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Characterisation and Modelling of Peak Shifts in Conventional Powder Diffractometry

Published online by Cambridge University Press:  06 March 2019

Robert W. Cheary ,
James P. Cline  and
Maree Anast
Robert W. Cheary
Affiliation:
Department of Applied Physics, University of Technology, Sydney, P.O. Box 123, Broadway, NSW, Australia 2007
James P. Cline
Affiliation:
Ceramics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899 USA
Maree Anast
Affiliation:
Department of Applied Physics, University of Technology, Sydney, P.O. Box 123, Broadway, NSW, Australia 2007
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Abstract

The peak angle 2θp is one of the most commonly measured parameters in powder diffractometry, but there is little understanding of the extent to which the instrument affects this measurement. The majority of theoretical and experimental studies of the effects of instrumental aberrations have been based on the peak centroid 29c. In this investigation we have examined the extent to which peak angles in a conventional powder diffractometer shift for different combinations of divergence slit, Soller slits and receiving slit. The line profile standard SRM 660 (LaB6) was used to generate instrument profiles and X-ray data were collected from a diffractometer fitted with a fine focus Cu X-ray tube and a graphite post-monochromator set for CuKa. The effect of the instrument is greatest at low angles, but shifts arising from axial divergence can also be detected above 2θ=120°. Below 2θ = 40° changing the divergence slits from 0.3° to 1.0°, or removing one of the Soller slits, can move 2θp by up to 0.025°.

Type
Research Article
Information
Advances in X-Ray Analysis , Volume 39: Forty-Fourth Annual Conference on Applications of X-ray Analysis, July 31 - August 4, 1995 , 1995 , pp. 579 - 587
Copyright
Copyright © International Centre for Diffraction Data 1995

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References

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