High Precision Multiple keV X-Ray Analysis: Part I. Tests of K-Shell Ionization Cross

Published

October 16, 2008

Author(s)

J T. Armstrong, Dale E. Newbury, Paul Carpenter

Abstract

To evaluate which models of x-ray emission and ionization cross section give the most accurate results when applied to quantitative x-ray emission measurements, we performed a series of high precision measurements of K-shell x-ray intensities as a function of electron beam accelerating potential. These measurements were made using K-lines of elements ranging in atomic number from C to Se from a series of pure element standards and simple compounds. Replicate measurements were made at electron beam accelerating potentials of (5, 10, 15, 20, 25, and 30) keV using both wavelength and energy dispersive spectrometers. Typical measurement precisions were better than 0.3 % relative (1 ς). The measured emitted x-ray intensities were corrected for absorption and electron backscatter using the average of six of the commonly used correction algorithms. The results were compared to relative intensities calculated by various relative x-ray production expressions (used in the characteristic fluorescence correction), and by numerical integration of the ratio of the various ionization cross section expressions to the average of twelve expressions for the electron stopping power (used in the atomic number correction). None of the commonly used expressions for relative x-ray intensity in the characteristic fluorescence correction was in good agreement with the experimental measurements. Many of the commonly used expressions for the ionization cross section (when integrated with an average value of the stopping power expression) produce only poor or fair agreement with the experimental data. However, three of the ionization cross section expressions, those of Casnati et al. (1982), Pouchou and Pichoir (1991), and Pouchou (1994), produce excellent agreement with entire K-line measurement data set.

Citation

Scanning, The Journal of Scanning Microscopies

Pub Type

Journals

Keywords

accelerating potential, atomic number corrections, electron interactions, electron probe microanalysis

Citation

Armstrong, J. , Newbury, D. and Carpenter, P. (2008), High Precision Multiple keV X-Ray Analysis: Part I. Tests of K-Shell Ionization Cross, Scanning, The Journal of Scanning Microscopies (Accessed December 12, 2024)