Simulation of X-ray tubes for imaging applications

This work describes the simulation of X-ray tubes used in imaging applications. The cross section for the electron impact ionisation of the K-shell for selected materials, and given by different sources, is analysed. An enhanced version of the EGS4 code incorporating different models to deal with ionisation of the K-shell by electron impact is briefly described. The code is then used to simulate photon spectra produced in X-ray tubes operating at energies below 100 keV. The results obtained for Ag and Mo targets in transmission and reflection geometries, and for different tube voltages, are then benchmarked against experimental data. The results show an overall good agreement between simulated and experimental data. It is shown that the accuracy of the result depends on the model used to deal with the ionisation of the K-shell. When appropriate models are in use, simulated and experimental spectra agree within 15% at the K_α peak