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Modeling radial collimators for use in stress and texture measurements with neutron diffraction
Author(s) -
Wang D.Q.,
Wang X.L.,
Robertson J. L.,
Hubbard C. R.
Publication year - 2000
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/s0021889800000856
Subject(s) - collimator , neutron , optics , physics , monte carlo method , radius , beam (structure) , neutron diffraction , sampling (signal processing) , diffraction , detector , nuclear physics , mathematics , computer science , statistics , computer security
Radial collimators have been recently introduced to define the sampling volume during neutron diffraction stress and texture mapping experiments. This paper presents both analytical and Monte Carlo numerical models for the calculation of the spatial distribution of neutron transmission through a radial collimator. It is shown that the effective size of the scattered neutron beam as seen by detectors behind the collimator is quite sensitive to the collimator length and the number of blades. For a given radius of a collimator, the effective beam width increases sharply as the length is shortened. Due to the finite blade thickness, the center of gravity of the sampling volume is shifted away from the collimator. In contrast, attenuation of the neutron beam by the sample brings the center of gravity of the sampling volume closer to the collimator.