Pair production contribution effect on the calculation of gamma ray dose buildup factor for water and graphite in the energy range (4–10) MeV

Publication date: Available online 5 February 2018Source: Journal of Radiation Research and Applied SciencesAuthor(s): Laith A. Al-Ani, Hanan Mohammed JawadAbstractGamma ray buildup factor for two shielding materials, water (Zeff = 7.42) and graphite (Z = 6) for isotropic plane source normally incident within the energy range 4–10 MeV and up to 5 thickness mean free path has been studied. This research has been achieved by writing a simulation computer program in (Visual Basic language version G) and applied depending on Monte Carlo simulation method. The contribution of annihilation effect on the calculation of gamma ray dose buildup factor has been studied for both graphite and water. The results indicated that the calculated values of dose buildup for plane source, when ignoring the contribution of pair production, is less in comparison with the case when the contribution of pair production is taken into consideration. However, the contribution of Compton effect is still more predominant than the effect of annihilation within the range of energy (4–10) MeV.

Source: Journal of Radiation Research and Applied Sciences - July 5, 2018 Category: Physics Source Type: research