point of view. The results show that ORM tools are the good option for the developers considering the system throughput in shorter setbacks and they can be used efficiently and effectively for performing mapping of the objects into the relational dominated world of database, thus creating a hope for a better and well dominated future of this technology.

  19. The age-related performance decline in ultraendurance mountain biking.

    Science.gov (United States)

    Haupt, Samuel; Knechtle, Beat; Knechtle, Patrizia; Rüst, Christoph Alexander; Rosemann, Thomas; Lepers, Romuald

    2013-01-01

    The age-related changes in ultraendurance performance have been previously examined for running and triathlon but not mountain biking. The aims of this study were (i) to describe the performance trends and (ii) to analyze the age-related performance decline in ultraendurance mountain biking in a 120-km ultraendurance mountain bike race the "Swiss Bike Masters" from 1995 to 2009 in 9,325 male athletes. The mean (±SD) race time decreased from 590 ± 80 min to 529 ± 88 min for overall finishers and from 415 ± 8 min to 359 ± 16 min for the top 10 finishers, respectively. The mean (±SD) age of all finishers significantly (P Bike Masters" appears to start earlier compared with other ultraendurance sports.

  20. Effect of yoga on academic performance in relation to stress

    Directory of Open Access Journals (Sweden)

    Kauts Amit

    2009-01-01

    Full Text Available Background: Academic performance is concerned with the quantity and quality of learning attained in a subject or group of subjects after a long period of instruction. Excessive stress hampers students′ performance. Improvement in academic performance and alertness has been reported in several yogic studies. Aims and Objectives: The main objective of the study was to assess the effect of yoga on academic performance in relation to stress. Materials and Methods: The study started with 800 adolescent students; 159 high-stress students and 142 low-stress students were selected on the basis of scores obtained through Stress Battery. Experimental group and control group were given pre test in three subjects, i.e., Mathematics, Science, and Social Studies. A yoga module consisting of yoga asanas, pranayama, meditation, and a value orientation program was administered on experimental group for 7 weeks. The experimental and control groups were post-tested for their performance on the three subjects mentioned above. Results: The results show that the students, who practiced yoga performed better in academics. The study further shows that low-stress students performed better than high-stress students, meaning thereby that stress affects the students′ performance.

  1. Relations between mental health team characteristics and work role performance.

    Science.gov (United States)

    Fleury, Marie-Josée; Grenier, Guy; Bamvita, Jean-Marie; Farand, Lambert

    2017-01-01

    Effective mental health care requires a high performing, interprofessional team. Among 79 mental health teams in Quebec (Canada), this exploratory study aims to 1) determine the association between work role performance and a wide range of variables related to team effectiveness according to the literature, and to 2) using structural equation modelling, assess the covariance between each of these variables as well as the correlation with other exogenous variables. Work role performance was measured with an adapted version of a work role questionnaire. Various independent variables including team manager characteristics, user characteristics, team profiles, clinical activities, organizational culture, network integration strategies and frequency/satisfaction of interactions with other teams or services were analyzed under the structural equation model. The later provided a good fit with the data. Frequent use of standardized procedures and evaluation tools (e.g. screening and assessment tools for mental health disorders) and team manager seniority exerted the most direct effect on work role performance. While network integration strategies had little effect on work role performance, there was a high covariance between this variable and those directly affecting work role performance among mental health teams. The results suggest that the mental healthcare system should apply standardized procedures and evaluation tools and, to a lesser extent, clinical approaches to improve work role performance in mental health teams. Overall, a more systematic implementation of network integration strategies may contribute to improved work role performance in mental health care.

  2. Skill-related performance in soccer: a systematic review

    Directory of Open Access Journals (Sweden)

    Aquino Rodrigo

    2017-12-01

    Full Text Available The aim of the study was to evaluate and organize systematically the available literature on skill-related performance in young and adult male soccer players in an attempt to identify the most common topics, ascertain the weaknesses, and elucidate the main contributions of the scientific papers on this issue. A systematic review of the Institute for Scientific Information (ISI Web of Knowledge database was performed in accordance with the Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA guidelines. The keywords ‘football’ and ‘soccer’ were used, each associated with the following terms: ‘technical analysis,’ ‘technical performance,’ ‘technical activity,’ ‘technical skill,’ ‘technical demands,’ ‘technical profiles,’ ‘technical characteristics,’ ‘technical actions,’ ‘technical scores,’ ‘technical ability,’ ‘motor skills,’ and ‘skill acquisition’. From the 2830 papers, only 60 were reviewed, of which 75% had been published in years 2011-2015 and 53.3% concerned professional or seniors players (above the U-20 category. Out of the 41 papers that analysed the skill-related performance in the match, 48.8% evaluated the performance in small-sided and conditioned games. Among the 27 papers that used validated instruments, 88.9% assessed technical actions outside the match context (e.g. dribbling, shooting tests. Future research should pay attention to the definition and classification of the skill-related variables under investigation in match context and propose tests for measured skill-related performance in soccer, considering that the representativeness task design allies the players’ possibilities of action to the situation of the match.

  3. Exploiting graph kernels for high performance biomedical relation extraction.

    Science.gov (United States)

    Panyam, Nagesh C; Verspoor, Karin; Cohn, Trevor; Ramamohanarao, Kotagiri

    2018-01-30

    Relation extraction from biomedical publications is an important task in the area of semantic mining of text. Kernel methods for supervised relation extraction are often preferred over manual feature engineering methods, when classifying highly ordered structures such as trees and graphs obtained from syntactic parsing of a sentence. Tree kernels such as the Subset Tree Kernel and Partial Tree Kernel have been shown to be effective for classifying constituency parse trees and basic dependency parse graphs of a sentence. Graph kernels such as the All Path Graph kernel (APG) and Approximate Subgraph Matching (ASM) kernel have been shown to be suitable for classifying general graphs with cycles, such as the enhanced dependency parse graph of a sentence. In this work, we present a high performance Chemical-Induced Disease (CID) relation extraction system. We present a comparative study of kernel methods for the CID task and also extend our study to the Protein-Protein Interaction (PPI) extraction task, an important biomedical relation extraction task. We discuss novel modifications to the ASM kernel to boost its performance and a method to apply graph kernels for extracting relations expressed in multiple sentences. Our system for CID relation extraction attains an F-score of 60%, without using external knowledge sources or task specific heuristic or rules. In comparison, the state of the art Chemical-Disease Relation Extraction system achieves an F-score of 56% using an ensemble of multiple machine learning methods, which is then boosted to 61% with a rule based system employing task specific post processing rules. For the CID task, graph kernels outperform tree kernels substantially, and the best performance is obtained with APG kernel that attains an F-score of 60%, followed by the ASM kernel at 57%. The performance difference between the ASM and APG kernels for CID sentence level relation extraction is not significant. In our evaluation of ASM for the PPI task, ASM

  4. CVD polycrystalline diamond. A novel neutron detector and applications

    International Nuclear Information System (INIS)

    Mongkolnavin, R.

    1998-01-01

    Chemical Vapour Deposition (CVD) Polycrystalline Diamond film has been investigated as a low noise sensor for beta particles, gammas and neutrons using High Energy Physics technologies. Its advantages and disadvantages have been explored in comparison with other particle detectors such as silicon detector and other plastic scintillators. The performance and characteristic of the diamond detector have been fully studied and discussed. These studies will lead to a better understanding of how CVD diamonds perform as a detector and how to improve their performance under various conditions. A CVD diamond detector model has been proposed which is an attempt to explain the behaviour of such an extreme detector material. A novel neutron detector is introduced as a result of these studies. A good thermal and fast neutron detector can be fabricated with CVD diamond with new topologies. This detector will perform well without degradation in a high neutron radiation environment, as diamond is known to be radiation hard. It also offers better neutrons and gammas discrimination for high gamma background applications compared to other semiconductor detectors. A full simulation of the detector has also been done using GEANT, a Monte-Carlo simulation program for particle detectors. Simulation results show that CVD diamond detectors with this novel topology can detect neutrons with great directionality. Experimental work has been done on this detector in a nuclear reactor environment and accelerator source. A novel neutron source which offers a fast pulse high-energy neutrons has also been studied. With this detector, applications in neutron spectrometer for low-Z material have been pursued with various neutron detection techniques. One of these is a low-Z material identification system. The system has been designed and simulated for contraband luggage interrogation using the detector and the novel neutron source. Also other neutron related applications have been suggested. (author)

  5. Neutron thermalization in light water

    International Nuclear Information System (INIS)

    Abbate, M.J.; Lolich, J.V.

    1975-05-01

    Investigations related to neutron thermalization in light water have been made. Neutron spectra under quasi-infinite-medium conditions have been measured by the time-of-flight technique and calculations were performed with different codes. Through the use of improved experimental techniques and the best known calculational techniques available, the known discrepancies between experimentals and theoretical values were below from 40% to 16%. The present disagreement is believed to be due the scattering model used (ENDF-GASKET, based on the modified Haywood II frequency spectra), that shows to be very satisfactory for poisoned light water cases. Moreover, previous experiments were completed and differential, integral and pulse-source experimental techniques were improved. Also a second step of a neutron and reactor calculation system was completed. (author)

  6. Development of Neutron Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Hee; Lee, J. S.; Seong, B. S. (and others)

    2007-06-15

    Neutron spectrometers which are used in the basic researches such as physics, chemistry and materials science and applied in the industry were developed at the horizontal beam port of HANARO reactor. In addition, the development of core components for neutron scattering and the upgrade of existing facilities are also performed. The vertical neutron reflectometer was fabricated and installed at ST3 beam port. The performance test of the reflectometer was completed and the reflectometer was opened to users. The several core parts and options were added in the polarized neutron spectrometer. The horizontal neutron reflectometer from Brookhaven National Laboratory was moved to HANARO and installed, and the performance of the reflectometer was examined. The HIPD was developed and the performance test was completed. The base shielding for TAS was fabricated. The soller collimator, Cu mosaic monochromator, Si BPC monochromator and position sensitive detector were developed and applied in the neutron spectrometer as part of core component development activities. In addition, the sputtering machine for mirror device are fabricated and the neutron mirror is made using the sputtering machine. The FCD was upgraded and the performance of the FCD are improved over the factor of 10. The integration and upgrade of the neutron detection system were also performed.

