The number of ionizations on a given j shell in any electron-bombarded target has been calculated analytically by means of the Bethe formulae. A general formula for the atomic number correction has been derived in the form of an equation using parameters that are functions of target composition and accelerating voltage. This equation allows the calculation of the penetration effect to be readily carried out. The electron range, in terms of beam energy, has also been calculated. Finally, it is shown that the correction is different in the case of thin-target analysis.

When used to determine the concentrations of chemical elements in samples, X-ray intensity measurements are processed by correction programmes. These measurements are now usually obtained with fully or partially automated instruments. In order to suppress useless computations on sets of results containing rogue values, statistical tests must first be applied to the original experimental data. From an economic standpoint, it may also be worthwhile to reject the outlying counts automatically rather than discard complete sets of measurements. Statistical tests permitting the detection of outliers in groups of results are described.

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Electron probe microanalysis, associated with electron microscopy, of thin foils of gold-silver alloys has been made using thin fods of pure elements as standards.Theoretical bases are discussed. Specimens and standards were prepared by vaporization in vacuum and their thickness accurately measured. The anomalous emission effect does not seem to introduce errors in these experiments.