Improvements in the analysis of calcium‐rich materials by external PIXE using selective absorbers

Abstract

AbstractFor particle‐induced x‐ray emission (PIXE) spectroscopy and x‐ray fluorescence (XRF) spectrometry, the analysis of materials rich in one or two elements may present some difficulties owing to high counting rates and saturation effects in x‐ray detectors. In this case, it is possible to use selective absorbers in order to reduce significantly the intensity of the characteristic x‐rays of major elements with low attenuation for the characteristic x‐rays of other elements. For calcium‐rich materials (cements, shells, bone, teeth and stucco, for instance), the high intensity of Ca Kα, β x‐rays interferes with the detection of x‐rays of lighter and heavier elements. Compounds containing chlorine, argon and silver are good candidates for calcium‐selective absorbers, but only silver and argon absorbers may have a practical thickness when compounds of chlorine cannot be used owing to the presence of fluorescence signals from the absorber in the x‐ray spectra. A selective absorber for Ca Kα, β x‐rays using thin silver films and a flux of Ar–He was tested at an external beam setup for PIXE measurements. In this paper, the improvement in x‐ray detection is demonstrated. Copyright © 2005 John Wiley & Sons, Ltd.