  7. Plasticization effect of C60 on the fast dynamics of polystyrene and related polymers: an incoherent neutron scattering study

    International Nuclear Information System (INIS)

    Sanz, Alejandro; Ruppel, Markus; Cabral, Joao T; Douglas, Jack F

    2008-01-01

    We utilize inelastic incoherent neutron scattering (INS) to quantify how fullerenes affect the 'fast' molecular dynamics of a family of polystyrene related macromolecules. In particular, we prepared bulk nanocomposites of (hydrogenous and ring-deuterated) polystyrene and poly(4-methyl styrene) using a rapid precipitation method where the C 60 relative mass fraction ranged from 0% to 4%. Elastic window scan measurements, using a high resolution (0.9 μeV) backscattering spectrometer, are reported over a wide temperature range (2-450 K). Apparent Debye-Waller (DW) factors 2 >, characterizing the mean-square amplitude of proton displacements, are determined as a function of temperature, T. We find that the addition of C 60 to these polymers leads to a progressive increase in 2 > relative to the pure polymer value over the entire temperature range investigated, where the effect is larger for larger nanoparticle concentration. This general trend seems to indicate that the C 60 nanoparticles plasticize the fast (∼10 -15 s) local (∼1 A) dynamics of these polymer glasses. Generally, we expect nanoparticle additives to affect polymer dynamics in a similar fashion to thin films in the sense that the high interfacial area may cause both a speeding up and slowing down of the glass state dynamics depending on the polymer-surface interaction

  8. Basic research of neutron radiography using cold neutron beam

    International Nuclear Information System (INIS)

    Oda, Masahiro; Tamaki, Masayoshi; Tasaka, Kanji

    1995-01-01

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

  9. Determination of relative krypton fission product yields from 14 MeV neutron induced fission of 238U at the National Ignition Facility.

    Science.gov (United States)

    Edwards, E R; Cassata, W S; Velsko, C A; Yeamans, C B; Shaughnessy, D A

    2016-11-01

    Precisely-known fission yield distributions are needed to determine a fissioning isotope and the incident neutron energy in nuclear security applications. 14 MeV neutrons from DT fusion at the National Ignition Facility induce fission in depleted uranium contained in the target assembly hohlraum. The fission yields of Kr isotopes (85m, 87, 88, and 89) are measured relative to the cumulative yield of 88 Kr and compared to previously tabulated values. The results from this experiment and England and Rider are in agreement, except for the 85m Kr/ 88 Kr ratio, which may be the result of incorrect nuclear data.

  10. Occupational Congruence and Personal Task-Related Attributes: How Do They Relate to Work Performance?

    Science.gov (United States)

    Tziner, Aharon; Meir, Elchanan I.; Segal, Hila

    2002-01-01

    Data from 359 military officers (measures of personality, ability, and congruence) and supervisor and peer performance ratings were analyzed. Personality and person-environment fit were related to performance. Extroverts and those whose interests were congruent with their work environment tended to receive higher ratings. (Contains 41 references.)…

  11. The relative biological effectiveness of fractionated doses of fast neutrons (42 MeV sub d yields Be ) for normal tissues. Pt. 3; Effects on lung function

    Energy Technology Data Exchange (ETDEWEB)

    Rezvani, M.; Hopewell, J.W.; Robbins, M.E.C.; Hamlet, R. (Churchill Hospital, Oxford (UK)); Barnes, D.W.H.; Sansom, J.M.; Adams, P.J.V. (Medical Research Council, Harwell (UK). Radiobiological Research Unit)

    1990-11-01

    The effect of single and fractionated doses of fast neutrons (42 MeV{sub d{yields}Bc}) on the early and late radiation responses of the pig lung have been assessed by the measurement of changes in lung function using a {sup 133}Xe washout technique. The results obtained for irradiation schedules with fast neutrons have been compared with those after photon irradiation. There was no statistically significant difference between the values for the relative biological effectiveness (RBE) for the early and late radiation response of the lung. The RBE of the neutron beam increased with decreasing size of dose/fraction with an upper limit value of 4.39 {plus minus} 0.94 for infinitely small X-ray doses per fraction. (author).

  12. [Performance of Slovak hospitals as related to Porter's generic strategies].

    Science.gov (United States)

    Hlavacka, S; Bacharova, L; Rusnakova, V; Wagner, R

    2001-01-01

    Porter's generic strategies characterize organizations in terms of their competitiveness, and are related to the performance of the organization. The aim of this study was to analyze the Porter's generic strategies and their effect on performance in the context of the Slovak hospital industry. Acute care hospitals with more than 30 beds were included into the study. National institutes providing specialized service were excluded from the study. Strategy and performance were evaluated on the basis of self-reported questionnaires, completed by chief administrators of hospitals (total 76 completed questionnaires were obtained, out of 81 distributed, i.e. 94% response rate). The cluster analysis was used for the identification of strategic orientation. Performance differences across strategic groups were tested using multivariate analysis of covariance (MANCOVA). The hierarchical cluster analysis uncovered a four-group taxonomy of hospitals: the group "Focused Cost Leadership" included 33% of hospitals, the group "Stuck-in-the middle" 49%, the group "Wait and See" 13% and the group "Cost leadership" 5%. Significant differences in performance were related to the Porter's pure, or hybrid strategies, respectively. In terms of industry evolution, the Slovak hospital industry could be characterized as fragmented, having a large number of small and medium size mainly state owned hospitals, with absence of market leaders, and with high exit barriers (mainly social and political) that hold back consolidation. (Tab. 1, Ref. 35.).

  13. Research of psychological characteristics and performance relativity of operators

    International Nuclear Information System (INIS)

    Fang Xiang; He Xuhong; Zhao Bingquan

    2008-01-01

    Based on the working tasks of an operator being taken into full consideration in this paper, on the one hand the table of measuring psychological characteristics is designed through the selection of special dimensions; on the other hand the table of performance appraisal is drafted through the choice of suitable standards of an operator. The paper analyzes the results of two aspects, sets relevant nuclear power plant operators as the research objective, and obtains the psychological characteristics and performance relativity of operators. The research can be as important and applied reference for the selection, evaluation and use of operators

  14. A Neutron Study for Phonon Dispersion Relations in HgTe

    DEFF Research Database (Denmark)

    Kepa, H.; Gebicki, W.; Giebultowicz, T.

    1980-01-01

    Dispersion relations for acoustic phonons in mercury telluride in three high symmetry directions [111], [110] and [001] are presented. The eleven-parameter rigid-ion model is fitted to the experimental data....

  15. Assessment of the impact of neutronic/thermal-hydraulic coupling on the design and performance of nuclear reactors for space propulsion

    International Nuclear Information System (INIS)

    Aithal, S.M.; Aldemir, T.; Vafai, K.

    1994-01-01

    A series of studies has been performed to investigate the potential impact of the coupling between neutronics and thermal hydraulics on the design and performance assessment of solid core reactors for nuclear thermal space propulsion, using the particle bed reactor (PBR) concept as an example system. For a given temperature distribution in the reactor, the k eff and steady-state core power distribution are obtained from three-dimensional, continuous energy Monte Carlo simulations using the MCNP code. For a given core power distribution, determination of the temperature distribution in the core and hydrogen-filled annulus between the reflector and pressure vessel is based on a nonthermal equilibrium analysis. The results show that a realistic estimation of fuel, core size, and control requirements for PBRs using hydrogenous moderators, as well as optimization of the overall engine design, may require coupled neutronic/thermal-hydraulic studies. However, it may be possible to estimate the thermal safety margins and propellant exit temperatures based on power distributions obtained from neutronic calculations at room temperature. The results also show that, while variation of the hydrogen flow rate in the annulus has been proposed as a partial control mechanism for PBRs, such control mechanism may not be feasible for PBRs with high moderator-to-fuel ratios and hence soft core neutron spectra

  16. Soil-plant relation in Cuban sugar cane by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Diaz Riso, O.; Griffith Martinez, J.

    1996-01-01

    This paper shows the result of soil-plant relation in samples from Cuban sugar canes of different soil types and cane varieties, using the INAA from thermal reactor. The behaviour of minor and trace elements in sugar cane leaves is uniform and independent of sugar cane variety or type of soil. The soil-plant relation shows four principal groups of micro elements, according to their absorption by the plant

  17. Neutron resonance transmission spectroscopy with high spatial and energy resolution at the J-PARC pulsed neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Tremsin, A.S., E-mail: ast@ssl.berkeley.edu [University of California at Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States); Shinohara, T.; Kai, T.; Ooi, M. [Japan Atomic Energy Agency, 2–4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Kamiyama, T.; Kiyanagi, Y.; Shiota, Y. [Hokkaido University, Kita 13 Nishi 8 Kita-ku, Sapporo-shi, Hokkaido 060-8628 (Japan); McPhate, J.B.; Vallerga, J.V.; Siegmund, O.H.W. [University of California at Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States); Feller, W.B. [NOVA Scientific, Inc., 10 Picker Rd., Sturbridge, MA 01566 (United States)

    2014-05-11

    The sharp variation of neutron attenuation at certain energies specific to particular nuclides (the lower range being from ∼1 eV up to ∼1 keV), can be exploited for the remote mapping of element and/or isotope distributions, as well as temperature probing, within relatively thick samples. Intense pulsed neutron beam-lines at spallation sources combined with a high spatial, high-timing resolution neutron counting detector, provide a unique opportunity to measure neutron transmission spectra through the time-of-flight technique. We present the results of experiments where spatially resolved neutron resonances were measured, at energies up to 50 keV. These experiments were performed with the intense flux low background NOBORU neutron beamline at the J-PARC neutron source and the high timing resolution (∼20 ns at epithermal neutron energies) and spatial resolution (∼55 µm) neutron counting detector using microchannel plates coupled to a Timepix electronic readout. Simultaneous element-specific imaging was carried out for several materials, at a spatial resolution of ∼150 µm. The high timing resolution of our detector combined with the low background beamline, also enabled characterization of the neutron pulse itself – specifically its pulse width, which varies with neutron energy. The results of our measurements are in good agreement with the predicted results for the double pulse structure of the J-PARC facility, which provides two 100 ns-wide proton pulses separated by 600 ns, broadened by the neutron energy moderation process. Thermal neutron radiography can be conducted simultaneously with resonance transmission spectroscopy, and can reveal the internal structure of the samples. The transmission spectra measured in our experiments demonstrate the feasibility of mapping elemental distributions using this non-destructive technique, for those elements (and in certain cases, specific isotopes), which have resonance energies below a few keV, and with lower

  18. Overview on neutron beam industry-focused strategic research in Malaysia

    International Nuclear Information System (INIS)

    Abdul Aziz Mohamed; Razali Kassim; Abdul Jalil Abdul Hamid; Azali Muhammad; Muhammad Rawi Mohd Zain; Azhar Azmi

    2002-01-01

    The TRIGA MARK II research reactor (RTP) at the Malaysian Institute for Nuclear Technology Research (MINT) was commissioned in July 1982. RTP is a 1 MW steady state reactor which being used for reactor training and research related to neutron. Since then various works have been performed to utilise the neutrons produced from this steady state reactor. Projects undertaken are the development and utilization of the neutron radiography (myNR) and small angle neutron scattering (mySANS) facilities. This poster highlights the recent status the above neutron beam facilities and their application in materials science and technology research and education. (Author)

  19. Quality control and performance evaluation of k0-based neutron activation analysis at the Portuguese research reactor

    International Nuclear Information System (INIS)

    Dung, H.M.; Freitas, M.C.; Blaauw, M.; Almeida, S.M.; Dionisio, I.; Canha, N.H.

