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V. P. Smolyar - One of the best experts on this subject based on the ideXlab platform.

  • Neutron Moderation spectrum considering inelastic scattering
    arXiv: Nuclear Theory, 2018
    Co-Authors: Vitalii Danilovich Rusov, V. P. Smolyar, V. V. Urbanevich, V.m. Vashchenko, S.a. Chernezhenko, A.a. Kakaev, V. A. Tarasov
    Abstract:

    For the first time an analytic expression for inelastic Neutron scattering law for isotropic Neutron source considering moderating medium temperature as a parameter was obtained in the present paper within gas model. The obtained scattering law is based on solution of kinematic problem of inelastic scattering of a Neutron at a nucleus in laboratory coordinate system ($L$-system) in general case. I.e. in case not only a Neutron but also a nucleus have arbitrary velocity vector in $L$-system. Analytic expression for Neutron flux density and Neutron Moderation spectrum in reactor fission medium are found for elastic scattering law obtained by the authors before and for new law of inelastic scattering. They consider elastic and inelastic scattering and depend on medium temperature. The obtained expressions for Neutron Moderation spectra enable reinerpretation of physical nature of processes that determine the shape of Neutron spectrum in thermal Neutron energy range.

  • Neutron Moderation theory with thermal motion of the moderator nuclei
    European Physical Journal A, 2017
    Co-Authors: Vitalii Danilovich Rusov, S.a. Chernezhenko, A.a. Kakaev, V. A. Tarasov, V. P. Smolyar
    Abstract:

    In this paper we present the analytical expression for the Neutron scattering law for an isotropic source of Neutrons, obtained within the framework of the gas model with the temperature of the moderating medium as a parameter. The obtained scattering law is based on the solution of the general kinematic problem of elastic scattering of Neutrons on nuclei in the L-system. Both the Neutron and the nucleus possess arbitrary velocities in the L-system. For the new scattering law we obtain the flux densities and Neutron Moderation spectra as functions of temperature for the reactor fissile medium. The expressions for the moderating Neutrons spectra allow reinterpreting the physical nature of the underlying processes in the thermal region.

  • Neutron Moderation Theory Taking into Accout the Thermal Motion of Moderating Medium Nuclei
    The European Physical Journal A, 2017
    Co-Authors: Vitalii Danilovich Rusov, S.a. Chernezhenko, A.a. Kakaev, V. A. Tarasov, V. P. Smolyar
    Abstract:

    In this paper we present the analytical expression for the Neutron scattering law for an isotropic source of Neutrons, obtained within the framework of the gas model with the temperature of the moderating medium as a parameter. The obtained scattering law is based on the solution of the kinematic problem of elastic scattering of Neutrons on nuclei in the L-system in the general case. I.e. both the Neutron and the nucleus possess the arbitrary velocity vectors in the L-system. For the new scattering law the flux densities and Neutron Moderation spectra depending on the temperature are obtained for the reactor fissile medium. The expressions for the moderating Neutrons spectra allow reinterpreting the physical nature of the underlying processes in the thermal region.

Vitalii Danilovich Rusov - One of the best experts on this subject based on the ideXlab platform.

  • Neutron Moderation spectrum considering inelastic scattering
    arXiv: Nuclear Theory, 2018
    Co-Authors: Vitalii Danilovich Rusov, V. P. Smolyar, V. V. Urbanevich, V.m. Vashchenko, S.a. Chernezhenko, A.a. Kakaev, V. A. Tarasov
    Abstract:

    For the first time an analytic expression for inelastic Neutron scattering law for isotropic Neutron source considering moderating medium temperature as a parameter was obtained in the present paper within gas model. The obtained scattering law is based on solution of kinematic problem of inelastic scattering of a Neutron at a nucleus in laboratory coordinate system ($L$-system) in general case. I.e. in case not only a Neutron but also a nucleus have arbitrary velocity vector in $L$-system. Analytic expression for Neutron flux density and Neutron Moderation spectrum in reactor fission medium are found for elastic scattering law obtained by the authors before and for new law of inelastic scattering. They consider elastic and inelastic scattering and depend on medium temperature. The obtained expressions for Neutron Moderation spectra enable reinerpretation of physical nature of processes that determine the shape of Neutron spectrum in thermal Neutron energy range.

  • Neutron Moderation theory with thermal motion of the moderator nuclei
    European Physical Journal A, 2017
    Co-Authors: Vitalii Danilovich Rusov, S.a. Chernezhenko, A.a. Kakaev, V. A. Tarasov, V. P. Smolyar
    Abstract:

    In this paper we present the analytical expression for the Neutron scattering law for an isotropic source of Neutrons, obtained within the framework of the gas model with the temperature of the moderating medium as a parameter. The obtained scattering law is based on the solution of the general kinematic problem of elastic scattering of Neutrons on nuclei in the L-system. Both the Neutron and the nucleus possess arbitrary velocities in the L-system. For the new scattering law we obtain the flux densities and Neutron Moderation spectra as functions of temperature for the reactor fissile medium. The expressions for the moderating Neutrons spectra allow reinterpreting the physical nature of the underlying processes in the thermal region.

