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A bicrystal monochromator of moderate wavelength resolution for use with X‐rays or thermal neutrons
Author(s) -
Bauspiess W.,
Bonse U.,
Graeff W.,
Rauch H.
Publication year - 1977
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/s0021889877013570
Subject(s) - monochromator , optics , misorientation , wavelength , bragg's law , germanium , neutron , materials science , silicon , radiation , resolution (logic) , physics , diffraction , optoelectronics , microstructure , quantum mechanics , artificial intelligence , computer science , grain boundary , metallurgy
A new type of crystal monochromator is presented which facilitates the selection of a precisely fixed wavelength λ 0 from a continuum at an intermediate bandwidth Δλ/λ of typically 10 −3 . Its essential feature is consecutive Bragg reflections from two crystals with slightly different Bragg‐plane spacings glued rigidly together at near‐parallel orientation. The bicrystal effectively manifests a wavelength standard the exact value of which is determined by the angle β of misorientation of the two crystals. The application of a germanium–silicon version of the new device to neutron interferometry is described. The influence of ray geometry on the values of λ 0 and Δλ is discussed.