    2010-01-01

    The quality control (QC) and performance evaluation for the k 0 -based neutron activation analysis (k 0 -NAA) at the Portuguese research reactor (RPI) has been developed with the intention of using the method to meet the demands of trace element analysis for the applications in environmental, epidemiological and nutritional studies amongst others. The QC and performance evaluation include the following aspects: (1) estimation of the overall/combined standard uncertainty from the primary uncertainty sources; (2) validation of the method using a synthetic multi-element standard (SMELS); and (3) analysis of the certified reference materials from the National Institute of Standards and Technology (USA): NIST-SRM-1633a and NIST-SRM-1648 and the reference material from the International Atomic Energy Agency: IAEA-RM-336, for the purpose of controlling the overall accuracy and precision of the analytical results. The obtained results revealed that the k 0 -NAA method established at the RPI was fit for the purpose. The overall/combined standard uncertainty was estimated for elements of interest in the intended applications. The laboratory's analytical results as compared to the assigned values with the bias were less than 12% for most elements, except for a few elements which biased within 13-18%. The u-score values for most elements were less than |1.64|, except for Co, La and Ti within |1.64|-|1.96| and Sc, Cr, K and Sb within |1.96|-|2.58|. The NIST-1633a was also analyzed over 14 months for the purpose of evaluating the reproducibility of the method. The quality factors of k 0 -NAA established at RPI were evaluated, proving that the method meets the requirements of trace element analysis, which is also considering the method's performance for which the k 0 -NAA affords a specific, rapid and convenient capability for the intended applications.

  20. Natural Composites: Cellulose Fibres and the related Performance of Composites

    DEFF Research Database (Denmark)

    Lilholt, Hans; Madsen, Bo

    2014-01-01

    Biobased materials are becoming of increasing interest as potential structural materials for the future. A useful concept in this context is the fibre reinforcement of materials by stiff and strong fibres. The biobased resources can contribute with cellulose fibres and biopolymers. This offers th...... in stiffness, on the packing ability of cellulose fibres and the related maximum fibre volume fraction in composites, on the moisture sorption of cellulose fibres and the related mass increase and (large) hygral strains induced, and on the mechanical performance of composites....

  1. Behavior of structural and target materials irradiated in spallation neutron environments

    International Nuclear Information System (INIS)

    Stubbins, J.F.; Wechsler, M.; Borden, M.

    1995-01-01

    This paper describes considerations for selection of structural and target materials for accelerator-driven neutron sources. Due to the operating constraints of proposed accelerator-driven neutron sources, the criteria for selection are different than those commonly applied to fission and fusion systems. Established irradiation performance of various alloy systems is taken into account in the selection criteria. Nevertheless, only limited materials performance data are available which specifically related to neutron energy spectra anticipated for spallation sources

  2. Behavior of structural and target materials irradiated in spallation neutron environments

    Energy Technology Data Exchange (ETDEWEB)

    Stubbins, J.F. [Univ. of Illinois, Urbana, IL (United States); Wechsler, M. [North Carolina State Univ., Raleigh, NC (United States); Borden, M. [Los Alamos National Laboratory, NM (United States)] [and others

    1995-10-01

    This paper describes considerations for selection of structural and target materials for accelerator-driven neutron sources. Due to the operating constraints of proposed accelerator-driven neutron sources, the criteria for selection are different than those commonly applied to fission and fusion systems. Established irradiation performance of various alloy systems is taken into account in the selection criteria. Nevertheless, only limited materials performance data are available which specifically related to neutron energy spectra anticipated for spallation sources.

  3. Comparison of the performance of different instruments in the stray neutron field around the CERN Proton Synchrotron.

    Science.gov (United States)

    Aza, Eleni; Caresana, Marco; Cassell, Christopher; Colombo, Valeria; Damjanovic, Sanja; Gilardoni, Simone; Manessi, Giacomo Paolo; Pangallo, Michel; Perrin, Daniel; Silari, Marco

    2014-10-01

    This paper discusses an intercomparison campaign carried out in several locations around the CERN Proton Synchrotron. The locations were selected in order to perform the measurements in different stray field conditions. Various neutron detectors were employed: ionisation chambers, conventional and extended range rem counters, both commercial and prototype ones, including a novel instrument called LUPIN, specifically conceived to work in pulsed fields. The attention was focused on the potential differences in the instrument readings due to dead-time losses that are expected to affect most commercial units. The results show that the ionisation chambers and LUPIN agree well with the expected H*(10) values, as derived from FLUKA simulations, showing no relevant underestimations even in strongly pulsed fields. On the contrary, the dead-time losses of the other rem counters induced an underestimation in pulsed fields that was more important for instruments characterised by a higher dead time. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. EURISOL-DS Multi-MW Target Comparative Neutronic Performance of the Baseline Configuration vs. the Hg-Jet Option

    CERN Document Server

    Herrera-Martínez, A

    2006-01-01

    This technical report summarises the comparative study between several design options for the Multi-MW target station performed within Task #2 of the European Isotope Separation On-Line Radioactive Ion Beam Facility Design Study (EURISOL DS) [1]. Previous analyses were carried out, using the Monte Carlo code FLUKA [2], to determine optimal values for relevant parameters in the target design [3] and to analyse a preliminary Multi-MW target assembly configuration [4]. The second report showed that the aimed fission rates, i.e. ~1015 fissions/s, could be achieved with such a configuration. Nevertheless, a preliminary study of the target assembly integration [5] suggested reducing some of the dimensions. Moreover, the yields of specific isotopes have yet to be assessed and compared to other target configurations. This note presents a detailed comparison of the baseline configuration and the Hg-jet option, in terms of primary and neutron distribution, power densities and fission product yields. A scaled-down versi...

  5. Characteristics of Fabricated SiC Neutron Detectors for Neutron Flux Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Han Soo; Ha, Jang Ho; Park, Se Hwan; Lee, Kyu Hong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Cheol Ho [Hanyang University, Seoul (Korea, Republic of)

    2011-05-15

    An SPND (Self-powered Neutron Detector) is commonly used for neutron detection in NPP (Nuclear Power Plant) by virtue of un-reactivity for gamma-rays. But it has a drawback, which is that it cannot detect neutrons in real time due to beta emissions (about > 48 s) after reactions between neutrons and {sup 103}Rh in an SPND. And Generation IV reactors such as MSR (Molten-salt reactor), SFR (Sodium-cooled fast reactor), and GFR (Gas-cooled fast reactor) are designed to compact size and integration type. For GEN IV reactor, neutron monitor also must be compact-sized to apply such reactor easily and much more reliable. The wide band-gap semiconductors such as SiC, AlN, and diamond make them an attractive alternative in applications in harsh environments by virtue of the lower operating voltage, faster charge-collection times compared with gas-filled detectors, and compact size.1) In this study, two PIN-type SiC semiconductor neutron detectors, which are for fast neutron detection by elastic and inelastic scattering SiC atoms and for thermal neutron detection by charged particle emissions of 6LiF reaction, were designed and fabricated for NPP-related applications. Preliminary tests such as I-V and alpha response were performed and neutron responses at ENF in HANARO research reactor were also addressed. The application feasibility of the fabricated SiC neutron detector as an in-core neutron monitor was discussed

  6. Phase space representation of neutron monitor count rate and atmospheric electric field in relation to solar activity in cycles 21 and 22.

    Science.gov (United States)

    Silva, H G; Lopes, I

    Heliospheric modulation of galactic cosmic rays links solar cycle activity with neutron monitor count rate on earth. A less direct relation holds between neutron monitor count rate and atmospheric electric field because different atmospheric processes, including fluctuations in the ionosphere, are involved. Although a full quantitative model is still lacking, this link is supported by solid statistical evidence. Thus, a connection between the solar cycle activity and atmospheric electric field is expected. To gain a deeper insight into these relations, sunspot area (NOAA, USA), neutron monitor count rate (Climax, Colorado, USA), and atmospheric electric field (Lisbon, Portugal) are presented here in a phase space representation. The period considered covers two solar cycles (21, 22) and extends from 1978 to 1990. Two solar maxima were observed in this dataset, one in 1979 and another in 1989, as well as one solar minimum in 1986. Two main observations of the present study were: (1) similar short-term topological features of the phase space representations of the three variables, (2) a long-term phase space radius synchronization between the solar cycle activity, neutron monitor count rate, and potential gradient (confirmed by absolute correlation values above ~0.8). Finally, the methodology proposed here can be used for obtaining the relations between other atmospheric parameters (e.g., solar radiation) and solar cycle activity.

