An easy tool for the Monte Carlo simulation of the passage of photons and electrons through matter

A simple Monte Carlo (MC) algorithm for the simulation of the passage of low-energy gamma rays and electrons through any material medium is presented. The algorithm includes several approximations that accelerate the simulation while maintaining reasonably accurate results. Notably, pair production and Bremsstrahlung are ignored, which limits the applicability of the algorithm to low energies (less than or similar to 5 MeV, depending on the medium). Systematic comparisons for both photons and electrons have been made against the MC code PENELOPE and experimental data to validate the algorithm, showing deviations in the deposited energy smaller than or around 10% in the energy interval of 0.1-5 MeV in light media. The simulation is also valid for heavy media, but with less accuracy as a consequence of the abovementioned approximations. Also X-ray fluorescence is ignored leading to some limitations for photons with energies slightly over the K-shell. The algorithm has been implemented in an open-source Python package called LegPy, which provides an easy-to-use framework for rapid MC simulations aiming to be useful for applications that do not require the level of detail of available well-established MC programs.