Comparison of X-Ray Backscatter Parameters for Complete Sample Matrix Definition

Abstract

Equations for computing sample absorption coefficients and matrix corrections from fundamental parameters require measurement or prior knowledge of all bulk element concentrations for samples of finite thickness. Uses of these equations in commercial software have thus required either 1) “similar” standards, 2) limited applications to metal alloys, oxides or specially-prepared matrices of known composition, or 3) user supplied definitions of bulk light element concentrations. A fourth option, which provides superior analytical flexibility, is the use of backscattered x-ray intensities with element scatter cross-sections to define the unmeasured light-element component of the sample matrix. Backscatter intensities constitute the only spectral basis for routinely characterizing the light-element component of geological, biological and other materials which contain significant H, C, N, O, etc. They thus offer a unique basis for utilizing fundamental-parameter matrix corrections in the general case of unknown samples without standards.