  7. The Relative Age Effect and Its Influence on Academic Performance.

    Directory of Open Access Journals (Sweden)

    Juan-José Navarro

    Full Text Available The policy of school organisation for grouping students in the same academic year is based on date of birth. The differences in the experiences and maturation of older students involve a relatively better performance in academic settings, which is known as the relative age effect (RAE. This effect is more important the younger the student is. The goal of this study is to identify the connections of influence that RAE, socioeconomic status (SES, and type of institution have on academic performance in a school population of eighth graders.The study is based on a population-based, representative sample of 15,234 8th graders (50.4% female; average age = 13.61 years in the 2011 National System of Quality Assessment in Education Survey (SIMCE from Chile. The SIMCE for global academic performance consists of 4 tests: reading, mathematics, social studies, and science. All tests consist of multiple-choice and closed questions. In addition, in order to have the information of general academic performance, an extra variable expressing the average score of each student was created. Also, the SIMCE includes additional variables for the evaluation process such as SES or type of school. Students were assigned to one of five age groups in terms of date of birth (G1, G2, G3, G4, and G5, in which students belonging to G1 are the oldest and students belonging to G5 are the youngest.The results achieved in the structural equation modelling indicate a good global fit. Individual relationships show significant effects of the three variables observed on academic performance, although SES received the highest values. The influence of RAE took place both in the full sample and sub-samples composed according to the SES and academic performance, showing higher values for students with lower scores. Although the influence of RAE decreases when SES is controlled, its effect is still significant and contributes to additionally explain the performance.The RAE remains, even

  8. The Relative Age Effect and Its Influence on Academic Performance.

    Science.gov (United States)

    Navarro, Juan-José; García-Rubio, Javier; Olivares, Pedro R

    2015-01-01

    The policy of school organisation for grouping students in the same academic year is based on date of birth. The differences in the experiences and maturation of older students involve a relatively better performance in academic settings, which is known as the relative age effect (RAE). This effect is more important the younger the student is. The goal of this study is to identify the connections of influence that RAE, socioeconomic status (SES), and type of institution have on academic performance in a school population of eighth graders. The study is based on a population-based, representative sample of 15,234 8th graders (50.4% female; average age = 13.61 years) in the 2011 National System of Quality Assessment in Education Survey (SIMCE) from Chile. The SIMCE for global academic performance consists of 4 tests: reading, mathematics, social studies, and science. All tests consist of multiple-choice and closed questions. In addition, in order to have the information of general academic performance, an extra variable expressing the average score of each student was created. Also, the SIMCE includes additional variables for the evaluation process such as SES or type of school. Students were assigned to one of five age groups in terms of date of birth (G1, G2, G3, G4, and G5), in which students belonging to G1 are the oldest and students belonging to G5 are the youngest. The results achieved in the structural equation modelling indicate a good global fit. Individual relationships show significant effects of the three variables observed on academic performance, although SES received the highest values. The influence of RAE took place both in the full sample and sub-samples composed according to the SES and academic performance, showing higher values for students with lower scores. Although the influence of RAE decreases when SES is controlled, its effect is still significant and contributes to additionally explain the performance. The RAE remains, even with residual

  9. Neutron structural biology

    International Nuclear Information System (INIS)

    Niimura, Nobuo

    1999-01-01

    Neutron structural biology will be one of the most important fields in the life sciences which will interest human beings in the 21st century because neutrons can provide not only the position of hydrogen atoms in biological macromolecules but also the dynamic molecular motion of hydrogen atoms and water molecules. However, there are only a few examples experimentally determined at present because of the lack of neutron source intensity. Next generation neutron source scheduled in JAERI (Performance of which is 100 times better than that of JRR-3M) opens the life science of the 21st century. (author)

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  11. Neutron capture studies of {sup 206}Pb at a cold neutron beam

    Energy Technology Data Exchange (ETDEWEB)

    Schillebeeckx, P.; Kopecky, S.; Quetel, C.R.; Tresl, I.; Wynants, R. [Institute for Reference Materials and Measurements, European Commission, Joint Research Centre, Geel (Belgium); Belgya, T.; Szentmiklosi, L. [Institute for Energy Security and Environmental Safety, Centre for Energy Research, Budapest (Hungary); Borella, A. [Institute for Reference Materials and Measurements, European Commission, Joint Research Centre, Geel (Belgium); SCK CEN, Mol (Belgium); Mengoni, A. [Nuclear Data Section, International Atomic Energy Agency (IAEA), Wagramerstrasse 5, PO Box 100, Vienna (Austria); Agenzia Nazionale per le Nuove Tecnologie, l' Energia e lo Sviluppo Economico Sostenibile (ENEA), Bologna (Italy)

    2013-11-15

    Gamma-ray transitions following neutron capture in {sup 206}Pb have been studied at the cold neutron beam facility of the Budapest Neutron Centre using a metallic sample enriched in {sup 206}Pb and a natural lead nitrate powder pellet. The measurements were performed using a coaxial HPGe detector with Compton suppression. The observed {gamma} -rays have been incorporated into a decay scheme for neutron capture in {sup 206}Pb. Partial capture cross sections for {sup 206}Pb(n, {gamma}) at thermal energy have been derived relative to the cross section for the 1884 keV transition after neutron capture in {sup 14}N. From the average crossing sum a total thermal neutron capture cross section of 29{sup +2}{sub -1} mb was derived for the {sup 206}Pb(n, {gamma}) reaction. The thermal neutron capture cross section for {sup 206}Pb has been compared with contributions due to both direct capture and distant unbound s-wave resonances. From the same measurements a thermal neutron-induced capture cross section of (649 {+-} 14) mb was determined for the {sup 207}Pb(n, {gamma}) reaction. (orig.)

  12. Neutron activation studies on JET

    International Nuclear Information System (INIS)

    Loughlin, M.J.; Forrest, R.A.; Edwards, J.E.G.

    2001-01-01

    Extensive neutron transport calculations have been performed to determine the neutron spectrum at a number of points throughout the JET torus hall. The model has been bench-marked against a set of foil activation measurements which were activated during an experimental campaign with deuterium/tritium plasmas. The model can predict the neutron activation of the foils on the torus hall walls to within a factor of three for reactions with little sensitivity to thermal neutrons. The use of scandium foils with and without a cadmium thermal neutron absorber was a useful monitor of the thermal neutron flux. Conclusions regarding the usefulness of other foils for benchmarking the calculations are also given

  13. Dieting and food cue-related working memory performance

    Directory of Open Access Journals (Sweden)

    Adrian Meule

    2016-12-01

    Full Text Available Executive functioning (e.g., working memory is tightly intertwined with self-regulation. For example, food cue-elicited craving has been found to impair working memory performance. Furthermore, current dieters have been found to show lower working memory performance than non-dieters. Recent research, however, suggests that it is crucial to consider dieting success in addition to current dieting status or restrained eating in order to reveal cognitive mechanisms that are associated with successful eating-related self-regulation. The current study investigated food cue-related working memory performance as a function of dieting status and dieting success in female students. Participants performed an n-back task with pictures of food and neutral objects. Reaction time in response to food pictures was slower than in response to neutral pictures, whereas omission errors did not differ between picture types. Current food craving was increased after performing the food block, but not after the neutral block. There was an indirect effect of current dieting status on higher food craving after the food block, which was mediated by slower reaction time to food vs. neutral pictures. Furthermore, higher dieting success was associated with fewer omission errors in the food vs. neutral block in current dieters. There were no relationships of restrained eating with current food craving and task performance. Results further highlight the need to differentiate between successful and unsuccessful dieting in addition to current dieting status or restrained eating when examining possible mechanisms of overeating or successful restraint. Although palatable food cues induce food craving regardless of dieting success, they may boost executive functioning in successful dieters, which helps them to overcome these temptations.

  14. Dieting and Food Cue-Related Working Memory Performance.

    Science.gov (United States)

    Meule, Adrian

    2016-01-01

    Executive functioning (e.g., working memory) is tightly intertwined with self-regulation. For example, food cue-elicited craving has been found to impair working memory performance. Furthermore, current dieters have been found to show lower working memory performance than non-dieters. Recent research, however, suggests that it is crucial to consider dieting success in addition to current dieting status or restrained eating in order to reveal cognitive mechanisms that are associated with successful eating-related self-regulation. The current study investigated food cue-related working memory performance as a function of dieting status and dieting success in female students. Participants performed an n -back task with pictures of food and neutral objects. Reaction time in response to food pictures was slower than in response to neutral pictures, whereas omission errors did not differ between picture types. Current food craving was increased after performing the food block, but not after the neutral block. There was an indirect effect of current dieting status on higher food craving after the food block, which was mediated by slower reaction time to food vs. neutral pictures. Furthermore, higher dieting success was associated with fewer omission errors in the food vs. neutral block in current dieters. There were no relationships of restrained eating with current food craving and task performance. Results further highlight the need to differentiate between successful and unsuccessful dieting in addition to current dieting status or restrained eating when examining possible mechanisms of overeating or successful restraint. Although palatable food cues induce food craving regardless of dieting success, they may boost executive functioning in successful dieters, which helps them to overcome these temptations.

  15. Rapid MCNP simulation of DNA double strand break (DSB) relative biological effectiveness (RBE) for photons, neutrons, and light ions.

    Science.gov (United States)

    Stewart, Robert D; Streitmatter, Seth W; Argento, David C; Kirkby, Charles; Goorley, John T; Moffitt, Greg; Jevremovic, Tatjana; Sandison, George A

    2015-11-07

    To account for particle interactions in the extracellular (physical) environment, information from the cell-level Monte Carlo damage simulation (MCDS) for DNA double strand break (DSB) induction has been integrated into the general purpose Monte Carlo N-particle (MCNP) radiation transport code system. The effort to integrate these models is motivated by the need for a computationally efficient model to accurately predict particle relative biological effectiveness (RBE) in cell cultures and in vivo. To illustrate the approach and highlight the impact of the larger scale physical environment (e.g. establishing charged particle equilibrium), we examined the RBE for DSB induction (RBEDSB) of x-rays, (137)Cs γ-rays, neutrons and light ions relative to γ-rays from (60)Co in monolayer cell cultures at various depths in water. Under normoxic conditions, we found that (137)Cs γ-rays are about 1.7% more effective at creating DSB than γ-rays from (60)Co (RBEDSB  =  1.017) whereas 60-250 kV x-rays are 1.1 to 1.25 times more efficient at creating DSB than (60)Co. Under anoxic conditions, kV x-rays may have an RBEDSB up to 1.51 times as large as (60)Co γ-rays. Fission neutrons passing through monolayer cell cultures have an RBEDSB that ranges from 2.6 to 3.0 in normoxic cells, but may be as large as 9.93 for anoxic cells. For proton pencil beams, Monte Carlo simulations suggest an RBEDSB of about 1.2 at the tip of the Bragg peak and up to 1.6 a few mm beyond the Bragg peak. Bragg peak RBEDSB increases with decreasing oxygen concentration, which may create opportunities to apply proton dose painting to help address tumor hypoxia. Modeling of the particle RBE for DSB induction across multiple physical and biological scales has the potential to aid in the interpretation of laboratory experiments and provide useful information to advance the safety and effectiveness of hadron therapy in the treatment of cancer.

  16. Calibration Of A 14 MeV Neutron Generator With Reference To NBS-1

    International Nuclear Information System (INIS)

    Heimbach, Craig R.

    2011-01-01

    NBS-1 is the US national neutron reference source. It has a neutron emission rate (June 1961) of 1.257x10 6 n/s 1,2,3 with an uncertainty of 0.85%(k = 1). Neutron emission-rate calibrations performed at the National Institute of Standards and Technology (NIST) are made in comparison to this source, either directly or indirectly. To calibrate a commercial 14 MeV neutron generator, NIST performed a set of comparison measurements to evaluate the neutron output relative to NBS-1. The neutron output of the generator was determined with an uncertainty of about 7%(k = 1). The 15-hour half-life of one of the reactions used also makes possible off-site measurements. Consideration is given to similar calibrations for a 2.5 MeV neutron generator.

