Surface roughness and the use of a peak to background ratio in the X‐ray microanalysis of bio‐organic bulk specimens

Abstract

SUMMARY The use of a net peak intensity and of a peak to background (P/B)‐ratio of sulphur and chlorine is examined in the X‐ray microanalysis of a 2·4% w/w S bulk standard in Spurr's epoxy resin. In calculating the P/B‐ratio, the background intensity is calculated for the same energy region as for the net peak. Analyses were carried out on the flat top of the standard and on the slope running down from the top on the side not facing the X‐ray detector. The results obtained for the peak to local background ratios from the top and the slope yielded a relatively small mean deviation (11%) while net peak intensities ultimately were reduced to 7% or less of the initial value for the flat top. This indicated that a peak to local background ratio is to be preferred in the quantitative analysis of bulk specimens which have poorly defined local tilt and takeoff angles. A second advantage is the inherent correction for beam current fluctuations.