Monte-Carlo simulation of projections in computed tomography

Results from Monte Carlo simulations of two-dimensional projections for a simple real sample (an aluminium cube with a cylindrical hole filled by air or steel) in a realistic experimental environment are presented. A meaningful comparison with measurements was therefore possible. Coherent and incoherent scattering as well as excitation of fluorescent radiation are accounted for; multiple sequences of these interactions are followed up to a selectable order. Such simulations are important aids to modern metrological applications of computed tomography where the dimensional accuracy of hidden or inaccessible components of work pieces is determined. The complex process requires a high level of optimization of the instrumental parameters for each sample type whereby the accurate simulation of the physical interactions between X-rays and the sample material is a supplement and alternative to time consuming measurements.