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Neutron filter efficiency of beryllium and magnesium fluorides
Author(s) -
Al-Qasir Iyad,
Qteish Abdallah
Publication year - 2017
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576717000851
Subject(s) - beryllium , neutron , inelastic neutron scattering , neutron scattering , neutron temperature , inelastic scattering , chemistry , atomic physics , materials science , scattering , analytical chemistry (journal) , nuclear physics , optics , physics , chromatography
The neutron filter efficiency of MgF 2 and BeF 2 has been investigated as a function of neutron incident energy at different temperatures, starting from the phonon density of states (PDOS) calculated using first‐principles techniques, and the results are compared with those of MgO and BeO. Recently, MgF 2 has been suggested as a neutron filter and neutron transmission through it has been experimentally studied. For MgF 2 , excellent agreement between calculated and available experimental data has been achieved for the phonon dispersion relations, constant‐volume specific heat, inelastic scattering cross sections and neutron transmission. The PDOSs of MgF 2 and BeF 2 are found to differ significantly owing to the crystal structure and the cations' mass difference. The inelastic scattering cross sections and filter efficiencies of MgF 2 and BeF 2 show different behaviours, which can be understood to originate from the above PDOS incongruity and the large difference in absorption cross sections of Be and Mg nuclei. BeF 2 is predicted to be a better neutron filter than MgF 2 and MgO, over the temperature range of interest, while it has less ability than BeO to transmit low‐energy neutrons.