Monte Carlo simulation of the backscatter region in photon-excited energy dispersive X-ray fluorescenceespectra

The backscatter region of energy-dispersive X-ray fluorescence spectra obtained by a typical radioisotope system is examined in detail. A Monte Carlo simulation program which incorporates all the information on photon scattering processes including electron momentum distributions in target atoms, form factors and scattering factors for the cross-sections is presented. The program uses extensive variance reduction techniques and has the option of simulating any type of either single or any specified combination of multiple scatters or the complete process as appears in a real detector response spectrum. Based on several simulated spectra various conclusions are reached including that the energy spread of Compton peaks depends mainly on the broadening effect of electron momenta together with detection system resolution, and that the intensity of double scatters is roughly an order of magnitude lower than that of single scatters for thick targets. (author)