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-lay ered materials by X-ray fluorescence spectrometry is presented. In the firs t step, a genetic algorithm is used to obtain the number of layers and, for each layer, an estimate of the elementary concentrations and thickness. Th e second step is a gradient technique to refine this estimate. Good results are obtained for both relatively simple and more complex samples. The latt er require extra depth information, which can be obtained from X-ray fluore scence measurements at various angles of detection.