  17. Measuring the relative performance of stock market using TOPSIS

    Directory of Open Access Journals (Sweden)

    Abolfazl Danaei

    2013-01-01

    Full Text Available For many years, investors used some basic financial ratios to measure the relative performance of various active industries based on two-digit ISIC classification. However, direct implementation of basic financial figures may not be practical in today's business environment since investors face with different criteria. The proposed model of this paper uses Technique for Order Preference by Similarity to Ideal Solution (TOPSIS to compare 37 various industries based on different financial figures. We gather the necessary data over the period of 2009-2010 from Tehran Stock Exchange and investigate the data in two stages. In the first stage, we perform fundamental analysis to select the most appropriate firms and the in the second stage, we use TOPSIS to rank selected firms based on different criteria. The results of the study confirm that information and communication technology, which is one of the biggest firms in this exchange is considered as the best option (relative ranking 0.88 in two years followed by some Cement industry (with relative ranking of 0.26 in 2009 and 0.19 in 2010 and oil refinery units (with relative ranking of 0.23 in 2009 and 0.19 in 2010. The figure also shows that other firms maintain low ratios varied from 0.23 to 0.01. The lowest industry ranking belongs to marine industry.

  18. Development of highly effective neutron shields and neutron absorbing materials

    International Nuclear Information System (INIS)

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

    1993-01-01

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

  19. Neutronic performance of a fusion-fission hybrid reactor designed for fuel enrichment for LWRs

    International Nuclear Information System (INIS)

    Yapici, H.; Baltacioglu, E.

    1997-01-01

    In this study, the breeding performance of a fission hybrid reactor was analyzed to provide fissile fuel for Light Water Reactors (LWR) as an alternative to the current methods of gas diffusion and gas centrifuge. LWR fuel rods containing UO 2 or ThO 2 fertile material were located in the fuel zone of the blanket and helium gas or Flibe (Li 2 BeF 4 ) fluid was used as coolant. As a result of the analysis, according to fusion driver (D,T and D,D) and the type of coolant the enrichment of 3%-4% were achieved for operation periods of 12 and 36 months in case of fuel rods containing UO 2 , respectively and for operation periods of 18 and 48 months in case of fuel rods containing ThO 2 , respectively. Depending on the type of fusion driver, coolant and fertile fuel, varying enrichments of between 3% and 8.9% were achieved during operation period of four years

  20. High performance 3D neutron transport on peta scale and hybrid architectures within APOLLO3 code

    International Nuclear Information System (INIS)

    Jamelot, E.; Dubois, J.; Lautard, J-J.; Calvin, C.; Baudron, A-M.

    2011-01-01

    APOLLO3 code is a common project of CEA, AREVA and EDF for the development of a new generation system for core physics analysis. We present here the parallelization of two deterministic transport solvers of APOLLO3: MINOS, a simplified 3D transport solver on structured Cartesian and hexagonal grids, and MINARET, a transport solver based on triangular meshes on 2D and prismatic ones in 3D. We used two different techniques to accelerate MINOS: a domain decomposition method, combined with an accelerated algorithm using GPU. The domain decomposition is based on the Schwarz iterative algorithm, with Robin boundary conditions to exchange information. The Robin parameters influence the convergence and we detail how we optimized the choice of these parameters. MINARET parallelization is based on angular directions calculation using explicit message passing. Fine grain parallelization is also available for each angular direction using shared memory multithreaded acceleration. Many performance results are presented on massively parallel architectures using more than 103 cores and on hybrid architectures using some tens of GPUs. This work contributes to the HPC development in reactor physics at the CEA Nuclear Energy Division. (author)

  1. Neutron reflectometry

    International Nuclear Information System (INIS)

    Van Well, A.A.

    1999-01-01

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

  2. Performance test results of noninvasive characterization of Resource Conservation and Recovery Act surrogate waste by prompt gamma neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gehrke, R.J.; Streier, G.G.

    1997-03-01

    During FY-96, a performance test was carried out with funding from the Mixed Waste Focus Area (MWFA) of the Department of Energy (DOE) to determine the noninvasive elemental assay capabilities of commercial companies for Resource Conservation and Recovery Act (RCRA) metals present in 8-gal drums containing surrogate waste. Commercial companies were required to be experienced in the use of prompt gamma neutron activation analysis (PGNAA) techniques and to have a prototype assay system with which to conduct the test assays. Potential participants were identified through responses to a call for proposals advertised in the Commerce Business Daily and through personal contacts. Six companies were originally identified. Two of these six were willing and able to participate in the performance test, as described in the test plan, with some subsidizing from the DOE MWFA. The tests were conducted with surrogate sludge waste because (1) a large volume of this type of waste awaits final disposition and (2) sludge tends to be somewhat homogeneous. The surrogate concentrations of the above RCRA metals ranged from {approximately} 300 ppm to {approximately} 20,000 ppm. The lower limit was chosen as an estimate of the expected sensitivity of detection required by noninvasive, pretreatment elemental assay systems to be of value for operational and compliance purposes and to still be achievable with state-of-the-art methods of analysis. The upper limit of {approximately} 20,000 ppm was chosen because it is the opinion of the author that assay above this concentration level is within current state-of-the-art methods for most RCRA constituents. This report is organized into three parts: Part 1, Test Plan to Evaluate the Technical Status of Noninvasive Elemental Assay Techniques for Hazardous Waste; Part 2, Participants` Results; and Part 3, Evaluation of and Comments on Participants` Results.

  3. Performance test results of noninvasive characterization of Resource Conservation and Recovery Act surrogate waste by prompt gamma neutron activation analysis

    International Nuclear Information System (INIS)

    Gehrke, R.J.; Streier, G.G.

    1997-03-01

    During FY-96, a performance test was carried out with funding from the Mixed Waste Focus Area (MWFA) of the Department of Energy (DOE) to determine the noninvasive elemental assay capabilities of commercial companies for Resource Conservation and Recovery Act (RCRA) metals present in 8-gal drums containing surrogate waste. Commercial companies were required to be experienced in the use of prompt gamma neutron activation analysis (PGNAA) techniques and to have a prototype assay system with which to conduct the test assays. Potential participants were identified through responses to a call for proposals advertised in the Commerce Business Daily and through personal contacts. Six companies were originally identified. Two of these six were willing and able to participate in the performance test, as described in the test plan, with some subsidizing from the DOE MWFA. The tests were conducted with surrogate sludge waste because (1) a large volume of this type of waste awaits final disposition and (2) sludge tends to be somewhat homogeneous. The surrogate concentrations of the above RCRA metals ranged from ∼ 300 ppm to ∼ 20,000 ppm. The lower limit was chosen as an estimate of the expected sensitivity of detection required by noninvasive, pretreatment elemental assay systems to be of value for operational and compliance purposes and to still be achievable with state-of-the-art methods of analysis. The upper limit of ∼ 20,000 ppm was chosen because it is the opinion of the author that assay above this concentration level is within current state-of-the-art methods for most RCRA constituents. This report is organized into three parts: Part 1, Test Plan to Evaluate the Technical Status of Noninvasive Elemental Assay Techniques for Hazardous Waste; Part 2, Participants' Results; and Part 3, Evaluation of and Comments on Participants' Results

  4. Neutron nuclear physics under the neutron science project

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-11-01

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

  5. Introduction to neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Lattimer, James M. [Dept. of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States)

    2015-02-24

    Neutron stars contain the densest form of matter in the present universe. General relativity and causality set important constraints to their compactness. In addition, analytic GR solutions are useful in understanding the relationships that exist among the maximum mass, radii, moments of inertia, and tidal Love numbers of neutron stars, all of which are accessible to observation. Some of these relations are independent of the underlying dense matter equation of state, while others are very sensitive to the equation of state. Recent observations of neutron stars from pulsar timing, quiescent X-ray emission from binaries, and Type I X-ray bursts can set important constraints on the structure of neutron stars and the underlying equation of state. In addition, measurements of thermal radiation from neutron stars has uncovered the possible existence of neutron and proton superfluidity/superconductivity in the core of a neutron star, as well as offering powerful evidence that typical neutron stars have significant crusts. These observations impose constraints on the existence of strange quark matter stars, and limit the possibility that abundant deconfined quark matter or hyperons exist in the cores of neutron stars.

  6. Neutron interference by division of wave front

    International Nuclear Information System (INIS)

    Klein, A.G.; Kearney, P.D.; Opat, G.I.; Cimmimo, A.

    1981-01-01

    The highly successful perfect cyrstal neutron interferometer of the type first developed by Bonse and Rauch exhibits interference by amplitude division. It relies on dynamical Bragg diffraction in a highly perfect single crystal to provide the beamsplitting. This type of interferometer, topologically analogous to the Nach-Zehnder interferometer of classical optics, has been employed in a variety of interesting experiments using thermal neutrons. Its shortcomings, however, are its extreme sensitivity to mechanical and thermal disturbances, and its applicability only to wavelegths shorter than the Bragg cutoff (6.27 Angstrom in silicon). The authors discuss a novel type of neutron interferometer which was constructed and tested employing a split cylindrical zone plate with neutrons of 20 Angstrom wavelength. Its performance and relative merits are discussed

  7. The Los Alamos Intense Neutron Source

    International Nuclear Information System (INIS)

    Nebel, R.A.; Barnes, D.C.; Bollman, R.; Eden, G.; Morrison, L.; Pickrell, M.M.; Reass, W.

