A correction method of matrix, density and thickness effects in thin samples analysed by X-ray fluorescence spectrometry

Abstract

This paper deals with X-ray fluorescence spectrometry of powdered materials deposited on collection filters. The general applicability of this method is limited because the spectral response is affected by sample density and thickness and interelement effects may occur due to the specimen composition. The present work is aimed at contributing to the solution of the above mentioned problems, and reports a mathematical correction method which changes fluorescence intensity measurement data into fluorescence intensity values free from density and thickness effects. The correction of the thickness effect was obtained by overlapping the powder sample with a standard pellet containing some reference elements. The method allows the evaluation of the thickness of the unknown samples by measuring the intensity decrease of the X-ray fluorescence radiation coming from the reference pellet and passing through the unknown sample. These data are used to correct the intensity fluorescence values of the unknown samples. A computer program to elaborate spectral data by means of different and selected mathematical algorithms was set up.