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Low-Voltage Electron-Probe Microanalysis of Fe–Si Compounds Using Soft X-Rays

Published online by Cambridge University Press:  28 August 2013

Phillip Gopon ,
John Fournelle ,
Peter E. Sobol  and
Xavier Llovet
Phillip Gopon*
Affiliation:
Department of Geoscience, University of Wisconsin, Madison, WI 53706, USA
John Fournelle
Affiliation:
Department of Geoscience, University of Wisconsin, Madison, WI 53706, USA
Peter E. Sobol
Affiliation:
Department of Geoscience, University of Wisconsin, Madison, WI 53706, USA
Xavier Llovet
Affiliation:
CCiTUB, University of Barcelona, ES-08028 Barcelona, Spain
*
*Corresponding author. E-mail: pgopon@geology.wisc.edu
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Abstract

Conventional electron-probe microanalysis has an X-ray analytical spatial resolution on the order of 1–4 μm width/depth. Many of the naturally occurring Fe–Si compounds analyzed in this study are smaller than 1 μm in size, requiring the use of lower accelerating potentials and nonstandard X-ray lines for analysis. Problems with the use of low-energy X-ray lines (soft X-rays) of iron for quantitative analyses are discussed and a review is given of the alternative X-ray lines that may be used for iron at or below 5 keV (i.e., accelerating voltage that allows analysis of areas of interest <1 μm). Problems include increased sensitivity to surface effects for soft X-rays, peak shifts (induced by chemical bonding, differential self-absorption, and/or buildup of carbon contamination), uncertainties in the mass attenuation coefficient for X-ray lines near absorption edges, and issues with spectral resolution and count rates from the available Bragg diffractors. In addition to the results from the traditionally used Fe Lα line, alternative approaches, utilizing Fe Lβ, and Fe Ll-η lines, are discussed.

Keywords

soft X-raylow voltagenanoanalysismicroprobeEPMA
Type
Techniques and Instrumentation Development
Information
Microscopy and Microanalysis , Volume 19 , Issue 6 , December 2013 , pp. 1698 - 1708
Copyright
Copyright © Microscopy Society of America 2013 

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