The implications of these results for the analysis of transition-metal compounds by electron probe microanalysis as well as strategies to account for self-absorption effects are discussed.Įlectron probe microanalysis (EPMA) is an analytical technique widely used for the determination of the chemical composition of materials (Llovet et al., Reference Llovet, Moy, Pinard and Fournelle2021).
In contrast, X-ray intensities calculated for metallic Zn and Cu do not differ significantly from those obtained using the conventional approach. We find that calculated X-ray intensities depart increasingly, for increasing electron beam energy, from those obtained assuming a narrow X-ray line and a single fixed absorption coefficient (conventional approach), with a maximum deviation of $\sim$15% for Ni and of $\sim$10% for Fe. To assess the error due to neglecting self-absorption, we calculate the L $\alpha$ X-ray intensity emitted from metallic Fe, Ni, Cu, and Zn targets, assuming a Lorentzian profile for the X-ray line and taking into account the energy dependence of the mass absorption coefficient near the absorption edge. This effect, which occurs when a broad X-ray line is located close to a broad absorption edge, is not accounted for by matrix corrections.
Electron microprobe-based quantitative compositional measurement of first-row transition metals using their L $\alpha$ X-ray lines is hampered by, among other effects, self-absorption.
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