Relative total L-subshell X-ray emission intensities and their impact on the fitting of complex X-ray fluorescence spectra

Abstract

Relative total L-subshellX-ray emission intensities, IL2/IL3 and IL1/IL3, are reported for the elements Er, Tm, Yb, Hf, Ta, W, Pt and Au, measured using approximately monoenergetic X-rays at 17.4 keV. X-ray spectra were recorded using a filtered X-ray tube source and a silicon drift detector. Careful fitting was used to determine the intensities of the individual line transitions, accounting for line broadening and detector artefacts. The line intensities were summed to obtain the L1, L2 and L3 total X-ray emission rates. Relative total L-subshell emission intensities were also calculated using recommended values of subshell photoionization cross sections, fluorescence yields and Coster–Kronig transition probabilities. We find poor agreement between these accepted literature values and our experimental results. A simple modelling exercise was conducted to explore the impact on fitting complex L-shellX-ray fluorescence spectra using inaccurate literature values for line intensities and total subshell X-ray emission rates. We find that large errors can be introduced when fitting with incorrect values for the total relative X-ray emission from different L-subshells. Copyright © 2017 John Wiley & Sons, Ltd.