    1997-01-01

    The Intense Neutron Source (INS) is an Inertial Electrostatic Confinement (IEC) fusion device presently under construction at Los Alamos National Laboratory. It is designed to produce 10 11 neutrons per second steady-state using D-T fuel. Phase 1 operation of this device will be as a standard three grid IEC ion focus device. Expected performance has been predicted by scaling from a previous IEC device. Phase 2 operation of this device will utilize a new operating scheme, the Periodically Oscillating Plasma Sphere (POPS). This scheme is related to both the Spherical Reflect Diode and the Oscillating Penning Trap. With this type of operation the authors hope to improve plasma neutron production to about 10 13 neutrons/second

  8. Music-related reward responses predict episodic memory performance.

    Science.gov (United States)

    Ferreri, Laura; Rodriguez-Fornells, Antoni

    2017-12-01

    Music represents a special type of reward involving the recruitment of the mesolimbic dopaminergic system. According to recent theories on episodic memory formation, as dopamine strengthens the synaptic potentiation produced by learning, stimuli triggering dopamine release could result in long-term memory improvements. Here, we behaviourally test whether music-related reward responses could modulate episodic memory performance. Thirty participants rated (in terms of arousal, familiarity, emotional valence, and reward) and encoded unfamiliar classical music excerpts. Twenty-four hours later, their episodic memory was tested (old/new recognition and remember/know paradigm). Results revealed an influence of music-related reward responses on memory: excerpts rated as more rewarding were significantly better recognized and remembered. Furthermore, inter-individual differences in the ability to experience musical reward, measured through the Barcelona Music Reward Questionnaire, positively predicted memory performance. Taken together, these findings shed new light on the relationship between music, reward and memory, showing for the first time that music-driven reward responses are directly implicated in higher cognitive functions and can account for individual differences in memory performance.

  9. Analysis of the radiation related morbidity observed in a randomized trial of neutron therapy for bladder cancer

    International Nuclear Information System (INIS)

    Duncan, W.; Williams, J.R.; Kerr, G.R.; Arnott, S.J.; Quilty, P.M.; Rodger, A.; MacDougall, R.H.; Jack, W.J.

    1986-01-01

    This report is an analysis of the morbidity in the bladder and bowel observed in a randomized trial of d(15)+Be neutrons versus megavoltage photons in the treatment of bladder cancer. Acute reactions in the bladder and bowel were significantly worse after photon therapy. Of the patients treated with photons 45.7% had severe reactions in the bladder compared with 10.6% after neutron therapy (p less than 0.001). Severe acute bowel reactions were observed in 8.5% of the patients after photon therapy compared with 3.8% after neutron therapy (p less than 0.05). Late reactions were significantly worse after neutrons. Severe late reactions in the bladder were seen in 58.5% of patients after neutron therapy and in 40.5% after photon therapy (p less than 0.05). In the bowel they were observed in 53.3% of patients after neutron therapy compared with 8% after photon therapy (p less than 0.0001). The disparity in the degree of early and late complications makes assessment of RBE values difficult. It is estimated that for bladder morbidity the RBE value, for photon dose fractions of 2.75 Gy, is less than 3.3 for early reactions and equal to 3.4 for late effects. The respective RBE values for early and late effects in the bowel are less than 3.4 and 3.8

  10. Muons, neutrons and superconductivity

    International Nuclear Information System (INIS)

    Aeppli, G.; Risoe National Lab., Roskilde

    1988-01-01

    The principles of the neutron scattering and muon spin relaxation (μSR) techniques and their applications to studies of superconductors are described briefly. μSR and neutron scattering work on magnetic correlations in superconductors and materials directly related to superconductors are reviewed. (orig.)

  11. Neutron dosimetry for the TFTR Lithium-Blanket-Module program

    International Nuclear Information System (INIS)

    Harker, Y.D.; Tsang, F.Y.; Caffrey, A.J.; Homeyer, W.G.; Engholm, B.A.

    1981-01-01

    The Tokamak Fusion Test Reactor (TFTR) Lithium Blanket Module (LBM) program is a first-of-a-kind neutronics experiment involving a prototypical fusion reactor blanket module with a distributed neutron source from the plasma of the TFTR at Princeton Plasma Physics Laboratory. The objectives of the LBM program are: (1) to test the capabilities of neutron transport codes when applied to fusion test reactor blanket conditions, and (2) to obtain tritium breeding performance data on a typical design concept of a fusion-reactor blanket. This paper addresses the issues relative to the measurement of neutron fields in the LBM, presents the results of preliminary design studies concerning neutron measurements and also presents the results of blanket mockup experiments performed at the Idaho National Engineering Laboratory

  12. Neutron recognition in the LAND detector for large neutron multiplicity

    Energy Technology Data Exchange (ETDEWEB)

    Pawlowski, P., E-mail: piotr.pawlowski@ifj.edu.pl [Institute of Nuclear Physics, PAN, Radzikowskiego 152, 31-342 Krakow (Poland); Brzychczyk, J. [Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Krakow (Poland); Leifels, Y.; Trautmann, W. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Adrich, P. [National Centre for Nuclear Research, PL-00681 Warsaw (Poland); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Aumann, T. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Bacri, C.O. [Institut de Physique Nucleaire, IN2P3-CNRS et Universite, F-91406 Orsay (France); Barczyk, T. [Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Krakow (Poland); Bassini, R. [Istituto di Scienze Fisiche, Universita degli Studi and INFN, I-20133 Milano (Italy); Bianchin, S. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Boiano, C. [Istituto di Scienze Fisiche, Universita degli Studi and INFN, I-20133 Milano (Italy); Boretzky, K. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Boudard, A. [IRFU/SPhN, CEA/Saclay, F-91191 Gif-sur-Yvette (France); Chbihi, A. [GANIL, CEA et IN2P3-CNRS, F-14076 Caen (France); Cibor, J.; Czech, B. [Institute of Nuclear Physics, PAN, Radzikowskiego 152, 31-342 Krakow (Poland); De Napoli, M. [Dipartimento di Fisica e Astronomia-Universita and INFN-CT and LNS, I-95123 Catania (Italy); and others

    2012-12-01

    The performance of the LAND neutron detector is studied. Using an event-mixing technique based on one-neutron data obtained in the S107 experiment at the GSI laboratory, we test the efficiency of various analytic tools used to determine the multiplicity and kinematic properties of detected neutrons. A new algorithm developed recently for recognizing neutron showers from spectator decays in the ALADIN experiment S254 is described in detail. Its performance is assessed in comparison with other methods. The properties of the observed neutron events are used to estimate the detection efficiency of LAND in this experiment.

  13. Relative Age Affects Marathon Performance in Male and Female Athletes

    OpenAIRE

    Connick, Mark J.; Beckman, Emma M.; Tweedy, Sean M.

    2015-01-01

    Marathon runners are ranked in 5-year age groups. However the extent to which 5-year groupings facilitates equitable competition has not been evaluated. The aim of this study was to evaluate the effect of relative age in male and female marathon running. Marathon finishing times for the top ten male (aged 20-69 years) and female athletes (aged 20-64 years) were obtained from the 2013 New York and Chicago marathons. Intra-class and inter-class validity were evaluated by comparing performances ...

  14. The effect of performance related pay in employment services

    DEFF Research Database (Denmark)

    Sofie Johansen, Ann; Holm, Anders; Rosdahl, Anders

    This paper investigates the effects of performance-related pay (PRP) in Danish local employment administration on unemployed social clients’ employment outcomes. PRP implies here that employees in the employment administration are rewarded each time a social client gets a job. There are different...... schemes involved in the programme – schemes with collective payoffs and schemes with private payoffs and schemes with monetary payoffs and non-monetary payoffs, such as training activities. The main conclusion is that PRP seems to promote employment chances of social clients. Especially it seems that PRP...

  15. Aphysiologic performance on dynamic posturography in work-related patients.

    Science.gov (United States)

    Larrosa, F; Durà, M J; Menacho, J; González-Sabaté, L; Cordón, A; Hernández, A; García-Ibáñez, L

    2013-01-01

    It has been suggested that malingering should be suspected in patients suffering from dizziness or imbalance and who had a potential gain associated with insurance and worker's compensation claims. This study aimed to assess and compare the prevalence of aphysiologic performance on computerized dynamic posturography (CDP) in patients with the potential for secondary gain using a retrospective review of two groups of patients: work-related patients referred for dizziness and/or imbalance (Group 1) were compared against a group of patients with complaints of dizziness or imbalance, who had no history of work-related injury, or litigation procedures (Group 2). CDP and videonystagmography (VNG) were carried out in all patients. The Sensory Organization Test summaries were scored as normal, aphysiologic, or vestibular using the scoring method published by Cevette et al. in Otolaryngol Head Neck Surg 112:676-688 (1995). 24 out of 88 (27%) patients had aphysiologic CDP in Group 1 and 9 out of 51 (18%) in Group 2 but these differences were not significant (p > 0.05). Definite signs of vestibular dysfunction were found in 12 out of 24 (50%) of patients with aphysiologic performance in Group 1 although the presence of VNG abnormalities was significantly higher (p = 0.005) in Group 2. The hypothesis that the occupational group could show a significantly higher rate of aphysiologic results than a control group is not confirmed. Furthermore, VNG abnormalities were found in 50% of the work-related cases with non organic sway patterns. These results suggest that patient's complaints should be considered genuine in work-related cases and due caution exercised when evaluating aphysiologic CDP patterns.

  16. Thermal-hydraulic performance of a water-cooled tungsten-rod target for a spallation neutron source

    International Nuclear Information System (INIS)

    Poston, D.I.

    1997-08-01

    A thermal-hydraulic (T-H) analysis is conducted to determine the feasibility and limitations of a water-cooled tungsten-rod target at powers of 1 MW and above. The target evaluated has a 10-cm x 10-cm cross section perpendicular to the beam axis, which is typical of an experimental spallation neutron source - both for a short-pulse spallation source and long-pulse spallation source. This report describes the T-H model and assumptions that are used to evaluate the target. A 1-MW baseline target is examined, and the results indicate that this target should easily handle the T-H requirements. The possibility of operating at powers >1 MW is also examined. The T-H design is limited by the condition that the coolant does not boil (actual limits are on surface subcooling and wall heat flux); material temperature limits are not approached. Three possible methods of enhancing the target power capability are presented: reducing peak power density, altering pin dimensions, and improving coolant conditions (pressure and temperature). Based on simple calculations, it appears that this target concept should have little trouble reaching the 2-MW range (from a purely T-H standpoint), and possibly much higher powers. However, one must keep in mind that these conclusions are based solely on thermal-hydraulics. It is possible, and perhaps likely, that target performance could be limited by structural issues at higher powers, particularly for a short-pulse spallation source because of thermal shock issues

  17. Neutron Skins and Neutron Stars

    OpenAIRE

    Piekarewicz, J.

