Abstract
The Monte Carlo method was applied using the PENELOPE code to simulate the transport of particles in two different x-ray tubes. This method is considered the most important and accurate for simulations and calculations in different branches of science, including medical physics. The tubes were modeled according to the manufacturer’s specifications, and the simulations were divided into two stages due to the computational time. The scope of the work was to obtain in greater detail photon spectra of different qualities of beams in the orthovoltage range used in radiotherapy, since few works have, yet been developed for this energy range. A detailed analysis was carried out by comparing to the spectra results obtained using the SpekCalc software for the different qualities of radiation in the two stages. Mean energy values along with the first and second half-value layers (HVLs) of each energy were determined with the respective differences between them. Different discrepancies were found in most cases, and so it is vitally important to consider each situation independently. Finally, secondary electron energy spectra in the second stage of each quality were presented with their respective mean energies, an important parameter considered in the dose deposition of the different experimental geometries that use such qualities.