Absorption correction in electron probe microanalysis

The absorption correction factor f (χ) is calculated by using an empirical equation based on a new shape of the x‐ray depth distribution function Φ(ρz). It assumed that Φ(ρz) increases firstly linearly with the depth ρz up to the depth ρz m at which the function Φ(ρz) reaches its maximum value Φ m , and subsequently the function Φ(ρz) decreases exponentially with increasing ρz. The proposed f (χ) equation is a function of the parameters ρz m , Φ m and the mean depth of x‐ray production ρz . Based on Monte Carlo calculations, the variation of these parameters with the target atomic number Z , the incident electron energy E 0 and the critical energy E c was studied and empirical expressions were deduced. The calculated parameters were compared with experimental results. The factor f (χ) was calculated and compared with some measurements. The comparison gives an RMS error of 1.88%. The proposed equation was applied to 680 microanalysis data (including light elements). The results gave a relative deviation of about 3%, compared with 4.27% obtained by the quadrilateral model. For high absorbing systems (absorption factor ≤0.5), the present model gave an RMS error of 4.72% compared with 8.18% obtained by the quadrilateral model.