voxTrace: A voxel-based Monte-Carlo ray-tracing code for the simulation of X-ray fluorescence spectra

Abstract

Confocal micro-X-ray fluorescence analysis (CMXRF), using polycapillary optics, is a powerful technique for the non-destructive investigation of the three-dimensional elemental distribution of samples from many different research areas, including biology, cultural heritage and material science. To solve the problem of the quantitative interpretation of CMXRF measurements, voxTrace introduces a new fundamental Monte-Carlo ray-tracing approach, to simulate the measured spectra. This enables the consideration of effects such as secondary excitation, elastic and inelastic scattering. Furthermore, measurements with step sizes between measurement points smaller than the average confocal volume can be interpreted without complicated sample reconstruction algorithms. Solving this problem of high computational effort, in reasonable timescales, is made feasible by the effective use of graphics processing units (GPU) with CUDA.