The multiple scattering calculations, inherently implemented in all widely used, general–purpose Monte Carlo codes, play a critical role in the determination of any expected dose yield and are directly related to volume damage effects. Small changes in multiple scattering (lateral mainly), and therefore in the corresponding particle trajectories, can lead to significant changes in the affected target or detector irradiated areas. This effect may be critical in the ion beam modification of materials, as well as, in hadron therapy applications and – to the authors’ best knowledge – it has never been thoroughly investigated in the past.
Thus, the aim of the present work is to examine the differences in the multiple scattering calculations, concerning protons, between GEANT4, FLUKA, MCNP6, PHITS and the widely used SRIM2013 compilation and to compare and benchmark the obtained values against the experimental results presented in the past for a variety of targets.
More specifically, in all Monte Carlo codes, protons were generated as beam particles at 158.6 MeV and were subsequently transported, impinging on a variety of thin and semi-thick (ranging from ~0.08 to 8 cm), pure, single–element targets, such as aluminum, beryllium, copper and carbon, which are typically used as shielding materials or components in complex devices. An attempt was also made to additionally examine a number of commonly implemented compounds. The obtained results, corrected for the effective distance between the target and the sampling surface (which critically depends on each target thickness), show small deviations for specific target element and thickness combinations. The final comparisons are presented in graphical form and the observed similarities and discrepancies are discussed and analyzed. Since multiple scattering calculations, however, have not yet been fully benchmarked against experimental data over a broad energy range, the final assessment of the obtained results relies on the user.