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A New Model For Electron Probe Quantification

Published online by Cambridge University Press:  02 July 2020

John J. Donovan
Affiliation:
Department of Geology and Geophysics, The University of California, Berkeley, California94720-4767
Nicholas E. Pingitore Jr.
Affiliation:
Department of Geological Sciences, The University of Texas at El Paso, El Paso, Texas79968-0555
Raymond Jeanloz
Affiliation:
Department of Geology and Geophysics, The University of California, Berkeley, California94720-4767
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Extract

Castaing’s first approximation assumes that the characteristic radiation emitted by each element in a compound is unaffected by the presence of the other elements, and that the intensity of the radiation emitted by each element in the compound is proportional to its mass concentration. From Castaing’s first approximation based on mass fractions, the initial estimate of the concentration of an element in a compound is

where C and are mass fractions in the sample and standard, and I and are x-ray emission intensities of a specific transition measured in the sample and the standard. Surprisingly, the mass fraction approach works well in practice, even though it lacks any obvious physical basis. This can be understood by considering that for typical energies involved in EPMA (50 keV or less), the size of the nucleus is several orders of magnitude smaller than the average incident beam electron wavelength.

Type
Quantitative X-Ray Microanalysis
Copyright
Copyright © Microscopy Society of America

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References

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