Using Geant4 Monte Carlo toolkit to evaluate a low power X-ray tube generator configuration

Monte Carlo technique has been widely used as an important tool to develop new irradiation equipment, prototype medical equipment parts, and test methodologies for dosimetry. In this manuscript, we present a methodology to design a low power X-ray tube generator using the Geant4 Monte Carlo toolkit. The simulations were performed considering a large number of variables, namely, the material composition of the target track, the window thickness, and the air pressure of the X-ray tube. The X-ray production was simulated considering monoenergetic electron beams impinging on targets of tungsten and copper with incident kinetic energies ranging from 20 keV to 60 keV and initial divergences from 5° to 30°. For the polyenergetic emission, a conservative approach with Gaussian energy distribution was adopted. The analysis indicates that among the evaluated parameters, the incident kinetic energy, and the target material produced the most notable changes in the spectra shape and conversion efficiency (CE), significantly impacting the X-ray tube design. The studies provide a reliable methodology to explore general configurations for X-ray tube generators, defining the best geometry, material compositions, and thicknesses to be used on spectroscopy applications.