  • Neutron Moderation Theory Taking into Accout the Thermal Motion of Moderating Medium Nuclei
    The European Physical Journal A, 2017
    Co-Authors: Vitalii Danilovich Rusov, S.a. Chernezhenko, A.a. Kakaev, V. A. Tarasov, V. P. Smolyar
    Abstract:

    In this paper we present the analytical expression for the Neutron scattering law for an isotropic source of Neutrons, obtained within the framework of the gas model with the temperature of the moderating medium as a parameter. The obtained scattering law is based on the solution of the kinematic problem of elastic scattering of Neutrons on nuclei in the L-system in the general case. I.e. both the Neutron and the nucleus possess the arbitrary velocity vectors in the L-system. For the new scattering law the flux densities and Neutron Moderation spectra depending on the temperature are obtained for the reactor fissile medium. The expressions for the moderating Neutrons spectra allow reinterpreting the physical nature of the underlying processes in the thermal region.

V. Verbinski - One of the best experts on this subject based on the ideXlab platform.

  • A moisture probe using Neutron Moderation for PuO/sub 2/ canister inspection
    IEEE Transactions on Nuclear Science, 1999
    Co-Authors: D. Holslin, L. Foster, V. Verbinski
    Abstract:

    We have been developing a sensor to quickly and non-destructively measure the moisture content of canisters containing PuO/sub 2/. These canisters will be retained in long-term storage facilities and, for stability reasons, must have moisture contents

  • a moisture probe using Neutron Moderation for puo sub 2 canister inspection
    Nuclear Science Symposium and Medical Imaging Conference, 1998
    Co-Authors: D. Holslin, L. Foster, V. Verbinski
    Abstract:

    We have been developing a sensor to quickly and non-destructively measure the moisture content of canisters containing PuO/sub 2/. These canisters will be retained in long-term storage facilities and, for stability reasons, must have moisture contents <0.5 wt%. The technique relies on the Moderation of Neutrons emitted by a radioisotopic source (Cf-252) to determine the hydrogen content of the material. Modeling was used to help optimize the sensor design and to predict the sensitivity to moisture content. A benchmodel was first constructed and tested at SAIC with simulated PuO/sub 2/ using Fe/sub 3/O/sub 4/ and B/sub 4/C; moisture was simulated with nylon rods. The benchmodel was also tested at Los Alamos National Laboratory (LANL) using actual PuO/sub 2/-filled canisters modified to accept polyethylene rods to simulate moisture. The results indicated that the detection limit (one statistical standard deviation) for a 10 minute inspection was less than 1.2 g of water, or 0.04 wt%, in 3 kg of PuO/sub 2/. A prototype system was recently constructed for testing a variety of PuO/sub 2/ samples with various material matrices. Here we present the calculations, sensor designs, tests, test results, and discuss future plans.

  • Moisture probe using Neutron Moderation for PuO{sub 2} canister inspection
    Transactions of the American Nuclear Society, 1997
    Co-Authors: D. Holslin, V. Verbinski, L. Foster
    Abstract:

    At several U.S. Department of Energy sites, where the production of nuclear materials was once active, powdered PuO{sub 2} contained in small metal canisters is sealed in larger containers for long-term storage. To prevent corrosion and the generation of significant amounts of hydrogen gas within the small canisters, the moisture content of the PuO{sub 2} powder must be

  • moisture probe using Neutron Moderation for puo sub 2 canister inspection
    Transactions of the American Nuclear Society, 1997
    Co-Authors: D. Holslin, V. Verbinski, L. Foster
    Abstract:

    At several U.S. Department of Energy sites, where the production of nuclear materials was once active, powdered PuO{sub 2} contained in small metal canisters is sealed in larger containers for long-term storage. To prevent corrosion and the generation of significant amounts of hydrogen gas within the small canisters, the moisture content of the PuO{sub 2} powder must be <0.5 wt%. At present, the canisters are checked using slow and potentially unreliable methods. For reliably, accurately, and quickly measuring the moisture content Of PuO{sub 2} powder in situ, we proposed the development of a system that is based on the Moderation of Neutrons. We discuss the results of calculations and measurements performed in a project supported by Los Alamos National Laboratory (LANL) to examine the capabilities and sensitivity of this inspection technique.

