Hostname: page-component-848d4c4894-4rdrl Total loading time: 0 Render date: 2024-06-26T20:46:32.268Z Has data issue: false hasContentIssue false
  • English
  • Français

A Search/Match Procedure for Electron Diffraction Data Based on Pattern Matching in Binary Bit Maps*

Published online by Cambridge University Press:  10 January 2013

Martin J. Carr ,
William F. Chambers  and
David Melgaard
Martin J. Carr
Affiliation:
Sandia, National Laboratories, Albuquerque, New Mexico 87185, U.S.A.
William F. Chambers
Affiliation:
Sandia, National Laboratories, Albuquerque, New Mexico 87185, U.S.A.
David Melgaard
Affiliation:
J&M Systems, Ltd., Albuquerque, New Mexico 87185, U.S.A.
Get access Rights & Permissions [Opens in a new window]

Abstract

A unique file structure and search algorithm have been developed for the purpose of obtaining matches between experimental electron diffraction and qualitative energy dispersive X-ray compositional data from an unknown crystalline phase and the reference data in the JCPDS Powder Diffraction File. The reference data for over 32,000 inorganic compounds from sets 1–33 were compressed and stored in binary format as bit pattern maps. The entire data set and searching programs require less than 4 Mbyte and retain the precision appropriate for electron diffraction analysis. The search algorithm, written in both RT-11 FORTRAN and Flextran, is based on pattern matching between bit maps obtained for the unknown and reference compounds for both composition and diffraction data. Special attention is given to double diffraction effects commonly encountered in electron diffraction analysis. The programs run on an interactive basis on a microcomputer dedicated to the X-ray energy dispersive spectrometer on an analytical electron microscope. A typical search takes about 15 seconds to run and extracts about 10–15 different compounds.

Type
Research Article
Information
Powder Diffraction , Volume 1 , Issue 3 , September 1986 , pp. 226 - 234
Copyright
Copyright © Cambridge University Press 1986

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.Nichols, M. C. and Johnson, Q., “The Search-Match Problem”, Advances in X-ray Analysis 23, Plenum Press, New York (1979), p.273.Google Scholar
2.Joint Committee on Powder Diffraction Standards, JCPDS International Centre for Diffraction Data, 1601 Park Lane, Swarthmore, PA 19081.Google Scholar
3.Hanawalt, J. D., “Phase Identification by X-Ray Powder Diffraction”, Advances in X-ray Analysis 20, Plenum Press, New York (1977), p.63.CrossRefGoogle Scholar
4.Goehner, R. P. and Garbauskas, M. F., “PDIDENT – A Set of Programs for Powder Diffraction Phase Identification”, X-Ray Spectrometry 13, no. 4 (1984), p. 172.CrossRefGoogle Scholar
5.Anderson, R. and Johnson, G. G. Jr., “The MAX-d Alphabetical Index to the JCPDS Data Base: A New Tool for Electron Diffraction Analysis”, in: 37th Annual Proceedings of the Electron Microscopy Society of American, San Antonio, Texas, ed. by Bailey, G. W., p.444 (1979).Google Scholar
6.Carr, M. J. and Chambers, W. F., “RAD: A Comprehensive Software System For Analytical Electron Microscopy”, in: 40th Annual Proceedings of the Electron Microscopy Society of America, Washington, D.C., ed. by Bailey, G. W., p.744 (1982).Google Scholar
7.Carr, M. J. and Chambers, W. F., “A Review of the Crystallographic Calculations Methods Used in the RAD Group of Computer Programs for Analytical Electron Microscopy”, J. of Microscopy 134, pt.1, p.55 (1984).CrossRefGoogle Scholar
8.Edington, J. W., “Practical Electron Microscopy in Materials Science”, Van Nostrand Reinhold Company (1976).Google Scholar
9.Rhoades, B. L., “Indexing of Electron Diffraction Spot Patterns by Computed”, Micron 6, p. 123 (1975).Google Scholar
10.Pearson, W. B., A Handbook of Lattice Spacings and Structures of Metals and Alloys, Pergamon Press (1967).Google Scholar
11.Wyckoff, R. W. G., “Crystal Structures”, Interscience Publishers (1963).Google Scholar
12.Cowley, J. M., Rees, A. L. G., and Spink, J. A., “Secondary Elastic Scattering in Electron Diffraction”, Proc. Phys. Soc. 64, p.609 (1951).CrossRefGoogle Scholar