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Neutron diffraction studies of a double‐crystal (+ n ,– m ) setting containing a fully asymmetric diffraction geometry of a bent perfect crystal with output beam expansion
Author(s) -
Mikula Pavol,
Vrána Miroslav,
Pilch Jan,
Seok Seong Baek,
Woo Wanchuck,
Em Vyacheslav
Publication year - 2014
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/s1600576714001964
Subject(s) - bent molecular geometry , diffraction , crystal (programming language) , geometry , neutron diffraction , beam (structure) , diffraction topography , optics , materials science , crystallography , physics , x ray crystallography , chemistry , mathematics , computer science , composite material , programming language
The neutron diffraction properties of a double‐crystal (+ n ,− m ) setting, which contains a bent perfect Si(311) crystal in the fully asymmetric diffraction (FAD) geometry with output beam expansion and a bent perfect Si(220) crystal in the symmetric diffraction geometry, are presented. Generally, there are two possibilities for the FAD geometry: either with output beam compression or with output beam expansion. In this case, attention has been focused on the latter. The properties of the (+ n ,− m ) double‐bent‐crystal arrangement of a bent perfect crystal FAD Si(311) geometry, in combination with a bent Si(220) crystal slab in the symmetric diffraction geometry, were studied. It was found that, after beam expansion, this FAD geometry can provide a monochromatic beam of rather large cross section but very small divergence.