Monte Carlo calculation of buildup factors for 50 keV–15 MeV photons in tungsten up to 15 mean free paths

Abstract

Exposure buildup factor values of tungsten for a point isotropic source in energy range 0.05–15 MeV up to 15 mfp are computed using Monte Carlo N-Particle code. Buildup factors of this study and ANSI/ANS-6.4.3 at some selected energies and penetration depths are compared. Highest discrepancies are observed for high-energy and/or high penetration depths. Highest error occurs at 15 MeV, amounting to 32%. In the energy range 2–6 MeV, our results show smaller values for all penetration depths and vice versa at higher energies.