  • A moisture probe based upon Neutron Moderation for in situ use in a cone penetrometer system
    IEEE Transactions on Nuclear Science, 1997
    Co-Authors: D. Holslin, F. Johansen, V. Verbinski, N. Boechler
    Abstract:

    A moisture probe based upon Neutron Moderation has been designed, tested and built for measuring the moisture concentration of hazardous waste stored in the underground waste tanks at the DOE Hanford site. The probe is 1 inch in diameter, 24 inches long, and is deployed using a computer controlled winch into a cone penetrometer for in situ moisture measurements. Two thermal Neutron detectors in a near-far geometry and a low-intensity /sup 252/Cf source are used in the probe to count thermalized Neutrons for determining the moisture content. Several testbeds were constructed and a variety of experiments were performed to determine the optimal detector-source geometry and to rest that the sensor is capable of operating in the expected high temperature and very high gamma-ray fields within the tanks. Several calibration curves of the near-far count rate ratio were determined for tanks contaminated with various levels of Neutron absorbing materials. A field-ready probe and a winch deployment system have been delivered for application of this technology to the Hanford Site tank farms.

J. R. Torgerson - One of the best experts on this subject based on the ideXlab platform.

  • Neutron Moderation in the Oklo natural reactor and the time variation of α
    Physical Review D, 2004
    Co-Authors: Steve K. Lamoreaux, J. R. Torgerson
    Abstract:

    In previous analyses of the Oklo (Gabon) natural reactor to test for a possible time variation of the fine-structure constant $\ensuremath{\alpha},$ a Maxwell-Boltzmann low energy Neutron spectrum was assumed. We present here an analysis where a more realistic spectrum is employed and show that the most recent isotopic analysis of samples implies a decrease in $\ensuremath{\alpha},$ over the last $2\ifmmode\times\else\texttimes\fi{}{10}^{9}$ years since the reactor was operating, of $({\ensuremath{\alpha}}_{\mathrm{past}}\ensuremath{-}{\ensuremath{\alpha}}_{\mathrm{now}})/\ensuremath{\alpha}g~4.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ $(6\ensuremath{\sigma}$ confidence). Issues regarding the interpretation of the shifts of the low energy Neutron absorption resonances are discussed.

S.a. Chernezhenko - One of the best experts on this subject based on the ideXlab platform.

  • Neutron Moderation spectrum considering inelastic scattering
    arXiv: Nuclear Theory, 2018
    Co-Authors: Vitalii Danilovich Rusov, V. P. Smolyar, V. V. Urbanevich, V.m. Vashchenko, S.a. Chernezhenko, A.a. Kakaev, V. A. Tarasov
    Abstract:

    For the first time an analytic expression for inelastic Neutron scattering law for isotropic Neutron source considering moderating medium temperature as a parameter was obtained in the present paper within gas model. The obtained scattering law is based on solution of kinematic problem of inelastic scattering of a Neutron at a nucleus in laboratory coordinate system ($L$-system) in general case. I.e. in case not only a Neutron but also a nucleus have arbitrary velocity vector in $L$-system. Analytic expression for Neutron flux density and Neutron Moderation spectrum in reactor fission medium are found for elastic scattering law obtained by the authors before and for new law of inelastic scattering. They consider elastic and inelastic scattering and depend on medium temperature. The obtained expressions for Neutron Moderation spectra enable reinerpretation of physical nature of processes that determine the shape of Neutron spectrum in thermal Neutron energy range.

  • Neutron Moderation theory with thermal motion of the moderator nuclei
    European Physical Journal A, 2017
    Co-Authors: Vitalii Danilovich Rusov, S.a. Chernezhenko, A.a. Kakaev, V. A. Tarasov, V. P. Smolyar
    Abstract:

    In this paper we present the analytical expression for the Neutron scattering law for an isotropic source of Neutrons, obtained within the framework of the gas model with the temperature of the moderating medium as a parameter. The obtained scattering law is based on the solution of the general kinematic problem of elastic scattering of Neutrons on nuclei in the L-system. Both the Neutron and the nucleus possess arbitrary velocities in the L-system. For the new scattering law we obtain the flux densities and Neutron Moderation spectra as functions of temperature for the reactor fissile medium. The expressions for the moderating Neutrons spectra allow reinterpreting the physical nature of the underlying processes in the thermal region.

  • Neutron Moderation Theory Taking into Accout the Thermal Motion of Moderating Medium Nuclei
    The European Physical Journal A, 2017
    Co-Authors: Vitalii Danilovich Rusov, S.a. Chernezhenko, A.a. Kakaev, V. A. Tarasov, V. P. Smolyar
    Abstract:

    In this paper we present the analytical expression for the Neutron scattering law for an isotropic source of Neutrons, obtained within the framework of the gas model with the temperature of the moderating medium as a parameter. The obtained scattering law is based on the solution of the kinematic problem of elastic scattering of Neutrons on nuclei in the L-system in the general case. I.e. both the Neutron and the nucleus possess the arbitrary velocity vectors in the L-system. For the new scattering law the flux densities and Neutron Moderation spectra depending on the temperature are obtained for the reactor fissile medium. The expressions for the moderating Neutrons spectra allow reinterpreting the physical nature of the underlying processes in the thermal region.