ϕ(ρz)-Determination for Advanced Applications of Electron Probe Microanalysis

Abstract

In the last 35 years electron probe microanalysis (EPMA) has developed to a versatile technique for the quantitative analysis of materials on a microscopic scale. This development has been initiated by the pioneering work of Castaing in 1951 (1). Already in 1955 Castaing and Descamps have introduced a basic formulation for the absorption correction to quantify characteristic x-ray data (2). This correction already presumed the knowledge of the distribution ϕ(ρz) of the generated x-ray intensity as a function of the depth ρz inside the target. The authors presented the first experimental procedure to determine this distribution for pure elements by the so called sandwich sample technique. The results of this early work, obtained for several pure elements, became a standard in the field and many authors have examined their theoretical approaches or their Monte-Carlo simulations of ϕ(ρz) by means of these ϕ(ρz) data. In the following time further attempts of ϕ(ρz) determinations by experiments or by theoretical approaches, e.g. Philibert (3), became necessary because a general application of a matrix correction to the whole elemental range, detectable by EPMA, required a generalized analytical description of ϕ(ρz).