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The energy dependence of the neutron coherent scattering length of europium
Author(s) -
Lynn J. E.
Publication year - 1989
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/s0021889889006400
Subject(s) - europium , scattering , neutron , neutron scattering , nuclide , physics , scattering length , cross section (physics) , range (aeronautics) , atomic physics , nuclear physics , optics , materials science , quantum mechanics , luminescence , composite material
General considerations are given for the importance of providing an energy/wavelength‐dependent database of neutron coherent scattering lengths, and of the possibility of constructing such a base from the range of neutron cross‐section data that are generally available for a wide range of nuclides. The case of europium is considered in detail, partly because it is a good example of an element with strong resonance effects in the wavelength region of importance in crystallographic and condensed‐matter studies, and partly because it is an exceptional case from the nuclear point of view, having multi‐level interference effects. From the available cross‐section data the complex coherent scattering length is constructed as a function of neutron energy up to 0.7 eV, for the isotopes and for the natural element. Some single‐level approximations for the scattering‐length function of 151 Eu are given.