Monte Carlo prediction of XRF K and L spectral line intensities excited by discrete energy photons in pure samples

A Monte Carlo Computer program is developed for the simulation of X-ray fluorescence phenomena in pure-element samples so that all the major K or L spectral line intensities can be separately predicted with high accuracy. The exciting discrete energy photons are obtained from a Cd-109 annular radioisotope source used in a characteristic source-target-dedector geometry. Several discshaped pure-element foils are counted under vacuum and net intensities under all the major K or L peaks are determined. These experimental results are then compared with the corresponding Monte Carlo predictions. The characteristic X-ray energies of the chosen pure samples cover the full range in which the Cd-109 source is used for XRF analyses. In the Monte Carlo program variance reduction techniques are extensively used so that every followed photon history yields a detector response. The obtained accuracy, being well within the unavoidable counting statistics and uncertainties in the fundamental parameters, indicates that the program is working rather well without any deterministic errors and that it is suitable for adaption to quantitative multielement analyses. (author)