Assessing scattering effects in annular radioisotope excited XRF

Rayleigh and Compton scattered radiation is used in various correction procedures for quantitative x-ray fluorescence analysis. However, the information derived from the measured scatter peaks is altered by several phenomena in the case of annular radioisotope excitation, causing the calculated results to deviate, often significantly, from the expected values. In this work, we assessed the main sources of inaccuracy when using measured scatter intensities. Monte Carlo simulation was used to trace the radiation transport in the geometric arrangement source-sample-collimator-detector and to estimate the contribution of different effects to the measured Rayleigh and Compton scatter peaks. The information obtained in this way was used to extend the IAEA-QXAS standardless fundamental parameter approach to the case of annular radioisotope excitation and to formulate a method to correct for spurious fluorescent peaks appearing in blank measurements. Copyright (C) 2004 John Wiley Sons, Ltd.