Electron modes simulation of a Siemens-Primus-Linac at 10, 12, and 14 MeV with various field sizes

The electron mode of a Siemens Primus linear accelerator (SPLA) is simulated using Monte Carlo (MC) simulation, BEAMnrc, with various field sizes 10 × 10, 15 × 15, and 20 × 20 cm2 at different e-beam energies of 10, 12, 14 MeV. To verify the simulation outcomes, measured data will be compared to them. A SPLA's electron beam is simulated using the BEAMnrc based on the EGSNRC code. At the end of each field size simulation the BEAMnrc will be used to acquire the phase-space (PhSp) file. Moreover, the PhSp file is utilized by DOSXYZnrc and BEAMDP to estimate the energy distribution and percentage-depth-dose (PDD) data for various field sizes. The results show minor PDD variations for the field sizes 10 × 10, 15 × 15, and 20 × 20 cm2. However, for all energies, the most considerable discrepancies in RMAX, R90, R80, and R50 between computation and experimental outcomes are less than 2 mm. Also, all field sizes were given surface dosages ranging from 2.6% to 8%. On the other hand, the variations in surface dosages quickly faded in the buildup area, reaching 0% within the first 3 cm and having no discernible impact on clinical outcomes. The MC simulation with BEAMnrc code for e-beam energies of 10, 12, and 14 MeV was shown to be accurate in replicating the SPLA's head with different field sizes. Also, the mean dosage is the acceptable limit in the buildup area for all energies and all field sizes.