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An elastically bent silicon crystal as a monochromator for thermal neutrons
Author(s) -
Mikula P.,
Krüger E.,
Scherm R.,
Wagner V.
Publication year - 1990
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/s0021889889012975
Subject(s) - monochromator , bent molecular geometry , optics , diffraction , crystal (programming language) , monocrystalline silicon , beam (structure) , neutron , monochromatic color , silicon , materials science , radius , diffractometer , neutron diffraction , physics , optoelectronics , nuclear physics , wavelength , composite material , programming language , computer security , computer science , scanning electron microscope
Some experimental results are presented for an elastically bent perfect silicon crystal in a strongly asymmetric diffraction geometry as a neutron monochromator. The use of this unconventional geometry of the monochromator appears to be suitable for a wide (several centimetres) incident polychromatic beam, when, thanks to the spatial condensation of the diffracted neutrons (Fankuchen effect), a high monochromatic beam density may be obtained. Furthermore, when using focusing in real and in momentum space by adjusting an optimum bending radius, the intensity diffracted by a sample may be comparable even with the best mosaic monochromators such as highly oriented pyrolytic graphite (PG). A comparison is demonstrated on the rocking curves of a strongly mosaic Ni–Al(020) crystal obtained with the monochromatic beam from bent Si(111), Si(400) and from PG(002), Cu(220) mosaic monochromators.