3D extension of the Monte Carlo code MCSHAPE for photon-matter interactions in heterogeneous media

MCSHAPE is a Monte Carlo code for the simulation of gamma and X-ray diffusion in matter which gives a general description of the evolution of the polarisation state of the photons. The model is derived from the so-called 'vector' transport equation. The three-dimensional (3D) version of the code can accurately simulate the propagation of photons in heterogeneous media originating from either polarised (i.e. synchrotron) or unpolarised sources, such as X-ray tubes. Photoelectric effect, Rayleigh and Compton scattering, the three most important interaction types for photons in the considered energy range (1-1000 keV), are included in the simulation with the state-of-art extent of detail. In this paper, the 3D version of the code MCSHAPE is presented. The sample is described using the so-called voxel model. Results from the validation studies and applications of the code to scanning XRF and XRF tomography experiments are discussed.