A Two-Step Approach toward Model-Free X-Ray Fluorescence Analysis of Layered Materials

A two-step fundamental parameter method for model-free analysis of thin-layered materials by X-ray fluorescence spectrometry is presented. In the first step, a genetic algorithm is used to obtain the number of layers and, for each layer, an estimate of the elementary concentrations and thickness. The second step is a gradient technique to refine this estimate. Good results are obtained for both relatively simple and more complex samples. The latter require extra depth information, which can be obtained from X-ray fluorescence measurements at various angles of detection.