Monte Carlo Simulations of X-ray Generation and Detection

The employment of Monte Carlo simulations in the applied nuclear physics techniques has increased with the data processing capabilities of the commercial personal computers. Since the inclusion of the low-energy electromagnetic interactions in GEANT4, this Monte Carlo simulation toolkit has produced results which reveal its promising utilization in radiation dosimetry, radiation protection and medical applications. With the GEANT4 toolkit, interactions of electrons and photons with matter can be simulated down to energies as low as 250 eV. The present work shows simulation results of X-ray generation from a typical X-ray tube by impinging electrons on a tungsten target, and filtering the produced photon beam with a beryllium window. In this process, characteristic and bremsstrahlung radiation are produced. Rayleigh, Compton, photoelectric and pair production interactions can be included in the transport of photons through the environment. The spectral analysis of the photon beam is performed by simulating a cadmium zinc telluride detector positioned in the radiation field. Different filters can also be placed in the radiation field to produce the desired attenuation. Comparisons with experimental data show that the simulated spectra reproduce very well the reality, indicating that the GEANT4 toolkit can be a good choice for future simulations of experimental conditions for dosimetric purposes, such as dosimeter responses and dose estimations