Hostname: page-component-cd9895bd7-gxg78 Total loading time: 0 Render date: 2024-12-25T02:38:29.892Z Has data issue: false hasContentIssue false
  • English
  • Français

Precision Lattice Parameter Measurements with Guinier Camera and Counter Diffractometer: Comparison and Reconciliation of Results

Published online by Cambridge University Press:  06 March 2019

Allan Brown
Allan Brown*
Affiliation:
Studsvik Energiteknik AB, S-611 82 Nyköping, Sweden
Get access

Extract

Different procedures used in precision measurements of lattice parameters are, strictly, only valid if they can be shown to give results that are mutually reproducible. For this purpose reproducibility is defined in terms of the parameters a. and standard deviations a. obtained for X-ray specimens of one or more reference materials. The requirement is that all systematic errors should be minimized to a level below that of the random measurement errors. Where these have a Gaussian distribution the significance of the difference, Δa°, between two , measurements can then be Let;Led by evaluating . Thus, if K < 2 the difference, Δa°, cannot be distinguished from the effects of random measurement errors. This condition should be met for specimens of the same sample if reproducibility is good. For K ≥ 3 the value of Δa° is then taken to reflect real differences in the crystalline Jattice of two X-ray specimens of a given compound. A basis is thus created for the study of solid solubility and for the precise characterization of crystalline compounds.

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. 11 - 24
Copyright
Copyright © International Centre for Diffraction Data 1982

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Brown, A., Edmonds, J. W. and Foris, C. M., “Reproducibility and Precision of Guinier Patterns Using Powdered Silicon Calibrant”, Adv. X-ray Anal. 24 111 (Edited by Smith, Deane K., Plenum Press, 1981).Google Scholar
2. Brown, A. and Foris, C. M., “Precision and Reproducibility of Eactice Parameters from Gttinier Powder Patterns:Followup and Assessment”. (For publication in Adv. X-ray Anal. 1983).Google Scholar
3. Hubbard, C. R., Swansoii, H. E. and Mauer, F. A., “A Silicon Powder Diffraction Standard Reference Material”, J. Appl, Crystallogr. 8 45 (1975).Google Scholar
4. Parrish, W. and Wilson, A. J. C., “Precision Measurements of Lattice Parameters of Polycrystalline Specimens”, Int. Tables X-ray Cryst., Vol. II, 216 (Edited by Kasper, J. S. and Kathleen Lonsdale, Kynoch Press, 1959).Google Scholar
5. Mueller, M. H. and Heaton, L., “Determination of Lattice Parameters with the Aid of a Computer”, AEC Research and Development Report, ANL 6176 (1961).Google Scholar
6. Beu, K. E. and Whitney, D. R., “Further Developments in the Likelihood Ratio Method for the Precise and Accurate Determination of Lattice Parameters”, AEC Research and Development Report, GAT-T-1289/Rev 1 (1965).Google Scholar
7. Smith, G. S. and Snyder, R. L., A Criterion for Rating Powder Diffraction Patterns and Evaluating the Reliability of Powder-Pattern Indexing”, J. Appl. Cryst. 12 60 (1979).Google Scholar
8. Jenkins, R. and Paolini, F. R., “An Automatic Divergence Slit for the Powder Diffractometer”, Norelco Reporter 21“ 9. (1974).Google Scholar
9. Bystrom-Asklund, A. M., “Sample Cups and a Technique for Sideward Packing of X-ray Diffractometer Specimens”, Am. Mineral 51 1233 (1966).Google Scholar
10. Hess, J. B., “A Modification of the Cohen Procedure for Computing Precision Lattice Constants from Powder Data”, Acta Cryst. 4 209 (1951).Google Scholar
11. Discussions with Beard, D. W., Siemens Corporation and J. Pich.ert, Aniperex Electronic Corp.Google Scholar
12. Edmonds, J. W., “Precision Guinier X-ray Powder Diffraction Data”, National Bureau of Standards Special Publication 567. Proceedings of Symposium on Accuracy in Powder Diffraction, Gaithersburg, MD, 1979 (Edited by Block, S. and Hubbard, C-R., NBS, 1980).Google Scholar