Hostname: page-component-78c5997874-8bhkd Total loading time: 0 Render date: 2024-11-19T04:11:36.035Z Has data issue: false hasContentIssue false
  • English
  • Français

A Method for Trace Analysis with an Electron Microprobe

Published online by Cambridge University Press:  06 March 2019

L. A. Fergason
L. A. Fergason*
Affiliation:
Mallinckrodt Chemical Works, Saint Charles, Missouri
Get access

Abstract

A “chopped beam” system of analysis has been devised for a scanning electron microprobe equipped with a 400-channel analyzer. The system has been programed with circuitry which places a signal onto the X or Y scanning coils of the probe, so that the beam jumps back and forth between two analytical areas. The same signal is used to activate alternate halves or quadrants on the 400-channel analyzer in a synchronous manner. The analyzer accumulates X-ray intensity data in the appropriate halves and quadrants as the electron beam oscillates between sample and standard or, in the case of trace analysis, between the unknown and the pure major constituent for background correction. The probe may be left unattended while it is gathering information in this manner. The dwell time of the probe on a given analytical area is 6 sec “live” time.

Errors due to instrumental drift and sample contamination are nullified or minimized by this technique. Consequently, theoretical precision is closely approached for extended counting times. 100 ppm levels of aluminum, silicon, nickel, and iron in uranium have been determined to precisions as good as ± 10 ppm at the 95% confidence level.

Type
Research Article
Information
Advances in X-Ray Analysis , Volume 9: Fourteenth Annual Conference on Applications of X-ray Analysis, August 25-27, 1965 , 1965 , pp. 265 - 272
Copyright
Copyright © International Centre for Diffraction Data 1965

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. Theisen, R., “Detection Limits of Electron Microprobe Analysis,” presented at E.C.S.-A.I.M.E. Meeting, Toronto, May 1964.Google Scholar
2. Ziebold, T. O., “Trace Determinations in Microanalysis, “ presented as a lecture at M.I.T. Special Summer Program on the Electron Microanalyzer and its Application, August 3-4, 1964.Google Scholar
3. Birks, L. S., Electron Probe Microanalysis, Interscience Publishers, Inc., New York, 1963, p. 136.Google Scholar
4. Jarret, A., Statistical Methods Used in the Measurement of Radioactivity, Technical Information Service Extension, U.S. Atomic Energy Commission, AECU-262, June 1946.Google Scholar
5. Fergason, L. A. and Neumann, N. F., “An Energy Dispersion System for Light Element Analysis with the Microprobe,” to be published.Google Scholar
6. Ziebold, T. O. and Ogilvie, R. E., “Quantitative Analysis with the Electron. Microanalyzer,” Anal. Chem. 35: 621, 1963.Google Scholar