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The Geometric Origin of Asymmetric Small Angle Neutron Scattering from an Elastically Bent Double Crystal Diffractometer
Author(s) -
McMahon P. J.,
Treimer W.
Publication year - 1998
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/(sici)1521-4079(1998)33:4<625::aid-crat625>3.0.co;2-y
Subject(s) - diffractometer , bent molecular geometry , crystal (programming language) , analyser , monochromator , small angle neutron scattering , materials science , crystallography , neutron , scattering , neutron scattering , molecular physics , optics , crystal structure , chemistry , physics , nuclear physics , wavelength , computer science , programming language , composite material
We have investigated the Small Angle Neutron Scattering (SANS) from a Double Crystal Diffractometer (DCD) in the (1, —1) setting using a focusing Si monochromator crystal in the symmetric (111) case and a defocusing analyser Si crystal in a completely asymmetric (111) case. We have found that SANS data from porous glassy carbon and Silica spheres are asymmetric about the Bragg Peak centre. We attribute this observation to a combination of factors, particularly geometrical effects, related to the angle of acceptance χ into the analyser crystal when a SANS sample is positioned between the crystal pair. A simple procedure for SANS data correction is outlined and shown to be effective in this case.