    2013-01-01

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

  18. Measurement of 237Np fission rate ratio relative to 235U fission rate in cores with various thermal neutron spectrum at the Kyoto University Critical Assembly

    International Nuclear Information System (INIS)

    Unesaki, Hironobu; Shiroya, Seiji; Iwasaki, Tomohiko; Fujiwara, Daisuke; Kitada, Takanori; Kuroda, Mitsuo; Kohashi, Akio; Kato, Takeshi; Ikeuchi, Yoshitaka

    2000-01-01

    Integral measurements of 237 Np fission rate ratio relative to 235 U fission rate have been performed at Kyoto University Citrical Assembly. The fission rates have been measured using the back-to back type double fission chamber at five thermal cores with different H/ 235 U ratio so that the neutron spectra of the cores were systematically varied. The measured fission rate ratio per atom was 0.00439 to 0.0298, with a typical uncertainty of 2 to 3%. The measured data were compared with the calculated results using SRAC/TWOTRAN and MVP based on JENDL-3.2, which gave the averaged C/E values of 0.93 and 0.95, respectively. Obtained results of C/E using 237 Np cross sections from JENDL-3/2, ENDF/B-VI.5 and JEF2.2 show that the latter two gave smaller results than JENDL-3.2 by about 4%, which clearly reflects the discrepancy in the evaluated cross section among the libraries. This difference arises from both fast fission and resonance region. Although further improvement is recommended, 237 Np fission cross section in JENDL-3.2 is considered to be superior to those in the other libraries and can be adopted for use in design calculations for minor actinide transmutation system using thermal reactors with prediction precision of 237 Np fission rate with in 10%. (author)

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

    Science.gov (United States)

    Blue, Thomas E; Yanch, Jacquelyn C

    2003-01-01

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

  20. Factors related to the performance of Specialized Dental Care Centers

    Directory of Open Access Journals (Sweden)

    Flávia Christiane de Azevedo Machado

    2015-04-01

    Full Text Available The Specialized Dental Care Centers (SDCC have the mission to expand access to public medium complexity dental care and support the primary health care actions at this level of complexity. However, it is necessary to ensure the quality of services and to evaluate such services continuously to identify weaknesses and strengths that support the processes of leadership/management. Nevertheless, there is a dearth of studies on the assessment of oral health in specialized care that may indicate which factors should be investigated. Therefore, this integrated literature review sought to explore the plethora of publications on the evaluation of SDCC in the LILACS and MEDLINE data bases in October 2013 to identify factors possibly related to the performance of such health services. Thus, 13 references were included in this review pointing to forms of organization and management of work processes related to the creation of healthcare networks (operation of regulation centers and setting up of health consortiums. They include the contextual characteristics of the places where SDCCs are located (population size, Family Health Strategy coverage, Municipal Human Development Index, governance, governing capacity were factors that influenced the SDCCs performance.

  1. Neutrons in biology

    International Nuclear Information System (INIS)

    Funahashi, Satoru; Niimura, Nobuo.

    1993-01-01

    The start of JRR-3M in 1990 was a great epoch to the neutron scattering research in Japan. Abundant neutron beam generated by the JRR-3M made it possible to widen the research field of neutron scattering in Japan. In the early days of neutron scattering, biological materials were too difficult object to be studied by neutrons not only because of their complexity but also because of the strong incoherent scattering by hydrogen. However, the remarkable development of the recent neutron scattering and its related sciences, as well as the availability of higher flux, has made the biological materials one of the most attractive subjects to be studied by neutrons. In early September 1992, an intensive workshop titled 'Neutrons in Biology' was held in Hitachi City by making use of the opportunity of the 4th International Conference on Biophysics and Synchrotron Radiation (BSR92) held in Tsukuba. The workshop was organized by volunteers who are eager to develop the researches in this field in Japan. Numbers of outstanding neutron scattering biologists from U.S., Europe and Asian countries met together and enthusiastic discussions were held all day long. The editors believe that the presentations at the workshop were so invaluable that it is absolutely adequate to put them on record as an issue of JAERI-M and to make them available for scientists to refer to in order to further promote the research in the future. (author)

  2. Strategic communication related to academic performance: Evidence from China.

    Science.gov (United States)

    Zhao, Li; Chen, Lulu; He, Luwei; Heyman, Gail D

    2017-09-01

    We examined a range of forms of strategic communication relevant to academic performance among 151 seventh- and eleventh-grade adolescents in China. Participants were asked to rate the frequency of their engagement of strategic communication and to evaluate the possible motives for each strategy. The most commonly adopted strategy was to give a vague response about one's own performance, and the predominant motives for strategic communication were the desires to outcompete others, to be prosocial, and to be modest. Males were more likely than females to focus on gaining social approval, and eleventh graders were more likely than seventh graders to focus on being prosocial and modest when engaging in strategic communication. These findings provide insight into the development of strategic communication beyond Western culture. Statement of contribution What is already known on this subject? Adolescents in the West often hide their effort to appear more competent or to gain social acceptance. Little is known about other communication strategies related to academic performance. Little is known about the development of these strategies in non-Western samples. What does this study add? We show that in China, as in Western cultures, children often engage in strategic communication. We demonstrate links between different forms of strategic communication and specific motives. We demonstrate that strategic communication can be motivated by outcompeting others, by being prosocial, and by being modest. © 2017 The British Psychological Society.

  3. Use of pulsed neutron logging to evaluate perforation washing

    International Nuclear Information System (INIS)

    Dimon, C.A.

    1986-01-01

    This invention relates to the use of pulsed neutron logging techniques before and after perforation washing operations are performed to evaluate the degree of success of the perforation washing operations. Well logging operations of a type designed to respond to the difference between a formation immediately behind the well sheath and voids in the formation are performed both before and after the perforation washing operation. differences between the two resulting logs are then indicative of voids created by perforation washing. In a preferred embodiment, pulsed neutron logging is used as the logging technique, while a weighted brine having a high absorption cross section to pulsed neutrons is used as the perforation washing fluid

  4. Priming performance-related concerns induces task-related mind-wandering.

    Science.gov (United States)

    Jordano, Megan L; Touron, Dayna R

    2017-10-01

    Two experiments tested the hypothesis that priming of performance-related concerns would (1) increase the frequency of task-related mind-wandering (i.e., task-related interference; TRI) and (2) decrease task performance. In each experiment, sixty female participants completed an operation span task (OSPAN) containing thought content probes. The task was framed as a math task for those in a condition primed for math-related stereotype threat and as a memory task for those in a control condition. In both studies, women whose performance-related concerns were primed via stereotype threat reported more TRI than women in the control. The second experiment used a more challenging OSPAN task and stereotype primed women also had lower math accuracy than controls. These results support the "control failures×current concerns" framework of mind-wandering, which posits that the degree to which the environmental context triggers personal concerns influences both mind-wandering frequency and content. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Neutron Dosimetry

    International Nuclear Information System (INIS)

    Vanhavere, F.

    2001-01-01

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

  6. Neutron Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Vanhavere, F

    2001-04-01

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

  7. Recent advances in neutron tomography

    International Nuclear Information System (INIS)

    McFarland, E.; Massachusetts Inst. of Technology, Cambridge, MA; Lanza, R.

    1993-01-01

    Neutron imaging has been shown to be an excellent imaging tool for many nondestructive evaluation applications. Significantly improved contrast over X-ray images is possible for materials commonly found in engineering assemblies. The major limitations have been the neutron source and detection. A low cost, position sensitive neutron tomography detector system has been designed and built based on an electro-optical detector system using a LiF-ZnS scintillator screen and a cooled charge coupled device. This detector system can be used for neutron radiography as well as two and three-dimensional neutron tomography. Calculated performance of the system predicted near-quantum efficiency for position sensitive neutron detection. Experimental data was recently taken using this system at McClellan Air Force Base, Air Logistics Center, Sacramento, CA. With increased availability of low cost neutron sources and advanced image processing, neutron tomography will become an increasingly important nondestructive imaging method

  8. The secondary neutron sources for generation of particular neutron fluxes

    International Nuclear Information System (INIS)

    Tracz, G.

    2007-07-01

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

  9. Inhomogeneity of neutron and gamma-ray attenuation in biological shields

    Energy Technology Data Exchange (ETDEWEB)

    El-bakkoush, F A; El-Ghobary, A M; Megahid, R M [Reactor and Neutron physics Department, Nuclear Research Center, A.E.A., Cairo (Egypt)

    1997-12-31

    Measurements have been carried-out to investigate the attenuation properties of some materials which are used as biological shields around nuclear radiation sources. Investigation was performed by measuring the transmitted fast neutron and gamma-spectra through cylindrical samples of magnetite- limonite, steel and cellulose shields. The neutron and gamma spectra were measured by a neutron-gamma spectrometer with stilbene scintillator. Discrimination between neutron and gamma pulses was achieved by a discrimination method. The obtained results are displayed in the form of neutron and gamma spectra and attenuation relations which are used to derive the total macroscopic cross-sections for neutrons and total linear attenuation coefficients for gamma-rays. The values of neutron and gamma relaxation lengths are also derived for the investigated materials. 10 figs., 1 tabs.

  10. Nuclear characteristics of epoxy resin as a space environment neutron shielding

    Energy Technology Data Exchange (ETDEWEB)

    Adeli, Ruhollah [Nuclear Science and Technology Research Institute, Yazd (Iran, Islamic Republic of). Central Iran Research Complex; Shirmardi, Seyed Pezhman [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). Radiation Application Research School; Mazinani, Saideh [Amirkabir Nanotechnology Research Institute, Tehran (Iran, Islamic Republic of); Ahmadi, Seyed Javad [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). Nuclear Fuel Cycle Research School

    2017-03-15

    In recent years many investigations have been done for choosing applicable light neutron shielding in space environmental applications. In this study, we have considered the neutron radiation-protective characteristics of neat epoxy resin, a thermoplastic polymer material and have compared it with various candidate materials in neutron radiation protection such as Al 6061 alloy and Polyethylene. The aim of this investigation is the effect of type of moderator for fast neutron, notwithstanding neutron absorbers fillers. The nuclear interactions and the effective dose at shields have been studied with the Monte Carlo N-Particle transport code (MCNP), using variance reductions to reduce the relative error. Among the candidates, polymer matrix showed a better performance in attenuating fast neutrons and caused a lower neutron and secondary photon effective dose.

  11. EURISOL-DS multi-MW target unit: Neutronics performance and shielding assessment, dose rate and material activation calculations for the MAFF configuration

    CERN Document Server

    Romanets, Y; Kadi, Y; Luis, R; Goncalves, I F; Tecchio, L; Kharoua, C; Vaz, P; Ene, D; David, J C; Rocca, R; Negoita, F

    2010-01-01

    One of the objectives of the EURISOL (EURopean Isotope Separation On-Line Radioactive Ion Beam) Design Study consisted of providing a safe and reliable facility layout and design for the following operational parameters and characteristics: (a) a 4 MW proton beam of 1 GeV energy impinging on a mercury target (the converter); (b) high neutron fluxes (similar to 3 x 10(16) neutrons/s) generated by spallation reactions of the protons impinging in the converter and (c) fission rate on fissile U-235 targets in excess of 10(15) fissions/s. In this work, the state-of-the-art Monte Carlo codes MCNPX (Pelowitz, 2005) and FLUKA (Vlachoudis, 2009; Ferrari et al., 2008) were used to characterize the neutronics performance and to perform the shielding assessment (Herrera-Martinez and Kadi, 2006; Cornell, 2003) of the EURISOLTarget Unit and to provide estimations of dose rate and activation of different components, in view of the radiation safety assessment of the facility. Dosimetry and activation calculations were perfor...

