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Accuracy and Precision of Intensities in X-Ray Polycrystalline Diffraction

Published online by Cambridge University Press:  06 March 2019

W. Parrish  and
T. C. Huang
W. Parrish
Affiliation:
IBM Research Laboratory, 5600 Cottle Road, San Jose, California 95193
T. C. Huang
Affiliation:
IBM Research Laboratory, 5600 Cottle Road, San Jose, California 95193
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Abstract

The integrated and peak intensities of a series of silicon powder samples of various crystallite sizes were measured with a computer automated diffractometer and a profile fitting method (PFM). The accuracy of the PFM was better than 0.003% in computing the integrated intensities. The PFM gave more precise values than would be expected from counting statistics of the peak intensity. The average difference between each measurement and the average intensity was 0.5% with little dependence oo the absolute intensity. Crystallite sizes have a large effect and it is essential to rotate the specimen around the diffraction vector. The best results were obtained with <10 μm particles. Larger sizes decrease the absolute intensities and change the relative intensities. Structure refinement using the POWLS (powder least squares refinement) program showed the presence of (111) preferred orientation even in the <10 μm specimens. R(Bragg) decreased from 4.3% to 0.7% by including the preferred orientation correction in the refinement.

Type
I. Accuracy in X-Ray Powder Diffraction
Information
Advances in X-Ray Analysis , Volume 26: Thirty-First Annual Conference on Applications of X-ray Analysis, August 1-6, 1982 , 1982 , pp. 35 - 44
Copyright
Copyright © International Centre for Diffraction Data 1982

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References

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