Calculation and comparison of the backscattering factor R for characteristic x‐ray emission

1989

Phys. Stat. Sol. (a)

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Several analytical expressions for the electron backscattering coefficient for massive homogeneous samples are compared with experimental data, directing special attention to the dependence of this quantity on the electron acceleration energy. It is shown that this dependence generally cannot be neglected. The expression proposed by Hunger and Küchler turns out to be better than that of Love and Scott, although even the better formula can be slightly improved by a small modification.

Analytical Expressions for the Electron Backscattering Coefficient

1989

Phys. Stat. Sol. (a)

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Calculation and comparison of the surface ionization ϕ(0)

1990

Scanning

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An analytical expression for the surface ionization @(O) is derived from fundamentals, viz., the ionization cross section and the angular and energy distribution of backscattered electrons. In order to avoid numerical integrations, a simple formula for the energy distribution of backscattered electrons is presented. The values given by the resulting expression for @(O) are compared with those given by already known formulae and with experimental findings. In general, the agreement is quite satisfactory, although the calculated values generally are smaller than those experimentally found, especially at high overvoltages. This can at least partly be explained by secondary fluorescence excited by the continuous radiation, of which the correction has not been taken into account in the experimental determination of the (P(0) values.

Calculation of depth distribution functions for characteristic x‐radiation using an electron scattering model. II—results

1991

X-Ray Spectrometry

Results obtained from the model of multiple electron reflection are compared with experimental data and values calculated using analytical expressions commonly used in electron probe microanalysis. It is shown that the proposed model quantifies the total amount of generated x‐ray intensity very accurately, the root mean square error obtained from comparison with Pouchou and Pichoir's results being 2.33%. The shape of the depth distribution functions is also predicted very well, as is illustrated by a comprehensive comparison with measured data and with curves obtained from the expressions of Bastin and Heijligers and of Pouchou and Pichoir. Characteristics of the calculated curves and experimental errors affecting the shape of measured depth distribution functions are discussed.