  12. Testing measurements at horizontal channels of the MARIA reactor performed using neutron spectrometers; Pomiary testowe przy kanalach poziomych reaktora MARIA wykonane przy uzyciu spektrometrow neutronow

    Energy Technology Data Exchange (ETDEWEB)

    Murasik, A. [Institute of Atomic Energy, Otwock-Swierk (Poland)

    1997-12-31

    By means of neutron diffraction, using the standard polycrystalline sample of Al{sub 2}O{sub 3}, measurements on three (of four spectrometers) already installed in the front of horizontal channels of MARIA reactor have been performed. Basing on these experiments as well as on activation measurements carried out earlier, the fluxes of monoenergetic neutrons have been estimated. These experiments allowed to determine (for a given geometry and kind of monochromators chosen) the resolution efficiency of instruments and high order contamination in the reflected beam. With the help of polycrystalline vanadium and TbBr{sub 3} sample, the possibility of studies using the inelastic scattering process have been tested. (author) 7 refs, 15 figs, 7 tabs

  13. Coupled moderator neutronics

    International Nuclear Information System (INIS)

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

    1995-01-01

    Optimizing the neutronic performance of a coupled-moderator system for a Long-Pulse Spallation Source is a new and challenging area for the spallation target-system designer. For optimal performance of a neutron source, it is essential to have good communication with instrument scientists to obtain proper design criteria and continued interaction with mechanical, thermal-hydraulic, and materials engineers to attain a practical design. A good comprehension of the basics of coupled-moderator neutronics will aid in the proper design of a target system for a Long-Pulse Spallation Source

  14. Relative evaluation of neutron activation, X-ray fluorescence and spark source mass spectrometry for multielement analysis of geothermal waters

    International Nuclear Information System (INIS)

    Blommaert, W.; Vandelannoote, R.; Van't Dack, L.; Gijbels, R.; Van Grieken, R.

    1980-01-01

    To sulfide geothermal waters from the French Pyrenees region and bicarbonate and chloride waters from the French Vosges area, all of the following analysis techniques were applied in order to compose a broad inventory of trace elements: (1) for the dissolved metarial: neutron activation analysis after a freeze-drying step using a very short cycle, short cycle or long cycle, neutron activation after co-crystallization on 1-(2-pyridylazo)-2-naphthol (PAN) using a short cycle or long cycle, X-ray fluorescence after co-crystallization on PAN and spark source mass spectrometry after evaporation on graphite or preconcentration on PAN, and, (2) for the filtered or suspended material: neutron activation using a very short, short or long cycle and X-ray fluorescence. Altogether, on the average some 30 elements could be determined above the detection limit in solution and 15 in suspension. (author)

  15. Diagnosis-Related Groups (DRG and Hospital Business Performance Management

    Directory of Open Access Journals (Sweden)

    Szynkiewicz Piotr

    2014-12-01

    Full Text Available The goal of this article is to present the possibility of using Diagnosis- Related Groups (DRG in the hospital management process and to analyse the need for business performance management on the part of hospital management staff. The following research methods were used: literature analysis, case studies, and poll analysis. It is not possible to increase the effectiveness of operation of healthcare entities without increasing the importance of IT systems and using DRG more effectively in the management process. Training users in IT and the use of DRGs is important to achieving hospital effectiveness. The increased importance of analyses and planning in a hospital should be reflected in the organisational structure of service providers. Hospital controllers should have a similar role to those present in most companies in other industries.

  16. Performance of a three-axes crystal spectrometer at IEA-Sao Paulo, Brazil: measurements of dispersion relations in copper

    International Nuclear Information System (INIS)

    Fuhrmann, C.; Fulfaro, R.; Vinhas, L.A.

    1978-01-01

    With the purpose to check the performance of IEA Triple Axis Spectrometer of which construction was recently finished, dispersion relation curves for copper at room temperature have been messured. The frequencies of phonons propagating along the three major simmetry directions [xi00] [xixi0] and [xixixi] have been determined. The measurements were carried out operating the Triple Axis Spectrometer in the 'Q constant' mode at neutron energy loss. An excellent agreement could be observed between the results obtained in the present experiment and the accurate data for copper presented in the litterature. In such way, we can conclude that the IEA Triple Axis Spectrometer is in good operational conditions and able to perform original experiments. In this report an outline of the theory of the spectrometer operation and details on the experimental procedures for the case of a Triple Axis Spectrometer operating in the 'Q constant' mode are also presented [pt

  17. The shielding performance of multilayer composite shielding structures to 14.8 MeV fast neutrons

    International Nuclear Information System (INIS)

    Shen Zhiqiang; Kang Qing; Xu Jun; Wang Zhenggang; Lu Nan

    2014-01-01

    Cement-based round thin-layer samples mixed with 30% quality content of barite, and 20% quality content of carbide boron has Prepared, the same-diameter sliced samples of pure graphite and pure polyethylene has cut, then, samples combination and cross stack order has designed, formed four species Multilayer Composite shield structure, at last, neutron attenuation measurements has been done by experimental system of using 14.8 MeV neutrons from the 5SDH-2 accelerator and long counter composition, penetrating rate of samples and the shield structure to 14.8 MeV fast neutron has tested, and attenuation section has calculated. Results show that 14.8 MeV fast neutrons to higher penetration rates of thin layer samples, attenuation cross section of samples distinguish small between each other, must be increasing the thickness of the samples to reduce the experimental uncertainty; through composed of attenuation cross section and thickness parameters of composite structure, can more accurately predict the shielding ability of composite structures, error between calculation results and experimental results in 4%. (authors)

  18. Shielding performances analysis for the IFMIF test facility based on high-fidelity Monte Carlo neutronic calculations

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, Keitaro, E-mail: kondo.keitaro@jaea.go.jp; Arbeiter, Frederik; Fischer, Ulrich; Lu, Lei; Qiu, Yuefeng; Tian, Kuo

    2015-10-15

    Highlights: • A detailed geometry model with pipe penetrations and gaps was prepared for the IFMIF test cell. • The neutron streaming effect due to gaps and pipes with shielding plugs was investigated. • The present analysis revealed that the streaming effect can be mitigated by some counter measures. • Occupational workers can access to the room above the test cell during operation. - Abstract: The IFMIF Test Cell (TC) design was developed and optimized in the EVEDA phase, and finally the reference TC design was proposed. The present study is devoted to further investigations of open issues on the reference TC design. In order to examine the neutron streaming effect caused by pipe penetrations and gaps around removable shielding plugs, a new geometry model for neutronic analyses has been prepared directly from engineering CAD data by utilizing the McCad conversion software. All removable shielding plugs are separately described in the model and a detailed description of pipes was incorporated into the model. The calculation result suggests that the streaming effect is mitigated if the pipe penetration is designed appropriately, while the gaps around the shielding plugs above the TC have large impact on the radiation dose in the access cell. The concept of the reference TC design has been basically validated from the neutronics point of view, although the streaming effect should be compensated by the shielding capability of the test cell cover plate so that occupational workers can access to the access cell during operation.

  19. Shielding performances analysis for the IFMIF test facility based on high-fidelity Monte Carlo neutronic calculations

    International Nuclear Information System (INIS)

    Kondo, Keitaro; Arbeiter, Frederik; Fischer, Ulrich; Lu, Lei; Qiu, Yuefeng; Tian, Kuo

    2015-01-01

    Highlights: • A detailed geometry model with pipe penetrations and gaps was prepared for the IFMIF test cell. • The neutron streaming effect due to gaps and pipes with shielding plugs was investigated. • The present analysis revealed that the streaming effect can be mitigated by some counter measures. • Occupational workers can access to the room above the test cell during operation. - Abstract: The IFMIF Test Cell (TC) design was developed and optimized in the EVEDA phase, and finally the reference TC design was proposed. The present study is devoted to further investigations of open issues on the reference TC design. In order to examine the neutron streaming effect caused by pipe penetrations and gaps around removable shielding plugs, a new geometry model for neutronic analyses has been prepared directly from engineering CAD data by utilizing the McCad conversion software. All removable shielding plugs are separately described in the model and a detailed description of pipes was incorporated into the model. The calculation result suggests that the streaming effect is mitigated if the pipe penetration is designed appropriately, while the gaps around the shielding plugs above the TC have large impact on the radiation dose in the access cell. The concept of the reference TC design has been basically validated from the neutronics point of view, although the streaming effect should be compensated by the shielding capability of the test cell cover plate so that occupational workers can access to the access cell during operation.

  20. Do candidate reactions relate to job performance or affect criterion-related validity? A multistudy investigation of relations among reactions, selection test scores, and job performance.

    Science.gov (United States)

    McCarthy, Julie M; Van Iddekinge, Chad H; Lievens, Filip; Kung, Mei-Chuan; Sinar, Evan F; Campion, Michael A

    2013-09-01

    Considerable evidence suggests that how candidates react to selection procedures can affect their test performance and their attitudes toward the hiring organization (e.g., recommending the firm to others). However, very few studies of candidate reactions have examined one of the outcomes organizations care most about: job performance. We attempt to address this gap by developing and testing a conceptual framework that delineates whether and how candidate reactions might influence job performance. We accomplish this objective using data from 4 studies (total N = 6,480), 6 selection procedures (personality tests, job knowledge tests, cognitive ability tests, work samples, situational judgment tests, and a selection inventory), 5 key candidate reactions (anxiety, motivation, belief in tests, self-efficacy, and procedural justice), 2 contexts (industry and education), 3 continents (North America, South America, and Europe), 2 study designs (predictive and concurrent), and 4 occupational areas (medical, sales, customer service, and technological). Consistent with previous research, candidate reactions were related to test scores, and test scores were related to job performance. Further, there was some evidence that reactions affected performance indirectly through their influence on test scores. Finally, in no cases did candidate reactions affect the prediction of job performance by increasing or decreasing the criterion-related validity of test scores. Implications of these findings and avenues for future research are discussed. PsycINFO Database Record (c) 2013 APA, all rights reserved